Weather

902 
fxus64 khgx 072029 cca 
afdhgx 


Area forecast discussion 
National Weather Service Houston/Galveston Texas 
330 PM CDT Thursday Aug 7 2008 


Discussion... 
increased subsidence resulting in much less convective coverage 
today compared with Wednesday. A few isolated -shra/-tsra have 
managed to develop along the seabreeze over Galveston County. This 
activity will dissipate by sunset. 


Little change in the upper air pattern is forecast through early 
next week with a flat upper ridge persisting over most of Texas 
and the southwestern states while troughing remains in place over the 
eastern states. A backdoor front is forecast to stall over 
Louisiana Friday/Saturday with an axis of deeper moisture (2 inch 
pws) pooling to the west of this boundary. A series of upper level 
disturbances in the northwest flow aloft will result in convective 
development along the stalled boundary each afternoon. Models 
differ on the position of the moisture axis...with GFS keeping it 
east of the area...while the NAM/European model (ecmwf) runs show at least our 
eastern zones affected. Have 30 probability of precipitation going for our far eastern zones 
Friday/Saturday aftns...and for the NE zones Sunday where capping 
should be weakest and moisture deepest. An inverted-v profile is 
present in the forecast model soundings arguing for the potential 
for one or two pulse-type severe storms over the eastern zones each afternoon 
Friday through Sunday. Downburst winds would be the main threat. 
Elsewhere...subsidence will keep the lid on convective development 
through early next week except along the seabreeze. Will have 20 
probability of precipitation for the seabreeze...10s elsewhere. Latest runs of the GFS/European model (ecmwf) 
forecast an amplification of the pattern toward the middle of next 
week...with the possibility of a weak front pushing into the County Warning Area 
Tuesday/Wednesday. For now...have just added 20 probability of precipitation to the forecast 
area wide this period. Temperatures will be typical for August through the 
period. Stayed a couple of degrees above MOS for maximum temperatures through 
the period as MOS has been running too cool this Summer. 


35 


&& 


Aviation... 
isolated to scattered showers and thunderstorms near and along the 
sea breeze boundary moving slowly north from the coastal to adjacent 
counties middle to late afternoon. We did include thunderstorms in the vicinity for affected taf 
sites this afternoon. Expect essentially same overnight conditions 
as previous night but somewhat less low cloud cover developing 
after midnight. Mainly light fog developing toward morning for lbx 
and to a greater extent cxo. 37 


&& 


Marine... 
higher pressure over the Gulf and lower pressure over the Southern 
Plains will be the prevailing weather pattern. Typical Summer 
diurnal cycle expected through the forecast period the strongest 
winds (10-15 kts) coastal waters and mouth of bays at night. 
Southerly winds becoming more southwest late night hours. Tide 
levels remaining near normal. 37 


&& 


Preliminary point temps/pops... 
College Station (cll) 75 98 75 98 76 / 10 10 10 10 10 
Houston (iah) 75 97 75 97 76 / 10 20 10 20 10 
Galveston (gls) 81 92 81 92 82 / 10 10 10 10 10 


&& 


Hgx watches/warnings/advisories... 
Texas...none. 
GM...none. 
&& 


$$ 


Discussion...35 
aviation/marine...37