Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 222124
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
324 PM CST Wed Feb 22 2017

.SHORT TERM...(tonight through Saturday)
Issued at 241 PM CST Wed Feb 22 2017

...Winter storm with near blizzard conditions will affect part of
the forecast area Thursday night through Friday night...

The calm before the storm today, with another record record
breaking day at both Lincoln and Omaha with highs in the mid 70s!
This will be in stark contrast to the expected wintry weather that
develops by the end of the work week.

Upper low across western US with 60-80 meter height falls and a
100-120 knot 300mb jet will close off tonight and then cross the
Rockies Thursday then eject onto the Plains Thursday night and
Friday.

Dry weather expected tonight with northerly flow behind a cool
front that has moved through the area. Surface cyclogenesis
develops across the western High Plains Thursday then moves east
northeast in a favored trace to bring heavy snow to the much of
the central and northern Plains, and even a thunder threat in
southeast NE and southwest IA within a dry slot.

Early Thursday morning should be dry, but a rain/snow mix will be
spreading eastward along the SD border area into northeast NE
through the day. Meanwhile, thunderstorms may develop along south
of I80 through mid afternoon Thursday into Thursday evening,
although the 12z High-res ARW/NMM models and now most the 18z ESRL
HRRR suggest these storms could even be south of the forecast
area in northeast KS and northwest MO.

Substantial wintry weather develops by Thursday evening in
northeast NE, with rain and a chance for thunder for east
central, southeast NE, and western Iowa. Isentropic lift on the
295K surface suggests 3 to 6 g/kg of moisture feeding into
northeast NE, which would suggest at least 6 to 12 inches of storm
total snow possible in that area. The rain/snow line may not even
make it to the I80 corridor until early Friday morning, but then
spreading across the remainder of the forecast area during the
morning.

There is some concern of the exact track of this storm, with
various models showing slightly different paths. The Nam was
generally discounted for being too far north, although the 18z
Nam began trending a little further south. Generally used a
consensus of other available models.

There is also a high degree of concern that because of the strong
wind gusts at or above 35 mph by late Thursday night into Friday,
we could be potentially be near or at blizzard criteria in
northeast NE. For this reason, the existing winter storm watch was
converted to a blizzard watch for portions of SD and northern IA.

Regarding headlines in our area, we have decided to upgrade the
existing winter storm watch currently in effect to a winter storm
warning, which begins at 6 pm Thursday. This includes the area
Albion to Norfolk to Wayne and areas northwest, given confidence
of heavier snow and potential near blizzard conditions that will
eventually develop in that area. Have opted to issue winter storm
watches southeast of this area, which includes Columbus to
Fremont to Blair to Denison, with a staggered start time from 10
pm Thursday to 6 am Friday. In this area, we have upped the
snowfall to the 4-7" range, but this area will also experience
near blizzard conditions on Friday, thus the reasoning for the
watch. Farther south, along I80, we have just 1-2" forecast, and
just barely a dusting near the NE/KS/MO border area.

Impacts from this storm will eventually be high, with a significant
impact to travel expected Thursday night into Friday night, due
to the combination of heavy snow, high winds, blowing snow, and
eventually near blizzard conditions in some areas. We have also
extended headlines to linger into Friday evening as impacts will
still be ongoing as the storm system slowly pulls away.


Saturday should be dry with high pressure across the forecast area.

.LONG TERM...(Saturday night through Wednesday)
Issued at 241 PM CST Wed Feb 22 2017

Didn`t have a lot of time to spend on the extended portion of the
forecast. There is another quick moving front that could bring a
slight chance of rain/snow to parts of the area Sunday. Another
weather system could bring rain/snow Monday night into Tuesday and
then dry for Wednesday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1111 AM CST Wed Feb 22 2017

Deteriorating conditions are expected at all terminals late
tonight with the approach of a strong storm system moving into
the central Plains. Increasing low level moisture will result in
widespread MVFR cigs advancing southward out of SD and into nern
Neb shortly after midnight...then expand over the rest of ern Neb
Thursday morning.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Watch from Friday morning through Friday evening
     for NEZ034-044-045.

     Winter Storm Watch from Thursday evening through Friday evening
     for NEZ015-032-033-042-043.

     Winter Storm Warning from 6 PM Thursday to midnight CST Friday
     night for NEZ011-012-016>018-030-031.

IA...Winter Storm Watch from Friday morning through Friday evening
     for IAZ043-055.

&&

$$

SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...DEE


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