Area Forecast Discussion
Issued by NWS
FXUS64 KLUB 271121
Area Forecast Discussion
National Weather Service Lubbock TX
521 AM CST Sun Nov 27 2016
Current IFR conditions at KLBB and KPVW should persist through
mid-morning with primarily MVFR expected at KCDS over the same
time. Once conditions improve rapidly around noon we`ll see windy
conditions with chances of blowing dust.
.PREV DISCUSSION... /issued 254 AM CST Sun Nov 27 2016/
Very little change in forecast. Strong low level moisture advection
continues across West Texas during the overnight out ahead of
deepening upper level trough approaching from the west near the Four
Corners region. Current surface obs indicate nearly full saturation
at the surface on the Caprock with 3 to 5 degree dew point
depressions across the Rolling Plains. South Plains and Southwest
Texas Panhandle may see patchy fog develop from now through a couple
hours past sunrise along with low level stratus deck through the
morning hours. First embedded shortwave associated with approaching
system will track ESE through the Texas Panhandle by mid morning and
may provide just enough lift for light showers across much of the
CWA. Unfortunately any upper level instability will be too
progressive and not quite dynamic enough to tap into available
moisture for more rainfall. The window for best chance of precip in
pre-frontal airmass and associated mid level omega lift through mid
morning hours will close abruptly as strong southwesterly winds
behind Pacific cold front, scour deep surface moisture out beginning
around noon from west to east across the region and drier air works
its way to the surface.
Low level jet max of 60kts peaks late morning as the first wave
of the deepening trough begins to lift north and second impulse of
energy barrels southeast out of southern California and southern
Nevada. As the base of the trough deepens and widens and dry air
spreads rapidly eastward across our area we`ll transition toward a
wind event and marginal concerns for fire weather conditions. The
wind advisory was expanded for the afternoon and evening hours
across locations on the Caprock where we expect to see sustained
southwesterly winds of 30 to 35 mph during that period.
Downsloping of strong winds will lead to highs well above normal
in the mid to upper 60s on the Caprock and low 70s in the Rolling
Plains. The Pacific front will come with strong winds but the
trailing air mass won`t be terribly cool, with near normal temps
for the overnight into Monday.
Windy conditions to persist Monday and Tuesday as the forecast
area will remain on the southern periphery of a broad long wave
trough covering much of the continental U.S. This trough will be
anchored by a deep closed low over the Northern Plains. Mid level
jet energy rounding the base of the trough will translate to the
surface both days. Wind advisory speeds are looking increasingly
likely for the southwestern half of the forecast area Monday. The
mid level speed max will get shunted southward enough Tuesday to
allow wind speeds to decrease a bit.
Wednesday will begin to see the transition to nearly zonal flow
aloft through Thursday night. Cool surface air behind a cold front
that will move through the forecast area Tuesday afternoon and
evening will result in cooler temperatures Wednesday followed by a
modest rebound with southwesterly low level flow Thursday.
Friday will usher in the next change to the pattern. A closed low
will dig southward past the Great Basin and Desert Southwest into
northwestern Mexico. Increasing south-southwesterly mid level
flow will transport deep moisture into the region while a cold
front will bring colder temperatures in as early as Friday
afternoon. The warm-conveyor belt over the southern Plains will
begin to generate precipitation as early as Friday with increasing
chances Friday night and Saturday. The progged temperature
profile is a detail that will likely see quite a bit of massaging
through the week. Will keep it simple at this time and favor a
rain/snow mention. Have narrowed the diurnal temperature range
both Friday and Saturday in line with the local blend of models.
Will likely see further narrowing as the week progresses as the
pattern suggests little diurnal variation likely.
Despite strong winds associated with a Pacific front pushing through
our area midday and dry air quickly spreading over the region, the
deep surface moisture advection out ahead of the approaching system
should keep RH values above minimums for any sustained fire weather
concerns. Elevated dewpoints are certainly the limiting factors, if
drier air moves in faster than guidance is suggesting these
conditions could change for the worse quickly.
Relative humidity will be the limiting factor again Tuesday.
Despite strong winds across the southwestern half of the forecast
area and lower dewpoint temperatures, cooler temperatures will
result in relative humidity staying above 20 percent.
Wind Advisory from 11 AM this morning to 5 PM CST this afternoon