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Area Forecast Discussion (AFD)

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

FXUS64 KBRO 242021

Area Forecast Discussion
National Weather Service Brownsville TX
321 PM CDT Thu May 24 2018

.SHORT TERM (Tonight through Friday Night): The afternoon sea
breeze today fired a few early afternoon showers and t-storms near
the coastline. However as the sea breeze pushes farther west and
encounters drier and more stable air expect the conv coverage to
be pretty minimal. Expect another sea breeze setting up tomorrow
as the daytime heating interacts with the fairly weak surface wind
flow pattern. Expect the overall moisture and instability over the
RGV to gradually decrease throughout the short term period which
would tend to limit the conv potential for tomorrow. Isold cells
cannot be ruled out but my overall confidence in the conv
potential heading into Fri is pretty low as 500 mb ridging is
expected to continue gradually building east over the TX coastline
through Fri Night. 

For temps will stick close to persistence for temps throughout the
short term. This is a little closer but still warmer than the
ECMWF temp guidance which is warmer than both the NAM and GFS. 

.LONG TERM (Saturday through Thursday): The CWFA will be squeezed
between upper level trough across the northeast Gulf and a strong
ridge building slowly eastward closer to our area through early
next week. This northerly/northwesterly flow aloft should remain
very dry. Little in the way of clouds and precipitation can be
expected through the upcoming holiday weekend. 

We are still watching the area of disturbed weather very close to
the Yucatan, however, with a strong H5 trough this should provide
more than enough weakness in the subtropical high across the 
Bahamas to allow the storm to move generally northward toward the 
central Gulf Coast. Track forecast of whatever eventually shakes
out from this feature is pretty high confidence so overall the
confidence in rain chances (or the lack thereof) in the long term
are overall fairly high confidence. With the 594dam heat bubble 
parked just to our south with the ridge axis nearly overhead by 
Tuesday, expect temperatures to approach the upper 90s to 
exceeding the 100 degree mark, especially across the western CWFA.


.MARINE (Tonight through Friday Night): Surface ridging over the 
southeastern United States will interact with the broad surface 
low pressure area near the Yucatan Peninsula to maintain a light 
to moderate S-SE low level flow across the lower TX coastline 
throughout tomorrow night. No SCA conditions expected at this 

(Saturday through Thursday): The long term will start 
with all eyes focused on what evolves from the current area of 
disturbed weather near the east coast of the Yucatan. Surface 
pressure fields show a fairly relaxed gradient to start this 
weekend, however, we'll need to monitor wave heights as swells 
increase from the possible TC or subTC developing across the 
central Gulf of Mexico. As the TC/subTC moves northward and 
inland, southeasterly surface flow will develop. Overall, minus 
the swells generated from the possible TC/subTC, think that much 
of the long term marine will remain benign with only light to 
moderate winds.


BAYVIEW/PORT ISABEL  75  90  74  91 /   0   0   0   0 
BROWNSVILLE          75  95  75  94 /   0   0   0   0 
HARLINGEN            73  97  73  96 /   0   0   0   0 
MCALLEN              76 100  75 100 /   0   0   0   0 
RIO GRANDE CITY      75 100  74 101 /   0   0   0   0 
SOUTH PADRE ISLAND   77  82  77  84 /  20   0   0   0 




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Short Term/Aviation...60
Long Term...55