Area Forecast Discussion
Issued by NWS
FXUS64 KLUB 261141
Area Forecast Discussion
National Weather Service Lubbock TX
541 AM CST Sun Feb 26 2017
VFR will be the rule today with some passing mid-high clouds.
Winds will be light but somewhat variable at KCDS while modest
westerly breezes affect KLBB and KPVW. VFR will persist tonight on
the Caprock, though KCDS could see low clouds and/or fog threaten
KCDS late. Confidence in sub-VFR conditions at KCDS after
midnight is too uncertain to insert in the TAF at this point.
.PREV DISCUSSION... /issued 536 AM CST Sun Feb 26 2017/
After two consecutive days of below average temperatures we will
swing back to warm side of average today. This will occur as stout
westerly flow aloft persists downstream of a weakening upper
disturbance that will accelerate across the Desert Southwest through
the day today. A good fetch of Pacific moisture will bring periods
of mid-level and high cloud over the region through the day though
no precipitation. At the surface, a weak boundary will sag into the
northeast zones keeping winds of a light northerly to easterly
persuasion there. Elsewhere dry downsloping breezes will help
temperatures warm up into the 60s, with lower 70s also possible
across the southern zones.
Clouds will thicken further this evening with the approach of the
upper disturbance and we could even see a few virga showers though
dry air below 600 mb will keep measurable rain chances quite low.
The clouds will quickly clear from west to east late tonight as the
shortwave trough shifts to our east. As it passes low-level Gulf
moisture will be drawn northward through the center part of the
state. This moisture could briefly flirt with our far eastern zones
bringing a risk of low-clouds and/or fog from 06-12Z. Current NWP
generally keep the fog just east of the CWA and thus we have left it
out of the grids, but we will have to keep an eye on this.
Otherwise, lows will be fairly close to late February norms.
The main concerns in the extended are for elevated to critical
fire conditions on the Caprock Monday, and then strong winds and
critical fire conditions across most of the forecast area on
Strengthening southwest flow aloft over the southern plains and
cyclogenesis across southeast Colo and eastern NM will promote and
increase in southwest breezes on Monday. Temperatures should warm
quickly in the pattern and we`ve trended highs up from blended
guidance toward the MOS output.
On Tuesday, an upper trough will quickly advance from the Great
Basin and desert southwest toward West Texas. As it does, a strong
mid to upper-level jet will overspread West Texas. A surface low
will deepen across the TX and OK Panhandles, tightening the
surface trough as it slides east across the forecast area. The
result should be a windy day. Considerable high-cloudiness may put
a slight damper on the winds, but we don`t expect cloud cover to
prevent the winds from reaching firmly into the advisory category
(30-39 mph sustained) during the afternoon on the Caprock with
some potential for high winds in the far southwest Texas
Panhandle. Unfortunately, winds of this magnitude should generate
some blowing dust and we`ve added a mention to the forecast. The
trough axis shifts east overnight allowing for a rather sharp
front to pass through early in the morning Wednesday. It should
remain breezy as the front passes Wednesday morning, but the
pressure gradient and winds will relax during the day as the
front moves on toward the GOM. It will be cooler Wednesday and
Thursday while remaining dry. Warmer temperatures are then
expected to return heading into next weekend as a low altitude
trough passes to our south.
After two relatively cool days we will see temperatures climb 5 to
10 degrees above average this afternoon. This warmth combined
dewpoints in the teens and single digits will create RH values of 10
to 15 percent over a good chunk of the South Plains into the western
Rolling Plains. However westerly breezes will be on the lighter side
in the dry air, generally sustained in the 5 to 15 knot range. A few
spots could see brief periods of elevated fire weather, but the
relatively low magnitude of the wind should keep the overall fire
danger in check today and no highlights are planned.
Additional warming and drying will occur across the area Monday
into Tuesday. Temperatures will be about 10 to 15 degrees above
average both days. The recent dry period will continue to prime
fuels. In addition, wind speeds will be on the increase as a
upper-level storm system approaches from the west. The fire
danger will become elevated across most of the Caprock Monday
afternoon as RH values fall to near 15 percent and wind speeds
rise into the 15 to 25 mph range. A Fire Weather Watch was not
issued as the current forecast does not support three hours of RH
values 15 percent or less in the area of strongest winds (western
areas). However, if forecast RH values trend down, A Watch or Red
Flag Warning may become necessary.
Tuesday appears to have greater potential for more widespread,
solid Red Flag conditions due to an increase in wind speeds. Winds
speeds of 30 to 40 mph with gusts to near 50 mph are currently
indicated across the Caprock. However, moisture levels may remain
marginal. If confidence in lower moisture levels improves, a Fire
Weather Watch is likely to be issued for Tuesday.