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Area forecast discussion 
National Weather Service Omaha/valley NE
1132 PM CDT Friday Aug 22 2014

Short term...(tonight through monday)
issued at 310 PM CDT Friday Aug 22 2014

The chance for thunderstorms and temperatures will provide the main forecast
challenges in this period.

Upper air charts from 12z showed the following. Main jet segments at
300 mb were noted punching southward along the Pacific northwest
coast (110 knots) over northeast New Mexico (65 knots) ahead of the
closed low over Arizona...and from Michigan southeastward to the middle
Atlantic (70 knots). At 500 mb closed lows were located in southern
Washington state and in central Arizona. These were embedded in a
longwave trough that covered the western United States. Ridges were
in the eastern Pacific and from the Gulf of Mexico coast up into
the western Great Lakes region. Ample moisture was in place across
the Central Plains. Precipitable water from the 12z sounding at
koax was 2.00 inches...700 mb dewpoint was 8 degrees celsius and
the k index was 40.

Scattered storms have been bubbling much of the day in northeast
Kansas and parts of southeast Nebraska. Some storms had recently
developed north of Omaha. The general consensus of the short range
models suggests that current storms in the area will tend to diminish
this evening. New storms are expected to develop with the low
level jet and weak large scale forcing moving eastward from the
High Plains. This would be generally along or north of the 850 mb
warm front. Since the high precipitable water values are forecast
to remain in place....warm cloud depth is pretty deep (mostly
11000 to 13000 feet) and cape profiles should still be favorable...
expect areas of locally heavy rain. Most likely spot for this to
setup is across the northern zones. Will keep highest probability of precipitation there
overnight. Look for lows around or a few degrees above 70 at most
locations.

For Saturday...best large scale forcing for upward vertical motion
will be tracking east/northeast across the northern plains north of
our area. Will hold onto some low probability of precipitation north with boundary possibly
lingering there...especially in the morning. Highs should reach
the lower and middle 90s south and upper 80s or near 90 north.

A weak cold front will push into our area from the west Saturday
night but forcing and low level convergence are not impressive.
Decided to keep some slight chance of thunderstorms going...based on a blend
of available model solutions but amounts if any should be light.

Sunday through Monday...pattern is not overly favorable for precipitation in
our area as a closed low at 500 mb will track from the western
Dakotas into southwest Ontario. Heights build a little as the middle
tropospheric anticylone strengthens over the Missouri/Illinois/
Kentucky border region. Highs Sunday should range from 80s north
to 90s south. Look for minor cooling Monday behind a cold front.

Long term...(monday night through friday)
issued at 310 PM CDT Friday Aug 22 2014

Models are in pretty good agreement that the trough axis at 500 mb
over The Rockies Monday will move east to our area by middle week and
then move mainly east of US by late week. Thus expect temperatures
to be near normal at the beginning of the period...but then decrease
a bit. Best rain chances will be from Monday night through Tuesday
night with shortwave energy aloft moving over the area from the
southwest. This will be north of a slow moving frontal boundary over
Kansas and Missouri.

&&

Aviation...(06z tafs for kofk...klnk and koma.)
Issued at 1130 PM CDT Friday Aug 22 2014

A strengthening low level jet in response to shortwave energy
lifting out of an upper trough to our west will bring scattered
thunderstorms to eastern nebr tonight and activity should impact kofk
the longest. Although gusts over 40kts have been observed with
initial line moving northeast...earlier convection in the kofk
vicinity could have provided enough low level stabilization to
keep wind gusts a little below that threshold there...and the same
case could be made for koma. Later tonight MVFR ceilings...or possibly
lower...especially at kofk...should develop in response to areas
of heavy rain. Fog is also a decent bet toward morning as/if
shower activity would spread north of area...and MVFR mention was made
with visibilities as well. Some thunderstorm risk could linger into
Saturday in northestern nebr and additional storms should develop west of
the region Sat aftn/evening. But for now mention was left out of
taf sites as activity into Saturday afternoon was uncertain at kofk and
impact of any development over High Plains would probably be late
in the period.

&&

Oax watches/warnings/advisories...
NE...none.
Iowa...none.
&&

$$

Short term...Miller
long term...Miller
aviation...chermok

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