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000
FXUS63 KTOP 301152 AAA
AFDTOP

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TOPEKA KS
552 AM CST Fri Jan 30 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 350 AM CST FRI JAN 30 2015

Recent IR satellite and water vapor imagery showing high level
moisture/clouds spreading eastward across KS from the upper
trough in the southwest CONUS. Although initially thin...the clouds
will steadily but slowly thicken west to east across the cwa today
into this evening before becoming totally overcast tonight.
However...should still see some insolation combining with veering
low level flow to the south by afternoon and warm advection through
850 mb to push highs into the middle to upper 40s.

Clouds...some mixing and continued warm air advection tonight would
suggest nearly steady or even slightly rising temperatures in some
areas...however expect some evaporative cooling to occur so only
tweaked lows up slightly into the lower 30s. Forecast soundings
still showing freeze levels a little high for much snow to make it
to the ground before melting...but will keep it across the west and
north and go only rain chances south (east central) for now. Either
way...higher pops and no snow accumulation still in order across the
cwa overnight with rainfall amounts generally under a tenth of an
inch...especially east.

.LONG TERM...(Saturday through Thursday)
Issued at 350 AM CST FRI JAN 30 2015

Saturday through Saturday Night, An upper level trough across the
southwestern US will slowly move east into far west TX, while an
upper level trough embedded within the northern stream of the mid
and upper level jet digs southeast across the northern and central
high plains. Slightly warmer boundary layer air parcels will
advect northward across the CWA through he morning hours of
Saturday. Surface temperatures will warm from the lower to mid 30s
at 12Z Saturday into the mid and upper 30s by noon. Forecast
soundings show the depth of the warmer boundary layer airmass to
be warm enough to change the mix of rain and snow across much of
the CWA over to periods of light rain through the mid and late
morning hours of Saturday. Most of the CWA will see light rain
through the afternoon hours into the mid and late evening hours.
After midnight, the northern stream H5 trough will dig southeast
across the central plains bringing cooler air at both the surface
and 850mb. The light rain will begin to mix with snow and will
change over to light snow during the early morning hours of
Sunday. Most of the stronger ascent and frontogenetical forcing
will shift northeast of the CWA, thus any snow accumulations will
be light, with a dusting or less. The best chance of seeing
measurable snowfall will be across the northern counties of the
CWA where an inch of snow may fall late Saturday evening into
Sunday Morning. Some areas along the NE border may get over an
inch of snowfall, perhaps near 2 inches in northern Brown County.

Most areas should see about a half inch of rainfall with the eastern
counties receiving between one half and three quarters of an inch of
QPF. Once again the cold air in the low-levels will arrive too late
to see much in the way of snowfall. Overnight lows will drop into
the 20s across north central and northeast KS with lower to mid 30s
across east central KS.

Sunday through Sunday Night, the central plains H5 trough will
amplify On Sunday as it digs east-southeast across the mid MS
river valley. Portions of northern IL, northern IN and Northern OH
will see 6 to 8 inches of snowfall on Sunday. There may be some
left over flurries for very light snow during the morning hours of
Sunday across the eastern counties of the CWA. Strong low-level
CAA will only allow Highs to reach the mid 20s along the NE border
to the mid 30s across the southeast counties. North winds of 15 to
25 MPH with higher gusts will make it feel much colder on Sunday.
Any leftover moisture on area roadways may freeze causing slick
spots on area roadways Sunday morning.

Lows Sunday night will drop into the teens and perhaps some single
digits along the NE border.

Monday through Thursday, A longer wave length upper trough will
remain across the eastern US. Monday will continue to be cold as a
surface ridge of high pressure builds southeast across eastern KS.
Highs will only reach the lower to mid 30s. We`ll see a brief warm
up on Tuesday ahead of the next surge of cold air by mid week. Highs
on Tuesday will reach the mid to upper 40s. Wednesday another
strong cold front will move southward across the CWA. Highs on
Wednesday may occur during the morning hours, with temperatures
falling into the 20s by afternoon.  Highs on Thursday will only
reach the mid 20s to lower 30s, though the ECMWF if much colder and
if it were to verify, highs may only reach the teens. An H5 trough
embedded in the northwesterly flow aloft will track southeast across
CO into OK and bring a chance of accumulating snowfall to western
and southern KS on Thursday.

&&

.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 544 AM CST FRI JAN 30 2015

Expect only sct-bkn mid and high clouds through 03z as light east
winds veer to the south and southeast by 18z at speeds under 8 kts.
Increasing warm air advection with frontogenetical forcing aft
06z will result in cigs lowering to 3500 to 4000 feet and 5-6
miles in light rain through the end of the terminal forecast.
South winds will continue at speeds under 8 kts.


&&

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

$$

SHORT TERM...63
LONG TERM...Gargan
AVIATION...63