Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 240606 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
106 AM CDT Wed May 24 2017

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

&&

.AVIATION...VFR conditions will prevail across Deep South Texas
for the next 24 hours as surface high pressure builds across the
area. North winds will continue overnight and this morning due to
the passage of a weak cold front. Winds will gradually veer to
the east and southeast later this afternoon into this evening as
surface high pressure moves east.

&&

.PREV DISCUSSION... /issued 701 PM CDT Tue May 23 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Main aviation concerns tonight will be the potential
for strong storms developing along a southward-moving cold front.
Many storms are ongoing in the Corpus Christi area and may move
into the Rio Grande Valley late tonight. Have kept a TEMPO group
for all three airports for low visibilities and heavy rain, though
confidence is low to moderate on direct impacts to airport
terminals. Behind the front, clouds will clear and VFR conditions
will be expected on Wednesday.

PREV DISCUSSION... /issued 242 PM CDT Tue May 23 2017/

.Slight risk of severe weather across the Rio Grande valley and
northern ranchlands tonight...

Short Term (Tonight through Wednesday night): The combination of
a 500mb trough across the central United States and a weak cold
front moving through the CWA tonight will allow scattered showers
and thunderstorms...some possibly strong to severe...to develop
across the northern ranchlands and upper Rio Grande valley this
evening and across the middle and lower Rio Grande valley late
this evening into early Wed morning. The greatest threats for
severe weather will be large hail and damaging winds. In
addition...precipitable water values are near 2 inches and heavy
rainfall will likely develop with storms tonight. Localized flash
flooding is possible with slow moving storms or where storms
train over the same areas especially across portions of the
western ranchlands and upper Rio Grande valley where significant
rainfall fell Sun night. Will go with a high chance of showers
and thunderstorms tonight as the atmosphere will be highly
unstable and lapse rates will steepen this evening per the latest
NAM forecast soundings. Will word some storms possibly severe
tonight with large hail and damaging winds. Will also word heavy
rainfall with some thunderstorms tonight.

Rain chances will diminish late tonight into early Wed morning as
drier air filters into the northern ranchlands in the wake of the
front tonight. Temperatures will be slightly cooler Wed afternoon
compared to the previous couple of days but will still be very
warm across the CWA. An onshore flow will quickly return Wed night
as surface high pressure over the Rio Grande valley and northeast
Mexico moves eastward.

LONG TERM (Thursday through Tuesday): 500 hPa ridging fro north
central Mexico to Minnesota and 1012 mb high pressure over the
Gulf will spell relatively quiet weather for deep south Texas and
the RGV Thursday. As the ridge flattens and drifts east and
overhead, temps through Sunday will trend slowly higher, becoming
several degrees above normal. Look for a mix of clouds and sun
through the weekend, moderate to breezy southeast winds and high
temperatures in the 90s to near 100 with low temperatures well
into the 70s if not near 80.

By Sunday, with a mean trough over the upper Midwest and ridging
again building over the western United States, high pressure will
spill southeast from the upper northwest United States, pushing
into central Texas. A front will make its way into the CWA on
Monday, bringing slightly lower temps and an increase in rain
chances, particularly for the northwest sector, where convection
may fire late Monday night into Tuesday morning

MARINE:
Tonight through Wednesday night: Seas were near 4 feet with east
to northeast winds near 12 knots at buoy020 early this afternoon.
Winds will shift to the north and increase across the coastal
waters late tonight as a weak cold front moves offshore the lower
Texas coast this evening. SCEC conditions will develop across the
lower Texas coast tonight and continue Wednesday as high pressure
builds across the northwest Gulf of Mexico in the wake of the
front. Moderate to strong north winds late tonight into early
Wednesday will diminish Wed afternoon as high pressure settles
across the lower TX coast. Light to moderate north to northeast
winds Wed afternoon will veer to the southeast Wed night as the
surface ridge moves eastward.

Thursday through Sunday night: Persistent high pressure over the
Gulf will combine with equally persistent lower pressure over the
southern High Plains to produce moderate to fresh or low end
strong southeast to south winds and moderate to high seas. Small
craft should exercise caution to low end small craft advisory
conditions will be common through this period.

&&

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

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

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