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000
FXUS63 KTOP 151811
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
111 PM CDT Mon Apr 15 2024

.KEY MESSAGES...

- Severe storms possible Tonight through Tuesday morning, with
  large hail and damaging wind the primary hazards. A tornado
  can`t be ruled out from late Monday night into early Tuesday
  morning until the dryline shifts east of the area.

- Strong southerly winds will be around advisory levels Tonight,
  and southwesterly winds may exceed advisory levels on Tuesday
  afternoon.

- Warm temperatures through Tuesday, then cooling back below
  seasonal norms by the end of the week.

&&

.DISCUSSION...
Issued at 349 AM CDT Mon Apr 15 2024

Early this morning an amplified upper trough was located across the
Great Basin and Southwestern US. A down stream H5 ridge was
located across the eastern portions of the southern Plains. An
upper trough was shifting east across New England.

The surface observations showed a lee cyclone deepening across
eastern CO, with a lee trough axis extending southward across the
southern high Plains. A warm front was located from the surface low
east-southeast across central KS.

Today through Tuesday:

The upper low will translate east across the central Rockies into
the high Plains of CO by 00Z TUE. The surface warm front will lift
northward into southern NE and north central MO through the
afternoon hours. An EML will overspread eastern KS this afternoon and
increase the CAP. Most CAMs do not show any organized convection
ahead of the EML and warm front. The HREF ensembles show less then a
a 20 percent chance of showers or thunderstorms this afternoon
across the CWA. I kept a 20 PoP in the forecast, in case an
elevated shower or storm were to develop , These storms will
intensify this evening across NE and north central MO but will
shift to the northeast away from the CWA. Some of the forecast
soundings for this afternoon show about 800-1100 J/KG of
elevated CAPE but updrafts will struggle to develop as the EML
overspreads eastern KS. So, I`m not expecting any severe
thunderstorms this afternoon or into the evening hours. South-
southeast winds will increase across the CWA to 15 to 30 MPH
with gusts up to 30 to 40 MPH. The western counties may come
close to reaching wind advisory but it looked a bit too marginal
to issue a wind advisory for this afternoon. Tonight, if the
PBL remains mixed and the LLJ increased to 50 KTS, then a wind
advisory may be needed for most of the central and western
counties of the CWA. I`ll let the day shift re-evaluate to see
how mixed the boundary layer will be after sunset. Highs will
reach the mid to upper 80s and there will be some mid-level
clouds across the area Today.

Tonight, the upper low will move east to the KS/CO border and an 85
KT H5 jet max will round the upper low and pivot northeast into
central KS.  The surface dryline will shift east into west central
KS. Several CAMs now show initiation of surface based convection
along the dryline during the mid and late evening hours. Given the
strong low-level shear, with curved hodographs, and MLCAPE of 1400-
1800 J/KG. These storms will quickly become severe and if they
remain discrete the probability is high for supercell thunderstorms
with all hazards possible. These storm will be moving to the
northeast at 40 to 50 MPH. These supercell thunderstorms may move
into north central KS around midnight, and then shift northeast into
southern NE. Some of the CAMS show the storms weakening a bit after
7Z. Before the dryline pushes farther east into the central CWA
around 10Z, where surface convergence will increase for new
storms to develop along the dryline across the central counties
of the CWA. If these storms are surface based then the
supercells moving northeast across east central and northeast KS
may produce not only large hail, damaging wind gusts but
perhaps a few tornadoes. However, if these storms are slightly
elevated the tornado threat would be quite low. Also, the HREF
ensembles members do show the instability decreasing across east
central KS during the early morning hours of Tuesday but the
hodographs are nice and curved which would provide for stream-
wise horizontal vorticity ingested into the updrafts, which
would intensify the updrafts as the mid and low level
mesocyclones intensify. Something to watch closely during the
pre dawn hours of Tuesday. The dryline/Pacific front should move
east of the CWA by 15Z, brining an end to the threat of severe
thunderstorms.

Most CAMs and deterministic models lift the upper low northeast
across east central NE by 00Z WED. The richer low-level moisture
will be east of the dryline in west central MO, which will curl
back north-northwest to the surface low over southeast NE. The
low-level winds will be veered across the CWA. I cannot rule
out a strong thunderstorms redeveloping across the eastern
counties of the CWA during the afternoon hours. But the ensemble
mean of surface based CAPE will only be 300 to 600 J/KG. The
southwest surface winds will increase to 25 to 35 MPH with gusts
to 40 to 45 MPH. A wind advisory will be needed Tuesday
afternoon. Also, there may be a high to very high fire danger
despite the rapid green-up taking place in the prairie grasses.

Tuesday night through Monday:

An upper level trough will dig southeast across the northern Plains
and upper Midwest and amplify. This will bring a stronger cold front
southward across the CWA Wednesday night into Thursday morning.
There may be showers and thunderstorms developing ahead of the
front and lingering behind the front into Thursday morning.

Strong CAA will build a surface ridge southward across the Plains.
Expect much cooler temperatures Friday into the weekend. Highs will
only reach into the 50s Friday and Saturday. Then highs will
moderate a bit back into the 60s Sunday and Monday. Looks like
we will warm back up by the middle of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 111 PM CDT Mon Apr 15 2024

Stratus with the low level moisture advection continues to mix
out. With the better forcing for vertical motion remaining west
this afternoon, think VFR conditions will prevail into the
evening. As the boundary layer cools and forcing increases
overnight, MVFR CIGS are expected to return. Have timed TS based
on the latest CAMs. And a strong pressure gradient will keep
turbulent mixing in the boundary layer throughout the night and
into Tuesday morning.

&&

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

&&

$$

DISCUSSION...
AVIATION...Wolters