Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 221121

Area Forecast Discussion
National Weather Service Omaha/Valley NE
621 AM CDT Mon May 22 2017

.SHORT TERM...(Today through Wednesday)
Issued at 308 AM CDT Mon May 22 2017

WV imagery this morning showing large upper level low pressure
currently centered in the vicinity of the western Great Lakes.
Imagery was also revealing very subtle impulses riding down the
backside of the system into the northern Plains.

Height falls associated with large upper level low pressure will
spread across the northern/central Plains today. Aforementioned
impulses will aid in inducing precip along a relatively weak cold
front making a southward dash through the Dakotas. HRRR/RAP13 are in
general agreement precip should be making its way into the northern
CWA by early afternoon.

Meanwhile...a second area of convection is progged to expand along
an axis of increasing 300-305k isentropic upglide this morning along
the Neb/KS border then into northern MO this afternoon. Given
overall environmental moisture...PWS1.25"...will be more plentiful
over the southern CWA through the day...highest amounts will be
found over the southern CWA. Tonight...focus for mid layer
ageostrophic lift will be found south of the I-80
corridor...allowing for possible generous rainfall amounts overnight
before the cold front pushes south of the CWA.

On Tuesday...upper low/vort max digs down through the upper Midwest
into the Mid MS Valley region. Models are in rather good agreement
pockets of isentropic upglide may induce post-frontal precip...more
or less isolated in nature...mainly during the afternoon hours.

Dry then Tuesday night through Wednesday night.

.LONG TERM...(Wednesday night through Sunday)
Issued at 308 AM CDT Mon May 22 2017

Precip chances in the extended periods come Thursday night/Friday
morning as well as the majority of next weekend...all in part to a
potent Pacific NW wave moving into the central Plains. Instability
parameters at this point look weak at best...thus reasonable to
assume severe storm potential will be minimal at best.


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 615 AM CDT Mon May 22 2017

Scattered showers and thunderstorms are forecast to develop near
TAF sites between 18Z and 22Z along a cold front moving into
eastern Nebraska. Coverage of storms will be little more than
isolated, to have maintained VFR conditions in TAFs. However there
will be MVFR cigs/vsbys under storms, so this could affect sites.
Otherwise generally southwest winds ahead of and northwest winds
behind the cold front will average about 10kt. But gusts to 25kt
are possible near precipitation.




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