321 
FXUS63 KTOP 252319
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
619 PM CDT Mon Oct 25 2021

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Tuesday)
Issued at 230 PM CDT Mon Oct 25 2021

Stratus has been slow to erode under the ridge with some breaks
finally noted on vis satellite. Expect gradual decrease in clouds
through sunset with light east winds set to become southeast after
midnight as the sfc ridge quickly shifts east and low pressure
deepens across eastern CO.  

Southeast winds will increase on Tuesday as the low gradually
shifts east into west central KS by 00Z. A narrow axis of
modified Gulf moisture with sfc dewpoints around 60F should move
into central KS however the airmass across our CWA may remain
drier with dewpoints in the upper 40s to mid 50s due to the SE
component. Convective allowing models are consistent in showing
thunderstorms developing across southwest and west central KS
around 00Z within the narrow axis of low level moisture. All in
all expect conds to remain dry through 00Z Weds across the CWA.

.LONG TERM...(Tuesday night through Monday)
Issued at 230 PM CDT Mon Oct 25 2021

Intense forcing will emerge Tuesday night with the negatively
tilted trough. Expect t-storms to develop rapidly across
western/southwest KS into western OK within better low level
moisture axis. This area of convection will race northeast toward
the CWA arriving by or after midnight. All fcst soundings show a
strong inversion in place after 6z with MUCAPE of around
1000-1500j/kg and effective shear around 35-45kts. However the
wind profiles aloft/Hodographs are messy above the inversion so we
may see some version of a broken line by the time it approaches
the CWA. Some hail risk appears possible while one cannot rule out
wind given the strength of the low level wind fields however as
noted the inversion is also forecast to remain in place overnight
which could mitigate a more widespread wind risk especially as the
storms outrun the narrow moisture axis late Tues night.

What should occur is that as the intense forcing with the right
entrance region of the upper jet/divergence aloft should support
more widespread precip development toward 12z Weds and especially
through the day on Weds as the upper low closes off across OK and
deep moisture convergence organizes across central/northeast
Kansas. That will lead to widespread rain and embedded
thunderstorms through the day with more widespread rainfall
expected near the sfc/850mb trough/front. MUCAPE does diminish by
00Z thurs however the trowel/deformation zone then organizes
across some part of northeast KS to keep the rain falling into
Weds night. All told given the duration of the rain and
PWATS/forcing many areas will see anywhere from 1 to 2.5 inches of
rain over a 24 hour period.

A windy and cold day should be on tap for Thurs as the system
finally departs with showers gradually ending from west to east.
Quiet and cool weather is expected into the weekend however there
are signals that the first true Polar cold front of the year may
sweep south around Sunday into next Monday so that's something to
monitor for possible freeze conds into early next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 619 PM CDT Mon Oct 25 2021

Stratus has been eroding over the past few hours and expect it to
be out of FOE at the start of the forecast period. Expect vfr to
continue for cigs at TOP and MHK with some mvfr vsbys after 06Z at
TOP. Winds light southeast, increasing to around 14kts after 14Z,
then around 15kts with gusts to 25kts by 18Z.

&&

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

$$

SHORT TERM...Omitt
LONG TERM...Omitt
AVIATION...53