Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 241127
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
527 AM CST Tue Jan 24 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 319 AM CST Tue Jan 24 2017

A powerful storm system is forecast to cross the region today,
interestingly with little to no impactful sensible weather in the
local forecast area but significant winter weather to the north.

Early Tuesday morning, surface low pressure was centered over far
southeast Colorado with falling pressure across all of Kansas. The
heart of the upper low was located over central Wyoming but a 120+
kt jet with embedded 140 kt jet streak was building its way across
the central Plains and a strengthening short wave trough was moving
out of the Four Corners region. Elevated echoes were developing
across north central KS in association with a weak embedded lead
short wave and the left exit region of the incoming jet streak.
Expect an area of rain/sleet/snow showers to develop over the next
couple of hours and move quickly northeast. Some of this activity,
likely in the form of rain/sleet showers may impact areas north of a
Concordia to Marysville line this morning before moving off.

As the day progresses, the surface low will deepen and move into
central...and eventually northeast Kansas. Winds will become gusty,
into the 30-40 mph range at times locally, and will advect plenty of
warm air into the forecast area with highs likely to climb into the
50s for much of the area, and even 60s near/south of I-70. The
temperature gradient will be tight though as the surface low will
track almost directly through the middle of the forecast area, and
south central Nebraska is likely to hold in the 30s for highs.
Additional rounds of showery precipitation are expected to develop
amidst weaker embedded disturbances through the day, keeping a need
for at least slight chances of rain showers over northern Kansas for
much of the day, but the majority of this lift/moisture combination
will remain northwest of the local forecast area through the day.

Even through the night, the vast majority of precip will remain
north of the local forecast area. The ECMWF is the only model to
bring any precip as far south as I-70, and only the Canadian and
ECMWF bring precip south of a Concordia to Atchison line. Given
current conditions and expected track/forecast soundings, have kept
pops generally close to or north of that Concordia to Atchison line
through the storm passage. Any precip will most likely fall as rain
today but during the evening temperatures will plummet as the low
passes and there is a small chance for light snow or even a brief
period of light freezing rain/drizzle. Little to no accumulation of
precip/snow/ice is expected given only light QPF and warm ground
temperatures.

.LONG TERM...(Wednesday through Monday)
Issued at 319 AM CST Tue Jan 24 2017

The midlevel closed trough lifts towards the Midwest region on
Wednesday. Latest models are continuing to trend similarly to
previous runs with wraparound light snow impacting areas north of
Interstate 70, primarily near the Kansas and Nebraska border in the
morning and afternoon. A light dusting is possible at best with a
few hundredths of qpf expected.

The cold, more seasonable airmass funnels southward through the
remainder of the week as an open, midlevel trough retrogrades
towards the southwest in response to a building ridge over much of
the western conus. Highs are generally in the upper 30s while
overnight lows read near 20 degrees. Clouds will be periodic with
the strongest areas of lift and moisture just east of the CWA. This
may change however by Sunday as an upper trough swings directly
south through the plains region. The GFS resides the axis directly
over the area while the ECMWF is focused into western Missouri.
Decided to keep the mention of light snow in the morning followed by
rain in the afternoon. At this time, the system is pretty
progressive so would not expect any accumulation or hazards.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 527 AM CST Tue Jan 24 2017

Ongoing LLWS will subside between 13-15Z for all sites, and VFR
conditions are expected throughout the period.  Winds will begin
gusting up to 25kts by early morning and continue through the
afternoon, and once again in the evening.  Southeast winds this
morning will veer throughout the day, persisting from the west by
00Z.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Prieto
AVIATION...Heller


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