Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 141738
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1138 AM CST Sat Jan 14 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 549 AM CST Sat Jan 14 2017

Appears main area of shower activity has exited to the east. This
appeared to be on the edge of the deeper moisture aloft along with
some mid-level upglide. Seeing ceilings lowering in east central
Kansas as frontal boundary becomes a bit more shallow with
visibilities coming down as well. Isentropic surfaces and
soundings in this area showing little in the way of vertical motion,
but could see some drizzle from this lower cloud/higher sfc RH area
this morning.

Models are consistent in mid-level drying continuing this morning
with winds around 850mb veering to the WSW early. This should end
any mentionable chance for freezing rain, but could still see
freezing drizzle in the lower cloud along/south of I-70, but more
likely along/south of I-335. Deeper moisture then begins to return
this afternoon and spread northeast this evening as upglide,
though modest, returns. Higher confidence in precip remains in the
southern half late in the night as moisture/lift increase, but at
least scattered activity anticipated for the entire area. Should see
a few degrees of temperature rises through the day and could breach
freezing. Models continue to struggle with dewpoints, but
observations support HRRR values the closest. This keeps most
dewpoints still several degrees below freezing, and thus freezing
rain as the primary weather type through these periods.

.LONG TERM...(Sunday through Friday)
Issued at 549 AM CST Sat Jan 14 2017

Precipitation will continue to ramp up across the area on Sunday as
the upper low begins to pivot into southeast New Mexico and far west
Texas. Moisture will continue to surge northward into the Central
Plains over the low level cold air near the surface. Isentropic lift
as well as upper level diffluence through the day will generate a
swath of freezing rain across the area into the early afternoon
hours. As surface temperatures gradually warm later Sunday afternoon
and evening the freezing rain will transition over to all rain.
Thermal profiles suggest that much of north central and a good part
of northeast Kansas will see surface temperatures remaining near or
below freezing through the evening and overnight hours. As the upper
low pivots northeast into southwest Kansas Sunday night mid and
upper level forcing will increase with widespread precipitation
expected across the the cwa. Main concern continues to be the timing
of the eroding of the low level cold air and any fluctuations in
temperature will affect the amount of freezing rain Sunday afternoon
and Sunday night across northeast and east central Kansas.
Freezing rain amounts for the storm still average around a half inch
with higher amounts in north central Kansas approaching 0.75 inch.
The upper low moves into north central Kansas on Monday with the
deformation zone shifting north into Nebraska and southwest Iowa
with a dry slot moving into south central Kansas. Models shift the
upper low into Iowa and Missouri Monday evening with precipitation
ending by midnight. The rest of the week continues to look dry with
upper level ridging building into the region. Models differ on the
timing and strength of an upper level system in the Plains late
Friday. Confidence is low and will keep the forecast mainly dry or
slight chances of rain. Temperatures will be quite mild for mid
January with highs in the 50s and lows 20s and 30s warming through
the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1127 AM CST Sat Jan 14 2017

TAFs start out VFR with most ceilings in the area around 4000
feet. A large area of freezing rain will move toward TAF sites,
likely arriving in the 04-08Z time frame. When this arrives,
conditions will rapidly decrease to IFR and possibly LIFR with
occasional freezing rain continuing through the remainder of the
TAF period. Freezing rain is very likely to accumulate on all
surfaces at all TAF sites.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Ice Storm Warning from 6 PM this evening to midnight CST Sunday
night for KSZ024.

Ice Storm Warning until midnight CST Sunday night for KSZ026-
035>040-054-055.

Ice Storm Warning from 6 PM this evening to noon CST Monday for
KSZ008>012-020>023-034.

Ice Storm Warning until noon CST Sunday for KSZ056-058-059.

&&

$$

SHORT TERM...65
LONG TERM...53
AVIATION...Barjenbruch


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