Area Forecast Discussion
Issued by NWS Brownsville, TX

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603
FXUS64 KBRO 191954
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
254 PM CDT Sun Mar 19 2017

.SHORT TERM (Now through Monday Night): High pressure, both
surface and aloft, will continue to dominate the weather through
the short- term. MSLP at BRO currently reading 1023mb even near
the diurnal minimum. Temps have risen into the 80s F across the
CWA, with a couple upper 80s noted in the McAllen vicinity. Fair
weather Cu hanging on across much of the area as well. Winds are
generally SSE at 10-20mph.

The only change of note during the next 36 hours is that a slug of
even drier air beneath the upper high will move into the eastern
half of the CWA overnight.  Combined with winds staying up in the 8-
10mph range, fog formation should be mainly precluded in the mid-
Lower Valley.  SCT low clouds may form near the base of an inversion
progged to form up at around 1,500-2,000 ft.  Kept patchy/areas of
fog in the grids for the northern Ranchlands late tonight.  These
areas will have lighter winds and cooler temps, as well as having
been more fog-prone of late.  Overnight lows will be in the 60s most
everywhere.

Drier airmass in place (especially aloft) for Monday, with
precipitable water dropping further to 0.6-0.8".  Afternoon
dewpoints will mix down into the 50s except for areas near the
coast.  Sunshine will be plentiful, so most locales will add a
degree or two to today`s high temps, despite very little change to
H85 temps or 1000-500mb thicknesses.  This will put readings 6-10F
above normal for the RGV.  Monday night`s lows will be very similar
to tonight`s, with skies again mostly clear to perhaps partly cloudy.



.LONG TERM (Tuesday through Sunday):The 12Z GFS/ECMWF/Canadian
all remain in sync with the 500mb pattern and show little variation
over the last several days. Mid level ridge dominates the region
through Thursday with the advertise upstream mid/upper level
trough making its way across the Southern and Central Plains
Friday and Saturday. Unseasonably warm temperatures continue
through the week and rain chances look very slim to none with
very dry air in place.

Main sensible weather concerns: Thursday when the pressure
gradient will be the strongest as a deep surface low develops over
the Front Range of the Rockies. Model guidance has been persistent
for the strongest winds this day and latest package bumping up
surface winds another notch increasing the confidence factor for
wind advisory conditions (30-39mph). Friday`s and Friday night`s
slight chances for a shower or thunderstorm as the weak cold front
advances into the region. Confidence is dwindling as moisture
depth and content continues to be very limited. Have backed off on
overall coverage as has the GFS on probabilities. Then for
Friday and Saturday a possible heat spike as the front advances
and moves through the CWA. If the ECMWF has the right trend a
drier and s-sw flow Friday and very dry northwesterly winds
Saturday allow for temperatures to possibly climb into the upper
80s to mid 90s. GFS is not as hot Friday due its hanging on to the
slight chance of rain however it is not too far behind Saturday as
the dry air infiltrates the region next weekend.

&&

.MARINE:(Now through Monday Night): Observation sites on the Laguna
Madre currently measuring wind speeds right around 15 knots (with
some higher gusts).  Have opted not to highlight SCEC at this time
due to marginal character of winds.  Latest ob from Buoy 020 has SSE
winds of 9 knots with seas of 3 feet.  Gulf seas expected to remain
near 3 feet for the short-term, mainly due to continuing modest
swell from the SE.  Pressure gradient begins to tighten somewhat
Monday night, which may push winds over the outer Gulf waters to
near SCEC criterion.


Tuesday through Friday...Surface high over the Central Gulf and
mid level ridge over Texas and the Western Gulf to maintain a
light to moderate southeast flow and low to moderate sea Tuesday
and Wednesday. Pressure gradient strengthens Thursday and Friday
as a large low pressure trough moves into the Southern and Central
Plains. Winds and seas begin to increase peaking Thursday night
into Friday night. Small craft advisories are possible for all or
portions of the Coastal waters anytime Thursday through Saturday
morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  68  84  69  81 /   0   0   0   0
BROWNSVILLE          66  87  67  85 /   0   0   0   0
HARLINGEN            64  88  65  85 /   0   0   0   0
MCALLEN              65  90  66  90 /   0   0   0   0
RIO GRANDE CITY      64  92  65  93 /   0   0   0   0
SOUTH PADRE ISLAND   69  79  70  76 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

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