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Area forecast discussion 
National Weather Service Austin/San Antonio Texas
556 PM CST Friday Feb 27 2015

Update... /revised temperature trends...continue ww advisory/
late afternoon forecast update was to better align the temperature
forecast with current trends...as some of the forecasts min temperatures
are occurring early. Freezing weather grids were also adjusted
southeastward along I-35 to match where dry low level air shows a
potential to drop temperatures to freezing with the onset of
precipitation. Farther to the SW...dew point depressions are
approaching zero...and the somewhat steady rate of drizzle falling
into the shallow cold layer should eventually warm temperatures to
above freezing later tonight. Gridded data shows near steady
temperatures over most counties through late tonight...then
warming temperatures and a retreating freezing precipitation line
to reflect improving conditions closer to daybreak.

&&

Previous discussion... /issued 511 PM CST Friday Feb 27 2015/

Aviation...
MVFR and IFR ceilings are in place across all taf sites with every
site becoming IFR later this evening. Drizzle or light rain will
be possible through the evening and overnight. Temperatures at the
airports should remain just above freezing and will not mention
fzdz at this time. Models really strong warm air advection by
tomorrow evening and will mention LIFR ceilings and 1 mile
visibilities.

Hampshire

Previous discussion... /issued 337 PM CST Friday Feb 27 2015/

Short term (tonight through Saturday night)...
warm advection pattern is underway across south central Texas with
patches of light rain/drizzle forming. Temperatures have remained
below freezing in The Hill Country and along the Escarpment areas
with some reports of light freezing rain/drizzle. Have issued a
Winter Weather Advisory for The Hill Country to higher elevation
areas just west of the I-35 corridor through 10 am Saturday. Minor
ice accumulations are expected...although mainly on less traveled
roads...elevated structures...bridges and overpasses. Main impacts
will be along and north of a Comstock to Medina to Helotes to
Austin line. Temperatures will increase above the cold dome at the
surface which in turn will warm to above freezing as rain brings
down the warmer air from aloft with precipitation transitioning to
all rain late tonight into early Saturday morning. Have lowered
temperatures slightly as the cold dome is stubborn to erode.
Although...some erosion is possible from the coastal plains
Saturday night. Warm advection and isentropic lift will continue
the rain chances Saturday into Saturday night.

Long term (sunday through friday)...
cold dome finally looks to erode Sunday and Monday. Although...the
NAM/Gem maintain it while the European model (ecmwf) lifts it north and then brings
it back late Sunday into early Monday...finally moving it back
north late Monday. Have cooled temperatures a little for Sunday.
However...if the NAM/Gem verify...then temperatures would be a bit
cooler for Sunday and Monday. Warm advection and isentropic lift
continue the mainly light rain chances. All models finally lift
the cold air north by Tuesday which will be the warmest day of
this forecast as an upper level trough approaches from the west.
An upper level shortwave moving across the plains/Midwest forces
another Arctic cold front south across our area late Tuesday night
into Wednesday. Will maintain chances of showers and thunderstorms
as good moisture convergence and some instability is noted on
forecast soundings. Highs on Wednesday will be reached around
midday and then strong cold advection moves into south central
Texas. Forecast soundings show precipitation type transitioning to
sleet and snow across The Hill Country to along the Escarpment
areas Wednesday night and have introduced this mention to the
forecast. The trough moves east on Thursday ending the
precipitation. Freezing temperatures are expected again Thursday
and Friday morning.

&&

Preliminary point temps/pops...
Austin Camp Mabry 33 46 43 66 52 / 50 50 40 40 40
Austin Bergstrom international Airport 33 47 43 66 52 / 40 50 40 40 40
New Braunfels Muni Airport 34 47 45 68 55 / 50 50 40 30 30
Burnet Muni Airport 28 41 40 62 49 / 50 50 40 30 40
del Rio International Airport 36 49 45 70 55 / 20 20 10 - 10
Georgetown Muni Airport 29 44 41 63 49 / 50 50 40 40 40
Hondo Muni Airport 34 47 45 69 57 / 50 50 40 20 20
San Marcos Muni Airport 33 47 44 66 54 / 50 50 40 40 30
La Grange - Fayette regional 38 54 49 71 59 / 30 50 50 40 20
San Antonio International Airport 33 47 45 68 57 / 50 50 40 30 30
Stinson Muni Airport 36 48 46 69 58 / 50 50 40 30 30

&&

Ewx watches/warnings/advisories...
Winter Weather Advisory until 10 am CST Saturday for the following
counties: Bandera...Bexar...blanco...Burnet...Comal...Edwards...
Gillespie...Hays...Kendall...Kerr...Llano...real...Travis...Val
Verde...Williamson.

&&

$$

Mesoscale/aviation...29
synoptic/grids...18
public service/data collection...00

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