Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 210600 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
100 AM CDT Wed Jun 21 2017

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

&&

.AVIATION...Light and variable winds overnight will become gusty
NW to NE through the period as Tropical Storm Cindy moves across
the Northwestern Gulf waters. Dry weather and VFR conditions will
continue.

&&

.PREV DISCUSSION... /issued 629 PM CDT Tue Jun 20 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...VFR is expected through the next 24 hours, with winds
out of the northwest to northeast due to Tropical Storm Cindy
affecting the central Gulf of Mexico.

PREV DISCUSSION... /issued 242 PM CDT Tue Jun 20 2017/

SHORT TERM (Tonight through Wednesday Night): Coastal and Marine
impacts will be of the main concern from newly formed Tropical
Storm Cindy, located over the North Central Gulf of Mexico. Inland
areas will see nothing more then more heat and a fire weather
threat. As for the coastal hazards large swell being generated by
TS Cindy will be directed toward the Texas coast the next 24-36
hours...See marine section below for heights. As the higher swell
approaches the coast it will result in rough high surf with
pounding breakers, a high risk of rip currents and the potential
for coastal flooding. Astronomical high tide occurs around 330 am
so the best chance of coastal flooding is late tonight and around
sunrise, however with the high swell conditions anticipated to
peak Wednesday afternoon overwash to the dunes is possible along
any location from Boca Chica beach, South Padre Island to Kenedy
county.

Model consensus and NHC track is for TS Cindy to make headway for
the Upper Texas/SW Louisiana coast making landfall sometime late
Wednesday night/sunrise Thursday.  With our CWA remain on the west
dry subsidence  side of the storm`s circulation we can expect more
of the same hot dry weather.  Precipitable water values from this
morning`s sounding already were below seasonal normals at 1.5 inches.
GFS and NAM forecast for the PWATS to drop dramatically between 0.75-
1 inch which is at or below the 10 percentile or normal or very
close to record territory.  This dry air coupled with
compressed/subsident air will result in temperatures soaring well
above the century mark for many locations along and west of I-69E.
NAM is the most aggressive with Max Temps showing Brownsville
reaching 104 degrees. Records highs will be jeopardy at all RGV
climate stations. Overnight, conditions tonight and Wednesday will
be sultry to say the least with temperatures slow to drop off but
bottoming out near seasonal averages with clear skies and a slow
recovery of dew points overnight.

LONG TERM (Thursday through Tuesday): With Tropical Storm Cindy
inland across southeast Texas/southwest Louisiana Thursday...southwest
TX will be on the subsident side of the tropical low and low to
mid level moisture will be limited across the Rio Grande Valley
and northern ranchlands through Thursday and Friday. Low to mid
level moisture will increase across south TX through the weekend
as an inverted 500mb trough develops across the lower TX coast
between the 500mb ridge across the southwest United States and the
500mb ridge across Florida and eastern Gulf of Mexico. This
should provide at least a slight chance to chance of showers and
isolated thunderstorms through the weekend into early next week as
a weak cold front makes its way into south TX Sunday and Monday
allowing moisture to pool across the CWA. With the increase in
cloud cover and rain chances...temperatures will not be as hot
Saturday through Tuesday as they will be Thursday and Friday.

Fire weather...Dry northwest to north flow around the western
periphery of Tropical Storm Cindy coupled with subsidence of very
dry air in the mid layer will allow for dew points to fall well
below normal Wednesday. Extremely high temperatures, 100-108
degrees, to combine with the low dew points crashing relative
humidity between 20-30 percent along and west of I-69C. Deep Mixing
of the boundary layer will allow for moderate wind to mix to the
surface in the afternoon with winds between 15-20 mph. This should
allow for elevated fire conditions but keep them just shy of Red
Flag conditions. A Range Fire discussion is likely to be issued
tomorrow for the elevated threat.

MARINE (Tonight through Wednesday night): At 2 pm CDT, Buoy 42020
was reporting waves around 4 feet and a 7 second East swell at 2
feet with north wind at around 15 knots.  The 42002 buoy (approx.
200nm East of Brownsville) was reporting seas near 11 feet and a 10
second swell at 8 feet. This higher swell is expected to impact the
Lower Texas Coastal waters tonight and Wednesday as newly formed
Tropical Storm Cindy continues to move slowly northwest the next
24 to 36 hours. Small craft advisories go into effect for the Gulf
waters at 7 pm and will likely continue through Wednesday night.
Winds to increase but tropical storm force winds are not
anticipated with Cindy having a rather small center and with the
strongest winds remaining on the northern and east side of the
tropical storm well removed from the Lower Texas Coastal waters.
Swell from the east become more northeast to north Wednesday night
into Thursday with a steadily lowering at that time. An isolated
shower or thunderstorm is possible but not anticipating any
squalls with the storm passing well north of the region.

Thursday through Sunday...Light to moderate west to southwest
winds will prevail across the coastal waters Thursday with
Tropical Storm Cindy inland across southeast Texas/southwest
Louisiana. Winds are expected to back to the south Thurs night and
increase as the pressure gradient increases across the western
Gulf of Mexico in the wake of Cindy. Moderate to strong southerly
winds should prevail across the lower TX coast Friday. The
pressure gradient is progged to weaken Saturday and winds are
expected to decrease and back to the east as a weak frontal
boundary moves into central TX. Light to moderate east to
southeast winds should prevail across the coastal waters through
the weekend.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk from 5 AM CDT early this morning through
     this evening for TXZ251-256-257.

     High Surf Advisory from 5 AM early this morning to 7 PM CDT this
     evening for TXZ251-256-257.

GM...Small Craft Advisory until 7 PM CDT this evening for GMZ150-155-
     170-175.

&&

$$

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