942
FXUS64 KBRO 092220 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
520 PM CDT Sun Mar 9 2025

...New AVIATION...

.SHORT TERM...
(Tonight through Monday night)
Issued at 241 PM CDT Sun Mar 9 2025

Key Message:

-Below normal temperatures through Monday.

Plenty of sunshine and comfortable temperatures will be the main
story of the short term period. For the remainder of today, breezy
northerly winds will continue this afternoon. Dry air continues to
filter into the region, and along with the breezy conditions has
lead to a Fire Danger Statement for all of Deep South Texas away
from the Islands until 7 PM tonight. Winds will begin to decrease
later this afternoon and evening.

Temperatures remain below normal for this time of year with todays
highs in the low to mid 70s, with only slight warming for Monday.
Overnight lows tonight will be quite chilly ranging from the low 40s
in the northern Ranchlands to upper 40s in the RGV. Monday night
will only be around 5 degrees warmer in most locations for lows.

&&

.LONG TERM...
(Tuesday through next Sunday)
Issued at 241 PM CDT Sun Mar 9 2025

Key Messages:

* Above normal temperatures through the forecast period, with highs
  in the 90s for Wednesday and Thursday, and triple digits for
  Friday.

* A strong cold front will move through on Friday that will bring
  very dry air to the region that is currently expected to bring the
  minimum relative humidity to under 20% Friday through next Sunday.

The start of the long term forecast will begin with nearly upper
level zonal flow and a developing weak surface high pressure over
Deep South Texas and the Rio Grande Valley. A weak trough is
expected to move over the desert southwest and push a weak cold
front into the northwestern portion of the Upper Valley. There is a
possibility of a dry line move through the region ahead of the weak
cold front during the afternoon on Wednesday, as the relative
humidity shows a sharp change. The relative humidity for the Upper
Valley is expected to also be low (under 20%) for Thursday as well.
Raising some Fire Weather concerns that will be discussed below.
While the pattern overall will continue to see above normal
temperatures, the high temperatures for Wednesday and Thursday are
generally expected to be in the low to mid 90s for most of the the
region, except along the coast where the high temperatures will be
in the upper 80s.

Another stronger upper level trough is expected to push a cold front
through the region sometime during the day on Friday. This could
lead to another potential heat spike with most of the model guidance
showing that the high temperatures for most of the region could get
into the triple digits. While there is no precipitation expected
with this front, there will be plenty of dry air behind it, that
will see relative humidity values very low. This will lead to
another period of Fire Weather concerns, which will also be
discussed in the Fire Weather Section below.

After the front, clear skies and slightly cooler temperatures with
highs in the 80s are expected for the weekend. While the generally
weak northerly winds should last through Saturday and into the early
part of Sunday. The winds should turn back towards the east by
Sunday evening.

&&

.AVIATION...
(00Z TAFS)
Issued at 515 PM CDT Sun Mar 9 2025

Mainly clear skies and VFR conditions are expected to prevail
throughout the 00 Z TAF cycle. Gusty north-northwesterly winds,
currently being reported, are expected to lighten after sunset
this evening, giving way to generally light, or near calm, winds
overnight. Winds are expected to remain light to gentle, out of
the north, during the daytime tomorrow, transitioning to
northeast during the late afternoon and evening hours.

&&

.MARINE...
Issued at 241 PM CDT Sun Mar 9 2025

Now through Monday night...A Small Craft Advisory is in effect
into this afternoon for the nearshore Gulf waters and Laguna Madre
and into this evening for the offshore waters. As winds decrease
this evening, seas will respond with favorable conditions
returning to all waters overnight and prevail through Monday.

Tuesday through Next Sunday...While a generally favorable marine
conditions are expected to last through the period, there are a few
time periods to be concerned for. The first of which is on Wednesday
as the pressure gradient tightens up with a weak cold front stalling
out to the northwest of the Lower Texas Coast and high pressure over
the Gulf waters. This could most likely lead to adverse
southeasterly winds that will require Small Craft Exercise Caution.
The second period of concern will be Friday and Saturday. A stronger
cold front is expected to push through the Lower Texas Coast and
likely bring more adverse conditions that will result in more Small
Craft Exercise Caution that will occur before and after the frontal
passage. Outside of those periods, generally light to moderate
winds and moderate seas are expected to persist.

&&

.FIRE WEATHER...
Issued at 241 PM CDT Sun Mar 9 2025

Wednesday through Next Sunday....There are a few periods of
concern for elevated Fire Weather concerns. The first of which is
Wendesday and Thursday, as the relative humidity values in the
Upper Valley are expected to fall below 20%. However currently,
the 20-foot winds are under 10 mph currently, which would limit
the spread of any developing wild fires. The next period of
concern would be Friday through Sunday, as the minimum relative
humidity values are currently expected to be under 20% for most of
Deep South Texas and the Rio Grande Valley. The only exception to
this is right along the coast and on the barrier island. While
the 20-foot winds are generally under 15 mph for most of this
timeframe. However, Saturday afternoon the current model forecast
does have the 20-foot winds very close to 15 mph for most of the
area. Further forecast shifts will need to continue to monitor
model trends in case of any changes.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             49  74  53  77 /   0   0   0   0
HARLINGEN               45  77  49  82 /   0   0   0   0
MCALLEN                 49  81  53  86 /   0   0   0   0
RIO GRANDE CITY         46  79  51  86 /   0   0   0   0
SOUTH PADRE ISLAND      55  66  57  71 /   0   0   0   0
BAYVIEW/PORT ISABEL     49  71  53  76 /   0   0   0   0

&&

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

GM...Small Craft Advisory until 9 PM CDT this evening for GMZ170-175.

&&

$$

SHORT TERM...68-McGinnis
LONG TERM....64-Katz
AVIATION...65-Irish