765 
FXUS64 KBRO 021715 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1215 PM CDT Wed Jun 2 2021

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

&&ndicating

.AVIATION...Current radar is showing a few rain showers 
developing across the border and moving north into the RGV. These 
showers will affect BRO, MFE and HRL respectively over the next 
few hours before conditions dry out again. VFR conditions are 
expected to continue this afternoon into tonight, with brief 
pockets of MVFR across all aerodromes. By daybreak chances of 
showers and thunderstorms will increase across all terminals with 
VFR continuing to prevail though MVFR conditions will be possible 
with the passing rain and storms. Southeasterly winds will 
continue to remain light to moderate.

&&

.PREV DISCUSSION... /issued 628 AM CDT Wed Jun 2 2021/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Convective models continue to keep Deep South Texas
generally rain-free until this afternoon, with a slight chance of
some showers and thunderstorms forming along the sea breeze, so 
have kept PROB30 groups for this afternoon and early evening 
hours mainly for MFE. Otherwise, light to moderate southeasterly 
winds and VFR conditions are expected to prevail through the TAF 
period.

PREV DISCUSSION... /issued 417 AM CDT Wed Jun 2 2021/ 

SHORT TERM (Now through Thursday): A positively tilted trough will 
swing towards the Mississippi River Valley through the short term 
while a cutoff low spins over Baja California. A series of upper 
level disturbances push out ahead of this low and move over Deep 
South Texas, bringing a slight chance to chance of showers and 
thunderstorms mostly for our western counties today and tomorrow. 
However, convective trends are beginning to downplay today with 
brief sea breeze activity and highlight the better chances on 
Thursday when there is better upper level support. This upper level 
support looks like it will spark convection across South Central 
Texas and Northeast Mexico Thursday morning and then possibly allow 
these systems to merge with preexisting convective boundaries and 
move into our CWA during the day. With this pattern and precipitable 
water values near 2 inches on Thursday, along with nearly saturated 
soils from the recent rainfall, WPC has included our entire CWA in a 
Marginal Risk of Excessive Rain on Thursday as flash flooding will 
be possible with this activity. As of now, these storms are not 
expected to be severe, so the main threat will be the potential for 
flash flooding.

Increased cloud cover early to mid week along with any precipitation 
will help to keep temperatures at or slightly below normal through 
the period. In addition, light southeast winds are expected to 
persist as the pressure gradient remains slack.

LONG TERM (Thursday Night through Tuesday): 500 mb low pressure
transitioning from the Baja Peninsula to the Lone Star State will
provide Deep South Texas and the Rio Grande Valley with robust 
chances for showers and thunderstorms Thursday night through
Saturday. Rain chances will then scale back for the remainder of
the forecast as the mid-level low shifts farther north and a 500
mb ridge begins to nose-in from the west. However, some model
guidance suggests that ample precipitation will persist for the
entire long term period of the forecast. In fact, mesoscale
convective systems may pass through the BRO CWFA Sunday night and
again on Tuesday in the base of a deep 500 mb trough. These
possible changes to the current forecast will need to be monitored
by successive shifts. Otherwise, the nearly persistent chance of
rain and associated significant cloud cover will keep daytime high
and overnight low temperatures around normal values for this time
of year. 

MARINE (Now through Thursday): Most of the short term will be 
characterized by favorable marine conditions with light to moderate 
southeasterly winds and low to moderate seas. However, there is a 
chance for some isolated to scattered showers and thunderstorms on 
Thursday that may reduce visibility, agitate the seas, and bring a 
chance for cloud to water lightning within these storms.

Thursday Night through Tuesday: Favorable marine conditions for a
majority of the period will become slightly more adverse for 
Monday and Tuesday as swell approaches the Lower Texas Coast from
the southern Gulf of Mexico. Small Craft Exercise Caution may be 
needed Monday and Tuesday for the Gulf of Mexico waters, mainly
between 20 and 60 nautical miles offshore. 

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  87  75  86  74 /  10  20  50  40 
BROWNSVILLE          90  76  88  75 /  20  20  50  40 
HARLINGEN            90  74  88  73 /  20  20  50  40 
MCALLEN              91  74  88  73 /  20  30  60  40 
RIO GRANDE CITY      92  73  89  71 /  30  50  60  40 
SOUTH PADRE ISLAND   83  77  83  76 /  10  10  50  30 

&&

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

$$

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HTTP://WEATHER.GOV/RGV

68-McGinnis/Aviation