Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Amarillo Texas
522 am CST Wednesday Mar 4 2015
12z taf cycle
an upper trough will approach the panhandles from the west today and
then move across the area by this evening and early tonight. Light
snow will result in MVFR visibilities and IFR to LIFR or vlifr
ceilings through around 00z to 02z Thursday. VFR conditions are
expected to return after 00z to 02z Thursday as the upper trough
moves off to the east and drier conditions allow for decreasing low
cloudiness tonight. Northerly to northeasterly winds 10 to 20 knots
will increase to around 15 to 25 knots with higher gusts after 14z to
15z today...and then winds diminishing after 00z Thursday to around 5
to 15 knots.
Previous discussion... /issued 445 am CST Wednesday Mar 4 2015/
Short term...today and tonight
cold front has pushed south of the Texas and Oklahoma panhandles
early this morning while aloft the upper low is centered over western
old Mexico. Current Doppler radar reflectivity shows a band of snow
in south central Kansas with an area of light rain well south and
southeast of the area. Although the Texas and Oklahoma panhandles
seem to be in between these areas of precipitation...still looks like
a good chance for wintry precipitation to develop and move across the
panhandles today. Qg forcing and isentropic lift over the cold moist
air at the surface will increase later this morning and this
afternoon...coincident to when the bulk of the precipitation will
occur. The Arctic air mass behind the cold front will continue to
deepen this morning...although it may take some time for the elevated
warm layer to erode across the central and southern Texas Panhandle.
Furthermore forecast soundings also indicate quite a bit of middle-level dry
air particularly over the central and southern Texas Panhandle which
would limit the production of ice nuclei in the snow growth zone.
Top-down moistening will increase moisture in this dry layer
throughout the morning. So while precipitation type is expected to be
light snow across the Oklahoma and northern Texas panhandles
today...there will be a transition from a wintry mix of freezing
drizzle...light snow...and sleet to snow by midday over the central
and southern Texas Panhandle. While snowfall accumulations will only
range from 1 to 3 inches...roads will likely become slick and
hazardous throughout the day. In addition northerly winds of 15 to 25
miles per hour can create some areas of blowing and drifting snow...likely
contributing to the potential hazardous driving conditions. Given
these anticipated travel impacts...will continue the current Winter
Weather Advisory both spatially and temporally.
Forcing for ascent quickly wanes this evening as the upper low
weakens as it slides across The Four Corners region. Light snow will
end this evening while surface high pressure building into the area
will cause surface winds to become light while gradually backing out
of the west late tonight. Cloud cover will also thin...helping to
support lows in the teens over the area.
Long term...Thursday through Wednesday
the upper trough will pass over the panhandles Thursday while a high
amplitude upper ridge builds over the western Continental U.S.. the surface high
slides off to the southeast...causing surface winds to further back
out of the southwest. However despite the downsloping southwesterly
low-level flow...temperatures will remain quite a bit below normal
with highs expected to only climb into the upper 30s to the lower 40s.
Temperatures will continue to warm throughout the extended portion of
the forecast will upper ridging remaining across the western Continental U.S..
a couple of upper disturbances will pass north of the area through
the period while an upper-level low lifts northeast across The Four
Corners region over the weekend. The lack of moisture will likely
maintain dry weather conditions. Biggest forecast challenge will be
temperatures as the mex guidance is quite a bit warmer than the ece early
next week. Since ensemble guidance shows high spread in temperatures
have generally accepted the superblend with highs in the 60s.
Texas...Winter Weather Advisory until 6 PM CST this evening for the
following zones: Dallam...Hansford...Lipscomb...Ochiltree...
Winter Weather Advisory until midnight CST tonight for the
following zones: Armstrong...Carson...Collingsworth...Deaf
OK...Winter Weather Advisory until 6 PM CST this evening for the
following zones: Beaver...Cimarron...Texas.