450 
FXUS63 KOAX 232030
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
330 PM CDT Mon Mar 23 2020

.DISCUSSION...
Issued at 330 PM CDT Mon Mar 23 2020

The main forecast issues in the short term are the chances for
showers and a few thunderstorms tonight into Tuesday morning, 
along with potential for fog which could become locally dense. 

The following large scale features were noted in upper air maps at
12Z this morning. A jet streak of around 140 knots at 300 mb 
extended from southern CA into northern AZ. This was associated 
with a shortwave trough at 500 mb from NV into southern CA, which 
had an area of 12 hour height falls of up to around 50 meters. 
There was actually a fairly large area of mid level height falls 
over the western US and the strongest of those were over the 
Pacific NW. 850 mb moisture was somewhat limited in our area, with
the highest values from south TX into the Gulf Coast states. 
Water vapor satellite imagery early this afternoon showed that the
shortwave trough mentioned earlier had pushed into UT and 
northern AZ. At the surface, high pressure was off to our east and
we were in south or southeast low level flow.

Mid level convective clouds were starting to increase over parts
of western NE as of mid afternoon, while here in eastern NE and
southwest IA low clouds remained. There was some thinning in parts
of southeast NE. Clouds could continue to break up for a while
this evening, but will likely fill back in. Models suggest some
fog will also redevelop, with visibilities dropping to maybe 2
miles or less mainly in the western parts of eastern NE. As the
shortwave to our west moves east, it should bring a chance for
showers and perhaps a few thunderstorms. Will keep some mention 
of possible thunder overnight, mainly for parts of southeast NE. 
The heaviest rain should stay south in KS, but will include some 
rain amounts possibly approaching a tenth of an inch south of I-80
in southeast NE. Look for lows tonight in the upper 30s and lower
40s. Rain chances will linger Tuesday morning, but currently have
a dry forecast for the afternoon. Temperatures should be warmest 
in our western counties, where more sunshine is possible. Look for
highs in the 50s to lower 60s. 

Tuesday night should be dry, but another system moves in by early
Wednesday. This will help drive a fairly strong cold front through
the region. Have rain chances at mostly 20 to 60 percent, and kept
a small chance of thunder late in the afternoon. We should see a
fairly large range of high temperatures Wednesday, from near 50 
at the SD border to around 70 at the KS border. North winds behind
the front may gust to over 30 mph in the afternoon and early 
evening. 

Wednesday night into Saturday evening. 
At the start of this period, there should be a mid level trough
extending from northern Saskatchewan to northern CA. Our area will
be mostly in southwest flow. By early Friday, the flow becomes
somewhat split. A fairly strong disturbance will push through
Friday into Saturday. This will be an active period, with chances
for mostly light rain, but some snow or at least a mix could 
occur in northeast NE Wednesday night into Thursday morning.  
Light accumulations, less than an inch, appear possible in 
northeast NE. There could also be a mix again Thursday night for 
the same area.

Saturday night into Monday.
This period looks mainly dry with highs in the upper 50s and lower
60s for Sunday, then in the 60s Monday. 

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1220 PM CDT Mon Mar 23 2020

Ceilings should slowly lift this afternoon with MVFR conditions
then prevailing into the evening. Conditions will deteriorate
tonight, with ceilings lowering. Expect some fog, especially at
KOFK and KLNK along with potential for some light rain. Thunder
possible, west of KOFK and south of KLNK later tonight but did not
mention in TAFs at this time. 

&&

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

$$

DISCUSSION...Miller
AVIATION...Miller