Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 201944
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
244 PM CDT Wed Sep 20 2017

.SHORT TERM...(Tonight through Saturday)
Issued at 222 PM CDT Wed Sep 20 2017

Cold front at 18z had pushed just south of the area, and was
defined very well by a wind shift and an associated cloud street
field from northeast KS through northeast IA. ESRL HRRR/Operational
HRRR/RAP all keep convection just east and southeast of the
forecast area initially this evening, but develop some additional
convection along the stalled boundary by 06z which could clip
extreme southeast NE and southwest IA overnight.

The stalled front then begins to lift back as a warm front by
daybreak Thursday. This could result in isolated thunderstorms for
a few hours early Thursday, but then the threat diminishes as the
front essentially washes out and diurnal effects of low level jet
are diminished. This sets us up for a hot, humid and breezy
afternoon with daytime highs climbing back into the mid 80s to
lower 90s across the region, and dewpoints again back into the
upper 60s to lower 70s.

Quite warm and muggy conditions persist Thursday night with lows
only in the lower to mid 70s. The GFS wants to develop convection
on the nose of a 40-50 knot low level jet, as does the SREF, but
the Nam, ECMWF, and High-res ARW/NMM models all remain dry.

Friday is another hot, humid, and windy day. Afternoon highs again
reach the upper 80s to lower 90s, dewpoints again near 70, and
southerly winds again in the 20-30 mph range.

A cold front will be moving into extreme northeast NE by late
Friday afternoon, in response to a pretty sharp trough to our
west. This will result in a chance of thunderstorms in that area,
which will have an associated severe weather risk into Friday
night.

The cold front makes slow progress southward into the area on
Saturday, although models differ slightly on how far south to take
it. Best chance for precip Saturday will be north of I80, with
remainder of the area warm and dry with highs again in the upper
80s ahead of the front.

.LONG TERM...(Saturday night through Wednesday)
Issued at 222 PM CDT Wed Sep 20 2017

High 60-80% pops along/north of the front are in the forecast
through the weekend, with precip eventually working into
remainder of the area Sunday night into Monday, and finally east
of the area by Tuesday evening. Northwest half of the forecast
area could see locally heavy rainfall and would not be surprised
to see up to a couple of inches over a 48 hour period for
portions of central through northeast NE. Thus not expecting any
widespread flooding, but a soggy weekend nonetheless for some
locations. Temps progressively get lower Sunday through Tuesday.
Dry conditions then for Wednesday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1230 PM CDT Wed Sep 20 2017

In general VFR conditions are expected during this TAF period. A
weak weather system will move through overnight. This could lead
to some low cloud formation at KOMA, though confidence is low in
this happening.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...Pearson



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