Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 240452 AAB

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1052 PM CST Sun Feb 23 2020

...06z Aviation Update...

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


.AVIATION...Not too many changes made to the previous aviation
package. Ceilings will gradually lower through the night tonight,
dropping down to near IFR levels by sunrise Monday. Confidence
remains low on just how low the cloud bases will drop. Winds are
expected to veer from southeast to north through the morning and
into the early afternoon hours as a weak and dry cold front
approaches and pushes over the area. The cold front is forecast to
pass through between 16-19z, passing over MFE first and BRO last.
Clouds are expected to lift and clear to VFR after the front,
best guess...between 17-20z. Moderate to occasionally gusty winds
will accompany the front. Winds will then shift out of the
northeast by sunset, decreasing below 10 knots.


.PREV DISCUSSION... /issued 542 PM CST Sun Feb 23 2020/

..00z Aviation Update...

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...A bit of a complex aviation forecast over the next 24
hours. Current surface observations across Deep South Texas show
ceilings barely hanging onto VFR conditions. There could be
intermittent MVFR ceilings between 00z and midnight (06z) tonight.
For now, opted not to include a tempo group in the TAFs.
Confidence is relatively high that ceilings will drop to MVFR
around or slightly after midnight tonight as the nocturnal
inverstion sharpens overnight. Ceilings may even drop to IFR
levels, especially at BRO and HRL an hour or two before sunrise
Monday. Southeast winds will remain on the breezy side overnight
tonight, into Monday morning as low pressure across the Plains
continues to deepen and move eastward across Oklahoma. A weak cold
front will push through, moving northwest-to-southeast late
morning or early afternoon. Winds will veer from the south to
northwest, and eventually out of the north by mid afternoon
Monday. Low and mid-level clouds should quickly dissipate behind
the front as much drier air filters in, resulting in VFR
conditions. Timing of VFR will highly depend on exact timing of
the cold front, which should occur between 17-20z, clearing first
at MFE.

Overall forecast confidence: Medium

PREV DISCUSSION... /issued 242 PM CST Sun Feb 23 2020/

SHORT TERM (Now through Monday night): A storm system will move
across the Southern Plains, mainly Kansas/Oklahoma, tonight, with a
weak, low latitude front sweeping across Texas. The front will move
across the CWA from dawn to dusk with drier air in its wake.
Temperatures will still manage to creep into the 80s by mid Monday
afternoon, slowed primarily only across the ranchlands, where cooler
air will be offset by a mix of clouds and sun, as opposed to cloudier
skies expected farther east. Not much chance of rain with this one,
except for sparse showers across the extreme northeastern sections
of the CWA. Light northwest winds behind the front will become very
light Monday night, and low clouds may even work back in over the
southeast portion of the CWA by Tuesday morning since the front will
not make it very far offshore late Monday. Monday night temperatures
will be cooler, in the 50s and lower 60s, but not too much different
than normals for this time of year.

LONG TERM (Tuesday through Sunday):Cold mid-upper level trough
becomes established over the Central Plains as mid-level ridge
builds over the Pacific Northwest Tuesday and Wednesday. This
ushers in a potent but short-lived cold front for Tuesday night
with impacts through Thursday morning. Latest Global models their
respectable guidance remain in impeccable agreement and
consistency making for an above average confidence forecast.

Surface low wraps up over the Ohio Valley Tuesday with strengthening
surface ridge spreading south along the Rockies Front Range. Cold
air spills into Texas working its way through the RGV Tuesday
evening/night with some wind gusts approaching 35 mph especially
near the coast. Moderate and gusty northwest-north winds and
plummeting dew points Wednesday as GFS as well as NAM/ECMWF now
showing mean layer RH approaching 30 percent and winds at 12-20
mph. This will pose an elevated fire weather threat for much of
the region which is under Moderate to Severe Drought conditions.
Ridge settles over S TX Wed Night/Thu AM with clear skies, dry and
calm conditions allowing for excellent radiational cooling. 850mb
Temps indicated to be 1-3C and NBM guidance remains persistent on
mid 30s over the North and West Ranch lands and upper 30s to
lower 40s for the RGV (ECMWF is a few degrees colder). Conditions
continue trending in favor of a potential light freeze west of I

A trough in the east and Ridge in west looks to be the more reliable
500mb mid-level pattern Friday and next weekend. This favors a
continued dry and a slow warming trend for Deep South Texas. There
may be some hope for rain the beginning of March as models show a
larger storm tracking farther south.

MARINE:Now through Monday night...Moderate to breezy southeast to south
winds will prevail tonight and into Monday morning with small craft
should exercise caution conditions on the Gulf. Can`t rule out brief
SCA conditions on the Gulf, but didn`t have confidence to hoist the
flag just yet. Winds will decrease Monday ahead of a weak cold front
due Monday afternoon. Winds will shift to light to moderate north to
northeast Monday night behind the cold front, with moderate seas.

Tuesday through Friday...Weak pressure gradient Tuesday
with a cold front poised over South Texas. The front makes it push
offshore Tuesday evening/night as a Low pressure trough over the
Central Plains makes it farthest point South. Modest high pressure
builds into Texas with north winds increasing through Wednesday
morning. Models continue to suggest the potential for gale force
gust Tue night/early Wednesday with Small Craft Advisories
continuing through Wednesday for the Laguna Madre and Thursday
morning for the Gulf waters. The high pressure ridge builds over the
Western Gulf Thursday night and Friday with rapidly improving




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