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fxus63 ktop 161040 

Area forecast discussion
National Weather Service Topeka Kansas
540 am CDT Mon Sep 16 2019

..update to aviation forecast discussion...

Short term...(today and tonight)
issued at 325 am CDT Mon Sep 16 2019

Expansive high clouds are spreading eastward into the Central
Plains this morning, downstream of an upper ridge centered over the
ridge. As the ridge shifts eastward later today, aforementioned
high clouds should have an impact on temperatures this afternoon as
they move across the County Warning Area. Forecast soundings are consistent in the
boundary layer mixing to at least 850 mb by late afternoon. With the
setup pretty similar to yesterday, opted to increase highs by a few
degrees into the lower and middle 90s. The main deterring factor for
highs reaching the upper 90s are the high clouds providing some
insulation. Depth and coverage of the cloud cover are also
somewhat uncertain.

For tonight, Lee troughing off the High Plains to our west induces a
decent sfc pressure gradient as far east as north central Kansas.
South winds here should stay up around 10 to 15 mph. In turn,
overnight lows hold in the middle 70s. Most of the County Warning Area however
cools to around 70 degrees with the light winds.

Long term...(tuesday through sunday)
issued at 325 am CDT Mon Sep 16 2019

Several upper troughs are progged to deepen across the western Continental U.S.
Before lifting across the central and northern plains beginning
late Tuesday evening. Consensus guidance focuses much of the
thunderstorm development from eastern Nebraska through north
central Kansas, along the nose of the inverted trough axis.
Moisture advection is not strong enough for higher pops at this
time so will maintain the slight and low end chances through
Wednesday. Uncertainty in the position of the frontal boundary and
embedded weak waves aloft greatly increase from Wednesday
evening. Believe that the GFS may be overdone and noisy with the
qpf amounts since the better upper lift centers over Nebraska.
Regardless, overall pattern from guidance suggests a slight
possibility for thunderstorms through Friday, particularly during
the overnight period with the assistance of the low level jet.

The main upper low is still on track to lift through the northern
plains Saturday and Sunday, pushing a decent cold front and
higher thunderstorm chances into the region. GFS holds a more
progressive boundary while the European model (ecmwf) continues precip chances
through Sunday so will need to monitor trends. In regards to
temps, most of the precip chances reside during the evening hours
and should not have a huge impact on highs, especially from
Wednesday through Friday. Little changes are anticipated with
readings around 90 degrees before the precip and cloud cover
relieves highs back into the 80s Saturday and Sunday.


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 521 am CDT Mon Sep 16 2019

VFR prevails with southerly winds increasing above 10 kts aft 15z
at kmhk and around 18z at kfoe/ktop. Low level wind shear is marginal late
tonight at kmhk with higher speeds displaced over central Kansas.


Top watches/warnings/advisories...

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