Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 281125 AAA

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
625 AM CDT Wed Jun 28 2017

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

.AVIATION...Showers are affecting BRO at this time and this has
been built into the latest TAF issuance. Otherwise, the previous
suite of TAFs remains largely unchanged, with surface and mid-
level low pressure producing another round of convection this
afternoon. VFR will prevail today with a possible slip into MVFR
tonight depending on cloud coverage, which could be overstated.

.PREV DISCUSSION... /issued 318 AM CDT Wed Jun 28 2017/

SHORT TERM (Now through Thursday): Weak surface low pressure
over the western Gulf of Mexico will combine with 500 mb troughing
over the northwest Gulf of Mexico and deep tropical moisture
within the BRO CWFA to produce mainly scattered showers and
thunderstorms for Deep South Texas and the Rio Grande Valley
today. Convection will wane tonight with the loss of daytime
heating, but streamer activity will affect the adjacent coastal
waters and inland areas along and east of the Interstate 69C
corridor. Although the aforementioned 500 mb trough will persist
on Thursday, the convection will decrease to more isolated levels
as drier air begins to work into the region and precipitable water
values fall to below two inches. Temperatures are expected to
warm from near normal levels today to above normal levels on
Thursday as the available atmospheric moisture begins to decrease.

LONG TERM (Thursday Night through Tuesday): A weakness in the
500mb ridge across the Texas coast will continue Thursday into
Friday providing at least a slight chance of showers and
thunderstorms across the coastal sections of the CWA through the
rest of the week. The 500mb ridge across the eastern Gulf of
Mexico is expected to build westward into south TX Saturday while
the 500mb ridge across the southwest United States and northern
Mexico provides subsidence across southwest TX through the
weekend. Low to mid level moisture will be limited across most of
the state Sunday into early next week. Rain chances will be
limited through the rest of the forecast period as the 500mb
subtropical ridge across the southwest U.S. shifts eastward

MARINE (Now through Thursday): Buoy 42020 reported southeast winds
around 6 knots gusting to around 8 knots with seas slightly over 2.5
feet with a period of 6 seconds at 02 CDT/07 UTC. Weak low pressure
over the western Gulf of Mexico will produce light to moderate winds
and low to moderate seas along the Lower Texas Coast today and
tonight. As the low pressure system dissipates and high pressure
over the entire Gulf of Mexico begins to interact with low pressure
over the Central Plains tomorrow, winds will increase, and a Small
Craft Exercise Caution may be needed for portions or all of the
Lower Texas coastal waters at that time, especially the Laguna

Thursday night through Sunday...Moderate to strong southeast winds
will prevail across the coastal waters Thurs night into Friday
with surface low pressure across west Texas and high pressure
across the Gulf of Mexico. The pressure gradient will remain
strong across the lower TX coast Saturday before weakening on
Sunday. Small craft advisories may be needed for portions of the
coastal waters Thurs night through Saturday.



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