618
FXUS64 KBRO 280841
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
341 AM CDT Sun Apr 28 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Today through Monday)
Issued at 317 AM CDT Sun Apr 28 2024

The start of the short term forecast period will see the influences
of an upper-level trough diminish over Deep South Texas and the Rio
Grande Valley, which will see the southwesterly flow aloft become
more zonal. SPC has Deep South Texas and the Rio Grande Valley in a
General Thunderstorm Outlook for today and Monday. However, part of
Northern Zapata is in a Marginal Risk (level 1 of 5) for severe
weather on Monday. For the showers and thunderstorms on Sunday, a
cold front and dry line upstream could merge north of the region.
While previous runs of CAMs models showed that theses showers and
thunderstorms could move into the Northern Ranchlands, the current
run does not reflect this happening. NBM does try to produce
isolated showers and thunderstorms for Northern Ranchlands still.
Looking into forecast soundings, shows that the environment stays
pretty capped leading an unfavorable environment for showers and
thunderstorms. Thus keeping rain chances at 20 percent for today.

For tomorrow, the situation is a bit different with an mid-level
shortwave potentially aiding in the development of showers and
thunderstorms. The atmosphere becomes marginally unstable with
MUCAPE around 2000 J/kg with model soundings indicating a weakening
of the cap later Monday, which would open a brief opportunity for
showers and thunderstorms to develop. However, a weak mid-level
ridge to the south of the area maintains mid-level dry air which
could hinder the development of the mentioned showers and thunderstorms.
Model and WPC QPF is also pretty limited, thus making the development
of showers and thunderstorms questionable at best for Monday.

As for temperatures, with the southerly to southeasterly flow at the
surface bringing in more humid, warm air, temperatures are expected
to stay pretty warm for the short term forecast period. High
temperatures for today and Monday are expected to be in the 90s for
most of the area, except along the coast and on the island. As for
the low temperatures for tonight, all of Deep South Texas and the
Rio Grande Valley is expected to be in the 70s.

Lastly, for anyone planning on going to the beach, High Risk of Rip
Currents has been extended through Monday on all the beaches as the
wave heights around 6 and swell period remain high around 8
seconds.


&&

.LONG TERM...
(Monday night through Saturday)
Issued at 317 AM CDT Sun Apr 28 2024

For the long term there will be a quasi-zonal midlevel flow
covering much of the CONUS with a few shortwaves riding over the
top of the subtropical ridge centered over Central Mexico. Farther
north low pressure troughs will be traversing the Rockies and
North and Central Plains with the strongest trough possibly
pushing a surface cold front into Central Texas next Friday and
Saturday. Southerly flow persist through the week with a moderate
pressure gradient maintaining a steady flow of low level moisture
(modest dew points in the U60s/M70s) and warm temperatures. Rain
chances continue to look limited with best chances Tuesday and
Wednesday and again Friday and Saturday. There remains uncertainty
on the timing of the shortwaves and areal coverage among latest
model projections with best overall coverage favoring Tuesday with
20-30% for most of the region with northern and Western areas of
Deep South Texas seeing best chances, albeit low Wednesday,
Friday- Saturday. It is May (in a few days) and the atmosphere is
likely to be in a conditional instability state. Forcing from the
above mention shortwaves or outflow from storms further north may
be sufficient to produce a few strong thunderstorms any of the
days mentioned. Some of the storms may be accompanied by gusty
winds, moderate to heavy rainfall and some hail.


Seasonal warm to hot temperatures with the region under the
influence of the northern edge of the subtropical ridge. Maximum
Temperature anomalies range from 2-5 degrees above early May
averages, while Minimums look to be a bit warmer 4-7 degrees above
mainly due to higher dew points as Gulf water temperatures are
already in the mid to upper 70s. Heat indices also, will show an
increase through mid week with maximums ranging 100-106 degrees.

&&

.AVIATION...
(06Z TAFS)
Issued at 1229 AM CDT Sun Apr 28 2024

Overall MVFR ceilings for the majority of the TAF period are
expected at all TAF sites. Some breaks of VFR are possible, not
expected to last for very long before MVFR ceilings return with
more low-level clouds tomorrow night. Breezy to windy conditions
are expected to continue overnight, but with the pressure gradient
expected to weaken, the winds should also diminish as well.

&&

.MARINE...
Issued at 317 AM CDT Sun Apr 28 2024

Today through Monday...A hazardous start as a Small Craft Advisory
remains in effect for the Gulf Waters through tomorrow morning.
While the pressure gradient will weaken allowing the the winds to
diminish as well, wave heights (7-8 feet) in the range of will
still take some time to subside, but should be more favorable
around mid-morning on Monday. Small Craft Exercise Caution for the
Laguna Madre today is likely while the winds are still expected
in the range of 15 to 20 knots.

Monday night through Saturday: Latest model projections show a
light to moderate pressure gradient for the coming week as surface
ridge weakens as it becomes centered east of Florida. Modest low
pressure will however continue over the Southern Plains allowing
for a moderate southeast wind and slight to moderate sea for much
of the period. Although, Small Craft Advisories are not expected,
periodic fresh winds to provide exercise caution at times.

&&


.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             92  77  91  77 /  10   0  20  10
HARLINGEN               94  74  92  74 /  10   0  20  10
MCALLEN                 94  76  94  77 /  10   0  20  10
RIO GRANDE CITY         94  73  94  75 /  10   0  30  10
SOUTH PADRE ISLAND      83  76  81  76 /   0   0  10  20
BAYVIEW/PORT ISABEL     91  75  87  75 /  10   0  20  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Monday evening for TXZ451-454-455.

GM...Small Craft Advisory until 7 AM CDT this morning for GMZ130-132-
     135.

     Small Craft Advisory until 7 AM CDT Monday for GMZ150-155-170-
     175.

&&

$$

SHORT TERM...64-Katz
LONG TERM....59-GB
AVIATION...64-Katz