737
FXUS63 KTOP 291935
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
235 PM CDT Wed May 29 2024

.KEY MESSAGES...

- Any isolated thunderstorms this afternoon are forecast to
  dissipate by early evening.

- There is a 50 to 70 percent chance of showers and storms
  Thursday and into Friday morning, a few of which could be
  strong.

- The weather is forecast to begin feeling a little more like
  summer this weekend and into next week.

&&

.DISCUSSION...
Issued at 235 PM CDT Wed May 29 2024

19Z water vapor imagery showed a shortwave ridge over the
central plains with some convection developing off the higher
terrain of CO. Further upstream was an upper trough from British
Columbia into the Great Basin. Surface obs showed high pressure
over the middle MO river valley weakening with southerly return
flow increasing through the southern plains and central high
plains.

Late this afternoon, an isolated thunderstorms may develop within an
instability axis associated with the low level moisture return. This
is seen with the CU field that has formed from southeast KS through
central KS. The CAMs have shown isolated updrafts developing fairly
consistently but having confidence in a specific location where the
storm may be is low. Some modest instability around 1500 J/kg may
allow for a stronger updraft, but effective shear is expected to
remain marginal. So will need to keep an eye on this, but think
chances for severe convection remain limited. Much of this activity
should be diurnally driven and chances for precip are forecast
to diminish shortly after 6 or 7 pm.

For Thursday and Friday, the forecast appears to be a little more
nuanced and driven more by mesoscale features. The main question is
whether there will be forcing for vertical motion impacting the area
Thursday night. One idea has a shortwave trough moving across
northeast KS with widespread QPF over the area. The second idea is
for an MCV to develop across southwestern KS Thursday afternoon and
dive to the south and east of the forecast area with little QPF over
the forecast area. Overall think there will be showers and
thunderstorms Thursday and Thursday night, but they may be a little
more hit or miss. Have POPs increasing from west to east through the
day for any convection that forms along the high plains tonight and
propagates east. For Thursday night, have limited POPs to 70 percent
given the uncertainty in the evolution of the mesoscale environment.
As for the potential for severe weather, there could be some
moderate instability develop by the afternoon if morning precipition
dissipates and the boundary layer is allowed to warm. Flow is
generally weak and models generally show 0-6km bulk shear between 20
and 40 knots. So there is some chance for a few intense updrafts in
the afternoon and evening. But a lot of ingredients will need to
line up for an organized severe weather risk. Have held onto some
higher POPs into Friday morning as models show some potential for
either a shortwave or MCV to remain in the area of eastern KS
through the morning. Increased cloud cover is expected to keep highs
generally in the middle 70s for Thursday and Friday.

For Saturday through Tuesday, models show split flow persisting with
the forecast area generally between the northern and southern
streams. There is some potential for relatively weak perturbations
within the pattern to affect our weather any given day. Given the
lower predictability of the pattern, have kept the NBM forecast with
a broad brush of chance POPs. Operational models show warmer air
advecting north with time. So highs trend warmer through the weekend
and into next week feeling a little more like summer.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1151 AM CDT Wed May 29 2024

There may be a diurnally driven shower or two this afternoon,
but activity is expected to remain isolated with probabilities
of impacting a terminal around 10 percent. Chances for TS will
increasing through Thursday. At this time, CAMs keep the
activity west of MHK through 18Z. So will keep a dry forecast.
There could be some stratus advect in from the south. But this
is not a consensus among the models and probabilities for CIGs
below 3 KFT only ramp up after 12Z. Will let later shifts
reevaluate the potential for low clouds.

&&

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

&&

$$

DISCUSSION...Wolters
AVIATION...Wolters