Area Forecast Discussion
Issued by NWS

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FXUS64 KLUB 251716

Area Forecast Discussion
National Weather Service Lubbock TX
1216 PM CDT Wed Apr 25 2018


IFR/MVFR conditions have improved to VFR at all terminals. This
afternoon skies will gradually clear. North winds will continue
throughout the day with wind speeds slowly decreasing. During the
evening and overnight winds will become light and variable before
shifting to the southwest tomorrow morning.

PREV DISCUSSION... /issued 340 AM CDT Wed Apr 25 2018/

At 730Z the CWA was dry, positioned between thunderstorms along/near
the frontal boundary stretching from the eastern Permian Basin into
the Big Country and rain showers associated with lift ahead of an
upper trough that extended from the northern Texas Panhandle into
southern Kansas. Gusty post-frontal northerly winds, generally
sustained at 20 to 30 mph, were common over the South Plains
region. Several spots across the northwestern and western zones
continue to occasionally stray into low-end advisory levels and we
will maintain the wind advisory across the western zones for now.
These winds will gradually decrease as the pressure gradient
relaxes and the current expiration time of 5 am for the advisory
looks pretty good, but we will watch trends and adjust if

Although no precipitation was reaching the ground in the FA early
this morning, stratus has quickly formed as relatively strong
isentropic upglide has developed above the cool surface ridging,
peaking near the 310K surface. This lift will continue through
12-15Z before quickly ending from northwest to southeast across
the CWA. The early morning lift should eventually yield scattered
light rain showers, with locations off the Caprock, where deeper
moisture and lift exist, being most favored. Up on the Caprock we
could see some light showers and sprinkles, though any amounts
will be minimal. There is about 500 J/kg of elevated CAPE too, so
if this can be exploited (which isn`t certain), isolated
thunderstorms and locally heavier precipitation will be possible.
Again, the best chance for a little thunder mixing in will be over
the eastern zones later this morning. Any precipitation should
quickly wane by around midday, except for the eastern Rolling
Plains where a few showers could persist into the early afternoon.
After the cloudy, breezy and cool start to the day, skies will
quickly clear from northwest to southeast yielding plenty of
insolation this afternoon. This will allow highs to recover into
the lower and middle 60s.

Mostly clear skies, light winds and relatively dry air will then
lead to a cool night. Given the favorable radiational cooling
conditions, we have gone slightly below the coolest MOS numbers,
with lows ranging from the middle and upper 30s across the
northwestern/western zones to lower 40s in the Rolling Plains.
Downslope breezes will develop early Thursday, but the next upper
level disturbance embedded in the north-northwest flow aloft will
bring a little mid-upper level moisture/lift along with another
cold front that will move through the South Plains during the
afternoon. The lack of low-level moisture behind the current storm
system will keep prospects for measurable precipitation nearly
nonexistent. Gusty northerly winds sustained at 20 to 30 mph will
be common behind the front though, and a few spots across the
northwestern zones could even threaten advisory levels again. Most
spots will see temperatures recover into the 70s before the FROPA
drops temperatures back into the upper 30s and lower 40s by early
Friday morning.

Progressive upper ridging in advance of a storm system moving into
the western states will then traverse the High Plains from late
Friday into early Sunday. This will fuel a gradual warming trend
while a prolonged period of southerly flow eventually carries
improved low-level moisture into West Texas. Westerly to
southwesterly flow aloft with then unfold late this weekend as the
western system progresses slowly eastward. Low thunder chances may
return along a surface trough in/near the western zones as early as
Sunday, though better storm chances may be Monday afternoon as a
dryline tightens and mixes eastward into the South Plains.
Obviously, plenty of smaller scale details can/will change between
now and then, but improving moisture/instability ahead of the
dryline and rising deep layer shear values will likely result in
an increasing chance for robust convection in and/or near the
area by early next week. The dryline will likely remain active
into the middle of next week as some form of western troughing
persists. However, the details of the trough will have to be
ironed out and it is unclear if the dryline will largely mix east
of the CWA by peak heating (under strong west-southwesterly flow
aloft) or if the upper flow will remain more meridional and the
dryline will stay further west in the South Plains region. Time
will tell, but at this point we have maintained low thunder
chances favoring the eastern zones toward the end of the forecast
with temperatures trending above average. West of the dryline
position fire weather concerns will be on the rise next week where
fuels are still receptive.




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