104 
fxus64 khgx 040158 
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Area forecast discussion 
National Weather Service Houston/Galveston Texas 
858 PM CDT Thursday Jul 3 2008 


Discussion... 
southeast Texas showers and thunderstorms have come to an end this 
evening. Current forecast for the rest of the night looks good...so 
no update is needed at this time. 42 
&& 


Previous discussion... /issued 728 PM CDT Thursday Jul 3 2008/ 


Aviation... 
line of rain showers/thunderstorms and rain between kcxo and kcll at the 00z hour slowly 
drifting nw'ward. Expect dissipation over next couple of 
hours with setting sun...but kcll may experience some short-lived 
vcsh/isolated ts from this activity. Today's lull (with 10 percent or 
less regional coverage) may be the 'charge' day needed for increased 
convective coverage over the fourth. Deep ll moisture with 
anticipated Gulf moisture surges...decent convergence along a middle 
morning Gulf Breeze...and a primed non-turned over environment 
increase confidence that tomorrow will be at least a scattered thunderstorms in the vicinity day. 
Once convection begins...best to provide updated amendments to the 
specifics of local precipitation/storm behavior. 31 


Previous discussion... /issued 337 PM CDT Thursday Jul 3 2008/ 


Discussion... 
slightly drier air and subsidence effectively keeping the lid on 
convective development this afternoon. Visible satellite imagery shows 
a convective outflow crossing through our SW zones. Could see some 
isolated rain showers/thunderstorms and rain form along this boundary before sunset...so 
kept 20 probability of precipitation in forecast. Airmass will remain uncapped on Friday with 
convective temperatures only in the middle/upper 80s...and the seabreeze 
serving as a focus. Expect isolated to scattered convective 
development...with best coverage south of I-10 where the deepest 
moisture (pws 1.6-1.8 inches) will be in place. However...have 
lowered probability of precipitation for Friday slightly and improved sky cover a bit given 
uncertainty on whether or not The Wedge of more subsident air will 
remain over the area. As is typical with diurnal activity...the 
scattered showers/thunderstorms should dissipate in time for the 
Fourth of July evening festivities. 


The weak upper low over the northwest Gulf is forecast to wash out by 
late Friday. Flow at the 300 mb level becomes more diffluent by 
early next week as general troughing develops over the lower MS 
valley. All of the models show the evolution of an inverted 
trough over south Texas...along with an increase in 850 mb flow off 
the Gulf and a deepening of the moisture. The NAM/European model (ecmwf) are much 
faster with this scenario...with 2+ inch precipitable waters  spreading into the 
area by late Saturday/Sunday. The GFS is much slower...delaying 
the arrival of the deeper moisture until Tuesday. For now have 
stayed on the low side for probability of precipitation (20s/30s) Saturday through Monday. 
However...probability of precipitation may need to be increased this period if models come 
into better agreement. Have made no changes to the forecast beyond 
Monday. Temperatures will remain near normal this period. 


35 


Marine... 
not too many changes with this package as the gradient remains weak 
in between/far away from any significant large scale weather systems. We 
could see a slight increase with winds the next several days as in- 
creasing moisture helps to increase probability of precipitation across the area. 41 


&& 


Preliminary point temps/pops... 
College Station (cll) 71 95 72 95 73 / 10 20 10 20 20 
Houston (iah) 72 93 73 93 73 / 20 30 20 30 20 
Galveston (gls) 78 89 79 90 79 / 30 40 30 30 20 


&& 


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


$$ 


Discussion...42 
aviation/marine...31