980 
FXUS64 KBRO 081730 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1230 PM CDT Fri Oct 8 2021

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...The aviation conditions are about as good as possible
across the RGV as 500 mb ridging and very low CAPE/PWAT values
maintain the VFR conditions across the RGV this afternoon. The
surface dewpoints may start rebounding tonight and Sat increasing
the potential for some patchy fog across the northern Ranchlands
tonight. But do not expect any fog formation to cause serious
disruptions to the RGV vsbys early tomorrow morning. So VFR
conditions will prevail over the upcoming 24 hours for the RGV. 

&&

.PREV DISCUSSION... /issued 626 AM CDT Fri Oct 8 2021/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...VFR conditions are expected to generally prevail
through the TAF period. There may be a few areas with shallow
patchy fog over the next hour or two. Patchy shallow fog may
develop again near daybreak Saturday morning. Light E to ESE winds
are expected during the afternoon with light and variable to near
calm winds overnight. 

PREV DISCUSSION... /issued 252 AM CDT Fri Oct 8 2021/ 

SHORT TERM (Now through Saturday): High pressure continues to build 
across Deep South Texas into the weekend, as a 500mb trough digs 
into the Rockies and another works through the Great Lakes. 
Generally comfortable conditions persist locally into Saturday, with 
RH values between 30 to 40 percent expected both afternoons. Highs 
remain near normal with near to below normal lows due to mostly 
clear skies and radiational cooling. Heat Indices top off in the low 
to mid 90s Friday and mid to upper 90s on Saturday. Patchy shallow 
fog is possible this morning and slightly more likely Saturday 
morning.

LONG TERM (Saturday Night through Thursday): Mid level ridging 
initially over deep south Texas, will weaken and slide eastward 
Sunday into Sunday night as a sharp 500 mb trough digs over the Four 
Corners and into the southern High Plains. As a result, surface low 
pressure will develop and deepen across the Texas Panhandle into the 
central Plains allowing the pressure gradient to strengthen. 
Moderate to breezy winds are expected Sunday through midweek, 
especially near the coast. The steady southeast to southerly flow 
will bring back low level moisture but will not be enough to 
significantly elevate rain chances through Tuesday night. Above 
normal temperatures will occur across the region this weekend and 
into early next week. 

Another mid level trough will swing through the Plains around mid 
week. The associated cold front is expected to move into Texas on 
Wednesday. The combination of moisture pooling along and ahead of 
the front and mid to upper level moisture from the Pacific will 
support increasing rain chances Wednesday into Thursday. Near to 
slightly below normal temperatures are expected late in the period.

MARINE (Now through Saturday): High pressure and light easterly 
or southeasterly onshore flow will continue favorable marine 
conditions into the beginning of the weekend. Mariners will find a
light chop on the bay during the afternoon hours, with Gulf seas 
of 1 to 2 feet. 

Saturday Night through Tuesday Night...Light to moderate 
onshore flow and low to moderate seas initially with broad high 
pressure across the Gulf. South to southeast winds will increase 
and building seas will develop Sunday into early next week as the 
pressure gradient strengthens along the lower Texas coast. Small 
craft should exercise caution conditions will develop at times 
from Sunday through Tuesday with low end small craft advisory 
conditions possible by Tuesday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  70  88  76  92 /   0   0   0   0 
BROWNSVILLE          70  92  78  95 /   0   0   0   0 
HARLINGEN            67  91  75  95 /   0   0   0   0 
MCALLEN              67  94  75  98 /   0   0   0   0 
RIO GRANDE CITY      65  98  74 103 /   0   0   0   0 
SOUTH PADRE ISLAND   78  84  80  86 /   0   0   0  10 

&&

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

$$

This product is also available on the web at:
https://weather.gov/rgv

Short Term/Aviation...60-Speece
Long Term...54-BHM
IDSS...69-Farris