Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 230521
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1121 PM CST Thu Jan 22 2015

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Friday)
Issued at 335 PM CST THU JAN 22 2015

An upper level trough across eastern NM will move east across
central TX Tonight and Friday. The stronger ascent and precipitation
will remain well south of the CWA.

Weak isentropic lift at the 280K theta level across the eastern
half of the CWA have kept the low stratus in place through the early
afternoon hours. The isentropic lift is forecasted to weaken
during the late afternoon hours and the stratus should dissipate
after 500 PM across the eastern counties of the CWA.

Tonight skies will become mostly clear. The center of the surface
ridge will move across the CWA Tonight, thus winds will be light.
Overnight lows will drop into the upper teens to lower 20s.

Friday, a surface trough will move east across the state of KS, as
the upper level flow becomes northwesterly. Southwesterly surface
winds ahead of the surface trough will help to warm temperatures
into the upper 40s to lower 50s. Forecast soundings show mixing
heights to be about 900MB during the early afternoon hours. Drier
air aloft may cause dewpoints to drop into the upper teens to lower
20s. Minimum RHs may drop to around 30 percent, but given dry fuels
and southwest winds gusts up to 20 MPH, expect high to very high
fire danger across the CWA Friday afternoon.

.LONG TERM...(Friday Night through Thursday)
Issued at 335 PM CST THU JAN 22 2015

Northwest flow aloft will continue across the county warning area
through the weekend. The low level flow across the area will begin
to back in response to the next upstream shortwave entering the
northern plains. This will result in warm advection across the area
with high temperatures on Saturday rising into the middle to upper
50s. The westerly winds and a gradual increase in clouds thru
Saturday night will also help to keep temperatures from falling
beyond the middle 30s. The better forcing with the approach and
passage of the shortwave trough will occur to the north and east of
the county warning area...so have maintained a dry forecast for now.
The EC and GFS are not in good agreement on the low level thermal
fields during the day with the EC much cooler and GFS warmer. Have
opted with a blend for now which is slightly cooler with highs
ranging from the mid 50s far northeast to low 60s far southwest
counties.

Models are in better agreement on a slight cooldown for Monday with
highs ranging from the upper 40s far northeast corner to the upper
50s southwest. Slightly warmer air will then edge back eastward for
Tuesday with highs in the middle 50s to lower 60s. Western upper
ridge axis shifts eastward through the middle of next week and
slowly deamplifies as it does. Will keep highs in the 50s for
Wednesday and Thursday with dry conditions...but if the ridge
remains stronger...highs could be warmer in the 60s.

&&

.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1118 PM CST THU JAN 22 2015

Only concern with this taf period will be the potential for fog or
haze to form as the nocturnal inversion becomes stronger than
predicted. For now went with VFR, but there is a chance it could
impact the flight categories during the pre-dawn hours.

&&

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

$$

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





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