907 
FXUS63 KTOP 021810
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1210 PM CST Sat Mar 2 2019

...Update to aviation forecast discussion...

.SHORT TERM...(Today through Sunday)
Issued at 357 AM CST Sat Mar 2 2019

Surface ridge axis was over the Missouri river early this morning
with plenty of mainly mid and high cloud over the central Plains
downstream of a shortwave trough off the California coast.
Regional radar returns are increasing as a weak wave approaches
resulting in modest mid-level warm air advection. This setup
continues into midday and moisture depths may increase enough in
far northern locations of the local area for some light snow to
fall early today with low-level east to northeast winds keeping
the lower layers dry. 

Much more widespread and impactful snowfall is expected tonight
into early Sunday as the California wave quickly passes through.
There continues to be some variability in the details of amounts
and timing, though confidence in a few to several inches of snow
falling in increasing low-level winds is high. The most likely
area of heavier amounts remains in the southwestern half of the
local area where stronger frontogenesis and a less statically-
stable layer exists. Ageostrophic response is fairly strong and
SREF means continue to show some higher rates possible and support
the notion of much of the snow accumulating over the 6-10 hour
window. Increasing and deep cold-air advection in the later
portions of Saturday night into Sunday via a 1050 mb high building
southeast into the northern Rockies and cyclogenesis to the
southeast will support high snow-to-liquid ratios with time and
surface temps in 10-23 degree range in combination with 925mb
winds in the 25-30 knot range will support blowing and drifting
snow in the middle to perhaps well past the end of the
precipitation into Sunday afternoon. Expected snowfall with the
wind has pushed the Winter Storm Warning on southeast across much
of east central Kansas, and nearly-steady temps to combine with
the wind to bring Advisory-needing wind chills to much of the
north and northwest. Record lowest-maximum temps for Sunday will
be approached depending on specific values near midnight tonight. 

.LONG TERM...(Sunday night through Friday)
Issued at 357 AM CST Sat Mar 2 2019

By Sunday night, expansive surface high pressure will continue to 
spread across the central U.S., with northwesterly winds continuing 
to usher much colder air into the region.  The combination of these 
northwesterly winds and mostly clear skies will result in decent 
radiational cooling, causing overnight low temperatures to plummet 
into the negative single digits across the entire outlook area. With 
sustained northwesterly winds of 5-10 mph, wind chill values look to 
plunge into the -12 to -24 degree range. As a result, anticipate the 
need for Wind Chill headlines eventually for this time period.  

A brief stretch of drier conditions is expected through the first 
half of next week as surface high pressure remains anchored over the 
central U.S.  Persistent northerly winds will keep temperatures on 
the colder side with Monday highs in the teens and Tuesday highs 
into the 20s.  As a mid-level ridge begins to build into the central 
U.S. by mid-week, it will help to shift the high pressure further 
east, thus causing winds to become more southerly.  This shift to 
southerly winds by Wednesday will help to boost high temperatures 
into the 30s.  

The weather pattern looks to become more unsettled by late week into 
the weekend as models show two embedded shortwave troughs skimming 
eastward across the central U.S.  The first embedded shortwave may 
bring precipitation chances back into the area by Thursday into 
Friday with a deeper mid-level trough expected to bring additional 
precipitation chances over the weekend.  There is still notable 
variability with the exact tracking, timing, and strength of these 
disturbances, however periods of a rain/snow mix may be possible as 
highs rise into the 30s/low 40s and overnight lows drop into the 
teens/20s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1142 AM CST Sat Mar 2 2019

VFR conditions continue into the evening before conditions
deteriorate into the 06Z time frame. Light snow develops from west
to east. High confidence int the 06-12Z period seeing the most
significant impacts across the area. While some of the snow
expected will likely be heavy, still a little uncertain on where
exact bands will be, so have opted to keep visibility to IFR
levels. Could certainly see LIFR or VLIFR for periods. Right now
going with -SN until smaller scale details come together and bands
can be timed into the sites. Conditions improve fairly rapidly
by the end of the period as snow exits the area to the east.  

&&

.CLIMATE...
Issued at 357 AM CST Sat Mar 2 2019

Record Lowest Maximum Temperatures
----------------------------------
            March 3     March 4
Topeka     16 (1978)    9 (1960)
Concordia  12 (1960)    9 (1960)

Record Minimum Temperatures
--------------------------------
            March 4     March 5
Topeka     -7 (1978)   -1 (1960)
Concordia  -7 (1978)    2 (1960)

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 8 PM this evening to noon CST 
Sunday for KSZ008>012-022>024-026-038>040.

Wind Chill Advisory from 6 AM to noon CST Sunday for KSZ008>011-
020.

Winter Storm Warning from 8 PM this evening to noon CST Sunday 
for KSZ020-021-034>037-054>056-058-059.

&&

$$

SHORT TERM...65
LONG TERM...Hennecke
AVIATION...Drake
CLIMATE...65