Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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773
FXUS63 KOAX 212313
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
613 PM CDT Sat Apr 21 2018

.SHORT TERM...(Tonight through Tuesday)
Issued at 300 PM CDT Sat Apr 21 2018

Warm conveyor belt associated with H5 low trekking across
Oklahoma, continues to advect transport mid- to high-level
moisture into the region. Main dynamic forcing remains to the
south of the forecast area, given semi-barotropic nature of
upper low. Isentropic and vorticity fields showing some enhanced
mid-level lift across southeast Nebraska until 02-03z, so will
maintain slight chance to low chance PoPs through that time.
Clouds and lack of significant cold advection in wake of upper
level system will keep temperatures from cooling much overnight,
and only adjusted current forecast slightly. For Sunday, expect
temperatures to warm into the 60s in most locations. H8 thermal
trough does not move east of forecast area until after peak
heating, and expansive mid- to high- level cloud shield in wake
of upper system, so trended toward the lower end of guidance. More
substantial warm-up expected for Monday, with less cloud cover
allowing for better mixing. Cirrus shield from next system to
impact the area looks to remain west of forecast area, thus do not
feel temperatures will be impacted. Speaking of next system,
forecast model suite has been consistent with timing and intensity
of compact shortwave dropping northwest across the Plains
Monday night into Tuesday. Ample low level moisture appears to be
in question, thus only chance PoPs seem appropriate. Clouds and
any precipitation will limit temperatures again, with going
forecast reasonable.

.LONG TERM...(Tuesday night through Saturday)
Issued at 300 PM CDT Sat Apr 21 2018

Previously mention compact short wave, syncs/amplifies eastern
U.S. trough. Several shortwaves will traverse periphery of large
scale trough, providing the area with another slight chance of
precipitation Wednesday night into Thursday. Temperature profiles
appear to support a brief period of mixed precipitation in
northeast Nebraska in the wake of shortwave passage Wed night-
Thurs, with some overlap with deformation band associated with
upper system. The series of shortwave features traversing large
scale trough, will bring several reinforcing surges of a low level
cold advection through Friday. As such, kept temperatures cooler
than normal through then, with a rebound toward near normal
late April temperatures on Saturday as upper level ridging builds
into the area.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 612 PM CDT Sat Apr 21 2018

VFR conditions through the period, with a general northeasterly
wind direction less than 12 knots. Winds become southeast at KOFK
later in the period.

&&

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

$$

SHORT TERM...Fortin
LONG TERM...Fortin
AVIATION...DeWald



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