Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 182316

Area Forecast Discussion
National Weather Service Omaha/Valley NE
616 PM CDT Sun Mar 18 2018

.SHORT TERM...(Tonight through Wednesday)
Issued at 252 PM CDT Sun Mar 18 2018

Mid afternoon on Sunday featured the same persistent low stratus
deck across much of the forecast area that has been in place for
the past 36+ hrs. However, the southwest edge was eroding with the
GOES snow/ice RGB nicely showing some clearing southwest of a
Seward to Beatrice line under additional layers of mid and high
level clouds. Surface high pressure had shifted off to the east
over northern Illinois while surface low pressure was deepening in
southeast Colorado this afternoon. Convective cloud elements and a
few light reflectivity returns on radar were moving northeast out
of northern KS and central NE, seemingly in response to a push of
mid level moisture underneath a plume of steep lapse rates.
Additional convection was present from north central OK into
southeast OK. Water vapor imagery showed a strong short wave
trough digging east across the Four Corners region while another
lead short wave was crossing western Oklahoma. The OK system was
pulling moisture north into the Plains while the Four Corners
trough will not only help steer the OK energy toward southeast
Nebraska, but will be providing ample forcing for precipitation
over Kansas and into Nebraska/Iowa over the next 24 hours or so.

Through this evening, as the forcing approaches and mid level
moisture increases, expect coverage of convective showers to
increase across much of the area with a focus moreso over
southeast Nebraska. Forecast soundings (and current satellite
trends) suggest that weak instability currently in place will
increase through the evening hours over the southern half of the
area as that moisture profile deepens immediately under the steep
lapse rates. RAP/NAM soundings indicate 200-500 J/kg of MUCAPE and
have included thunder through the evening hours. Later tonight,
the northeastward surge of moisture is likely to wane and stall as
the main upper low crosses the Plains near the KS/OK border. This
storm track should actually work to pull dry air into the forecast
area from the northeast, and have tapered off to a dry forecast in
eastern parts of the forecast area by Monday afternoon.

A separate short wave trough on a more northern trajectory comes
into play by Monday afternoon through Tuesday as it very slowly
moves across the region. Ample moisture pulled from east to west
around the north side of the KS/OK storm system will interact with
weak to moderate forcing to develop a slow moving band of snow
and/or rain from late Monday into Tuesday. While precipitation is
likely, the main questions for the forecast at this point lie in
the quality of the moisture profile and the specifics of the
temperature profile. Currently have a trace to 2 inches of snow in
the forecast, but given the expected duration of the snow could
see a bit more than that especially in far northern parts of the
forecast area if temperatures are cool. This will be something to
watch. Any precipitation should end in eastern parts of the
forecast area by early Tuesday afternoon with a warming trend
through the remainder of the work week.

.LONG TERM...(Wednesday night through Sunday)
Issued at 252 PM CDT Sun Mar 18 2018

Wednesday and Thursday are expected to be mainly dry as an upper
level ridge gradually builds overhead. There is a consistent
signal for an area of rain to develop near/northeast of the area
Thursday night into Friday in response to warm advection and
moisture convergence. Then from Friday through the weekend the
weather pattern looks to remain active with the main question
being in the timing and track of multiple storm systems expected
to cross the Plains within the generally southwesterly upper flow
pattern every 48 hours or so. At this point, uncertainty is too
great in timing and track to indicate any specific hazards, but it
is worth mentioning that impactful weather will be possible
through the period in the local forecast area.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 614 PM CDT Sun Mar 18 2018

MVFR conditions at all TAF sites, but becoming IFR through the
night, and possibly LIFR at KOFK. A few showers affect the TAF
sites in the first half of the TAF period, and it could mix with
snow at KOFK 09-12z. Beyond then, dry easterly flow may limit
areal precipitation coverage, and opted to leave out of the TAFs
at this time.




SHORT TERM...Barjenbruch
LONG TERM...Barjenbruch
AVIATION...DeWald is the U.S. government's official web portal to all federal, state and local government web resources and services.