Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41
000
FXUS63 KTOP 031125
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
525 AM CST Sat Dec 3 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 200 AM CST Sat Dec 3 2016

There are several shortwaves of concern that will have an impact
on the weather through tonight. One is located over northern
Mexico and is forcing moisture to spread northward over the
plains. Another shortwave is located over the northern high
plains, which will progress eastward through out the day. With the
moisture in place as the northern wave approaches isentropic lift
will continue to increase. There is already an area of rain and
snow over southern KS, which will move northward this morning.

As the lift increases over north central KS there will still be
dry air in the lower levels so it might take some time to saturate
before precip can reach the ground. Temperatures in that area are
below freezing and soundings indicate an unsaturated warm nose
just above the surface. So could not rule out light freezing rain
for a brief period. Once the column saturates to the surface the
precip will most likely be snow, which should begin around
sunrise. This band of snow is forecasted to remain over north
central KS through at least the morning. Surface temperatures may
gradually warm towards mid day causing a change over to rain or a
mix. Most of the models agree that around 0.10 to 0.25 inches of
liquid will fall during this period, so these locations could see
an inch or so of snow. Warm soil temperatures will also limit snow
accumulations. The lift is expected to continue in the afternoon
although several models indicate a loss of ice in the cloud with
deep saturation still in the lower levels. Depending on the
strength of the lift this could result in rain and or drizzle.
Temperatures should be just above freezing by this point
otherwise there could be some light icing.

The rest of the forecast area should remain dry through this
afternoon and evening. Clouds will hang around most of the day,
but southeasterly flow will allow highs to reach the 40s and 50s.
Another shortwave will approach the area from the west and
interact with the moisture still in place. Widespread rain should
develop across the entire area with temperatures ranging from the
lower 30s to lower 40s. A majority of the rain looks to fall from
late evening through sunrise. On the western edge of the precip
band temperatures are forecasted to be near freezing so could not
rule out rain changing to snow or a mix again mainly across north
central KS. Although the warm air near the surface should deepen
during the day, which would cause the snow to melt and limit
accumulations.

.LONG TERM...(Sunday through Friday)
Issued at 200 AM CST Sat Dec 3 2016

Area remains between systems Sunday and Monday, as the Saturday
system moves into the Northeast and next pair of systems moves
into Texas and the northern Rockies respectively. Highs in the
40s Sunday rise a few degrees to near 50 for Monday, with
overnight lows in the 20s.

Cold airmass drives southward into eastern Kansas on Tuesday, with
temperatures likely falling through the day. Have some low end
chances for precip with the front passage, but very little qpf
associated with it. Most chances would be for light snow, with
rain in the far east. Highs in the 30s Tuesday fall to lows in
the teens to 20s Tuesday night.

Still some timing and precip differences for the Wednesday system.
EC still comes in a bit slower and with more QPF than the GFS, and
therefore continues to place snow accumulations across the area,
with better chances in the evening. GFS is quicker and weaker,
with precip clear of the area by the evening hours, and less QPF
and therefore less snow accumulation. Given that the system is a
part of a large scale upper trof and not a singular more dynamic
system, would anticipate some variations in the forecast to
continue. System is quite cold, and either case could have some
higher snow to liquid ratios, so wouldn`t take much to see some
accumulation if the track of the trof remains similar in days to
come.

Highs Wed and Thurs are forecast in the 20s, with overnight
lows in the single digits to teens. Enough wind remains Thursday
night to possibly bring some below zero wind chills to northern
and central Kansas. Surface winds swing back around from the south
as the longwave trof moves eastward into Friday, and should bring
high temperatures back up toward freezing.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 516 AM CST Sat Dec 3 2016

VFR conditions are expected through most of the day. This morning showers
will be possible at MHK although the rain should hold off until late
afternoon and evening. This rain will then move towards TOP/FOE in
the evening. Once the rain arrives at the taf sites conditions will
begin to decline. MVFR conditions are expected then possibly becoming
IFR between 06Z and 12Z.

&&

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

$$

SHORT TERM...Sanders
LONG TERM...67
AVIATION...Sanders



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.