Evening Update

[Anonymous]

Definitely something to watch but not looking good attm...

IWIC Atlantic Basin Tropical Weather Discussion - 13 June 2004 - 9:00 PM EDT

Reconnaissance aircraft did find a broad low level circulation center. But as suspected, the system wasn't very organized and winds were relatively light. The system wasn't strong enough and it is our opinion that the Tropical Prediction Center did a good job by not upgrading the low to tropical depression status.

One cycle that we've seen each day is a flare-up of convection during the morning hours and then quick dissipation during the evening. Convection is once again dissipating and to put it simply, the broad low looks rather pathetic. The shortwave trough that has been progged to reach the northern Gulf of Mexico by Sunday is already beginning to have an influence. Water vapor imagery reveals that most of the moisture in the central Gulf is being pulled northward at a fairly rapid rate of speed as it's being sheared. We did anticipate that the low would have one more oppurtunity to develop tomorrow morning, but that doesn't even look likely at this point. Shear levels should continue to increase during the overnight hours. While convection may flare-up out ahead of the shortwave, it should be rather disorganized. No development is expected.

Even though organization is not expected, the Gulf Coast is still at a fairly high risk of experiencing heavy rainfall. While the tropical models have been all over the place, the global models have been fairly consistent. The GFS, CMC, NOGAPS, and UKMET have all been in relatively fair agreement that a MLC or LLC will reach southern Louisiana within 24 hours. If these model runs verify, that would likely place the heaviest rainfall from southeast Louisiana, through the Florida panhandle. Flood watches have already been issued by the New Orleans National Weather Service Office and more should be expected to go up by tomorrow afternoon. There is a chance that our Gulf feature could race up the shortwave faster than expected, and that would decrease the chances of minor flooding. But it would be safe to plan for 3-8 inches of rain if you're in the areas mentioned.

[HURAKAN]

the Tropical Prediction Center did a good job by not upgrading the low to tropical depression status.

According to you the TPC/NHC did a great job not upgrading this system to a TD, and I ask you, with what data or information would the TPC/NHC do such thing? They wouldn't upgrade a system until it has a fairly good developed low level circulation with copious amounts of convective thunderstorms around or near the low. So, with the low in the gulf not having any of what I mentioned before they wouldn't upgrade this system.

[Anonymous]

Sometimes they can be quick to upgrade systems that are close, but not quite, TD status in the Gulf of Mexico (i.e. Grace last year). Nothing wrong with that if it is clear the storm will further intensify or is real close to land...but with this one it would have been rather pointless because in all likelihood it'll only go downhill from here. Don't take the statement the wrong way though...we both have the uttermost respect for the forecasters at the NHC.

[Anonymous]

0Z tropical model plot FWIW...

[Anonymous]

It isn't at all uncommon for the TPC to classifiy weak systems if they show potential for development if they're racing towards the Gulf Coast. Instead, they waited for more persistence and evidence...it was a good call. I was a bit surprised that they did wait based on what they've done in the past and that is why it was mentioned.

[Anonymous]

Also look at the latest global model 850-200MB shear forecasts...shear is forecasted to increase in the northern Gulf ahead of the shortwave over the next 24 hours...as anticipated.

18Z AVN

12Z CMC

12Z NOGAPS

[MGC]

Perhaps the NHC did not rush to upgrade based on our criticism from past seasons................MGC

[WXBUFFJIM]

I'll admit, if nothing develops tonight you might as well forget tropical development because the chances appear to be decreasing with each hour I'm in this chair.

However very heavy rain is the primary risk with Louisiana, Mississippi, and Alabama right at ground zero.

Jim

[Anonymous]

Perhaps the NHC did not rush to upgrade based on our criticism from past seasons................MGC

[CajunMama]

I know this has been asked and answered before but....which of the models shown in Supercanes' post has the most accuracy?

[Anonymous]

I know this has been asked and answered before but....which of the models shown in Supercanes' post has the most accuracy?

Out of those models, BAMM should be used the most with shallow systems (weak ones). The GFDL is pretty good but it hasn't been able to sustain a cyclone for more than 12 hours. The rest are.....ok.

[CajunMama]

Thanks! I was just wondering since the purple and yellow bars go straight through me! I can't get away from LSU colors....aacckkkkk!