Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 262310
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
610 PM CDT Fri May 26 2017

.SHORT TERM...(Tonight through Monday)
Issued at 245 PM CDT Fri May 26 2017

The main forecast problems are in regards to thunderstorm chances
from late tonight through Saturday evening, along with potential
for severe storms.

Water vapor satellite imagery showed the weak feature that moved
through the area last night and early this morning was moving into
northern Illinois early this afternoon. Meanwhile, of more concern
is a closed low over eastern Idaho, which is embedded in a trough
that extended from Saskatchewan and Manitoba down into Nevada.
That low should become more of an open wave overnight, then that
will move eastward through the local area Saturday night. Forcing
is expected to be strongest in our area during the day Saturday.

Storms that initially develop out over the High Plains this
afternoon will move eastward overnight. Latest consensus from the
convection allowing models (CAMs) is that precipitation will
stay west of our area through 1 am cdt tonight, but may start to
approach Highway 81 by 4 am cdt, and may affect the western half
of the forecast area by 7-8 am cdt. Focus of the low level jet
stays well to the west, so the chance of severe storms overnight
looks low.

Severe threat on Saturday will be higher to our south/southeast
across Missouri, but we could see some strong to severe storms in
southeast Nebraska and parts of southwest Iowa. 0-6 km bulk shear
values are 30-50 knots and MU CAPE values are 2000-3500 J/KG much
of the afternoon. Will mention some severe storms possible in the
HWO. It looks like some showers/weaker thunderstorms may linger
into the mid or possibly late evening, then end by midnight. That
then sets us up for a mainly dry forecast (at least for now) for
the Sunday and Monday periods. Temperatures should be cooler on
Saturday, compared to today, ranging from mid to upper 60s in
northeast Nebraska to mid and upper 70s near the Missouri and
Kansas borders. Highs Sunday and Monday should reach the 70s.

.LONG TERM...(Monday night through Friday)
Issued at 245 PM CDT Fri May 26 2017

The 500 mb pattern will be quite amplified at the start of the
period, with a ridge over the western parts of the CONUS and
Canada. A closed low will be over or just north of Lake Superior
and our area should be in modest to strong northwest flow. This
should dampen out during the week, while a closed low tracks from
the Pacific into the four corners region. Rain chances in our area
look highest from Wednesday night into Thursday, but confidence on
timing of showers and storms next week is only moderate.

Highs will be mostly in the 70s, with lows from the upper 40s to
upper 50s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 610 PM CDT Fri May 26 2017

Thunderstorms currently developing over the central High Plains
will advance east into the lower MO Valley late tonight into
Saturday morning, aided by warm advection and moisture flux along
a nocturnally enhanced low-level jet. Additional storm development
will be possible Saturday afternoon across parts of southeast
into east-central NE. As such, have included a mention of VCTS at
all three TAF sites and continue it into Saturday afternoon at
KOMA and KLNK. Will only include VFR ceilings with the convective
activity at this juncture.

&&

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

$$

SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Mead



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