Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 241647 AAB
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1147 AM CDT WED AUG 24 2016
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...VFR conditions are currently in place at the TAF
sites, with mostly sunny skies and moderate, gusty southeast
winds. Satellite shows the beginnings of CU streets over the
coastal counties. An H5 ridge remains over the Southeast U.S. and
the North Gulf, with broad high pressure at the surface. The
pattern will remain in place for the next 24 hours. Will see
continued VFR with light winds and mostly clear to clear skies
tonight, becoming mostly sunny to partly cloudy on Thursday with
moderate east southeast winds as high pressure retreats to the
northeast. Thursday morning coastal showers may develop, with an
afternoon sea breeze slightly more probable.
.PREV DISCUSSION... /issued 632 AM CDT WED AUG 24 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...Mostly clear skies and light southeast winds prevail
across deep south Texas this morning. VFR conditions expected for
the next 24 hours as a mid level ridge continues overhead and
provides subsidence across deep south Texas. Light southeast winds
this morning will become moderate and gusty later this morning.
Winds will gradually diminish to around 10 knots by late this
PREV DISCUSSION... /issued 431 AM CDT WED AUG 24 2016/
SHORT TERM (Today through Thursday): Brownsville radar shows a few
streamer showers across the Gulf waters this morning. This activity
is moving to the northwest and should begin to diminish after
sunrise. Water vapor imagery continues to indicate an east to west
elongated mid level ridge over the northern Gulf of Mexico this
morning. This deep layer ridge will continue over the region through
the forecast period. This will result in hot and dry conditions for
today. Moderate and gusty southeast winds can be expected today due
to the tightening of the pressure gradient. Light winds and
increasing low level moisture should support isolated seabreeze
convection on Thursday. High temperatures today and Thursday will be
slightly above normal with heat index readings generally between 103
to 108 degrees each afternoon. Light winds are expected tonight with
low temperatures generally in the upper 70s.
LONG TERM (Thursday Night through Tuesday): The western edge of
the 500 mb ridge axis will remain in place over the RGV on
Thursday night and Friday. The ridge axis will then start shifting
north and east away from the RGV this weekend as broad troffing
prevails over the western and central states. As the ridge shifts
farther away from the RGV...broad 500 mb troffing will then
gain control over the region through early next week. As the troffing
builds over the region two areas of deeper layer moisture will
start advecting into the region. One from central Mexico moving
north and east. The other moving west towards Texas from the Gulf
of Mexico. The combination of the better moisture levels...the
weakening of the 500 mb ridge and the better potential for
diurnal heating effects will increase the convective potential a
bit through next Tuesday.
Tropics...Now on to the subject that is on everybody`s minds. IR
satl imagery shows a broad area of low pressure east of the
Lesser Antilles moving west northwest. NHC gives this tropical
feature a 70% chance of becoming a tropical cyclone over the next
5 days as it moves towards the Florida peninsula. The GFS and
ECMWF differ greatly for the longer range progress for this
tropical feature as it gets closer to Florida. The ECMWF keeps
this system moving on a general west northwest direction with the
system located roughly over the north central Gulf of Mex by late
Monday/early Tuesday. The GFS has this system moving more slowly
and with a more eastward track eventually recurving back out into
the western Atlantic later next week. So given the large
discrepancy between the two longer range model solutions...
residents of the lower Texas coastline should continue to monitor
the progress of this system over the next several days. Please
refer to the latest statements and outlooks from NHC.
The GFS and ECMWF temp and pop guidance for the RGV are in
reasonable agreement into this coming weekend and then start to
differ more for next week with the ECMWF having a warmer and drier
solution versus the GFS. This disagreement in the temps and pops
is likely due to the more westward placement of the above
mentioned tropical system near the Lesser Antilles moving into
the Gulf of Mexico next week. So will opt for a general model
blend for pops and temps through Day 7. Overall confidence in the
forecast temps and pops through Day 7 is only average due to
these model differences.
MARINE (Now through Thursday): Buoy 42020 reported south-
southeast winds around 12 knots gusting to near 14 knots with seas
around 2.3 feet with a period of 6 seconds at 300 AM CDT/08 UTC.
Surface high pressure across the Gulf of Mexico will maintain
generally light to occasionally moderate southeast winds and low
to moderate seas along the lower Texas coast through Thursday.
Isolated streamer showers will be possible, mainly overnight.
Thursday night through Sunday night...The surface ridging will
weaken over the Gulf of Mexico as the flow pattern comes more
under the influence of the tropical system approaching the Florida
area this weekend. This will result in a gradually shift of the
surface winds along the lower Texas coastline to a more east to
northeasterly direction later in the forecast period. Since the
PGF will remain fairly weak the winds and seas for the bay and
gulf waters will remain pretty benign. No SCA conditions expected
through Sunday night.
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