Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 170515

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1115 PM CST Thu Feb 16 2017

.SHORT TERM...(tonight through Sunday)
Issued at 307 PM CST Thu Feb 16 2017

A high-over-low mid-level pattern observed from the lee of the
Canadian Rockies to northwest Mexico this morning will break down
tonight into Friday in response to the progression of a polar-
branch short-wave trough through the northern Inter-mountain
Region into northern Plains. This disturbance will be associated
with a cold front at the surface which will advance east through
the Dakotas/mid MO Valley Friday into Friday night. Ahead of the
front, abundant sunshine coupled with southwest low-level winds
will yield optimal conditions for another day of well-above-
normal temperatures (i.e. mid 60s north to lower 70s south) across
much of our area. As such, the record high temperatures at Omaha
(69/1981) and Lincoln (72/1913) will again be in jeopardy of being
tied or broken. Additionally, this pattern will encourage very
high fire danger over southeast NE into southwest IA.

Friday night into Saturday, a surface high will build through the
mid MO Valley with slightly cooler, but still well-above-normal
temperatures (i.e. lower to mid 60s). On Sunday, the progression
of a multi-stream mid-level trough through the Interior West will
promote strengthening southerly winds and warming low-level
thermodynamic profiles. This warming may be offset to some degree
by increasing high-level clouds streaming north ahead of the mid-
level trough. Nonetheless, it still appears that temperatures will
again warm well into the 60s.

.LONG TERM...(Sunday night through Thursday)
Issued at 307 PM CST Thu Feb 16 2017

Sunday night into Monday, the aforementioned split-stream mid-
level trough will shift east into the Great Plains with associated
belts of strongest forcing for ascent remaining to our north and
south. Still, the combination of modest low-level warm advection
and the glancing influence of the polar-branch wave will be
sufficient to support increasing shower chances ahead of the
eastward-advancing cold front. While poor mid-level lapse rates
will limit the destabilization process, increasing low-level
moisture ahead of the front may contribute to sufficient
instability for an isolated thunderstorm or two on Monday.

A quasi-zonal mid-level flow pattern will exist over the northern
and central Plains Tuesday into Wednesday, with west to southwest
low-level winds supporting the continuation of daytime highs in
the 60s. By Thursday, 12z medium-range guidance is in reasonably
good agreement in suggesting that a potent mid-level trough will
emerge from the Rockies into central Plains, inducing a
relatively deep surface low. In contrast to the Sunday night-
Monday system, a plume of steep mid-level lapse rates is forecast
to associate with this synoptic cyclone, supporting an axis of
modest instability within the system warm sector. While details
remain uncertain at this juncture, it does appear that there will
be a risk for a few thunderstorms Thursday afternoon into night.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1114 PM CST Thu Feb 16 2017

LLWS at KLNK/KOMA through about 11-13z with winds at 2000 feet
from 240-250 degrees at 30-35 knots. VFR conditions otherwise.




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