Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 091741 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1141 AM CST Fri Dec 9 2016

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

&&

.AVIATION...Moderate to breezy northwest to north winds and
cloudy skies will continue this afternoon as relatively shallow,
cool high pressure prevails over the area. MVFR conditions
expected at HRL/BRO with low end VFR ceilings at MFE through this
afternoon. Ceilings should lower again this evening with brief IFR
ceilings possible late. Winds will diminish tonight, becoming
light to moderate.

&&

.PREV DISCUSSION... /issued 546 AM CST Fri Dec 9 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Moderate to breezy northwest to north winds and
cloudy skies will continue today as relatively shallow, cool high
pressure spreads over the area, setting up an inversion up to
about 850 mb. MVFR conditions will be the rule with lowered
ceilings. Brief IFR ceilings will be possible late this evening.
Winds will diminish tonight, becoming light to moderate.

PREV DISCUSSION... /issued 358 AM CST Fri Dec 9 2016/

SHORT TERM (Today through Saturday): The short term will see a
slow recovery from the strong cold front of Thursday. Wind chill
values will bottom out through mid this morning along the coast
where a wind chill advisory is posted, mainly the result of
stronger winds there. High temperatures will be mostly in the mid
40s across the area, under cloudy skies and with light rain
possible. Winds will decrease to light tonight with slightly lower
temps, still in the 40s but with a few upper 30s possible across
the ranchlands and brush country. High temps Saturday will recover
into the 50s and 60s as a weak onshore flow develops. The mid
level pattern will remain somewhat zonal, with some drier air
upstream eroding the wedge of cooler, moister air from above, but
the developing onshore flow at lower levels will carry the day
with persistent, longer lasting moisture, at least through
Saturday or Saturday night.

LONG TERM (Saturday Night through Thursday):The cold blast
currently in place will only be a distant memory as we move into
the latter half of the weekend and into early next week. Once
again models are in fairly good agreement early on but show a lot
of inconsistency and uncertainty the latter portions of the long
term. Confidence remains below average for the Wed-Thu time frame
in regards to another shot of polar air.

Saturday night through Tuesday our CWA can expect a significant
warming trend as mid level flow becomes zonal with the subtropical
ridge building over NW-NC Mexico. Southerly surface winds return
and partly cloudy skies along with rising dew points should allow
for tempeatures to climb well into the 70s and lower 80s. Any
shower activity should keep over the Gulf waters with a deep layer
dry residing over South Texas.

The latter half of the forecast package remains a question mark
with the 00Z model output showing quite a bit of discrepancy with
another shot of polar air. Timing of the leading edge of this
potential cold shot is main question. The ECMWF now shows this
front moving into Deep South Texas as early as Wednesday,
yesterday it wasn`t even showing up on the map. The GFS remains
deeper and colder with the arctic airmass has now slowed down its
southern trajectory by 18 hours arriving sometime Thursday. With
plenty of uncertainty in the actual outcome and low confidence in
the model output will continue to resort to a model blend which
now brings the front through the region Wednesday night and
Thursday.

MARINE:(Today through Saturday): Will drop the remaining gale
warning on the Gulf this morning in favor of a small craft advisory
as winds slowly decrease due to high pressure spreading over the
area. Strong winds and elevated seas will persist today, though
winds over the Laguna should diminish enough to lower the advisory
there at some point today. North winds will veer to northeast and
then east through the short term as high pressure shifts east, and
as a weak surface trough develops along the TX coast. Wave heights
on the Gulf will remain above criteria into tonight or early
Saturday.

Saturday night through Monday...Marine conditions continue to
improve through the weekend with a moderate southerly wind
returning to coastal waters. Broad surface high pressure weakens
and mid level high pressure builds over the Bay of Campeche and
NW Mexico providing a tranquil weather pattern for the Western
Gulf of Mexico the first half of next week.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 6 PM CST this evening for
     GMZ130-132-135.

     Small Craft Advisory until 6 PM CST this evening for GMZ150-155-
     170-175.

&&

$$

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