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fxus63 ktop 222347 

Area forecast discussion
National Weather Service Topeka Kansas
647 PM CDT Thu Aug 22 2019

issued at 253 PM CDT Thu Aug 22 2019

A weak area of cyclonic flow was noted over western and central Kansas
per the 19z water vapor and profiler data. Further west a longer
wavelength upper trough was moving across the intermountain west
while a closed upper low spun over the Gulf of Alaska. At the
surface, high pressure centered over the upper Midwest was ridging
into northeast Kansas. Although there hadn't been much relief from the
dewpoint temps that were still in the lower 70s on the southern and
western periphery of this surface ridge. Diurnal heating of this
moisture along with the upper disturbance just west of the forecast
area looks to be responsible for the showers and storms persisting
across central and southeast Kansas.


..update to aviation forecast discussion...

Short term...(this evening through friday)
issued at 253 PM CDT Thu Aug 22 2019

For this evening, the models now prog the upper disturbance to
shear out and drift southeast. As a result, the 12z solutions have
trended dryer from the previous forecast. Additionally models
show the low level jet to remain backed out of the southeast
nosing into the High Plains. So with only subtle synoptic dynamics
and no obvious lift overnight, think the scattered showers and
storms will fall apart once the boundary layer begins to cool. Low
level flow is expected to remain out of the east through the
night with models maintain some high relative humidity values in the boundary
layer. Forecast soundings keep some decent low level winds in the
15 to 20 knots range just above the surface. So with no significant
dry air advection, think some low clouds could redevelop
overnight. Because of this have generally kept lows in the mid and
upper 60s for most areas. Far northeast Kansas could see a little
more dryer air move in so lows around Brown co are expected to
fall into the lower 60s.

Friday looks to be dry for the most part with low clouds eventually
scattering out as the boundary layer begins to deepen and mixing
increases. There isn't much in the way of forcing progged to move
across the area while surface ridging remains over the forecast
area. But I cannot rule out a diurnally driven shower as the
boundary layer heat up. So will keep a slight chance pops in the
afternoon across east central Kansas where the low level moisture is
expected to be deeper. Highs are forecast to reach the lower 80s.
Think there should be decent insolation with no real cold air
advection to speak of.

Long term...(friday night through thursday)
issued at 253 PM CDT Thu Aug 22 2019

For Friday night through Sunday night, models continue to show
subtle forcing potentially moving across the area. Meanwhile
moisture is progged to remain over the area with precipital water
values between 1.5 and 2 inches. So chance pops remain in the
forecast. The better chances look to be Saturday morning and then
again Saturday night and into Sunday morning. Models show a 500mb
wave moving through western Kansas late Friday night with indications
of an mesoscale convective system moving towards the forecast area. This looks to become
less organized as it moves towards the forecast area with the
models showing the wave shearing out. Then a second wave is
progged to be over the area Saturday night and Sunday morning.
Temps through the weekend look to be pretty similar to today as
models show little change to the airmass. Additionally clouds and
precip chances may inhibit a strong warm up. So highs are expected
to remain in the upper 70s to the lower 80s. Lows should continue
to be in the 60s.

A frontal system is expected to bring the next chance for precip
Monday and Monday night. Then uncertainty in the forecast begins
increasing for the later part of the forecast. The GFS shows a
second and stronger front moving through by Wednesday while the
European model (ecmwf) maintains southerly low level flow with a less amplified
synoptic pattern and the bulk of the westerlies remaining across the
northern plains. Because of this, the forecast relies heavily on the
model blend which could have a higher potential for a busted
forecast since the blend is of warm and dry weather with cool and
wet weather. Pops are generally around 30 percent. And the temp
forecast is for highs around 80 with lows around 60. Hopefully
models will converge on a common idea in the coming runs.


Aviation...(for the 00z tafs through 00z Friday evening)
issued at 644 PM CDT Thu Aug 22 2019

The thunderstorm across southwest Geary County should dissipate
before reaching the mhk vicinity early this evening. Kmhk may see
some MVFR stratus develop after 6z Friday. Ktop and kfoe will see
stratus but it should remain above 3000 feet. The Friday morning
stratus will scatter out by Friday afternoon.


Top watches/warnings/advisories...


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