182
FXUS63 KTOP 281956
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
256 PM CDT Fri Jun 28 2024

.KEY MESSAGES...

- Heat Advisory continues until 7pm for portions of central and east
central KS, with heat indices around 105 degrees.

- Isolated thunderstorms in northeast KS late this afternoon into
this evening could be severe with damaging wind, hail, a tornado,
and brief heavy rain all possible.

- Additional thunderstorms are possible towards central KS after
midnight tonight with damaging wind, although confidence is lower in
this scenario.

- Up and down temperatures with off and on thunderstorm chances
  for much of next week.

&&

.DISCUSSION...
Issued at 255 PM CDT Fri Jun 28 2024

Surface cold front has started to move into north central KS early
this afternoon, with the associated trough axis stretching up
through eastern NE and western IA. 19Z water vapor imagery shows the
upper low spinning well north of us in eastern MT. Meanwhile, gusty
southerly winds and a slowly weakening LLJ have been pumping low-
level warmth and moisture into the area today. Subsidence behind
this morning`s system has allowed skies to clear with heat indices
already in the low 100s in a few locations, so will keep the Heat
Advisory going until 7pm.

The main focus revolves around this evening`s storm chances and
associated severe weather potential. The latest guidance suggests
that storms look rather isolated late this afternoon into this
evening with upper support being displaced well north of the area,
but think this time frame presents the greater severe risk compared
to the next chance later tonight into the overnight hours. The
atmosphere should continue to become more unstable the rest of this
afternoon, with the higher dew points and therefore highest
instability (3000-4000+ J/kg) concentrated over far northeast KS.
Think 21-00Z is the main time frame to watch for initiation in this
same area where convergence along the frontal boundary should be the
strongest. This instability plus 30-40 kt of deep-layer shear should
be sufficient for supercells. The tornado threat is more uncertain
and looks to be quite localized, as forecast soundings and
hodographs show the best low-level turning near the frontal boundary
with a noticeable decrease in low-level shear and SRH just a short
distance away from the boundary. However, this threat should not be
ignored as locations near the boundary should see the best lift.
Additionally, any storms that develop in this area during this time
could produce locally heavy rainfall with Pwat above 2". The
moisture axis looks to be focused in far eastern KS into MO for much
of this evening before being pushed south into Saturday morning.

The later evening hours should see a bit of a break before the next
possible round of thunderstorms. A cluster of storms looks to
develop in eastern CO and move through western KS, which could move
into portions of central KS overnight, although confidence is not
high on a widespread severe risk as CAMs largely show these
weakening as they move into our area. Western KS has a much more
well-mixed BL to support damaging wind in that environment, whereas
forecast soundings in north central KS become less supportive of
that potential as we get into the late night hours. Still, storms
that manage to maintain themselves as they move eastward could
present a damaging wind threat with locally heavy rainfall. Any
lingering storms should taper off throughout the morning hours
Saturday.

Will need to continue to monitor where the frontal boundary sets up
Saturday to delineate the areas for highest storm chances and
associated severe risks in the afternoon and evening. The trend
today has pushed the boundary a little further south, with much of
the guidance placing it just south of the CWA by mid to late
afternoon. Thinking locations along/south of I-35 are the main areas
to watch if the boundary were to set up further north than currently
forecast. Damaging wind and perhaps small hail would be the main
hazards with storms.

Outside of rain/storms, temperatures look much more manageable
through the weekend with highs in the 80s to near 90 Saturday, and
mid 70s to low 80s Sunday. Unfortunately, the heat does look to make
a return for the early part of the next work week as the upper ridge
to our south expands northward, resulting in hot and humid
conditions again for Monday and Tuesday. There are some periodic
thunderstorm chances in the meantime, although the best chances look
to be Tuesday night into Wednesday when the next front moves through
the area.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1237 PM CDT Fri Jun 28 2024

South/southwest winds will continue to gust to 20-30 kt at
times this afternoon ahead of an approaching cold front.
Thunderstorms late this afternoon into the evening look to be
isolated, so have opted to leave mention out of TAFs with
confidence in them impacting terminals being too low. However,
if one develops, there could be some brief heavy rain with all
severe hazards possible. Cold front moves through and shifts
winds to the north/northwest late this evening and overnight.
Much of the latest guidance has the next round of storms
weakening as it moves out of western KS, so confidence that
they`ll make it this far east is even lower than the first
round. VFR conditions are forecast overall.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT this evening for KSZ021-KSZ022-
KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ054-KSZ055-KSZ058.

&&

$$

DISCUSSION...Picha
AVIATION...Picha