Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 200358

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1058 PM CDT Wed Oct 19 2016

.SHORT TERM...(tonight through Saturday)
Issued at 307 PM CDT Wed Oct 19 2016

Early-afternoon water vapor imagery revealed a low-amplitude
short-wave trough over the northern and central High Plains with
this feature expected to intensify over the next 24 hours as it
translates east through the mid Missouri Valley. In the low
levels, a cold front analyzed from central Iowa through east-
central Nebraska into northwest Kansas as of 18z will advance
south into the Ozarks by 12z/Thursday.

Forcing for ascent/height falls on the leading edge of the High
Plains trough has fostered a shield of mainly light convective
precipitation as of midday from portions of southeast South Dakota
into central and western Nebraska. Latest short-term convection-
allowing model guidance suggests that the best chance of
measurable precipitation will exist over the southern half of the
forecast area tonight, coincident with the strongest DCVA
attendant to the amplifying mid-level trough. While an isolated
thunderstorm is possible, it appears that instability will remain
quite limited with mainly showers expected.

After a cooler day on Thursday, mid-level heights will build over
the Great Plains with downslope warming in the low levels
promoting gradually warmer temperatures into this weekend.

.LONG TERM...(Saturday night through Wednesday)
Issued at 307 PM CDT Wed Oct 19 2016

By early next week, 12z medium-range guidance is in relatively
good agreement in suggesting that the next longer-wavelength
trough will begin to move onto the Pacific Coast. However, in the
Monday to Wednesday time frame, spread in model solutions grows
considerably. The ECMWF suggests that a substantial portion of the
Pacific Coast trough will move through the Interior West into the
Great Plains by midweek, driving a deepening surface cyclone over
the central Plains. In contrast, the GFS and GEFS mean solutions
maintain west-southwest flow across the Rockies into the central
Plains with a series of weak perturbations moving through this
flow regime. In either scenario, southerly low-level winds should
aid in the poleward transport of an increasingly moist air mass
into the region, supporting a chance of showers and thunderstorms
Tuesday and Wednesday. This pattern will also promote above normal


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1055 PM CDT Wed Oct 19 2016

A line of showers will bring a brief and very light shower to
KOMA, with a more moderate shower at KLNK, into the first hour or
so of the TAF cycle. Guidance suggests that showers further west
will dissipate before reaching eastern NE, and will thus limit
shower mention to just this line in the early hours. Otherwise,
mid-level ceilings are likely through the rest of the night, with
potential for a couple of hours of restricted visibility at KOFK
if they can clear out. Have kept KOMA/KLNK unrestricted, expecting
longer-lasting cloud cover, but they could also dip visibility if
they have a few hours of clearing. VFR conditions will follow from
the morning onward, with light north winds.




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