853
FXUS63 KTOP 172323
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
623 PM CDT Fri May 17 2024

.KEY MESSAGES...

- Isolated, pop-up thunderstorms cannot be ruled out Saturday
afternoon as a weak front settles into the area.

- Scattered severe storms are possible over portions of north
central and northeast Kansas Sunday late afternoon and evening.

- Temperatures heat up to around 90 degrees area wide this weekend
into early next week.

&&

.DISCUSSION...
Issued at 222 PM CDT Fri May 17 2024

Broad northwesterly flow aloft passing through the central plains
this afternoon while the open shortwave trough axis resides over
northern Texas. A very weak perturbation noted sliding through the
state may spark an isolated storm in southeast Kansas, however last
several runs of the CAMs have centered convection initiating along a
a residual boundary towards southern MO so confidence remains low
for adding pops this afternoon.  The aforementioned shortwave trough
shifts east of the region this evening, as heights build in on
Saturday. The frontal boundary arrives from the northwest, bisecting
the CWA from southwest to northeast by late afternoon. While mid
level winds are light with minimal upper level dynamics in play,
weak low level convergence in conjunction with Sfc CAPE values
in upwards of 2000 J/KG and weakening inhibition are present by
late afternoon. 12Z CAMs remain consistent in isolated
convection developing along the boundary, however with effective
bulk shear in upwards of 25 kts, main hazard would be brief,
gusty winds directly underneath the updraft before quickly
dissipating shortly after sunset.

As the next upper trough arrives into the western high plains
Saturday evening, models are progged to develop an MCS across
northwest KS, potentially impacting far northern Kansas late
Saturday night into Sunday morning. These storms should weaken
by the time they reach our area so severe weather concerns are
low. They may however impact additional CI in the afternoon,
altering the environment and creating a more stable airmass.

Focus turns to the severe potential late afternoon and evening
Sunday as strong southerly flow lifts sfc dewpoints from the middle
60s into eastern Kansas. While the upper trough vort max
approaching from the west is not particularly poignant, strong
sfc heating with highs near 90 degrees should aid in steepening
low level lapse rates in advance of a dryline setup over central
Kansas. Assuming the capping inversion is able to erode which
remains in question, scattered severe storms may develop in
vicinity of the dryline, entering into northeast Kansas by late
afternoon and early evening. Large hail and damaging wind gusts
would be the primary hazards at this point, especially given the
slightly higher cloud bases and lack of strong low level
moisture advection. Storms appear to cluster into an MCS
overnight into Monday morning with some lingering activity
anticipated over far eastern Kansas. Uncertainty in convection
Monday afternoon and evening is high over northeast Kansas as
the inverted sfc trough axis stretches into western KS,
effectively forcing a warm front northward into southern NE by
the evening. Orientation of the upper trough axis would also
suggest severe storm activity remains north of the CWA late
Monday evening, depending upon where the frontal boundary ends
up.

On Tuesday afternoon, the upper trough axis ejects into the
northern plains, forcing a strong cold front into the plains.
Timing of the wave and subsequent position of the front by peak
heating varies widely with ensemble guidance. For instance,
latest NBM spread of QPF Tuesday evening varies from 0 to 0.70
of rainfall along and east of highway 75. If storms were to
impact the area on Tuesday, they would be severe so it is
prudent to continue monitor model trends this weekend. Forecast
for now maintains modest pops through Wednesday, but do not
anticipate a washout or numerous severe storms at this point.
After highs in the 80s through Tuesday, a welcome relief from
the heat arrives Wednesday and Thursday. Highs are generally in
the middle 70s while overnight lows settle in the lower 50s.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 623 PM CDT Fri May 17 2024

VFR conditions expected through the period. Winds remain light
from the SSW before switching to the north near the end or just
after this TAF period. There is a chance for few pop-up storms
near terminals Saturday afternoon/evening, but confidence is
too low for inclusion.

&&

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

&&

$$

DISCUSSION...Prieto
AVIATION...Flanagan