Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 272333 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
533 PM CST Sun Nov 27 2022

...New AVIATION...

.SHORT TERM...
(Tonight through Monday night)
Issued at 245 PM CST Sun Nov 27 2022

A weak cold front currently moving through Central and East TX will
stall across the extreme northern portions of the CWA tonight.
Enhanced boundary layer convergence along with a a very marginal
moisture profile will lead to the potential for isolated showers in
the vicinity of the front, mainly along coastal zones and the
adjacent waters.  The net effect for most of the CWA will be to keep
winds on the light side tonight. This along with the dry air above
the boundary layer and clear skies will lead to excellent
radiational cooling conditions. The SREF/HRRR/RAP solutions and
BUFKIT data continue to point to widespread fog tonight developing
due to these radiational conditions.  Areas of dense fog, especially
across the mid/upper valley region and the northern ranchlands,
looks like a very good possibility.  A Dense Fog Advisory will most
likely be needed for most of the CWA from the late evening through
Monday morning.

Low clouds will increase throughout the day on Monday and especially
on Monday night as the low level flow strengthens and backs to a
more southeasterly direction.  Despite the increase in cloud cover
on Monday, highs should be at or slightly warmer than today`s highs
for most of the CWA.  Overnight lows will be much milder on Monday
night due to clouds and a persistent southeast flow all night. The
potential for fog looks a lot lower for these reasons.  Moisture
advection and convergence will once again lead to some isolated
shower activity for mainly the coastal zones for Monday night.

&&

.LONG TERM...
(Tuesday through next Sunday)
Issued at 245 PM CST Sun Nov 27 2022

Forecast and model philosophies remain in good agreement with this
medium to long range forecast package an update to the previous
package. General mean 500mb synoptic set- up across the CONUS
continues to indicate a west to southwest flow flow with troughs
along both the Pacific and Atlantic coast and broad subtropical
ridge becoming anchored east to west from Cuba across the Gulf of
Mexico through South Texas and N Mexico.

As for the forecast trends Tuesday remains on track to be the warmest
and windy day of the week with strong southerly flow becoming
established in advance of a deepening mid-level trough over the
Rockies. Models continue to show a low-level jet 30-40 kts which
will translate to 20-30 mph with higher gusts. At this time, most
model guidance keep surface winds shy of wind advisory (30+,
gusts >39 mph. Temperatures warm up nicely and with 850mb temps
20-22C there is more confidence of some locations seeing maximums
reach the upper 80s!

Cold front still on tap for late Wednesday morning with model
consensus continuing to increase pops ahead and behind the front.
Confidence is low for thunderstorm chances upon the fronts arrival
in the RGV, however isentropic upglide intensifies steadily in wake
of the front peaking Thursday setting up a potential high pop low
qpf scenario. Coastal trough develops off the lower coast Thursday
with surface ridge nosing into South Texas setting the stage for the
overrunning event similar to this past Friday. Condensation pressure
deficits become very narrow along the 295-300K pressure levels and
forecast point sounding continues to show 950-800mb level saturation.
In a nut shell, the period Wed-Thu will see temperatures falling
behind the front Wednesday afternoon and a increasingly wet and
fairly cool Wednesday night and Thursday. Continued to advertise
light rain and drizzle for most of Thursday with highs struggling
to reach the lower 60s or even 60 degrees out west. Would not be
surprised to see future model runs continue to trend higher on
pops and lower temperatures, albeit a few degrees.

Subtropical ridge becomes parked over the region Friday and next
weekend with southeast surface flow returning. Coastal trough
weakens as the southeast winds become established leading to
Warmer and benign weather.

&&

.AVIATION...
(00Z TAFS)
Issued at 526 PM CST Sun Nov 27 2022

VFR conditions and moderate southeasterly winds will persist for
the next couple of hours before winds drop off and LIFR fog takes
over at all three TAF sites. Onset of dense fog should be around
5Z to 8Z tonight and it likely won`t mix out until 16Z to 18Z and
by that point, an MVFR cloud deck is expected to form. Winds will
be light and variable overnight and remain light through much of
Monday.

&&

.MARINE...
Issued at 245 PM CST Sun Nov 27 2022

Tonight through Monday night...Weak southerly flow ahead of a
cold front will prevail tonight across the Lower Texas coastal
waters. The cold front will stall across the northern waters by
Monday morning. Initially a northeast flow on Monday morning will
continue to back and slowly strengthen through Monday night as low
pressure organizes and develops across the plains. Seas initially
will be 2-3 feet but will gradually respond by Monday night due
to the strengthening south to southeast gradient. Isolated to
scattered showers will be possible on Monday and Monday night due
to increased moisture advection and convergence.

Tuesday through Friday...Fresh southerly flow Tuesday in
advance of a cold front over north Texas may become strong enough to
warrant small craft advisories on the Laguna for the daytime
spreading offshore late in the day and the evening. Winds
temporarily diminish Tuesday night and early Wednesday with the
front surging through late Wednesday morning and afternoon. Pressure
gradient strengthens rapidly with strong to near gale force
sustained winds Wednesday afternoon and evening. There is above
average confidence for a gale conditions developing for at least 6
to 9 hours. Hazardous seas develop and likely to persist well into
Thursday.  Improving conditions Thursday night and Friday as surface
ridge north of the Gulf coast passes to the east weakening the
pressure gradient. Showers and an isolated thunderstorm may
accompany the front with light rain, drizzle and marine fog
developing Wednesday night and Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             61  81  70  85 /  20  20  10   0
HARLINGEN               58  81  68  85 /  10  10  10   0
MCALLEN                 59  81  68  87 /   0   0   0   0
RIO GRANDE CITY         54  79  65  85 /   0   0   0   0
SOUTH PADRE ISLAND      66  76  70  78 /  20  20  10   0
BAYVIEW/PORT ISABEL     62  78  68  82 /  10  10  10   0

&&

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

$$

SHORT TERM...80-MB
LONG TERM....59-GB
AVIATION...69-Farris


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