Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 251720
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1120 AM CST Sun Jan 25 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 253 AM CST SUN JAN 25 2015

Mid-level shortwave is currently digging southeast over northeast
KS and eventually the mid MS valley later today. Isolated to
scattered showers have developed in response to the wave, and are
moving eastward through the forecast area. Several pieces of
energy associated with the wave are going to move over the area
through late morning especially far eastern KS. Have kept a slight
chance for these showers through noon when the wave moves further
east and subsidence as well as dry air takes over. With a fairly
mixed boundary layer and cloud cover the temperatures will remain
steady until cold air advection increases later this morning. Most
areas will stay in the 40s while far northeast KS could reach the
upper 30s based on upstream temperatures in central NE. Given the
strength of this system a decent pressure gradient has developed
over the plains. The northwesterly low level jet currently over
central NE will drop south into central KS and portions of eastern
KS during the morning hours. Mixing levels across KS will not vary
much from areas that have already received gusts over 45 mph. As
of now have sustained winds around 25 to 35 mph with gusts around
40 to 45 mph. These wind gusts could move into northern KS as
early as sunrise, but likely increase and become more widespread
late morning once daytime mixing begins. The pressure gradient is
forecast to weaken during the afternoon hours therefore expect the
surface gusts to do the same. Clouds will hang around most of the
day with high temperatures ranging from lower 40s in northeast KS
to upper 40s in central KS. A surface ridge quickly follows the
system, which builds in this evening and shifts the winds to the
southwest by morning. Low temperatures tonight will drop into the
upper 20s to lower 30s.

.LONG TERM...(Monday through Saturday)
Issued at 253 AM CST SUN JAN 25 2015

Monday and Tuesday look to be warm and dry as northwest flow
aloft is absent of any shortwaves and low level flow from the west
and south helps advect warmer air into the area. With models
showing 925MB temps warming to between 12C and 15C, have trended
highs warmer into the lower and middle 60s. Tuesday`s lows may
still be in the upper 20s and lower 30s due to a weak ridge axis
helping to decouple the boundary layer. So there could be some
decent radiational cooling with dry low levels still in place.

For Wednesday, models have trended towards tracking the remnant
Baja California shortwave a little further south moving it across
northern KS into Wednesday evening. The GFS/ECMWF/GEM struggle to
generate any precip with this waves as there appears to be limited
mid level moisture with the system and the boundary layer moisture
remaining capped in spite of the forcing. Because of this, have
maintained a dry forecast but will want to reevaluate this with
future runs. Wednesday morning looks to be the warmest as low level
warm air advection persists through the morning bringing dewpoints
in the upper 30s into eastern KS. This should set up another mild
afternoon since models hold off on any cold air advection until
late in the day.

Shortwave ridging should keep Thursday dry before a split flow
aloft develops for Friday and Saturday. The GFS has trended
towards a more separated pattern between a cutoff low over the
southwest and northwest flow across the northern plains. As a
result of less organized forcing, it has backed off on its QPF
prog. So with the ECMWF continuing to show dry weather with the
cutoff to the west and energy within the northwest flow staying to
the northeast of the forecast area, have opted to keep a dry
forecast through the end of the period. The split flow also
suggests the colder Canadian air may stay to the northeast as
well. So temps for Friday and Saturday have trended a little
warmer as the GFS and ECMWF appear to bring a weaker ridge of high
pressure into KS. A fair amount of uncertainty exists for Thursday
through Saturday, so I would not be surprised to see adjustments
to this forecast in the coming days.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1119 AM CST SUN JAN 25 2015

For the 18z TAFs, northwesterly winds will continue to gust upwards
of 25-35kts through early this afternoon before gradually
diminishing mid to late afternoon. MVFR cigs will likely persist
through much of the afternoon, but there is some certainty regarding
when this cloud cover with scatter out and/or lift to VFR
conditions. Have VFR conditions occurring by early this evening, but
will need to monitor the cloud cover trends.  Winds will back to the
west-southwest during the overnight hours.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY until 2 PM CST this afternoon FOR KSZ008>011-
020>023-034>038-054.

&&

$$

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





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