Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 221138
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
638 AM CDT Mon May 22 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 329 AM CDT Mon May 22 2017

The short term period will consist of scattered shower and
thunderstorm chances. As of 08z, a closed upper low continues over
portions of the Great Lakes. A southwest to northeast oriented upper
trough was located from the northern plains into the central high
plains. Radar observations reveal scattered showers along this
trough across portions of northwest KS and southwest NE. Expect
widely scattered showers and isolated thunderstorms to overspread
the area by mid morning as a shortwave traverses the CWA. Weak
isentropic lift within the 300-305K layer may enhance lift across
the area. Instability looks marginal through the morning hours. Mid
level lapse rates range from 5 to 6 C/KG, resulting in MUcape of
only a couple hundred at most. The main trough will traverse the
area late this evening. Again, instability remains minor, with
MUcape approaching 500 J/KG. Therefore, severe weather is not
anticipated. As far as QPF goes, much of area will see less than
0.25", although thunderstorm induced rainfall rates could result in
isolated amounts upwards of a half inch. Any lingering shower should
exit the area near 12z. Increasing cloud cover this morning will
limit high temperatures to the 60s today. Behind the weak surface
front, low temperatures Tuesday morning will range from the upper
40s to low 50s.

.LONG TERM...(Tuesday through Sunday)
Issued at 329 AM CDT Mon May 22 2017

Tuesday, The amplified upper level trough axis will be moving east-
southeast across eastern KS during the day on Tuesday. If we see
some insolation during the afternoon hours then the atmosphere may
be slightly unstable and there may be enough residual moisture
for showers and isolated thunderstorm under the colder upper
level trough axis. Forecast soundings show dry adiabatic lapse
rates from the surface up to 800mb, thus the stronger 850mb winds
of 30 KTS may mix down to the surface which could create some
winds gusts up to 30 MPH from the northwest during the afternoon
hours. The showers and isolated thunderstorms will dissipate after
00Z WED. Low-level CAA will only allow highs to reach the mid
60s.

Wednesday through Thursday, the upper trough across the eastern
plains will shift east across the eastern US. An upper ridge
across the western US will move east across the plains on
Thursday. Wednesday will continue to be cool as a surface ridge of
high pressure shifts southeast across eastern KS. Highs on
Wednesday will reach the mid to upper 60s. Lows will be in the
mid to upper 40s. Highs on Thursday will be warmer with mid to
upper 70s as winds become southerly as a lee surface trough
deepens across the high plains.

Thursday night through Monday, A broad upper level trough will move
into the western US and slowly shift east across the plains on
Saturday. The upper trough will shift east of the area Sunday and
Monday. A surface front will move southward across the CWA on
Friday night and may become stationary along the OK and KS border.
The best chance for showers and thunderstorms will occur late
Thursday night from a complex of storms that may develop across
western KS Thursday evening, and shift east across the state
during the night. There may be another good chance for showers
and thunderstorms on Saturday as the main upper trough axis shift
east across the central and southern plains. It looks like the
best chances for severe thunderstorms will remain west of the CWA
Thursday night and Friday afternoon, then south of the CWA on
Saturday. Highs will be in the upper 70s to lower 80s Friday and
Saturday. Slightly cooler and drier air will advect southeast
across eastern KS Sunday into Monday. Highs Sunday and Monday will
be in the mid to upper 70s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 629 AM CDT Mon May 22 2017

VFR conditions are expected throughout the period. Scattered
showers and isolated thunderstorms will increase in coverage by
late morning into the afternoon. The initial round of
precipitation is expected to push south of the terminals by early
evening. A secondary area of showers and thunderstorms are
possible after sunset into the overnight hours. Guidance is
suggesting the possibility for low cigs near the end of the
period. Will reevaluate in subsequent outlooks.

&&

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

$$

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



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