Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 231147 AAA

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
647 AM CDT Sun Jul 23 2017

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


.AVIATION...VFR conditions are expected to prevail through the
next 24 hours with strong southeast winds being the main aviation
concern. With daytime heating later this morning, low level jet
winds will mix to the surface through Sunday afternoon with winds
gusting to 30 knots at times. Winds will diminish after sunset but
remain moderate through the night as a low level jet continues
between 2000-5000 feet AGL.


.PREV DISCUSSION... /issued 425 AM CDT Sun Jul 23 2017/

SHORT TERM (Now through Monday): A weak mid-level low will
continue to fill as it moves into the upper Texas coast underneath
a broad ridge of high pressure located over the Central US. Most
of the moisture and instability with the disturbance will be well
to our north with mainly only some upper-level cirrus clouds
moving overhead of Deep South Texas this weekend. The main story
will be the hot and breezy conditions as surface high pressure
over the northern Gulf of Mexico maintains strong southeast flow.
Despite some cirrus cloud cover expected, temperatures will still
be able to climb into the upper 90s to above 100F for much of the
area. Daytime mixing should keep us under Heat Advisory criteria,
but Heat Indices will range from 105-110F again for much of the
Rio Grande Valley. Wind gusts of 30 to 35 mph will also be common
as low level jet winds mix down to the surface Sunday afternoon
and continue through just after sunset. Monday, similar conditions
will continue with hot temperatures and breezy winds during the
afternoon. Rain chances are very low through the short term as
model guidance keeps RH values generally from 30 to 50% below

LONG TERM (Monday Night through Saturday): 500mb subtropical
ridge across the south-central United States Monday and Tuesday is
progged to shift slightly westward Wednesday. Low to mid level
moisture is expected to increase slightly across the CWA Tuesday
and this will provide at least a slight chance of showers and
thunderstorms...mainly across the coastal sections...Tuesday and
Wednesday. A 500mb shortwave trough developing across the
southeast U.S. Thursday should amplify the upper level ridge
across the southwest and south-central U.S. and subsidence will
increase across south Texas through the rest of the week. Rain
chances will diminish Thursday into Friday with not much in the
way of rain chances Saturday. Temperatures will remain near normal
to above normal Mon night through Saturday.

MARINE (Now through Monday): Strong southeast flow will continue
through the day Sunday with a tight pressure gradient resulting from
a surface high over the northern Gulf of Mexico and low pressure
in the Central Plains. Winds may reach or exceed 20 kts over the
Laguna and nearshore Gulf waters, so have issued a Small Craft
Advisory for winds from 18Z to 01Z. Monday, winds should be
slightly lower, but Small Craft Exercise Caution conditions for
winds will be likely.

Monday night through Thursday...Moderate to strong southeast winds
will prevail across the coastal waters Mon night as surface
high pressure across the eastern Gulf of Mexico and surface low
pressure across northern Mexico provides a strong pressure
gradient across the lower Texas coast. The pressure gradient
will weaken slightly across the western Gulf of Mexico on Tuesday.
Moderate southeast winds will prevail across the lower TX coast
on Tuesday. The pressure gradient will remain relatively weak
across the western Gulf of Mexico Wednesday and Thursday. Light to
moderate southeast winds should prevail across the coastal waters
Wednesday and Thursday.


GM...Small Craft Advisory for winds from 1 PM this afternoon to 8 PM
     CDT this evening for GMZ130-132-135-150-155.



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