Tuesday, September 30, 2014

Waiting on a Cold Front...

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- Scattered rains for Wednesday
- Showers & storms on Thursday and early Friday
- a true “taste of fall” for the weekend
- all quiet in the tropics

It was dry for just about the entire viewing area today; Tuesday’s weather chat at the water cooler was largely focused on the afternoon’s warmth and humidity with a summer-ish feel for the last day of September.

For most of us, we close out September on the “warm and dry” side of normal. WAFB area September temperatures averaged about 1°F above normal with Baton Rouge’s Metro Airport hitting the 90°s on 16 dates -- including the first 12 days of the month plus today! As for rain, a majority of WAFB regional sites reported below-normal September rainfall: many recording sites posted less than 3” of rain for September with a handful of locations recording less than 2” for the month. However, not everyone had a “dry” September -- St. Francisville, Marksville and Convent all topped 5” for the month and Donaldsonville recorded more than 10” of rain over the 30 days!

Our forecast remains essentially unchanged for the next few days, although we have done a little fine-tuning. We’ll ‘up’ the rain chances for Wednesday afternoon at tad -- to 40% -- with scattered showers and isolated t-storms for Hump Day. Set rain chances at 50% to 60% (scattered showers & t-storms) for Thursday afternoon and evening. Expect mainly-dry mornings for Wednesday and Thursday with patchy fog possible both mornings and sunrise temperatures in the low 70°s for metro BR. Afternoon highs will climb into the upper 80°s for most communities on both days before the afternoon rains arrive.

We still think that Friday’s cold front reaches the WAFB viewing area on Friday morning, although we may tweak the timing by 3-6 hours between now and Thursday evening. We’re planning for “rains and storms likely” by early Friday morning as the front approaches the viewing area. Plan on widespread rains and thunderstorms for Friday morning just ahead of the front -- depending on the exact timing, Friday morning’s commute could be a real weather-enhanced mess. Although we can’t completely rule out one or two strong to severe storms as the front moves by, we are not concerned about this developing into a significant severe weather event.

The way it looks right now, the front should push steadily to the southeast on Friday with only limited rains on the “backside” of the boundary -- in other words, the rain should wind down quickly once the front moves through. With a little luck (and again, depending on how the final timing shakes out), not only will the rains end by or before mid-day but skies could begin clearing by Friday afternoon -- just in time for high school football and BR’s downtown ‘Live After Five.’

We get the big payoff for Friday’s front over the weekend: clear and cool mornings for Saturday and Sunday and sunny skies with mild temperatures and considerably lower humidity for the afternoons. And for now at least, we’ll keep the weather dry and agreeable into the middle of next week.

Monday, September 29, 2014

Staying Warm & Muggy on Tuesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- isolated showers on Tuesday, isolated-to-scattered rains for Wednesday
- humidity stays elevated with highs in the upper 80°s for Tuesday thru Thursday
- waiting for a cold front to arrive on Friday

As we had anticipated on Sunday, today was a muggy day but many WAFB communities stayed dry. Dew point temperatures in the low 70°s gave it almost a summer feel in terms of humidity … but the clouds kept afternoon high temperatures in the mid 80°s for most WAFB communities. For many of us, passing mid-day and afternoon showers were little more than a nuisance where they did develop.

A weak trough of low pressure still lingers along the northern Gulf Coast: the National Weather Service is “painting” it as a quasi-stationary front. Regardless of how you label it, the air is muggy on both sides. Pockets of rain continue to develop along and near the boundary: motion on the north side is mainly from ENE to WSW while rains on the south side are generally moving west-to-east. But the main story here is that the more significant rains have moved well to our east with only isolated showers impacting southern Louisiana and SW Mississippi.

The trough/front will stay in place for Tuesday and Wednesday. Like today, the primary action will be far to our east but we can’t rule out a few showers over the course of the next two days. We’ll go with spotty to isolated showers for Tuesday (rain chances under 20%) and then call for a 20% to 30% rain chance for Wednesday. Morning starts for both days will be around 70° to the low 70°s for metro Baton Rouge with afternoon highs in the upper 80°s under partly-cloudy to partly-sunny skies.

Headed into Thursday, the air mass over us becomes a little more unstable as we await the arrival of a cold front on Friday. Set rain chances on Thursday at 50% or better for the afternoon and evening with rain likely through the overnight and into Friday morning. Our latest guidance suggests that Friday’s front arrives in the WAFB viewing area sometime close to sunrise on Friday but should steadily push to the south and southeast through the middle of the day. That could mean a rather wet and messy morning commute for Friday; however, if that timing pans out, we can expect some improvement by/before the evening drive home. At this point we are not anticipating a significant severe weather event but we could see a few stronger storms develop just ahead of the advancing front. Frankly, it’s still a little too early to assess the overall severe weather threat, so we’ll keep an eye on the potential as the week progresses.

The payoff arrives by Saturday morning with all indicators pointing to a fine weekend: cooler mornings, low humidity during the day and plenty of sunshine for Saturday and Sunday. Those along and north of the I-10/12 could see lows close to 60° or so for Saturday’s sunrise with Sunday morning lows falling into the mid to upper 50°s for most WAFB neighborhoods. Highs for both days look like the low 80°s for metro Baton Rouge -- fine early fall weather.

In the tropics, an area of low pressure west of Bermuda -- labeled as Invest 97L -- has a good spin and solid organization based on satellite presentation but remains short on convection. Given 97L’s current lack of thunderstorm activity and the expectation for enhanced shear in the coming days, the system is given only a slight chance (about 20%) of becoming a sub-tropical or tropical storm in the next couple of days according to the National Hurricane Center. Still, Bermuda residents need to keep an eye on the situation; but for the U.S., regardless of what becomes of 97L, it appears destined to stay out over the Atlantic and head north and then northeast towards ever-cooler waters. Elsewhere in the basin, all remains relatively quiet.

Thursday, September 25, 2014

Staying Dry on Friday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- warm & dry for Friday
- slight rain chances for Saturday
- better rain chances for Sunday
It was a fairly nice day today: mostly sunny skies for most of the day and dew point temperatures running in the low 60°s for metro Baton Rouge.  You may have noticed some high, thin cirrus clouds moving into the viewing area this late afternoon, but those are nothing to worry about.
Our forecast for Friday calls for another nice early autumn day with sunrise temperatures for Baton Rouge once again in the mid 60°s under mainly-clear skies.  The afternoon will feel a little warmer, with highs in the upper 80°s and a slight increase in low-level moisture (more humid ‘feel’ to the air) under partly cloudy skies.  But we expect few if any complaints by the late afternoon and evening: looking good for Friday’s ‘Live After Five’ and high school football across the viewing area.
Our forecast for Saturday looks a little better today than it has for much of the week.  We’ll start the day under fair to partly cloudy skies with sunrise temperatures across metro BR in the upper 60°s.  Cloud cover will increase through the day, but we’re less concerned about a “wet” afternoon than in previous forecasts.  Earlier in the week we were calling for scattered afternoon and evening showers across the WAFB viewing area, but the latest indicators now suggest only isolated rains for the afternoon and evening.  That’s good news for Tiger Tailgaters and everyone else hoping to enjoy some outdoor time. 
The models are still differing on the rain coverage over the weekend, especially for Sunday.  The models agree on the development of an area of rain that moves into the Gulf Coast states over the weekend, but “where?” is the question.  Some of the guidance brings it into Louisiana during the latter half of the day on Saturday, while other models suggest that most of the rainshield moves inland to the east of our viewing area, keeping us more dry than wet, especially for Saturday.
For now, we’re keeping rain chances for Sunday at about 50-50 or so for the viewing area.  Unlike Saturday, rains could develop on Sunday morning and continue in an “on-and-off” pattern through much of the day before tapering off towards the evening.  We’ll keep a slight chance of rain in the overnight and early Monday forecast, with fair to partly cloudy skies for the better part of Monday.
Lows will run in the upper 60°s to near 70° through the weekend and into next week with afternoon highs in the upper 80°s each day.
And nothing of any real concern in the tropics.

Wednesday, September 24, 2014

Mainly Dry Through Friday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- no complaints about today’s weather
- staying dry for Thursday & Friday
- rain chances on the rise into the weekend

Just a tad warmer and more fair-weather clouds today: you also may have noticed a slight uptick in the humidity today compared to Tuesday … but it would still be hard to complain about today’s weather, the second full day of autumn.

Our forecast for Thursday and Friday will reflect a modest increase in low-level moisture over the next few days, although we may get a brief, weak surge of reinforcing drier air tomorrow to keep things relatively nice. Most metro area neighborhoods can expect Thursday morning lows in the low to mid 60°s under mostly-clear skies and an afternoon high in the upper 80°s under fair to partly cloudy skies. Friday looks good too: fair skies to start in the day with sun-up temps in the mid 60°s for the Capital City and a dry afternoon under partly cloudy skies with highs in the upper 80°s once again.

Friday evening around the area will be just fine with so much to do, including area high school football, downtown’s ‘Live After Five’, and the kick-off for the Ascension Parish Balloon Festival at Lamar-Dixon Expo Center!

Of course, the good stuff can’t last forever … and our primary extended range guidance models are showing Gulf moisture moving inland over the weekend and delivering rains to the central Gulf Coast region. However, they are not in complete agreement regarding timing and extent of the rain coverage. For now, the American GFS model appears a little ‘drier’ than the European throughout the weekend, with both models essentially clearing things sometime on Monday.

Splitting the difference, we’ll call for a dry Saturday morning and go with scattered showers and isolated t-storms for Saturday afternoon and evening (rain chances at 30% to 40%). Both models show Sunday as the wetter of the two days: let’s go with scattered on-and-off rains through the day, with rain chances set at about 50% to 60% for your backyard. That said, our confidence with this weekend forecast is rather low right now -- we’ll wait another 24 hours or so to see if the models come into better agreement on the weekend solution.

As for the tropics, it remains extraordinarily quiet. There are at least four tropical waves marching form east-to-west across the basin, but most of the tropical region remains under the influence of moderate to strong shear, effectively blocking any potential for wave development. So far, the Gulf has only seen one ‘named’ storm -- T.S. Dolly -- and there have been no landfalls along the U.S. Gulf Coast since 2013’s T.S. Andrea hit Florida’s Big Bend (6 June 2013). 

Tuesday, September 23, 2014

Another Beauty on Wednesday!

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- another comfortably cool start for Wednesday
- stays dry through the rest of the work week
- rain returns to the forecast for the weekend
How about that for the first day of fall?  But sadly, don’t get used to it.  As expected, most of us started the day in the upper 50°s to low 60°s under clear skies.  Highs topped out in the mid 80°s for most WAFB communities under a ‘ton of sunshine’ with dew point in the 50°s -- that’s welcomed “dry” air (low humidity).
Skies remain clear tonight and into Wednesday morning; the Red Stick will enjoy another day with sunrise temps near 60°.  However, dew point temperatures will begin a slow rise by mid-day tomorrow.  Skies will remain mostly sunny with highs returning to the upper 80°s for most -- still a pretty day but just not quite as nice as today.
Our area forecast remains mainly-dry through Friday, with the humidity continuing a slow rise.  Morning starts will be in the low to mid 60°s for Thursday and mid to upper 60°s by Friday.  Highs for Thursday and Friday will be in the upper 80°s under fair to partly cloudy skies.  We can’t completely rule out a spotty shower by Friday but the chances are almost too low to even mention: set Friday’s rain chances at 10% for the afternoon and early evening.
Heading into the weekend, rain returns to the forecast.  For the time being, we’ll go with about a 40% chance of rain for Saturday and likely rains on Sunday.  The rains and clouds should keep just about everyone in the 80°s for weekend highs.  We’ll keep isolated to scattered rains in the forecast for next week’s start too.
In the tropics, there’s simply nothing to talk about.  The NHC has identified no areas with even a slight chance of development through the next five days -- and we don’t hear anyone complaining!

Monday, September 22, 2014

Beautiful Start to Fall on Tuesday!

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- cool sun-ups for Tuesday & Wednesday
- dry pattern sets-in through the work week with highs in the 80°s
- all quiet in the tropics
Although the afternoons were quite warm over the weekend with highs near 90° for most WAFB neighborhoods on both days, the humidity was agreeable making for nice afternoons.  In fact, about the only complaint most would have about the past weekend was the first half of LSU’s SEC home opener … but we’ll leave that discussion to the Sportsline guys.
Two things happen today:
(1) a weak cool front slid through the WAFB area, delivering isolated showers at best, and
(2) autumn officially begins this evening at 9:29pm CDT.
The cool front sliding through Louisiana lost much of its form: the air ahead of the front was already fairly dry so that the air-mass contrast was minimal.  IN addition, the dry air already over south Louisiana as the front arrived provided little instability for the boundary to work with as it pushed through.  As a result, the front tracked from north-to-south through the area producing very little shower activity on its way towards the Gulf.  However, dew point temperatures will display a large drop-off tonight, falling into the 50°s for most WAFB communities.  That should lead toTuesday morning lows in the upper 50° to low 60°s for those living along and north of the I-10/12 corridor -- the coolest readings since mid-May.
The work week forecast remains dry as a continental air mass (dry air from the north) settles in and remains over the region.  Lows will fall to the low to mid 60°s again for everyone on Wednesday morning and show a slow rise through the remainder of the week.  Tuesday will be the coolest of the four-day run, with metro area highs in the mid 80°s; highs for the remainder of the week will run in the upper 80°s.  But for now at least, we’re not anticipating any 90°s through the coming weekend.
So you may be wondering, “Are we done with the 90°s for 2014?”
It’s possible, but not likely.  Baton Rouge records show that roughly 3-in-4 autumns have at least one day with a high of 90° or more.  In fact, although not very common, there have been a number of years when there were ten or more days with highs of 90° or more after the fall equinox.  But we can be hopeful: the last time there were no 90°s after September 22?  Not that long ago: back in 2008.
What about the extended outlook for the coming weekend?  Guidance is hinting at a non-tropical low developing in the Gulf over the weekend, providing decent rain chances for both Saturday and especially Sunday.
As for the tropics?  Satellite views of the Atlantic Basin show a series of poorly-organized tropical waves, none of which are hinting at any potential for development, at least over the next several days.  The atmosphere over virtually the entire tropical Atlantic remains rather hostile -- no complaints there either!

Thursday, September 18, 2014

Drier Air Arriving on Friday

By Jay Grymes & Steve Caparotta

- drier weather for Friday and the weekend
- a little cooler by the middle of next week
We started the day with clouds, patchy fog and spotty showers along the coast as expected, but the morning drive was rather uneventful weatherwise for most WAFB communities.  For the afternoon, our warm-and-moist Gulf air mass kept most of us under the clouds while we watched a broad (non-tropical) disturbance over Texas slide towards the southeast into south Louisiana.
That disturbance was running into a layer of somewhat drier air at the lower levels across the southern parishes, holding the afternoon rain potential in check for most of the viewing area.  However, as we get into the evening hours, we expect the disturbance to moisten the air sufficiently to generate some evening showers -- with a rumble or two of thunder possible as well.  What rains that do develop should generally fizzle out during the overnight hours.
We mentioned yesterday how difficult it has been to define the precise location and movement of a rather poorly-defined front that has been in play over the lower Mississippi Valley for the past few days.  That pesky boundary appears to be just about ready to slide southward and it likely dissipates as it does.  This should allow a drier (less humid) air mass to move over the WAFB viewing area - - just in time for the weekend.
We’ll keep spotty showers in the coastal forecast for the early morning hours and add in a little light, patchy fog for the Friday morning commute and bus-ride, but most of us start the day on the dry-side with sunrise temps for the Red Stick running around 70° or so.  Friday highs will edge up to around 90° for metro Baton Rouge under fair to partly-cloudy skies.  While we can’t say “absolutely rain-free” for Friday afternoon, we’ve got spotty showers at best for the afternoon and evening: great news for ‘Live After Five’ and high-school football fans!
The weekend remains mostly-dry as well, with rain chances at a very modest 10% to 20% for Saturday and Sunday.  Morning lows for both days will run in the upper 60°s to low 70°s across the viewing area with afternoon highs around 90°.  Dew points should generally stay in the 60°s for most WAFB communities through the weekend -- not quite “autumn-like” but still relatively comfortable by late summer standards.
It looks like the weather gets a bit more interesting next week.  Over the past few days we’ve been talking about a cool front arriving in the region during the early part of the week.  We’re still tweaking the timing of its arrival, but for now it scheduled for a Monday passage through our viewing area.  So two questions remain:
(1) Will it be a significant rainmaker? and (2) Will it deliver our first “touch of fall”?
As for being a rainmaker, the extended range guidance is a bit mixed, but early indications are that we can expect scattered rains, at most, as the front pushes through.  This is not uncommon with our fall fronts.  When dealing with often-stormy spring-season fronts, there is usually a big difference (a steep gradient) between temperatures and moisture content on either side of the front: warmer-and-moist Gulf air on the south side, much cooler-and-less-humid continental air on the north side.  During the fall, however, these temperature and moisture differences across the frontal boundary tend to be less pronounced.  The ‘weaker’ gradients across a fall front typically translate into less lifting energy … and it is the lifting energy that generates frontal thunderstorms.
So for now, we’ll go with rain chances running about 30% or so for Monday as the front cuts across the viewing area and continues south into the Gulf. 
You’ll see that we have isolated rains in the Tuesday and Wednesday forecast: that will largely depend on how far south the front moves.  We’ll fine-tune that outlook as we head into the weekend but our suspicion is that both days will be dry ones, at least for the northern half of the WAFB region.
And what about a “taste of fall” on the backside of the frontal passage?  More like a “tease” than a “taste”: you will notice a drop in humidity and the temperatures will drop a bit too, but don’t be thinking sweaters and blankets just yet!
In the tropics, we continue to track the Atlantic’s Edouard.  The current National Hurricane Center (NHC) forecast keeps Edouard “alive” into the weekend as he heads east into ever-cooler waters.  Residents of the Azore Islands will want to keep an eye on ‘him’ but Edouard’s days are numbered.  The NHC is also watching a tropical wave that is moving into the eastern Atlantic off the coast of Africa, but that disturbance is simply too far away for our concern.

Wednesday, September 17, 2014

Somewhat Better Rain Chances on Thursday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- sct’d t-showers back in the forecast for Thursday
- looking mainly-dry for Friday & Saturday
- no Louisiana threats in the tropics
Today proved to be close to rain-free across the WAFB area -- admittedly a bit of a surprise for us.  The atmosphere was certainly moist enough to support afternoon rains but it may simply be that the day’s cloud cover slowed the afternoon warm-up just enough to keep from reaching the “temperature trigger” (often called the convective temperature) required to get the afternoon action going.
For most of us, there was no complaining about a day without rain!
We don’t expect to be as lucky tomorrow.  Plan on patches of light fog and a spotty shower or two closer to the coast for Thursday’s morning drive.  After a morning start with sunrise temperatures in the low 70°s for metro BR, our forecast calls for scattered showers and a few t-storms for Thursday afternoon under a sun/cloud mix.  We’re posting rain chances for Thursday afternoon in the 30% to 40% range, which means that the majority of neighborhoods will stay dry, but be umbrella-ready just in case.
Friday’s forecast continues to improve with only spotty showers in the afternoon forecast: good news for ‘Live After Five’ and high school football.  And Tiger fans should be happy with the Red Stick forecast for Saturday: only a 20% rain chance, at most, for the afternoon hours.
We’re still trying to get a handle on the diffuse, meandering front that lingers over the southern states.  That front is still to our north, keeping us under the influence of Gulf moisture and accounting for our continued summer-like humidity.  We expect the front to continue to sag southward through the rest of the work week, passing through the BR metro area during the first half of the day on Friday and heading out into the northern Gulf by early Saturday.  That scenario delivers slightly ‘drier’ (less humid) continental air for Friday and into the weekend, resulting in our ‘drier’ forecasts for Friday and Saturday.  Unfortunately, we expect the front to stall, at least temporarily, near the coast on Saturday into Sunday, keeping it close enough to allow for slight rain chances for Saturday and Sunday.
Our next cool front slides through the U.S. Plains early Sunday on its way to the Gulf Coast.  Its advance looks to be a little slower today than it did yesterday, but we still expect it to arrive in our viewing area during the latter half of Monday or very early Tuesday.  However, the latest guidance also hints at that front stalling close to the coast, so it may not deliver the “real fall feel” that we were hoping for.  However, all that is well down the road: let’s see how it shapes up later this week. 
And in the tropics, there is nothing of any concern for Louisiana and Gulf regional interests.  In fact, the entire basin can take a breather – no tropical waves offer any real threat of development at this time.  As for Hurricane Edouard, ‘he’ is well out to sea and headed ENE … and will likely be downgraded to a tropical storm within the next day.

Tuesday, September 16, 2014

Less Rainfall on Wednesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- scattered rains for Wednesday & Thursday
- ‘drier’ for Friday and Saturday
- Edouard becomes the season’s first ‘major’ hurricane
We had to wait until about 1:00pm, but as predicted yesterday, the rains arrived for most WAFB neighborhoods this afternoon.  Radar trends suggest two features at work today: a northbound “sea breeze” front and a southward-sagging band of showers and storms that extended along a west-to-east line from Avoyelles and St. Landry parishes into the eastern Florida Parishes.  Although none of the storms proved ‘severe’, a number were highly-charged with frequent cloud-to-ground lightning, produced locally-heavy downpours and generated some noteworthy wind gusts.  We even received a report of small hail during the early afternoon from the Springfield area (Livingston Parish).
Heavy downpours prompted the NWS to issue a FLASH FLOOD WARNING from approximately 4:00-5:45pm for portions of Ascension, Assumption, Iberville and St. James parishes.
This activity will taper-off into the evening hours, but we expect to see lingering showers -- and possibly a storm or two -- into the late evening.  We’ll carry spotty showers into the Wednesday morning forecast, mainly for areas closer to the coast.  Look for Wednesday sunrise temperatures in the low 70°s for metro Baton Rouge with some pockets of mainly-light fog to accompany the AM commute. 
We expect some rain for Wednesday afternoon but with the percentages set at only 30% -- not the widespread activity like we saw today.  Plan on a sun/cloud mix through the afternoon with temperatures getting up into the low 90°s for many WAFB communities.
Thursday starts with spotty morning showers again and lows in the low 70°s for the Red Stick.  Set afternoon rain chances for Thursday at 30% to 40% with highs in the upper 80°s to around 90° for most WAFB communities.
The fact is, the entire forecast for the next several days remains a little unclear.  We continue to struggle with defining the forecast positions in the next few days of a cool front that separates the warm-and-muggy Gulf air mass currently over us from a cooler-and-less-humid air mass to the north.  Our current thinking has the front meandering somewhere over Louisiana through Thursday before finally sagging south towards the Gulf on Friday. 
Our Friday forecast shapes up to be a pretty good one as does the outlook for Saturday: fair to partly cloudy skies with isolated showers for both days.  Depending on the front’s position, both days could be essentially rain-free with a nice dip in the humidity -- but we’ll have to wait another day or so to see how this pans out.
After that, our next cool front begins to approach south Louisiana from the Plains on Sunday -- guidance suggests that it reaches the state sometime on Monday.  We’ll call for a 30% rain chance for Sunday as the air mass ahead of the front becomes more and more unstable, then go with a 50-50 rain chance or better for Monday. 
Could next week’s front be that “first fall front” suggesting an end to summer heat?  It’s possible, but let’s wait a couple of days to see if next week’s weather picture comes into better focus before we start celebrating!
In the open Atlantic, Edouard was upgraded to a ‘major’ hurricane (Category 3) as of 10:00am this morning -- not just the first ‘major’ hurricane of 2014 but the first ‘major’ since 2012’s Sandy.  But Edouard has already weakened and been downgraded as of 4:00pm to Category 2.  Beyond that, there are no significant changes to the basic track forecast for Edouard, with the system expected to turn more to the NE and stay over the ocean.  The latest forecast suggests that Edouard will continue to slowly weaken but could hold on to hurricane strength into Thursday before succumbing to the cooler waters of the north-central Atlantic.

Monday, September 15, 2014

Good Rain Chances on Tuesday

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- a ‘wet’ Tuesday likely for the WAFB area
- no tropical threats for the Gulf region any time soon

We had a 2” downpour here at the WAFB studio earlier this afternoon, most of it falling between about 1:30-2:30pm. While radar was ‘lit up’ around the immediate metro area from about 1:00-3;00pm, the majority of WAFB communities managed to stay dry through the day. However, as of 4pm, we’re still tracking some action, especially south of the Capital City. The atmosphere across our viewing area remains rather juicy, so we’ll keep spotty showers in the overnight and morning forecast. That means “mostly dry” for the morning drive and school bus ride on Tuesday, with lows around sunrise in the low 70°s for metro BR. 

Rain chances will increase as the day progresses, so the question becomes: “Just how widespread will it be?”

We admit to getting mixed signals from the models on the rain coverage for Tuesday, with rain percentages running from roughly 40% to as high as 80%. We’ll split the difference for now and call it 60% or so for the afternoon -- in other words, “showers & t-storms likely.” The rain and clouds should keep Tuesday’s highs in the mid to upper 80°s for just about everyone, with the rains tapering off into the evening. We’re carrying spotty showers in the late Tuesday night/Wednesday morning forecast with rain chances rising to about 40% for Wednesday afternoon.

A frontal system to our north is headed our way and appears that it reaches the WAFB area on Wednesday – plan for scattered showers and storms for Wednesday afternoon. The front may slow a bit as it continues south and again the model guidance isn’t in agreement as to what happens for Thursday and Friday. For the time being, we’ll set rain chances at 30% for Thursday and 20% for Friday, but we do so with somewhat low confidence. If the front can push far enough south, both days could become fair-weather days.

Expect lows near 70° to the low 70°s for metro BR just about all week long, with highs in the upper 80°s to near 90°. Headed into the weekend, we’ll call for 30% rain chances for both Saturday and Sunday, with highs in the upper 80°s to near 90°. And in the extended, the guidance is hinting at another cool front early next week.

We’re still tracking a very strong ‘Category 2’ Edouard, moving NW to NNW over the open Atlantic. The latest NHC forecast calls for Edouard to continue to intensify, becoming a Category 3 hurricane later today or tomorrow - - the first ‘major’ hurricane of the 2014 season. Fortunately, Edouard will remain well to the east of Bermuda, which means no threats to land as we await the expected turn to the north and then NE. Meanwhile, in the eastern Pacific Basin, Hurricane Odile continues to spin over the Baja (California) Peninsula and is expected to remain over land for the next day or so. Remnants of Odile (likely a depression by or before Wednesday) could reach the U.S. Southwest later in the week.

Thursday, September 11, 2014

Scattered Rains into the Weekend

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:
- even better rain chances for Friday & Saturday
- a new Tropical Depression … and watching the invest to the east of Florida
Our run of mostly-dry days has ended.  Scattered rains this afternoon will give way to even greater coverage tomorrow as the cool front we’ve been talking about makes its way into northern Louisiana then slows to a crawl.
With the front drawing closer and a steady inflow of moisture off the Gulf, we’ve got the set-up for a rather wet Friday afternoon: not the best news for Baton Rouge’s ‘Live After Five’ nor area high school football.  While Friday will start-off mainly dry, we’ll go with scattered-to-likely showers and storms for Friday afternoon (50% or so).  And unfortunately, scattered rains linger into the evening hours too.
Set sunrise temps for Friday in the low to mid 70°s for metro Baton Rouge under partly cloudy skies.  As we’ve seen just about all week, we could see a few patches of mainly-light fog for the morning commute as well as a spotty shower or two, but it should be a mostly dry start to the day for just about all WAFB communities.  Temps for most neighborhoods will still reach around 90° or so during the day before the clouds and rains kick-in.
Saturday?  Not much better.  In fact, we’re carrying isolated showers in Saturday’s morning forecast with roughly 50-50 rain chances for the afternoon.  The cool front over the state will slowly sag southward during the day, serving as a lifting mechanism to support rains.  However, clouds and rain should keep daytime highs in the 80°s for Saturday, but it won’t be a good day for pre-game tailgating for the Jags on the Bluff, around Death Valley for the Tiger faithful, nor down in the Crescent City for the SLU Lions. 
By Sunday, we think that the front will be meandering near the coast and over the coastal waters.  Backside clouds will still keep things mostly cloudy, but rain chances should drop a bit.  With a little luck, communities north of the I-10/12 could see lows slip into the upper 60°s by Sunday’s sunrise.  We’ll set rain chances for Sunday at about 40% -- greatest closer to the coast -- with highs again topping out in the upper 80°s to maybe near 90°, depending on how much sunshine your neighborhood gets.
For next week, we keep scattered mainly-afternoon rains in the forecast for just about every day.  Morning starts will be near 70° to the low 70°s and afternoon highs return to the upper 80°s to near 90° each day.  So we do expect a modest dip in the daytime temperatures compared to this week … but still nothing “fall like” in the short-range.
In the tropics, we’re watching two features.  Earlier today, the National Hurricane Center (NHC) upgraded Invest 91L to Tropical Depression #6.  The NHC forecast calls for T.D. #6 to become T.S. Edouard in the short term with the system potentially reaching hurricane status within the next five days.  However, the key to this tropical story is that whatever T.D. #6 becomes, it should remain over the open Atlantic and pose no threats to land.
Closer to home, we continue to watch the low-pressure ‘blob’ to the east of Florida, Invest 92L.  92L is looking rather ragged today, with its convection well-separated from the apparent low-level core due to persistent northeasterly shear.  What’s more, all indications are that the shear remains in play through the next couple of days, at least, as 92L slowly tracks to the west or WSW across the Florida peninsula.  That shear is a main reason why the NHC canceled the scheduled aircraft recon earlier today and why they are keeping development chances on the low side (only 30% through the next five days).
Virtually all of the model guidance has 92L moving into the eastern Gulf by Saturday morning … and that is getting everyone’s attention (as it should) … with several models taking the system towards the central Gulf Coast early next week.   However, most of the models are also indicating that the shear will continue to play havoc with the system and limit any real opportunity for intensification.
That said, we’ve seen it before: things can change in a hurry.  There is no need for concern at this point … we are far from any kind of serious threat.  However, with the weekend approaching, now is the time to evaluate your personal, family and business preparedness plans.  Get everything ready BEFORE a potential threat develops.
Want some help to get ready or fine-tune your current readiness?  It’s never too late to become better prepared.  Check out: 

Wednesday, September 10, 2014

Rains Returning to the Forecast

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- afternoon highs in the 90°s continue through Friday
- increasing rain chances from Thursday into the weekend
- no Louisiana threats in the tropics

Just about everyone stayed dry today as expected, with only brief spotty rains developing over the WAFB area. Look for any lingering activity to subside around sunset. We’ll stay dry again through the night and the morning, with mostly fair skies and a few patches of mainly-light fog for the Thursday morning commute. Sunrise temps for the Red Stick will be in the low to mid 70°s. For Thursday afternoon, the weak high-pressure lid on the atmosphere that kept most dry today weakens at tad, allowing for a little greater cloud coverage and ultimately a 20% to 30% coverage of showers with a few rumbles of thunder. Highs for Thursday will again reach the low 90°s -- and “feel like” 98° to 103° for many neighborhoods in terms of peak afternoon Heat Indices.

Unfortunately, there is no improvement in the wishful thinking of the approaching “cool” front: as we feared, the guidance is now suggesting that the front may not even make it as far Baton Rouge before Friday evening. And after that, it is expected to stall along or near the southern parishes for the weekend: so much for our hopes of a “taste of fall weather” for the weekend.

Friday starts out mainly-dry with sunrise temperatures in the low to mid 70°s. Highs for many WAFB communities will reach 90° or above for the afternoon, but we’re going with scattered showers and t-storms for Friday afternoon and evening -- not great news for this week’s downtown ‘Live After Five’ or Friday night high school football. But we do expect the rains to subside a bit as we head into the evening hours, so we can hope for a decent evening.

The front is then expected to slowly sag southward for Saturday and Sunday, serving as a rain enhancing feature for the weekend. Yes, highs will far short of the 90°s over the weekend for many WAFB communities, but the reason will be more about the clouds and rains than the result of a changing air mass as the front slowly slips by. Set rain chances for Saturday at 50% or better, then around 40% or so for Sunday.

LSU, Southern and Southeastern football fans will once again be encouraged to tote the rain gear for gameday festivities, especially for the pre-game tailgating. With a little luck -- like all three campuses had last week -- game time conditions should be at least a bit more agreeable.

The outlook through the first half of next week keeps scattered mainly-afternoon showers and t-storms in the regional forecast, with lows near 70° and highs in the upper 80°s to near 90° for Monday through Wednesday.

In the tropics, the National Hurricane Center (NHC) is still tracking Invest 91L in the east-central Atlantic. 91L hasn’t shown any real development over the past 24 hours but it still has some potential to become our next tropical cyclone (a depression or tropical storm) down the road - - the NHC currently posts 91L with a 70% chance for cyclone development in the next five days. Regardless, the early forecast guidance appears to keep 91L over the open Atlantic regardless of what development may transpire.

The NHC also upgraded the area of low pressure centered near the Bahamas: by “upgrade” we mean declaring it as an invest (Invest 92L). Development potential -- still posted at just 20% over the next five days as of 2PM -- is likely to be increased later this evening given the latest satellite presentations. Remember, when the NHC defines a disturbance as an “invest,” it sets more extensive tropical analyses into motion, not just with the NHC experts, but also with a number of supporting agencies and university research groups. Look for “spaghetti model plots” to begin arriving over the coming hours with the forecast consensus likely taking the system (whatever it becomes) into the eastern Gulf. Stay tuned …

Tuesday, September 2, 2014

Little Change This Week...

By Jay Grymes & Steve Caparotta

WAFB First Alert Quickcast:

- maintaining that summertime ‘fell’ through the week
- watching T.S. Dolly head towards Mexico
Taking care of the tropics first . . . T.S. Dolly continues to head towards The Mexican Gulf Coast and should make landfall sometime overnight or early in the morning.  Dolly could intensify a bit before landfall, but the forecast keeps ‘her’ as a moderate tropical storm when ‘she’ cross the coastline.  Dolly is the first ‘named’ storm of the 2014 season for the Gulf of Mexico ... and the first ‘named’ storm of 2014 not to reach hurricane strength.  Elsewhere in the Atlantic Basin, there are no areas of immediate concern.
Back closer to home, it may be a new month but it still feels like summer.  But remember, it is supposed to, especially in the Deep South.  Summer doesn’t officially end for almost another three weeks (on Sep 22), and it is not rare to have some hot days in the first half of the month.  In fact, the longest consecutive stretch of 100° days for Baton Rouge occurred from August 20 to September 5 (7 days) back in 2000 - - there is no other run of more than 4 consecutive days at 100° or more, at least since 1930.
We’re not expecting much of a chance in our outlook for the rest of the week and into the weekend.  If anything, it may get a little ‘wetter’ than what we saw today.  We’re going with rain chances at around 40% t0 50% each day right into next Monday - - with most of the rain being the summertime afternoon variety.  And in keeping with the summer season, morning lows wil be in the low to mid 70°s for the Red Stick with afternoon highs in the low 90°s.
Bottom line: no relief from the summer heat just yet.
But this is a transition month -- no doubt about it – as Baton Rouge normals take a big step down during the four week period.  While normal highs at the start of September are in the low 90°s, they drop to the mid 80°s by month’s end.  And the daily low normals slip from summer-like low 70°s down to comfortable mid 60°s.  Yet maybe the biggest weather story in most Septembers is the welcomed arrival of the first real autumn front.  (Okay, that is the biggest September weather story as long as the tropics are behaving.)
So keep the A/C on high for now .. and with some weather luck, we’ll have a run of days in the coming months when we can shut it off and open the windows!