086 
FXUS64 KBRO 232330 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
630 PM CDT Fri Sep 23 2022

...New AVIATION...

.SHORT TERM...
(Tonight through Saturday night)
Issued at 236 PM CDT Fri Sep 23 2022

Mid-level ridging centered over Texas will provide large scale 
subsidence across much of Texas. However, the northern tip of a 
500mb inverted trough, also evident at 700mb, moving from east to 
west over the Southwest Gulf of Mexico will cut under the ridge as 
it heads toward the Northeast Mexican Coast. The trough, along with 
enhanced moisture over the Gulf, will support an increase in local 
convection during the short term. This may result in a slightly 
enhanced sea breeze on Saturday.

In essence, deeper moisture will surge into the region tonight and 
Saturday with PWATs between 1.5 and up to 2.0 inches in the more 
aggressive models. Isolated to scattered showers and thunderstorms 
will develop across the Gulf waters tonight and try to push inland 
on Saturday, but there will still be a mix of clouds and sun for the 
day. Forecast QPF amounts are looking rather unimpressive, with some 
coastal areas of Kenedy and Willacy Counties mustering a couple 
tenths of an inch of rain accumulation in any given six hours, but 
most areas will see less. At the surface, broad high pressure across 
the Gulf of Mexico will maintain light to moderate east to southeast 
winds.

Temperatures overall will trend slightly above normal in the short 
term with a mix of clouds and sun. High temps on Saturday will range 
from the 80s at the beaches, the lower 90s near the coast, and the 
mid to upper 90s farther inland. Overnight low temps will generally 
decrease into the 70s, except around 80 at the beaches. Patchy 
shallow ground fog will be possible around daybreak Saturday, 
especially inland and across the Northern Ranchlands. In the short 
term, rip current risk will remain low, and there will be no heat or 
fire weather concerns.

&&

.LONG TERM...
(Sunday through next Friday)
Issued at 236 PM CDT Fri Sep 23 2022

A Weakening inverted trough over northeast Mexico and limited 
moisture values with light east-south flow to support a continued 
chance of showers and thunderstorms Sunday. This weakness aloft 
pretty much dissipates Monday leaving us to look upstream for our 
next potential for rainfall.  Strong mid-upper trough moving into 
the Great Lakes and Ohio Valley early next week will send the first 
cold front of Fall season to south Texas, albeit not very strong.  A 
pre-frontal low pressure trough in advance of the front Monday and 
the cold front itself Tuesday to trigger isolated to scattered 
showers and thunderstorms as moisture charts show a deepening of 
moisture, especially near the coast.  Much drier air filters into 
the region in wake of the front cutting off our chances for rain the 
latter half of next week. 

As for the Tropical Depression 9, the upper trough to our north and 
the cold front passage is likely to protect the western Gulf and the 
RGV from any significant direct impacts.  Minor coastal impacts of 
coastal flooding coinciding with astronomical high tides next 
Tuesday through Thursday and some higher swells over the Gulf waters 
is all that we anticipate from this system.  For sensible weather, 
the circulation of the tropical cyclone looks to combine with the 
surface high building in behind the front to enhance the dry air 
intrusion as northeast flow strengthens.  Models are suggesting dew 
points dipping into the 40s and 50s by mid-week which will make 
these humid days as of late a thing of the past. Temperatures and 
humidity will be elevated Sunday through Monday with lows in the 70s 
and highs in the 90s. Heat indices still pushing the lower 100s.  In 
wake of the front high temperatures are not expected to be that much 
cooler with upper 80s to lower 90s but as mentioned daytime humidity 
will be much lower in the 20-40 percent range Wednesday and 
Thursday.  Low temperatures will be the most noticeable as dew 
points fall minimums are shown to bottom out in the low to mid 60s, 
but would not be surprised to see some upper 50s inland over the 
open ranchlands Thursday and and Friday mornings. 

&&

.AVIATION...
(00Z TAFS)
Issued at 621 PM CDT Fri Sep 23 2022

VFR conditions are expected to persist through the next 24 hours.
Moderate east-southeasterly winds will become light and variable
overnight before strengthening to become moderate again by midday
Saturday. Isolated to scattered showers and thunderstorms will be
possible on Saturday, especially along the sea breeze, but due to
the limited coverage and low confidence in the timing, have left 
out any mention of rain or thunder in the TAFs for now. 

&&

.MARINE...
Issued at 236 PM CDT Fri Sep 23 2022

Now through Saturday Night...Light to moderate onshore winds and low 
to moderate seas will prevail through the short term. Swell period 
will center around 5 seconds. Shower and thunderstorm chances will 
trend higher as tropical moisture returns and the northern tip of an 
inverted trough aloft moves overhead.

Sunday through Wednesday: Fair marine conditions are forecast 
through at least Monday, outside of any isolated thunderstorms. Weak 
high pressure over the northern Gulf of Mexico supports a slack 
pressure gradient with a continuation of light winds and slight 
seas.  

An approaching cold front Monday night with a weak passage Tuesday 
morning turns the winds northeast at moderate speeds. Tropical 
Depression 9, currently over the Central Caribbean, is forecast to 
enter the Southeastern Gulf early Tuesday as a strengthening 
Tropical Cyclone and is likely to track over the Eastern Gulf of 
Mexico Tuesday and Wednesday. Although no direct impacts are 
expected along the lower Texas coast, a moderate to higher swell 
train, potentially as high as 7 feet or better, may move into the
coastal waters and Tuesday and Wednesday and possibly lingering 
Thursday. Northeast winds may also be enhanced later Tuesday and 
Wednesday and looks to reach the higher end of exercise caution 
levels with some gusts exceeding 20 knots. 

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             76  93  77  93 /  20  30  20  30 
HARLINGEN               73  92  74  92 /  10  30  10  30 
MCALLEN                 74  95  76  95 /   0  20  10  40 
RIO GRANDE CITY         72  96  74  96 /   0  10   0  20 
SOUTH PADRE ISLAND      80  88  80  87 /  30  20  20  20 
BAYVIEW/PORT ISABEL     76  91  76  90 /  30  20  20  20 

&&

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

$$

SHORT TERM...54-BHM
LONG TERM....59-GB
AVIATION...69-Farris