Area Forecast Discussion
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FXUS64 KLUB 160427

Area Forecast Discussion
National Weather Service Lubbock TX
1127 PM CDT Wed Mar 15 2017

Low level moisture was surging into the region late this evening
and may lead to fog early Thursday morning particularly at KLBB
and KPVW. Winds will veer to the southwest which is usually not
favorable for fog formation. This could possibly lead to very low
CIGS with no fog. After any fog and low CIGS dissipate by late
Thursday morning, winds will quickly increase out of the southwest
and become breezy.


PREV DISCUSSION... /issued 309 PM CDT Wed Mar 15 2017/

Surface low pressure slowly developing from eastern Colorado into
eastern New Mexico will shift slightly east overnight with modest
southerly low level flow across the Texas South Plains region. A low
level jet on the order of 30 to 35 knots between 850 mb and 875
millibar will help pull elevated dewpoints into the area, with short
range solutions still mulling over various low cloud outcomes. We
have leaned a little stronger towards the conceptual outcome of low
clouds with moisture lying so close, actually already increasing
this afternoon. Not so sure about fog potential, given modest
surface flow expected around 10 to 12 mph, so maintained as "Patchy"
as indicated by the previous forecast. Temperatures tonight of
course milder than the previous couple of nights. And any low clouds
early Thursday should burn off by midday; overrunning high clouds
expected to remain mostly thin. Surface flow will also veer slightly
downslope as very warm air moves in beneath a passing upper ridge
axis. Temperatures Thursday afternoon should shoot up 20 degrees
warmer than today for most of the area. RMcQueen

Thursday evening opens with weak height falls as a NW flow impulse
erodes ridging previously over the region. This disturbance in
concert with a more amplified Northern Plains` trough will drive a
cold front through the area on Friday. Am skeptical of models
slowing this front over the CWA during midday as history often
says such fronts prove more expedient. Therefore, sided with the
cooler high temp guidance for all but our far southern zones
where temps could quickly warm early in the afternoon with
compressional heating maximized ahead of the front. This boundary
should stall near or south of I-20 by early Saturday ahead of
northerly winds veering east during the day. A window for low
clouds advecting westward behind the front Fri night-early Sat
still looks plausible, but prospects for sufficiently deep moisture
and lift along the trailing elevated front are not robust enough
for even slight chance PoPs at this time.

Following progressive longwave ridging on Sun and unseasonably
warm thicknesses, uncertainty peaks on Mon regarding the amplitude
of troughing in southern Canada and its impact on cP air wedging
south through the Great Plains. Latest GFS is quite hawkish with
this scenario versus a more dovish ECM which favors even hotter
temps than Sun. Given the CMC is closer to the GFS, opted not to
stray much from the Superblend which captures this idea of an
earlier front in our NE zones on Mon. How much momentum
accompanies this front will obviously determine the quality of
Gulf moisture returning by midweek ahead of a respectable SW flow
trough progged upstream of the region.

Thursday afternoon may see periods of elevated fire danger over the
high plains, especially around the northwestern South Plains and
southwest Texas Panhandle. A very warm day is expected, with
temperatures 15 to nearly 20 degrees above normal, and relative
humidity dropping to 10 to 20 percent on the Caprock. Wind will be
marginal, but may increase close to 20 mph at times. RMcQueen




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