Monday, November 24, 2014

Cool & Dry Week Ahead

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- stays cool and dry for Thanksgiving week
- warmer but still dry for the upcoming weekend

There’s not a lot to chat about, so we’ll keep this short …

We enjoyed a nice autumn day today: started the day in the upper 50°s and saw temperatures climb into the upper 60°s across the metro area under a mainly sunny skies -- just a few, thin cirrus clouds. As expected, a “dry” cold front moved through the region earlier in the day, delivering a less-humid air mass. A substantial cool-down begins this evening with local conditions remaining dry and pleasantly cool through the rest of the week.

We’ll have a real Louisiana autumn feel for the Thanksgiving week with temps running just a little below late-November norms through Friday. The weather cooperates nicely for those taking a little time off and for the school kids that get to enjoy an extended break.

After a Baton Rouge morning start in the low 40°s for Tuesday, our forecast calls for mostly cloudy skies for the afternoon. Just a weak disturbance making a fly-by and not enough moisture to produce any rain; we’re expecting highs on Tuesday in the upper 50°s to near 60° for the Red Stick.

Wednesday morning is shaping up to be the coldest morning this week with lows in the mid to upper 30°s. We don’t expect any significant freezes, although one or two of those usual “cold spots” to the north and east of metro Baton Rouge -- especially north of the LA/MS state line -- might briefly dip to near 32°.

We’ll keep mainly-sunny weather on the forecast board for Wednesday, Thursday and Friday with highs for all three days in the mid to upper 60°s for the Capital City. Yes, it’s looking good for the holiday gatherings on Thanksgiving Thursday and for those bargain hunters as we head into Black Friday and the weekend.

Even the weekend stays dry the way things look right now, although it gets warmer. We’re thinking 70°s for highs on Saturday and Sunday across just about the entire viewing area.

Thursday, November 20, 2014

Strong Storms Possible This Weekend

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- warming trend into the weekend
- “SLIGHT RISK” for severe weather late Saturday

It turned a bit chillier this morning than we had expected, with Metro Airport (BTR) and McComb (MCB) both slipping to 37° and Hammond’s Airport (HDC) dropping to 34°. A handful of area Weather Watchers posted lows in the 33° to 36° range but we found no “freeze pockets” for the morning start. What’s more, the warm-up we’ve been chatting about kicked-in today as most WAFB communities saw highs in the upper 60°s to low 70°s -- something closer to the ‘normal’ high for this time of year.

The warming trend continues tonight into Friday, with morning lows in the upper 40°s and Friday afternoon highs returning to the low 70°s under partly cloudy skies. It will be occasionally breezy into Friday afternoon, but all in all it will be a nice November day and a great way to end the work week. 

The First Alert forecast calls for 70°s through the weekend and for Monday as well, with highs in some areas reaching the upper 70°s on Sunday. But the BIG weather story for the next few days is the developing stormy weather threat set for the latter half of Saturday into early Sunday morning. A storm system expected to gather strength over the Southern Plains on Saturday will get an energy boost from moist-and-mild Gulf air feeding into it as it marches to the east. 

Although the NWS Storm Prediction Center (SPC) currently centers the region of greatest severe-weather threat (“ENHANCED RISK”) across central and southeastern Texas, the entire WAFB viewing area is included under a “SLIGHT RISK” for severe weather from late Saturday into early Sunday. We’ll be on the lookout for an active squall line ahead of an advancing Pacific cold front with the main weather threats being damaging winds and isolated tornadoes for our area. 

In addition to the SPC’s severe weather potential on Saturday night, the NWS Weather Prediction Center (WPC) continues to call for area storm totals on the order of 1” to 2” with locally-higher totals. Rains of this magnitude will not be a serious flood threat but could produce another round of nuisance flooding in the typical spots, leave standing water in poorly-drained areas, and generate short-term headaches for area drivers.

Once the main line of action moves to our east early Sunday, the weather should steadily improve through the rest of the day. However, unlike what we would normally expect, a significant cool-down doesn’t begin until early next week. A second Pacific front will follow on the heels of Saturday’s system, so we won’t get the normal wind shift from the northwest. A southerly-to-southwesterly flow is likely to remain in place through Sunday, allowing for Sunday afternoon temps to reach the mid to upper 70°s for many of us.

That second front moves through the region on Monday morning: then the winds come around with a cooler-and-less-humid northwesterly flow that continues into mid-week. Look for morning lows on Tuesday in the upper 30°s to low 40°s with mid to upper 30°s for Wednesday morning.

At this point we aren’t expecting a significant freeze event for the viewing area next week, although we could see a brief, light freeze near and north of the LA/MS state line on Wednesday morning. What’s more, it looks like we stay rain-free from the latter half of Sunday right through Thanksgiving Thursday. Our extended outlook currently calls for a partly-cloudy and mild Thanksgiving Day. However, for those already making their shopping plans for ‘Black Friday,’ we think that the “to do” list may include carrying an umbrella.

Wednesday, November 19, 2014

Warming Trend Underway...

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- warming trend is underway, stays dry through Friday
- still watching for the potential for severe weather over the weekend

So this morning makes four morning freezes for the Capital City in just six days with this morning’s freeze lasting the longest (about 11 hours at Metro Airport) and being the coldest with a morning minimum of 27°. There will be no more of that for a while: in fact, some of the long-range guidance suggests that the Red Stick may not see another freeze before month’s end. 

Trivia fans: it has been a very chilly November thus far based on climate history. We looked back through November daily records since 1893 -- 122 Novembers -- and found that there have only been six prior Novembers with four or more freezes on or before November 19th. The last November with four or more freezes by the 19th was 1991, which also happens to tie 1951 with the most freezes (seven) by this date. And in terms of the average temperatures, November 2014 ranks among the ‘coldest’ Novembers on record (thru the 19th) with the ‘coldest’ November 1-19 period since 1997.

However, the winds have come around and are starting to bring mild Gulf air into the region. After that bone-chiller of a morning start, we’ve begun a steady warming trend that will continue through the weekend. Thursday morning will start in the upper 30°s to low 40°s for most WAFB neighborhoods with a Thursday afternoon high in the upper 60°s to near 70° under partly cloudy skies. We’ll stay partly cloudy for Friday with a high in the low 70°s for many, then warm into the low to mid 70°s by Saturday afternoon. Sunday could see some upper 70°s for daytime highs.

So the weather stays quiet through Friday as we watch the next upper-level trough swing towards us from the west and help energize a storm system into the weekend. The warm-and-moist Gulf air that takes us into the 70°s over the weekend will also fuel a potent low-pressure system that gets organized over the Southern Plains. 

Just how active the weather becomes across our viewing area from Saturday afternoon into the early hours of Sunday is still unclear but we suggest that you get prepared for some strong-to-severe storms. Regardless of the thunderstorm/tornado threat, this weekend’s system is shaping up to be a wet one, with early indications from the NWS Weather Prediction Center showing 1” to 3” or rain possible for the WAFB area.

Then once again, following the frontal weather over the weekend, temperatures drop back to below-normal next week, although we are currently keeping minimums above freezing through Thanksgiving.

Tuesday, November 18, 2014

Another Freeze Warning Tonight

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- another freeze for Wednesday morning
- warming trend for the rest of the week
- stormy weather possible for the weekend

Fool me once: shame on you … fool me twice: shame on me. But fool me three times, and we say, “Hey, what’s going on here?”

Yep -- we know -- our early morning temperature forecast was a bust! In fact, our forecast lows for each of the three recent morning freezes (last Friday and Saturday mornings plus earlier this morning) have all been too cold. Our guidance tools haven’t done well at all: one of the normally more-reliable models, the American GFS, has been calling for lows that have been as much as 3° to 6° too low. What’s more, we think it may be doing it again for tomorrow morning.

We remind you that last night we mentioned the potential that some high clouds and light winds might be enough to keep Baton Rouge in the upper 20°s … in the end, those clouds were considerably heavier than we had expected. As a result, the low didn’t drop below 30° for almost all WAFB communities and the freeze line barely extended south of the Capital City. 

While that’s good news for keeping the home a little warmer overnight and it means that freeze-protection efforts were more than adequate, being “too cold” with our forecast by 3° to 4° is a bit disappointing for us. And some of you may be grumbling about the preparations that you undertook that weren’t really necessary.

As a reminder: how do the clouds impact the falling temperatures? Essentially, they “capture and return” some of the heat lost at night from the ground and air near the surface. In reality, the ground gives off heat to the atmosphere at about the same rate whether we are under clear or cloudy skies. However, when clouds are present they re-direct some of that energy back towards the surface. In the end, under cloudy skies, the energy being “sent back” by the clouds means that the NET energy loss from the ground and low-level air is lower. A lower NET energy loss means a slower drop in air temperatures near the ground. 

In addition, just a little wind at night helps mix some of the slightly warmer air well above the ground down towards the surface. (Remember, during a routine afternoon, the air near the ground is warmer than the air aloft. But at night, the air near the ground usually becomes a little cooler than the air just a few tens of feet above the surface). Mixing the warmer air from above downward towards the ground further slows the “effective” cooling rate and can keep overnight and early morning temperatures a bit warmer than had there been no wind.

And late last night into early this morning, we had both: a decent cloud deck and a little wind.

So we’ll prepare for another freeze tonight into tomorrow morning, and we’ll go with a Wednesday morning low that proves colder than this morning’s minimum … but we won’t go as cold as the latest GFS and NAM models are suggesting. As of this afternoon, both models were calling for a Baton Rouge low of 25°. 

We are expecting mainly clear skies tonight. In addition, winds for most of the night should be near calm thanks to surface high pressure sitting right on top of us for much of the overnight hours (before shifting to the east early Wednesday). So, we’ll concede an overnight low in the upper 20°s but not the GFS’s mid 20°s.

After that, it’s “Goodbye freezes!” … probably for at least for the next 7 to 10 days or more.

A warming trend begins in earnest on Wednesday with Red Stick area highs expected around 60° or so under sunny skies. For Thursday, after a morning start around 40° we’ll plan for a sun/cloud mix with highs in the upper 60°s for metro BR. Then it’s back to the 70°s for Friday, Saturday and Sunday ... and possibly Monday too.

We’ll call for spotty showers on Friday afternoon with the weather becoming much more active as we head into mid-day Saturday. Our current guidance is suggesting that a fairly potent storm system will be sliding across the mid-Mississippi Valley through the weekend, promoting an active thunderstorm event across the Bayou State.

Our current thinking is that the weather could become very active from the latter half of Saturday into Sunday morning, with the potential for another round of severe weather that will be much like what we saw on Sunday evening. The NWS Weather Prediction Center is currently calling for widespread rains in excess of 2” between Saturday and early Monday for our viewing area and the NWS Storm Prediction Center is already calling for a 30% chance of severe storms this weekend over southeast Texas and southwest Louisiana. Given the 5-day window, that’s close enough to get our attention.

Monday, November 17, 2014

Hard Freeze Warning!

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- HARD FREEZE WARNING for the northern half of the viewing area tonight and Tuesday AM
- clear & cool for Tuesday
- another freeze and into the 20°s again for Wednesday morning  

Before we get to the forecast … we’ve received the Damage Survey from the National Weather Service that headed into Livingston Parish today to assess the tornado damage there last evening.  The survey team has confirmed what appear to be a pair of tornado touchdowns: (1) the first of EF-0 intensity extending a little over one mile between 7:45-7:50pm, about 6-7 miles southwest of Walker … and (2) a stretch of EF-0 to EF-1 damage over a nearly four-mile track  between 8:20-8:40pm to the north of Livingston.  Fortunately there were no injuries but “two distinct segments” (NWS quote) of damage.  Meanwhile, the big storms that rolled through dumped from 1” to more than 3” of rain around the area.

So the active weather is gone but you could probably tell by the weather’s behavior today that another blast of very cold air is on the way.  The skies steadily cleared through the afternoon but the winds have stayed up so far. 

The big question for tonight: “Just how cold?”, and the winds could be play a big role in determining the answer.  The National Weather Service has issued a HARD FREEZE WARNING for the northern half of the viewing area with a FREEZE WARNING in effect across the southern half of the region.

For now, we’re going with an overnight low of 27° for Baton Rouge -- of course, microclimate factors will result in local temperatures ranging from the mid 20°s to near 30° around the metro area.  Freeze durations north of the I-10/12 corridor could be from 6 hours along the interstate to as much as 10 hours or more near and north of the LA/MS state line.  Durations drop off south of the interstate corridor, with some sections of the coastal margins potentially dodging freezing temps.

We think the winds will die down overnight but two of our reliable models are suggesting some thin, high clouds moving in before dawn.  That should be just enough to keep us from a temperature free-fall overnight as indicated by one or two models which suggest low 20°s tonight for the Red Stick.

It sunshine for the next several days, but most of us will head back down into the 20°s for Wednesday morning -- in fact, Wednesday’s wake-up looks to be as cold or colder than Tuesday’s sun-up!  Neither day breaks a record low but this is still too early for this kind of stuff!  A quick look back at Baton Rouge records to 1930 shows that there have only been four other years when there were four or more freezes by November 20th -- we should match that with Wednesday morning’s freeze.

Staying cold?  No .. it’s back to the thermal roller coaster.  We’ll be back up around 60° for a high under sunny skies for Wednesday and then upper 60°s under partly cloudy skies for Thursday.  Our forecast gets even warmer for Friday and the weekend -- up to 70° or more -- but it comes with scattered rains on Friday and Saturday and another wet Sunday on the board.

Friday, November 14, 2014

Another Freeze Warning for Saturday AM

By Jay Grymes & Steve Caparotta
WAFB First Alert Quickcast:
- another FREEZE WARNING for tonight into Saturday morning
- warmer but very wet for Sunday into Monday
- another pair of freezes for next week
It was an extended freeze for most WAFB communities this morning although it didn’t get quite as cold as we have expected -- and we doubt that anyone is complaining about that!  Besides, we’ve got another chance for a freeze tonight into Saturday morning and it looks like it could get a degree or two colder for Saturday’s sunrise.
Metro Airport dipped below freezing before 2:00am earlier this morning and stayed at or below freezing until roughly 7:30am -- run of nearly six hours.  Even with today’s afternoon sunshine, some of us never got out of the 40°s today.  Now take today’s clear skies and add-in the expected light winds this evening and many of us will be set up for freezing temperatures by or before midnight.  That should let temps dip to or below this morning’s low readings by Saturday’s sunrise. With that in mind, the National Weather Service has once again posted a Freeze Warning.
So a little colder and a little longer in duration for the overnight freeze, but still not quite a “pipe wrapper.”  Look for temps at or below 32° for upwards of 6-9 hours in and around much of metro Baton Rouge, especially in those regular “cold pockets” where some of you live and always seem colder than the airport.  Expect an additional couple of hours of freezing temps for most areas north and east of the Capital City.
After that chiller of a start on Saturday, mainly sunny skies will be accompanied by a slow wind shift to the southeast by Saturday afternoon, bringing milder and slightly-more moist air off the Gulf.  We’re expecting a high on Saturday around 60° for the Red Stick -- still well-below normal for mid-November but quite a nice change compared to yesterday’s and today’s high temps. 
The change will also deliver a warmer overnight low for Saturday night into Sunday morning: we’re calling for Sunday morning lows in the mid to upper 40°s for metro BR.  At the same time, an upper-level system will tie-in with a low over the western Gulf, generating increasing clouds by Saturday evening with a very slight chance of rain before midnight.  The complex will make for a very wet Sunday: Sunday’s high gets into the 60°s with rains -- along with a thunderstorm or two -- continuing throughout the day.  The rains taper off on Monday but not before delivering from 1” to more than 2” of much-welcomed rain for many of us.
Skies clear late Monday into early Tuesday as our next Canadian air mass moves in ... and with that comes another pair of freezes for Tuesday and Wednesday morning!  So keep the heavy coats and comforters nearby!
Meanwhile, staying nice and quiet across the tropical Atlantic.​
Have a great weekend!

Thursday, November 13, 2014

Freeze Warning Tonight/Friday Morning!

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- FREEZE WARNING late tonight into Friday morning
- another morning freeze for Saturday
- substantial rains for Sunday and Monday

A damp, raw and ugly start to Thursday ... and while the skies stated clearing from west-to-east through the late afternoon and into the evening, it was too late to provide a sunshine-aided afternoon warm-up. In the end, most WAFB neighborhoods topped out in the mid to upper 40°s for their Thursday highs.

The clear skies, very dry air (low dewpoints) and north winds are a clear sign of what’s to come later tonight: a significant freeze event. We’re calling for lows in the mid to upper 20°s for metro Baton Rouge, with all but the extreme coastal areas experiencing at least a dash of freezing temperatures. Looks like we’ll threaten some record lows across the region.

We’ve talked about it a number of times this week: a “freeze” at mid-November is certainly “early” but not unprecedented. However, mid to upper 20°s for mid-November? Since 1893, we’ve only found four occurrences with lows of 26° or below this early in the fall for Baton Rouge.

Next question: how long do the freezing temperatures last? We’re looking at something on the order of 5 to 8 hours of temperatures at or below-freezing for the Red Stick. Areas north and east of Baton Rouge could see the freeze last as much as 7 to 9 hours or more; of course, the durations drop off as you head towards the coast.

So our assessment is that this is NOT going to be a “pipe-wrapper” freeze -- it doesn’t last long enough to be a serious threat. But don’t forget the pets … bring the tender plants under the carport … and check on family, friends and neighbors that might have problems staying warm tonight. And please be extra cautious with the portable heaters -- they are the cause of too many home fires at this time of year!

Sunshine on Friday will allow temps to climb to near 50° but that’s about it. Then it’s another overnight/early-morning freeze for Saturday. Into Saturday afternoon, fair skies and a windshift with the winds off the Gulf will help temperatures climb to around 60°.

A storm system over the U.S. Plains will be gathering steam over the weekend and that will deliver a wet Sunday and Monday for the WAFB region. We’re expecting widespread rains of 1” or more for the viewing area over the two days, with some of the guidance indicating 2” or more for the two-day event.

But once that system clears the state, it’s “Hello again!” to another chilly air mass with freezes expected again for Tuesday and Wednesday mornings.

So it looks like we get some much-needed rain over the next several days, but it comes with a chilly price.