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Area Forecast Discussion (AFD)

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

                            
000
FXUS64 KBRO 212340 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
640 PM CDT Sun Apr 21 2019

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

&&

.AVIATION...Southeast winds should continue to diminish just after
sunset, but will remain elevated with a few gusts over 20 mph
throughout the night. VFR conditions will continue with just some
thick upper-level cirrus clouds expected. Monday morning winds
will increase again, but should be a little weaker than today.
Models bring some low clouds in with some patches of MVFR ceilings,
but have kept a BKN deck at low-end VFR for the afternoon for 
now.

&&

.PREV DISCUSSION... /issued 344 PM CDT Sun Apr 21 2019/ 

SHORT TERM (Today through Monday): Another beautiful but breezy 
to windy day today with strong southeasterly winds across the lower 
Rio Grande Valley and lower Texas coast. Low pressure builds into 
the Plains as high pressure moves further east tonight, allowing the 
pressure gradient to stay strong into Monday, weakening only 
slightly through Monday night. A Wind Advisory was issued this 
morning across Cameron and Willacy counties, and carries through the 
afternoon, although, recent trends in observations have begun to 
fall just below criteria. Will hold onto headlines for the next 
shift to clean up as needed if these trends continue through late 
afternoon. 

Overall, winds stay elevated through the short term, with 
higher gusts diminishing this evening through late tonight and 
returning late Monday morning through Monday afternoon. At this 
time, do not expect Wind Advisories for tomorrow. Cloud cover 
increases as moisture returns to Deep South Texas, potentially 
knocking a couple of degrees off of the high temperature on Monday. 
Lows tonight dip only into the mid to upper 60s, with upper 60s to 
low 70s expected Monday night under better cloud cover and increased 
moisture. 

LONG TERM (Monday Night through Saturday): The large 500 mb
closed low over the western U.S./Mexico border will continue to
move east towards TX Tues and Tues Night. This closed low will
then push into central TX Wed and Wed Night increasing the 500 mb
PVA over much of the state. This closed low will then push NE out
of central TX into the ARK/LA/TX region by Thurs morning which
will in turn pull a fairly weak cold front through the region
early Thurs resulting a generally drier, but not necessarily 
cooler airmass over the RGV. After this 500 mb closed low exits 
the region a generally dry and hot 500 mb ridge axis will build 
over northern Mexico and the south central Plains States on Fri 
and Sat. 

Pretty decent deep layer moisture and MUCAPE values will be 
pooling ahead of the approaching 500 mb closed low which will 
increase the conv potential across the region late Wed into Wed 
Night. SPC continues to advertise south central TX for increased 
svr wx potential for Wed and Wed Night. So will maintain a decent 
mention of conv for midweek. 

The GFS and ECMWF models both are showing better agreement in the
timing and depth of the approaching 500 mb trough/closed low next
week. Run to run consistency with the GFS/ECMWF temps and pops are
coming into better agreement today versus the last couple of days.
So overall forecast confidence today has increased and remains
above average.  

MARINE (Now through Monday Night): High pressure moving east across 
the Gulf of Mexico and low pressure building in across the Plains 
has strengthened the pressure gradient, increasing winds along the 
lower Texas coast today. Small Craft Advisories continue into this 
evening while winds remain elevated. Gusts diminish this evening 
through tonight, allowing marine conditions to become less hazardous 
across the bay and nearshore Gulf of Mexico waters. Small craft 
should continue to exercise caution across all coastal waters 
tonight and Monday. Small Craft Advisories may be needed across Gulf 
of Mexico waters Monday afternoon through Monday night, especially 
offshore waters beyond 20 nautical miles. A Small Craft Advisory for 
Winds may be needed again tomorrow across the Laguna Madre during 
the afternoon hours. 

Tuesday through Friday Night: The strengthening PGF ahead of 
the approaching 500 mb closed next week will result in stronger 
S/SE surface winds along the lower TX coastline for much of the 
first half of the work week. This will likely result in some
borderline SCA conditions for Mon through Wed Night mainly for 
the lower TX Gulf waters. After the cold front moves through the 
region, the PGF will then weaken allowing for lower winds and seas
next Thurs and Fri. 

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 8 PM CDT this evening for 
     GMZ130-132-135.

     Small Craft Advisory until 8 PM CDT this evening for GMZ150-155.

&&

$$

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