Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 231115

Area Forecast Discussion
National Weather Service Omaha/Valley NE
615 AM CDT Thu Mar 23 2017

.SHORT TERM...(Today through Saturday)
Issued at 402 AM CDT Thu Mar 23 2017

Latest water vapor imagery along with 00Z subjective 500 mb analysis
shows an upper level ridge axis extending over the nation`s mid-
section with a potent upper trough digging across the Great Basin.
At the surface, an associated lee-side low was centered over eastern
Colorado early this morning while a large area of high pressure
was moving east across the Ohio Valley keeping fairly dry
southeasterly flow over the CWA. 00z 850mb analysis showed strong
850mb warm/moist advection over much of the Central Plains.
An extensive stratus deck continues to spread north across
central Kansas and is forecast to continue to spread
north/northeast through central and eastern Nebraska/southwest
Iowa through early afternoon before scattering out mid to late
afternoon. Scattered showers or drizzle is possible in association
with strong isentropic upglide in low-mid level warm air
advection regime. As the clouds do scatter this afternoon,
temperatures in our southern CWA should be able to reach the
lower 70`s which is a few degrees above guidance. Across areas in
our north, did leave temps in the lower 60s where clouds will
stick around through peak heating.

By 00z tonight, the Great Basin low is forecast to close off and
move across southern Colorado with the surface cyclone quickly
deepening over eastern Colorado. Ahead of this, a strengthening
southerly low-level jet is forecast to increase to around 50-70kts
across much of the Central Plains. Steep mid-level lapse rates
will spread across western and central Nebraska late this
afternoon as the system slides into southeastern Colorado. Despite
a lack of rich low-level moisture, convection could develop along
strong low-level convergence zone along the frontal boundary
extending from sfc low northeast across central and northeastern
Nebraska. Latest runs of the HRRR and RAP are beginning to pick up
on this as well. SPC Day1 includes a Slight Risk over northeast
Nebraska which seems reasonable for big hail into late evening.

Scattered showers and thunderstorms will continue overnight along
and behind the frontal boundary as it drifts south through the
northern CWA into Friday morning. Some scattered activity still
possible in the warm sector within strong isentropic upglide
region. Showers become more likely through the day Friday as the
upper circulation drifts east across Kansas with the surface low
hugging the Kansas/Oklahoma border. Higher QPF values will remain
in bands across our northern CWA with temperatures profiles
indicating all rain.

A break in activity is expected by later Saturday morning as the
system moves southeast into Missouri and weak shortwave ridging
builds overhead.

.LONG TERM...(Saturday night through Wednesday)
Issued at 402 AM CDT Thu Mar 23 2017

A shortwave trough will slide over the Colorado Rockies and swing
into western Kansas by Sunday afternoon with another surface low
hugging the Kansas/Oklahoma border. This will bring best chances
to our southern CWA into Monday afternoon.

Shortwave ridging will build overhead behind this system with a
deepening trough over the southwestern CONUS by the end of the
period. Model uncertainty remains with the ECMWF bringing this
system into Kansas whereas the GFS keeps the system across central


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 615 AM CDT Thu Mar 23 2017

Low level moisture will be on the increase this morning, with
ceilings dropping into the MVFR category. There may be a period
of IFR ceilings as some patchy light precipitation. Chances are
generally too low to mention in TAFs at this time. Winds around
2000 feet agl will be fairly strong through the period, so there
will be some low level wind shear.




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