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000
FXUS63 KTOP 160541
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1241 AM CDT Tue Apr 16 2024

.KEY MESSAGES...

- Severe thunderstorms with potentially a tornado or two could
  impact the region overnight tonight.

- The risk for severe weather late in the evening and after
  midnight makes for a greater threat while people sleep.

- Strong southwest winds could gust to near 40 mph across east
  central Kansas through the day Tuesday.

&&

.DISCUSSION...
Issued at 245 PM CDT Mon Apr 15 2024

19Z water vapor imagery showed a closed upper low over the four
corners region with a tropical fetch of moisture streaming into
the central plains from the Gulf of California. Surface obs
show dewpoints in the middle 60s almost entirely through the
forecast area advecting into southern NEB.

For tonight and into Tuesday morning, models show the best forcing
for vertical motion moving across the forecast area between 06 and
12Z. CAPE values are progged to be between 2000 and 3000 J/kg as 0-
6km bulk shear increases to near 60KT. SO the environment looks to
be favorable for severe weather. There is a caveat though mainly
around the forecast hodographs showing weak winds around 700MB
during the overnight period. This weakness in the wind field causes
a looping inflection in the hodograph across east central and
northeast KS suggesting that there could be disruptions in the
updraft circulations making it difficult for individual storms to
maintain discrete identity. However a well mixed boundary layer will
increase the potential for storms to remain nearly rooted in the
boundary layer with 0-1km helicity of 300 to 400 m2/s2 and a treat
for tornadoes well after midnight tonight. I think the inflection in
the hodograph is why the CAMs are showing more of a broken line of
storms towards daybreak through northeast KS instead of several
supercell storms. The expectation is for severe storms to develop
odd the dryline in western KS this evening and move towards the
north central KS counties. These storms appear to have the greatest
potential for tornado as the inflection in the forecast hodographs
is much less pronounced. Think the potential for discrete storms
decreases the further east storms move, but I am not willing to
discount a tornado or two given the strong shear and CAPE
environment. The dryline/Pacific front is expected to push east of
the forecast area mid-morning Tuesday with the main severe weather
risk pushing east as well.

Tuesday afternoon and evening, models have some warp around moisture
within the closed low moving across north central KS. Instability is
progged to be much lower with forecast soundings suggesting deep
mixing of the boundary layer and storms being high based. There may
be some small hail if storms redevelop within the cold core low. The
deep mixing noted in the forecast soundings also points to the
potential for wind advisory level winds across east central KS
through the day Tuesday. There was some discussion about issuing a
wind advisory for Tuesday but the consensus was to let later shifts
take a look at the 00z data.

POPs have increased for Thursday as a cold front pushes through the
forecast area. There doesn`t appear to be a strong shortwave noted
in the deterministic models, but the NAM and GFS do show good mid
level frontogenesis and q vector convergence for vertical motion. So
think the increased POPs are valid. Confidence in the small POPs
after Thursday are low given the front should be well southeast of
the area by then.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1234 AM CDT Tue Apr 16 2024

A line of showers and storms may move across the terminals after
9Z and last for an hour or two. There may be some gusty winds if
a line of storms develops. There may be some light showers
between 13Z and 15Z. MVFR ceilings will drop to around 1300 feet
through the early morning hours. Once the front moves through
after 14Z, the clouds will clear. Southwest to west winds will
increase through the morning and increase to 18 to 24 KTS with
some gusts up to 35 KTS during the late morning and early
afternoon hours.

&&

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

&&

$$

DISCUSSION...Wolters
AVIATION...Gargan