565 
FXUS63 KOAX 190440
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1140 PM CDT Thu Mar 18 2021

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 326 PM CDT Thu Mar 18 2021

.Today and Tonight:

Recent surface analysis and water vapor imagery noted a mature 
mid-latitude cyclone centered over the southeastern CONUS that is
slowly loosening its influence on the local area. Northeasterly 
winds are currently in place across the region, with wind gust 
speeds ranging from the upper teens to just over 25 kts. Generally
clear skies are also in place with some spotty cumulus, allowing 
for our daytime temps to max out in the lower 50's this afternoon.
Looking at the upper-level pattern, the central CONUS is in a 
transition pattern between building ridging to the west and 
departing troughing to the east. Overnight and into the morning, 
diminished winds are expected to begin swinging southeasterly. 
Some short term models are hinting at some patchy fog along the 
NE/SD border, but model trends throughout the day have backed off 
most of the patchy fog north into South Dakota. Clear skies will 
allow us to fall to temperatures in the mid-to-upper 20's, making 
for a cooler night that we've seen recently.

.Friday through Sunday:

Friday through the weekend will see building ridging transition into 
the area from the west, joining southerly flow at the surface and 
high pressure to the east to kick off a warming trend for the area. 
High temperatures are expected to go from the mid 50's on Friday to 
as warm as the mid-to-upper 60's by Sunday afternoon. While lighter 
southerly winds are expected for Friday, the surface pressure 
gradient is expected to increase Saturday and Sunday, allowing for 
afternoon winds gusts to reach 25 to 35 kts. At the same time our 
local area is warming and gusting this weekend, troughing is making 
landfall to the west and heading towards our area.

.Monday through Wednesday:

Deterministic global models are in good agreement that leeside 
cyclogenesis is expected to occur in northeast NM/Texas and Oklahoma 
Panhandle region Monday afternoon. To the north of this region, a 
stalled out cold front turned stationary front is expected to bisect 
eastern Nebraska and extending southwest and northeast from eastern 
Nebraska. Along the front, light rain is expected to develop in the 
region Monday night as southerly flow to the south of the stationary 
aids in overrunning of the boundary. Throughout the day Tuesday, the 
system on the lee of the Rockies is expected to strengthen quite a 
bit, ramping up moisture transport and begin ejecting NNE towards 
the general area. 

Global models have some uncertainty in terms of how far north the 
strongest moisture transport is expected to reach, but ensemble 
situational awareness from the NAEFS and EPS both show an 
anomalously moist air mass making its way to the region. Both
ensembles suggest PWat values over 0.75" pushing north into the
area. Current deterministic runs of the global models have been 
tracking the surface low so that eastern Nebraska and western Iowa
experience both warm sector and post-frontal deformation band 
precipitation, and are heavy with the precipitation across the 
area. Looking at ensemble means, both GEFS and EPS means average
lower values at just under 2" over the course of the early work 
week with some clustering near the deterministic runs. The vast 
majority of the precipitation is expected to fall as rain, with 
some snow sneaking in on the backside as you get closer to central
Nebraska as the system pivots out of the area Wednesday. Overall 
the signals for another healthy rainfall event are here, we will 
have to continue monitoring model trends to see if the current 
placement of precipitation remains on track. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1139 PM CDT Thu Mar 18 2021

VFR conditions will prevail through the forecast period. Some 
patchy fog is possible in the KOFK vicinity around 12z Friday. 
Light northeast winds will become southeast on Friday morning and 
gradually increase during the afternoon.

&&

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

$$

DISCUSSION...Petersen
AVIATION...Mead