National Weather Service Raw Text Product

059 
FXUS63 KOAX 271119
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
519 AM CST Sat Feb 27 2021

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 300 AM CST Sat Feb 27 2021

The main forecast issues are the chance for rain showers and snow
the next 24 hours. 

Two areas of height falls were noted on the 00Z upper air plot at
500 mb last evening. One was centered over MN, moving away from
our area and another was back over OR/UT/NV. There was a 145 knot
jetstreak at 300 mb moving southward from the Pacific Northwest on
the backside of that shortwave trough. This will help bring some 
precipitation to at least parts of our area later today and into
tonight. 

Water vapor loop showed clouds thickening to our west as the
system moves closer. There is still a fairly large spread of model
solutions as to exactly what will happen, but tended to use a
blend of the GFS/ECMWF and some of the short range CAMs. Increased
POPs across much of the area for today, but especially for 
northeast NE. Forecast soundings show that lapse rates will
steepen later today and this evening, especially in southeast NE,
east central NE and southwest IA where RAP model shows some
positive CAPE with parcels lifted from around 825 mb. Slantwise
instability is noted farther north, mainly from MN back into 
parts of eastern SD. Heaviest snow amounts should be up in that 
area where parameters are more favorable and lift is stronger in 
the dendritic growth zone aloft. As for snow locally in our area, 
did increase snow amounts a bit across our northern counties, 
especially Knox and Cedar counties where 1 to 2 inches of snow 
could accumulate. 

Low pressure initially over eastern CO will track toward north
central KS by late afternoon and strengthen. This should bring
gusty south winds to parts of southeast NE and southwest IA, 
where gusts could reach around 35 mph today. It appears the 
surface low will track to near Omaha mid evening, and then to just
north of the MN/IA/WI border area by 12Z Sunday. Brisk northwest 
winds are expected for our area on the backside of the low later 
tonight and Sunday. Highs Sunday should reach the upper 30s to mid
40s with lows Sunday night dropping to the lower and mid 20s. 

Monday through Friday...
This period looks mainly dry. Some model guidance brings a push of
colder air in from the north for Monday and this seems reasonable. 
A weak system does track to our south Tuesday, but not get close 
enough to give us any rain. We we will have to watch for some 
potential light precipitation Thursday into Friday. The 00Z GFS is
still wetter than the ECMWF in that period, but much shows much 
lighter QPF compared to 24 hours ago. 

Here is what we expect for high temperatures next week. 
Monday - mostly in the mid 30s to mid 40s. Tuesday - in the 50s. 
Wednesday and Thursday - mid 50s to lower 60s. Friday - in the 
50s. Saturday - in the 50s to lower 60s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 451 AM CST Sat Feb 27 2021

Deteriorating conditions are expected toward late afternoon in
respond to a passing upper level disturbance. At that time an
areal increase of RA is expected across eastern NE with the
heaviest precip occurring over northeast NE. Given relatively 
high confidence have prevailing RA at all terminals through mid 
evening at all terminals. It appears that KOFK will be right on 
the line separating RA/SN. At this point confidence is low any SN 
will be seen at KOFK. Thus will opt for RA as dominate precip 
type. 

&&

.HYDROLOGY...
Issued at 300 AM CST Sat Feb 27 2021

A flood watch remains in effect until Noon Monday for areas near
the Platte, Elkhorn, and Loup Rivers. Warm weather the past week 
has caused enough snow melt to flush ice out of the Loup Basin. 
Ice jams will be possible the next few days, with the highest
chances of that in the Platte River. See specific warnings for 
details.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flood Watch through Monday morning for NEZ016-031>033-042>045-
     050>053-067.

IA...None.
&&

$$

DISCUSSION...Miller
AVIATION...DEE