Tuesday, March 31, 2015

Warm, Small Rain Chances on Wednesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- areas of fog possible for Wednesday morning
- staying with highs in the 80°s through Friday
- slight uptick in rain chances for Thursday, late Friday and early Saturday

It was another warm day to close out the month of March, with many neighborhoods reaching the 80°s once again under a mix of sun and clouds.  For Baton Rouge’s Metro Airport (BTR), today marks the third straight day with highs in the 80°s, with three more days in the 80°s expected as we close out the work week.

Our forecast for Wednesday -- April Fool’s Day -- calls for a morning start on the mild-and-somewhat-muggy side, with low clouds and areas of fog to begin the day.  Look for a low around 60° to the low 60°s for the first day of April here in the Capital City area.  We expect something similar to the last couple of afternoons for Wednesday, with a high in the low 80°s under partly cloudy skies to a sun/cloud mix.  We may also see a few blips on Doppler radar for Wednesday afternoon, but the vast majority of WAFB neighborhoods will stay dry through the day.

As we get into Thursday, a weak upper-level disturbance currently over Mexico rolls across the central Gulf Coast region.  Usually these can be decent rainmakers, but the last couple of these to come through our area have failed to deliver on the expected rains.  This set-up looks much the same: the models are hinting that this disturbance will get “stretched” and lose some of its form before it arrives.  As such, we’ll go with modest rain chances for Thursday at about 30% or so.

Most of Friday stays dry, although we do have our next cold front approaching from the northwest.  But it looks as though the front doesn’t arrive until the late night hours (Friday into Saturday).  We’ll go with a 20% to 30% rain chance for Friday evening with those percentages rising to about 40% or so during the overnight and early morning hours Saturday.  Saturday afternoon should see some clearing and it turns noticeably cooler, with highs only reaching around 70° to the low 70°s for the Red Stick.

The forecast is a little blurry for the Sunday through Tuesday time frame as models are showing some passing disturbances in the region but differ on their strength and timing.  For now at least, we still believe that Easter Sunday morning remains dry, with only a 30% chance of rain through the rest of the day.  Look for scattered rains on Monday and Tuesday too.

Monday, March 30, 2015

Staying Warm, Limited Rain Chances

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- above-normal temps through Friday
- modest rain chances through the 7-day outlook

We’ve definitely hit a warm spell, with highs in the 80°s that started on Sunday and are expected to persist through Friday. By comparison, normal (i.e., the 30-year average based on 1981-2010) highs at this time of year are in the mid to upper 70°s for the Red Stick. Lows each day look to stay in the 60°s, compared to normal lows in the low to mid 50°s.

The warmer air is accompanied by more moisture (higher humidity), setting the stage for low-end rain chances -- at 20% or less -- for the next couple of days. As we get to Thursday, a weak upper-air disturbance from the west may offer a slight nudge to our local rain chances. Then comes our next front, scheduled for arrival late Friday or very early Saturday. That front should deliver scattered showers and t-storms, but for now at least, the front doesn’t look especially potent, so we see little threat from severe weather associated with its arrival.

It’s still way down the forecast road, but the current outlook for the weekend is not the greatest. While Friday’s front should clear the coast by Saturday late morning, it may stall over the coastal waters rather than sweep south quickly and “cleanly.” Add in another upper-level disturbance from the west and we have modest rain chances for Easter Sunday. We’ve got rain chances for Sunday at 30%, but more importantly for some, any rain that does fall looks to be the afternoon variety: all looks good for Sunrise Services.

On a different track for weather and climate news, the Mississippi River at Baton Rouge is now above flood stage, having risen above stage of 35.0 feet this past Thursday. The current forecast calls for the Baton Rouge gage to crest in the next couple of days just over 36 feet. 

We’ve had some inquiries in recent weeks about this, a lot of it motivated by the memories of the mega-flood back in 2011.

First and foremost, the river will not get anywhere near as high as it did in 2011 (45.0 feet) … for the time being it doesn’t look like the river will even get to 40.0 feet, at least not this spring. In addition, flood stage on the Mississippi River for Baton Rouge fails to include the height of the levee (45 feet or more) for the stretch of river running beside the Capital City. To put it all in perspective, the Mississippi River at Baton Rouge has risen above flood stage 11 times since 2001, including 3 times above 40.0 feet (2008, 2009 & 2011).

The bottom line: we’re just fine.

However, the river is high enough now to start the usual seepage and “sand boils” that we usually see this time of year in the Baton Rouge metro area, mainly along the ‘natural’ river floodplain that extends from the western foot of Baton Rouge’s South Boulevard downriver beyond the L'Auberge Casino. (Boils occur on the west side too.)

That 2011 reading is the 4th highest on record, and the second highest (behind 45.2 feet during April 1945) since the start of construction of a single "consolidated" levee system as mandated by the 1928 Flood Control Act. The 2011 Flood prompted the opening of the Morganza Spillway .. only the second time ever that the Corps of Engineers has opened it, and the only time the Corps opened it due to excessively high water along the river. (The other time was 1973 to reduce pressure on the River Control Structure upriver.)

Wednesday, March 25, 2015

Rain Likely on Thursday

By Jay Grymes & Steve Caparotta

March 25th WAFB First Alert Quickcast:

- gets wet for Thursday afternoon
- shaping up for a good looking weekend

We opened the day with areas of fog across the viewing area including a Dense Fog Advisory for parishes to our east and southeast.  Fortunately, most of the fog had cleared by mid-morning, leaving us with a fairly nice spring day.  A high deck of cirrus clouds through the afternoon kept us from enjoying an ‘A+’ beauty, but not enough clouds to really complain.

Look for a mild overnight as cloud cover increases, and many of us could be dealing with fog again in the morning.  But tomorrow’s weather story will be about the timing and amounts of rain.

Strong storms are prompting a Severe Weather Watch to our north today and this same system will be moving through Louisiana tomorrow afternoon.  But the way things look right now, we don’t anticipate a severe weather outbreak as the front rolls through.  There will be thunderstorms in the area on Thursday, and one or two could be on the strong side, but our current guidance is suggesting that we’ll not have the elevated instability and upper-level support that they have seen the past two days in the U.S. Plains.

Most of our models are currently showing modest rain totals with tomorrow’s front -- generally in the 0.25” to 0.50” range -- with one or two running a tad higher.  If you happen to get under one of the stronger storms tomorrow, your local total could get top one inch, but for most of us this won’t be a big problem.

As for the timing tomorrow, we’re thinking that the main activity will run from around noon through the afternoon, then winding down into the early evening.  So the morning drive will be dry, but plan on scattered rains during the evening Rush Hour commute.

We’ll start the day around 60° in the Capital City, with Thursday’s highs climbing into the low to mid 70°s for most WAFB neighborhoods.

Clouds will likely linger into Thursday night but skies will be clearing into Friday morning as a drier continental air mass takes hold.  It looks like a cool start for Friday with sun-up temperatures in the mid 40°s for the Red Stick … and it stays comfortably cool through the day too, with highs in the upper 60°s for many of us under sunny skies.

That sets us up for a great weekend: lots of sunshine on Saturday and Sunday with highs for both days in the 70°s -- make your plans now to take advantage of a superb spring weekend.

Our extended outlook sees showers slowly sneaking back into the forecast early next week.

Monday, March 23, 2015

More Sun, Warmer for Tuesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- another mild day for Tuesday
- rain returns to the forecast by mid-week

Our day stayed a little cooler than we expected as a mostly cloudy sky coupled with NW-to-northerly breezes helped slow the daytime warm-up. Maybe not as pretty of a day as anticipated, but all in all, there is little to complain about. We’ll stay dry through the evening and overnight under partly cloudy skies, with patchy fog expected for the Tuesday morning start. We’re expecting a cooler start in the morning as well, with lows for the Capital City in the low 50°s -- cool but not chilly for the morning.

Our forecast stays mainly-dry through Wednesday. It’s a sun/cloud mix for Tuesday with partly cloudy skies on Wednesday. We’ll note that a spotty shower or two can’t be ruled out for Wednesday afternoon, but with rain chances at under 20%, it hardly deserves mention.

Our next front on the forecast board delivers scattered showers and a few t-storms on Thursday, with isolated showers lingering into early Friday. For the time being, there is no serious threat for severe weather in the Thursday/Friday time frame and even the rain chances for Thursday and Friday are still a bit up in the air. The main energy producing the rain potential on Thursday and Friday is tied to an upper-air trough that crosses the nation, with the core of the trough remaining to our north. Current rain projections from the NWS Weather Prediction Center keep totals under 0.5” for the entire WAFB area -- another sign that the frontal action should be fairly benign.

By Friday afternoon, the trough has shifted well to the east and northeast, leaving us with a fine afternoon and a good-looking weekend ahead, with plenty of sunshine. 

However, the extended-range guidance is a bit “scattered” when it comes to the weekend temperatures! There is no doubt that it will be noticeably cooler for Friday, Saturday and Sunday, but just how cool is still a little unclear. We’ll give it a couple of days, with the expectation that the models will start to close the gap in terms of their temperature differences. (Regardless of how the temperatures shape up at week’s end, we believe that we are done with freezes for the season.)

In the meantime, one of the topics of national chatter in weather circles has been the lack of severe weather in general, and the record-low number of Watches posted through the third week of March. Since January 1st, the NWS Storm Prediction Center has issued just 4 Tornado Watches and no Severe Thunderstorm Watches. In a normal year, one would expect 40 to 50 Watches by this time of year (based on records back to 1970). March is traditionally the kick-off month for severe weather in the U.S., yet there have been no Watches issued anywhere this month, the first time ever to go this deep into the month without a single Watch being issued.

Tornado counts are also way below average thus far. Preliminary counts (through yesterday) put the national number at just 28. Based on the past 10 years (2005 - 2014), that’s less than half the number compared to the previous low count of 57 (through March 22) in 2010, and just 12% of the 10-year average through the date.

Why mention this? Two reasons: (1) we don’t want you to get complacent about severe weather even though it has been unusually quiet: historically, nearly half of our area’s severe weather occurs at this time of year (March thru May), and (2) the Storm Prediction Center experts note that there is no correlation between a “quiet” start to the spring and the level of activity through the remainder of the calendar year. Keep your guard up for severe weather!

Wednesday, March 18, 2015

Keep the Umbrellas Handy

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- just some passing showers this afternoon and evening
- only modest rain chances (30%) for Thursday & Friday
- rains return for a wet weekend ahead

Today’s rains were a considerably less impressive than we had anticipated yesterday.  The evening commute was much drier than expected - - no complaints there - - and what rains that did develop will be out of the area this evening.

Today’s limited rains were the result of an upper-level low that “opened up” (became less defined) as it tracked across Texas, Oklahoma and Arkansas.  Unlike what most of our guidance was suggesting even as late as this morning, it simply did not generate much in the way of activity in our area, and Doppler radar and lightning detection made it clear that there were very few thunderstorms.  It’s moving to the northeast rather quickly now, and most of the rain in the WAFB viewing area will be done by or even before 8:00pm.

Expect a dry wake-up for Thursday under mostly cloudy skies with patches of light fog at sunrise.  We won't go entirely rain-free, but Thursday and Friday look drier than today: we'll call for a 30% rain chance, mainly the afternoon variety, for both days. Look for temperatures on both days to remain above normal: morning lows in the low 60°s, afternoons up around 80° or so for most of us.

Over the past two days we’ve also mentioned an upper-low just off the Southern California Coast.  This system will become better organized -- likely becoming a “cut off” low -- over the next day or so as it moves east along the U.S./Mexico border.  This Desert Low has the potential to be a much more active rainmaker for us … and is shaping up to deliver a disappointingly wet weekend ahead.  Timing of the weekend rains is still an issue, with the American GFS model suggesting rains could start arriving as early as late Friday or early Saturday.  The European model holds the rains off until the latter half of Saturday, and is the ‘drier’ of the two models as well.

We’ve still got a couple of days to fine-tune the weekend outlook, but for now we’re going with “rain likely” for both Saturday and Sunday.  If the GFS is closer to correct, Saturday could be a wet mess just about all day long, with periods of rain on Sunday.  The ‘Euro’ makes Sunday look like the wetter of the two days, but neither day being a n all-day wash-out.  More importantly, at this time neither of these two extended-range models is suggesting significant severe weather for the weekend nor exceptionally heavy rain.

As of early this morning, The NWS hydrometeorologists at the Weather Prediction Center (WPC) are calling for regional totals on the order of 1” to 2” for most of the WAFB viewing area between today and Monday morning.  The WPC’s rain forecast shows an increasing gradient from the coast to the northern portions of the viewing area, with totals of 2” to 3” possible for some of our SW Mississippi counties.​

Tuesday, March 17, 2015

Rains Arriving on Wednesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- a wet Wednesday in store for most
- scattered rains for Thursday & Friday
- looks fairly wet for the weekend too

Today was the third straight day in the 80°s for most WAFB neighborhoods.  The 86° high for metro Airport is the highest reading since October 28th.  Today was also the muggiest of the three days too.  The increase in low-level humidity is a hint of what is on its way.

We all stay dry this evening and overnight, although the moist air should help generate some patchy fog before sunrise on Wednesday.  Look for a morning start in the low to mid 60°s for the Capital City but it should be a dry morning drive: it will be a different story for the commute home.

The first showers should start to pop-up by or before mid-morning, with scattered rains in the area by lunchtime.  We’re going with a 60% to 70% rain chance for the afternoon -- showers and t-storms likely -- with a very slight chance (“Marginal” in the weather speak of the NWS Storm Prediction Center) of a strong to severe thunderstorm or two during the afternoon hours.  Rains should slowly wind down into the evening.  With the rain and clouds, we’re looking at a daytime high topping out in the upper 70°s instead of our recent run of 80°s.

Our forecast for Thursday and Friday comes with somewhat low confidence: some of our guidance wants to make a pair of relatively wet days to follow Wednesday’s lead but we’re thinking a drier pair of days, with rain chances closer to 30% to 40%.

Unfortunately, the weekend is shaping up to be a wet one based on the way things look right now: we’re going with rain chances at around 60% to 70% for both days with the rain lingering into early Monday before ending.  Temperatures will be a little cooler for the weekend too, with daytime highs running in the 70° to 72° range for Baton Rouge.

Why the wet forecasts for Wednesday and the weekend?

Wednesday’s rains will be courtesy of the upper-level low we’ve been watching the past couple of days that is currently tracking across northern Mexico.  That system has already delivered rains to sections of Texas.  We expect this low to pick up a little forward speed overnight and be a rainmaker for us tomorrow as it tracks to the east-northeast across the lower Mississippi Valley.

Although we’ll have a series of disturbances to our north tracking from west-to-east on Thursday and Friday, our gut feeling is that these won’t be significant rainmakers but they will have just enough energy to keep things unsettled as they pass by.

The weekend activity will be the result of a deepening low that is currently off the California Coast.  It doesn’t look overly impressive right now, but guidance suggests it will get better organized once the upper low currently over northern Mexico makes its run to the east.

Preliminary indications from NWS hydrometeorologists at the Weather Prediction Center are calling for widespread rain totals of 1” to 2” between now and Sunday evening for much of the WAFB viewing area with localized totals of 3” possible for the northern half of the viewing area.  That’s enough to get our attention: we’ll keep a close watch on those projections in the coming days.

Monday, March 16, 2015

Warm, Mainly Dry Again on Tuesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- another mild day for Tuesday
- rain returns to the forecast by mid-week

It would be hard to complain about the weather over the past weekend … and today was a nice one too.  Today’s high cirrus clouds did little to filter the sunshine, allowing temperatures around the Capital City to return to the 80°s for the second consecutive day.  Our forecast for Tuesday calls for a third straight day in the 80°s -- the first time that’s happened since late October.  Yes, spring is finally on its way. 

The mild-to-warm weekend prompted at least a half-dozen people to ask, “Is Baton Rouge done with freezes?”

Let’s start with the historical statistics.  Based on data back to 1893, there is still a slight chance that we could have another freeze: roughly a 12% chance, or odds running about 1-in-8.  The last time we had a freeze after March 15th was just two years ago, when a rogue winter blast delivered a low of 29° on March 27th.  In fact, over the course of the 120+ year-long record, there have even been two late-season freezes in April: in 1940 (31° on April 13th, the latest ever for Baton Rouge) and in 1987 (32° on April 4th).

But in the greater scheme of things, another freeze this year seems rather unlikely -- even below those 1-in-8 odds.  And if another freeze were to sneak into the region, it would likely be very brief and fairly inconsequential.  Yes, again, spring is finally on its way.  At this time of year, our weather concerns shift for cold spells to severe weather and flooding.  And we’ve been lucky (so far) on both counts.

Tuesday will open with another mild morning under a partly-to-mostly cloudy sky with Red Stick temps in the 60°s at sunrise.  We could see some patchy fog for the morning drive, but we don’t anticipate anything so “soupy” as to be a problem for the commute.  For the afternoon, plan for a sun/cloud mix, a slight uptick in humidity -- although not uncomfortably humid -- and highs in the low 80°s. 

After that, however, we return to an unsettled weather pattern where we’ll be dodging rains right into the weekend.  An upper-level low that has been locked in place to our west will finally begin moving eastward, increasing rain chances as it approaches and passes-by this week.  At this point, we don’t anticipate anything severe through the coming week, nor are we concerned at this point about heavy, flood-potential rains.  Our preliminary guidance is suggesting rains of up to 2.0” to 2.5” between now and Sunday – very wet but not enough to generate serious problems.

A slight chance of showers even creeps into the local forecast late Tuesday. Then it’s scattered rains and highs in the 70°s for Wednesday through Friday with morning starts for Baton Rouge in the 60°s for all three days.  As of now, it looks like things get wetter for Saturday into early Sunday before we start to see some clearing.  Saturday and Sunday will be cooler too, but still far from cold.

Yes, spring is finally on its way.  In fact, we think that it has arrived!  (Craneflies, mosquitoes and yellow-green pollen on your windshield … all the signs are there!)

Friday, March 13, 2015

Finally Drying Out This Weekend!

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- finally, an end to the rains
- mostly cloudy but mainly dry and mild weekend ahead

For many WAFB neighborhoods, last night’s and this morning’s rains were the heaviest of this rather soggy week.  We also had a few thunderstorms in the viewing area through the night, apparently enough to knock the power out for a few thousand WAFB area residents.  In fact, late last night the NWS briefly posted a TORNADO WARNING for parts of Lafourche and Terrebonne parishes, prompted by a thunderstorm that had the tell-tale radar signature of a possible waterspout moving inland off the Gulf (no confirmation as of this afternoon).

Thankfully, the end to the “good-for-ducks weather” has finally arrived.  Yes, we might see a light sprinkle or two this evening for areas mainly to the east of metro BR, but all in all we can all put the umbrellas away for a while.

The FLASH FLOOD WATCHES have expired too.  Standing water is still a problem in the usual places, but it has not been as serious as we were anticipating just a few days ago.  And local rivers and bayous will need to be monitored through the weekend as they will all display marked rises, but we’re expecting most of the reporting sites in our viewing area to crest below flood.

Although the Comite River will see a big rise this evening and into tomorrow, it looks like that EBR river tops out well-below flood stage.  We’ll want to keep a closer watch on the middle and lower Amite, depending on how much rain fell last night and this morning above Denham Springs -- but again, all forecast points along the river should remain below flood although several could get very close.

The Tickfaw and Natalbany will see steady rises today and tomorrow as well, but the latest guidance keeps both below flood stage along their courses.  Only the lower Tangipahoa is currently forecasted to go into flood, with the NWS Lower Mississippi River Forecast Center calling for Robert to crest 1.5 feet above flood stage late Saturday into Sunday.

So what about the weekend outlook?  The most appreciated word for Saturday and Sunday will be “dry.”

A drier (less humid) air mass from the west and northwest will take charge over the next few days and that should deliver morning lows in the 50°s instead of the muggy 60°s that many of us have experienced over this recent wet spell.  Weekend afternoons will climb into the mid to upper 70°s for both days for most WAFB communities.  Although mainly dry, Saturday and Sunday won’t be the prettiest of spring days: we expect morning fog and a mix of sun-and-clouds for both days.  Some of our guidance is even hinting at a few showers for Sunday afternoon -- we’ll post it as “spotty” for the time being, but our hunch is that we won’t see anything, or at least nothing significant.

So the weekend delivers a big improvement -- and for parade lovers, Saturday’s “Wearin’ of the Green” should go off without a hitch!

We’ve got a sun/cloud mix Monday on the forecast books for Monday: after that the forecast gets a bit muddled.  The extended guidance hints at a slight chance of rain as early as Tuesday, with scattered rains back in the local area by mid-week.  Temperatures look like they stay will remain spring-like and mild into the middle of next week too.​

Thursday, March 12, 2015

Rains Finally Diminish on Friday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- FLASH FLOOD WATCH continues into Friday
- drier air begins filtering in by Friday afternoon

We’re still not down with the rains! But as we’ve seen the past couple of days, the threat of heavier rains has failed to materialize for most WAFB communities ... at least so far.

We’ve still got “rain likely” in the forecast for tonight and early Friday. Be ready for rain into the Friday morning commute -- and we may even get a few t-storms, although the chance of any severe weather is pretty low. Add in some patchy fog for good measure, and it looks like a messy Friday morning drive. Morning temperatures will be in the low to mid 60°s for the Red Stick.

A FLASH FLOOD WATCH remains in effect until Friday afternoon ... and there is still a potential for as much as 1” to 3” of rain tonight and into the first half of Friday based on our computer guidance models. But we must admit, the models have been running too wet the past few days and we suspect that the trend may continue for tonight and early tomorrow. 

Still we’ve had enough rain to get the area rivers on the rise … and that will need watching in the coming days. A preliminary forecast for the Tangipahoa River at Robert calls for the site to go into flood on Saturday and crest at 1.5 ft above flood stage between Saturday and Sunday. Elsewhere, no other forecast points are currently expected to reach flood, but we’ll keep tabs on the Amite, the Tickfaw and the Natalbany.

And yes, there is light at the end of this “rain” tunnel! 

The rain should be subsiding from west-to-east during the day on Friday, with drier air filtering into the viewing area from the west through the afternoon. We’ll stay under mostly cloudy skies, but the dry-out should be accompanied by mild afternoon temperatures in the low to mid 70°s for most WAFB neighborhoods.

As the drier air (lower dew points) continues to take hold, we can expect cooler morning starts for the weekend: we’re going with lows in the mid 50°s for both Saturday and Sunday. While we can’t say absolutely no chance of rain this weekend, we’ll call it “spotty at best” for both days under a sun/cloud mix with highs in the mid 70°s.

The outlook for next week calls for some more nice spring days: lows in the 50°s and highs in the 70°s. Confidence late in the week is on the low side right now, but we’ll suggest isolated showers for Wednesday with scattered showers and t-storms for Thursday.

Wednesday, March 11, 2015

Flash Flood Watch Continues...

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- FLASH FLOOD WATCH extended through Friday 6:00pm for areas east of the Atchafalaya
- FLASH FLOOD WATCH canceled for areas west of the Atchafalaya
- still a potential for an additional 1” to 3” of rain between now and Friday evening

It was unquestionably quieter today in terms of area rains today compared to yesterday. In fact, a few neighborhoods even got some glimpses of faded blue skies and streaks of sunshine. But all of our model guidance -- as well as our latest radar trends -- indicate that our run of rainy days is far from over.

Both of our high-resolution, short-term models -- the HRRR and our in-house RPM -- are showing a broad swath of rain moving into Louisiana form the Gulf this evening and staying with us through most of the night. After that, we could see another quiet spell with limited rains through the first half of Thursday before the next wave makes it into the viewing area later in the day.

Regional rains will continue to arrive in periodic waves through a good bit of Friday, with rains tapering off during the latter half of the day. Although we could spend a good bit of Saturday under mostly cloudy skies, we expect the weather to be just fine for “The Wearing of the Green” in Baton Rouge.

From a temperature standpoint, our recent run of mild days will continue. We’ve got afternoon highs posted in the 70°s right through the weekend and into next week. As for lows, we expect the Gulf air mass currently in place will keep our morning starts in the 60°s for Thursday and Friday. Be ready for patchy fog on both mornings too.

As we head into the weekend, the upper-air pattern and series of disturbances that have kept skies gray and yards wet will shift to the east. With that shift, a slightly drier and less humid (lower dewpoints) air mass from the west and northwest will be moving into the lower Mississippi Valley. That should mean morning minimums in the 50°s for the weekend and continuing into next week.

So what about the rains? Admittedly, totals for most WAFB communities through this afternoon are lower than what we had anticipated earlier in the week. While several waves of rains have arrived over the past few days, thankfully they have not been as “productive” as we expected. Still, there are lots of WAFB neighborhoods that have received more than 1” of rain thus far, and we still have two potentially “wet” days ahead -- Thursday and Friday. 

As of this morning, the NWS Weather Prediction Center was still showing a 4” bullseye for the upcoming three-day total (from this morning through early Saturday) centered right over South Louisiana. We’re thinking that number may be on the high side for our area, although we won’t rule out the possibility of one or two spots topping 4” in the coming days. However, something more like widespread 1” to 2” -- with some scattered totals of 3" or more -- seems a bit more likely given the forecasted rain patterns through Friday.

These lower multi-day forecasted rain totals are obviously good news. We’ll still be watching for street flooding and excess water problems in the usual places, but we are a little less concerned about flooding along area rivers and bayous. That said, we still need to watch our local waterways closely over the next few days as we await the arrival of additional periods of rain. 

Tuesday, March 10, 2015

Flash Flood Watch into Thursday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- staying mild, more rain on the way
- FLASH FLOOD WATCH in effect through Thursday

It certainly hasn’t been dry … but many of us in the WAFB area have had the good fortune to miss out on the bigger rains over the past 24 to 48 hours. Radar estimates and Weather Watcher reports show some broad swaths of 1” to 2” rain totals to the east and west of the WAFB viewing area over the past two days, with a few metro Baton Rouge neighborhoods getting a pretty good dousing overnight and earlier today. However, the majority of WAFB neighborhoods have dodged heavy rains thus far.

For the most part, most of our viewing area was relatively quiet through mid-day today. However, that will change this evening and overnight ... and it looks like we’ll stay rather wet over the next couple of days. As a result, the National Weather Service has issued a FLASH FLOOD WATCH for the entire WAFB viewing area through Thursday evening. 

Just like today, we’re not anticipating “all day rains” between now and Friday, but we do expect additional waves of rains (disturbances from the southwest) as they continue to run inland along the upper-air flow.

Our primary rain forecast models are still suggesting additional rains of 1” to more than 4” between now and Friday; at the same time, the NWS Weather Prediction Center is posting a forecast for widespread rains of up to 3” or more over most or all WAFB communities between now and the start of the weekend. With most of south Louisiana’s key rivers already at or above median flows for this time of year, the additional rains in the coming days will need to be monitored closely for river flood potential. Elsewhere, be prepared for standing water in the usual spots as you go out and about through the rest of the work week.

The damp, mild Gulf air will also be conducive for the periodic development of locally-dense fog over the next few days. And we can’t rule out an occasional thunderstorm, although we do not anticipate any severe storms during this rainy period. Temperatures will remain on the mild side through the week as the Gulf air mass dominates: look for morning lows in the 60°s with afternoon highs in the 70°s through Friday for the metro area. 

We’ve also extended the elevated rain chances into Friday before we get a final clear-out heading into the weekend. By Saturday morning, a “drier” continental air mass will start working its way into the lower Mississippi Valley from the west and northwest. The persistent upper-level flow pattern from the southwest that is delivering the rain-making disturbances will finally shift east, allowing for a drier weather regime to take hold.

We could still have a sprinkle or two for early Saturday with a morning start in the 50°s, but the weather should improve through the day -- go ahead and make your family plans to enjoy the “Wearing of the Green” St. Paddy’s Parade in Baton Rouge. We’re expecting slow clearing through the day on Saturday with highs in the 70°s. And based on the current outlook, Sunday should be a nice spring day across the entire area.

The outlook for early next week is promising too: a mainly-dry pattern persists with more mild March temperatures through the first half of the week.

Monday, March 9, 2015

Staying Wet Most of This Week

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- mild temperatures but staying wet this week
- rain totals in excess of 3” to 4” possible between now and mid-day Friday

Let’s start with the good news: after a string of freezes during the first week of March -- including a rather uncommon March dip into the 20°s -- we’re on track for near-normal temperatures this week as a mild Gulf air mass dominates our weather. 

The trade-off for our milder temperatures this week will be a run of rainy days, and that is where the not-so-good news comes in.  Based on the extended guidance and a sense of the projected upper-air pattern, many WAFB neighborhoods could see 2” to 4” of rain this week with some locally-higher totals.  Standing water and nuisance street flooding could be an issue for many of us and we’ll need to keep watch on our area rivers too should some of the bigger rain totals become more widespread.

It’s a bit coincidental, but the NWS Climate Prediction Center (CPC) has also declared that a “weak” El Niño has finally become established.  While our expected run of rain this week cannot be directly attributed to the CPC’s El Niño declaration, history tells us that El Niños tend to make for wetter-than-normal winters and springs for our viewing area.  In fact, El Niños are linked to wet winters and springs around the entire Gulf rim.  For southeast Louisiana, rainfall for roughly 7-in-10 winter/spring periods averages above-normal when an El Niño is present.

(As a quick reminder, El Niño is represented by warmer-than-normal waters over the central and eastern equatorial Pacific Ocean.  These warmer waters interact with the atmosphere and affect the atmosphere’s circulation pattern.  For the Gulf of Mexico region, the presence of an El Niño is associated with an increase in the development of non-tropical lows over the Gulf of Mexico.  More lows in the Gulf translates into more raindays for the region.)

A key factor in our “wet” forecast for this week is the anticipated upper-air pattern to our west and southwest through the coming days.  Our forecast models show a persistent, deep trough extending down over Old Mexico through the middle to latter part of the week.  This pattern will provide a steady southwesterly flow over the Gulf Coast states.  Such a set-up tends to keep us under the influence of mild Gulf temperatures but it also pulls Gulf moisture inland while providing mid/upper-level lift to encourage rain and t-storm development.  The pattern also drives rain-making disturbances along the southwesterly flow and over the region, adding to the rain-making mechanisms.

We expect this pattern to persist through Thursday, at least.  Look for daily lows in the 60°s for the next three days with daily high temperatures in the upper 60°s to low 70°s.  the air will remain muggy throughout the next several days, and periods of low clouds and patchy fog will make for less-than-attractive days.

Heading into Friday, the upper-level pattern will begin to modify, delivering a drier weather pattern for the weekend along with cooler morning starts.

Thursday, March 5, 2015

Dry, Still Chilly on Friday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- sleet reports extend all the way south to the I-10/12 corridor today
- ‘Hard Freeze’ potential for northern portions of the WAFB viewing area overnight

Once again, Mother Nature pushed the frozen precipitation line farther south than Jay expected, although there were little if any ground-layer accumulations to be found.  However, a concern for icing on roadways prompted some evening cancellations in the region.

All in all, it was close to a “non-event” from a winter weather perspective, with those accumulations that were reported -- and photographed -- mainly occurring on windshields, metal objects (e.g., car hoods), elevated porches and vegetation.  But even those were a bit of a surprise!

So what happened?  The temperatures stayed a few degrees cooler through the day then our guidance suggested, and that was just enough to get the “wet sleet” and pockets of snowflakes down to places as far south as New Iberia (according to the automated weather station there).

Indeed, we still think the temperature story over the past 24 hours is the biggest weather story of the event, with a number of sites reporting 50° temperature changes over a 24-hour window.  Admittedly, we don’t have an easy way to assess this, but we’d bet ‘dollars-to-donuts’ that such a temperature drop is an exceedingly rare occurrence in our area.  Something that has happened only a very few times over the past 100 years?  (We’re not ready to say never before -- but it’s not out of the question.)

Skies will continue to clear from west-to-east through the evening, setting us up for a very cold night.  Some of our northern viewers will drop down to near freezing during the evening and we’ve got metro BR at freezing by midnight.  That’s cold enough -- with freeze durations long enough -- to prompt the NWS to issue Freeze Warnings for the viewing area.  In fact, we expect that some folks up along and north of the LA/MS state line might just meet ‘Hard Freeze’ criteria -- temperatures at or below 26° for several hours.  We’re anticipating a low of 26° for Metro Airport for Friday morning.

Abundant sunshine under mainly clear skies through the day on Friday should get metro Baton Rouge into the low 50°s by the afternoon -- certainly much warmer than today but still nearly 20° below normal for early March.  Then it’s back below freezing for many of us on Saturday morning, with a Saturday afternoon high in the low 60°s under fair skies.

After that, the forecast gets rather “cloudy” (unclear) through the work week.  A series of west-to-east traveling mid/upper-level disturbances will keep our weather “unsettled,” with decent rain chances each day.  Most of these will be scattered rains, so not everyone gets wet every day.  Monday looks to be the “wettest” day of the week, but for now we see no “rain-free” days through the entire upcoming week.

In addition to the scattered rains through next week, temperatures will remain below-normal too.

Monday, March 2, 2015

Breezy & Warm Next Couple of Days

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- very wet today in some parts of the viewing area
- fog lingers this evening and through the night
- from the 70°s to 40°s at mid week

Pockets of rather thick fog for some locations and rains of 3” or more in others to start off the work week: not exactly what the doctor ordered.  And many of us could still be dealing with some thick fog tomorrow morning. The NWS has already posted a Dense Fog Advisory for just about the entire WAFB viewing area, going into effect this evening and 9 p.m. and remaining in effect until 9 a.m. tomorrow. 

It will be a mild, muggy night and morning start for Tuesday.  Not only with the fog and the possibility of a passing shower or two, but also given a forecasted low near 60° for the Capital City.  In the meantime, radar and storm reports are indicating some substantial 24-hour rain totals, led by a whopping 5.26” in Liberty, MS as of 3PM.

All of this going on as we watch a warm front lift northward through our viewing area.  That has generated an impressive temperature gradient across the viewing area: 4PM temperatures were in the mid and upper 70°s in Ascension Parish, the mid 60°s in EBR Parish, but down into the 50°s for parts of the Felicianas and Pointe Coupee Parish.  That gradient should slacken as the warm front lifts north tonight.

We’ll keep a 30% to 40% rain chance in the forecast for Tuesday -- mainly for showers in the afternoon but a rumble or two of thunder can’t be ruled out.  In addition, Tuesday will be breezy and quite warm with highs in the upper 70°s for the Red Stick.

We’re going a little warmer for Wednesday, with a morning start in the low to mid 60°s for metro BR and an afternoon high maybe a degree or so higher than Tuesday.  And like Tuesday, fog could be an issue for the Wednesday morning drive. 

Our next front is scheduled to arrive late Wednesday into the early hours Thursday, and this front will leave a mark!  We’re not concerned about severe weather, but you will the impact of the Arctic air mass behind the front as temperatures will plummet.  The additional issue of concern with the mid-week cold front is the potential for wintry precipitation.  Our thinking is that there is little chance for snow or sleet accumulations in the viewing area.  However, areas north of the Capital City may see temperatures drop quickly enough to support the onset of pockets of freezing rain, especially over elevated roads and bridges.

However, timing of the lingering rains behind the front and the arrival and southward extend of sub-freezing temperatures is still in question right now.  We’ll need to watch as the forecast models adjust and fine-tune the weather picture for Wednesday night and early Thursday over the next 24 to 48 hours.  In the meantime, our gut feeling right now is that metro BR misses out on the freezing rain threat.

After a cold Thursday afternoon with highs in the 40°s for metro BR and a light freeze for the Red Stick on Friday morning, temperatures should start a slow warming trend that carries through the weekend and into the following week.  Unfortunately, the rain outlook for the weekend is a little “cloudy” at this stage, so we’ll go with a low confidence outlook for scattered showers on both Saturday and Sunday.