Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 180525

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1125 PM CST Wed Jan 17 2018

Based off of the recent trends in the GOES-16 satellite imagery,
the deck of mid-level cloud still SW of the region is continuing
to struggle with the swath of very dry air in place across SE TX.
A very slow northeasterly progression has begun in some
locations along this boundary. As a result, have slowed the
entrance of cloud cover across the northern and metro TAF sites
by an hour or two Thursday afternoon. LBX will be the first
terminal to be impacted by these mid-level clouds, and UTS should
be the last. Although VFR conditions are expected to hold through
most of the TAF period, guidance is indicating the potential for
this deck to lower and thicken, resulting in borderline VFR to
MVFR ceilings late Thursday afternoon and into the evening hours.
Northeast winds will veer to the east and remain between 5-10kts
through the day Thursday.



.PREV DISCUSSION... /ISSUED 919 PM CST Wed Jan 17 2018/

Kind of a tough temperature forecast tonight as clouds try to move
into the region from the southwest but the cloud shield continues
to contract as it encounters significantly drier air to the
northeast. The air mass to the NE is dry with surface dew points
between 10-15 degrees and fcst soundings and x-sections show a dry
profile from the sfc to 500 mb. Winds are light so coupled with
the dry air mass in place, ideal radiational cooling should
occur. Since the cloud shield is not expected to arrive until
after 12z, have decided to add both Austin and Colorado counties
to the Hard Freeze Warning. Colorado county may be a bit of a
stretch but Columbus is currently 25 so even if clouds move in,
the criteria will probably still be met. Temps at Houston have
been slow to fall this evening but parts of Harris County will
fall below 25 by morning. Over the southwest part of the area,
fcst soundings show some saturation between 6-7000 feet but the
sub-cloud layer is very dry. Temps remain aoa freezing where the
clouds are located. Leaned toward the ECMWF cloud product for
Thursday and would expect widespread cloudiness by mid afternoon.
The cloud cover will likely retard heating and afternoon temps
are trending a bit cooler. Should make the lower 40s and thats
about it. Won`t be much of a temperature drop tomorrow night as
onshore winds and cloud cover help to insulate. 43


College Station (CLL)      38  22  42  31  52 /   0   0   0  10  30
Houston (IAH)              38  23  43  35  53 /   0   0   0  10  30
Galveston (GLS)            37  31  42  42  55 /   0   0   0  10  50


TX...Hard Freeze Warning until 9 AM CST Thursday for the following
     zones: Austin...Brazos...Burleson...Chambers...Colorado...
     Montgomery...Polk...San Jacinto...Trinity...Walker...

     for the following zones: 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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