Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 212320

National Weather Service Topeka KS
620 PM CDT SAT MAY 21 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Sunday)
Issued at 300 PM CDT SAT MAY 21 2016

Upper ridge axis remains to the west today with lower cloud
continuing to push east on a shallow area of westerly winds.
Steady mid-level isentropic lift attempting to generate light
precip in still limited deep moisture and instability. HRRR
continues to be overdone on intensity and coverage of precip, but
it along with ARW, NMM, and larger-scale models are consistent
with light precip continuing to bubble in east central Kansas
through the evening hours and will keep small chances going here.
Models are also consistent with isentropic upglide diminishing
overnight as the ridge axis moves overhead. Will go ahead and keep
a small thunder chance in western areas late tonight into Sunday
morning with minor potential for convection over western Kansas
making its way in but instability again remains weak. Stronger
lower-level southerly winds tonight into Sunday bring warmer air
in, so though cloud may again be persistent, expect highs several
degrees warmer than today.

.LONG TERM...(Sunday Night through Saturday)
Issued at 300 PM CDT SAT MAY 21 2016

For Sunday night through Thursday, models show a conditionally
unstable airmass remaining over the central plains with southwest
flow aloft. However the flow aloft is not very strong and any
large scale forcing appears to be rather subtle. Models continue
to show 0-6km shear to be just adequate for organized severe
weather, generally in the 30 to 40 KT range. So with increasing
low level moisture moving north and nothing to really change the
airmass, it is difficult to pick out a period where there is not a
chance for precip. While the overall synoptic patterns are in
reasonable agreement, the models have shown a tendency to be
rather inconsistent in the display of QPF which maybe should be
expected given the convective nature of the storms. By Thursday
night and Friday, there is some agreement between the ECMWF and
GFS that a better defined wave will lift out of the southern
Rockies and across the plains. However the latest 12Z runs have
some timing differences with the upper low passing over the area.

In general this is not a very satisfying forecast and confidence
in any given period is not very high. With some potential for
precip through the extended, have relied more on the model
consensus which generally fits in with the previous forecast.

Models have slowed down the timing of storms over the high plains
moving into the forecast area late Sunday night. It appears as
though the low level jet remains over western KS through the
evening, so with no obvious synoptic forcing have lowered POPs
Sunday evening and lowered POPs for eastern KS early Monday
morning. The boundary is expected to be closer to the forecast
area during the day Monday and hangs out through the week. Lift
along the boundary and little to no inhibition to convection
continues to support likely POPs for Monday. After that it is
unclear how convective overturning and potential outflow
boundaries will impact precip chances. Therefore only have chance
POPs through the remainder of the forecast.

Models continue to show a warm up through mid week as 850 MB temps
warm to around +20C. So highs in the lower to mid 80s seem
plausible. By Friday and Saturday, the forecast cools temps
slightly as the upper wave moves over the plains with perhaps a
little better chance for clouds and precip. Lows are forecast to
remain mild with little or no cold air advection expecting
readings in the lower and mid 60s.


.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 618 PM CDT SAT MAY 21 2016

VFR conditions are expected throughout the period. VCTS was
included at TOP/FOE for a line of scattered showers with isolated
thunder expected to move east of the terminals by 03Z. Winds will
generally stay out of the ESE or SE with gusts up to 20kts
possible at MHK in the afternoon.


.TOP Watches/Warnings/Advisories...


LONG TERM...Wolters
AVIATION...Heller is the U.S. government's official web portal to all federal, state and local government web resources and services.