KATC StormTeam 3 Weather BLOG

The NHC just dropped Tropical Storm Warnings for the Gulf Coast as the depression is too close to the coast for significant strengthening and appears to already be working its way inland….

Tropical Storm warnings have been issued from the mouth of the Mississippi including New Orleans and Lake Pontchartrain through the eastern Florida Panhandle.  Officially a tropical depression, #10 showed more organization this afternoon so the “sub” part of the moniker was dropped.  Since this system is so close to land there remains a small window of opportunity for an upgrade to a tropical storm prior to landfall which will either happen later this evening or by early tomorrow morning.  As this system moves westward we will continue to be on the dry side of things but we will get introduced to more of a tropical atmosphere by tomorrow evening into Sunday.  In Acadiana, we still can expect some tropical shower activity moving into the area late tomorrow afternoon into tomorrow evening, with better rain chances possible for Saturday night into Sunday.  To make things more interesting, a tropical disturbance in the NW Caribbean will get drawn northwestward this weekend with the distinct possibility of this disturbance adding to our rain chance by Monday.  There is even the remote possibility that this system could develop so we’ll keep a close eye on it.  The bottom line is that our nice, dry, comfortable weather will be gone after midday tomorrow with high humidity and good rain chances likely through much of next week.  Incidentally, the long range models keep significant fronts away from the area and active disturbances in the Caribbean and possibly the Gulf into the second week of October.  So our tropical season is still several weeks away from ending.  Have a good weekend and enjoy the tropical skies…it should look pretty cool especially late tomorrow.    

As expected we have Subtropical Depression #10.  As of 10am it was located at 29.2N 85.5W or about 45 miles southwest of Apalachacola, Florida.  It is moving toward the NW at 8 mph.  Winds are near 35mph and the pressure is down to 1004mb, or 29.65 inches.  Tropical Storm Warnings have been issued from Apalachacola, Florida to the Mouth of the Mississippi River.  No advisories are currently in effect for Acadiana.  Another update at 1pm.

Recon aircraft are currently investigating the disturbance in the northern Gulf of Mexico.  During the pre-dawn hours infared satellite loops, and local radars from the Florida panhandle are certainly showing a bit more organization today than yesterday.  In fact most of the offshore buoys in the area were recording pressures down to 1005 mb, and some windspeeds were up to 30 kts.  Also the positioning of the buoys were showing SE winds east of the center and NW winds to the west indicating that a closed low has formed.  Yesterday the recon mission also found a closed low about 120 miles west of Tampa, but since there wasn’t significant thunderstorm activity or strong winds near that center, the NHC decided to hold off on upgrading this disturbance, as well as issuing any advisories.

Later this morning after all of the recon data is in, I wouldn’t be surprised to see at the minimum “Sub-Tropical” Depression #10, and advisories would be issued along the northern Gulf coast.  Whether its Sub or Tropical Depression, I would expect Tropical Storm Warnings to be issued from the Florida Panhandle westward to at least the mouth of the Mississippi River, maybe as far west as Grand Isle.  Coastal Flood Watches have already been issued for the SE Louisiana coastline from Morgan City eastward to Destin, FL. 

If we don’t get an advisory on this by 10am Friday.  I would expect more information to roll in this afternoon, and advisories might be put in by 4pm.  I will have an update either way when we get the word from the NHC.

Hurricane Hunters investigated the area of disturbed weather off the west coast of Florida today, and while they found a low level circulation and pressures low enough to be a tropical or sub-tropical storm, the lack of convection and strong enough winds near the center have kept the NHC from upgrading this system.  More than likely there will be slow development with this feature through the next 24 hours and I would expect tropical or sub-tropical storm status for this system by tomorrow night.  The Hurricane Hunters found a defined low level circulation about 115 miles west-southwest of Tampa so we’ll see if convection can get organized around this area over the next 24-36 hours, in the warmest part of the Gulf as Dave alluded to in the previous entry.  Since there hasn’t been any evidence of rapid organization today, it looks like a hurricane is not in the mix, but a respectable tropical storm will be a distinct possibility.  The computer models continue to have a hard time resolving what is going to happen but I would expect tropical storm conditions possible for the western most Florida Panhandle, coastal Alabama and Mississippi, with the possible landfall over eastern or southeastern Louisiana on Saturday.  Thereafter, the remnants of this system will give us the chance of squally showers late Saturday and a good chance of tropical shower and squalls Saturday night into Sunday, with lingering tropical moisture and rains possible through Monday.  Another weak front will approach the middle part of next week.  In the near-term expect another gorgeous evening tonight and a sunny and warm one tomorrow.   

So far not much has changed in the disturbance over the state of Florida.  A big upper level low has now moved west of the state.  We were able to see a small surface circulation move onshore near Cape Canaveral yesterday afternoon, and whats left of that circulation is now near Orlando in Central Florida.  There was a bit of a low level circulation evident over extreme Southwest Florida near Naples late yesterday, and that is showing up on radar now about 50 miles offshore in the Gulf of Mexico.  At this time it is uncertain just which surface low will be the “one”.    If the low near Orlando moves offshore it will be running into a lot of wind shear.  It will then track WNW over the northern Gulf waters.  Most indications are for some slow development maybe Tropical Depression or possibly a weak tropical storm.  The tracks generally take this toward either New Orleans, or along the Mississippi/Alabama Gulf coast.  If the “Naples” low forms we might have a stronger tropical system because it will linger over the waters longer.  Also it would encounter less wind shear, and it would move over the “loop current” of very warm waters with high Tropical Cyclone Heat Potential (click to see graphic).  Many tropical systems, even with hostle upper level environments have been known to increase in intensity easier and quicker when passing over those warm waters.  Also the southerly track would track the system farther west in the period possibly impacting Acadiana westward to the upper Texas Coast.

Today has been another day of more questions rather than answers concerning the disturbance in the Eastern Gulf and Florida.  Visible satellite imagery and surface pressure analysis have shown some development along the east-central coast of Florida and just north of the Florida Keys in the Eastern Gulf.  The question for the next 24 hours will be if and what surface system develops and where that surface circulation develops in the Gulf.  Most of the tropical computer models can’t be trusted at this point until a surface circulation can be better defined.  Nonetheless, the deep mean layer flow through the weekend will bring this system to the west to west-northwest.  So I am still expecting some sort of weather with this system here in Acadiana, but obviously we can’t tell you who will get the worst of this system yet.  Tomorrow we should have a better idea.  The bottom line for the near term, expect breezy and comfortable conditions through Friday with breezy conditions this weekend with tropical squalls possible.  This system will probably not be a storm surge concern in Acadiana, but coastal flooding could be possible for Eastern Louisiana.  So as we say…stay tuned to KATC for further developments and be ready for just about anything this weekend.  

Higher humidity and widely scattered showers moved into the area today, but drier more comfortable conditions will return for tomorrow and the rest of the week.  Our attention will continue to be on a disturbance over Florida.  This will likely be a Gulf weather-maker, and more than likely a tropical storm or sub-tropical storm by late Thursday.  While conditions aloft reflect more of a cold core, non-tropical system, there is a strong possibility that this system will gradually transform into a tropical hybrid or even a purely tropical system.  Although we are in the formative stages and no true surface system has been identified, the computer models are pretty much dragging this system across the Northern Gulf with some weather likely to reach Acadiana and the coast by Saturday.  There is still plenty of dry air on the western flank of this disturbance while the upper low to the west (roughly near Tampa) and the proximity of this system to land will keep this from any rapid development over the next 24 hours.  But whatever emerges in the Eastern Gulf Thursday will have roughly 36 hours for strengthening as this system will cross the warmest waters in the Gulf of Mexico.  As we saw with Humberto, there will be the possibility for this system to become a hurricane, but because of the near-term hurdles this system has to cross, a strong tropical storm would be the best bet now…but anything can happen.  In the near-term I would be looking for a surface low to develop off the southern and eastern Florida coast tonight, crossing the peninsula tomorrow, and then emerge in the Gulf by early Thursday.  Conditions across all of coastal Louisiana will likely see winds and seas increasing Friday with tropical storm conditions likely this weekend.  Obviously it is way too early to make a call for landfall, but anywhere across Louisiana through the upper Texas coast would be the odds on favorites today.  So this weekend we will likely see some sort of rain and some sort of wind, so be prepared.

Several things appear to be coming together over the Western Atlantic Ocean between the Bahamas and the East Coast of Florida.  First, the old cold front that continues to bring us pleasant weather is draped over the central part of Florida and extends along the East Coast.  Second an upper level low over Cuba, and third a weak tropical wave over the central Bahamas.  Wind shear values are high over the eastern Gulf, but that is forecast to weaken over the next couple of days.  Computer models are indicating some development by Thursday, but each model is developing a low in a different location.  Some develop it in the Bahamas, some over near the Florida coast around Jacksonville, and still others developing the low near Key West.   The next few model runs should come into more agreement and the forecast will become clearer over time.  What we do know is that no matter what develops, rain will be back in the forecast late this week and into the weekend. 

Our nice weather pattern will continue for several more days as a dry ridge of high pressure stays in control through at least Wednesday.  As we talked about late last week, there may be something brewing in the Gulf of Mexico later this week.  A weak area of low pressure near Daytona Beach remains disorganized and not-tropical in nature.  Computer models are drifting this system westward across the Gulf later this week and into the weekend.  Barring tropical development this system should bring showers and storms back into the area Friday into the weekend.  Some slow development will be possible over the next few days, but at first this may be more of a tropical hybrid, not purely tropical in nature, but a slow transition to a more significant system could be possible by this weekend.  The bottom line, conditions will change for the latter part of the week with at the very least a better chance of storms for the weekend, and perhaps fresh easterly breezes.  All interests in the Gulf of Mexico should be alert for something later this week…stay tuned as this will be the weather-maker we’ll talk about all week long.