Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 121102
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
502 AM CST FRI FEB 12 2016

...AVIATION UPDATE...

.SHORT TERM...(Today and Tonight)
Issued at 248 AM CST FRI FEB 12 2016

Northwest flow continues over the central and northern plains per
the 08Z water vapor imagery and profiler data. One shortwave was
passing over the mid MS river valley as another rotated towards the
Great Lakes around a closed low over the Hudson Bay. An upper ridge
axis stretched from the desert southwest into the northern Rockies.
At the surface, area observations showed a cold front pushing south
through the northern plains and into the forecast area.

Northwest flow is expected to prevail through today and tonight with
no significant synoptic scale forcing to speak of in the model
solutions. This should allow for a modified arctic airmass to build
through the central plains today with cold dry air advection through
the day. The pattern would favor little or no chances for precip
through tonight. However all of the models are pointing to some mid
level frontogenesis on the west side of the surface ridge along with
reasonable saturation potentially nosing into north central KS late
tonight. Forecast soundings and omega progs suggest any vertical
motion from the frontogenesis is probably going to be weak and
shallow. So since none of the models are developing any QPF, think
chances for measurable precip remains very low. Later shifts can
watch trends to see if a mention of flurries is needed after
midnight tonight. Highs today are expected to be cooler due to the
persistent cold air advection. The forecast expects the stratus to
eventually scatter out by mid afternoon for most areas, but if the
cloud cover hangs in afternoon highs may be a degree or two colder.
For now have highs from around 30 near the NEB state line to the
upper 30s in the southern counties based on the boundary layer
mixing to around 900 MB. Lows tonight should range from around 5
above over northeast KS to the mid teens in central KS as the center
of high pressure passes to the northeast of the forecast area across
IA.

.LONG TERM...(Saturday through Thursday)
Issued at 248 AM CST FRI FEB 12 2016

On Saturday arctic high pressure will move across the central US
bringing cooler temperatures to the area. Highs on Saturday will
range from lower 20s to lower 30s. Attention then turns to a
shortwave trough that will track over the northern plains and upper
Midwest. This will send a front through the forecast area Sunday
morning. Just ahead of this front weak isentropic lift will increase
along with saturation. The majority of the models show that there
will be limited ice in the cloud as the trough axis passes overhead.
These two factors support more of a drizzle event across eastern KS.
Although the other important factor the models are consistent on is
the dry air at the surface, which seems deep enough to prevent
drizzle from reaching the ground. The only exception would be far
southeast portion of the forecast area where the moisture connection
is slightly better. Temperatures on Sunday morning are forecasted to
be below freezing, which supports the possibility of freezing
drizzle. Road temperatures should also be below freezing given the
arctic air mass that passes through on Saturday. For now there is
less concern for snow or sleet unless ice is actually present in the
cloud. Continued with lowering chances for precipitation on Sunday,
which agrees with model guidance. Another shortwave trough is
expected to move over the central plains on Monday, but appears to
stay west of the forecast area. Also one on Tuesday that may stay
north of the area. The ECMWF is advertising this wave clips
northeast KS with light precipitation. A quiet warming trend should
begin into late next week as a strong upper ridge builds across the
central US.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 502 AM CST FRI FEB 12 2016

Stratus has eventually worked its way into the terminals. Am a
Little unsure how long stratus will remain in place as the stratus
has struggled to move as far south and west as models forecast.
However satellite shows a pretty good fetch of stratus upstream.
With this in mind, have held onto the low clouds longer into the
day. Think the stratus will eventually scatter out and VFR
conditions should prevail once it does as low level dry air
advection persists into tonight.

&&

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

$$

SHORT TERM...Wolters
LONG TERM...Sanders
AVIATION...Wolters


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