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Area Forecast Discussion (AFD)

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

FXUS64 KBRO 180838

Area Forecast Discussion
National Weather Service Brownsville TX
338 AM CDT Sat May 18 2019

SHORT TERM (Now through Sunday): A mid level trough over the Four 
Corners region will support pressure falls over the central High 
Plains today. The strengthening pressure gradient along the lower 
Texas coast will support moderate to breezy southeast winds this 
morning into the afternoon. A frontal system across the central U.S. 
along with a dryline across west Texas today, will provide showers 
and thunderstorms across the Plains extending south into central 
Texas. Most of the convection across Texas will move east during the 
day and should remain well north of the CWA. However, can not rule 
out a stray shower and thunderstorm across the northern ranchlands 
this afternoon. High temperatures this afternoon will range from the 
mid to upper 80s along the coast to the 90s inland under a mix of 
sun and clouds. Low temperatures tonight will fall into the mid to 
upper 70s under partly to mostly cloudy skies. High temperatures 
Sunday will range from the low to mid 80s at the beaches to the low 
to mid 90s inland, with a few upper 90s possible near Falcon Lake.  

A coastal flood statement for wave runup on the beaches remains in 
effect through 10 AM this morning due to a high astronomical tide 
around 5 AM coinciding with higher than normal observed tides.

.LONG TERM (Sunday Night through Friday): Unsettled weather
continues across the Plains through the long term period, with a 
front trying to sweep across the state on Tuesday. Models depict a
slight wind shift on Tuesday afternoon across the western 
counties until southeasterly flow takes back over by Tuesday 
night. Dry and warm flow aloft keeps Deep South Texas capped off 
through the period. The best chance for any isolated showers or 
thunderstorms remains with the seabreeze during mid to late 
afternoon hours, but have kept POPs at 10 percent or less through 
Friday. Due to strengthening pressure gradient, expect breezy to 
windy conditions on Monday into Tuesday, and breezy afternoons 
Wednesday through Friday. 

Heat Index values may top 100 degrees during afternoon hours
across the Rio Grande Valley Monday through Thursday, with Monday
and Wednesday afternoons falling just short of Heat Advisory
criteria across portions of the upper valley, in Starr and Zapata
counties. Mid 90s to near triple digit heat, coupled with
increased low level humidity, could create dangerous conditions
during the heat of the day for those exposed. Typical heat safety
tips messaging would apply this week. Remember to check on your
elderly friends, family, and neighbors. Make sure your pets or
livestock have shade and plenty of water. 


.MARINE (Now through Sunday): Strengthening low pressure over the
Plains will support moderate to occasionally strong southeast 
winds and elevated seas across the lower Texas coastal waters 
through the period. Small craft should exercise caution on the 
Laguna Madre and Gulf waters today into tonight, with low end 
small craft advisory conditions possible on the Gulf. Light to
moderate southeast winds and moderate seas will prevail across 
the coastal waters on Sunday as the pressure gradient weakens 
across the western Gulf.

Sunday Night through Friday: As more low pressure works into the
Plains, the pressure gradient strengthens into Monday, increasing
onshore flow along the lower Texas coast and creating hazardous
marine conditions across coastal waters. Moderate to strong
southeasterly winds will continue Monday night into Tuesday, with
occasional gusts to near gale force. Small Craft Advisories will
likely be needed through Tuesday. Small Craft Advisory conditions
may continue Wednesday through Friday across offshore Gulf of
Mexico waters, especially during the afternoon hours. Small Craft
Advisories for Wind are likely Monday and Tuesday across the
Laguna Madre, and may be possible during the afternoon hours of
Wednesday through Friday. 


BAYVIEW/PORT ISABEL  88  78  88  78 /  10   0   0  10 
BROWNSVILLE          90  79  91  79 /   0   0  10  10 
HARLINGEN            92  78  93  78 /   0   0  10  10 
MCALLEN              95  78  95  79 /   0   0  10  10 
RIO GRANDE CITY      97  77  95  78 /   0   0  10  10 
SOUTH PADRE ISLAND   81  78  83  78 /  10  10   0  10 




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