Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 182145

345 PM CST Thu Dec 18 2014

.SHORT TERM...(This Evening through Friday)
Issued at 341 PM CST THU DEC 18 2014

The upper trough that brought last night`s snowfall was already
moving eastward across the mid MS river valley. An upper level
trough will move east across the northern plains Tonight. A surface
ridge of high pressure will extend from the upper Midwest, southwest
across eastern KS into the TX PHNDL.

The better chance for freezing drizzle will occur across western KS,
northeast into east central NE. Very weak isentropic lift will
develop at the 275 theta surface, from I-70 north after 8Z, so I
cannot rule out a slight chance for very light and patchy freezing
drizzle. But my confidence is low enough to keep it out of the
forecast. There may be areas of fog developing through the night as
well. The best chances for patchy dense fog will be across the
southern counties of the CWA. Lows Tonight will gradually fall into
the mid to upper 20s. Therefore any wet pavement may re-freeze and
form icy patches Friday morning.

An upper level trough across the four corners region this afternoon
will fill as it moves east into the southern plains Tonight and
Friday. The best combination of moisture and lift will be well south
of the CWA across southern OK into eastern TX where a broad area of
rainfall will develop. Expect a cloudy and dry day on Friday. Highs
Friday will struggle into the mid 30s.

.LONG TERM...(Friday Night through Thursday)
Issued at 341 PM CST THU DEC 18 2014

Weak southerly low level flow will support a continuation of the
stratus into Saturday morning and possibly beyond into Saturday
night as well. Considered adding patchy fog at night into the
grids...although not sure stratus deck will be supportive of low
visibilities. The exception would be breaks/clearing in the overcast
late in the day or at nighttime...or we are able to advect deeper
moisture back into the area at night with the cool temperatures.  If
either of these cases were to occur...dense fog would be
likely...especially with wet ground and melting snowcover to come.
Either way...with the warm advection have increased highs into the
low to mid 40s for Saturday. With the increasing warm air advection
on Sunday ahead of the next clipper system in the northern
plains...will maintain the middle to upper 40s...although cloudcover
(both low and high level) are still a concern.

Will keep highs ahead of the cold front on Monday in the
40s...although if the clipper/front move through the area earlier in
the day...highs may be cooler and temps falling in the afternoon.
Either way...will maintain a chance for rain ahead of the system
Sunday night into Monday...then a rain/snow chance Monday night into
Tuesday across mainly the northeast county warning area as the
system deepens and cooler air filters southward. With the trough
over the eastern CONUS...northwest flow will persist across the area
through mid week with a dry forecast and highs in the upper 30s and
lower 40s. The EC and GFS models are in better agreement in bringing
the next stronger shortwave trough over the western ridge and into
the central plains by Christmas Day. Have therefore introduced a
chance for snow at that time for all areas except the far southeast
corner with highs in the 30s.


.AVIATION...(For the 18Z TAFs through 18Z Friday Afternoon)
Issued at 1135 AM CST THU DEC 18 2014

Expect the low stratus (IFR) and light fog to continue across the
KTOP and KFOE terminals through the forecast period. KMHK had
ceilings of 1500 feet but these ceilings should fall to around 800
feet this evening. Patchy flurries and/or patchy freezing drizzle
may develop across the terminals Tonight through 15Z FRI.




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