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Area Forecast Discussion (AFD)

Issued by Brownsville/Rio Grande Valley, TX (BRO)

                            
000
FXUS64 KBRO 250009 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
708 PM CDT Sun Mar 24 2019

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...Steady southeast flow will continue to allow abundant
low level moisture to increase across the CWA. Winds will relax 
somewhat through the evening hours with MVFR to eventually IFR 
conditions by early monday morning. Moderate to breezy southeast 
winds are anticipated during the late morning into the afternoon 
hours on Monday. VFR conditions are expected to return late Monday 
morning into the afternoon. 

&&

.PREV DISCUSSION... /issued 241 PM CDT Sun Mar 24 2019/ 

SHORT TERM (Tonight through Monday Night):Clouds held strong today 
with an uptick in frictional convergence upstream along the Mexican 
coast, however, the clouds didn't impact temperatures much. As of 
writing this AFD we have hit 82F here at KBRO. Where sun was able to 
break out more frequently (e.g. west of I69C), temperatures have 
warmed into the middle 80s to near 90 out at Falcon Lake.

Clouds are progged to hold tight tonight with an extremely subtle H5 
impulse moving eastward "down wind" if you will of the trough 
lifting out across the Great Lakes as well as a weak LLJ that should 
continue to pump plenty of low level moisture into the region. 
Additionally, SREF progs are indicating a pretty high probability 
for marine fog tonight, however, noticed this AM's run was very 
overdone. Aviation stat guidance also indicates some reduction in 
visibility, however, don't buy the <1 mile visibilities at this 
time. True, marine fog may develop as 70+ dew points move over a mid 
60s sea surface, however, winds are a bit on the higher side for a 
more widespread dense fog event. Not to mention sea surfaces are 
gradually rising now. 

On Monday expect partly to mostly cloudy skies to persist with some 
breaks in the afternoon behind the earlier mentioned impulse.
Given the blends poor performance over the last couple of days, went 
a degree or two above guidance on Monday out ahead of our next cold 
front...though no heat spike as winds do not transition westerly 
until perhaps early morning Tuesday. 

LONG TERM (Tuesday through Sunday):Mid level ridging dominates 
South Texas in wake of a weak cold front passage Tuesday morning. 
The ridge will be slow to move east with seasonal and tranquil 
conditions prevailing through Thursday. Models suggest broad low 
pressure trough developing over the Rockies and Plains States next
Friday through Sunday which will likely result in warm and breezy
to windy conditions with a possible cold front and a chance of  
rain next Saturday night or Sunday. 

Will trend slightly cooler, favoring the NAM/ECMWF, with 
Tuesday's cold front with a thick overcast lingering through the 
day and a cool northeast to east flow flowing around the broad 
surface high extending from the Midwest. Rain chances still look 
limited, with best chance over the Western counties, with the mid
level trough well removed from South Texas. Limited forcing, with
better lift in the west, will provide the chance of a thunderstorm
or two. Surface ridge moves east as the mid level ridge builds 
over Texas with southerly flow returning/increasing and a warming 
trend commencing for the remainder of the work week and into 
Saturday. Both the GFS and ECMWF develop a strong and cold upper 
trough over the Rockies/Plains States next weekend. Even with the 
two deterministic models having different placement of the upper 
trough they both move a cold front through South Texas next 
Sunday. Confidence in timing and strength is near average due to 
both models showing the same trend. 

MARINE:(Tonight through Monday Night): Light to moderate 
southeasterly flow expected to prevail. Overall, rather benign 
marine conditions expected with wave heights 2 to 4 feet with some 
slightly higher waves offshore. A weak front will approach the 
region toward the end of the cycle, however, the pressure gradient 
through Tuesday morning should remain light (keeping winds moderate 
to best or below cautionary wording). Finally, there is a signal for 
nearshore marine fog tonight and early Monday. That said, winds 
should remain around 10 to 13 knots, which should help in limiting 
fog somewhat.

Tuesday through Friday: A cold front Tuesday ushers in a short- 
lived moderate northeast flow and moderately high sea with exercise
caution conditions likely. Surface winds quickly turn east to 
southeast by Wednesday with a gradual increase through the end of 
the work week as high pressure settles over the Eastern Gulf and 
interacts with lower pressure developing over the Plains States. 
The pressure gradient may get strong enough Thursday night and 
Friday for winds and seas to approach SCEC levels with some 
probability of winds reaching SCA. 

&&

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

$$

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