Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Omaha/valley NE
535 PM CST sun Nov 23 2014
Short term...(tonight through wednesday)
issued at 249 PM CST sun Nov 23 2014
Cold front is bringing gusty winds and light rain to the area.
Subjective 12z upper air analysis indicates 500mb trough digging
into The Rockies/plains...with 145kt jet streak extending from or/Washington
into Nevada behind the trough. 850mb cold front extended from low in
southern mb/northern ND/northern Minnesota through eastern Nebraska/central
Kansas/western OK...with 4c+ dewpoints in place ahead of it across the
Midwest/Great Lakes. Cold air advection was filling in behind the
front...though with 850mb temperatures in the single digits below normal as
far north as central ab...cool-down is not as significant as earlier
this month. Surface low at 20z was centered in east-central
OK...with cold front extending from secondary low in western ont
through eastern Minnesota/central Iowa/northwestern MO...and with a tight
pressure gradient behind the front across the plains.
Main forecast concerns are variable temperatures and intermittent
chances for light precipitation. Tonight...breezy northwest winds
will continue...with stratocu deck sliding into the northern County Warning Area.
May see a few flurries under these clouds late tonight into Monday
morning...with upstream vorticity maximum providing just a little additional
lift...but no accumulation is expected. Northwest winds will
continue into Monday...with cooler temperatures and clearing skies
continuing into Monday night. Temperatures do look to make some
recovery on Tuesday...with southwesterly low- to middle-level winds.
Though there are significant differences among models regarding
strength and placement...models do suggest a deepening shortwave
trough or compact upper low descending from the northern plains
toward the Midwest on Tuesday night/Wednesday. Current temperature
forecast would indicate a potential mix of precipitation in the
northern County Warning Area on Tuesday evening before changing to snow...but
again...with only light accumulations /if any/ as solutions keep the
more moderate precipitation amounts to the east of the County Warning Area.
Long term...(wednesday night through sunday)
issued at 249 PM CST sun Nov 23 2014
Colder temperatures are once again prognosticated to spill into the
plains/Midwest in wake of the upper-level system on Wednesday night.
Some model solutions then carry a band of light snow on the west
side of the upper-level low on Wednesday night along the middle-level
thermal gradient...extending from western South Dakota into central/northern
Nebraska. Confidence remains low in this materializing...and if
so...where/when...but for now...have included slight chance probability of precipitation in
the northern County Warning Area. Thanksgiving day is likely to be on the cold side
in the region...but chances for measurable precipitation look low.
Warm air advection is prognosticated to begin on Thursday
night/Friday...though black Friday morning is likely to be on the
cold side...with warming above freezing later on Friday. Warmer
temperatures are likely to continue through Saturday...with the
potential for another cold air intrusion sometime around the weekend
in wake of another surface cold front...followed by high
pressure...and with dry weather likely through the weekend.
Aviation...(00z tafs for kofk...klnk and koma.)
Issued at 532 PM CST sun Nov 23 2014
VFR conditions early...although expecting MVFR clouds to redevelop
at kofk by 04z...and koma/klnk by 07z. Could also see some
flurries at kofk 06-10z. Depending on how they develop...may have
to add to koma later on...but nothing measurable expected.
Conditions back to VFR by 16z. Northwest winds will also prevail
at 18 to 24 knots sustained...with gusts up to 28 to 34 knots at