645 
FXUS63 KOAX 272145
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
345 PM CST Mon Dec 27 2021

...Updated Forecast Discussion...

.DISCUSSION...
Issued at 341 PM CST Mon Dec 27 2021

Forecast Summary:
The warm weather regime is coming to an end and temperatures in 
the area are forecast to primarily be below average for the next 
week. There is also a couple of small chances for precipitation 
tomorrow and Wednesday. Chances are increasing for an impactful 
winter weather system over the holiday weekend.

Today through Thursday:
Temperatures have remained on the cool side today as cold air
advection was stronger than anticipated. Temperature are 10 to 15
degrees cooler from 24 hours ago. A further cool off is forecast
for tomorrow as a cold front will begin to move through the area
in the mid-late morning. There is a wide range for the high
temperature forecast tomorrow as the front won't allow for
temperatures in northeast Nebraska to peak in the mid afternoon.
While in southeast Nebraska and Iowa, strong southerly flow ahead
of the surface low should advect a brief, warm air nub. Thus, 
temperatures in Hartington, NE are expected to peak at 29 degrees 
while Falls City should be near 55 degrees. 

Winds behind the front will be strong at 20 to 25 mph from the 
northwest with gusts up to 30 mph. The wind combined with the 
cooler temperatures will produce a wind chill that many might not 
be quite ready for due to one of the warmest Decembers on record.
Low temperatures Wednesday morning are forecast to dip into the 
single digits in far northeast Nebraska. The wind chill for many 
locations will be near 0 or below. High temperatures Wednesday 
aren't expected to be above freezing for any location in the 
forecast area. 

There is about a 30% chance for snow Wednesday morning and 
afternoon, though there is still some uncertainty. A weak 
shortwave and a weak isentropic lift may be enough forcing to lead
to some light precipitation. Accumulations are not expected to be
any more than an inch. Precipitation should be all snow, so it 
would seem this possible event should have minimum impact if
precipitation does materialize. 

Temperatures should rebound somewhat Thursday with 30 degrees forecast
along the South Dakota border and low 40s forecast along the 
Kansas border.

Friday through Monday:
An impactful winter weather system is expected to move through the
forecast area this weekend. A deep upper level trough will move
across the Rocky Mountains producing a classic Colorado low.
Confidence is high in much colder temperatures. Low temperatures
Saturday and Sunday are forecast to drop below 0 for many
locations. Wind chill values for locations in northeast Nebraska
could reach -20. There is more uncertainty in snowfall (locations
and amounts), but medium range guidance is starting to come into
better agreement. The surface low will help advect gulf moisture
northward, so there is potential for plowable snow and then some.
It's still too early to talk snowfall totals. If widespread snow
cover occurs, it would be reasonable to expect colder 
temperatures even farther to the south.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1128 AM CST Mon Dec 27 2021

VFR criteria to prevail for the TAF period. Winds will shift this
afternoon by 22Z, changing from northwest to southeast. An 850 hPa
jet near 50 kts is expected to develop again, which should lead to
criteria level LLWS between 07Z and 14Z.


&&

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

$$

DISCUSSION...Fajman
AVIATION...Fajman