Area Forecast Discussion
Issued by NWS Topeka, KS

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706
FXUS63 KTOP 132348
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
548 PM CST SAT FEB 13 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Sunday)
Issued at 259 PM CST SAT FEB 13 2016

A weak upper trough will dig southeast across the central plains
later tonight and will move east-southeast into the upper and mid MS
river valley on Sunday.

Isentropic lift will increase by 6Z along the 285K theta surface and
will cause enough lift to begin to saturate the 900-800mb level but
given 100mb condensation pressure deficits in the region of greatest
isentropic lift across east central KS, I am uncertain if enough
lift will occur for saturation to produce freezing drizzle. Also,
most forecast soundings show a dry layer from the surface to about
900 mb. The stronger isentropic lift will begin to shift east of the
CWA after 9Z SUN. The best chance to see some spotty freezing
drizzle will be along and east of US HWY 75 from 9Z to 12Z. Motorist
should pay close attention to later updates, since even spotty
freezing drizzle could cause some slick spots on roadways across
portions of northeast and east central during the early morning
hours of Sunday. Overnight lows will occur this evening with lower
to mid 20s but temperatures will slowly rise after midnight as
surface winds become more southerly.

Sunday, Any spotty freezing drizzle in the morning across the far
eastern counties will end by 9 AM. Isentropic down glide should
begin to clear skies from west to east across the CWA during the
late morning and early afternoon hours. Westerly surface winds
combined with insolation should help temperatures warm into the
upper 40s to lower 50s.

.LONG TERM...(Sunday Night through Saturday)
Issued at 259 PM CST SAT FEB 13 2016

By Sunday night, a mid-level trough axis will be situated just
west of the Great Lakes region, with the Northern and Central
Plains under northwesterly flow aloft. Models show a weak embedded
shortwave developing within the western edge of this trough,
skimming southeastward into central Kansas after midnight and into
Monday morning. There will be some isentropic lift with this
shortwave, but there`s uncertainty in the amount of available
moisture. While temperatures look to be in the low 30s by Monday
morning, model soundings show a strong warm nose just off the
surface, so expect any precipitation to be in the form of
sprinkles. Models show a stronger embedded shortwave trough
developing across the Northern Plains Monday evening and likely
skimming across far northeast and east central Kansas Monday night
into Tuesday morning. Better moisture and lift will be associated
with this shortwave, but it will be predominantly focused to the
north and east of the area. Low temperatures in far eastern Kansas
should drop into the mid 30s, but model soundings still show a
strong warm nose in place so have kept precipitation in the form
of rain or sprinkles.

Once that shortwave exits the area Tuesday morning, the mid-level
flow will gradually transition with a ridge shifting into the
central U.S. by Wednesday night. This advancing ridge will help to
push an area of surface high pressure into the eastern U.S.,
resulting in steady southerly flow into the region. Temperatures
will be mild for the start of the week, in the 50s, with even warmer
conditions expected with the advancing mid-level ridge. Have
continued to trend on the warm side of guidance with highs reaching
around 60 degrees for Wednesday. Thursday is looking to be the
warmest day as a strong pressure gradient will be in place,
resulting in breezy southerly winds and decent warm air advection
pushing temperatures into the upper 60s to low 70s. Slightly cooler
conditions are expected by next weekend as a low-pressure system
tracks northeast of the area, but temperatures are still looking to
be mild in the 50s and 60s on Saturday&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1114 AM CST SAT FEB 13 2016

The persisting low end VFR cloud deck is expected to remain this
afternoon and early evening.  Ceilings may briefly lift above 10kft
tonight before lowering again by early morning.  Some guidance
suggests these early morning ceilings will be right at or below 3kft
and will move into terminals after 10Z at TOP/FOE along with chances
for -FZDZ. Right now, confidence is still not high enough to mention
in this TAF issuance.  SE winds will shift from the west-southwest
early tomorrow morning.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 546 PM CST SAT FEB 13 2016

Added a short term MVFR group before sunrise as most guidance
supports a deck around 2500-3000ft agl. Low clouds push east
quickly as winds become southwest then northwesterly as next
system approaches.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Gargan
LONG TERM...Hennecke
AVIATION...67



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