Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 241934

Area Forecast Discussion
National Weather Service Brownsville TX
234 PM CDT Mon Apr 24 2017

.Short Term (Now through Tuesday Night): Latest satellite imagery
shows cirrus streaming across the region this afternoon and after
a cool start to the day temperatures have rebounded quickly into
the 80s. Surface high pressure continues it`s eastward shift
across the Gulf of Mexico this afternoon and winds have returned
to the southeast. Moderate southeasterly flow expected to continue
through much of the period as lower pressure develops across the
southern plains bringing moisture back into the region. A weak dry
line tries to push east across the region by Tuesday afternoon
briefly shifting winds to the west, with dewpoints dropping into
the upper 40s and lower 50s across Starr, Zapata, and Jim Hogg
counties. While RH values drop into the upper teens and lower 20s,
winds behind the dry line will be less than 15 mph, so fire
weather concerns are minimal. Temperatures climb Tuesday with
highs well into the 90s across much of the inland area and to
around the century mark out west, where 850 temps push into the
24C to 26C range. Above normal temperatures continue Tuesday
night, with lows only dropping into the lower to mid 70s.

Long term (Wednesday through Monday): Low level southwest winds
Tuesday night will keep a cap in place through part of the day
Wednesday, even though surface winds will shift to northwest,
courtesy of the dryline making a rare appearance in deep South
Texas and the RGV. Surface heating will be promoted in the absence
of mixing until later in the day when temperatures get high
enough for parcels to break the cap and enhance mixing. Normal
high temps for Wednesday are in the mid to upper 80s, with the
record highs at BRO/HRL/MFE checking in at 98/99/107 degrees,
respectively. Though 107 degrees in MFE might be a challenge, the
records at BRO and HRL will be within reach. Due to the influx of
drier air, apparent temperatures will not be greatly enhanced. It
looks like the true front will push into the CWA Wednesday night
with a wind shift to north and northeast, but without much other
fanfare. Temperatures on Thursday will come down a skosh, perhaps
staying under the century mark for most spots. High pressure from
the previous day will shift quickly east, with winds veering to

The theme of hot weather will be justified for most of the long
term, exacerbated by an occasional period of increased wind. One of
those periods will develop on Friday for most of the CWA excluding
the Upper Valley. Pressure falls over West Texas down through the
front range of the Sierra Madres will be induced partially by mid
level troughing over the Southwest United States and partially by
heat effects. Look for breezy to windy conditions then, with mdt
southeast winds continuing on Saturday. High temps will inch upward
again on Friday and Saturday, with a few century marks or above west
of the coastal counties, basically inland. A front will push into
the CWA on Sunday, bringing a shift to breezy northwest winds during
the day. It`s possible that isolated tail end showers could develop,
more so across the northern counties, but by later in the day much
drier air will move in, putting the kibosh on any rain chances. The
forecast then teases us with halcyon conditions on Monday, with high
temperatures in the 80s, near normal.


Now through Tuesday Night: Winds remain light to moderate across
the Laguna Madre and Gulf waters this afternoon, with Buoy 42020
reporting seas of 2 feet. Southeasterly flow strengthens later
this evening and tonight as lower pressure developing and moving
across the southern Plains interacts with the high over the Gulf.
Small craft exercise caution conditions are likely for the lower
Texas coastal waters tonight, with marginal Small Craft Advisory
conditions possible over the Gulf waters late tonight. Advisories
are likely for the Laguna Madre and near and offshore Gulf waters
Tuesday and the Gulf waters Tuesday night.

Wednesday through Saturday: Strong south winds early Wednesday
will diminish during the day and into Wednesday night, becoming
moderate northeast to east on Thursday with the arrival of a
front into South and deep South Texas. However, southeast winds
will ramp up again Thursday night as the front retreats, high
pressure slides east, and the gradient tightens. Small craft
should exercise caution conditions Thursday night will turn into
low end small craft advisory conditions Friday and Saturday.


.Fire Weather: Very low relative humidity values will develop
Wednesday afternoon as dry air surges into the area from the
northwest. RH values in the teens will be possible west of US 77/I-
69E Wednesday afternoon. Winds at 20 feet will be northwest 10 to 15
mph with drying fuels. The sudden onset of high temperatures for the
day and the decrease in soil moisture may suggest a flash drought.
These conditions may be enough to produce enhanced wildfire growth
and spread and will be monitored. Another opportunity for fire
weather caution will be next Sunday when a front moves through. A
shift to breezy northwest winds, coupled with drier air and lower RH
values, with drier fuels to promote enhanced wildfire growth and
spread potential.


BAYVIEW/PORT ISABEL  71  89  76  95 /   0   0   0   0
BROWNSVILLE          71  89  76  98 /   0   0   0   0
HARLINGEN            70  93  74 100 /   0   0   0   0
MCALLEN              70  97  74 103 /   0   0   0   0
RIO GRANDE CITY      68 100  72 102 /   0   0   0   0
SOUTH PADRE ISLAND   73  83  76  88 /   0   0   0   0




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