194 
FXUS63 KOAX 072111
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
311 PM CST Thu Nov 7 2019

...Updated Forecast Discussion for Tonight through Thursday...

.DISCUSSION...
Issued at 310 PM CST Thu Nov 7 2019

Forecast Summary: 

Not much of a change to the going forecast through next week. 
Northwest mid level flow will dominate the weather, ushering in 
reinforcing surges of cold air. Will see some modest warming ahead 
of these cold surges, but will be short-lived. Also, there will be 
at least a small precipitation chance on Sunday, but the main 
weather story will be the colder temperatures through the period.

This afternoon through Saturday:

Surface high pressure had settled over eastern Nebraska and 
southwest Iowa this afternoon, bringing mainly clear skies and 
relatively light winds. This scenario allowed temperatures to really 
bottom out this morning, with lows in the single digits in northeast 
Nebraska and teens elsewhere. We were already seeing return flow 
setting up across central and northeast Nebraska with southwest 
winds there. 

Southerly winds will increase later tonight and Friday before 
becoming west and northwest on Saturday after surface trough tied to 
shortwave diving into the northern Great Lakes slides through the 
region. 850 temps in the 6 to 10C below range this morning are 
forecast increase to 2 to 7C Friday afternoon, then closer to 12 to 
14C on Saturday. Mainly clear skies along with favorable warm 
advection pattern will nudge temperatures toward 50 on Friday, then 
into the 60s on Saturday when favorable westerly wind component 
enhances warming.

Saturday night through Tuesday:

Strong cold front is still forecast to plunge through the Plains 
Saturday night and Sunday, ushering in an airmass that is even 
colder than the one currently overhead. 850 temps drop 25 to 30C 
from Saturday afternoon through Monday afternoon, bottoming out in 
the 15 to 20C below range then. Surface temperatures may gain a few 
degrees into the upper 30s to middle 40s on Sunday before cold 
advection kicks in with earnest later in the day. 

ECMWF is the most aggressive of the synoptic scale models in 
developing precipitation with this surge of cold air, indicating 
accumulating snows are possible across all of our area, with several 
inches indicated in northeast Nebraska from Sunday afternoon through 
Sunday night. The GFS is less aggressive with precipitation amounts 
and was favored as the atmosphere remains relatively dry. However a 
deep dendritic temperature regime will favor efficient snow-making 
atmosphere even in low moisture. So will at least maintain small 
snow chances all areas, and paint some minor accumulations across 
our northern CWA.

Surface high pressure settles into the region on Monday before 
retreating east on Tuesday afternoon. Given magnitude of cold 
atmosphere, temperatures will struggle to climb out of the middle 
20s on Monday despite sunny skies. Monday night lows will be the 
coldest of the season so far as all areas should see single digits. 
We could slip below zero in our north if accumulating snow occurs. 
Return flow sets up Tuesday afternoon, but with the cold start to 
the day, we'll likely see another day in the 20s.

Wednesday and Thursday:

Some slight moderation in temperatures is forecast Wednesday as 850 
temps again swing back to the positive side of 0C, but another 
reinforcing shot of colder air will quickly follow Wednesday night 
and Thursday. This system is not nearly as cold and Monday's, but 
will keep temperatures well below normal through Thursday.



&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1114 AM CST Thu Nov 7 2019

VFR conditions are expected across the TAF sites through the TAF 
cycle as an area of surface high pressure moves overhead. Some
mid-clouds in northeast Nebraska will co continue to drift east 
and diminish this afternoon leaving clear skies across the area 
into Friday. As surface high pressure slides east, increasing 
southerly flow will push winds into the 10-20kt range with gusts 
up to 25kts by 18z Friday. 


&&

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

$$

DISCUSSION...Dergan
AVIATION...Kern