FXUS64 KBRO 051954
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
254 PM CDT Thu Aug 5 2021

.SHORT TERM (Now through Friday Night): The leftover outflow 
boundaries and afternoon heating have fired up some more conv across 
mainly the northern Ranchland counties with Kenedy County currently 
seeing the strongest conv. This conv will persist into the afternoon 
and early evening hours and then should diminish steadily with the 
loss of the afternoon heating. The 500 mb ridging that is trying to 
nose into the region from the east will be competing with the 
southern end of a 500 mb trough digging over the lower Miss River 
Valley. The influence of the trough axis will combine with the sea 
breeze/diurnal effects to force the conv to linger on into Fri. So 
will maintain some mention of conv pops into Fri. 

The short term model sets have started backing of on the pops for 
Fri with the exception of the NAM which is the most aggressive for 
tomorrow. 

Will go pretty close to a model blend for temps/pops through Fri 
Night. 

.LONG TERM (Saturday through Thursday): Subtropical ridging at
500mb will be the dominant feature across our area this weekend
and early next week. The resulting subsidence will effectively
limit moisture at lower and middle levels, maintaining mostly
rain-free conditions and hot daytime temperatures. On Tuesday and
Wednesday, the ridge and eventual closed 500mb high will move
inland and become centered over southern Texas, prolonging the
general theme of subsidence across the Rio Grande Valley. Overall,
the midlevel pattern will remain largely unchanged through
Thursday. Any stronger midlevel troughs or closed lows should pass
well to our north, effectively keeping any features from breaking
down or even weakening the subtropical ridge. Heat index values
will routinely fall into the 105-110 degree range across much of
the CWA through the middle of next week. The usual hot spots in
Starr and Zapata Counties will need to be monitored for potential
Heat Advisory conditions this weekend and early next week.

&&

.MARINE (Now through Friday Night): A relatively weak PGF will 
continue over the lower TX Bay and Gulf waters through tomorrow night
as elongated surface ridging prevails over the Gulf of Mex. This 
will maintain light to moderate onshore winds and low swells 
across the region with no SCA conditions expected through Fri 
night.

Saturday through Tuesday: Broad high pressure across the Gulf of 
Mexico will favor moderate southeasterly winds and gradually 
building seas to start the weekend. Low pressure developing over 
the Southern and Central High Plains will tighten the surface 
pressure gradient late Saturday into Sunday, favoring southeast 
winds of 15-20kts through Monday afternoon. Small Craft will need 
to Exercise Caution during this time. Wave heights will remain 
slightly elevated through Monday evening as a result. The pressure
gradient then weakens on Tuesday allowing both winds and seas to 
relax.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  78  93  79  94 /  20  10  10   0 
BROWNSVILLE          79  96  80  95 /  20  10  10   0 
HARLINGEN            77  96  78  98 /  20  20  10   0 
MCALLEN              77  96  77  99 /  20  20  10   0 
RIO GRANDE CITY      76  99  77 102 /  40  10  20   0 
SOUTH PADRE ISLAND   82  88  82  90 /  20  10  10   0 

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

This product is also available on the web at:
https://weather.gov/rgv

Short Term/Aviation...60-Speece
Long Term...55-Adams