Friday, May 31, 2013

Hurricane Season kicks-off on June 1st!

Now would be the time to review your personal, family and business 'Hurricane Plan' ... aer you ready?  Check out for some helpful suggestions.  Remember, the consensus among tropical weahter forecasters is that the 2013 season will be another 'busy' one ... and 1-in-3 'named' storms become Gulf storms.
Rain coverage today was somewhat limited as we expected, but that wasn’t good enough to keep Alex Box dry ... and the LSU Tigers had to deal with a rain-delay in the early afternoon during their NCAA Regional match-up with Jackson State. Today’s showers tended to be fairly quick movers, running form south-to-north at about 20-25 mph, which means that for most that did get rain, it didn’t last long nor did it amount to much.
The rains will taper-off this evening and we’ll go to partly cloudy skies into the evening and overnight.
Saturday morning will be on the muggy side, with just a couple of showers for the early morning. By the afternoon, we’ll see a repeat of Friday’s weather: in-and-out of the clouds, with passing showers and a few rumbles of thunder with temps climbing to 90° or more. We’re setting rain chances at about 30% for the afternoon -- so most of you stay dry -- with the temp and humidity combining to push the Heat Index (‘feels like temp’) into the mid 90°s.
We’re still expecting a cool front to slide through the state on Sunday, and that means better rain chances through the day -- for now, I’m thinking a 50% to 60% chance through the middle of Sunday. The good news is that it does look like Sunday’s front will continue to march to the east and southeast on Monday, allowing “drier” (less humid) continental air to filter into the lower Mississippi Valley for Monday afternoon into Tuesday. That doesn’t mean a big drop in the afternoon temps for those two days -- I’m still calling for highs around 90° -- but the afternoons won’t be oppressive thanks to the lower dew points.
Sadly, the “drier” air mass doesn’t last long and by Wednesday the humidity begins its return, with scattered rains returning to the forecast by Thursday and Friday.

Thursday, May 30, 2013

A Short Reprieve from the Rains?
The start of Hurricane Season is just two days away: are you Hurricane Ready? Have you got your “Game Plan?”
We’ve been keeping a watch on Barbara, the Eastern Pacific tropical system that was trying to work its way into the southwestern Gulf (Bay of Campeche). Fortunately, Barbara couldn’t survive the trip -- although ‘she’ picked the narrow strip of Mexico’s Isthmus of Tehuantepec, the interaction with the nearby high terrain and ‘her’ slow movement spelled “Goodbye” to Barbara -- and the National Hurricane Center has issued its last advisory on the system.
Around the WAFB viewing area, we did have a few showers and t-storms in the region today, but coverage was considerably lower than what we saw on Wednesday. And we expect a repeat of this drier pattern for Friday and probably Saturday as well. True, the air is moist enough, but the atmosphere is not quite as unstable as it was at mid-week, so there’s not quite as much opportunity for rising air to generate rain-making clouds. Still, we do expect a few afternoon showers and storms for Friday and Saturday -- we’re setting rain chances in the 20% to 30% range for both days.
A cool front will be getting better-organized in the Southern Plains by Saturday, with that front expected to reach northwestern Louisiana by Sunday morning. This boundary will provide a boost in atmospheric lift -- in other words, it should help get the rains and t-storms going on Sunday. For now, I’m thinking a 50-50 chance or better for rain in your backyard on Sunday afternoon and evening.
Our current guidance says the front slowly clears to the east on Monday, with a drier Canadian air mass filtering into the lower Mississippi Valley by Tuesday. Now don’t be thinking “cooler” -- in fact, with the drier air we should see fewer clouds, which means more solar heating. So look for highs in the low 90°s for next Tuesday and Wednesday, but we should feel a brief drop in the humidity.
Down the road, there is some hinting at another front approaching towards the end of next week.  We'll have to watch and see if that really pans out.

Tuesday, May 28, 2013

Summer Pattern Sets-in for the Week!
-- 28 May 2013
Don’t look for any cool fronts this week -- all of the nation’s frontal action will remain to our north and west into the weekend, at least. Along the Gulf Coast, we are locked into a summertime weather pattern now, with Gulf moisture and late May heat combining to make the afternoons uncomfortably warm and also fuel those typical afternoon showers and t-storms as we head deeper into the work week.

After our long-weekend of relatively “dry” air, today’s rain coverage remained rather limited. But that changes for the rest of the week as the atmosphere overhead “moistens up.”

A dome of surface high pressure is located just off the Atlantic Coast with low pressure sitting just east of the Rockies. That puts us in the middle of an east-to-west pressure gradient, which will mean a general southeasterly flow over the WAFB viewing area for the coming days. That means a steady flow off the Gulf with the regional atmospheric moisture climbing as the week progresses.

This morning’s low of 67° will likely be the “coolest” morning start that we’ll see for some time. Mornings will be rather muggy for the rest of the week and right into the weekend, with sun-up temps running at or even above 70° for the Red Stick -- a signal of a moist air mass in place. By the mid to late afternoons, temps will have climbed into the upper 80°s to low 90°s for most WAFB neighborhoods, with clouds building through the afternoon thanks to the warm and unstable air mass. That means scattered afternoon and early evening thundershowers just about every day for the rest of the week.

The NWS Weather Prediction Center (WPC) maintains our summer-like days into the weekend, but also is suggesting that a cool front could work its way through the Bayou State on Sunday. For the time being, the extended models don’t seem to be showing any real “cool down” with this proposed front -- we’ll watch as the week progresses to see of the computer models offer any heat relief down the road.

We continue with Hurricane Preparedness Week -- today’s topic is wind.

Most of us are well aware of the Saffir-Simpson Scale, with 5 categories for hurricanes based on sustained maximum winds. Louisiana is no stranger to hurricanes, having been impacted by more than three dozen since 1900. And of those, 14 were major hurricanes (Category 3-5) at landfall!


But it’s important to realize that tropical storm force winds -- ranging from 39 to 73 mph -- are more than sufficient to produce damage, especially when they persist for extended runs of hours.

In addition, hurricanes can generate destructive and deadly tornadoes, a serious threat that is often overlooked. As an example, the NWS confirmed more than 30 tornado touchdowns in Louisiana during 2008 thanks to Gustav and Ike.

Monday, May 27, 2013

Increasing Rain Chances This Week

By Jay Grymes & Steve Caparotta

We enjoyed somewhat of a break from our usual muggy weather for part of the weekend, but humidity is quickly making a comeback and we’ll see a return of our typical late-May ‘muggies’ through the week! That will translate into warmer morning starts near 70° and less comfortable afternoons as highs top out in the upper 80°s.

Titan9 Doppler Radar has only picked up on a few spotty showers and t-storms the last couple of days, but we’re also expecting increasing rain chances this week. Rain coverage should remain pretty limited on Tuesday – less than 20% -- but better rain chances are expected the remainder of the week. We’ll put at least a 50/50 chance of wet weather in the forecast on Wednesday, with scattered, mainly afternoon showers and t-storms each day from Thursday into the weekend.

So why are we looking for increased rain chances? Believe it or not, a lot of it will have to do will a large plume of moisture originating in the western Caribbean. Clockwise flow around high pressure (the ‘Bermuda High’) in the western Atlantic will transport this source of deep tropical moisture all the way through the Gulf and into our vicinity later this week. Increased moisture, combined with temps in the upper 80°s to near 90°, should set the stage for scattered showers and t-storms for the second half of the week into the weekend.

And a final note…with the official start of Hurricane Season looming on Saturday, FEMA and NOAA have declared this week as “National Hurricane Preparedness Week”. Today’s focus is the threat of storm surge – one that we are all too familiar with here in south Louisiana.

We’re all aware of the large storm surges associated with hurricanes like Camille, Katrina, and Rita, but did you know 2012’s Isaac produced a storm surge topping 10 feet in parts of Plaquemines and St. Bernard parishes? And it also produced flooding that some had never seen in parts of St. John, St. James and Ascension parishes. This from what was ‘only’ a Category 1 hurricane. Isaac is the perfect example of why storm surge has been removed from the Saffir-Simpson scale used to rank hurricanes. The Saffir-Simpson scale was originally designed as a ‘wind’ scale and really does a poor job of conveying the storm surge threat from a given storm. While Isaac only produced Category 1 winds, it was a larger-than-average storm that was moving very slowly near and after landfall in Louisiana – two factors that led to an enhanced storm surge. So, if you live in a flood prone area, we encourage you to avoid simply thinking of storms in terms of their Saffir-Simpson categories and to pay attention to forecasts for water level rises in your area. This will give you a much better idea of potential impacts.

Friday, May 24, 2013

Warm, Less Humid This Weekend

By Jay Grymes & Steve Caparotta

We’ll keep a very slight chance of rain on the board into the evening, but it looks like the weak ‘backdoor’ front we’ve been waiting this week has eased its way through most of the viewing area.  Light, variable winds at Metro Airport will become light northeasterly and then easterly later this evening and overnight, signaling that the front has drifted south and southwest of metro Baton Rouge.

With the frontal passage and wind shift we’ll also enjoy a nice drop in humidity.  Dew points that began the day in the upper 60°s will drop into the low 60°s by Saturday morning and could even make their way down into the upper 50°s by Saturday afternoon for some WAFB areas.  That’s in the “very comfortable” range for dew point temps: not unheard of during late May but somewhat uncommon for this time of year.

Our latest set of model guidance suggests that we can expect dew points to remain in the 60° to 64° range across metro Baton Rouge through Sunday and into at least the first half of Monday before “return flow” (winds off the Gulf) starts to moisten-up the air once again.

So it’s two thumbs-up for the 3-day Memorial Day weekend -- the “unofficial” start to the summer season.  Yes, afternoon highs will still reach the upper 80°s for most WAFB neighborhoods on Saturday, Sunday and Monday, but the reduced humidity will mean comfortable mornings (at least by late May standards).  In addition, the “dry” air means that rain chances for all three days will be about as close to “zilch” as we can expect for this time of year!

Three great “outdoor” days -- just remember the water and the sunscreen and watch the kids and the elderly for sign of heat stress if they stay outside for long stretches at a time.

Sadly, the “dry” air will be gone before the middle of next week.  We close out the last days of May (Wednesday thru Friday) with a more typical south Louisiana summertime pattern: morning lows in the upper 60°s to low 70°s across the viewing area with afternoon highs in the upper 80°s to around 90° and isolated-to-possibly-scattered afternoon and early evening t-showers.  But then that is the way it is supposed to be.

And when you have a free moment, take time to remember the purpose of this federal holiday: Memorial Day is for recognizing and honoring those who died while serving in the U.S. Armed Forces.

Thursday, May 23, 2013

Lower Humidity on the Way!

By Jay Grymes & Steve Caparotta

There were some pockets of rather dense fog this morning, but not enough to prompt the NWS to issue an advisory -- the same will likely be true for Friday morning.

A few t-storms popped up late this afternoon – producing frequent lightning and heavy rainfall – but most of us have remained dry, with highs climbing up to around 90° for many WAFB neighborhoods. That too may be repeated for Friday afternoon, although we suspect that showers for Friday afternoon will be mainly confined to the coastal areas.

As we’ve mentioned through the week, we expect a “backdoor” cool front to work through the viewing area during the morning and mid-day hours on Friday. 

What’s a “backdoor” cool front? It’s a term for a front that slides into the area from the north or even northeast rather than the normal approach from the west or northwest.

Our “backdoor” front won’t have much of an impact on afternoon temps, but it will deliver a “drier” (less humid) air mass, which will mean a drop in the daytime humidity and morning starts in the low 60°s for Saturday and Sunday morning.

We’re headed into the “extended” Memorial Day Weekend - - considered by many to be the unofficial kick-off to the summer season. And the forecast for the entire weekend is a great one no matter where you plan to be in the Gulf South region. Whether it’s the coastal beaches, chasing the Tigers in Hoover, or just an afternoon in the backyard, the forecast everywhere is not only a rain-free 3-day weekend, but the northeasterly flow thanks to Friday’s cool front will mean everyone gets a dose of the less-humid air mass.

But the “drier” air doesn’t last too long. Winds will begin to swing around on Sunday and by Tuesday we’ll be back to our more typical late May muggies. But even then, our forecast stays mainly dry for Tuesday and Wednesday, with just a 20% rain chance for Thursday.

And in case you don’t catch the news this evening, the NOAA tropical experts (from the National Hurricane Center and the Climate Prediction Center) issued there forecast for tropical weather activity in the Atlantic basin today. Their forecast offers no insight as to U.S. landfall threats, but does suggest that we will see another busy season with: 13 to 20 ‘named’ storms, 7 to 11 becoming hurricanes of which 3 to 6 would become ‘major’ hurricanes of Category 3 or higher.

Are you Hurricane Ready? Have your “Game Plan?”

Wednesday, May 22, 2013

Much Drier Next Couple of Days

By Jay Grymes & Steve Caparotta

Now that was a nasty way to start the day, with WAFB Traffic Center reporting more than 30 accidents in and around metro Baton Rouge during the morning commute thanks to the stormy weather.  But that wasn’t all that was a mess:  thunderstorm winds generated pockets of damage across the WAFB viewing area and Titan9 Doppler radar picked up indications of hail with the bigger storms.  Add to that some very active cloud-to-ground lighting and WAFB Weather Watchers reporting widespread 1” to 3” rain totals -- with some reports topping 4” for the day!

In case you are wondering: today’s storms were not a sign that the cool front has moved through -- the front remains to our north and will likely still be there into early Friday.

But we think we’re generally done with rain for the rest of the week.  We could see a spotty shower or two on Thursday and/or Friday afternoon, but the vast majority will stay dry for both days.  What we will see on Thursday and Friday is a return of Gulf heat and humidity, with afternoon highs on both days likely climbing back into the 90°s for many WAFB neighborhoods.

By Friday morning, however, the cool front currently to our north and northwest will “backdoor” its way through the WAFB viewing area (moving almost NE to SW).  As we mentioned in earlier discussions this week, we don’t expect a big drop in the afternoon temperatures as a result of the cool front’s passage, but we will feel a welcomed drop in humidity as the flow comes out of the NE and east for Friday into Saturday.  That should deliver morning lows for Saturday and Sunday in the low 60°s for the Red Stick, and even cooler north and east of metro BR -- quite a change after our recent run of sun-up temps in the 70°s!

By Sunday, the winds will have shifted back around from the SE, but we’ll stay dry for Sunday and Memorial Day (Monday).   Highs through the long weekend will be in the upper 80°s with mainly sunny days -- a great “unofficial” start to the summer.  Grab the sunscreen!

And for those of you headed to the Gulf Coast or maybe up to Hoover to catch the Tigers?  No weather problems to be found anywhere!

In fact, our forecast stays dry through Tuesday, with only a slight chance of rain for next Wednesday.

Tuesday, May 21, 2013

Better Rain Chances on Wednesday

By Jay Grymes & Steve Caparotta

The weather has remained active to our north and west, but as of 4PM we’ve seen nothing to compare with the severe outbreaks of the previous days.  So far, no confirmed tornadoes although there have been one or more reports of funnels spotted in East Texas.  Based on the daily reports from the NWS Storm Prediction Center (SPC), there is one cluster of wind reports in north-central Texas and a second zone of wind-damage reports extending from central Tennessee into southern and central Kentucky.

What has our attention this afternoon is the SPC’s area of “Moderate Threat” for severe weather that extends from southwest of Dallas to the east, capturing a large portion of northern Louisiana.  A “Slight Risk” extends southward into Alexandria -- with the threats in effect through the evening and overnight.  The main threats appear to be damaging winds and large hail, but we certainly cannot rule out tornadoes, as evidenced by the series of Tornado Watches in effect for portions of Texas, Louisiana, Arkansas, Mississippi and Tennessee.

By the way, the Moore, OK tornado was “upgraded” to an EF-5, the highest on the ‘Fujita Scale’ -- and the first EF-5 in the nation since 2011.  A quick look at the historical data back through 1950 shows that this storm is only the 8th F-5/EF-5 for that state ... and the 58th for the U.S. as a whole.  Louisiana has suffered only one F-5/EF-5 since 1950: a monster that began over Madison Parish in the northeastern portion of the state on the afternoon for February 21, 1971 and tracked into western Mississippi.  

As for our local weather, the heat is on!  Today’s highs were in and around 90° for much of the viewing area, and we expect more upper 80°s to near 90° readings for the coming days.  We’ve got the Gulf humidity in place, and a cool front that is serving as the storm trigger for the action to our north and northwest.

We’re going with 50-50 rain chances for Wednesday, and our in-house model is even suggesting that we could see a few showers and t-storms overnight tonight.  We don’t anticipate anything severe, but you’ll want to have the umbrella ready when you head out the door tomorrow morning.

Scattered showers and t-storms will remain possible through the day on Wednesday as a cool front to our north slowly sags southward in this direction. We’ll set rain chances around 50% and while we can’t rule out a strong storm or two, we don’t expect any widespread severe weather.

The chance for a few showers and t-storms will persist into Thursday as the cool front ever so slowly moves into the area. However, we still think there will be enough sunshine for highs to approach 90° in many locations.

Some good news for the Memorial Day weekend is that it looks like the cool front will sag to our south on Friday. While it may only shave a couple of degrees off of our afternoon highs, it will knock morning lows down into the low-mid 60°s and should also produce a noticeable reduction in humidity. The bottom line is that we’ll still be warm through the weekend, but with lower humidity, it should be much more tolerable outdoors.

We keep the forecast dry through the holiday weekend and through Memorial Day itself. In fact, it looks like mainly dry weather may continue through much of next week.  

Friday, May 17, 2013

Feeling Like Summer This Weekend!

By Jay Grymes & Steve Caparotta

As expected, you could feel that added humidity today: as a warning, it will feel even warmer over the coming weekend.

The good news is that the weekend should stay dry; the not-so-good news is that we’ll get a real “summertime feel” during the afternoons on both Saturday and Sunday. But then, we are into the latter half of the month of May -- it’s supposed to start getting that warm-and-muggy feel to the air.

The truth is, we’ve been spoiled so far this month. Daily temperatures have been below-normal for each of the past 14 days. We may have ended that trend today ... and our forecast through the weekend and all of next week calls for morning starts close to 70° and afternoon highs in the upper 80°s to near 90° -- numbers that are generally 1° to 2° above late May normals. In fact, don’t be surprised to see some WAFB neighborhoods hit 90° over the coming days.

Remember, as we head into summer, morning minimums are a rough “proxy” for the dew point temps, the measure of moisture (water vapor) in the air. Higher dew points mean higher humidity. With dew points in the mid to upper 60°s and afternoon temps climbing into the upper 80°s, we could see peak Heat Index numbers in the afternoons rising above 90°.

You’ll also note that our forecast is “mainly dry” over the next 5 to 7 days – just about rain-free over the weekend and only spotty-to-isolated rain chances in the forecast for next week.

Even the mid- and upper-levels of the atmosphere are hinting at a more summer-like structure. The nation’s active weather will remain to our north and northwest over the weekend and our computer guidance is showing the jet stream and its associated ridges and troughs staying to our north over the coming days. This northward contraction of the mid-latitude west-to-east flow in the atmosphere means that fronts and low-pressure systems are less likely to reach the Gulf Coast -- another summer weather-pattern signal.

So get ready for a very warm weekend. Just grab the sunscreen and the water bottle and enjoy!

Thursday, May 16, 2013

Heat, Humidity Continuing to Increase

By Jay Grymes & Steve Caparotta

Titan9 Doppler picked up a couple of showers during the morning drive today, and the afternoon has been another day with the viewing area in-and-out of the clouds. Titan9 also hinted at a few passing showers north and northeast of the Baton Rouge metro area during the early to mid afternoon, but as of 4PM all is quiet in our region.

That’s not true to our northwest, where several parishes and a few Texas counties have been dealing with a ferocious looking thunderstorm cluster that has prompted a series of Tornado Warnings over the last couple of hours.

As we thought, Thursday turned out to be pretty dry. We’ll continue with passing clouds through the evening and overnight, but the low-level air just keeps getting “juicier” -- we expect dew point temperatures to stay in the upper 60°s overnight, which means that’s where the air temps will bottom out for our Friday morning low. Don’t be surprised to see a patch of two of fog in the morning, but not enough to be an issue for the morning commute.

We expect a sun/cloud mix for Friday afternoon, with a token 10% rain chance. But when we consider the elevated dew points accompanied by afternoon temps in the mid to upper 80°s, we’ll get a serious taste of summer.

That will be the cast through the weekend too. In fact, a few neighborhoods could hit the 90° mark over the weekend. But for now, we’re keeping rain out of the forecast for both Saturday and Sunday.
In the extended, we’ll be watching a cool front sagging to the south and southeast around mid-week. Yesterday our guidance hinted at the front moving through the viewing area on Wednesday afternoon or evening, but the latest projections from the NWS Weather Prediction Center now suggest that the front may stall to our north -- a common scenario for frontal systems as we head into summer.

On a different note, we’re still watching the Mississippi River. At 35.1 feet this morning, that puts the river at Baton Rouge just above flood stage (35.0 feet). The latest forecast calls for it to crest at 35.5feet this coming Monday -- less than one foot above “official” flood stage but still nine to ten feet below the levee tops and more than eight feet below the high water crest in the spring of 2011.

We did a little looking to see how unusual -- or just how common? -- a spring crest above flood stage is. Well, it is not unusual at all. Over the past 20 “extended” springs (Feb 1 and June 30), the Mississippi River at Baton Rouge has risen above flood stage at Baton Rouge during 13 of those springs, climbing to 40.0 feet or more during four of those events.

Wednesday, May 15, 2013

A Few Showers Possible Thursday & Friday

By Jay Grymes & Steve Caparotta

We started the day with some high level clouds, arriving a little earlier than expected.   Morning temps for the Red Stick and much of the WAFB viewing area did drop into the upper 50°s during the pre-dawn hours, making for a comfortable start to the day.

As the morning wore on, the clouds thinned a bit, leaving us with fair skies into the afternoon with highs climbing to the low to mid 80°s.  Winds slowly shifted through the day, swinging around to the south by the afternoon.  With the flow now coming off the Gulf, the added low-level moisture means rising dew point temps -- and an end to our morning temps in the 50°s.

We continue to carry a slight chance -- 20% or less -- for afternoon rain on Thursday as an upper-level wave slides across Texas and passes to our north.  We expect to be in and out of the clouds on Thursday, with afternoon highs in the low to mid 80°s.  You will also notice a rise in the humidity through the day if you spend any time outdoors.

Our outlook for Friday through Sunday is a mainly-dry one.  We’ll go with a token 10% rain chance for Friday afternoon, but staying dry through the weekend as a broad ridge of high pressure settles centered over the eastern two-thirds of the U.S. and controls our weather.  The bog local weather story through the weekend will be the “almost summer” feel to the air -- highs in the upper 80°s with dew points in the mid to upper 60°s -- that means mid to late afternoon Heat Index numbers rising to around 90° or so.

The extended outlook into the first half of next week calls for a slow increase in rain chances by Tuesday into Wednesday as the central Gulf Coast awaits the arrival of our next cool front.  And keep in mind that from a climatological perspective, we’re fast approaching the normal end of the “spring frontal weather” season for south Louisiana.  Frontal passages will become less frequent -- and less important in terms of rainfall -- over the next few weeks as we shift to a sub-tropical summer-season pattern.

Did you hear that?  It’s Hurricane Season, through the front gate and on the way to our front door!

Tuesday, May 14, 2013

Increasing Clouds, Humidity Next Couple of Days

By Jay Grymes & Steve Caparotta

Today was another beauty, although a tad warmer than Monday.  And as we mentioned yesterday, today’s humidity began a slow upward climb and will continue to do so into Wednesday as a southerly flow brings more low-level Gulf moisture into the viewing area.

The dome of surface high pressure that has given us these three great spring days will continue to slide eastward, helping to strengthen the inbound flow off the Gulf.  At the same time, a broad upper-level ridge extends over most of the western half of the U.S., bringing unusually warm conditions to the Central and Northern Plains for yet another day.

We expect the upper-level ridge to continue to ease its way to the east: it should be centered over the Mississippi Valley for Friday and Saturday.   As you recall, upper-level ridging typically brings warm and mainly-dry weather for those under it.

The only fly in the weather ointment for us is that same upper-level low that has been sitting over northern Mexico and the Gulf of California during the past several days.  That low is beginning to “open-up,” meaning that it is losing its “closed” low structure and will come under the influence of the larger-scale mid- and upper-level atmospheric steering.   In fact, we’re already seeing some slow movement to the east-northeast today.

We expect the upper low to move across the Southern Plains and stay to our north on Wednesday and Thursday.  That low is a contributing component to our Wednesday afternoon forecast, which calls for increasing clouds and a sun/cloud mix for most of the WAFB viewing area for Wednesday afternoon and evening.  In fact, the low will get just close enough to give us a slight chance of rain on Thursday.  At this point, we’re staying with rain chances at 20% or less: that most of us stay dry, but we could see a few blips on Doppler radar.

Once that upper “wave” moves to the east, the broader upper-level ridge will take charge of our local weather.  Combine that upper ridge with a steady south-to-southeast flow for Friday, Saturday and Sunday and you have the makings of some dry but very warm days.  Highs will climb into the upper 80°s for many WAFB neighborhoods by week’s end and through the weekend -- factor in some Gulf humidity (dew points in the mid to upper 60°s) and you’ve got afternoons that will feel almost summer-like.

But then it is mid-May, so the summer feel is just around the corner!

Monday, May 13, 2013

Great Weather Continues Tuesday

By Jay Grymes & Steve Caparotta

Well, there’s certainly not much to complain about in this week’s forecast.

High pressure will be in charge for the next several days, leading to lots of sunshine and a warming trend through the week.  After lows in the upper 40°s to low 50°s earlier today for WAFB neighborhoods, highs climbed to near 80° or so across the WAFB viewing area. 

Look for the winds to swing around to the southwest and south tonight and tomorrow, resulting in a slow-but-steady return of Gulf humidity.  We’ll get one more ‘cool’ night with lows slipping to the low 50°s by Tuesday morning for the Red Stick, but the southerly flow and increased surface moisture will keep lows in the upper 50°s to lower 60°s for Wednesday’s sunrise.  And note that our forecast has lows in the mid to upper 60°s for the rest of the week, a hint for some rather muggy days ahead.

While our mid-week forecast is a mainly-dry one, we do expect to see a decent dose of clouds from latter half of Wednesday into Thursday.  Late last week we mentioned the cut-off low (an “upper-level” low) over the Gulf of California; the latest satellite imagery shows it is still there.  That upper low will “open up” and begin moving to the east-northeast as it is caught in the mid-latitude flow.  It won’t have sufficient energy to be a serious storm-maker for us but it is likely to create a decent amount of cloud-cover for us as it passes to our north.

Highs will be in the 80°s through the week.  Look for low to mid 80°s for Tuesday through Friday with upper 80°s expected for many WAFB communities by the weekend.  In fact, the coming weekend will have an “almost-summer”  feel to the air with some WAFB neighborhoods may get awfully close to 90° during the afternoons!

Friday, May 10, 2013

Flash Flood Watch Continues Through Saturday

By Jay Grymes & Steve Caparotta

Boy, was that a tough way to start off a Friday!  We opened the morning with a Thunderstorm Watch and a series of T-Storm Warnings across the viewing area.  The active weather was accompanied by hyper-active cloud-to-ground lightning as the main clusters of storms passed by, with localized rains of as much as 4” to 5” to 6” to end the work week.

And here at 5PM, we’re still hearing thunder at the studio, the rain continues to fall and there is still more rain on the way between now and Saturday afternoon.
In addition, we’re still waiting on the main cold front to slide by - - that is expected early tomorrow.  But it’s not just the cold front we’ve got to monitor: mid/upper-air disturbances riding through the atmosphere are spawning the period of  heavy rains and t-storms.  The first cluster produced the morning’s severe weather outbreak and we’ve just seen a second round of storms as the second disturbance marches from west to east across south Louisiana.
We’ve got another disturbance over Texas that appears headed our way.  We expect it to arrive early Saturday, delivering another round of locally-heavy rain and storms.
The GFS forecast model is showing an upper-level trough to our west that will leave a “cut-off” low over the Bay of California.  The main upper trough will swing to the east and help clear things out for Mother’s Day and leave us with a great looking first half of the work week.  The cut-off low will linger to our west through the first days of next week, then get picked-up by the upper-level westerlies and track eastward on Wednesday and Thursday, giving us modest rain chances on Thursday as it slides by.

Wishing Moms everywhere an early Happy Mother’s Day!!

Wednesday, May 8, 2013

Mainly Dry Thursday, Rain for the Weekend

By Jay Grymes & Steve Caparotta

As we’ve mentioned all week, we’re back to highs in the 80°s for the rest of the work week and you’ve likely felt the slow climb in the afternoon humidity.  We think you’ll really feel the humidity on Thursday afternoon, with dew points expected to be back in the 60°s thanks to the southerly flow.

Plan on a mostly cloudy Thursday, but it stays mainly dry (a spotty shower is not out of the question) through the day.

We’re still watching the evolution of our next rainmaker over the Southern Plains.  As expected, a surface low is getting better defined as it spins near the Texas Panhandle.  It will slowly track east-northeast over the coming days, with a trailing cold front extending to the southwest of the low into Texas.  While that front will be slow to get into our area, the atmosphere will become increasingly moist and unstable well ahead of the front.  Add in a series of west-to-east traveling disturbances at the mid/upper levels, and we’ve got the set-up for rains long before the front moves through.

Yesterday we were talking about a 40% to 50% rain chance by Friday afternoon -- as of this afternoon, we’re now thinking 60% to even 70% may be a better estimate for Friday afternoon and evening.  What’s more, we’re tossing in a token chance of rain (say, 20%) for Friday morning -- not what our “9 News This Morning” crew wants to hear as they get ready to set-up shop in French Settlement for their Friday Road Show!

The current timing for the advancing cold front still has it over far northern and western Louisiana on Saturday morning with a second low along the boundary finally approaching the WAFB viewing area late in the day.  Hopefully the front continues to the east and southeast and moves out over the northern Gulf during the early morning hours on Sunday.  

As we noted yesterday, the NWS Weather Prediction Center (WPC) also has a second, reinforcing Canadian front sliding through the area during the day on Sunday.  We’re keeping a 30% rain chance in the forecast for Sunday morning, but still counting on some afternoon improvements to salvage the latter half of Mother’s Day.

In the extended outlook, the first half of next week -- Monday, Tuesday and Wednesday -- looks dry, with highs each day in the 80°s.

Tuesday, May 7, 2013

Rain Returns by Friday
-- 7 May 2013

The chilly start to the month of May has ended as we can expect highs in the 80°s each day this week. Mind you, the outlook for the rest of the month is leaning towards a near-normal to cool May ... but normal May afternoon temps for the remainder of the month are in the mid to upper 80°s, so cooler-than-normal weather will be welcomed. Not only would most of us enjoy a delay in the onset of Louisiana summer heat, but who would complain about a delay in those ‘fat’ A/C bills?

The morning clouds were a little thicker than I expected -- the disturbance that was over East Texas on Monday evening held together sufficiently to deliver the mid-level cloud deck. But all in all, it was a nice Tuesday with highs in the low 80°s and dew point temperatures remaining in the comfortable 50°s.

Winds will start to swing around to the southeast by Wednesday afternoon (if not before), meaning a return of low-level Gulf moisture to our area for the rest of the work week. We’ll stay with fair to partly-cloudy skies on Wednesday with a morning low in the upper 50°s and a mild afternoon in the low to mid 80°s. By Thursday, you’ll start to feel the increasing moisture -- not becoming uncomfortable but a noticeable rise in the humidity as dew points climb into the 60°s.

A storm system will really start coming together over the Southern Plains (around the Texas Panhandle region) during Wednesday and Thursday. Right now, this storm system looks like a slow mover through Friday, but that means it will make a mess of at least a part of the coming weekend. We’ll keep the forecast “dry” for Wednesday and Thursday, with rain chances returning during the latter half of the day on Friday and extending through Saturday.
The latest NWS Weather Prediction Center (WPC) projections for this Plains storm have the surface low over northeastern Oklahoma by Friday morning with a trailing cold front extending back into central and western Texas. Although the front will still be well to our west on Friday afternoon and evening, the atmosphere will be sufficiently moist and unstable (the”warm sector” ahead of the front) for sunshine and daytime heating to get scattered showers and storms going -- set Friday PM rain chances at 30% to 40%.

The WPC forecast has the cold front over northwestern Louisiana on Saturday morning, sweeping through the Bayou State during the day -- showers and t-storms appear likely through the day and into the evening. In addition, the WPC forecast includes a secondary reinforcing cold front right on the heels of Saturday’s front, sliding from north-to-south and dissipating over south Louisiana on Sunday.

While there is no clear indication of a severe weather threat with this weekend’s two fronts -- well, not yet anyway -- we’ll be on-guard for that potential. Spring cold fronts are among the most likely to generate severe weather.

Sunday’s forecast is still a bit up in the air: for now, I’m expecting Saturday’s front (the first of the weekend pair) to use up the moisture and storm “energy” over the central Gulf Coast region. I could see some “backside” (post-frontal) rains extending into early Sunday, but these will be associated with the first cold front. I think that Sunday’s dissipating front will simply add another dose of dry, Canadian air to the area, but do little to add to the weekend rains.
It is interesting to note that at least one computer model does not seem impressed by the Canadian air mass behind the weekend’s double-barrel frontal passages -- the latest GFS model output fails to cool things down much at all for Sunday or Monday. We’ll see how that pans out into early next week. But for now, at least, the early part of next week looks good.

Hmmm ... May 7th: hard to believe that Hurricane Season is just over three weeks away!

Monday, May 6, 2013

Warming Up This Week...

By Jay Grymes & Steve Caparotta

If you like it cool in the spring, then you MUST be a happy camper!

We set two new records lows over the past few days -- on Friday and Saturday -- with Saturday’s low of 40° tying the Capital City’s all-time record low for any day in May! But that’s not all: Sunday’s high of 65° was the lowest high temperature ever for Baton Rouge on the 5th of May.

We did a little review of the last five days, then added in today’s numbers plus our forecasted high and low for Tuesday. For these first 7 days of May, we come up with a 7-day average temperature of 63° -- 10° below the ‘normal’ 7-day average of 73° for the first 7 days of May. In fact, based on daily data back to 1930, this will be the ‘chilliest’ first 7 days of May ever for the Red Stick. The prior “chilliest’ first 7 days of May was set in 1945 and was nearly 2° ‘warmer’ than what we’ve calculated for this May’s start!

Quite often, chilly in the spring comes with ‘damp,’ but not so this week. Our forecast keeps things mainly dry through Thursday. You’ll also notice a warm-up for the coming days, with 80°s on the afternoon boards for the rest of the week.

Surface high pressure will linger over the northern Gulf through Wednesday, then slide east towards Florida by Thursday. Between Thursday and Friday, a low pressure system will develop over the Southern Plains in the Texas Panhandle region with that system generating a cold front that will head east.

The strengthening front should reach northern and western Louisiana by early Saturday. Expect scattered showers and storms developing in the warm sector (ahead of the front) during the latter half of the day on Friday, with the main rain arriving in the WAFB viewing area on Saturday. Our current guidance suggests that the rains could linger into the first half of the day Sunday, with clearing skies during the latter half of Sunday leaving us with a good-looking fair weather Monday.

Friday, May 3, 2013

Record Lows Likely Saturday Morning!

By Jay Grymes & Steve Caparotta

As we expected, the front moved through metro Baton Rouge during the early morning, making it a wet commute for many.  The rains ended by or before 9AM for most WAFB neighborhoods (a little later for our easternmost viewers) but the clouds and brisk northwesterly winds kept the better part of the day uncomfortably cool, especially by May standards. 
As we head into the afternoon, satellite imagery is showing that the “clearing line” for the clouds was advancing slowly eastward.  Although the Capital City likely will see at least a little sunshine before sunset, temps in the 50°s and brisk winds for the afternoon and early evening will mean a chilly downtown “Live After Five.”  So go ahead and head downtown to enjoy “U4ria” ... just be sure to dress for it!
The winds will subside as we head into the late night -- add in clear skies and the cold-and-dry Canadian air mass -- and we’ve got the ingredients for a record low to start Saturday morning!  We’re posting a forecast low of 41° for Baton Rouge for Saturday’s sunrise: the current record for May 3rd is 43°.

The good weather news is that you can expect lots of sunshine for the weekend.  In fact, we are done with rain for a nice, long stretch of days.  Highs on Saturday will climb into the low 70°s, with a reinforcing surge of dry, continental air working into the lower Mississippi Valley late Saturday into early Sunday. 
Sunday -- May 5th, Cinco de Mayo -- will start off cold again, with morning lows in the mid to upper 40°s.  That means that we could make a run at Sunday’s record low also: 45°, set in 1954.  This second surge of cool and dry air will also keep highs around 70° for Sunday -- not bad by any means, but well below early May norms (low 80°s).
After the weekend, we’ll see a steady warming trend with afternoon highs back in the low 80°s by mid-week.  In the extended, the models are hinting at scattered rains returning by next Friday with decent rain chances in the outlook for next weekend.

But let’s leave the worry about next weekend for next week ... make plans and set aside some time to enjoy THIS weekend’s nice weather!

Thursday, May 2, 2013

Flash Flood Watch Extended into Friday Morning

By Jay Grymes & Steve Caparotta

Although we did see some large rainfall bull’s eyes across the WAFB viewing area over this run of rain days, some neighborhoods have seen very little thus far.  In the end, flooding concerns so far have been minimized in our region.
Still, the NWS not only has a regional FLASH FLOOD WATCH in effect, but has extended it until 7:00am tomorrow.

While we are maintaining good rain chances (50% to 60%) for the viewing area through this evening, overnight and into Friday morning, we believe that the threat for heavy rains -- even more localized bull’s eyes like we’ve seen the past day or so -- is minimal.  We’re expecting mostly light to moderate showers over the next 12 to 18 hours.  True, there could be a thunderstorm or two between now and early Friday, but we think those will be few and far between for the WAFB viewing area.
That pesky upper-level low that has been a three-day threat to be a big rainmaker for the WAFB neighborhoods is now to our southeast and will continue to drift away from us.  Even with some radar estimates of 2” to 4” over the past few days, many of us will see less than 1” of rain for the entire multi-day event.  It’s been a far different story well to our east, however, where rains pounded parts of coastal Mississippi, southern Alabama and the western end of the Florida Panhandle.  Latest radar estimates along that portion of the Gulf Coast suggest widespread rains of 4” to 8”, with some pockets of double-digit totals.

We still have to await the passage of our next cold front, which will occur during the early hours Friday morning.  Rains should end as the front slides by, but clouds will linger into the afternoon.  The other thing you will certainly notice is the much, much cooler air mass that moves in: morning temps will be in the 50°s but most of us will be lucky to make it into the low to mid 60°s for Friday afternoon.  It looks like it will be rather breezy for much of Friday as well.
Given the Canadian air mass coming in behind Friday morning’s front, we are forecasting a record low for Saturday morning, with BR area temps falling to the low 40°s!  Temps should rebound in the afternoon, however, with highs on Saturday climbing back into the 70°s.  But the computer models are delivering mixed signals for Saturday’s forecast.  Our in-house RPM model is suggesting that wrap-around clouds could even generate some light rains over the region!  But our other two key models offer much better outlooks for both Saturday and Sunday.

For the time being, at least, we’ll go with a fair-weather forecast for Saturday followed by a good looking Sunday.