089
FXUS63 KTOP 131047
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
547 AM CDT Tue Aug 13 2024

.KEY MESSAGES...

- An MCS expected to move into the area by early this morning with
showers and storms through much of the morning, especially along and
south of I-70.

- Another round of nocturnal storms this evening and overnight may
be possible focused mainly over northeastern Kansas areas.

- Hot and humid during the day Wednesday ahead of the arrival of a
cold front into the evening. Some areas may reach advisory levels
mainly along and south of I-70.

- A cold front pushes through Wednesday night giving the chance for
storms to form into the evening time frame with near normal
temperatures to follow.

&&

.DISCUSSION...
Issued at 346 AM CDT Tue Aug 13 2024

Currently, the upper air pattern across the CONUS is in transition.
The mean Westerlies reside north of the area. The trough over the
northeastern CONUS has begun to lift northeast which as allowed for
the western CONUS ridge to broaden and move east. The apex of the
mid to upper level ridge is now along the front range of the
Rockies. Monsoonal moisture is still being transported into the
central Rockies and around the ridge and ultimately across the
central Plains. Near the surface, a considerable increase in low
level moisture has taken place over the past couple of days with
dewpoints around the low to mid 70s across southern portions Kansas.
An inverted surface trough is in place generally from the TX
panhandle region into south central and into northeastern Kansas.
Storms that developed earlier during peak heating over southeastern
Colorado have organized into a weak MCS and continue to advance east
northeast into southwestern and west central Kansas.

Early this morning, expecting the mean flow to help steer the MCS
into the southern portions of the local area. Have maintained
highest POPs around sunrise into mid morning over central into east
central KS areas. As of this hour, storms haven`t trended all that
severe with warnings continuing to drop off as the eastward
advancement takes place into only a marginally severe environment. A
couple of notable clusters of storms continue regardless. Still
expect that may be an opportunity for a marginally severe storm into
early morning across the area but this chance looks low when looking
at CSU machine learning probs with less than a 10-15% chance over
southern areas. A stable low level layer continues to set up with
DCAPE continuing to fall. Would expect heavy rain at this point to
be the primary concern with morning storms as a deep moist forecast
sounding profile appears to suggest little in the way of dry air.
Rainfall HREF probability matched mean values still range from 2-3
inches this morning.

Into tonight and Wednesday morning, an embedded shortwave amplifies
as it ejects from the Rockies into northern central Plains through
Nebraska. The focus for strongest ascent looks to be north of the
area but isentropic ascent within the warm moist flow transport
across the area may provide an opportunity for a band of heavy rain
to set up over northeastern portions of Kansas into far east central
areas. The high PW airmass should allow for efficient rainfall
within this area, so heavy rain could again become a concern. The
good thing is this is likely focused away from the area that may see
the heaviest rainfall into this morning. Flash Flood guidance is
still in the 2-3 inch range over northeastern KS areas. If storms
tend to remain anchored in one general area and training effects set
up due to any backbuilding then chances for flooding would go up
quickly. However, trends in CAM guidance is suggesting storms would
be focused northeast of the forecast area (confidence in these
models has not been high recently, unfortunately). Given that, have
kept northeastern Kansas areas into 60 percent chance range.

As the wave moves through the Plains, it is forecast to deepen
resulting in advection of modified cool air being pulled into the
Plains. This helps push a modified cold front toward the area. Ahead
of this, with dewpoints still into the 70s, should experience near
advisory level heat during the day Wednesday generally along and
south of I-70. With strong capping forecast to be in place, storms
into late Wednesday afternoon and evening may have a hard time
developing. Could see a few isolated to scattered storms that
produce hail and wind into the evening hours along with heavy rain
once again over portions of the area.

Once this moves through, back to a northwest flow component into the
weekend and generally cooler temperatures overall into the 80s at
least through the upcoming weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 523 AM CDT Tue Aug 13 2024

Marginal VFR conditions for much of the early morning with brief
IFR conditions possible. A few thunderstorms may also briefly
impact the terminals but mostly -SHRA looks on track with the
main line segment from the morning MCS moving south of the area.
Partial clearing may take place this afternoon before clouds
build back in and possible showers and storms again late period
but favored areas for storms overnight expected mainly northeast
of the terminals.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Drake
AVIATION...Drake