Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 210416
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1116 PM CDT Mon Mar 20 2017

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Tuesday)
Issued at 340 PM CDT Mon Mar 20 2017

A weak SW to NE oriented boundary cleared the CWA this morning and
was positioned along a line from St. Louis to Ponca City by the mid
afternoon. This surface boundary will transition into a stationary
boundary over Oklahoma tonight and linger south of Kansas through
the day on Tuesday with zonal flow in place aloft. Canadian high
pressure builds south tonight and will usher in cooler air over the
next 24 hours as H850 temps fall to 2-3C by Tuesday afternoon.
Easterly flow under an H750 inversion will prevail through the day
on Tuesday with stratus building across the southern CWA. Highs on
Tuesday will fall back to "average" for this time of year with
readings in the upper 50s to around 60. There remains a slight
chance of precip across the southern CWA tomorrow morning closer to
the elevated front as a weak H500 wave moves through the flow.
NAM/RAP profiles do hint at some MUCAPE with low CINH, but with the
forcing being on the weak side, the overall threat of rain is low.
Recent ARW/NMM/HRRR/NAM/NCAR Ensemble runs are also trending in this
direction in either not developing precip or keeping any convection
south of the area.

.LONG TERM...(Tuesday night through Monday)
Issued at 340 PM CDT Mon Mar 20 2017

The long term period is quite active in terms of multiple storm
systems crossing the region. This will also feature multiple
fronts and temperature swings in association with these storm
systems.

The first system is a vort max moving out of the northwest from
Nebraska toward northern Missouri. Expect one or more bands of
frontogenetical lift to result in banded precipitation while warm
advection from the south may result scattered showers from eastern
Kansas into Missouri. The northern precipitation may be in an
airmass cold enough to support a rain snow mix, but will be
primarily dependent on how intense the precip falls. If precip is
heavier within a band, there is a better chance of snowflakes
reaching the ground. In the end, this snow potential is rather low
and warm ground temperatures should preclude any accumulation.

Upper ridging builds into the region for Thursday with increasing
warm and moisture advection into the region. The low levels will
remain cool but expect eventual saturation to result in potential
for light drizzle or rain, and there are indications that elevated
parcels may be supportive of an area elevated thunderstorms. The
best chance for thunderstorm activity seems to be late Wednesday
night into early Thursday from east central Kansas into northern
Missouri. If storms develop, there may be a small chance for some
hail but will depend on how impressive elevated instability/shear
profiles become.

A powerful storm system ejects into the Plains late Thursday into
Friday but becomes vertically stacked and occluded over Kansas.
There appears to be a very good chance for precipitation, with
thunderstorms likely as well. Wind shear will be strong but wind
profiles are very meridional and expect convective interaction to
minimize overall severe threat. This may result in some moderate
to heavy rain at times though which will be largely welcome across
the area. If there is a chance of strong to severe storms, it may
focus in the form of low-topped supercells on Friday as the
surface and upper lows cross central and eastern Kansas. The main
question is how far east the instability will extend, and current
indications are that the bulk of instability will hold west of the
KS/MO border. As the storm system passes through, additional
precip will wrap around the north and northwest quadrants of the
upper low and expect a cold rain at this time with upper
temperatures probably too warm to support snow.

Another impressive but quick-hitting system will cross the region
on Monday but it appears that moisture may be limited. Will want
to monitor moisture return from the gulf, and if dewpoints can
make it into the 60s, may have to monitor for severe potential.
Another powerful storm system is likely to impact the region by
the middle of next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1108 PM CDT Mon Mar 20 2017

Will keep VFR conditions in the forecast with VFR stratus expected
to develop after 12z with weak lift north of elevated boundary.
Expect northeast winds with gusts forecast to develop after 12z as
well.

&&

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

$$

SHORT TERM...Skow
LONG TERM...Barjenbruch
AVIATION...Omitt


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