Area Forecast Discussion
Issued by NWS

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FXUS64 KLUB 131714

Area Forecast Discussion
National Weather Service Lubbock TX
1114 AM CST Wed Dec 13 2017

VFR conditions will continue although a cold front was currently
moving through the region. Winds will continue to shift around to
the north-northeast during the early afternoon with speeds around
15kt. Speeds will decrease by early evening.


PREV DISCUSSION... /issued 330 AM CST Wed Dec 13 2017/

The only features of interest on satellite imagery this morning
consisted of a stationary upper low over Baja California and an
Alberta Clipper found diving southeast across the Dakotas. As this
latter wave zips along the remainder of the Missouri River today,
it will send a modest cold front across our area by midday ahead
of gusty northerly winds. Dry low levels ahead of this front will
see little change following FROPA. This along with more above
normal temps will set the stage for an elevated wildfire event,
but this should fall short of critical levels given 20-foot winds
largely under 20 mph. A Rangeland Fire Danger statement will be
issued from 11 AM to 6 PM for the entire area.

By tonight, another trough emanating from the Canadian Rockies
looks to take a more westerly longitude and dive straight south
roughly along the Continental Divide, before reaching the Colorado
Plateau by daybreak Thursday. The GFS has come around to the
ECMWF in terms of this trough`s sharper amplitude and improved
upper divergence, so as such we have increased cloud coverage in
anticipation of a much greater influx of mid-level clouds. Model
soundings do show rather stout sub-cloud moisture deficits during
this trough`s passage Thursday afternoon, so precip (if any)
would only be a few spritzes of rain or snowflakes, and largely
confined to our NW zones near the better lift. This is a footnote
at best, so no precip mention was inserted in the forecast grids.

For Friday through the weekend, recent models have unfortunately
abandoned their earlier continuity of a progressive open wave over
the region in favor of a slower and sharper trough arriving in NW
flow. The scenario is complicated by the aforementioned Baja low
that is now progged to partially phase with the northern stream
trough before lifting NE across the Lone Star State late Saturday
night. The upshot is that following a break in clouds on Friday,
a quick return to mid and high clouds could ensue by Saturday
ahead of the Baja wave and its finger of high level subtropical
moisture. At the very least, backing of low level winds should
pull up a bit more moisture which would serve to curb high temps
and wind speeds a bit. Ultimately, Saturday`s pattern is no longer
a favorable wildfire setup, but may still result in a sub-critical
event pending how much cloud cover ensues. Confidence is very
low in any of this moisture transitioning into precip over our
area by late Saturday as the Baja wave passes just south of the
area, so have left PoPs silent for now. This theme also applies to
the kicker wave`s arrival on Sunday and any prospects for precip,
but a stronger cold front by early Sunday is still on track.

For next week, a more zonal flow across the CONUS will breed a
steady moderating theme in our temps before this pattern breaks
down and trends colder toward the weekend. As alluded to in
earlier discussions, this sharper pattern change still possesses
a cross-Polar flow with Arctic air invading a sizable portion of
the Lower 48. Should this strongly meridional flow evolve by late
week, then our temps could easily plummet to well below normal
territory - just in time for Christmas.




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