Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 230847
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
347 AM CDT Mon Oct 23 2017

.DISCUSSION...
At 3 AM, surface high pressure was located over deep South Texas
with northerly winds bringing drier air into the region. Surface
dew points are in the upper 40s to lower 50s. Ideal radiational
cooling is ongoing and temperatures have already fallen into the
upper 40s to mid 50s over most of the region and a further drop
before sunrise is likely. The dry nature of the current air mass
should allow for a large diurnal range in temperatures today and
high temperatures today warm to around 80 degrees under full sun.
A secondary surge of colder and drier air should cross SE TX
tonight. Tuesday and Wednesday look cooler and drier. Elevated
fire weather conditions look possible on Tuesday as RH values fall
near or below 25 percent and north winds increase to around 15
mph. It remains dry on Wednesday but winds are progged to be
lighter. 850 mb temps are near 5 C on Wednesday and bringing that
down dry adiabatically only produces high temps in the mid/upper
60s. Numerical guidance is significantly warmer so split the
difference between the two camps for high temps. Onshore winds
return Wed night and a warm up begins on Thursday. A cold front
will cross the region on Fri morning and moisture is not looking
too impressive at this time with PW values reaching 0.90 inches.
Will carry 20 PoPs with the front on Friday. The ECMWF is still
advertising a weak isentropic upglide event in the wake of the
front but the EC is now trending faster with the front and
associated upper level trough. The Canadian looks similar to the
GFS so have leaned toward the drier solutions for next weekend. 43

&&

.MARINE...
Winds will continue to diminish across the coastal waters and bays
today as a surface high pressure area moves across the Texas coastal
areas. The next front will move off of the coast late Monday night.
Offshore winds behind this front will reach advisory levels Tuesday
morning and persist through Tuesday night. Another surface high
pressure ridge will move overhead and help diminish winds below
criteria Wednesday morning. Onshore winds are expected by Thursday.
Another strong front is expected to move off of the coast on Friday.

40

&&

.FIRE...
Elevated fire weather conditions are expected today through
Wednesday with Tuesday the driest day. Minimum relative humidity
values will fall to between 25 and 30 percent this afternoon, around
25 percent on Tuesday, and 25 to 30 percent on Wednesday. Light
winds of about 5 mph are expected today away from the coast. The
coastal counties should see northerly winds of 5 to 10 mph. A cold
front will move across Southeast Texas tonight and move off of the
coast early Tuesday morning. Winds behind this front will reach from
15 to 20 mph during Tuesday afternoon. A deep layer of 25 to 30 mph
winds will persist above the ground surface Tuesday afternoon as
well. The wind speeds will diminish on Wednesday and speeds will
likely only range from 5 to 10 mph inland to about 10 mph near the
coast. Onshore winds will help return Gulf moisture back across the
area on Thursday.

40

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      81  54  74  46  74 /   0   0   0   0   0
Houston (IAH)              80  56  74  50  72 /   0   0   0   0   0
Galveston (GLS)            80  65  75  60  72 /   0   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 10 AM CDT this morning
     for the following zones: Coastal waters from Freeport to
     the Matagorda Ship Channel out 20 NM...Coastal waters from
     High Island to Freeport out 20 NM...Waters from Freeport to
     the Matagorda Ship Channel from 20 to 60 NM...Waters from
     High Island to Freeport from 20 to 60 NM.

&&

$$


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