Flash Flood Warning 72, NWS Topeka, KS

Area Forecast Discussion
National Weather Service Topeka KS
627 PM CDT Tue Sep 24 2019

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday)
Issued at 324 PM CDT Tue Sep 24 2019

Persistent mid-level cloud cover into the early afternoon hours has
kept a complicated forecast for the rest of the afternoon and this
evening. Uncertainty remains as to whether or not storms will
develop over our CWA, but some activity has already begun to fire in
southwestern KS.

A mid-level shortwave trough and strong upper-level jet are moving
through the northern and central plains with a surface cold front
extending from southern MN through central NE into western KS.
Isentropic lift on the warm side of the front has kept most of our
area under mainly cloudy skies with a few peeks of sunshine,
although this has shown a trend of scattering out in the last couple
of hours. As a result, instability remains lower in east central KS
compared to the central part of the state. That being said, however,
a few storms have developed in southwest KS ahead of the surface
boundary. Moisture advection has also brought dew points into the
low 70s across the area with a dryline in place near the frontal
boundary in western KS. Current mesoanalysis in north central KS
shows MLCAPE between 2500-3500 J/kg and effective bulk shear between
35-45 kts, with forecast soundings showing minimal CIN through the
afternoon. With this in mind, the potential still exists for strong
to severe storms to develop in our CWA during the late
afternoon/early evening, particularly in central KS. Primary threats
would be large hail and damaging wind. However, the best forcing
remains to our northeast associated with the shortwave trough and
upper jet, and to our southwest associated with the surface front.
CAMs today have consistently shown storm initiation in both of these
areas while struggling to develop storms in north central KS and
maintain their strength as they move east. This keeps our CWA
between the two clusters, but if we do see any storms tonight,
chances are best in the southwest part of our area, which borders
the current Severe Thunderstorm Watch in effect until 03Z tonight.

The threat for severe weather diminishes late tonight, and generally
quiet weather is expected overnight aside from a small chance for
isolated showers and weak storms in the southern part of the CWA.
Wednesday will see the frontal boundary push south into east central
KS, and we may see some redevelopment of storms along that boundary
during the late afternoon and evening once again. However, the
placement of the front could put this activity entirely south of the
area in southeast KS. Confidence on this will be greater once we see
where the front sets up tomorrow.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 324 PM CDT Tue Sep 24 2019

Wednesday night, the surface front will become stationary along the
KS OK border. The isentropic lift north of the front will weaken as
850mb winds veer more to the west. The better chance for showers and
elevated thunderstorms will be across the southeast counties. An
amplified upper level trough will move east from the northern and
central Plains into the Great Lakes States

Thursday through Thursday night, Looks dry through most of the day
as the zonal flow regime continues across the northern and central
Plains. The upper trough across the Great Lakes will lift northeast
across New England. A lee surface trough will deepen through the day
and southerly low-level flow will advect deeper moisture northward
across central KS and southeast KS. The better surface convergence
will be along the stationary boundary across northern OK and
southern KS and should remain south of the CWA. A southern stream
upper level ridge, downstream from a southern stream upper level
trough across southeast AZ/southwest NM, will amplify and probably keep
the CWA dry, even with some weak isentropic lift as richer
moisture advects northward across the area. The better WAA will be
across the upper Midwest Thursday night.

Friday through Saturday night, A deep upper level trough will
move into the western US. As the upper level trough moves into
the western US it will kick the southern stream H5 trough
northeast across the Plains Friday night into Saturday night.
Meanwhile, a surface front will slowly drift south across the CWA
Friday afternoon and become stationary and may move back as a warm
front Friday night into Saturday. The combination of DCVA ahead
of the H5 trough lifting northeast across the central Plains and
surface convergence along the boundary, plus isentropic lift north
of the boundary will provide chances for scattered to numerous
showers and thunderstorms through the period. The environment may
become favorable for strong to severe thunderstorms Friday
afternoon and evening across northeast and east central KS, and
then possibly again Saturday afternoon into Saturday evening given
stronger vertical wind shear, moderate instability and rich
moisture. Saturday afternoon severe weather hazard may depend on
how the atmosphere recovers from morning Thunderstorms. There will
also be the potential for heavy rainfall which may cause some
flooding Friday evening through Saturday night.

Sunday through Tuesday, The upper level trough across the western US
will remain nearly stationary. Most of KS will be in the warm sector
and the best chances for Thunderstorms Sunday through Monday will be
along the lee sfc trough axis/dryline across western KS. I cannot
rule out minor perturbations, embedded within the southwesterly
upper level flow, moving northeast across eastern KS Sunday
through Monday, which may provide a chance for isolated to
scattered thunderstorms. On Tuesday a s surface front will slowly
move southeast across the northern and western counties of the CWA
which may increase shower and thunderstorm chances Tuesday
afternoon into Tuesday evening.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 623 PM CDT Tue Sep 24 2019

Short term concern is the eastward progression of developing
convection west of the terminals. Model guidance providing low
confidence on progression and impact, but am estimating arrival
time at terminals based on current direction and movement. Models
hinting at the possibility of IFR conditions after 10Z along the
cold front as it passes through. Will leave IFR determinations to
06Z forecast after line of convection moves through.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...Picha
LONG TERM...Gargan
AVIATION...Byrne

Hazardous Weather Outlook
National Weather Service Topeka KS
446 PM CDT Tue Sep 24 2019

KSZ008>012-020>024-026-034>040-054>056-058-059-252200-
Republic-Washington-Marshall-Nemaha-Brown-Cloud-Clay-Riley-
Pottawatomie-Jackson-Jefferson-Ottawa-Dickinson-Geary-Morris-
Wabaunsee-Shawnee-Douglas-Lyon-Osage-Franklin-Coffey-Anderson-
446 PM CDT Tue Sep 24 2019

This hazardous weather outlook is for east central...north
central and northeast Kansas.

.DAY ONE...Tonight.

Severe thunderstorms are possible this evening mainly over north
central KS. Large hail and damaging winds appear to be the main
hazards. However, an isolated tornado can't be ruled out.

Flooding on the Big Blue River near Blue Rapids continues.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

The probability for widespread hazardous weather is low at this
time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

&&

More detailed information can be accessed at...
http://www.weather.gov/top/sitrep

Special Weather Statement
National Weather Service Topeka KS
524 PM CDT Tue Sep 24 2019

KSZ008-020-242330-
Republic-Cloud-
524 PM CDT Tue Sep 24 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL REPUBLIC AND
NORTHWESTERN CLOUD COUNTIES UNTIL 630 PM CDT...

At 524 PM CDT, Doppler radar was tracking a strong thunderstorm near
Jamestown, moving northeast at 20 mph.

Pea size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Concordia, Belleville, Jamestown and Norway.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3984 9762 3961 9745 3954 9784 3964 9792
TIME...MOT...LOC 2224Z 240DEG 17KT 3961 9781

Baerg

Special Weather Statement
National Weather Service Topeka KS
549 PM CDT Tue Sep 24 2019

KSZ020-034-242345-
Cloud-Ottawa-
549 PM CDT Tue Sep 24 2019

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN OTTAWA AND SOUTHERN
CLOUD COUNTIES UNTIL 645 PM CDT...

At 549 PM CDT, Doppler radar was tracking a strong thunderstorm near
Barnard, moving east at 35 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Miltonvale, Glasco, Delphos, Aurora and Ada.

A Severe Thunderstorm Watch remains in effect until midnight CDT for
north central Kansas.

LAT...LON 3939 9793 3950 9752 3916 9738 3912 9793
TIME...MOT...LOC 2249Z 251DEG 31KT 3922 9806

Baerg