Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 292346
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
546 PM CST Tue Nov 29 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday)
Issued at 303 PM CST Tue Nov 29 2016

Main closed low continues to rotate over Minnesota while a secondary
upper trough is centered over New Mexico this afternoon. This
secondary southern stream shortwave trough will allow the closed low
to gradually push eastward this evening into Wednesday. Meanwhile
towards the sfc, wraparound precipitation has produced areas of
light snow over central NE into northwest KS, while the associated
cloud cover has made its way into north central Kansas. Expect this
cloud cover to spread southeast overnight as winds shift to the west
northwest at around 10 mph. Despite the insulation, cool advection
near the sfc will drop lows Wednesday morning into the upper 20s and
lower 30s.

A much cooler afternoon is in store with strong cold advection with
sustained wind speeds at the sfc from 10 to 20 mph. Wind gusts are
up to 30 mph, creating wind chill readings from the lower to middle
30s. Areas of low and mid level moisture from the upper low will
keep the mostly cloudy skies across the area as highs struggle to
reach the lower and middle 40s.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 303 PM CST Tue Nov 29 2016

Dry and seasonal conditions are expected for the latter half of the
week as the mid-level trough lifts northeast across the Great Lakes
region and further into Canada. Somewhat zonal mid-level flow will
set up across the central U.S. behind this trough with surface high
pressure settling in.  Northwesterly winds will help to keep cooler
yet seasonal with highs in the 40s and lows in the 20s. By Thursday,
models show a weak shortwave trough developing across the Pacific
Northwest that will deepen into the southwestern U.S. through late
week.  12z model runs are starting to show better agreement with the
evolution of this system, with the ECMWF now developing a closed mid-
level low over the Baja peninsula (as the GFS/Canadian have been
doing).  With this closed low pivoting across the southwestern U.S.,
most of the moisture will remain further south of the CWA. However,
models are showing the potential for some energy from the closed low
to lift northeastward and get wrapped into the trough that remains
across the Northern Plains.  As a result, some scattered
precipitation may develop across portions of northeast and east
central KS Saturday night into Sunday morning. However, any
available moisture and lift looks to be limited, so precipitation
would be light. Models are also trending a couple of degrees warmer
over the weekend, which would support precipitation remaining
predominantly in the form of rain. However, if temperatures end up
dropping to near freezing and precipitation has not exited to the
east yet by Sunday morning, cannot rule out some snow mixing in with
the rain. Do not expect any cooler air to enter the region behind
this passing wave, so high temperatures Sunday into Monday will
still be in the 40s to around 50 degrees with lows in the 30s.

Models are showing a stronger system developing late weekend into
early next week as a mid-level trough moves into the Pacific
Northwest. Both the GFS and ECMWF show this trough deepening into
the southwestern U.S. and just west of the Rockies through the first
half of the week.  This advancing trough will help to push an area
of low pressure and associated cold front eastward toward the CWA.
There are discrepancies in the timing of this front, but there is a
slight chance for some scattered showers to develop Monday into
Monday evening.  There looks to be better chances for precipitation
by mid-week as the deep mid-level trough and closed-low lift into
the central U.S.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 538 PM CST Tue Nov 29 2016

Broken cloud cover will impact TAF sites through much of the TAF
period but expect ceiling heights mainly in the 3500 to 6000 foot
range. Wind gusts increase to the 18-26 kt range by late Tuesday
morning into the afternoon.

&&

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

$$

SHORT TERM...Prieto
LONG TERM...Hennecke
AVIATION...Barjenbruch



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