059 
fxus64 klix 220929 
afdlix 


Area forecast discussion 
National Weather Service New Orleans la 
429 am CDT Thursday may 22 2008 


Short term... 
the tale of two troughs continue to keep the country in their 
grip. With an upper trough on either side of the country...it is 
obvious that between the two...there will be an upper ridge. This 
ridge will continue to amplify well into Canada over the next few 
days. Normally a Continental ridge would lead to some unwanted 
roasting from the Gulf south well into the northern Canadian 
plains. Can't speak for the northern teir of states but we will be 
quite fortunate down here. A deep maritime ridge that developed 
over the Carribean has moved into the Gulf and will spread across 
the area today. This will bring a deep moisture column which will 
easily help get ts started. The cooling sh/ts will keep temperatures from 
getting out of hand. The deep moisture will also help water born 
mesoscale boundaries develop and move well away from their source. 
These boundaries are better known as sea breezes and lake breezes. 
We may see this start to set up today but Friday looks to be a prime 
opportunity for these boundaries to meet over the New Orleans 
metropolitan area. 


The mesoscale convective system feature over the northern Gulf will continue northward 
this morning and eventually turn more easterly with the mean flow. 
This area is being generated with middle and upper dynamic forcing. 
Ts that form today through the weekend will be mainly forced by 
heating and mesoscale boundaries. 


Btr and mcb will have a slightly more volatile atmosphere today if 
they can get some strong heating. The heating will cause lapse 
rates to decrease and adding moisture to the primed atmosphere 
will only help bring about an isolated severe today in the form of 
straight line winds and hail. Things change a bit Friday as the upper 
ridge sets in aloft warming 500mb temperatures to -6 instead of todays 
-10. Hail will be a decreased threat tomorrow but what is going 
to be a possible problem tomorrow will be wet downbursts as ts 
will become water loaded with precipitable water values reaching over 2". 




Long term... 
no changes at this time to extended. 


&& 


Aviation... 
ceilings should be above 10k' for the most part with some sct015 
clouds around. Ts will begin to break out across most of the area 
today and wind shear near these storms will be quite strong. 
Expect an increase in areal percentage of ts development tomorrow 
starting during middle to late morning. Some sea breeze collisions around 
the msy metropolitan area should bring about a fairly strong heavy ts at 
or near the terminal. 


&& 


Marine... 
exercise cation due to onshore flow of 15 knots but no other 
flags. Strong to severe ts will progress through the outer waters 
today and mariners should monitor weather radios for any warnings 
that become necessary. 


&& 


Preliminary point temps/pops... 
mcb 87 68 89 72 / 40 30 50 20 
btr 88 70 90 73 / 50 30 50 20 
msy 86 73 88 75 / 60 30 60 30 
gpt 85 70 86 74 / 40 30 50 30 


&& 


Lix watches/warnings/advisories... 
la...none. 
GM...none. 
MS...none. 
GM...none. 
&& 


$$