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Area forecast discussion 
National Weather Service Omaha/valley NE
542 PM CST Thursday Jan 29 2015

Short term...(tonight through sunday)
issued at 315 PM CST Thursday Jan 29 2015

Precipitation amounts and precipitation type will provide the main forecast challenges
in this period. Models have settled somewhat and now suggest at
least our southern counties could get some snow accumulation.

Tonight...surface ridge axis will build into the area with north
winds decreasing and even switching back to the south late tonight
in our western zones. Cloud cover was still rather extensive at 3 PM
along and east of Highway 81. Expect that we will continue to see a
decrease in cloudiness at least on the western edge. Latest runs of
the rap and NAM suggest some low clouds may linger based on 925 mb
relative humidity forecasts. If clouds can at least scatter out later
tonight as expected...we should see lows in the upper teens to
around 20 degrees.

Southerly winds will increase into the 10 to 20 miles per hour range with some
higher gusts on Friday. Winds may get into the 15 to 25 miles per hour range
in northeast Nebraska. Expect temperatures to top out in the 40s.

Moisture and clouds should increase Friday night. A cold front will
be sinking into our northern zones after midnight with some cooler
air there...but temperatures in the south should stay mostly near
or above freezing. Have increased probability of precipitation a bit for Friday night in
southeast Nebraska but it does not look like there would be any
snow accumulation in that period. Will need to closely follow the
southward progress of the colder air. If surface temperatures
can drop below freezing...there will be some potential for light
freezing rain.

Best dynamics will stay south of our area Saturday...but using a
combination of recent runs of the sref...GFS and European model (ecmwf) suggests
that at least parts of our area will see some snow accumulation.
The NAM forecast soundings seemed to cold and thus seemed to
produce too much snow. As the cold air deepens Saturday night and
darkness sets in...precipitation should trend toward all snow. A modest
area of upper level forcing should track over our area from the
northwest Saturday night. A mix of rain and snow may continue over
the southeast corner of Nebraska and in far southwest Iowa early
in the evening. Details on precipitation type will be critical for actual
snow accumulations and there is still plenty of uncertainty at
this time.

It appears that the primary lift will be exiting the area Sunday
afternoon...but held onto some slight chances in case the system
slows down a bit. Current thinking on potential snow amounts...
and the key word is potential...is for around 2 inches or more
along and southeast of a line from Lincoln to Omaha...possibly
approaching 3 to 4 inches near the Missouri border. These would be
total amounts for the whole event. Temperatures will turn colder
for Sunday with brisk north winds.

Long term...(sunday night through thursday)
issued at 315 PM CST Thursday Jan 29 2015

A brief and small warmup may occur Tuesday with highs in the 30s
north to lower 40s south...but in general this period will have
below normal temperatures. Look for highs mainly in the middle 20s to
middle 30s with lows in the single digits and teens. Have gone with
some small chances for light snow for parts of the area from
Monday night into Tuesday night...but best potential is during the
day Tuesday. Amounts would be an inch or less the way things look
right now.

&&

Aviation...(00z tafs for kofk...klnk and koma.)
Issued at 531 PM CST Thursday Jan 29 2015

MVFR/VFR low clouds are hugging the Missouri River and the rap
maintains this for several hours. This may be too pessimistic...so
will maintain scattered-broken fl035 at koma for a few hours this evening
and monitor the western edge of the clouds. Northwest winds will
continue to slacken to light and variable this evening.

&&

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

$$

Short term...Miller
long term...Miller
aviation...zapotocny

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