FXUS63 KTOP 300428

Area Forecast Discussion
National Weather Service Topeka KS
1128 PM CDT Tue Sep 29 2020

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday)
Issued at 359 PM CDT Tue Sep 29 2020

The forecast area remains within northwesterly flow between an
amplified trough over the eastern half of the CONUS and a ridge
expanding over the Pacific Northwest into the southwestern US. This
set-up has allowed warm temperatures to our west to advect into our
area with westerly winds at the surface and low levels, bringing our
afternoon temperatures to the upper 70s in the west and low 70s in
the east. This will give us a quiet and seasonable evening as
temperature advection becomes more neutral overnight and clear skies
allow enough radiational cooling to fall back to the low 50s by

For Wednesday, recent models suggest the cold front dropping south
from NE during the mid to late morning, which is earlier than
previous models had indicated. As such, have lowered highs a few
degrees as insolation will be fighting against CAA during the day,
so temperatures will have a harder time warming up. For now, have
highs in the low 70s near the KS/NE border and mid to upper 70s
along and south of I-70, but could see these become cooler if the
front indeed moves through the area faster.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 359 PM CDT Tue Sep 29 2020

Northwest flow continues at least through the weekend with troughing
building back to the west as additional shortwaves within the flow
dive south from Canada. CAA behind the front keeps temperatures
below normal with highs in the 60s and lows in the 30s and 40s.
Friday still looks to be the coldest morning in the extended as many
areas see mid to upper 30s, keeping the potential for areas of frost
by sunrise. Models still vary on timing and strength of the next
disturbance for Saturday, so low chance PoPs remain for showers and
perhaps a few storms, although the timing ranges from early in the
morning through the late afternoon/early evening. Winds briefly
switch to the south on Saturday before a weak boundary passes in the
afternoon, so highs only warm a couple of degrees into the 60s. The
better chance of a warm-up looks to come early next week as
amplified troughing finally pushes east and WAA returns with
increasing heights, bringing highs back to the 70s.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1123 PM CDT Tue Sep 29 2020

VFR at KTOP/KFOE/KMHK as light and VRB winds gradually veer from
the west near sunrise before the FROPA shifts northwest winds
from 15 to 18 kts sustained. Wind gusts in excess of 25 kts are
likely throughout the afternoon behind the front before weakening
aft 00Z. VFR stratus deck currently entering IA should continue
shifting southeast, remaining just east of KTOP/KFOE overnight.





NWS TOP Office Area Forecast Discussion