Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 210001 AAA
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
701 PM CDT TUE SEP 20 2016
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...High pressure and dry air aloft will keep the area
generally rain free through the forecast period...with only the
smallest of chances for a seabreeze shower Wednesday afternoon as
moisture begins a slow return. Surface high pressure over the
Northwestern Gulf will maintain light and variable winds overnight
and breezy ENE to E winds later on Wednesday.
.PREV DISCUSSION... /issued 308 PM CDT TUE SEP 20 2016/
SHORT TERM (Tonight through Wednesday Night): The 500 mb ridging
currently in place over the south central Plains states will weaken
a little throughout the short term period as an inverted trough axis
on the south side of the ridge moves west towards the RGV. IR satl
imagery shows a cluster of thunderstorms currently firing southwards
along the Mexican coastline indicating that the model initialization
on the inverted trough is fairly accurate. KBRO radar currently
shows some isold conv west over Hidalgo County firing along the sea
breeze boundary. This indicates that the atms is starting to moisten
up and destabilize. So will start walking up pops gradually through
tomorrow night as the trough axis gets closer. The approach of this
trough axis will also start impacting the high temps with the
gradual breakdown of the ridge axis lowering max temps a bit. Will
lean on the high side of temp guidance for highs and will go close
to a model blend for mins.
LONG TERM (Thursday through Tuesday): H5 ridge continues to hang
firm across central Texas, deflecting systems well to the north and
around the south edge. Models still have the inverted trough coming
inland starting later Wednesday and affecting the region through the
weekend. Models continue to indicate deeper moisture in the region,
with PW values above 1.9 through the weekend. The only inhibiting
factor is the densest moisture remains close to the sfc, so any
showers that attempt to pop up will have trouble gaining altitude.
Have minimal pop chances on Thursday, with slowly increasing rain
chances through the weekend as instability increases slightly. While
cloud cover may be a bit thicker over the weekend, most of each
afternoon will see ample daytime heating to push temps again into
the upper 90s to around 100.
MARINE: Now through Wednesday night: The expected MSL fields over
the Gulf of Mex will remain pretty benign through tomorrow night
which will maintain a fairly light easterly surface flow and low
seas. No SCA conditions expected through tomorrow night.
Modest southeast flow continues into the weekend with sfc
ridge across the eastern US. Winds will generally remain around 10
knots through Sunday, with sea swells reaching 2 feet. A weak front
will move into Texas late in the weekend, with a slightly tighter
gradient. Winds will approach 15 knots Sunday afternoon, which will
elevate seas to around 3 feet.
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