081
FXUS64 KBRO 051036 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
536 AM CDT Wed Jun 5 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 257 AM CDT Wed Jun 5 2024

.SHORT TERM (Today through Thursday): Taking a page out of the
Mr. Peabody and Sherman playbook, will fire-up the "WABAC Machine"
to view forecast/observed Tuesday daytime high temperatures
across Deep South Texas and the Rio Grande Valley: PIL 96/98, BRO
99/99, HRL 99/100, MFE 102/98, EBG 102/100, TXW 100/97, BKS
104/102, HBV 102/100, and APY 106/106. Thus, it appears that model
guidance ran too hot for the interior inland portion of the BRO
CWFA, and too cool for the more coastal section.

Moving forward in time, 500 mb high pressure centered over the
Four Corners area of the United States will continue to provide
well above normal daytime high and overnight low temperatures
through the short term forecast period. NBM model guidance for
highs today and Thursday, when compared to recent observed highs,
appeared too hot, so manually lowered these about 2 to 3 degrees
across the entirety of Deep South Texas and the Rio Grande Valley.
Once algorithms were executed, the result was a HEAT ADVISORY for
all of the inland BRO CWFA except the island portions of Cameron,
Willacy, and Kenedy counties from noon until 8 PM today, with
another HEAT ADVISORY likely for tomorrow for the same, if not a
slightly smaller, area. An EXCESSIVE HEAT WARNING for Thursday
cannot be entirely ruled out, and some heat indices of 116
degrees do indeed exist for that time. However, spatial and
temporal coverage of the 116 degree indices do not match
establish EXCESSIVE HEAT WARNING criteria at this time, so the
idea of the WARNING will be punted to successive shifts to ponder
with newer model guidance.

Finally, the Storm Prediction Center (SPC) places nearly all of
Zapata and Jim Hogg counties, and a sliver of Brooks County, in a
Marginal Risk of severe thunderstorms from around sunrise today
until around sunrise Thursday. Per SPC, this convection will be
due to the combination of a shortwave trough and a stalled
outflow boundary. Indeed, various channels of model guidance show
some convection dropping into the Marginal Risk area either from
the north or west (depending on the model). Mention of convection
out west does indeed exist for around sunset this evening, but
for now, will not include any wind or hail mentions (the main
threats, per the SPC) in the official forecast package.

Thanks to WFO CRP for coordination regarding the short term forecast
hazards.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 257 AM CDT Wed Jun 5 2024

The long term will continue to be dominated by plenty of sun and
moderate to fresh southeast breezes, contributing to persistent
dry and unseasonably hot weather into the weekend. Initially, mid-
level ridging over the Southwest United States will carry over
into the long-term. The intensity of the ridge will weaken a bit
over time, with correspondingly less threat of heat advisory
conditions. Isolated convection may pop up over the Sierra Madre
Oriental Range west of the CWA from time to time.

A mid-level trough will drop out of Canada to move across the
Great Lakes and Northeast United States late in the weekend to
early next week, with a weak front dropping south over the Plains
into North Texas on Sunday. The weak cold front could work its
way into deep South Texas on Monday, stalling out over the area
on Tuesday. The model blend has introduced a slight to low end
chance of rain into the forecast for Monday going into Tuesday,
which is a slight increase from the previous forecast. Given that
another, deeper short-wave trough will dive south over the Plains
on Tuesday, the door could then open for a more unsettled weather
pattern the remainder of next week.

&&

.AVIATION...
(12Z TAFS)
Issued at 532 AM CDT Wed Jun 5 2024

MVFR to VFR will continue to be the rule at the aerodromes,
courtesy of high pressure in the middle layers of the atmosphere.
Moderate to breezy winds today will diminish to lighter levels
tonight and through the overnight hours. Limited cloud cover
during the day will yield to increased cloud cover at night.

&&

.MARINE...
Issued at 257 AM CDT Wed Jun 5 2024

Today through Thursday: Buoy 42020 reported south-southeast winds
around 21 knots gusting to around 27 knots with seas slightly
over 7 feet with a period of 8 seconds at 2:50 CDT/7:50 UTC.
WNAwave10 model guidance was much more representative of what is
currently being experienced at Buoy 42020. Additionally, both
MAVPIL and METPIL model guidance show winds solidly at 20 knots
and above over the Laguna Madre for a good portion of today. As a
result, the Small Craft Advisory for the Laguna Madre and the
Gulf of Mexico waters from 0 to 60 nautical miles offshore has
been extended until around sunset this evening. Afterwards, and
for the remainder of the short term marine forecast period,
generally more moderate winds and seas are anticipated as the
pressure gradient along the Lower Texas Coast begins to ease.
However, Small Craft Should Exercise Caution cannot be ruled out
entirely for tonight, especially due to Gulf of Mexico seas.

Thanks to WFO CRP for coordination regarding the short term marine
hazards.

Thursday night through Sunday night...Generally moderate winds
and seas will prevail through the long term as broad high pressure
resides over the North and West Gulf of Mexico.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             98  82  98  80 /   0  10  10  10
HARLINGEN               99  79  99  77 /  10  10  10  10
MCALLEN                100  82 100  79 /  10  10  20  10
RIO GRANDE CITY        104  80 100  77 /  10  10  10  10
SOUTH PADRE ISLAND      86  84  87  81 /   0  10  10  10
BAYVIEW/PORT ISABEL     96  82  94  79 /   0  10  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from noon today to 8 PM CDT this evening for
     TXZ248>255-351-353>355.

     High Rip Current Risk through this evening for TXZ451-454-455.

GM...Small Craft Advisory until 7 PM CDT this evening for GMZ130-132-
     135-150-155-170-175.

&&

$$

SHORT TERM...66
LONG TERM....54
AVIATION...66