692 
FXUS63 KOAX 021700
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1100 AM CST Sun Feb 2 2020

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 333 AM CST Sun Feb 2 2020

At 333 AM, upper level ridging was in place over the Plains, with
dry conditions from Texas to the Dakotas. Strong mid level winds 
blowing across the spine of the Rockies were helping to generate 
widespread high clouds over Nebraska and Iowa. Surface winds were
still westerly over most of the region as well, and this was 
keeping temperatures up, with most locations still in the 40s as
of 3 AM. Where wind had calmed down, temperature were falling
rapidly into the 30s.

The challenge in today's forecast remains the temperature dichotomy. 
Westerly winds this morning will transition to northeast winds by 
sundown in response to a developing lee trough over the High 
Plains of Colorado and a cold front sagging south. The timing of 
this transition should dictate afternoon high temperatures today.
Although the warmth of the surface to 850 mb layer will also play
a role. Guidance favors the arrival of northeast winds in western
Iowa and northeast Nebraska by 2 PM, with winds not turning along
the NE/KS border until 5 PM or so. This is a couple hours slower 
than what we were looking at 24 hours ago, and it suggests 
slightly warmer temperatures this afternoon. In general it looks 
like lower 60s are possible south of Lincoln, with temperatures 
trending toward the upper 40s as you approach the NE/SD border. 
Besides the unseasonable warmth, today will also be the last 
mostly sunny day for a while, so you might want to step out and 
fell the rays for a bit so you can remember what it feels like. 

A strong upper level trough will descend from the Pacific 
Northwest into Colorado Monday, bringing a significant winter 
storm to the Rockies and High Plains. Certainly looks like the ski
resorts will be happy. Meanwhile eastern Nebraska and Iowa will 
enjoy the effects of a surface low as it moves along the NE/KS 
border. This will bring gusty north winds to the region Monday, 
and potentially produce some freezing drizzle or light snow. Only
a couple hundredths of an inch of precipitation are possible
Monday. However with precipitation being in the "freezing" 
category, minor impacts may occur, and later shifts may need to 
ponder a Winter Weather Advisory (Advisory potential ~35%).

There are some noteworthy changes to the forecast Tuesday and 
Wednesday as the core of the upper level trough shifts east. 
Namely, models are trending toward a weaker and more elongated 
upper level trough, with the "strength of the trough" tracking 
further south. This has consequences for our snow potential, as 
it leaves the better lift to our west and moisture to our south 
and east. Depending on which guidance you look at, dry air in the 
mid levels could also impact snow potential. As a consequence the
snow forecast has been reduced from 1 to 4 inches at this time 
yesterday to a Trace to 2 inches this morning. If you want higher 
snow totals, you will likely have to head to western Nebraska. 
Where snow does fall, it should be light and fluffy (given snow 
ratios of 15:1 to 20:1), and may blow or drift in gusty north 
winds (gusts 20 to 35 mph). The opportunity for adverse weather 
impacts Tuesday and Wednesday appears to be decreasing and the 
potential for any sort of winter products seems low (Advisory 
potential ~15%)

Troughing over the Great Lakes and subsequent northwest flow 
aloft in the Northern and Central Plains remains the going 
forecast Thursday through Saturday. If this holds, there could be 
a couple opportunities for light precipitation during this period.
That said the latter half of the week still appears mostly dry. 
Temperatures may also recover some during this period as 500 mb 
heights increase. The going forecast suggest upper 30s or low 40s 
by Saturday. 

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1059 AM CST Sun Feb 2 2020

A weak cold front will move through the area this afternoon with
light west or northwest winds switching to north-northeast at less
than 10 kt. Late tonight into Monday morning, an approaching
weather disturbance will result in ceilings lowering to MVFR with
the potential for some freezing drizzle at KOMA and KLNK. Winds
will concurrently strengthen from the northeast at 15G25KT.

&&

.HYDROLOGY...
Issued at 333 AM CST Sun Feb 2 2020

Brief ice jams will remain a possibility (mainly along the Platte 
River) through the day today. Should any jams occur, minor flooding 
will be possible. If you live along the river it would be prudent to 
continue to watch river conditions today. A positive of the 
elevated risk for ice jams today is that we are clearing ice out 
of the system. A slight tap of the reset button as we enter the
last traditionally cold month of the season.

&&

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

$$

DISCUSSION...Albright
AVIATION...Mead
HYDROLOGY...Albright