Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 171735
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1235 PM CDT Wed May 17 2017

.SHORT TERM...(Today through Saturday) Issued at 324 AM CDT Wed
May 17 2017

Forecast concerns during the short term will be timing and
location of showers and thunderstorms today and potential for
severe storms/additional rain amounts and more showers and
thunderstorms Thursday night into Friday.

Ongoing showers and thunderstorms early this morning should
lift north toward the SD border with a break as The closed low
pressure system over southeast CO/northeast NM/OK Panhandle tracks
into the region. Additional showers and thunderstorms are
expected to develop along with a chance for severe storms and
additional locally heavy rains.

The latest surface map has a front in eastern Nebraska to western
Kansas and surface low pressure moves northeast along the front
into eastern Nebraska this afternoon. The belt of stronger winds
aloft extends from OK northward into eastern Neb. 50-70m ht falls
were noted ahead of the h5 trough over CO. The shortrange models
all deepen this compact h5 low over southeast Neb/northern KS at
18Z...lifting it northward toward SUX by 00Z. The ribbon of 1 to
1.5 inches pwat is in place this morning remains high around 1 to
1.25 inches through 00Z then begins decreasing. Forecast sounding
show modest instability of 1000-2000j/kg mainly through 21Z and
bulk shear of 20 to 45kts. The pattern for low topped supercells
is more favorable to the east of our forecast area...however our
wind pattern and modest instability do point toward at least a
marginal to slight risk of strong to severe storms later this
morning through mid afternoon...with an enhanced risk over Iowa.
Due to the track of the closed low...all modes of severe weather
will be possible...although it should be more isolated than
Tuesday. Northeast Nebraska is in the slight risk for excessive
rainfall...where some 1 to 1.5 inch rains may fall especially
through 21Z.  Tonight the h5 low will be exiting the area.

Later tonight and most of Thursday should be dry. The next storm
system is already moving in for Thursday and and lasts into the
weekend. Instability is more limited...however there is strong
upper level jet support, mid-level frontogenesis and mid level
omega to support widespread/locally heavy rains into Saturday.

.LONG TERM...(Saturday night through Tuesday) Issued at 324 AM
CDT Wed May 17 2017

Dry weather is forecast for Sunday however a shortwave in the
northwest flow brings wet weather into forecast for the rest of
the extended.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1233 PM CDT Wed May 17 2017

A deep-layer cyclone will track across the area this afternoon
into evening supporting the development of numerous thunderstorms,
some of which will be severe. Ongoing strong storms near KOFK
should continue north over the next hour with strong to severe
storms affecting KLNK and KOMA in the 18-22z time frame. By this
evening, convection should rapidly move to the northeast of the
area with winds shifting to the northwest.

&&

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

$$

SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Mead



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