Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 42 43 44 45 46 47 48 49 50

FXUS63 KTOP 270508

National Weather Service Topeka KS
1208 AM CDT Thu Oct 27 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Thursday)
Issued at 255 PM CDT Wed Oct 26 2016

The mid-level trough was progressing east of the area with a mid-
level ridge stretching across the western U.S. As the mid- level
ridge and surface high pressure builds eastward into the central
U.S., cloud cover will continue to scatter out across eastern
Kansas. With clear skies and light winds shifting from north to
southeast overnight, expect decent radiational cooling to support
low temperatures plunging into the mid/upper 40s. Models do not
show much change in the dewpoint temperatures overnight with
moisture pooling at the surface as a result of the rainfall from
earlier this morning. As a result, the combination of low- level
moisture, light winds, and clear skies will likely result in some
patchy fog development overnight into Thursday morning across much
of the forecast area. This fog should dissipate by mid morning as
conditions dry out in the low-levels with increased mixing. With
southerly winds in place through the day, expect more mild
conditions with afternoon high temperatures rising into the
mid/upper 70s from east to west.

.LONG TERM...(Thursday night through Wednesday)
Issued at 255 PM CDT Wed Oct 26 2016

The forecast for Friday through Tuesday looks to remain dry as the
overall pattern favors ridging over the southern plains with
periodic shortwaves passing across the northern plains. Will need
to watch trends for Monday as the GFS and ECMWF bring a well
defined shortwave across NEB and SD. However moisture appears to
be limited across the state and models keep the strongest PVA and
Q vector convergence north of the forecast area. The forecast
keeps a mention of precip chances for Tuesday night and Wednesday.
There is some uncertainty in that the GFS shows a warm air
advection pattern with moisture advecting north through the
period. On the other hand, the ECMWF wants to bring a weak
boundary into the area with a weaker warm air advection signal.
The GFS shows the moisture advection to be on the shallow side
with forecast soundings keeping the moisture capped and the prev
ECMWF did not show the boundary over the forecast area. So
confidence in precip chances is low for Tuesday night and
Wednesday and have just a slight chance for showers and
thunderstorms. GFS forecast soundings would support enough
elevated instability for thunderstorms.

Temps should remain mild through Wednesday as models keep the cold
air bottled up to the north. It looks like the Topeka area will go
through the month of October without a freeze. The last time that
was the case was in the fall of 1998 when Topeka`s first freeze
happened on Nov 11th.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1200 AM CDT Thu Oct 27 2016

Visibilities are beginning to decrease at the start of the TAF
period, and should continue to decrease over the next several
hours with all TAF sites likely to have vis less than 2 miles, and
possibly 1/2SM or less. Then expect an improvement in vis after
14Z with a small chance for a few hours of BKN IFR/MVFR cigs
after the fog dissipates but for now have focused on the vis
restrictions as it may also dissipate to SKC.


Dense Fog Advisory from 3 AM to 9 AM CDT this morning for



SHORT TERM...Hennecke
LONG TERM...Wolters
AVIATION...Barjenbruch is the U.S. government's official web portal to all federal, state and local government web resources and services.