Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 222041
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
341 PM CDT Wed Mar 22 2017

.SHORT TERM...(This evening through Thursday)
Issued at 320 PM CDT Wed Mar 22 2017

As of Wednesday afternoon, mid-level ridging was centered over the
central plains along with a surface high across the Great Lakes
region. With the formation of the mid-level trough across the
southwest US, gulf moisture will continue to stream northward across
the forecast area. The first batch of moisture is evident with the
low stratus was pushing north into portions of the forecast area.
Areas in far northeast KS may warm a few more degrees as mostly
sunny skies should prevail through sunset. Still expected light
drizzle to develop near 06Z as isentropic lift within the 300K to
310K layer increases along with maximized low level saturation. As
the lift exits the area to the north after 12Z Thursday morning,
expect majority of drizzle to come to an end by 18Z. With overcast
skies expected, low temperatures will remain in the upper 40s
overnight. WAA will continue into Thursday, allowing high
temperatures to surge into the middle and upper 70s. Winds will
remain gusty through the period in response to leeward
cyclogenesis across eastern Colorado. A pressure gradient ~6MB
will develop Thursday, resulting in southerly winds around 15-20
MPH sustained with gusts upwards of 30 to 35 MPH. Any shower or
thunderstorm activity looks to remain west of the CWA through
Thursday evening.

.LONG TERM...(Thursday night through Wednesday)
Issued at 320 PM CDT Wed Mar 22 2017

Thursday night, An upper level trough will move east from the four
corners region into the eastern CO. Ahead of the upper trough deeper
moisture will advect northward across central and eastern KS. The
resulting isentropic lift will cause showers and a few elevated
thunderstorms to develop through the night. Overnight lows will only
drop into the upper 50s to lower 60s given south winds at 15 to 20
MPH and dewpoints increasing through the 40s into the 50s.

Friday through Friday night, most numerical models are in agreement
amplifying the upper level trough into a closed low across eastern
CO, then tracking this upper low east-southeast into southern KS and
northern OK by 00Z FRI. Ahead of the upper trough, the mid and
upper flow will become more meridional through the day. There may
be a break after the morning elevated storms shift northeast of
the CWA. During the afternoon hours, sfc based storms may develop
along the the dryline which will punch northeast into south
central KS and then along the surface cold front which will move
east into the western counties of the CWA. The best vertical
windshear is forecasted to be across the eastern counties during
the late morning and early afternoon hours even though MLCAPE will
only be less than 200 J/KG. The best instability axis with
MLCAPES around 1200 J/KG will develop ahead of the surface front
across the western counties of the CWA and extend southeast into
south central and southeast KS. However, the 0-6KM effective shear
will decrease to less than 30 KTS as mid level winds back to the
southeast and east on the north side of the H5 low. Therefore, the
potential exist for a line of thunderstorms to develop along the
front and a potential line of storms developing ahead of the
dryline across south central KS. There may be enough instability
and vertical windshear for some updrafts to rotate within the
line, so quarter to half dollar size hail will be possible within
the embedded updrafts. 700MB flow will be from the south at 50KTS
to the south of I-70, so any line that develops may tap into these
stronger winds at 700mb and produce 50 to 60 MPH wind gusts.
North of I-70 the vertical wind shear looks much weaker, thus the
best chance for strong to severe thunderstorms Friday afternoon
will be southwest of a Concordia to Ottawa line. After 3Z the line
of stronger storms will be existing our southeast counties into
MO.

Highs will only warm into the upper 60s to mid 70s, due to the cloud
cover and periods of rain and thunderstorms.

As the upper low moves east southeast KS and northeast OK, wrap
around moisture and mid level frontogenesis will provide rain
chances through the night. There may be some marginal instability in
the wrap around rain for some elevated storms.

Saturday through Sunday, looks as if the CWA will be between upper
level troughs. Highs Saturday will in the mid 50 across north
central KS with lower 60s across east central KS. Clouds will
increase during the day Sunday as the next upper trough lifts east-
northeast from the four corners into the central high plains of
eastern CO. Weak east-southeast surface winds along with increasing
cloud cover will only allow highs to warm into the 60s.

Sunday night through Monday, the upper trough over eastern CO will
move east-southeast across southern KS. At this time the best
moisture and instability will remain south across OK Sunday night.
Any thunderstorms that develop through the night will be elevated
and should not be severe. The upper low will move east into MO and
northern AR through the day. There may be scattered rainshowers on
the back side of the upper trough but these should move out of the
CWA during the afternoon hours. Skies will be mostly cloudy and
highs will only reach the lower to mid 60s.

Monday night and Tuesday and upper ridge will move east across the
plains ahead of the next H5 trough that will move into the desert
southwest. Highs on will warm slightly into the mid to upper 60s.

Tuesday night and Thursday, the next in a series of upper level
shortwave trough will east into the central and southern high plains
and amplify into a closed upper low. Moisture return ahead of the H5
low will cause showers and perhaps some isolated thunderstorms to
develop Tuesday night into Wednesday. This upper level trough
will become a closed upper low that may get cutoff from the polar
jet and may linger across the area through the end of the week
providing continued rain chances. Highs will remain in the upper
50s to mid 60s.


&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1217 PM CDT Wed Mar 22 2017

VFR conditions are expected to continue through the afternoon
into the evening hours. An low VFR to MVFR cloud deck is pushing
northward from southern KS. This is expected to impact the
terminals this evening. Light drizzle is expected to develop as
well. Cigs are also expected to drop to MVFR at the Topeka
terminals and possibly IFR/LIFR at MHK overnight into Thursday
morning. Cigs are expected to begin to improve near the end of the
period. Southeasterly winds are expected to increase late this
evening with sustained at 10-15 knots and gusts upwards of 25
knots.


&&

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

$$

SHORT TERM...Baerg
LONG TERM...Gargan
AVIATION...Baerg


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