Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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616
FXUS63 KOAX 270850
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
350 AM CDT Thu Jul 27 2017

.SHORT TERM...(Today through Saturday)
Issued at 330 AM CDT Thu Jul 27 2017

...Cooler Weather for the Next Several Days...

Forecast concerns will be early morning fog then cooler
temperatures and spotty thunderstorm chances.

Wednesday was a challenging forecast day with multiple rounds of
precipitation and the clouds hanging on keeping the temperatures
down for much of the area. Through 7am Wednesday...rainfall
varied from 0.01 in the Ashland area to 1.06" at nearby Gretna. In
general, the early morning rains were heaviest in northeast
Nebraska where 2.35 inches was recorded near Lyons in Cuming Co.,
however a north to south line of efficient rain producing
thunderstorms developed with 1.68 inches in Johnson Co. and other
1 inch amounts northward for parts of Sarpy and Douglas Co.
Additional locally heavy rains occurred during the day and these
amounts will be reported Thursday morning, however some early
storm totals include 5 inches that fell near Columbus and 3.2
inches at North Bend. Lincoln had a third of an inch with the
morning round, but picked up 2.5 inches more during the with a
storm total of 2.83 inches. Other storm totals included 0.57 at
Omaha Eppley, 1.23 inches at Norfolk, and 1.64 inches at Gretna.
The flash flooding set up just south of our area in parts of
Kansas and Missouri

Overnight, patchy dense fog developed with the clearing
skies...wet ground and residual high dewpoints. At 08Z...the drier
dewpoints had made it to KOFK with 60...however dewpoints were
still near 70 at KOMA. The h9 winds are forecast to increase
through 12Z...so this should help keep the dense fog at bay save
for perhaps in southwest Iowa were it may fill in. Will mention some
patchy fog in southeast Nebraska and southwest Iowa along with
some stratus.

The PWAT on the 00Z OAX sounding was 1.97 inches and is forecast
to drop to around 1.39 by 12Z and 1.10 by 00Z. After some variable morning
stratus, patchy cu may develop and there may be some isolated
showers try to develop toward Falls City. Due to low confidence,
do not have a mention in the current forecast.

Troughing deepens over the Great Lakes while the ridge builds to
the west...however a shortwave does impact parts of the Plains
Friday and Saturday. For now, the storms are expected to remain
mainly west of the forecast area.

Cooler high temperatures in the 80s can be expected with lows in
the upper 50s to lower 60s.

.LONG TERM...(Saturday night through Wednesday)
Issued at 330 AM CDT Thu Jul 27 2017

Sunday...surface high pressure is forecast over the Great Lakes
with the mid tropospheric ridge over the Rockies. In-between, we
are in northwest flow aloft with a shortwave tracking through
Plains. Thunderstorms are forecast to be ongoing at the start of
the period...possibly holding together as they drop southeast
across parts of the forecast area. The 00Z GFS is a bit stronger
with this feature compared to the 12Z/00Z dry EC...thus some pops
included in collaborative fcst.

Monday -Tuesday are dry with the focus for  storms just to are west,
however pops may be added if these hold together longer than
expected.  The medium-range models handle the timing and strength of
the shortwave traversing Canada a little differently.  Both the
GFS/EC increase the chance for thunderstorms Tuesday night-Wednesday
night especially in northeast Nebraska and depending on the frontal
position.  Again, the EC is mostly dry.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1149 PM CDT Wed Jul 26 2017

Visibilities will lower overnight as cloud cover shifts south.
IFR visibilities will be possible at both KOMA and KLNK through
12Z. Drier air to the north should maintain VFR conditions at
KOFK through the period. VFR conditions are anticipated at all
sites by late Thursday morning through the remainder of the
period.


&&

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

$$

SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...KG



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