600 
fxus64 khgx 250044 
afdhgx 


Area forecast discussion 
National Weather Service Houston/Galveston Texas 
744 PM CDT Thursday Jul 24 2008 


Aviation... 
bit of a speed convergence zone located just inland of the 
coastline has help generate showers and thunderstorms late this 
afternoon. Expect the winds along the immediate coast to diminish 
and allow the convergence zone to dissipate. Reflected this 
thinking in the terminal forecasts with lessening rain chances by 
03z over the metropolitan Houston sites and diminishing wind speeds at 
lbx and gls between 02z and 03z. 


Because of the rainfall pattern today and the building high 
pressure ridge overhead...MVFR conditions due to light fog and 
ceilings will be possible overnight tonight. The MOS guidance did 
not pick up on this as much as did the nam12 time sections for 
some of the sites. As the confidence level is moderate at best... 
will see how the observed trends go for the 06z forecast package. 


For the second 12 hour period...expect VFR conditions to develop 
by 14z. From hou to the coast the models indicated isolated to 
scattered showers were possible in the morning and thunderstorms 
in the afternoon. 


40 


&& 


Previous discussion... /issued 246 PM CDT Thursday Jul 24 2008/ 


Discussion... 
moisture level will start to lower Friday as the upper high center 
shifts southeast to Texas and Oklahoma. Upper high pressure 
ridging and westerly flow at the lower levels will result in 
daytime temperatures climbing to above seasonal normal values 
during the weekend. Precipitable water values from about 2.3 inches today over our 
County warning forecast area will lower to about 1.7 inches during the weekend as per GFS. 
Middle and upper level subsidence will prevail the weekend and into 
early next week. Maximum temperatures during the weekend and Monday should 
climb to the upper 90s inland areas. Middle afternoon heat index 
values will be just below local criteria for excessive heat 
advisory. This will have to be closely monitored. The upper high 
will retreat slightly by the middle of next week resulting in the 
upper trough getting close to our region just to the east. Precipitable water 
values will gradually climb during this period. We shall introduce 
probability of precipitation for the last few days of our forecast package reflecting the 
anticipated change. 


Marine... 
gradient relaxing and seas dropping will continue the Small Craft Advisory for the 
offshore waters 6z. Seas should drop below 6 feet by then. Fairly 
light S winds becoming SW at times through the weekend. Seas 
dropping off to below 4 feet. 
45 


&& 


Preliminary point temps/pops... 
College Station (cll) 75 96 75 98 75 / 40 20 10 10 10 
Houston (iah) 75 93 75 96 75 / 40 20 10 10 10 
Galveston (gls) 80 89 80 89 80 / 40 20 10 10 10 


&& 


Hgx watches/warnings/advisories... 
Texas...none. 
GM...Small Craft Advisory until 2 am CDT Friday for the following 
zones: waters from Freeport to the Matagorda Ship Channel 
20 nm to 60 nm...waters from High Island to Freeport 20 to 
60 nm. 


&& 


$$ 


Discussion...43 
aviation/marine...40