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!)