Friday, December 28, 2012

Clearing, Much Cooler This Weekend

By Jay Grymes & Steve Caparotta

Today’s frontal passage shaped up to be a substantial rain-maker but severe weather was not a real issue. There were a few areas where wind gusts may have climbed into the 30+mph range in association with some of the passing afternoon t-storms, but all-in-all this was a much “gentler” frontal passage as compared to the storms of Christmas Day.

We’ve received some Weather Watcher reports of as much as 2” to 3” of rain today, with widespread rains of 1” to 2” for the frontal passage as indicated by regional radar estimates. (totals below are through 4-5 p.m. Friday)

The last of the rains -- to the east and southeast of metro Baton Rouge -- will wind down through the evening, but expect the clouds to linger into the overnight hours. Cooler air has already begun to filter into the WAFB viewing area and will continue to do so through the evening and tonight, with Saturday daybreak temps likely to dip into the upper 30°s to around 40° for neighborhoods along and north of the I-10/12 corridor.

We may still be under clouds early Saturday, but skies should clear through the morning, giving way to plenty of sunshine by the afternoon. But the cold, Canadian air mass will keep Saturday afternoon on the cool side: highs for metro BR will only reach the low 50°s, with some of the northern WAFB communities possibly not getting out of the 40°s.

The forecast for Sunday morning calls for a freeze for just about everyone from Ascension Parish northward -- and we may even see “hard freeze” conditions for SW Mississippi and parishes along the LA/MS state line! Thankfully, this will only be a one-day event, with temps climbing back into the 50°s under mostly sunny skies by Sunday afternoon - - and we say goodbye to freezes for the time being.

Temps will moderate for Monday and Tuesday, but rain moves back into the forecast with the warmer weather. A quick-moving storm system will track from the Southwest U.S. into the Southern Plains on Monday, then move into the lower Mississippi Valley by early Tuesday -- this could mean scattered rains for the area during the peak midnight festivities on New Year’s Eve.

The frontal system is then expected to slow and eventually stall near the Louisiana coast, then linger over the northern Gulf through Wednesday, possibly even early Thursday. The net effect: a “wet” start to 2013 beginning with a potentially stormy New Year’s Day, with rains continuing through Wednesday into Thursday.

Thursday, December 27, 2012

Storms Return on Friday

By Jay Grymes & Steve Caparotta

A stubborn cloud deck last night and through the morning not only kept our wake-up temps above freezing, but also slowed the mid-day warm-up. We finally saw the clouds clear by the early afternoon, with the temps at Metro Airport jumping from a chilly 40° at 11AM to 51° by 2PM -- not exactly warm, but at least a bit more pleasant than Wednesday!

Unfortunately, clouds have quickly returned this evening, with generally cloudy skies expected overnight. In fact, we expect to see temps show a slow, modest rise through the overnight and into dawn on Friday -- going from the upper 40°s to the low 50°s by daybreak. And along with the clouds, don’t be surprised to see a few blips on Titan9 Doppler radar by daybreak, especially for areas west of metro Baton Rouge.

A surface low developing along the Texas coast will get a boost from a mid/upper storm system currently over the Southwest U.S., and the two will combine to set the stage for a wet Friday afternoon and evening. T-storms are likely with this system, and a few are expected to become strong to severe storms: enough to prompt the NWS Storm Prediction Center to post a “SLIGHT RISK” for severe weather for southern Louisiana and SW Mississippi.

The main severe threats on Friday will be damaging straight-line winds, although an isolated tornado cannot be ruled out. For the details-minded readers, it looks like the severe-weather set-up on Friday will have sufficient shear in the atmosphere for the tornado threat, but instability (rapidly-rising moist air) may be lacking. By comparison, Friday’s stormy threat is far, far lower than what was in place on Christmas Day.

The model guidance is suggesting that most neighborhoods should expect rains on the order of 0.5” to 1.0”, with a few pockets possibly approaching 2.0” under the paths of the stronger t-storms. Localized street-flooding might be a problem, especially during the Friday evening commute, but like Christmas Day, we aren’t concerned about rises along area rivers and bayous.

The rains will move out overnight Friday into the pre-dawn hours of Saturday, with a good deal of sunshine expected for the weekend. But after highs in the 70°s for many on Friday, the weekend will be much cooler. Highs for both Saturday and Sunday will only reach the mid 50°s, and for now we’re posting a light freeze for the ‘Red Stick’ during Sunday’s daybreak.

Unfortunately, the way it looks right now, our area weather may not be very cooperative as we head into the New Year. New Year’s Day looks wet ... and we’ll continue to fine-tune the New Year’s Eve forecast in the coming days.

Thursday, December 20, 2012

  -- Jay Grymes
     WAFB Storm Team

Assuming that the Mayans got it wrong, our winter will "officially" begin tomorrow at 5:12am!

The storms rolled through earlier today, and thunderstorm winds did indeed create some problems across sections of southern Louisiana and SW Mississippi. And as expected, temps showed a slow fall throughout the day behind the frontal passage. In addition, the winds were quite brisk throughout much of the day.

Skies will stay clear tonight and the winds will die down once we get past sunset. With dew point temps expected to drop into the 20°s, most of us can expect a light freeze for our Friday morning wake-ups. The Friday morning freezes will be of short durations, so this is not a seriously threatening event -- not a pipe-wrapper and only a problem for the most delicate of plants. Moving the delicates under an overhang near the house or patio should do the trick.
Sunny skies will be the rule for Friday, but it does stay cool with highs topping out in the upper 50°s for metro Baton Rouge. Saturday looks good too, although once again we’ll start the day around the metro area with a brief, light wake-up freeze. But Saturday afternoon stays mainly sunny with highs back into the 60°s as the winds come back around from the southeast.
And by Sunday? Goodbye freezes, hello 70° once again! We’ll add in spotty showers for Sunday afternoon and evening, but all-in-all the next three days look good for the last-minute shoppers.
Okay ... now the not-so-good news: we’ve got scattered rains in the current outlook for Monday, Christmas Eve. 
And the bad news? As of now, rain appears likely for Christmas Day as the current guidance brings the next cold front through Louisiana. In fact, while there remains some wiggle room and uncertainty, early indicators are that the Christmas Day front may indeed be accompanied by some active-to-severe storms. We’ll be watching these developments closely in the coming days.

Wednesday, December 19, 2012

Strong Storms Possible Early Thursday

By Jay Grymes & Steve Caparotta

(Heads Up!  The December Solstice -- the “official” start of winter -- arrives at 5:12AM on Friday.)
The clouds were slow to build over the WAFB region today -- no complaints there, I’m sure! --  and the mild afternoon with highs in the upper 70°s may have left many wondering about the stormy forecast we’ve been chatting up for Thursday morning.
Yes, the rains and t-storms are still coming!  And it looks like it could be a real mess for the Thursday morning commute, with rains and t-storms.  Some of those t-storms could be on the strong side, and as we reported on Tuesday, most of the WAFB viewing area along and north of the I-10/12 corridor is included in a zone for a “Slight Risk” of severe weather by the NWS Storm Prediction Center.  The main severe-weather threat will be straight-line winds; thankfully, the tornado threat remains extremely low.

The other bit of good news is that the forecast still calls for this front to be a relatively “fast mover.”  The rains should end in the metro Baton Rouge area by mid-morning, with skies clearing by, if not before, lunch-time. (Rains end and skies clear later for areas south and east of BR.)
Thursday will be an “upside down” day temperature-wise.  Sunrise temps for many will be in the upper 60°s to near 70°, but once the front moves through, temps will begin a steady fall throughout the day.  Look for sunny skies by Thursday afternoon, but temps will be in the 50°s and gusty winds will give it an even cooler “feel.”  By the evening, many of us will be in the 40°s ... and by Friday morning, a good portion of the WAFB viewing area will be dealing with a light freeze!
Highs on Friday will top out in the upper 50°s for most of us, with another light freeze for Saturday morning.
Last-minute shoppers will be pleased to know that the weekend weather will be cooperative: mainly sunny with highs in the low 60°s for Saturday followed by a mild, partly cloudy Sunday with highs approaching 70°!

The weather on Monday and Tuesday may not do much for those looking outdoors for some added Christmas spirit -- we’ve got scattered rains in the extended outlook for Monday and our next cold front scheduled to arrive on Christmas Day.  As of now, we’re posting highs in the 70°s for both days, with another significant chill-down as we head into the mid-week.
So ... 70°s today, freezes for Friday and Saturday, then back to 70°s for Christmas -- enjoy the ride on our Louisiana Winter-Weather Roller-Coaster!

Tuesday, December 11, 2012

Sunshine Returns Wednesday!

By Jay Grymes & Steve Caparotta

We expected the high clouds to hang around through the day today, with our forecast on Monday evening calling for a “sun/cloud mix, possible more clouds than sun” for Tuesday afternoon. But the fact is, the clouds were a bit thicker and more persistent at times than I had anticipated. What was interesting in watching the sky through much of the afternoon was the obvious “cloud line” that lingered in the western sky -- you knew that they were getting plenty sunshine on the western side of the Atchafalaya Basin, but the clearing line just didn’t seem to want to ease its way eastward.

Our afternoon clouds filtered the sunshine sufficiently to keep highs in the 40°s for many WAFB communities, especially for those along and north of the I-10/12 corridor. Quite that change after a run of days with highs in the 70°s, eh?

In fact, some neighborhoods to the east of metro Baton Rouge may have even seen a little extra-light drizzle or mist today thanks to the high clouds. Those clouds stay with us for most of the night, but metro BR will still see Wednesday morning lows slip down into the mid to upper 30°s.

Mostly to partly cloudy skies early Wednesday will give way to plenty of sunshine by the afternoon, and that should allow temps to rebound into the mid to upper 50°s for the afternoon. But those same clear skies, accompanied by a very dry air mass with dew points in the 20°s, will produce a light freeze for Thursday morning -- if we do dip to freezing, that will be the second freeze of the season for Metro Airport.

Afternoon temps on Thursday will reach the low 60°s under sunny skies, and a warming trend sets-in through the weekend. At the same time, our “weather attention” turns farther to the west as the next frontal system makes its way towards us. 

A Pacific front (generally not at cold as the Canadian front that moved through on Monday) will track across the central and southern Rockies on Friday, and move into the Central Plains by Saturday, with a cold front draped into Texas.

Timing of the system’s arrival in Louisiana remains a little unclear, but for now we’re going with scattered showers and t-storms during the latter half of the day on Saturday and extending into Sunday. At least one model is currently hinting at the cold front getting into the Bayou State then slowing and essentially stalling along or near the coast on Sunday. There is also a suggestion of a second system developing over the Southern Plains that could bring another round of rains late Monday or early Tuesday.

And a final was on this date 4 years ago that south Louisiana received one of our biggest snowfalls in recent history. Up to 8 inches of snow fell in Amite...certainly a rarity around here!

Thursday, December 6, 2012

Sunshine Returning Friday Afternoon

By Steve Caparotta

A weak area of low pressure lingering along our coast kept many of us under the clouds yet again today. While we did see a few peaks of blue skies around metro Baton Rouge, we also saw a few passing showers this afternoon. Look for skies to remain mostly cloudy overnight, with a slim chance of a shower. Returning areas of fog will be our biggest concern.

Friday starts out with plenty of low clouds and fog, but I expect to see more in the way of sunshine by the afternoon. That should allow highs to climb into the mid 70°s. A stray shower can’t be completely ruled out, but most of us should stay dry. That forecast should hold pretty well for Saturday as well...and that's good news for the Cortana Kiwanis Christmas Parade in downtown Baton Rouge Saturday evening.

Sunday will be yet another day starting out with fog, followed by mostly cloudy skies and isolated showers in the afternoon. It’s late Sunday night into Monday when things look to get a bit more interesting in our weather…

A strong cold front will approach the area from the west, delivering numerous showers and t-storms on Monday. It’s still a bit too soon to say with much certainty, but the possibility of a strong storm or two may exist. The biggest story though will be the cool-down in the wake of Monday’s front. In fact, high temperatures for the day will likely occur in the morning, with readings falling during the afternoon.

Highs are expected to be stuck in the 50°s on Tuesday and Wednesday, with lows dipping into the 30°s! That cold weather that so many of you have been asking for should finally return next week!

While many cold fronts sweep the area clear of clouds with their passage, it appears as though the southern branch of the jet stream will remain overhead through much or all of next week. What does that mean? Look for clouds and even the chance of a few showers to stay with us through the balance of the week.

Wednesday, December 5, 2012

Rains to End, Back into the 70°s

By Jay Grymes & Steve Caparotta

Although the steadier, heavier rains ended during the morning hours for much of the WAFB viewing area, pockets of drizzle and mist continued through the day, making for a damp and cool afternoon. With the light rains and lowering clouds, daytime temps stayed well-below the forecasted numbers -- most WAFB neighborhoods reported afternoon highs in the low to mid 60°s.

Yes, Wednesday was a disagreeable day ... but most of us really needed the rain. A quick scan of regional rainfall totals showed much of the WAFB area received more than 1” of rain, with some areas topping 3” for the event. Peak totals topped 4” based on Doppler-radar estimates, including a nearly-continuous swath extending from NW Iberville Parish across lower Pointe Coupee and into southern West Feliciana Parish.

Most of the sprinkles for metro Baton Rouge will end tonight, but the cool front that brought the rains yesterday is expected to linger along the coast through much of Thursday. That means a few showers could extend into at least the first part of Thursday along the coast, but we think any “measurable” rain will tend to remain south of New Orleans.

So the rains will end but we’ll trade the sprinkles for fog during the overnight hours: areas of fog -- some possibly rather dense -- greets morning commuters on Thursday. Although we do expect to see some sunshine during the day, we anticipate mostly-cloudy skies for the better part of Thursday. But even with the clouds, a quick return of southeast winds by the afternoon should help highs climb back into the 70°s for Thursday afternoon.

The warm-up will continue through Friday and into the weekend. Morning lows for Thursday through Sunday will be in the upper 50°s, with highs in the upper 70°s for Friday, Saturday and Sunday.

With southeast-to-south winds expected through the next four days, low-level moisture will be more than adequate for morning fog each day. And given the daytime warmth (by December standards) over the coming days, we can’t rule out a ‘blip’ or two about every day through Sunday. But we’re keeping our forecast mainly-dry, only acknowledging spotty rains for Saturday and better rain chances for Sunday.

By Sunday, our next front will be approaching from the northwest. The timing is still a little uncertain at this time, but a best-guess brings the front into the WAFB viewing area very late Sunday into the early hours Monday. And after a very mild first week or so of December, this front should deliver a significant cool-down by early next week.

Tuesday, December 4, 2012

  -- Jay Grymes & Steve Caparotta
         4 December 2012
The rains arrived earlier in the day than we had expected, and it looks like they’ll be with us through the evening and overnight tonight. In addition, the early arrival of today’s rains meant that afternoon temps stayed well-below our forecast range, with Metro Airport failing to reach 70° for the day.
As of 4PM, the cool front we’ve been following over the past couple of days is draped from central Arkansas through the ArkLaTex region and southwestward into east Texas -- and it is still on schedule to move into our viewing area early tomorrow. The problem is that once it arrives, it looks like it will slow to a near-crawl from the pre-dawn hours on Wednesday into the late afternoon.
There have been a few imbedded t-storms in the pre-frontal rain bands today, but there does not appear to be a real “severe weather” threat for the viewing area during the evening, overnight or even tomorrow morning. Although the front will slow as it passes through the area, the t-storm action will remain limited.
However, given the slow movement of the system, we could see some fairly significant rain totals for a few neighborhoods. Some preliminary radar estimates are already showing some 1” and even a couple of 2” bull’s eyes in the WAFB viewing area this afternoon, although the vast majority of WAFB neighborhoods are reporting a ½” or less thus far. But given that we could see rains continuing into the lunch hour on Wednesday for some communities, we can expect a flurry of 1” totals around the region from our area Weather Watchers by tomorrow afternoon.
Skies should start showing some clearing by late Wednesday, with dry days expected for Thursday and Friday. But be advised, even with the cool front working through, the air stays mild to warm, with patchy fog likely for Wednesday, Thursday and Friday mornings.
In fact, what we won’t see with our Wednesday front is a significant cool-down. Many WAFB watchers should expect daytime highs to remain in the 70°s for the entire work week, with upper 70°s on the forecast board for the weekend! We’ll put spotty to isolated rains in the weekend forecast as well, but the main weather story after Wednesday will be the unusually-warm weather persisting into next week.
In the extended outlook, the guidance is a bit mixed. For now, we’ll call for another front to arrive during the early part of next week, delivering another chance of rain.