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Area forecast discussion 
National Weather Service Brownsville Texas 
805 PM CDT Sat Sep 6 2008 


Discussion... 


East to northeast surface flow continues to 
dominate the weather pattern across deep south Texas. Most of the 
shower and thunderstorm activity has remained well offshore of the 
Lower Texas coastal waters this afternoon and evening. Radar 
trends also indicate more showers and thunderstorms across 
tamaulipas in Mexico. All of this activity has been moving to the 
west southwest. The bro sounding this evening showed a precipitable water of 
2.19. Midlevel flow pattern across Continental U.S. Shows a broad trough over 
the central part of the country. The forecast indicates this 
feature will move eastward and flatten out as it does. 500 mb 
ridge remains located across the Gulf of Mexico back into northern 
Mexico and Baja California California. 


The path of Hurricane Ike still remains uncertain. The National 
Hurricane Center forecast takes the storm through the Turks and 
Caicos Islands tonight and into southeastern Cuba by Sunday 
night. Ike is forecast to emerge back into the open waters of the 
Gulf of Mexico sometime late Tuesday. Thereafter...the NHC tracks 
the storm northwestward into the open waters of the Gulf. At this 
time it is too early to know what path Hurricane Ike will take 
once entering the Gulf of Mexico since there is a large spread in 
the individual model solutions after Ike enters the Gulf. The 12z 
model run from the European model (ecmwf) keeps Ike south of the coast of la and 
deviates from the GFS solution which tracks Ike into la. The European model (ecmwf) 
solution is probably an unlikely scenario and its outcome is 
partially influenced by the formation of a ridge of high pressure 
over northern Mexico that forces Ike to turn southward around the 
eastern side of this ridge. The other models keep this ridge 
farther south. 


We will update you with the latest NHC forecast in the next 
forecast update. 


Across deep south Texas surface high pressure remains to the north 
with a weak area of low pressure over the Bay of Campeche. A 
surface flow from the east to southeast will gradually dominate 
the weather as this weak low pressure system moves northwestward. 
Tropical showers and thunderstorms are forecast to increase and 
possibly begin to affect portions of deep south Texas early 
Sunday. A blend of the GFS and NAM model was used in the grids 
into early next week. Sky grids were also adjusted to reflect the 
changes made to the probability of precipitation. 


&& 


Marine...buoy 42020 reported east-northeast winds around 16 knots 
gusting to around 18 knots with seas of 3 feet with a period of 5 
seconds at 19 CDT/24 UTC. Light to moderate winds and low to 
moderate seas are expected along the Lower Texas coast tonight 
through Tuesday as weak surface low pressure continues to prevail 
over deep south Texas. Seas are forecast to increase around the 
middle of next week...with a Small Craft Advisory possible later 
next week...as swells from Hurricane Ike approach from the east. 
Mariners are urged to monitor the progress of Ike through the next 
several days. 


&& 


Aviation...light winds with mostly clear skies tonight will give 
way to moderate winds with partly cloudy skies and thunderstorms in 
the vicinity tomorrow. 


&& 




Previous discussion... /issued 145 PM CDT Sat Sep 6 2008/ 


Discussion...isolated streamer showers could influence deep south 
Texas for the next few days. Temperatures will be near normal for 
this time of year under partly cloudy skies. A high pressure ridge 
builds over south Texas at the surface with a weak trough at 500 mb. 
The bro sounding this morning showed a precipitation water 2.19 and a 
k-index of 35. Long term models might indicate an increase in 
showers or thunderstorms by the middle of next week. 


&& 


Preliminary point temps/pops... 
Bayview/Port Isabel 77 91 79 91 / 20 30 10 10 
Brownsville 75 92 77 93 / 20 30 10 10 
Harlingen 74 93 76 94 / 20 30 10 10 
McAllen 75 95 77 95 / 20 40 10 10 
Rio Grande City 75 97 76 97 / 20 30 10 10 
South Padre Island 79 90 80 90 / 20 30 10 10 


&& 


Bro watches/warnings/advisories... 
Texas...none. 
GM...none. 


&& 


$$ 


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