Monday, September 30, 2013

More Rain Likely This Week

Most made it through the weekend without any rain although we’ve seen scattered to numerous showers and a few t-storms rolling through the viewing area today. While there have been pockets of off-and-on light showers for much of the day, the more significant rains came in two waves: one early in the day and a another with some embedded t-storms in the late afternoon.
We’ll keep numerous showers and occasional t-storms in the forecast for Tuesday (rain chance at 60%), do it again for Wednesday, and then keep the local weather “unsettled” into the weekend. What do we mean by “unsettled?” Plan on scattered rains -- especially during the afternoons – for Thursday and Friday, with rain likely again on Saturday.
A stalled front to our northwest and west will just sit there, eventually fizzling out on Tuesday. While that front won’t move through our area, it has enhanced the flow off the Gulf which means plenty of low-level moisture for the Bayou State. At the same time, it is close enough to add to the daytime instability, especially when we add in the effects of modest afternoon heating. Another ingredient that will be a player on Tuesday and Wednesday will be the occasional west-to-east passage of mid-level disturbances -- these are “weaknesses” in the mid-levels that appear as large pockets of rains moving through the region, much like what moved through the lower Mississippi Valley earlier this morning and then again in the afternoon.
Like today, Tuesday’s and Wednesday’s rains and clouds will keep afternoon highs in the mid 80°s for many of us. However, as rain chances decline later in the week, we can expect highs to return to the upper 80°s by Thursday and Friday. Since the front to our west will fizzle out where it currently stands, we’ll get no “dry out” in terms of reduced low-level humidity and a drop in dew points, so lows will stay in the upper 60°s to low 70°s for most WAFB communities right into the weekend. (Remember, the minimum temperature cannot be lower than the dew point temperature.)
Guidance is currently showing our next cool front moving into the viewing area this upcoming weekend. We’ll watch for adjustments in the forecasted timing of that weekend front over the coming days. For now, we’ll call for the weekend front to get through our viewing area late Saturday or very early Sunday, allowing for a decent Sunday with cooler air and noticeably lower humidity.
In the tropics, a broad, poorly-defined area of low pressure sits over the west-central Caribbean -- labeled as “Invest 97L.” As of this afternoon, the National Hurricane Center (NHC) gives this disturbance only a 30% chance of becoming a tropical cyclone over the next five days as it moves towards the northwest. Although uncertainty abounds, the long-range outlook suggests a better environment for the low-pressure area as it enters the southern or southwestern Gulf -- this could encourage some development. We’ll keep an eye on it over the coming days but, frankly, given its current poor shape, there’s really no reason to become too concerned, at least for the time being. Let’s wait and see what we have into the weekend.
The NHC is also tracking Tropical Storm Jerry, located in the central Atlantic. The NHC “upgraded” Tropical Depression #11 earlier today to T.S. Jerry, the 10th named storm of the Atlantic Hurricane Season. The current NHC forecast for Jerry keeps the storm over the open Atlantic and eventually track off to the northeast, offering no threats of landfall.


Saturday, September 28, 2013

Southern Forecast

Wet weather will not be an issue for the big game between Jackson State and Southern.  It will be quite warm especially just before the game for all you tailgaters.

Highs will remain in the upper 80°s near 90°, but when you factor in the humidity temperatures will actually feel more like the mid 90°s.  There won't be much shade from the soon in the form of clouds as skies remain mostly sunny to fair.  Be sure to dress accordingly and drink plenty of water if you plan to be outdoors for an extended period of time.

Kickoff is scheduled for 6 PM.  Temperatures even during this time will be in the mid 80°s.  Temperatures will fall pretty steadily once we go into the night time hours.  The weather is expected to remain dry through the entire game.  Finally go Jags!!!!

Thursday, September 26, 2013

Warm & Dry through the Weekend!

How about that morning start? Low to mid 60°s for many of us sure felt good under pretty blue skies. Yes, there may have been a few pockets of light fog in the greater metro area with areas of denser fog for several coastal parishes, but for most of us there were no problems for the morning drive.
Today’s highs reached the low 90°s for many WAFB neighborhoods as expected, but we enjoyed dew points staying in the low to mid 60°s through the day -- “drier” (less humid) than normal air even for September -- so the daytime warmth didn’t quite deliver that mid-summer feel.
Skies will stay mainly clear through the evening and overnight, with Friday morning lows expected to slip into the mid 60°s for metro Baton Rouge.
Plan on plenty of sunshine for Friday too. A few fair-weather clouds will develop as the winds work around to the ESE and SE by the afternoon, meaning a slow return of low-level Gulf moisture and a modest climb in the afternoon and evening dew points. Friday’s highs will return to the low 90°s again for most WAFB communities and the humidity will still be on the low side, so you can expect a warm but reasonably comfortable Friday evening around town or in your backyard.
And here’s more good news: we’re taking rain out of the forecast for Saturday and Sunday too. Sure, a spotty blip on Titan9 Doppler can’t be ruled-out over the weekend, but there’s not going to be enough rain anywhere in the viewing area to talk about. Highs both days will be up around the 90° mark and I think dew points stay in the upper 60°s -- not quite as “dry” as what we’ve enjoyed the past couple of days, but not getting too uncomfortable either.
Over the past couple of days, I’ve talking about a frontal system headed our way from the Pacific Northwest. In Wednesday’s extended outlook, I had the front arriving in our area on Monday producing scattered showers and t-storms. Our latest guidance suggests that the timing still looks about right but the system’s main upper-level support will be well to our north. In this ser-up, the front may not be as energetic as I previously thought. For the time being, we’ll keep scattered showers in the forecast for our Monday/Tuesday window and keep an eye on how the models evolve this system over the coming days.
And in the tropics, there’s not much to talk about. A large tropical wave in the central tropical Atlantic is advancing towards the west. Although it may be somewhat impressive in terms of its overall size, it currently shows little potential for development, at least over the next few days. For now, the National Hurricane Center gives the wave virtually no chance for development over through the weekend and only a 20% chance over the course of the next five days.

Wednesday, September 25, 2013

Enjoying the low humidity!

Overnight temperatures dropped more quickly than we expected for many neighborhoods, causing the air temps and dew points to pair-up right after midnight. Remember, when the air temp and dew point are the same, the air is saturated. Add in little or no wind and you get pockets of dense fog that some of you had to deal with during the morning drive.
Dew points continued to fall through the day, so that even with Wednesday afternoon highs reaching the upper 80°s to low 90°s for most communities, it felt pretty good outside through the afternoon. And the air will continue to “dry” (falling dew points) into the evening and overnight. That should allow lows to drop into the low to mid 60°s around metro Baton Rouge on Thursday morning, with some WAFB communities along and north of the LA/MS state line possibly recording some upper 50°s. Yep -- feeling a little fall-like!
We could see a patch or two of fog for Thursday morning, but we are not expecting anything like what some of you saw early Wednesday.
The weather stays fair and dry into the weekend, with highs for Thursday through Sunday running near 90° or so each day. Thursday should be another beauty. By Friday afternoon, the winds will have swung around, coming out of the east and southeast. That will mean a return of low-level Gulf moisture (increasing humidity), but not enough to become uncomfortable nor to fuel afternoon showers. So you can plan on a good looking Friday evening for high school football, “Live After Five” in downtown BR, or for a trip to Gonzales to see the evening balloon-glow and lift-off at the Balloon Fest at the Lamar-Dixon Center.
Saturday stays dry too, although by Saturday afternoon we’ll have a near summer-feel to the air with dew points closer to 70° and highs at or above 90°.
Our rain forecast for Sunday also continues to decline: the latest extended guidance suggests that our next cool front will be slower to arrive than we previously thought. In addition, the latest guidance suggests that next week’s front -- now scheduled for arrival on a Monday/Tuesday time frame -- may not be as energetic as originally thought. So for now, we’ll back down rain chances from “likely” to “scattered” with the approach and passage of the of the system early next week.

All quiet in the tropics ... in fact, there is hardly really only one notable tropical wave evident on the satellite loops. Given that this is September, the peak month for tropical activity, it is all but “dead” right now across the Atlantic Basin -- and no one is complaining!

Tuesday, September 24, 2013

Sunshine, Big Drop in Humidity for Mid-Week!

Passing rains in the early morning took a little punch out of the atmosphere for most of the area through the lunch hour but a quick warm-up combined with a “juicy”Gulf air mass provided the fuel for a second round of rains in the WAFB viewing area. Titan9 Doppler was showing scattered showers with a few embedded t-storms during the mid-to-late afternoon.
A warm front lifted to our north earlier in the day, allowing for a return of moist Gulf air over the region. The regional weather set-up also includes a non-tropical low in the northwestern Gulf, but that feature has not been much of a player today. At the same time, a Pacific cool front is entering the northwestern parishes this afternoon and evening and will continue to march our way overnight and into Wednesday morning.
We expect the main energy of the unstable Gulf air mass currently in place to shift to our east overnight. At the same time, the trailing end of the Pacific front slides through the viewing area on Wednesday, delivering a “drier” air mass with its passage. While we can’t entirely rule out a spotty shower or two along the coast for Wednesday’s morning drive, most WAFB communities can expect mainly fair skies for the morning drive.Wednesday afternoon is looking really good under clear skies. It will be “warmish” -- with highs running around 90° or so for many WAFB neighborhoods -- but dew points will drop into the low to mid 60°s for most of us by the afternoon. BR metro area lows will fall into the mid 60°s for Thursday morning with more sunshine and a “comfortably warm” Thursday afternoon on tap thanks to the “dry” air remaining in place.
Friday also stays rain-free under fair to partly-cloudy skies, but by Friday afternoon the winds will have come back around from the east-southeast, allowing for a return of some low-level Gulf moisture and a modest rise in dew points. Still, Friday afternoon and evening shape up to be the best we’ve seen in several Fridays, whether you’re headed out for some high school football, downtown’s “Live After Five,” or planning on watching the hot-air balloons in Gonzales.
Into the weekend? Saturday looks good too -- expect partly cloudy skies with highs in the upper 80°s to lower 90°s for most WAFB neighborhoods. We can’t say “no way” to a spotty shower or two on Saturday afternoon but with rain chances currently posted at just 10%, don’t let that affect your outdoor plans.
Even the Sunday outlook is shaping up better than it did yesterday. It’s all about the timing: we still expect our next front to be approaching on Sunday but the latest guidance suggests a slower advance. Based on the new projections, we’ll go with only isolated rains for Sunday afternoon and early evening, with increasing chances late Sunday into Monday as the front draws closer.
And there is absolutely nothing to report in the tropics. In fact, there are only two notable tropical waves currently over the Atlantic Basin and neither shows any potential for development at this time.

Monday, September 23, 2013

Wet Again for Tuesday, then the Sunshine Returns!

After the big rains on Saturday, Sunday’s dry-out was most appreciated -- and a day that also delivered an“autumn feel” to the first day of the new season!
Did you notice the deep-blue skies this morning? Unfortunately, the clouds moved in at mid-day and isolated to scattered rains returned to the WAFB viewing area this afternoon. The good news in all this rain is that we’ve taken a serious bite out of the dry spell that was threatening to become a full-blown drought.
The front that was responsible for Saturday’s rains stalled to our south but is lifting back to the north. It will stall along the central Gulf Coast and meander there through Tuesday and into late Tuesday and very early Wednesday. At the same time, a broad surface low over the western Gulf has linked up with the western end of the front. 
That western Gulf low is, in part, remnants of what was last week’s Invest-95L that threatened to become a tropical system off the Mexican Gulf Coast over the Bay of Campeche. Could “ex-95L” once again become a tropical threat? The mid-level shear is not very strong and the Gulf waters are certainly warm enough, so given the time of year it does bear watching. But the low is surrounded by dry air at the mid and upper levels and the system currently is clearly non-tropical. That combination has the National Hurricane Center giving the low virtually no chance of tropical development in the coming days.
Still, that low is expected to slowly track to the ENE along the front, likely moving along the Louisiana coast tomorrow. As a result, we push rain chances back into the “likely” category for most of the viewing area on Tuesday. With this set-up, many WAFB neighborhoods could see a half inch of rain or more, possible getting upwards to an inch of rain along the coast. But for those concerned about flood threats, not to worry: water levels have fallen enough over the past two days along our area waterways. Even widespread totals of an additional inch or more would not be enough to prompt flood warnings.
By early Wednesday, our next cool front will be approaching from the northwest. For the time being, at least, this does not look to be a very energetic front and it fizzles out as it passes by. But it should help drop dew points a couple of degrees late Wednesday into Thursday. Look for dry weather for the end of the work week with highs around 90 or so for Wednesday through Friday.
A slight chance of rain returns by Saturday, with the extended guidance showing a Pacific front potentially making for a wet Sunday.

Saturday, September 21, 2013

LSU Forecast

It looks like good news for LSU tailgaters and game goers.  A cold front is advancing through the area much faster than first anticipated.  This means drier and cooler air will work into South Louisiana as early as later this morning.
Doppler Radar Image @ 7:20 AM
 Taking a look at the Titan 9 Doppler Radar image above you can see that most of the heavy rain has pushed SE of Baton Rouge.  Notice the drier conditions just to the NW of Baton Rouge.  That is the current position of the passing cold front.  This won't result in a completely dry afternoon though.  A few lingering showers just in extreme East Texas near Lake Charles are proving that a few iso'd to sct'd light rain showers will still be possible later this morning and early this afternoon.  But the threat for heavy rain will not be an issue for LSU tailgaters.  Still have the poncho handy for some of these possible sct'd light rain showers.

As for the game itself the rain chance should really be minimal.  The field will be soggy I'm sure as rainfall totals have exceeded 3" in most Baton Rouge spots Saturday.

We can't rule out a few stray sprinkles here or there especially early, but the Tiger faithful will get to enjoy a mostly dry game.  The temperatures will be really nice too.  Cooler air on the backside of the front will but a nice fall like feel to temperatures.

Friday, September 20, 2013

Flash Flood Watch This Weekend

By Jay Grymes & Steve Caparotta

A FLASH FLOOD WATCH is in effect for the entire WAFB viewing area through Sunday evening.

Our wet Friday evening outlook already prompted downtown officials to cancel this evening’s “Live After Five” ... and for the third Friday in a row, at least a few high school games will be dealing with rains and storms this evening.

Although today’s rains and thunderstorms should ease-up later this evening, we’re keeping scattered rains in the WAFB regional forecast tonight with a forecast for a very wet Saturday morning. 

And the rest of Saturday is shaping up to be just plain wet too. 

We’ve got on-and-off rains throughout the day on Saturday with locally-heavy downpours likely, making for standing water and nuisance flooding across the viewing area. As it looks now, 2” to 4” rain totals could be commonplace through Saturday evening for the greater Baton Rouge area. Baton Rouge could then see up to another 1” of rain from Sunday into Monday. And for some areas -- especially closer to the coast -- event totals through Monday could be upwards of something closer to 6” or more!

As for Saturday festivities, we aren’t too concerned about a severe weather outbreak on Saturday but tailgating could be a real mess given the expected rains. And while we think scattered rains will continue into the evening, hopefully the lightning threat will decrease as the LSU-Auburn kick-off (at 6:45PM) approaches and that the game can start without any lightning delays.

Another change to our outlook calls for unsettled weather to extend into the early part of next week. We had hoped that the cool front that will prompt Saturday’s deluges would push out into the northern Gulf, but the latest guidance not only keeps a stalled front draped along our coastline through Tuesday but also hints that a non-tropical low could develop along the stalled front. (Somewhat interestingly, that surface low might be a part of the remnant energy from Invest 95L that we tracked for much of the past week.)

So, sadly, instead of three good looking days to start off next week, were’ keeping scattered rains in the forecast through Tuesday, at least.

Flood threats? As it turns out, our run of unusually dry weather over the past several weeks will work in our favor. Most area rivers and major bayous are running at “base flow” levels, in other words, they are at the lowest end of normal flow, and the environment is ready for a good soaking. So yes, there will be the nuisance street flooding and back-ups that we normally expect after a big rain event, but we don’t expect this to be a news-making flood event.

In the tropics ... Invest 95L just never got its act together, not that anyone is complaining. The National Hurricane Center still shows the poorly-defined disturbance just off the coast of Mexico, with most models allowing it to meander over the western Gulf over the next few days. As just mentioned, whatever is left of 95L could end up tying-in with our stalled front early next week.

Stay dry! And Geaux Tigers and Jaguars!

Thursday, September 19, 2013

More Wet Weather on the Way...

By Jay Grymes & Steve Caparotta

The viewing area saw scattered rains and t-storms with some locally-heavy downpours today and the action will be even more widespread by Friday afternoon.
We could see a few morning showers, but It should be a mostly-dry Friday morning drive under mostly cloudy skies.  The anticipated cool front we’ve been talking about over the past several days is approaching from the U.S. Plains and should be entering NW Louisiana by Friday evening.  Although the front doesn’t reach our viewing area until Saturday, a warm-and-moist Gulf air mass ahead of the front should be sufficient to fuel scattered afternoon and evening showers and storms.  We’re going with a 50% to 60% rain chance during the latter half of Friday.
Once again, “Live After Five” fans and Friday-night high-school football followers should be prepared.
The forecast for Saturday stays very wet as well, although the weather picture for Saturday evening remains a little “cloudy” (pun intended).  With the cool front expected to be draped over our viewing area through the better part of the day, we can expect more rain through the day ... but possibly not an all-day washout.
Most importantly for many of you, the prognosis for Saturday night in Death Valley is not quite as gloomy as it was yesterday.  Entirely rain-free in Tiger Stadium for the LSU-Auburn clash?  Maybe not ... but probably not a stormy night either.
The cool front is expected to slow, possibly even stall, over the southern parishes or the coastal waters into Sunday, keeping the weather a bit unsettled for our coastal communities.  But for most WAFB neighborhoods we expect the rains come to an end late Saturday or early Sunday, with clearing kicking-in by mid-day Sunday, if not sooner.  The weather remains settled through at least the middle of next week.
Keep this in mind: the outlook from the NWS Weather Prediction Center still calls for 2” to 4” of rain between now and Sunday.  While most of us can use the rain, that’s enough to produce some “nuisance” flooding in the usual places.  However, area rivers are in “low flow” (base flow) stages and most should be capable of handling the excess runoff.
In the tropics ... Invest 95L -- the disturbance over the Bay of Campeche -- has not looked good at all today.  What seemed to be headed towards an upgrade to a tropical depression yesterday remains disorganized: so much so that the Hurricane Hunter scheduled to visit the system today was canceled.  While 95L does appear to have a broad cyclonic spin and there is convection (thunderstorms) popping to its south, northerly shear and a slot of dry air to its north and west are keeping the system from developing.
The shear and dry air may fade away some over the next 12-24 hours allowing time on Friday and into the weekend for a depression to form.  But for now, at least, most models either leave a weak system -- probably a depression at best -- in the western Gulf for the next few days or stretch it out across the open Gulf as the upper-level trough and associated front (that will be impacting us on Friday and Saturday) tug at the system.
In either case, we do not anticipate a tropical threat for Louisiana from this system

Wednesday, September 18, 2013

Turning Soggy into the Weekend

By Jay Grymes & Steve Caparotta

We saw a few more showers running east-to-west across the viewing area this afternoon as compared to past days.  We expect even more clouds on Thursday afternoon and we’ll post rain chances in the 30% range for Thursday PM.
Rain chances take a big jump up for Friday and Saturday, with showers and t-storms “likely” for both days as a cool front advancing from the northwest takes advantage of an abundance of Gulf moisture.  We’ll back the rain chances down for Sunday, especially by the afternoon, but by then our attention may be on a potential tropical system in the Gulf.

As you can imagine, a wet forecast could mean the third Friday in a row where Mother Nature plays havoc with high school football and downtown’s “Live After Five.”  And after dodging rain and lightning near the scheduled kick-offs over the past couple of Saturdays in Tiger Stadium, we could be looking at rains extending through much of the Tigers’ SEC opener -- trouble for tailgaters and for fans-in-the-stands.
Admittedly, we can certainly use the rain.  In fact, you probably already know that most of the northern half of the state is under a burn ban and almost all of northern and western Louisiana is posted as “in drought” according to the weekly U.S. Drought Monitor.  None of the WAFB viewing area is currently included in the state’s drought areas but experts have our western communities rated as “abnormally dry” and on the verge of drought for this time of year.
The set-up through the coming days could make for a very wet spell -- the NWS Weather Prediction Center (WPC) is calling for 2” to more than 3” of rain for much of our viewing area between now and Saturday night.  That would not only take a big bite out of the local dry spell, but could lead to some local “nuisance” street flooding and standing water in the “usual suspect” spots over the weekend.  However, most of our local rivers and bayous are running at or near “base flow” (their lowest flow rates) so they have plenty of capacity for rain-generated runoff.  Therefore, we don’t anticipate river flooding at this time.
Then there’s the potential development in the SW Gulf.
Invest 95L -- the disturbance over the Yucatan and headed towards the Bay of Campeche -- appears on a slow path of becoming a tropical depression and could even become T.S. JERRY in the next couple of days.  As a depression, at least, it will be the 5th tropical cyclone to develop in the western/SW Gulf this season.  The four prior systems are: T.S. BARRY, T.S. FERNAND, ‘Cat 1’ INGRID and T.D. #8.  (You’ve got to believe that residents along the Mexico Gulf Coast are ‘storm weary.’)

As you may recall, INGRID’s track was reasonably-well forecasted and ‘she’ never prompted any serious concerns for the central Gulf Coast as her track into Mexico was never really in much doubt.  Unfortunately, the future of 95L is far from clear.
The latest forecasts (‘spaghetti plots’ and intensity forecasts) suggest that a slowly-developing system remains over the western Gulf into the weekend, maintaining a slow motion towards the NW.  But after about 2 to 3 days or so, the models diverge greatly in their solutions.

When models show good agreement through a 3-to-5 day window it suggests that they are all picking up on the same atmospheric steering -- both in terms of direction and speed.  Obviously, such good agreement in multiple models out 3 to 5 days provides confidence.  In this instance, however, we are seeing differences between the models as to what will become the main atmospheric “chauffeur” for the future of 95L into and after the weekend.  In addition, the models are not even in much agreement about potential intensification.
An upper-level trough over the eastern U.S. will send a cool front into the lower Mississippi Valley this weekend, with that front expected to stall along or near the northern Gulf Coast.  Our local rainy outlook for Friday, Saturday and possibly early Sunday will be a product of this front.
That same upper-trough’s impact on steering for the weekend’s Gulf system is the main question at this stage -- and you can find just about any possible outcome depending upon which model you choose.
A couple of models are suggesting that the trough essentially misses the tropical cyclone (whether a depression or tropical storm) -- fails to influence its trajectory -- leaving it to meander in the western Gulf.  That scenario likely favors another landfall for Mexico, this time possibly closer to the TX/MX border.  Other models are showing the trough grabbing the system and bringing it north or northeast, potentially interacting with the stalled front and threatening the U.S. Gulf Coast anywhere from Louisiana to Florida.
Then there is a more intriguing solution that suggest the trough “grabs” most of the system but leaves some of its energy behind, effectively stretching the tropical system across the Gulf and making a big mess of things.  While this could make for a string of very wet days into next week for several Gulf states, the potentially good news here would be that the system would have a very difficult time ramping-up into a destructive tropical wind-and-surge generating storm.
Those of you that have been “storm watching” for a while know that there are some computer models that experts tend to lean towards and others that they tend to discount.  But at this stage -- without a true cyclone yet -- even the more trustworthy models can bounce around in their projections from one computer run to the next.  The point: a ton of uncertainty remains. 
We’re going to have to just sit and wait a while on this one until the steering currents become a bit more apparent.

Tuesday, September 17, 2013

Gradually Increasing Rain Chances

By Jay Grymes & Steve Caparotta

Hot and mainly-dry was the forecast for today, and that’s what most of us got. Yes there were a few showers and flashes of lightning mainly south of metro BR, but for most of us the weather story today was the heat, with highs in the low to mid 90°s.

With daytime temps in the 90°s, low-level Gulf moisture in place, plus a weak quasi-stationary front over the Gulf Coast states, why not more widespread rain today? Because, like yesterday, a mid/upper-level ridge centered near the TX/LA border kept a fairly solid lid on the atmosphere, allowing only spotty showers, at best, to develop during the afternoon.

The weak front currently over our area will dissolve over the next 24 hours. More importantly, the upper-air ridge will slowly weaken and shift to the southeast over the next few days, taking the atmosphere’s cap with it. By week’s end, the current Gulf Coast ridge will have been replaced by an upper-level trough and a surface front. All this adds up to a slow-but-steady rise in rain chances through the work week, culminating in a “rain likely” forecast with our next cold front on Saturday.

Most of us need the rain, but many of us may be disappointed with the Saturday outlook. The current NWS Weather Prediction Center (WPC) forecast has a cold front entering NW Louisiana early Saturday but then only slowly moving southward. The WPC forecast charts keep the front over Louisiana through Sunday into early Monday before finally pushing out to the Gulf.

That scenario looks rather wet for Saturday afternoon, when LSU takes on Auburn in Death Valley, and suggests decent rain chances continuing into Sunday, at least. So, “It never rains in Tiger Stadium.” -- looks like we’ll put that legend to the test.

But then, as we noted, we can use the rain. In addition, we should get a run of days where highs fail to reach the 90°s.

In the tropics ... interaction with the mountains of central Mexico finished-off INGRID’s central core and the National Hurricane Center (NHC) posted the final advisory for ‘her’ this morning at 4AM. Still, INGRID’s remnants continue to dump heavy rains over portions of east-central Mexico, where life-threatening flooding continues.

Even with the strong shear pushing the main convection well east and northeast of the low-level center, the NHC still considers HUMBERTO to be a minimal tropical storm as of 4PM. And the NHC is still holding to their expectations for some modest strengthening over the next couple of days although the outlook no longer calls for a return to hurricane intensity. Regardless, HUMBERTO is expected to lose ‘his’ tropical character by the end of the week and is no threat to any land areas.

The mess in the western Caribbean and extending into Belize and the Yucatan appears to be getting its act together. Late last night we showed a surge in convection just off the coast of Belize -- while there is no clear low-level core, computer models are coming together on the future of this broad low, taking it across the Yucatan and into the Bay of Campeche by late tonight or tomorrow.

As we’ve seen with this season’s BARRY, FERNAND and INGRID, conditions in the SW Gulf have been favorable for slow, limited development.

Guidance is suggesting that this low could become JERRY in the next few days, and unlike the last few systems in this part of the Gulf, it may not continue westward into Mexico. A stalling system later this week could feel a tug to the north or northeast from the anticipated trough over the eastern U.S. into the weekend.

Monday, September 16, 2013

Hot, Mainly Dry Again on Tuesday

By Jay Grymes & Steve Caparotta

As we expected, it was a hot-and-mainly-dry weekend for most of us and the mainly-dry weather -- accompanied by highs in the 90°s -- remains in place into the middle of the week.

Yes, a handful of locations, mostly well south of metro BR, saw a passing shower this afternoon, but they were the lucky ones. 
Tuesday will be another hot day under mostly sunny skies.  The same ridge of high pressure that drove INGRID into Mexico remains parked overhead, putting a substantial lid on the atmosphere.  A pop-up shower or two can’t entirely be ruled out for Tuesday afternoon, but those will be very, very few and far between. We’ll go with isolated afternoon rains, at best, for Wednesday, then increase rain chances to “scattered” for Thursday and Friday.
A cool front is currently draped east-to-west across the mid-Mississippi Valley.  Guidance suggests that the front will try to “backdoor” its way into the viewing area (approach from the northeast) on Wednesday.  However, the boundary is expected to slowly dissipate as at dips south and that means that it will do little to lower our afternoon temps or decrease humidity as it fizzles out.

Daytime heating and continued summer-like humidity will mean scattered afternoon showers and t-storms for Thursday and Friday.
Some much-needed rain appears “likely” for Saturday - - at least for the time being, it looks like another front will make its way through the Bayou State from the northwest on Saturday.  It should reach the WAFB viewing area during the latter half of Saturday then slow to a crawl near the coast on Sunday into Monday.  Clouds and rain should also keep highs in the 80°s for Saturday and Sunday.

In the tropics . . . as you may recall, INGRID became the second hurricane of the season -- and the first in the Gulf -- on Saturday, but was never any threat to the U.S. coast.  INGRID made landfall earlier today along Mexico’s Gulf Coast and has dropped to depression strength this afternoon, but even ‘her’ remnants continue to deliver flooding rains.  In addition, INGRID joins the remnants of the East Pacific’s MANUEL to produce double-trouble flooding for portions of central Mexico.

In the central Atlantic, HUMBERTO lost ‘his’ tropical characteristics on Saturday, but as anticipated by National Hurricane Center forecasters, HUMBERTO made a comeback today, returning to tropical-storm strength as of 10AM. The latest NHC 5-day forecast even calls for HUMBERTO to regain hurricane strength in a few days.  Regardless of what may develop, the system will continue to move towards the north and northeast, posing no threats to land.

Elsewhere, a disturbance over the northwestern Caribbean appears to be headed towards the southwestern Gulf, where conditions are likely to be favorable for some slow development down the road.  For now, the NHC has only a 20% chance for tropical-cyclone formation over the Gulf later in the week, but given its location and the time of year, we’ll keep tabs on it.

Saturday, September 14, 2013

May Have to Dodge Showers Today

A very slow moving cold front will take its time working south. South Louisiana should stay dry through the rest of the morning today, but by afternoon sct’d showers and t-storms will quickly develop. Majority of the activity will develop south of the cold front. So the big question is where the front will be during the afternoon hours. Unfortunately it looks like the front will be just north of Baton Rouge this afternoon meaning pack the wet weather gear for both local college football tailgates. 
The front will continue to sag south this evening finally allowing drier air to work into the capital city. That should result in dry weather for both games. Isolated wet weather will continue south of Baton Rouge into the early evening hours.

Sunday, Monday, and Tuesday will be mainly dry days. The front will stall along the coast allowing for high pressure and drier air to work into South Louisiana. Sunday and Monday expect only a spotty PM t-shower. Highs will be in the low to mid 90°s. Tuesday slightly higher rain coverage will enter the isolated category. Highs will be in the low 90°s.

Friday, September 13, 2013

A Few Showers Overnight

By Jay Grymes & Steve Caparotta

We’re watching pockets of showers and isolated t-storms slide from north-to-south over portions of the Florida Parishes and SW Mississippi, so we can’t say “no rain” for this evening’s ‘Live After 5’ nor for some area high-school football.  But so far, most of the lightning has remained north of the LA/MS state line, so it looks like it will be a fairly quiet evening for most of us.
A weak cool front will pass through the viewing area overnight.  The front will be draped close to the I-10/12 corridor around midnight and is expected to reach the coastal parishes by Saturday’s sunrise.  With the front passing by, we’ll toss in a 20% (to maybe 30%) rain chance into the overnight forecast.  While we can’t rule out some rumbles of thunder, there’s no concern for severe weather.  And if you need some rain, this won’t really be of much help -- don’t expect much in the way of accumulations even if you get a rain tonight.
With the front to our south on Saturday morning, many of us can expect Saturday morning lows in the upper 60°s to around 70° with fair to partly cloudy skies for the Red Stick. 
The front stalls and lingers along or near the coast through the weekend.  Don’t be surprised by a shower or two during Saturday afternoon, but again we put rain chances at a modest 20% (or less) for the day and into early Saturday evening.  Tailgaters may want to keep a watch on the skies, but anything that does develop during the afternoon is expected to be short-lived.
And for the two big college contests in town -- kick-offs for Southern and LSU are both at 6PM -- we may see a shower or two early but we expect mainly-dry weather through most or all of both games.

Even with Baton Rouge on the north side of the front, highs will still get into the 90° to 92° range for Saturday and Sunday.  However, dew points should slip into the mid to upper 60°s for the weekend, so the front will deliver at least a little relief from our traditional summer humidity.  Notice we say “a little relief” -- there is not going to be a big change occurring with tonight’s frontal passage and by early next week our dewpoints will be back to “summer like” numbers.
Sunday looks to be a mostly-dry day and we’ll post rain chances at about 20% or so for Monday.  After that, we’ll “up” those percentages to 30% to 40% or so for Tuesday through Friday.  By mid-week, highs may top out in the upper 80°s: far from cool, but at least not the 90°s!
To our south, T.D. #10 was ‘upgraded’ to T.S. INGRID at 10AM this morning.  INGRID has continued to drift westward over the Bay of Campeche, but the National Hurricane Center (NHC) is calling for a slow motion towards the NNW later today and into early Saturday.  The NHC then forecasts a turn to the NW late Saturday, taking a moderately strong tropical storm into Mexico late Sunday or early Monday.  Computer guidance is on-board with this scenario, so it looks like we can dismiss any lingering concerns about a strengthening INGRID meandering in the SW Gulf into next week.
GABRIELLE weakened to tropical-depression strength earlier today and has continued to degenerate through the today, with the NHC issuing ‘her’ last advisory at 4PM.  The remnant low will continue to accelerate to the NNE and is expected to merge with a cold front on the way into Atlantic Canada.
And lastly ... HUMBERTO was downgraded to a tropical storm at 10AM, with the weakening largely the result of southwesterly wind shear.  The NHC forecast calls for additional weakening in the short term due to continued, possibly increased, wind shear and cooler sea-surface temperatures along HUMBERTO’s forecast track.  Yet somewhat surprisingly, the NHC’s extended forecast currently calls for HUMBERTO to return to hurricane intensity by day 5 as the storm turns to the north, taking the system away from the strong shear and moving towards slightly warmer waters.  We’ll watch to see if this actually pans out, but regardless, HUMBERTO will be no threat to land. 

Wednesday, September 11, 2013

Staying Hot, Slim Rain Chances

By Jay Grymes & Steve Caparotta

There were a couple of blips on Titan9 Doppler this afternoon including showers that passed over Denham Springs and downtown Baton Rouge.  But for most of us, it was just hot and dry ... and that’s just what we expect for Thursday and Friday.  Yes, a pop-up afternoon shower or two are still possible over the next couple of days -- that’s the nature of even “dry” summer days along the Gulf Coast.  But any showers that do develop through Friday will be spotty at best and probably very short-lived.  Besides, if you are lucky enough to get one of them, your yard will be thankful.
Although it will be quite warm, all looks good for Friday’s “Live After 5” in downtown BR.

Our forecast remains essentially unchanged for the next two days: morning lows near 70° to the low 70°s for most of the BR metro area with afternoon highs generally in the low 90°s with some WAFB  neighborhoods flirting with the mid 90°s.  Rain chances will be next to nil for Thursday and Friday.
We’re keeping rain chances for Saturday at under 20%, so LSU Tiger and Jaguar Nation tailgating should be okay for the most part -- just be ready for a quick sprinkle through the course of the afternoon.  We’ll go with 20% rain chances for Sunday afternoon.
The upper-level ridge that has dominated much of the eastern half of the U.S. over the past couple of days will retreat to the west over the next two days.  At the same time, a trough will dig southward over the eastern U.S. and try to push a front to the Gulf by Saturday.
For now, we think a weak cool front will make its way into the viewing area on Saturday.  It will only mean a slight increase in rain chances for Saturday afternoon and won’t deliver a  significant cool-down, although it may drop afternoon readings a couple of degrees around the area.  The lingering remnants of the front could help with low-end rain chances for Sunday too.

In the extended outlook, there is promise of a somewhat stronger cool front -- essentially a “backdoor” front -- arriving late Monday or Tuesday.  It’s a little too early to say, but that front currently offers a better chance for some needed rains by Monday, Tuesday and into Wednesday.
In the tropics, we’re focused on three features -- ‘Cat 1’ HUMBERTO in the eastern Atlantic, T.S. Gabrielle in the western Atlantic, and “Invest 93L” in the western Caribbean. 
HUMBERTO was officially upgraded to hurricane status at 4AM (CDT) this morning, the first hurricane of the 2013 season and just three hours shy of tying the record for the “latest-forming first hurricane” since the satellite-era of tropical cyclone tracking.  The National Hurricane Center (NHC) expects HUMBERTO to continue on a north-to-NNW course for the next couple of days, then turn to the west over the weekend. HUMBERTO is forecast to reach ‘his’ peak intensity later today or tonight, with the system dropping to tropical-storm strength by the weekend.

GABRIELLE has been weakening while drifting slowly to the west and NW for much of the day.  The system is barely maintaining ‘her’ tropical-storm structure due to shear, with much of the convection to the east of the defined low-level circulation.  It has been slowly moving away from Bermuda and is expected to begin accelerating to the NW, then north, and finally to the NNE in the coming days, eventually transitioning to a post-tropical (extra-tropical) system.  Those in the Canadian Maritimes and Newfoundland should monitor GABRIELLE into the weekend. 
And for Gulf interests, models suggest that “93L” could quite possibly become INGRID once the disturbance makes it across the Yucatan and enters the Bay of Campeche.  The next question will deal with its “residence time” over those warm waters.  While some of the computer forecasts take the system (T.S. INGRID) directly into Mexico, several other models are hinting at the system stalling over the Bay and lingering there -- possibly through the weekend.

While we do not anticipate a strengthening INGRID becoming a threat for the central Gulf Coast, the longer the system remains over water the more uncertain we are about ‘her’ final destination.  Stay tuned ...