952
FXUS63 KTOP 072335
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
635 PM CDT Fri Jun 7 2024

.KEY MESSAGES...

- Severe storms with damaging winds around 70 mph and very heavy
  rainfall are expected mainly across northern KS tonight.

- Another round of storms with heavy rain are likely (60 to 70
  percent) across east central Kansas Saturday night.

&&

.DISCUSSION...
Issued at 240 PM CDT Fri Jun 7 2024

19Z water vapor imagery showed a weak disturbance moving
through central KS with a line of elevated convection. A
shortwave was moving out into the northern plains as well.
Surface obs have shown a strengthening trough of low pressure in
the lee of the central rockies. This has allowed good moisture
advection through western KS with dewpoints increasing into the
middle and upper 60s.

Don`t see what would cause the band of elevated showers to fall
apart at this point, except that they may lose some of the better
moisture advection as they continue east. Additionally there is
higher levels of surface based CIN over eastern KS which may cause
the line to weaken as they move east. So have bumped up POPs with
coverage wording for the rest of this afternoon. Still looks like
the main threat for thunderstorms will impact the forecast area
overnight. The shortwave moving into the northern plains is sparking
convection across northern NEB. This is expected to be the
beginnings of an MCS later tonight and most guidance shows the nose
of the low level jet and strongest theta-e advection focused over
far northeast KS. There may still be some storms develop within the
warm air advection pattern ahead of the MCS, so have POPs ranging
from chance across the southern counties to categorical over
northeast KS. Forecast soundings show elevated CAPE values
increasing up to around 2000 J/kg thanks to the strong moisture
advection and there 18Z HRRR is projecting to potential for wind
gusts over 70 MPH with the MCS as it moves into northern KS. And
deep layer shear will be strong enough that some supercell structure
could allow for some large hail for a discrete storm or end of a
line segment. PWs increase to over 2 inches so the storms will
likely have heavy rain. The MCS is expected to remain progressive
enough that rain totals should still be manageable with respect to
flash flooding. This activity should exit east of the forecast area
by daybreak Saturday with some residual cloud cover hanging around.

Outflow from the MCS is progged to stall out across southern KS with
an 850MB boundary setting up across east central KS. It still
appears this will be a focus for renewed thunderstorms development
Saturday evening. However the low level jet is not nearly as strong
and veered more to the southwest. Still there is very high moisture
pooling along the boundary and convection that does form will be
capable of heavy rainfall. Fortunately this looks to mainly fall
south of tonight`s heavy rain. Models show strong instability along
this boundary and 0-6km shear is forecast to be 40KT to 50KT. So
there will be a risk for severe storms. If the low level jet was
stronger, there would be better confidence in severe storms. This
activity could linger into Sunday morning.

For Monday weak surface ridging and some dryer air look to give a
break from the convection with afternoon temps in the middle 70s to
around 80. Another shortwave within the northwest flow may spark
some showers and storms on Tuesday, but the weak surface ridge is
progged to still be over the area so moisture quality is instability
are questionable at this point. Models show mid level ridging
amplifying over the southern Rockies through the second half of next
week. This would favor hotter temperatures with POPs generally less
than 30 percent.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 622 PM CDT Fri Jun 7 2024

The primary concern this period continues to focus on the
arrival time of an overnight storms complex impacting the
terminals. Have made slight adjustments to the going forecast
and the eventual improving conditions after the storms move
through. Still uncertain how fast storms move through the
terminals so have left a tempo group for now. As storms become
more organized and track toward the area, updates will be made
to arrival time frames.

&&

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

&&

$$

DISCUSSION...Wolters
AVIATION...Drake