Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 241139
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
539 AM CST Fri Feb 24 2017

.SHORT TERM...(today through Sunday)
Issued at 338 AM CST Fri Feb 24 2017

...A winter storm will continue to impact area today...

Early-morning water vapor imagery depicts a vigorous mid-level low
edging east from the central Rockies into western parts of NE and
SD with an associated negatively tilted short-wave trough
advancing through the mid and lower MO Valleys. The initial burst
of convective precipitation associated with the short-wave trough
and accompanying plume of steep mid-level lapse rates has shifted
to the east of the area. In the wake of the lead short-wave
trough, 09z mosaic radar data indicate an evolving deformation
snow band from southeast SD through northeast into central NE.
Immediately ahead of the snow band, the intrusion of dry mid-
level air within the system dry slot has resulted in areas of
freezing drizzle across portions of southeast and east-central NE.

Latest short-term model guidance remains consistent in suggesting
that the evolving deformation snow band will pivot east across the
forecast area today with the potential for an additional one to
four inches of snow within the winter storm warning and winter
weather advisory areas. When coupled with north winds of 20-30 mph
with higher gusts, areas of blowing and drifting snow are expected
which will create hazardous travel conditions. These conditions
will be further exacerbated in areas where more persistent
freezing drizzle occurs this morning.

Based on the model guidance mentioned above, it appears that the
snow will end this afternoon across our northwest counties, and
by early evening in western Iowa. As such, we have adjusted the
the expiration times of the warning and advisory accordingly.

While the fresh snow will have modulating effects on temperatures,
it does appear that we will see gradually warmer daytime temperatures
through the weekend.

.LONG TERM...(Sunday night through Thursday)
Issued at 338 AM CST Fri Feb 24 2017

A broad, cyclonic mid-level flow regime in place at the onset of
the extended range is forecast to amplify in response to the
progression of a positively tilted trough from the Interior West
into the Great Plains during the first half of the upcoming work
week. In the low levels, a cold front attendant to this upper-air
system will advance southeast through the mid MO Valley Monday
night with low-probability chances for measurable precipitation
ahead of and along this boundary Monday/Monday night.

A transition to a northwest flow pattern aloft is forecast during
the latter half of the week with dry and gradually warming
conditions expected.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 536 AM CST Fri Feb 24 2017

Snow will bring reduced visibilities and lowered ceilings to all
sites today, and particularly this morning. Ceilings will mainly
be in the low-end MVFR range, with some intermittent IFR
conditions, while visibilities will mainly be in the IFR range.
Conditions will improve through the afternoon, earliest at KOFK
and latest at KOMA, as the system moves east. By around 22-02Z,
all sites should be at VFR conditions, continuing through the rest
of the TAF cycle. Gusty north winds will increase yet this
morning and turn more northwesterly, with speeds decreasing to
around 10-12kt by around 02-06Z.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Warning until 9 PM CST this evening for NEZ034-044-
     045.

     Winter Weather Advisory until 9 PM CST this evening for
     NEZ051>053-066-067.

     Winter Weather Advisory until 6 PM CST this evening for NEZ050-
     065.

     Winter Storm Warning until 6 PM CST this evening for NEZ011-012-
     015>018-030>033-042-043.

IA...Winter Storm Warning until 9 PM CST this evening for IAZ043-055.

     Winter Weather Advisory until 9 PM CST this evening for IAZ056-
     069-079.

&&

$$

SHORT TERM...Mead
LONG TERM...Mead
AVIATION...Mayes


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