Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 190441
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1141 PM CDT Fri Jun 18 2021

...Update to aviation forecast discussion...

.DISCUSSION...
Issued at 323 PM CDT Fri Jun 18 2021

The upper high remains in control of the southwestern states with
very warm mid and upper level air sprawled east across the central
and southern Plains. A stationary front lingers just north of Kansas
with occasional very high-based convection to its north. A shortwave
was rotating southeast out of eastern North Dakota on recent water
vapor imagery. Local early afternoon heat index values are in the
upper 90s to around 102.

The latter wave will help induce another low-level jet tonight with
decent convergence to the northeast and likely spark more robust
convection in eastern Nebraska and southwestern Iowa after sunset.
Have kept small precip chances in the far northeast in case the jet
can allow this build farther southwest. Some high cloud will spill
over the ridge overnight though winds looks a bit weaker and expect
lows slightly slower as a result. Topeka`s temp by 1 AM CDT (12 AM
LST) may stay above 81 which would allow today`s record highest
minimum temperature to be set (previous record was 80 set in 1953).

The front may sag southeast into northeast Kansas Saturday but
capping for surface-based convection continues to look too strong
and convergence is week. Guidance is in good agreement on slight
cooling at 850 mb and will go along with this idea for temps and
heat index values a bit lower, with HI values as high as 102 in some
locations.

Precipitation chances increase somewhat late Saturday night as
convection from a shortwave trough moving through the central
Rockies attempts to reach central Kansas. Although mid-levels cool a
bit, have doubts much of this will persist this far east. A longer
wavelength trough digs into the northern Plains Saturday night into
Sunday though some MLCIN continues to be in place as the associated
cold front moves in. Expect better precip chances to be in the
evening into early Monday. Heat index values Sunday return to the
upper 90s to around 102.

Much cooler temps on track for Monday and Tuesday (Monday`s 850 mb
values around 12 C colder than Sunday) with dewpoints possibly below
50 F. Ridging aloft rebuilds in the mid to late week for warming
temps though the flow character aloft differs. There should be at
least some potential for WAA convection at times though hard to
differentiate when this may be. Went along with NBM PoPs, though the
persistent chance values could be too aggressive.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1137 PM CDT Fri Jun 18 2021

VFR conditions continue for the 06Z TAF period. LLWS is occurring
at sites tonight but should subside after sunrise Saturday. A
surface boundary will drop southward to near airports by midday,
causing wind directions to initially veer slightly to the west-
southwest, then back to the south during the afternoon. Speeds
should generally be below 10 kts.

&&

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

$$

DISCUSSION...65
AVIATION...Teefey


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