Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 130435
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1135 PM CDT Fri Sep 12 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Saturday)
Issued at 304 PM CDT FRI SEP 12 2014

Broad upper trough axis continues to rotate east over the Great
Lakes this afternoon. Very weak low level lift persists for the next
few hours with patchy drizzle across locations south of Interstate
70. Low level stratus deck scatters out from north to south this
evening as an expansive area of high pressure spreads southeast over
the central plains. Decent radiational cooling at the surface
combined with light winds may develop patchy fog towards sunrise,
especially in low lying areas where visibility may fall below 2
miles. Next concern is the potential for patchy frost as the center
of the ridge axis settles over the northeast corner of the CWA.
Latest NAM and GEM are indicating a slightly stronger sfc inversion
compared to ECMWF and SREF guidance, dropping dewpoint and sfc
temperatures in the middle 30s over far northern Kansas. Dependent
on placement of ridge axis, these temps may fall a few degrees lower.
Opted not to issue a frost advisory for these areas as it appears
difficult to achieve widespread frost with ground temps lingering in the
mid to upper 60s. Further south, lows tonight range in the middle to
upper 30s.

A dry and pleasant afternoon for Saturday as surface high slides
eastward. Weak winds veer to the southeast during the day around 10
mph. After a cold start to the day, highs only manage into the low 60s.

.LONG TERM...(Saturday Night through Friday)
Issued at 304 PM CDT FRI SEP 12 2014

Sunday shaping up to bring a nice finish to the weekend with
mostly clear skies and light southerly winds making a return.
Morning lows in the 40s should rise to low/middle 70s by mid
afternoon.

Next shortwave moves through NW flow aloft for Monday. Leading
warm air advection may generate some overnight showers possibly a
rumble of thunder, then may bring enough heating to mainly eastern
and southern portions of the area on Monday for another round of
showers and thunderstorms as the main surface front passes through
the day. GFS is a little slower and could lean to little better
coverage if given a few more hours to destabilize before the front
comes in. NAM brings late afternoon surface based cape in southern
counties around 1000 J/kg but overall shear is weak. Have lows in
the 50s rising to highs in the 70s as front comes through, with
chance of precipitation most areas spreading NW to SE and
diminishing through late Monday night. Similar temperatures follow
behind for Tuesday as cooler high pressure settles in but skies
clear and bring better insolation for the day, along with a shift
back to southerly winds.

Kept slight chance PoP for Wednesday but confidence is quite low
given precipitation will depend on where best WAA sets up, with EC
farther east over eastern KS while GFS keeps activity west. Should
get back toward middle and upper 70s by Wednesday afternoon.
Thursday and Friday bring a continued warming trend before next
more amplified shortwave trof approaches toward the weekend. Again
some strength and timing differences but kept dry forecast at this
time.

&&

.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1101 PM CDT FRI SEP 12 2014

Skies have cleared out at TAF sites and would expect mostly clear
skies to prevail as surface high pressure moves over eastern KS
tonight. With clear skies, light winds and residual moisture,
patchy areas of fog may form in low-lying areas and primarily
affect TOP and MHK between 9Z and 14Z. Visibilities could get down
in the low IFR range at times at those two sites.

&&

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

$$

SHORT TERM...Bowen
LONG TERM...67
AVIATION...GDP





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