Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 241116
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
616 AM CDT Sun Jun 24 2018

.SHORT TERM...(Today through Tuesday)
Issued at 315 AM CDT Sun Jun 24 2018

Main concerns are timing, location and intensity of storms the
next 36 hours and potential for heavy rain.

Isolated storms yesterday afternoon and evening were a bit more
intense that I thought. Some large hail was reported. Storms had
been bubbling early this morning, but isolated so far. General
trend has been for warming cloud tops over our area the past few
hours. Overall forecast confidence is not high, but there is some
risk of severe storms and rain amounts could reach over 2 inches
at some spots today/tonight.

The main feature in the large scale pattern is a closed low back
over WY that is well depicted in water vapor satellite imagery
early this morning. That feature should move out into the western
parts of SD and NE later today putting our area in stronger
diffluent flow aloft, which will continue into tonight as the
system stays to our west. The atmosphere will destabilize with
afternoon heating and boundary layer CAPE values could approach
2500 J/kg. This will occur with 0-6 km bulk shear of 20 to 50
knots and precipitable water (PW) values of 1.5 to 2.0 inches.
Models, particularly the 00Z GFS, increase PW to over 2.0 inches
in parts of southeast NE tonight. Although the convection allowing
model guidance and the parameterized models are not in excellent
agreement, felt the scenario of scattered storms becoming strong
to severe near the occluded front pushing into our area from the
west later today seemed reasonable. Some storms possible this
morning in northeast NE but coverage should be higher this
afternoon and evening with a higher chance of severe storms.
Strongest storms may shift more to southeast SD and western IA by
late tonight. Severe storms possible again Monday, but mainly in
our IA counties. Look for highs today mainly from around 80 to the
mid 80s and lows tonight from 63 to 68.

Monday, severe storm chances will ramp up again in the afternoon
as temperatures warm to the upper 70s and lower 80s. Heaviest rain
though is expected to be north and or east of our area Monday and
Monday night. Rain chances will generally be decreasing Tuesday
with more sunshine. The result should be highs in the lower and
mid 80s for the northern part of the forecast area and highs from
85 to around 90 south.

.LONG TERM...(Tuesday night through Saturday)
Issued at 315 AM CDT Sun Jun 24 2018

Longer range models are in pretty good agreement with the 500 mb
pattern mid to late week and also agree that the pattern for those
days should not be as wet. Temperatures should turn very warm/hot
again with highs from around 90 to the mid 90s. The flow in our
area become fairly zonal Wednesday but then turns to the southwest
as a trough advances in the Rocky mountain region Friday and a
ridge builds from the Gulf of Mexico into the OH valley. The
northern and central parts of the forecast area are currently
expected to be just slightly cooler for the weekend, and storms
will be possible for much of the area.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 610 AM CDT Sun Jun 24 2018

Confidence remains low in aviation forecast for this period. A few
scattered showers and thunderstorms could develop over northeast
Nebraska this morning, otherwise expect thunderstorms chances to
increase at all 3 TAF sites this afternoon. Generally, VFR
conditions are expected outside of any potential thunderstorm
activity this morning, before MVFR or lower cigs fill in across
the area tonight.

&&

.HYDROLOGY...
Issued at 315 AM CDT Sun Jun 24 2018

Main hydrology concerns are with the elevated stages of the
Missouri River, especially from Plattsmouth downstream. As the
water from high flows in southeast SD and northwest IA work into
the system, we should get a better idea of what crests will be
around Blair and Omaha. We will also be monitoring other streams
for potentially high flows, because of heavy rain potential.

&&

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

$$

SHORT TERM...Miller
LONG TERM...Miller
AVIATION...KG
HYDROLOGY...Miller



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