AFOS product AFDBRO
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Displaying AFOS PIL: AFDBRO
Product Timestamp: 2021-08-21 19:41 UTC

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755 
FXUS64 KBRO 211941
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
241 PM CDT Sat Aug 21 2021

.SHORT TERM (Tonight through Sunday Night): Spotty showers, with 
an occasional rumble of thunder, have developed since late morning
over much of the area. These have been somewhat lesser in 
coverage than forecast, however, as any moisture surge from 
distant TC Grace has been largely suppressed to our south by a 
592-dam high at 500mb anchored over south-central Texas. Hence, 
sunshine has allowed heat indices to climb into the 105-110F range
once again, though this is certainly not unusual for mid-late 
August.

Have downgraded the Coastal Flood Advisory to a Coastal Flood 
Statement valid until 7 PM CDT; see earlier AFD update for details. 
Elected to keep the High Surf Advisory (through at least 7 PM) and 
Rip Current Statement (through at least 7 AM Sunday) going, with 
nearby buoys reporting 10-12 second period swell and reports of 
strong rips near the South Padre Island Jetties this morning.

Precip chances should end by early evening with the loss of daytime 
heating. Another warm, humid night is in store. Some guidance 
hinting at minor visibility reductions, to 4-6 miles, over 
interior portions of Hidalgo/Brooks/Jim Hogg counties, but 
confidence in this is pretty low at this time.

High pressure aloft remains in control for Sunday, with high 
temperatures similar to today's readings, or perhaps a degree or two 
higher. Some mixing of drier air aloft should yield afternoon 
dewpoints ranging from the low-mid 60s over Zapata to the lower 70s 
in Brownsville. This would act to keep heat indices below Heat 
Advisory criterion (of 111F) again, though it will feel rather hot 
out in the sun.

Little change for Sunday night, though model guidance (particularly 
the NAM) hints at a slight deepening of moisture over the southern 
coastal waters and lower RGV, which could lead to a nighttime shower 
or two, most likely after midnight.


.LONG TERM (Monday through Saturday): A ridge of high pressure 
will continue to dominate over the region for start of the long 
term. While this will lead to subsidence across the region, weak 
perturbations on the southern side of the ridge will allow a slight 
chance of showers and thunderstorms to affect mainly coastal 
counties through Tuesday. As this ridge begins to break down on 
Wednesday, chances for precipitation increases across the CWA 
through Saturday, especially each afternoon. Forecast guidance shows 
PWATS under 2 inches so rain amounts should remain fairly light. 
Temperatures will remain seasonal through Tuesday but with the 
increase chances for showers/thunderstorms and cloud cover Wednesday 
through Saturday temperatures will likely remain just below normal 
but heat indices will still reach 103 to 110 most afternoons.

&&

.MARINE(Now through Sunday Night): Swells originating from then 
Hurricane Grace's trek across the Bay of Campeche still keeping 
seas stubbornly hazardous on the Gulf waters, with the Small Craft
Advisory in effect until 1 AM Sunday. Latest report from Buoy 
42020, as of 1840 UTC/1:40 PM CDT, is 7 ft. swells (8 ft. combined
seas) with a dominant period of 11 sec. TABS-K, further south, is
at 10 ft. seas with similar period. Seas should gradually subside
to sub-hazardous levels by the pre-dawn hours of Sunday, with 
improving trend continuing through Sunday night with moderate SE 
winds and seas down to ~4 ft. by 1200 UTC Monday due to modest 
surface high pressure taking control over the Gulf.

Monday through Thursday...Generally favorable marine 
conditions are expected to prevail as the swell from Grace subsides 
through the period. Winds will remain light to moderate out of the 
east or southeast and wave heights will be around 2 to 4 feet on the 
Gulf. Showers and thunderstorms are possible through the period that 
could lead to localized increased winds and elevated seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  78  92  78  92 /  10  10  20  20 
BROWNSVILLE          79  96  79  95 /  10  10  20  20 
HARLINGEN            76  96  77  95 /  10  10  10  10 
MCALLEN              76  98  76  98 /   0  10   0  10 
RIO GRANDE CITY      76 101  75 101 /  10  10   0  10 
SOUTH PADRE ISLAND   83  88  82  89 /  10  10  20  20 

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Sunday morning for TXZ256-257-351.

     High Surf Advisory until 7 PM CDT this evening for TXZ256-257-
     351.

GM...Small Craft Advisory until 1 AM CDT Sunday for GMZ150-155-170-
     175.

&&

$$

This product is also available on the web at:
https://weather.gov/rgv

53-Schroeder/Short Term
68-McGinnis/Long Term