Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 162330

National Weather Service Topeka KS
630 PM CDT Sun Oct 16 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Monday)
Issued at 242 PM CDT Sun Oct 16 2016

A broad upper level trough was located across the western US. A
shorter wave length upper trough was moving onshore across northern
CA and will lift east-northeast across the central Rockies early
Monday morning, then into the central and northern high plains by
00Z Tue. The strong mid level flow across the central rockies will
deepen a lee surface low across southwest KS Monday afternoon. 850mb
winds will remain from the southwest Tonight into Monday. WAA at
850mb will cause 850mb temps to rise between 22 to 25 DEG C on
Monday. Point forecast soundings across the CWA show that the
boundary layer will mix between 800-850mb, therefore high
temperatures will reach into the upper 80s to lower 90s across the
CWA. 850mb winds will be from the southwest at 45 to 50 KTS, thus
the steep dry adiabatic lapse rates between the surface and 850mb
will provide for good momentum transfer form parcels at 850 mb
towards the surface. Sustained surface winds will be south-southwest
at 20 to 30 MPH with gusts of 30 to 40 MPH. The stronger corridor of
winds will be across northeast and east central KS from the late
morning hours through the afternoon hours.

The WRF model solutions show areas of fog developing across north
central KS late Tonight and through the mid morning hours of Monday.
Given the stronger LLJ developing later Tonight, I do not expect
that any fog that may develop will be dense. Farther north across NE
and IA there is a better chance for widespread dense fog to develop.
Overnight lows will only drop into the 60s.
!--not sent--!

.LONG TERM...(Monday night through Sunday)
Issued at 242 PM CDT Sun Oct 16 2016

After cold frontal passage Monday night, flow aloft become mostly
zonal which leads to a mostly dry forecast for the rest of the
week. However, precip chances non-negligible for Tuesday night
into Wednesday as broad and low amplitude upper trough crosses the
Central U.S. Isentropic lift could be enough to set off some
showers, with perhaps a little thunder over east central KS during
that time frame. ECMWF has been the most aggressive with
lift/precip in eastern KS on the last runs, while GFS and GEM/CMC
have trended more southward with the precip. Cooler air aloft
moving through northeast KS Wednesday night and Thursday could
lead to isolated light showers/sprinkles, but have gone less than
20 percent at this time. Gradual warmup expected late week/into
the weekend as low-level warm advection leads to rising heights
aloft and some warming at the surface. Daytime highs in the 60s on
Thursday should warm well into the 70s for the weekend.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 619 PM CDT Sun Oct 16 2016

Removed chances for MVFR cigs as guidance has backed away
somewhat, but kept SCT for later this evening and overnight. Did
add LLWS as winds increase near 45kts just under the inversion
overnight. This mixes out quickly in the morning and have gusty
south winds for Monday.




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