Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 111142 AAA
AFDTOP

Area Forecast Discussion...UPDATED
National Weather Service Topeka KS
542 AM CST Thu Jan 11 2018

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 300 AM CST Thu Jan 11 2018

Intense upper system evident on water vapor is currently moving
into southern KS with strong dynamic lift combining with
isentropic forcing across the CWA to produce a widespread shield
of rain at the moment. Meanwhile, strong 850-600mb frontogenetic
forcing has produced a band of moderate to heavy snow which is
approaching the CWA from the northwest. Expect precip to increase
through 15z as the two forcing mechanisms work to produce an axis
of moderate to heavy snow across mainly areas west of a Hiawatha
to Council Grove line this morning. This is where the forcing will
be strongest and moisture the deepest on the northwest periphery
of the upper system. Soundings suggest some instability so
response to forcing may be enhanced so snowfall may be heavy at
times this morning. Just as importantly...pressure gradient
combined with very strong 40kt winds atop the inversion will
produce strong gusty winds of 30 to 40 mph for a time this
morning. The combination of the winds and snow could lead to near
blizzard conditions in spots for a few hours this morning and have
opted to upgrade to a winter storm warning where the combo of wind
and snow appears to be greatest. Duration of snow will not be more
than 6 hours so short intense duration could lead to 2-5 inch
amounts. Further southeast the rain will transition to a brief
period of freezing rain then sleet to snow. Frontogenetical
forcing is not as strong and lift in dendritic growth zone not as
robust so feel that light snow and advisory appears more
appropriate for now. Any ice accumulations should also remain
light and if measurable a few tenths of an inch.

.LONG TERM...(Friday through Wednesday)
Issued at 300 AM CST Thu Jan 11 2018

Extended period features northwest flow becoming more amplified by
early next week. There will be at least a couple of chances for
light snow across the area one over the weekend and another with
an Arctic front early next week. Temperatures will remain below
average and could drop near or below zero again by early next
week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 533 AM CST Thu Jan 11 2018

Expect MVFR along with periods of IFR VIS and CIGS through 18Z due
to precip in the form of freezing rain and snow. The mixture will
transition to snow which could reduce visibility mainly at MHK
this morning. The precip should end by 18z with MVFR conds
expected thereafter along with gusty winds through 00z.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until noon CST today for KSZ008>012-020>024-
034>038.

Winter Weather Advisory until noon CST today for KSZ026-039-054-
055.

Winter Weather Advisory until noon CST today for KSZ040-056-058-
059.

&&

$$

SHORT TERM...Omitt
LONG TERM...Omitt
AVIATION...Omitt



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