Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 222042

Area Forecast Discussion
National Weather Service Omaha/Valley NE
342 PM CDT SUN MAY 22 2016

.SHORT TERM...(tonight through Wednesday)
Issued at 330 PM CDT Sun May 22 2016

Latest water vapor imagery indicates a closed low over southern
Alberta with an amplified ridge to our east extending along the
Mississippi River Valley. In the lower levels...the 850mb moist
axis stretched north from western Texas into the western Dakotas
and continues to slowly shift east ahead of the main upper low.
18Z subjective surface analysis showed low pressure centered over
Colorado with large ridge of high pressure over the Mississippi
River valley. Surface dewpoints continue to increase over the area
with a broad area of 65+ extending across western/central Kansas
and lower 60s across all of central Nebraska. These lower to mid
60`s dewpoints will continue to spread northeast into the CWA by
Monday afternoon. In the meantime, a dryline was noted across the
High Plains with an additional weak surface boundary extending across
western Nebraska into south central South Dakota along which some
convection has initiated in north central Nebraska. With some
hesitation, will leave our evening forecast dry as any convection
to our west should drift northeast. We do introduce pops in the
overnight period...primarily after 06Z as vort max associated with
trailing upper trough sparks a convective complex over the Black
Hills region. This activity will likely be sustained by 40-50kt
southwesterly low level jet overhead. Convection will continue to
slide southeast along weak frontal boundary through the morning
and into the afternoon hours. This activity will most likely leave
a mess of outflow boundaries draped across the region where
convection could later focus.

A continued complex, lower confidence forecast continues Monday
night into Tuesday as a series of vort max`s moves through
southwesterly flow aloft. A surface warm front is progged to
extend east from the eastern Colorado surface low across northern
Kansas by Tuesday morning. The advancement of this boundary is
still somewhat uncertain but should be the focus for convection
into Wednesday. In any event...PW`s are are forecast to be
150-175% of normal so heavy rain is certainly a
possibility...especially across our southern counties in closer
proximity to the warm front. Our area has been outlooked in the
Slight Risk for excessive rainfall in addition to SPC`s Slight
Risk outlooks.

.LONG TERM...(Wednesday night through Sunday)
Issued at 330 PM CDT Sun May 22 2016

At the beginning of the period, modest southwesterly upper level
flow will continue over the Central Plains region ahead of an
upper low moving just to the south of the Great Basin. This
feature is forecast to open as it moves east into the Four Corners
providing continued southwest flow to the area. The shortwave
trough is progged to move across eastern Nebraska/western Iowa
sometime either Friday or Saturday. The 12z ECMWF has slowed this
feature down from previous runs. Model uncertainty increases
behind the above mentioned trough but overall mid/upper level
pattern remains southwesterly with unsettled weather continuing
into Memorial Day.


.AVIATION...(18Z TAFS for KOMA...KLNK...KOFK through 18Z Monday)
Issued at 1215 PM CDT Sun May 22 2016

Generally still expect VFR conditions into at least the evening.
MVFR ceilings possible tonight all three TAF locations...and IFR
ceilings possible at KOFK with thunderstorms. IFR visibilities
also possible in any thunderstorms.


.OAX Watches/Warnings/Advisories...


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