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Area Forecast Discussion (AFD)

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

FXUS64 KBRO 200846

Area Forecast Discussion
National Weather Service Brownsville TX
346 AM CDT Wed Mar 20 2019

.SHORT TERM (Now through Thursday): Light rain and drizzle is 
overspreading most of Deep South Texas and the Rio Grande Valley 
right now courtesy of a deep easterly flow and a weak inverted 
surface trough. Scattered areas of light precipitation will 
continue today, but become isolated tonight, as the trough 
prevails before dissipating due to the influence of high pressure.
An influx of drier air and more dominant surface high pressure 
will lead to dry weather on Thursday. Although significant 
cloudiness will result in below normal temperatures today, 
thinning cloudiness tonight and Thursday will allow for more near 
normal temperatures for that time period. 

.LONG TERM (Thursday Night through Tuesday): 500mb ridge across
Texas Thursday will shift eastward as a 500mb trough moves across
the Rockies Friday. Low to mid level moisture will increase across
northeast Mexico into west Texas Thursday into Friday with
convection developing to the northwest and southwest of the CWA
Friday. Isolated to scattered showers and thunderstorms will move
across portions of deep south Texas Fri night into Sat morning
before a zonal flow develops across south Texas Sat afternoon into
Sat evening. In addition...some drier air aloft will move across
the area Sat afternoon into Sat night. Drier air will continue to
move into southwest Texas Sunday and rain chances will be limited
into early next week. A cold front is progged to move through the
Rio Grande valley Mon night into Tuesday morning and isolated 
showers will develop across the area as low level moisture pools 
along and ahead of the front. Surface high pressure will build
into deep south Texas in the wake of the cold front Tuesday. 

.MARINE (Now through Thursday): Buoy 42020 reported east-southeast 
winds around 18 knots gusting to around 21 knots with seas slightly 
over 6.5 feet with a period of 8 seconds at 250 CDT/750 UTC. Large 
swells approaching the Lower Texas Coast from the east will 
gradually subside during the forecast period. However, enough swell 
will remain to warrant Small Craft Exercise Caution and Small Craft 
Advisory for Hazardous Seas today and Small Craft Exercise Caution 
solely tonight. More moderate wind and sea conditions are likely on 

Thursday night through Sunday...Light east to southeast winds will
prevail across the coastal waters Thurs night before increasing
slightly Friday as surface high pressure across the northwest Gulf
of Mexico moves eastward and the pressure gradient increases
across the lower Texas coast slightly. Moderate east to southeast
winds should prevail across the western Gulf Friday before veering
to the southeast Saturday and continuing through Sunday. 

BAYVIEW/PORT ISABEL  71  60  72  62 /  40  20   0  10 
BROWNSVILLE          73  60  74  61 /  40  20   0  10 
HARLINGEN            72  59  74  59 /  40  20   0  10 
MCALLEN              72  60  74  60 /  40  20   0  10 
RIO GRANDE CITY      73  59  73  60 /  40  20   0  10 
SOUTH PADRE ISLAND   69  61  72  63 /  40  20   0  10 

GM...Small Craft Advisory for hazardous seas until 7 PM CDT this 
     evening for GMZ170-175.

     Small Craft Advisory for hazardous seas until 7 AM CDT this 
     morning for GMZ150-155.


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