Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 210846
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
346 AM CDT Sat Sep 21 2019

.SHORT TERM...(Today through Monday)
Issued at 333 AM CDT Sat Sep 21 2019

At 333 AM, a thick blanket of low clouds was draped over the
region. Areas of light drizzle were being reported along the
Missouri River Valley (including here at the office), with
accumulations limited to just a trace of precip. Southerly winds
remained breezy, with frequent gusts into the low 20s.
Temperatures were in the lower 70s, and probably won`t drop
appreciably prior to sunrise given the low cloud cover.

Strong southerly flow will continue this morning ahead of an
approaching upper level trough and surface front. Within the
southerly flow, forecast soundings suggest a deep saturated to
near saturated layer below a strong inversion at 5000 ft. This
suggests the continuation of the thick low cloud layer (>3000 ft
thick) through midday and could allow some patch drizzle to stick
with us through 10 AM or so. Any drizzle accumulations should be
limited to just a trace or a couple hundredths.

The main show today should occur this evening, and consist of
strong to severe thunderstorms developing along a frontal boundary
in southeast Nebraska and southwest Iowa between 5 PM and 9 PM.
Avid AFD readers may note that the time window for storm
initiation has been moved up by about 4 hours compared to the
forecast 24 hours ago. The primary reason for the adjustment is
the earlier erosion of the capping inversion (near 750 mb) in the
CAMs. Sounding profiles suggest hail as the primary threat this
evening (ping pong ball or larger hail possible), with a lower
risk for damaging winds. A brief tornado or two are also possible
between 5 PM and 9 PM, before storms grow upscale into and MCS.
Heavy rain and flash flooding remain a concern this evening and
overnight, and the Flash Flood Watch is still place for Gage,
Johnson, Pawnee, Nemaha, Richardson, Otoe, Fremont and Page
Counties. However, with 1 to 3 hour flash flood guidance hovering
near 2-3 inches in southern Nebraska and Iowa, it seems like the
greatest risk of flooding will be to our south over northern
Kansas and Missouri. Widespread rainfall totals of a half inch or
more are possible south of Interstate 80 through Sunday morning,
while localized 3 plus inch amounts are possible near the KS/NE
and IA/MO borders.

The region will dry out Sunday as the upper level trough axis
shifts east and surface high pressure settles in. This should
bring more sunshine to the region Sunday afternoon, and limit
afternoon highs to the lower/mid 70s. Winds will be light and
variable. Looks like a really nice end to the weekend!

Fair weather will stick with us Monday as a weak upper level
ridge builds overhead, and the surface high drifts southeast into
Missouri. The one notable change should be the return of
southerly winds in the 8 to 14 mph range. High temps will likely
top out near 80 degrees.

.LONG TERM...(Tuesday through Friday)
Issued at 333 AM CDT Sat Sep 21 2019

Near zonal flow during the middle of next week, looks like it will
give way to a highly amplified longwave pattern over the U.S. by
next weekend (trough in the West & ridge in the East). Confidence
is high in the development of the pattern. The wildcard in the
forecast next week remains a cutoff low that is progged to lift
out of the Southwest into the Plains sometime between Thursday and
Saturday. This low could have fetch of tropical moisture with it,
and has the potential to produce another widespread rain event in
the Plains. Cutoffs are always such a fun pattern to deal with
;).

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1125 PM CDT Fri Sep 20 2019

Breezy southerly winds are expected to continue into Saturday
morning. Current MVFR ceilings will continue to decrease to IFR
early Saturday morning. Additionally, A few spotty showers may be
possible at OMA and LNK Saturday morning. Otherwise ceilings
should improve to VFR after sunrise. Chances for showers and
thunderstorms may be possible again late in the TAF period at OMA
and LNK but confidence is low, with higher chances remaining south
of the TAF sites, so it has been left out of this round of TAFs.


&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flash Flood Watch from this evening through Sunday morning for
     NEZ068-089>093.

IA...Flash Flood Watch from this evening through Sunday morning for
     IAZ090-091.

&&

$$

SHORT TERM...Albright
LONG TERM...Albright
AVIATION...HB


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