Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 112040

Area Forecast Discussion
National Weather Service Topeka KS
340 PM CDT Sun Mar 11 2018

.SHORT TERM...(This evening through Monday)
Issued at 333 PM CDT Sun Mar 11 2018

The biggest challenge for the rest of the day and tonight will be
timing the clearing of the stratus shield currently in place
across the region.

Early afternoon water vapor imagery showed a departing upper
level PV anomaly over central Missouri while at the surface a
meridional surface ridge axis stretched along the High Plains and
the Front Range. Stiff northerly flow over the Central Plains
should gradually diminish today and tonight as the pressure
gradient relaxes ahead of the approaching ridge. A broad expanse
of stratus encompassed the eastern half of NE/KS, MO, and much of
IA. The western edge of the stratus has been steadily eroding over
the course of the day. RAP/HRRR forecast soundings in combination
with visible satellite indicate that the overall shield is quite
thin, but has failed to mix out owing to the continued CAA in the

We are approaching the time of year where solar insolation is
high enough to start breaking up such thin stratus decks, which
makes timing the clearing of these clouds rather tricky. Given the
lack of breaks developing in the cloud shield, have leaned
towards a more conservative solution--not clearing the clouds out
east of Manhattan until after sunset. Clouds should clear out by
the time low temperatures are reached tonight, but clouds may keep
readings 5-8 degrees warmer in the far east compared to west of

Monday will see the surface ridge axis positioned directly over
the CWA, with temperatures rebounding somewhat into the low 50s
under mostly clear skies. Mid to high clouds will increase late in
the day ahead of a weak H500 vort max.

.LONG TERM...(Monday night through Sunday)
Issued at 333 PM CDT Sun Mar 11 2018

Little sensible weather is forecast for much of the week with
warming temperatures for the middle to latter part of the week.

A large omega block sets up over the western CONUS by late in the
day on Monday and lingers for much of the week. Eastern Kansas
will at first be on the cool side of the attendant lower
tropospheric ridge with H850 temps hovering around -2 to -4 C
during the daytime on Tuesday. However, as the block gradually
migrates east, return flow builds eastward into the CWA by midday
Wednesday, pushing temperatures back into the 50s and 60s. The
increase in dry SW flow may present some fire weather concerns for
Wednesday that bear watching. Continued WAA on Thursday pushes
H850 temps to +10 C and surface temps into the 70s. A weak H500
perturbation pushing through the Great Basin Thursday evening will
lead to lee cyclogenesis along the Front Range and increasing
baroclinicity ahead of the low across northern KS. A few elevated
showers and storms are possible early Friday morning in
conjunction with the passage of the H850 wave.

The evolution of the low once it pulls off the Front Range early
Friday is somewhat uncertain with varying solutions between the
GEM/GFS/EC. The EC is the faster of the three solutions and brings
much cooler air in on its backside compared to the GEM/GFS. This
will be something to watch for high temperatures on Friday given
the current forecast of low 70s for NE Kansas (while the EC highs
range from the low 40s to upper 50s). Looking to next weekend,
the upper level ridge breaks down--with a lobe of energy digging
southward and then ejecting eastward into the central U.S. with a
120 kt jet streak. This will lead to the development of a
seasonably strong extratropical cyclone that could bring with it
showers and thunderstorms to NE Kansas. The timing and details of
this system will be hashed out in the coming days.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1230 PM CDT Sun Mar 11 2018

MVFR stratus lingers across northeast Kansas for much of the day,
gradually clearing from west to east this afternoon and tonight.
Ceilings at TOP/FOE will likely not break until after 06Z tonight.
NNW winds will persist through the period, decreasing from 10-20
kts today to 5-10 kts tonight.




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