Area Forecast Discussion
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FXUS64 KLUB 141136 AAA

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
536 AM CST Wed Feb 14 2018

VFR conditions in place at KLBB and KPVW but KCDS is
intermittently bouncing between MVFR and VFR. KCDS should continue
to do this through mid morning before going VFR through the rest
of the day. Wind will pick up from the southwest through the
afternoon as well. VFR conditions will continue through this
evening but there could be some MVFR clouds ceilings after
midnight Thursday morning towards the end of this TAF cycle but
confidence is too low to include at this time.



.PREV DISCUSSION... /issued 409 AM CST Wed Feb 14 2018/

Broad southwesterly flow aloft downstream of an upper low off the
coast of southern California is drawing plenty of mid-upper level
moisture off the eastern Pacific and over the region early this
morning. This flow regime will persist the next couple of days as
the upper low quickly opens and ejects tonight and is replaced by a
shortwave digging through the Great Basin tomorrow. Surface
troughing in the lee of the Rockies will promote breezy downslope
flow today and again tomorrow. The shallow moisture that has
returned to the eastern half of the CWA early this morning, and
could provide patchy fog over the far eastern zones the next several
hours, will be advected eastward. This will leave a warm, dry and
breezy afternoon which will also act to increase the fire danger.
The abundant high clouds could temper heating and deep mixing just a
bit, but temperatures will still climb well into the 70s, with a few
lower 80s possible. After another mild night tonight, winds will
turn more westerly behind a weak Pacific front associated with what
remains of the former upper low as it emerges well to our north. The
winds will again be solidly on the breezy side, likely a few knots
higher than today. These downslope winds will promote another warm
day, and even under plenty of mid-high clouds and behind the Pacific
front, highs will range from the upper 60s across the southwest
Texas Panhandle to lower and middle 80s in the Rolling Plains. Even
with the dry lower levels, we can not completely rule out a rogue
shower today or tomorrow as the Pacific moisture streams over the
region, though virga will be the more likely outcome.

A strong cold front will follow early Friday, with gusty northerly
winds and much cooler and relatively dry air in its wake. At the
same time, the positively tilted western trough will impinge upon
the elevated Pacific moisture, with a favorable upper level jet and
some elevated frontogenesis likely leading to the development of a
west-southwest to east-northeast band of precipitation on Friday.
NWP, aside from the NAM, do show a band of light precipitation
expanding from southern NM into southern OK, cutting across the
southern half or so of our CWA. Models have generally backed off on
precipitation amounts through the day on Friday, and this seems
reasonable given the dry low-level air that will be cutting under
the moist flow aloft. The latest trends favor our best
precipitation chances Friday night before the upper wave quickly
exits east early Saturday. We have followed these trends, and now
reflect the highest PoPs between 00Z and 12Z Saturday, with values
ranging from 20 percent across the northwest zones to 50-60
percent over the southern/southeastern zones. Regarding p-type,
most indications favor a chilly rain, while temperatures perhaps
holding steady or even warming slightly Friday night as low-level
flow swings back around to the south. Still, with forecast lows
near freezing, and some question marks regarding the temperature
profile, we do reflect and rain and freezing rain mix for all but
the southern and eastern most zones late Friday night. Before
then, as the initial post-frontal air builds in on Friday, the
increased potential for evaporative cooling could bring some risk
of a wintry mix, that is if the dry air doesn`t completely thwart
precipitation altogether. For now we have maintained only a rain
mention in the grids during the day Friday with highs stuck in
the lower to middle 40s.

A quick recovery to near average temperatures will follow on
Saturday with even warmer temperatures on Sunday as southwesterly
flow aloft (and southerly low-level flow) return in advance of the
next iteration of western troughing. We may even see a dryline
attempt to setup early next week with a chance of showers/storms
possibly flirting with our far southeast zones at times, though
the better shot will likely remain off to our east. Instead, fire
weather concerns may be more likely here as dry, warm and breezy
conditions spread across the Caprock. Eventually another cold
front may move into the South Plains by Tuesday or Wednesday as a
portion of the western trough translates eastward.

Warm, dry and breezy conditions will result elevated to briefly
critical fire weather over most of the area this afternoon. RH
values may dip below 15 percent, though wind speeds are generally
expected to remain sub-critical. A fire danger statement (RFD) will
be issued for all but the southern Rolling Plains valid from midday
to 6 pm. Tomorrow will bring another round of gusty, dry and warm
winds. Wind speeds may actually be a little stronger than today, but
RH values are also expected to be higher, generally above 20




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