Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 170809

Area Forecast Discussion
National Weather Service Omaha/Valley NE
309 AM CDT Mon Jul 17 2017

.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT Mon Jul 17 2017

Hot weather will continue, along with a chance of showers and storms
later today and tonight. Subjective 00Z upper-air analysis indicates
upper-level ridge dominating the central US, with troughing over the
eastern Great Lakes/mid-Atlantic and also in western Canada.
Temperatures at 850mb were well into the 20s C across the central
Plains to northern Rockies to CA coast. Abundant moisture also was
noted, with 12 C+ dewpoints across the central Plains. Surface low
at 07Z was near the MB-SK border, with trough axis through western
ND and western SD into the NE-WY border area. Pockets of storms were
noted in north central ND and near the KS-CO border.

Main forecast concerns include heat and convective potential. With
20C+ temperatures at 850mb continuing today, temperatures again will
rise into the 90s. A weak upper-level shortwave trough (currently
associated with KS-CO convection) should slide through NE
today/tonight. Airmass will remain capped through most of the day,
with convection likely limited to area very near the trough, and
thus have slowed its timing into the CWA until after 00Z. Think
isolated to scattered coverage seems appropriate for the convection
tonight, with POPs in the slight chance to chance categories.

Potential for temperatures well into the 90s continues on Tuesday,
but confidence is a bit shakier, given the possibility of clouds or
showers lingering into Tuesday morning. Current grids brush heat
advisory criteria in central to southeast NE, but given low
confidence, will hold off issuing any headlines. The cold front
currently well north in the Dakotas will sag southward slowly,
potentially making it to northeast NE/northwest IA by around 00Z
Wednesday. The front will bring the potential for storms through
Tuesday evening and into Tuesday night as it sags southward.  Given
MLCAPE around 3000+ J/kg and at least some deep-layer shear (around
30-40kt), strong to severe storms could develop, especially in the
late afternoon to early evening.

Front is progged to return northward rather quickly on Wednesday,
with temperatures in the 90s to near 100 once again. The hottest
temperatures are indicated in south central to southeast NE, with
optimized mixing and earliest return of southerly winds. Again, if
convection hasn`t muddied the temperature potential, advisory-
criteria heat indices would be possible, mainly along and south of I-

.LONG TERM...(Wednesday night through Sunday)
Issued at 307 AM CDT Mon Jul 17 2017

The weather story won`t change much through Saturday, with hot
temperatures (especially in the southern half of the area) and
potential for occasional storms (especially in the northern half of
the area) under the influence of upper-level ridging and ridge-rider
shortwave troughs. An upper-level trough is progged to slide into
the Great Lakes this weekend, driving the upper-level ridge westward
and providing some relief to the temperatures. It also may drive a
front through the area, with attendant convective potential, perhaps
on Saturday. Temperatures should return to more seasonably normal or
even below-normal readings by Sunday.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1127 PM CDT Sun Jul 16 2017

VFR conditions are forecast through Monday night with scattered
high clouds and south winds mainly near or under 12kt. However
there is a small chance isolated thunderstorms could develop to
the west of and move into the KOFK area between 00Z and 06Z.




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