Area Forecast Discussion
Issued by NWS

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FXUS64 KLUB 180612 CCA

Area Forecast Discussion...CORRECTED
National Weather Service Lubbock TX
112 AM CDT Sun Mar 18 2018

Plenty of things to consider this TAF cycle. Early on, improving
moisture will bring the risk of MVFR cigs developing at KCDS.
Additionally, top-down moistening from an approaching subtropical
disturbance will result in increasing mid-high clouds over all of
the terminals. In fact, confidence is increasing that a few light
showers will move across the area later this morning, perhaps
linger at KCDS into the early afternoon. These showers could
potentially bring enough moisture to briefly drop cigs below VFR
levels at KLBB or KPVW, but confidence in this is low. Instead,
much drier air will overspread the Caprock on rapidly increasing
southwesterly winds, particularly by mid to late afternoon. It
still looks like an AWW will be needed for KLBB at some point,
probably valid after 21Z. The strong winds will also loft BLDU
which may drop visibilities to MVFR at KLBB (and perhaps KPVW)
late this afternoon into early this evening. Strong winds will
continue into the night, turning more westerly behind a Pacific
front this evening. KCDS should escape the strong winds until the
front moves through there this evening. However, KCDS may deal
with sub-VFR cigs through much of the morning hours before they
scatter and lift.


We have decided to add a shower mention for most of the South
Plains region Sunday morning (12-18Z). Top down moistening will
continue to occur as a subtropical disturbance races up and over
the area in the brisk southwesterly flow aloft well in advance of
the primary storm system that will bring the strong winds and fire
weather concerns later in the day. Most of the NWP consulted,
including the short-term, high-resolution guidance, now suggests
a brief window for isolated to scattered light showers to race
northeastward across the South Plains region later this morning.
There may even be just enough elevated instability for a few
rumbles of thunder, particularly the further east you go off the
Caprock. Any rain chances will quickly shift east of the edge of
the Caprock by around midday.


.PREV DISCUSSION... /issued 328 PM CDT Sat Mar 17 2018/

Solutions continue to tighten grouping on the storm expected to
deepen from the 4-corners into the northwest Texas Panhandle late
Sunday. Wind fields will increase aloft - just over 100 knots at
the 500 millibar level - by late Sunday and crossing our northern
zones Sunday night. Surface pressures will fall Sunday afternoon
and evening and a Pacific Cold front will push through as well
late Sunday. Anyway, all ingredients seem in place for a strong
and potentially high wind event developing late tomorrow and
possibly continuing overnight and into early Monday. We opted to
issue a Wind Advisory area-wide Sunday afternoon through 7 am
Sunday morning and let next shifts determine need for a High Wind

In advance, we will see continued southwest flow of mid level
moisture, and possibly a burst of lift enough for sprinkles or
light showers via top-down moistening early Sunday before
encountering enough instability in our east/northeast counties to
mention a low chance of thunder. Did not play the sprinkles at
this point - believe the WRF/NAM is overplaying the moisture and
lift - but acknowledge the possibility.

After the storm passes Monday, a Canadian-type cold front will
push southward lowering temperatures near or a little below normal
Tuesday. Flow should quickly return to the southwest Wednesday
with increasing breezes and further warming later in the week as
the next round of upper troughing spreads through the
intermountain west. RMcQueen

With the tightening grouping/increasing confidence in models the
pattern late Sunday is more closely resembling the classic
Southern Plains outbreak pattern. Timing is still a little
unclear - the storm still could be slow enough to delay strongest
winds until Sunday evening - but close enough for us to issue a
Red Flag Warning area-wide Sunday afternoon and Sunday night. We
have added more critical wording to some of our products in
preparation for this storm - the Storm Prediction Center is a bit
reluctant to go Extremely Critical yet, but this is possible. So,
watch for possible further upgrade in product wording overnight.

On Monday, strong northwest winds are likely to start the day and
may develop into critical fire weather conditions again. Opted
against extending the Red Flag Warning through Monday, or a Fire
Weather Watch, to guard against product overload and allow later
shifts a little more flexibility in product handling. But, be
aware Monday looms as a possible critical day.

A lull Tuesday will be followed by improving south to southwest
breezes Wednesday and beyond in advance of the next round of
storminess moving into the intermountain west late next week.
Elevated or Critical fire weather conditions will be possible at
least Thursday through next Saturday. RMcQueen


Red Flag Warning from noon today to 7 AM CDT Monday for

Wind Advisory from 2 PM this afternoon to 7 AM CDT Monday for



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