Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 222045
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
245 PM CST Wed Nov 22 2017

...Chamber of Commerce Weather For the Holiday Weekend...

.SHORT TERM (Tonight through Thursday Night): A cold front continues
to push farther east away from Deep South Texas and the Rio Grande
Valley. A few persistent showers continue to develop over the
adjacent Gulf of Mexico waters, but these should end by around
sunset this evening as drier air flows into the region from the
northwest. Absolutely quiet weather is anticipated tonight and
through Thanksgiving Night as the center of surface high pressure
eases across the Lone Star State. Near normal daytime high but below
normal overnight low temperatures courtesy of a persistent offshore
flow are expected.

.LONG TERM (Friday through Wednesday): A splendiferous start to
the weekend portion of the Thanksgiving break, with "Black" Friday
loaded with *Blue* sky, green grass, and easy flowing surf.
Following this perfect day will be a fair weather weekend with a
warming trend Saturday as subtropical 500 mb ridge centered over
northwest Mexico and the southwest U.S. begins to edge back toward
south and west Texas. By Sunday, the GFS and ECMWF diverge
slightly, with the ECMWF taking a piece of energy and diving it
down the backside of the eastern U.S. 500 mb trough Saturday
night/Sunday, which would temporarily reinforce the surface ridge
over north and east Texas and back winds more to the north and
northeast. GFS/Canadian GGEM push the backside energy farther east
into the central/eastern Gulf, leaving the 500 mb ridge to
continue nudging east. This is a recent development with the ECMWF
so for now will generally disregard except to nudge winds briefly
to the east- northeast, still a light speeds, early Sunday.

The core of the subtropical ridge shifts east Monday and Tuesday
to south Texas, which will maintain the warm days but also help
bring a more pronounced southerly flow which will bring overnight
temperatures (and dewpoints for that matter) back up a few
notches. Model departures begin at the end of the period, with the
GFS still fairly consistent on a midday Wednesday frontal surge
while the ECMWF has changed a bit, digging a stronger 500 mb
trough into the southern Plains while strengthening the
subtropical ridge over the eastern and central Gulf. While the GFS
has been handling November`s fronts better in the Days 5-7 range
this year, uncertainty and lack of any strong cold air push keep
me from nudging the current seasonable forecast (mid to upper 70s
Valley, around 70 ranchlands) for next Wednesday very far. Have
left the low chances of precipitation which would be elevated
convection behind the surface boundary at this point, as well as
considerable clouds.

Until then, for the sensible weather - maintained mainly clear
skies through Tuesday with light/variable winds Friday (with a
minimal sea breeze due to nearly similar land/sea temperatures)
then a light southeast flow, in general, through the weekend. Some
increase in wind Monday and perhaps into Tuesday as low pressure
develops and moves through the southern Plains. Model blends for
temperatures given full sunshine and increasing atmospheric warmth
seemed too low for Saturday, so leaned toward the warmer GFS
deterministic. Sunday is a bit tougher especially if winds do back
to the northeast, which would drop highs about 5 degrees or so.
Split the difference for now, with lower 80s (still around 6
degree above average) rounding out a great weekend to show guests
the flora and fauna of the Valley - and others an easy travel
period to and from the region.

&&

.MARINE: Tonight through Thursday Night:  Adverse marine
conditions are continuing along the Lower Texas Coast in the wake
of the cold front which swept through earlier today. Diminishing
winds and subsiding seas are expected to occur during the next 18
hours, allowing the Gale Warning and Small Craft Advisory for
Winds currently in effect to no longer be needed by around sunrise
Thursday morning. Marine conditions will continue to improve
tomorrow and tomorrow night as surface high pressure builds in
from the northwest. Despite the improvement, Small Craft Exercise
Caution may be needed for a portion of the Gulf of Mexico waters
during the daylight hours of Thursday due to seas.

Friday through Monday: In a word? Perfect! Hard to beat light
winds and slight seas for the holiday weekend on the Gulf, with
just a slight pickup in winds beginning Monday. Laguna Madre
mornings should be clear, calm, with glassy water. Enjoy!

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  50  69  47  74 /   0   0   0   0
BROWNSVILLE          49  73  50  76 /   0   0   0   0
HARLINGEN            46  72  46  76 /   0   0   0   0
MCALLEN              47  74  48  78 /   0   0   0   0
RIO GRANDE CITY      43  75  45  79 /   0   0   0   0
SOUTH PADRE ISLAND   57  68  57  73 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 6 PM CST this evening for
     GMZ130-132-135.

     Small Craft Advisory until 6 AM CST Thursday for GMZ150-155-170-
     175.

     Gale Warning ending at 3 PM CST this afternoon for
     GMZ150-155-170- 175.

&&

$$

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

Short Term...66/JGT
Long Term...52/BSG
Marine...66/52
Graphics/Short Term Forecast...Brady/Hallman



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