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000
FXUS63 KTOP 060906
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
406 AM CDT Thu May 6 2021

.DISCUSSION...
Issued at 359 AM CDT Thu May 6 2021

An upper level longwave trough remains in place over the eastern
half of the CONUS this morning. At the surface, a cold front moved
into northeastern KS overnight and is expected to progress
southeastward through the forecast area by about 12Z (7 AM) today.
Surface high pressure will move in behind this morning`s front.
The air mass associated with the surface ridge is drier and cool.
Even though we will see abundant sunshine this afternoon,
temperatures will struggle to reach the 70 degree mark for most of
us.

High pressure will move southeast into Arkansas tonight as lee
cyclogenesis commences east of the Colorado Rockies. A nocturnal LLJ
and resulting warm air advection pattern will develop across western
KS and OK. Elevated thunderstorms could develop on the nose of the
LLJ in central KS by the early morning hours of tomorrow. Most of
the convective allowing model solutions show that batch of
showers and storms moving into eastern KS around midday as the jet
pushes east, low level moisture increases, and isentropic ascent
becomes stronger over the area.

Another round of thunderstorms will be possible Friday night and
early Saturday with another LLJ and continued isentropic related
lift. Elevated instability and more impressive shear could lead to
some hail with this round of convection. Surface low pressure will
deepen in eastern CO during the day with an associated warm front
advancing northward into central KS. I feel that there is a
little better agreement on where that warm front will set up by
Saturday evening with GFS and NAM bringing the warm sector to
I-70. The Euro remains a little further south, consistent with
previous runs. Increasing mid-level lapse rates will lead to
growing MLCAPE values in the warm sector during the afternoon
with GFS and NAM generally showing around 1500 to 2000 J/kg as far
north of I-70 in central and eastern KS (NAM is a bit more
bullish with up to 2500 J/kg in Morris and Dickinson Counties).
Model indication of strengthening deep layer shear near and south
of the boundary, combined with aforementioned instability is
leading to increasing concern for severe weather potential. All
modes of severe weather look possible late Saturday afternoon and
evening given the parameters discussed here.

Saturday`s system pushes east of the area on Sunday, but an active
pattern will continue into next week with at least slight chances
POPs on both Monday and Tuesday. Cooler than average temperatures
remain dominate this forecast package, with the exception of those
areas that end up south of the warm front on Saturday. Otherwise,
expect highs to generally remain in the 60s until late next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1150 PM CDT Wed May 5 2021

Subtle changes to the forecast mainly delaying the arrival of the
cold front a couple of hours. Also, SHRA around the KTOP/KFOE
terminals will cause some variable winds with associated outflows.
This will subside over the next hour or two. Little in the way of
lightning and not expecting any further development. Winds still
somewhat gusty into the morning and afternoon behind the front.
Should maintain VFR CIGS through the duration. However, there may
be a very small period where CIGS are close to IFR but mainly
north of the terminals around sunrise.


&&

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

$$

DISCUSSION...Teefey
AVIATION...Drake