Friday, November 29, 2013

Warming Trend Kicks-in over the Weekend

Many of you rose this morning to a heavy frost, with morning lows dropping into the 20°s for a majority of WAFB communities for the second consecutive day.
As a reminder, Steve did a little extra digging earlier this week and found that our Thanksgiving low of 26° was the coldest Thanksgiving morning since at least 1930! With a morning low of 26° for Thursday and a low this morning at 27°, that’s the coldest back-to-back November mornings for Baton Rouge since 1991. In fact, there have only been a half-dozen occurrences of back-to-back November lows this cold since 1930!  20°s are indeed somewhat uncommon for baton Rouge in November: Friday wass only the 30th November day on the books with a low in the 20°s based on the past 84 Novembers.
And there is a chance that Metro Airport (BTR) could dip to freezing again on Saturday morning. Again, not a record, but there have been fewer than 20 occurrences since 1930 with three consecutive freeze days during November for the Red Stick (based on daily records back to 1930).
So about that forecast for the rest of the Thanksgiving weekend: even with cold morning wake-ups, the warming trend we’ve been promising started today and will continue. You have to admit that today wasn’t bad at all even with that bitterly-cold start thanks to the day’s abundant sunshine and afternoon readings reaching the 60°s for most of us.
And even with another cold forecast for Saturday’s sunrise, sunshine and highs in the mid 60°s for Saturday afternoon sounds good!
We keep the forecast dry through the weekend, although we’ve got some clouds returning on Sunday. But we skip a freeze for Sunday morning and Sunday afternoon temps should climb into the mid to upper 60°s for most WAFB neighborhoods. We’ll put a slight chance of rain in the forecast for Monday followed by a mainly-dry Tuesday. At this point it looks like daytime highs will approach 70° by Monday and stay in the 70°s through the work week. We’ll go with modest rain chances for Wednesday into Thursday and 'up' those rain percentages for Friday.

Wednesday, November 27, 2013

Hard Freeze Warning!

By Jay Grymes & Steve Caparotta

Thought it was cold for Wednesday’s wake-up?  Wait until Thanksgiving’s sunrise -- many of you will be 10° or more colder than earlier today!
That’s why a HARD FREEZE WARNING will go into effect for the northern half of the WAFB viewing area overnight and extend until 9:00am Thursday morning!  And even our southern viewers will be under a FREEZE WARNING.

We’re calling for a morning low of 25° for the Capital City, with low 20°s for many WAFB communities north and east of the metro area.  As we mentioned yesterday, we still think freeze durations will run up to 10 hours or more for parts of metro Baton Rouge, with freezing temps lasting as much as 14 hours or more on the north side of the LA/MS state line.
The freeze will extend all the way to the coast -- we’re calling for several hours at or below 32° even for Houma and Morgan City.
Protect the tender plants, check that the pets have a place to get out of the freezing temperatures, and PLEASE be extra careful if you’ll be using space heaters or other types of supplemental heat.  Check on the elderly too.
Steve did a little “data mining” to compare this Thanksgiving morning forecast with all past Thanksgiving days.  While the record low for November 28th is 23° (set in 1938), the record low for a Thanksgiving Thursday (based on records back to 1930) is currently 27° -- looks like tomorrow morning will become the coldest Thanksgiving morning in more than 80 years!

The really good news is that while it will get bitterly cold for Thanksgiving morning, we’ll rebound nicely through the day under sunny skies.  Highs for just about all of us should reach the 50°s, which will feel pretty good given that we’ve not seen readings in the 50°s since Sunday afternoon!
Most WAFB communities should expect another freeze on Friday morning -- just not as cold and not nearly as prolonged.  Friday will be another sunny day, with afternoon highs getting up around 60° for the Red Stick -- good news for the Black Friday marathon shoppers.
And the warming trend continues into the weekend.  Some WAFB neighborhoods north and east of the Capital City could see another brief, light freeze for Saturday morning but mostly sunny skies will take just about everyone well into the 60°s by the afternoon.  By Sunday, some viewers will see temps up near 70° for the afternoon.

We’ve got scattered rains in the forecast for Monday and Wednesday with a dry Tuesday in-between.  But maybe more importantly -- given this week’s chill -- temps will be running normal to above-normal for the opening days of December.

Tuesday, November 26, 2013

Clearing, Staying Chilly on Wednesday!

By Jay Grymes & Steve Caparotta

We spent the night waiting for a chillier air to arrive ... but it just didn’t happen for Baton Rouge.  In fact, morning temps at Metro Airport (BTR) ended uprising between midnight and 5:00am rather than falling, only to start to drop again when the morning rains arrived.
Although there were breaks in Tuesday’s rains, the clouds, the northwest winds and the steady temps in the 40°s made for a day that was even drearier than Monday.  As we hinted yesterday, rains tapered off after the morning and many of you had a prolonged run of rain-free hours through the middle of the day.  
Yesterday we described a double-barreled rain event for today, with the first round of rain tied largely to the surface low passing to our south from west-to-east with energy from the southern branch of the jet stream.  That would be followed by a second round of showers tied to the upper-level low that was positioned over Texas on Monday.  That gameplan appears to have been on-target, with wet weather moving back into the area this evening.

It all clears out of the viewing area before sunrise, giving us a dry Wednesday morning commute.
So what about that talk of a frozen “wintry mix?”  Chances are still fairly low, but we still can’t entirely rule out the potential that keen-eyed viewers up along and north of the LA/MS state line might see a brief shot of sleet or even a couple of ice pellets.  Note that the window of opportunity is small -- only a handful of hours -- and seems limited to the evening hours before midnight.
Not to worry: even those that might see a “winter mix” won’t have to deal with accumulations nor should it be an issue for the Wednesday morning drive.
So we say “goodbye” to the rain and open Wednesday with mainly clear skies at sunrise, but we’ll be trading the rain for more cold.  Many of you to the north and east of Baton Rouge will awaken to a light freeze for Wednesday morning -- indeed, some metro BR neighborhoods could see frost and a brief light morning freeze although we’re officially posting 33° for the forecast low at Metro Airport.  Later in the day, even with the sunshine, Wednesday stays chilly with highs topping out in 40°s for the third straight day.
But it gets MUCH colder for Thursday morning!  We’re going with a low of 25° for the Red Stick on Thanksgiving morning with lows dipping into the low 20°s along and north of the LA/MS state line. That has prompted the National Weather Service to issue Freeze & Hard Freeze Warnings for most of the area late Wednesday night into Thursday morning.

Cold?  Boy, you bet … Baton Rouge’s record low for November 28th is 23°, set back in 1938. We’ll get uncomfortably close to the record!
The Thanksgiving morning freeze will extend all the way to the coast.  And remember, in many cases the duration of the freeze is more important and more damaging than the actual low temperature.  For the time being, we’ll go with BTR temperatures at or below freezing for roughly 10 hours or so.  For WAFB communities along and north of the LA/MS state line, durations could exceed 14 hours!
Remember, double-digit freeze durations are more than enough to damage the tender vegetation, so take precautions.
But what about those exterior pipes?  For most outdoor pipes up against the side of the house, this is not likely to be a pipe-busting freeze.  But for those living north of the I-10/12 corridor, you should consider wrapping any exterior pipes that have a history of freezing.
And needless to say, our area strawberry farmers as well as local gardeners with young, outdoor citrus need to set-out the protective ‘blankets.’
Assuming that BTR drops to 25° or lower for Thanksgiving morning, when was the last time we had a freeze like this?  Metro Airport dipped to 26° on March 3rd -- the coldest day of 2013 thus far.  If BTR drops to 25° or below, we have to go back to January 2011 to find a day as cold or colder.
Now understand that a low of 25° for Baton Rouge is not all that uncommon: there have been more than 300 days with lows of 25° or below since 1930 (84 years).  In fact, over those 84 years, there have only been 10 years without at least one day when the minimum dropped to 25° or below for BTR.   Yet somewhat interestingly, 4 of those 10 years have occurred since 2005.
While we’ve seen a handful of “25° free” winters of late, not all recent winters have been ‘warm’ throughout -- for BTR, there were 7 days in January 2010 with lows at or below 25° and 9 days during the 2010-2011 winter with lows of 25° or below.
So, a 25° low may not be all that rare for Baton Rouge, but a 25° reading during November is uncommon for the Capital City.  To put in into perspective, the statistical “average first freeze” for Baton Rouge doesn’t occur until the last week of November -- generally right around the Thanksgiving holiday and rarely more than a light to moderate freeze.
(By the way, our first freeze for this season was almost two weeks “early,” with BTR briefly slipping to 32° on the morning of the 13th.)
Since 1930, there have been only 14 November days with minimums at or below 25° for Baton Rouge.  Three of those days were in November 1938 and two more occurred during November 1976.  That leaves just 9 November occurrences over the remaining 82 seasons -- or roughly once every 9 years, on average, that BTR has a November morning at or below 25°.
By the way, the last time Metro Airport’s thermometer dipped to 25° during November was back in 1992, so that statistic suggests that we were a long overdue.
For the trivia fans, the earliest 25° or below reading Baton Rouge was 22° on November 15, 1940.  And the all-time lowest November reading for BTR?  21°, recorded on November 30, 1976.
Thankfully, temps will climb into the 50°s for just about everyone under sunny skies by Thanksgiving afternoon, providing a much-welcomed thaw.  Most WAFB communities can expect another freeze for Friday morning, but the Friday freeze won’t be nearly as cold nor as prolonged.  Then we’ll head into a warming trend through the weekend.  Expect dry weather throughout the Thanksgiving weekend with highs back into the 60°s for Saturday and approaching 70° for Sunday.

Rain is back in the forecast by Monday, just without the freezing temperatures this go-around! 

Monday, November 25, 2013

Staying Damp & Cold on Tuesday

By Jay Grymes & Steve Caparotta

So ... how’s your home-heating system been behaving?  You’ll want it in tip-top shape this week!
The break from the Saturday dampness was certainly a short one.  After a sunny but cool Sunday, the clouds returned overnight and rain is back.  If you’ve been checking WAFB’s on-line Interactive Radar or your Storm Team App, you’ve seen a broad swath of rain advancing from the west and southwest.
This round of rain is going to be with us for a while.  We’re not concerned about any severe weather with this forecast cycle, but you may hear some rumbles of thunder between now and Tuesday afternoon.
There are two features at play for our rainy Monday night and Tuesday, and both mean “wet” weather.  A surface low currently over the western Gulf is headed northeast towards the central Gulf Coast and join forces with an eastbound upper-level low currently over the Texas Panhandle.  These two systems are sure to give Louisiana a true winter feel over the coming days -- not just wet but very cold too!
In fact, highs over sections of northern Louisiana topped-out in the 30°s today, with the threat of freezing rain prompting a “Winter Weather Advisory” earlier in the day across the northwestern parishes!  While it wasn’t nearly that cold here, it seemed as though the clouds and rain made it feel colder than it was.
For WAFB viewers, we’re looking at lows ranging from the upper 30°s (north) to low to mid 40°s (south of Baton Rouge), with lows around 50° near the coast.  Metro Baton Rouge can expect a low right around the 40° mark.  Most WAFB communities can expect to remain in the 40°s through a dreary and wet Tuesday.  While the surface low will have moved towards the Southeast U.S. by Tuesday afternoon, the upper low will still be positioned over the lower Mississippi Valley.
Scattered, mainly-light rains will continue into Tuesday evening and into the overnight hours but should be out of the area well before Wednesday’s morning drive.  At the same time, early Wednesday temps will fall to around freezing under clearing skies for neighborhoods along and north of the I-10/12 corridor.

You may have heard some chatter about the potential for winter precip late Tuesday night into early Wednesday.  It all depends on just how quickly the freezing temps arrive and how long the ‘backside’ rains (rains trailing the surface low) persist.  We concede a slight chance for a ‘winter mix’ (sleet & rain) near and north of the LA/MS state line.  In fact, we won’t be surprised to hear a couple of Weather Watcher reports of sleet and/or ice pellets from around the northern half of the WAFB viewing area by late Tuesday evening.  But there won’t be any accumulations and it should not result in any hazard concerns for Wednesday’s morning commute.
Sunshine breaks out for Wednesday, but it stays cold, with highs once again in the 40°s for much of the viewing area.
Thanksgiving morning?  Very, very cold under mainly clear skies -- a ‘Hard Freeze’ will extend over most of the WAFB region with lows for metro Baton Rouge plummeting to the mid 20°s and low 20°s for viewers to the north and east of metro BR.
The Thursday morning freeze will reach all the way into the coastal parishes.  Although we expect a sunny day for Thanksgiving, temps will be slow to warm and struggle to reach 50° around the ‘Red Stick.’  That means a fairly prolonged freeze -- for now, we’re thinking temps will be at or below freezing for 10 hours or more across metro BR with freeze durations exceeding 12 hours for areas north and east of the Capital City.  We’ll get a better handle on these numbers as we get closer to Thursday.

You may be thinking, when was the last time we had a freeze like this?  Metro Airport dipped to 26° on March 3rd -- the coldest day so far this year.  If the airport drops to 25° or below, we have to go back to January of 2011 to match it.  Baton Rouge’s record low for November 28th is 23°, set back in 1938. From what we’re seeing right now, we could get uncomfortably close to a repeat.
Metro BR can expect another freeze for Friday morning, then we’ll head into a warming trend and say goodbye to freezes for the time being.  We expect dry weather through the Thanksgiving weekend with highs back into the 60°s for Saturday and up around 70° for Sunday.
Rain is back in the forecast for next Monday.

Friday, November 22, 2013

Showers, Much Cooler on Saturday

By Jay Grymes & Steve Caparotta

This Friday/Saturday rain forecast has been one of the tougher nuts to crack in quite some time. Yesterday afternoon, the forecast guidance was suggesting that today’s rains would be scattered at best for today, and mainly a late afternoon and evening occurrence.

Now here we are and by 3:00pm just about everyone has received at least a little rain thanks to a southbound band of showers that raced across the viewing area. In fact, Titan9 Doppler even picked-up a couple of lightning flashes with the rain line as it approached the coast.

Today’s clouds and rains kept temps a little cooler than expected, with highs for many topping out close to 70° or so. But that rain has also appeared to settle down the atmosphere, so we’ll go with just isolated to possible scattered rains for the rest of the afternoon and evening. Although fields will be wet for area high school football, the turf shouldn’t be too sloppy this evening and game-time temps will remain in the 60°s.

Light to moderate rains will return overnight, with the rains continuing into Saturday morning and afternoon. Although the cold front will have passed through the viewing area and is expected to be draped along the southeastern Louisiana coast by sunrise, “overrunning” (clouds and rains on the ‘backside’ of the front) will still be an issue for Saturday plans, including the LSU-Texas A&M game.

And remember, with the front moving through the BR metro area overnight, the warmest hours on Saturday will be during the morning, with Saturday’s official high likely to be recorded near midnight. While pre-dawn temps for Saturday will start out in the 60°s for the ‘Red Stick,’ many of us will be in the 50°s for sun-up and that’s what we expect temperature-wise for LSU’s 2:30pm kick-off. In fact, the thermometer likely shows a slow fall through the afternoon, with readings in the low 50°s by game’s end. Add in an overcast sky and breezy north winds, and you can expect a cool and “dampish” afternoon in Tiger Stadium -- dress for it!

This overrunning set-up for Saturday could even mean occasional drizzle through the afternoon and even into Saturday evening before coming to an end. Clouds should start breaking up early Sunday morning but it will be a very chilly start to the day, with Sunday morning lows in the 30°s for most WAFB communities. Skies should be fair to partly-cloudy by or before Sunday afternoon, but the Canadian air mass in place will keep things cool with highs only in the 50°s.

Monday morning will be even colder -- some viewers could see a brief, light freeze for Monday’s wake-up.

Unfortunately, the dry-out that kicks-in on Sunday will be very short-lived as the next rain-maker approaches from the west. An upper-level low will help to energize a developing surface low over the western Gulf, with the two features making “rain likely” during the latter half of Monday and extending into Tuesday.

A few showers could linger into Wednesday morning, but the rest of the work week looks dry with daytime highs likely to stay in the 50°s through Thursday, at least. In fact, the extended guidance suggests that we could see a second surge of cold air during the week that delivers another light freeze for Thanksgiving morning.

Now that Melissa is gone, all looks quiet over the tropics as we head towards the official end of the Atlantic Hurricane Season!

Thursday, November 21, 2013

More Clouds, A Few Showers on Friday

By Jay Grymes & Steve Caparotta

Although it was mainly-dry across the WAFB viewing area, the clouds hung over us throughout the day.  Get used to it: the clouds will stay with us this evening and overnight, and continue right through Friday.
While we can’t rule out a spotty sprinkle or two tonight into Friday’s wake-up hours, just about everyone stays dry.  Even those that might see a passing shower or two overnight will barely get enough rain to so much as wet the sidewalk.  Temps tonight and into the morning will stay in the 60°s for just about everyone as today’s muggy air mass stays in place.
What may be an issue for Friday’s wake-up and morning drive could be areas of fog.  In fact, don’t be surprised should a DENSE FOG ADVISORY be in place for parts of the viewing area when you awaken Friday morning.
Our thinking for Friday and Saturday has undergone a bit of a change.  A cold front is still expected to push from northwest-to-southeast across the viewing area, with the front working through the Baton Rouge metro area late Friday night.  We think that the front will be draped close to the coast by Saturday’s sunrise with the front out over the Gulf waters by Saturday afternoon.

Here are the key changes we anticipate.
First, pre-frontal rains will be somewhat limited -- we’re only posting a 30% to 40% rain chance for Friday afternoon and early evening.  Indeed, rain chances will top-out at 50% to 60% from very late Friday into the first half of the day on Saturday.  While we can’t rule out a rumble or two of thunder as the front moves through, this will not be a very active frontal passage.  Rain totals will come in at well under 1” for just about everyone … in fact, most of us will likely see less than one-half-inch.
Second, it seems as though the main effects of the front and changing air masses will not be felt until after the front has passed us by.  Overrunning clouds and showers (rains and clouds behind the surface front) will mean some pockets of light rain through Saturday morning and could even provide passing light rains well into the afternoon.  In fact, the way it looks right now, clouds will persist into most or all of Saturdayafternoon and evening for most or all of us.
What’s more, Saturday will be one of those upside-down temperature days, with 60°s just after midnight but readings falling throughout the better part of the day.  We’re calling for afternoon temps in the 50°s, dropping into the 40°s by the evening.
For you Tiger fans: (1) cool and damp for the morning and mid-day tailgating and (2) staying cloudy and cool, possibly damp and rather breezy through the game -- dress appropriately!

We’ll dry out for very cool Sunday under a sun/cloud mix with morning lows in the upper 30°s to around 40° for the Red Stick and highs only getting into the mid 50°s.  But the dry-out will be brief: rain is back in the forecast for the latter half of Monday and into the first half of Tuesday as a non-tropical Gulf low slides west-to-east along the coast.

After that, the weather looks dry for the remainder of the work week, but temps remain well below normal.
In the tropics: Melissa is still barely hanging on to ‘her’ tropical classification and should transition into a non-tropical system within the next day or so.

Wednesday, November 20, 2013

Clouds, Rain Returning to the Forecast

By Jay Grymes & Steve Caparotta

After a chilly start this morning, we enjoyed a beauty of a November day with just about everyone climbing into the 70°s for afternoon highs.  Sadly, the clear skies won’t last long.

Clouds will be on the increase overnight, with mostly cloudy skies expected for Thursday’s sunrise.  The “cloud blanket” will keep us much warmer tonight, with Red Stick lows for Thursday’s wake-up expected to be in the 50°s -- 15° or so warmer than earlier this morning.  We’ll stay with mostly cloudy skies on Thursday and warm into the upper 70°s -- plus toss in a 20% chance of light afternoon showers.  Even where it does rain, accumulations will be minimal.
Our forecast is even warmer for Friday, with rain chances on the rise during the latter half of the day as our next cold front approaches.  We’ll go with a 40% to 50% rain chance for Friday afternoon into the evening, with even higher percentages for the overnight period between Friday evening and Saturday morning.
The timing of the weekend front is still a little uncertain, but the first half of Saturday is shaping up to be rather messy.  Although we are not anticipating any severe weather, rain is likely for Saturday morning with scattered rains extending into the latter half of the day.  While the front should get through the Baton Rouge metro area early in the day, “backside” (overrunning) rains behind the front should keep things cloudy and damp into the afternoon.  In addition, once the front moves south of your neighborhood, expect the northerly winds to pick-up as the colder air pours in.

Take note Tiger fans!  Saturday will likely remain cloudy into the afternoon and evening, so that even after the rains have eased-up it will remain rather disagreeable.  Gusty winds coupled with the inflow of chilly, Canadian air may produce one of those days where we see temperatures in the 50°s and slowly falling after lunchtime.
Skies will clear by Sunday, but the cool air remains.  In fact, our extended outlook keeps daytime highs in the 50°s for many of us right into at least the middle of next week!  It won’t get bitterly cold, but the run from Sunday into mid-week shapes up to be the chilliest spell we’ve seen since early March.

Sunday’s dry-out won’t last long either: we’re posting scattered rain s in the forecast for the latter half of Monday with rain likely for Tuesday as a non-tropical low slides from west-to-east across the northern Gulf.
And for you fans of the tropics ... the National Hurricane Center (NHC) changed Melissa’s designation from a sub-tropical storm to a fully tropical system this morning, even though ‘she’ is notably weaker and less organized today compared to yesterday.  Melissa continues to track towards cooler waters and a region of enhanced wind shear, with the NHC expecting the system to transition into a non-tropical (“post-tropical”) storm within the next day or so.

Tuesday, November 19, 2013

Chilly Start for Wednesday

By Jay Grymes & Steve Caparotta

Passing bands of mid- and high-level clouds throughout the day had much of the viewing area in-and-out of the sunshine and slowed the mid-day warm-up, keeping just about all of ‘WAFB-land’ in the 60°s for afternoon highs.  Along the coast, however, not only were the clouds more persistent but Titan9 Doppler also was showing some west-to-east-moving pockets of light rain through much of the day.
Some clouds will linger into the evening nearer to the coast, but for most of us it looks like the last of the significant cloud bands will exit the region by the late afternoon.  That should leave most WAFB neighborhoods under mainly-clear skies this evening and overnight.
Clear skies, light winds and low humidity are the key ingredients for a chilly November morning, and that is exactly what we’ll get for Wednesday’s wake-up.  We’re calling for Wednesday morning lows around metro Baton Rouge to dip to around 40°, with 30°s likely for communities to the north and east of the Capital City.
Berry farmers: we don’t think a ground frost is likely for tomorrow morning, but it could get close if the winds go ‘calm.’
Plan on fair skies for Wednesday afternoon with highs in the low 70°s for the Red Stick.

Dew points (low-level moisture) will be rising throughout the day, climbing into the 50°s by late Wednesday and early Thursday.  Remember, the air temperature can’t be lower than the dew point: this points to a much warmer start for Thursday morning.
Thursday afternoon’s forecast is a little fuzzy.  We’re posting scattered rains -- in the 30% to 40% range -- for the afternoon and early evening.  This is one of those cases where the rains aren’t frontal but rather are produced by mid/upper-level disturbances drifting from west-to-east.  Regardless of the driver, Thursday will not be a big rain event and we expect only very limited thunderstorm action that day.
Into Friday, however, we’re looking at an approaching cold front, “warm” afternoon temps in the upper 70°s and adequate moisture in the air -- all ingredients pointing to pre-frontal showers and t-storms for Friday afternoon and evening.  For now, we’ll go with 50-50 rain chances for the latter half of the day and into the evening.  High School football, take note.
The cold front arrives Saturday.
The front’s timing is still a bit up-in-the-air right now and just a handful of hours either way could mean a big difference for your Saturday plans.  A quicker-moving front could provide a welcomed dry-out for the afternoon, while a slower system spells rain for the better part of the day.  For now, at least, it’s almost a “pick ‘em” for rain at kick-off for LSU-Texas A&M (2:30pm), but rain is likely during the morning tailgating.
Skies clear and the air turns notably cooler for Sunday, with rain returning to the forecast towards mid-week.

In the tropics, Sub-Tropical Storm Melissa is still holding her own, maintaining peak sustained winds today around 65 mph (satellite estimates).  While Melissa offers no threat to land, she remains an interesting system to watch given her sub-tropical status.  The National Hurricane Center (NHC) still gives Melissa better-than-even chances of transitioning to a fully-tropical system, with an outside chance of gaining hurricane strength before succumbing to increased shear and cooler waters in her path.

Monday, November 18, 2013

Drying Out, Cooler for Tuesday

By Jay Grymes & Steve Caparotta

You’ve likely seen some of the array or reports regarding Sunday’s severe weather outbreak in the Midwest. While spring is the peak season for tornadoes nationally -- and that’s true for Louisiana as well -- fall activity is far from rare. Admittedly, the outbreak yesterday was unusual: with well over 500 Preliminary Storm Reports including more than 70 tornadoes, yesterday would rank high among memorable spring outbreaks for the U.S., much less past fall events. Yesterday’s outbreak serves as a reminder that severe weather and tornadic outbreaks are not just a spring concern.

From a Louisiana perspective, nearly 40% of all Louisiana tornadoes occur during the three spring months of March, April and May. However, the state has a secondary peak in November, a month that accounts for nearly 1-in-6 of Louisiana’s past twisters. 

As for our local weather, we started the day off wet, waiting for the day’s cool front to move through the area and head out into the Gulf. By the afternoon, the front was draped along the coast with skies slowly clearing for the northern half of the viewing area. However, radar was still showing some decent rains over portions of the southeastern coastal parishes during the mid-afternoon.

While most of us only saw limited rains through the overnight and first half of the day, Titan9 Doppler radar is indicating some 2” to 4” rain totals over parts of Terrebonne and Lafourche parishes, with a pocket estimated at 5” to 6” in southeastern Terrebonne Parish in the vicinity of Chauvin.

The rains will continue to taper-off along the coast this evening. Most of the viewing area can expect fair to partly cloudy skies through the night and into Tuesday morning. It will be noticeably cooler for Tuesday morning too, with sunrise temperatures for the ‘Red Stick’ running in the mid to upper 40°s. Plan on fair to partly cloudy skies through the day on Tuesday, but highs will top-out in the 60°s for many WAFB neighborhoods, quite a change from this afternoon.

After an even cooler start for Wednesday morning, temps will rebound for Wednesday afternoon as highs return to the 70°s. We’ll also add a very slight chance (10%) for a passing shower on Wednesday afternoon as Gulf ‘return flow’ moistens things up a bit.

After that, the weather turns “wetter” with rain likely on Thursday. And the weather remains unsettled for Friday, especially during the latter half of the day as out next cold front approaches from the northwest. At this point, it looks like the expected colds front will still be draped over south Louisiana on Saturday morning, prompting us to go with “rain likely” through the first half of Saturday.

The rains should be ending from west-to-east during the day on Saturday. While that is a good sign for the Tiger Faithful, it is still too early to say “no rain in Death Valley” for the 2:30pm kick-off against Texas A&M. We’ll keep a close watch on that for you through the coming days. Sunday looks good with lots of sunshine, but it will be quite a bit cooler!

And in case you hadn’t heard, there’s something brewing in the tropics -- Sub-Tropical Storm Melissa is spinning in the central Atlantic. While Melissa offers no serious threats to land, ‘she’ does serve as a reminder that we are still officially in Hurricane Season for the Atlantic basin.

The designation “sub-tropical” means that Melissa has some non-tropical characteristics. Sub-tropical storms tend to be a little broader across the centers -- not as tightly wound -- as tropical storms. They also display cooler temperatures in their cores compared to their tropical cousins. In effect, sub-tropical systems are something of a hybrid between fully-tropical and non-tropical systems. But these systems can transition into fully-tropical storms and that is what the National Hurricane Center (NHC) is anticipating for Melissa. In fact, the NHC has suggested that Melissa could gain hurricane strength briefly before ‘she’ gets too far north.

Friday, November 15, 2013

Even Warmer This Weekend

By Jay Grymes & Steve Caparotta
As expected, we had passing mainly-light showers over the viewing area earlier in the day, but the day’s bigger weather story was about the temperatures: morning lows in the 50°s and highs in the 70°s -- quite a change from the previous couple of days.  The warm-up continues into the weekend -- heaters off, and for many it will be back to the a/c.  We’ve got morning lows for both Saturday and Sunday in the 60°s for the Red Stick region, with highs in the upper 70°s to low 80°s.
We’ve backed-down the rain chances for Saturday and are now going with only spotty (less than 20%) mainly-afternoon showers.  With tailgating highs in the mid and upper 70°s “on the bluff” plus game-time temps hovering around the 70° mark for all four quarters, that should make the Jaguar Nation very happy.
So what about Sunday?
Most of our guidance yesterday had Sunday set-up for “rain likely,” but the latest round of model outputs have muddied the forecast waters a bit.  All three of our popular go-to models -- our in-house PrecisionCast, the American GFS and the European ECMWF -- are “drier” for Sunday-into-Monday compared to yesterday.  In addition, they also seem to be suggesting a slower progression and passage of the front, with rains lingering later into Monday morning.  With the new guidance in mind, we’ll go with scattered rains on Sunday afternoon and evening, with rain likely during the overnight hours into the first half of Monday.
The NWS Weather Prediction Center has also eased back on their regional rain totals for the frontal event, now calling for something more along the lines of 0.25” to 0.75” through Monday.  Severe weather does not appear to be any threat either.
Once the front clears the region during the latter half of the day on Monday, we can expect a noticeable cool-down, but not another polar blast like earlier this week.  We’ll stay dry through the mid-week with no freezes -- in fact, most of us will see lows only fall into the 40°s for Tuesday, Wednesday and Thursday mornings.   Highs on those same three days will be in the mid to upper 60°s.
Well out into the end of next week, early indications from the GFS and ECWMF have the next front arriving in the lower Mississippi Valley around Saturday or so.  Now we all know that a forecast for next weekend is really too far down the road to declare confidently, but it is something to watch in the coming days and early next week.
Still quiet as we head towards the official end of the Atlantic Hurricane Season!

Thursday, November 14, 2013

Warmer, Isolated Showers on Friday

By Jay Grymes & Steve Caparotta
Much of the Baton Rouge metro area missed out on a light freeze this morning, but as we hinted in yesterday’s forecasts, many communities to the north and east of metro BR saw morning lows dip a degree or two lower this morning compared to Wednesday morning.
Based on reports from automated weather stations at airports around the region, Baton Rouge bottomed-out at 33° compared to Wednesday’s low of 32°; New Roads just missed a morning freeze with a low today of 33°.  McComb (Pike Co. Airport) dropped to 30° this morning compared to yesterday’s low of 31°, and farther east, in Slidell, the low was 31° earlier this morning compared to a low on Wednesday that was above freezing.
And now we say “adios” to the winter temps as a steady warm-up is underway.  After highs today in the 60°s, Friday morning lows will only drop into the upper 40°s to low 50°s for most WAFB neighborhoods.  And we’ve got highs in the 70°s on the forecast boards for Friday and Saturday, with some WAFB areas flirting with highs around 80° or so by Sunday!
Remember our “roller-coaster weather” comments yesterday?  Think about it, Metro Airport was in the low 70°s at lunchtime on Tuesday afternoon, then dropped to freezing by Wednesday morning -- a 40° swing in about 18 hours.  Then after this morning’s lows, we may be up around 80° by Sunday?
Heaters earlier this morning ... air-conditioners by the weekend!?!?
Increasing chances for rain will accompany the warm-up in the coming days.  We’ll throw in a slight chance of rain for Friday morning -- at 20% or less -- then post spotty rain chances (less than 20%) for Friday afternoon.  Saturday should be mainly-dry -- we’ll go with rain chances at 20% for Saturday afternoon -- but those percentages take a big jump up from late Sunday into early Monday.
A storm system will be building over the U.S. Plains on Saturday, which will pull a cold front through the lower Mississippi Valley by early Monday.  Given the warm temps and moist air mass in place over our viewing area ahead of the advancing system, scattered rains  -- showers and t-storms -- are expected by Sunday afternoon with rain becoming “likely” for Sunday evening and continuing through the overnight hours.
The exact timing and strength of the Sunday/Monday cold front remains uncertain at this point. In terms of the timing, the front may roll through quickly enough so that all of the rain will have ended before the start of Monday’s morning commute. As for the threat of severe weather, it’s too early to make concrete conclusions.  However, for now we’re thinking that we will have some thunderstorms accompanying the front but the primary severe threats will remain well to our north as the front slides through.
Early indicators from the NWS Weather Prediction Center show that WAFB neighborhoods can expect around 0.5” to 1.0” of rain with this event, with locally-higher totals under and along some of the paths of the bigger thunderstorms.  But then, hey, many of us could use a little rain in our backyards.
Cooler air will settle over the region following the frontal passage, but it won’t be anything like the polar chills we’ve seen the past two mornings.

Wednesday, November 13, 2013

Another Freeze Warning for Thursday Morning

By Jay Grymes & Steve Caparotta

Regardless of whether your neighborhood actually dipped to freezing or not this morning, there’s no denying that it was a very cold start to the day!  The thermometer dipped to 32° at BR’s Metro Airport and down to 31° at McComb (Pike Co.) Airport.  Fortunately, it was a very brief event and by 8AM just about everyone was back above 32°. 

The winds eased up a bit overnight and into the early morning, just enough to let most of the northern half of the viewing area experience a light freeze this morning.  Yet it didn’t get cold enough long enough to so much as ice-over the bird bath.  Based on WAFB Weather Watchers and on-line weather stations across the region, it looks like few communities on the south side of the I-10/12 corridor reached freezing this morning -- and if they did, it likely lasted for less than an hour.
Mainly sunny skies today helped to push afternoon temps climb into the mid to upper 50°s for most of us, but not everyone is finished with freezing temperatures just yet.  The National Weather Service (NWS) has posted another FREEZE WARNING for Thursday morning across portions of the viewing area.  Thursday’s FREEZE WARNING is limited to communities along and north of the I-10/12 and, unlike this morning’s WARNING, does not include Ascension and Iberville parishes this go-around.
 As Steve Caparotta noted Tuesday, during many of these multi-day freeze events, the ‘coldest’ morning is often the second morning -- after the chilling air mass has had time to settle over the area and after the winds have backed down.  With these Arctic and polar air masses, the winds often remain elevated for a number of hours after the front moves through.  Higher winds keep the lower levels of the atmosphere mixed, and that can reduce how quickly temperatures fall near the surface.
Why are winds important?  During these cold snaps -- and especially under clear skies -- the air becomes coldest right along the ground surface and actually gets warmer and warmer as you climb in elevation above the ground.  (Remember, the air temperature that we report from our stations is typically measured at roughly 4 to 5 feet above the ground.) Under light-wind to calm conditions, the air temperature at the lower levels of the atmosphere falls as the ground cools.  By comparison, under windier conditions, the warmer air from above is constantly being mixed downward, slowing the rate at which the air in the lowest levels can cool.
That brings us to our Thursday morning FREEZE WARNING. 
Tonight’s and tomorrow’s early morning winds will be lighter than what we saw for Wednesday morning, the skies will be clear once again, and Thursday will be the second day of the season’s first real chill -- that points to a good chance for colder start on Thursday morning compared to earlier this morning.
In fact, while the NWS has included fewer parishes in the FREEZE WARNING area for Thursday, they have extended the warning ‘window’ from midnight until 9AM (compared to 2AM to 9AM for Wednesday’s WARNING). 
What may limit just how cold it can get for Thursday morning is that the core of the coldest air has moved farther to the east today and will continue to do so overnight.  Based on that, we’re thinking that WAFB viewers well to the north and east of metro Baton Rouge can expect a slightly colder and longer-duration light freeze for Thursday morning.  For metro BR, it should be something similar to Wednesday’s brief freeze, while many viewers to the west of Baton Rouge may miss out on a Thursday freeze altogether. 
In the end, regardless of where you live in WAFB-land, Thursday’s chill will be nothing of serious concern -- just another very cold start to the day.
We’ll see some mainly-high clouds returning on Thursday, and we’ll bounce back into the 60°s for the afternoon highs.  Everyone will say ‘goodbye’ to the winter-like temperatures as the warming trend continues, delivering 70°s for Friday, Saturday and Sunday with morning lows in 60°s by the weekend.
We’ll also see rain chances increasing as we head towards the weekend as well, although the guidance remains mixed as to what to expect in terms of rain for Friday and the weekend.  A series of disturbances will keep the Gulf Coast weather unsettled for Friday and Saturday, with isolated showers in the forecast for both days and then “rain likely” for Sunday.
Also over the weekend, a storm system will be organizing over the Plains, with our next frontal passage expected during the day Monday.  And unlike Wednesday’s cold front, rain appears likely with Monday’s front.
So, we can consider this week as our first ride on the traditional cold-season weather roller coaster that we know so well!  And by the middle of next week, on the heels of Monday’s front, we’ll go through another big dip on the temperature coaster!

Tuesday, November 12, 2013

Freeze Warning for Wednesday Morning!

By Jay Grymes & Steve Caparotta

The FREEZE WARNING remains in effect as issued yesterday, with areas near and north of the I-10/12 corridor under the WARNING from 2:00am until 9:00am.

Officially, all of Southwestern Mississippi, the Florida Parishes and Ascension and Iberville parishes are included in the FREEZE WARNING, but only WAFB’s more northern viewers are looking at an event of more than a few hours.
Mississippi counties can expect lows in the upper 20°s by Wednesday morning, with freeze durations of 4 to possibly 6 hours in some places.  Most of the Florida Parishes can expect freezing temperatures for less than 4 hours, except for those living right up along the state line.  Neighborhoods along and just south of the interstate will likely see temps at or below 32° for a couple of hours.

Bottom line:  this is not a “pipe-wrapping” freeze.

A birdbath, a shallow puddle, maybe the dog’s outside water bowl -- those might freeze over here and there, but pipes along the sides of homes are going to be fine.  Those pipes will have more than enough heat stored in them to stave off this brief light freeze. 

But speaking of the dog bowl, make sure that outdoor pets have places to get out of the cold and the wind.  Northerly winds will remain in the 5-10 mph range overnight, occasionally sneaking into the ‘teens -- early morning 'wind chill' readings will likely dip into the mid 20°s for metro Baton Rouge and down into the low 20°s for much of SW Mississippi.

By the way, we are occasionally asked:  "Does ‘wind chill’ apply to my pipes?”  The answer is no. 
While high winds can allow objects to cool faster -- higher winds effectively pulling stored heat out of an object more quickly -- the object can’t get cooler than the air around it, no matter how fast the wind is blowing.  ‘Wind chill’ is calculated for humans only and is an ‘apparent’ temperature -- what it feels like.  And yes, even pets and livestock experience a ‘wind chill’ effect, although their coats offer protection that effectively lowers the chilling rate of high winds as compared to humans.

As for Wednesday morning, once the sun breaks the horizon, the day’s warm-up kicks-in with temps quickly rising above freezing.  Although Wednesday afternoon will stay cool-ish with highs only in the 50°s for many of us, most WAFB communities will be back in the 40°s by or before 10:00am.

We likely see another round of light freezes for parts of WAFBland near sunrise on Thursday morning, but for now at least it looks like Thursday’s wake-up lows may not be quite as low as what we'll see on Wednesday morning.  In addition,  durations for Thursday morning's light freezes -- where they do occur -- will be shorter as well.

And after Thursday morning, “Old Man Winter” retreats to the north. We’ll have 60°s for highs on Thursday afternoon, with 70°s for Friday and the weekend.  In fact, the Sunday outlook suggests many neighborhoods could be flirting with the 80°s.

In addition to a significant warm-up, we'll also see returning rain chances as we move into the weekend. The large 'dip' currently seen in the jet stream that is allowing cold air to plunge all the way to the Gulf Coast will quickly retreat to the north and be replaced by a southwesterly flow at the mid and upper-levels of the atmosphere. That southwest flow has two important implications for our weekend weather: 1) a significant warm-up, and 2) rains return to the forecast.

Scattered showers and t-storms are in the forecast each day from Friday through Sunday, but no single day looks like a washout. Keep your plans, but also make sure you have our free weather app for your smartphone to keep an eye on the rains. Best rain chances are expected on Monday in association with our next cold front.

Monday, November 11, 2013

Big Chill on the Way!

By Jay Grymes & Steve Caparotta

On this Veterans Day, we send a big “Thank You!” to those that have served and those serving still ...
We enjoyed a fine November weekend weatherwise ... and after a cool start, today was another in a string of fine fall days with highs reaching the mid to upper 70°s for most. 
While our forecast remains “dry” through most of the work week, there are some big changes in our weather just around the corner as a strong cold front continues to rapidly plunge southward, setting the stage for the coldest air mass of the season along the Gulf Coast by mid-week.
Tuesday will start off nice enough, with modest morning lows in the upper 40°s to low 50°s for most WAFB neighborhoods.  We’re expecting partly cloudy skies for the afternoon with highs for most WAFB neighborhoods reaching the upper 60°s to near 70° or so, but the advertised strong cold front will pass through the viewing area during the day.  Although winds tomorrow will likely be northerly even before the front arrives, you may recognize the mid-day frontal passage as winds pick-up in speed and dew point temperatures begin a steady fall.
Looking back at the autumn thus far, while temps through the first third of November have been slightly below-normal, monthly temperatures for both September and October averaged above-the-norm across the WAFB viewing area.  In fact, only a very few of our northernmost viewers have seen any early-morning lows in the 30°s thus far.  For Baton Rouge’s Metro Airport, the lowest reading this fall season has been 41°, while the autumn low so far for McComb (Pike County Airport) stands at 40°.
Why mention these lows?  Because for many, the arrival of our first real winter-like air mass tomorrow night will prompt the season’s first extensive use of home furnaces and supplemental heaters.  Remember to be extra cautious and watchful with that first use of home heating systems and please use extra special care with space heaters!  Space heaters and poorly-maintained home-heating systems are not all that far behind the kitchen in terms of the main culprits for house fires.

The cold, almost-Arctic blast arriving tomorrow will drop temps to or below freezing for much of the WAFB viewing area by Wednesday’s sunrise. That has prompted the National Weather Service to issue a Freeze Warning for much of the area. In addition, sustained northerly winds running in the 10-20 mph range will make it feel even colder, with Wednesday wake-up wind chills in the 20°s!  What’s more, Wednesday will stay quite cool even into the afternoon, with highs only reaching the mid to upper 50°s for most WAFB neighborhoods along and north of the I-10/12 corridor.

So ... is this early for a freeze?  Well, yes!  A look at records for Baton Rouge’s Metro Airport shows that this will be the earliest freeze since the Fall of 1993!  In fact, based on the last 50 years or so, we can consider Thanksgiving Weekend as a good ballpark estimate for the average date for the first freeze for the Red Stick (based on records from BR’s Metro Airport) - - generally the last few days of November.  For McComb (Pike Co. Airport), however, we’re not that far ahead of the mark -- the first freeze for our SW Mississippi neighbors averages around mid-November, and the McComb Airport recording two October first-freezes in just the past six years.  That 50-mile distance north of the I-12 for McComb makes a huge difference.

Add in the fact that with our relatively mild autumn thus far, most of us may not be mentally prepared for a ‘big chill’ just yet.  Thankfully, we’re in luck -- because it may get cold, but the winter-like temps won’t last long at all.
After another morning flirt with a wake-up freeze on Thursday, the winds will come around from the southeast (“return flow”) and we’ll begin a modest warm-up with Thursday afternoon highs back into the 60°s for most of us.  Friday morning lows will be back up to near 50° for most, with highs on Friday back into the 70°s for the Capital City.
Heading into Friday and the weekend, not only will we be back to highs above 70° each of the three days but along with the mild temperatures comes better rain chances.  Admittedly, the picture is far from clear -- there’s still a lot of uncertainty as to the timing of those rains.  At least for now, we’re suggesting that you prepare for scattered, mainly-afternoon rains for Friday, with scattered-to-likely rains over the weekend.

Staying quiet in the Atlantic Basin with no pending threats for tropical development ...