000
FXUS64 KBRO 171849
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
149 PM CDT Wed May 17 2017

.SHORT TERM (Now through Thursday Night): High pressure at the
surface and at the 500 mb level will continue to be the dominant
weather features over Deep South Texas and the Rio Grande Valley
during the short term forecast period. Dry weather will continue
across the BRO CWFA courtesy of this weather pattern. A windy
onshore flow is also likely, with wind speeds just below Wind
Advisory criteria.


.LONG TERM (Friday through Wednesday):Upper level trough centered
over the Four Corners area lifts east northeast towards the Upper
Midwest Friday through the weekend, pushing a boundary south
across Texas. Not much push with this boundary and at this time
expect the front to remain north of the CWA. Ahead of the front
moisture will deepen under a steady onshore flow, with PWATs
approaching and possibly surpassing 2 inches across the northern
and western zones Saturday night into Sunday and into the 1.8 to
2.0 inch range across the mid and upper Valley on Monday. Impulses
in the mean flow move just north of the area combined with
deepening moisture, and boundary in the vicinity could enhance
shower and thunderstorm activity Saturday night into Monday. Best
rain chances remain during the day Sunday, particularly during the
afternoon and evening hours across the northern and western
counties, when daytime heating, combines with a surge of moisture,
and passage of an impulse aloft. Activity diminishes going into
Monday night as the boundary lifts north. Lowered pops slightly to
reflect latest model guidance and thinking. Above normal
temperatures continue Friday and Saturday, with highs well into
the 90s each day across much of the inland areas and approaching
or surpassing the century mark across Zapata and Starr counties.
Increased cloud cover and rain chances will bring cooler
temperatures, closer to normal, for Sunday and Monday.

By Tuesday, forecast becomes more muddled, with models in
disagreement with timing and location of next upper trough and
subsequently the timing of the next boundary pushing across the
region. ECMWF brings the front through Tuesday, the GFS remains on
the slower side, pushing the front though late Wednesday into
Thursday, and the Canadian in between. Timing of feature brings
higher uncertainty into pops and temperatures for this time range.
Given the uncertainty at this point in time and model
disagreement, have opted to go with a slight chance of pops
Tuesday and Wednesday. Blended models for temps Tuesday and
Wednesday.


&&

.MARINE(Now through Thursday Night): Buoy 42020 reported south-
southeast winds around 16 knots gusting to around 18 knots with
seas slightly over 7 feet with a period of 7 seconds at 13 CDT/18
UTC. The interaction between high and low pressure will produce
Small Craft Advisory winds and seas along the Lower Texas Coast
through the forecast period.

Friday through Monday: Hazardous marine conditions expected to
continue through Saturday as moderate to strong southeast winds
prevail. Strong gradient between high pressure over the Gulf of
Mexico and lower pressure across the southern Plains will weaken
going into Saturday afternoon as a cold front moves into central
Texas. Conditions improve by Sunday as winds diminish and shift
to the east and seas subside. Small craft advisories are likely
for all or portions of the lower Texas coastal waters through
Friday night with small craft exercise caution conditions likely
Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  79  91  79  90 /   0   0   0  10
BROWNSVILLE          79  93  79  92 /   0   0   0  10
HARLINGEN            78  94  77  94 /   0   0   0  10
MCALLEN              78  97  79  97 /   0   0   0  10
RIO GRANDE CITY      78 100  78 100 /   0   0   0  10
SOUTH PADRE ISLAND   79  83  79  84 /   0   0   0  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 7 PM CDT this evening for
     GMZ130-132-135.

     Small Craft Advisory until 7 AM CDT Thursday for GMZ150-155-170-
     175.

&&

$$

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