Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Brownsville/Rio Grande Valley, TX (BRO)

                            
000
FXUS64 KBRO 181759 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1259 PM CDT Wed Sep 18 2019

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

&&

.AVIATION...Vsbl satl imagery shows high level cirrus left over
from the remnants of Imelda over SE TX moving over the RGV.
Meanwhile, daytime heating is generating some spotty CU fields
over southern TX. KBRO radar also indicates some patchy marine
showers firing up over the western Gulf watersjust offshore of the
RGV. SW flow aloft indicated by the last several soundings from
BRO show that some drier air has started filtering into the region
resulting in generally lower PWAT's and CAPE values. The ECMWF/NAM
and GFS model guidance all show a generally dry pattern 
continuing for the region as 500 mb ridging steadily strengthens.
So will go with VFR TAF's for the 18Z issuance for all three local
airports. 

&&

.PREV DISCUSSION... /issued 628 AM CDT Wed Sep 18 2019/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...Light south winds with a few passing high clouds
prevail across deep south Texas this morning. Expect VFR 
conditions for the next 24 hours as subsidence continues over the 
region. Light south winds this morning will increase and become 
moderate this afternoon. 

PREV DISCUSSION... /issued 444 AM CDT Wed Sep 18 2019/ 

SHORT TERM (Now through Thursday): Mid level ridging will provide 
subsidence over deep south Texas through the period. Broad surface 
high pressure across the Gulf of Mexico is expected to maintain 
south to southeast winds through Thursday. The onshore flow will 
allow low level moisture to steadily increase across the area.
High temperatures Today and Thursday are expected to range from the 
low to mid 90s near the coast to the upper 90s to around 100 degrees 
far inland. The combination of higher temperatures and dewpoints 
should support heat index values across portions of the the CWA this 
afternoon and Thursday afternoon to reach 105 to 109 degrees. Low 
temperatures tonight will be in the mid to upper 70s, except for the 
lower 80s near the coast. Rain-free conditions are expected Today 
and Tonight period due to shallow moisture. However, a few streamer 
showers will be possible after midnight on the Gulf waters. Isolated 
seabreeze showers and thunderstorms can be expected on Thursday near 
the coast.

LONG TERM (Thursday Night through Tuesday): Persistent 500 mb 
high pressure positioned over the Gulf Coast will aid in bringing
deeper tropical moisture into Deep South Texas and the Rio Grande
Valley, with precipitable water values near 2 inches. As a result,
isolated convection will be possible nearly daily within the BRO
CWFA. Near to slightly above normal temperatures are also expected
due to the relatively limited rain chances and cloud cover. 

MARINE (Now through Thursday): Broad high pressure across the Gulf 
will support moderate winds and seas through the period. Small craft 
should exercise caution on the Laguna Madre Today and Thursday 
and at times on the Gulf waters.

Thursday Night through Tuesday: Swell approaching the Lower Texas
Coast may produce Small Craft Exercise Caution for a portion of
the Gulf of Mexico waters from Friday night through Sunday. For
the remainder of the forecast period, generally moderate winds and
seas are anticipated. 

&&

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

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

Short Term/Aviation...60
Long Term...54/67
Graphicast/Upper Air...67