000
FXUS63 KTOP 152320
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
620 PM CDT Tue Apr 15 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Wednesday)
Issued at 353 PM CDT TUE APR 15 2014

Brief upper ridging taking place over the central portions of the
nation with thicker cirrus already returning to central Kansas a
shortwave pushes southeast into the northern Rockies. South winds
with some gusts returning to western and central portions of the
local area behind the cold, record-cold-setting surface ridge. Far
western areas just touching Red Flag criteria this hour with temps
warming nicely but dewpoints not changing much.

The upstream wave will keep the weather on the somewhat active side
through Wednesday afternoon. Strong pressure gradient develops over
the state tonight and persist into early Wednesday with 60kt low
level jet developing. Still looks like winds will drop a bit early
this evening before the jet develops but with the cirrus continuing
east, radiational cooling will be much more difficult to come by
compared to last night. Would not be surprised to see favored
elevated locations touch on advisory level winds at times overnight,
but still looks like the better opportunity for the stronger winds
comes when mixing can increase in the middle of the morning with the
jet pushing east through the day as the upper wave continues through
Nebraska. Looking like a pretty good chance at reaching wind
advisory levels at least on the sustained side but details on onset
and ending still somewhat uncertain with mid to late day decreases
expected. Models, similar to today, show increasing mixed layer dew
points through the day. Using the mixed layer, still dropped dews
several degrees, getting toward 20 percent at times. Though
confidence is not high, will go ahead with a fire weather watch for
northeast and east central Kansas based on customer input.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 353 PM CDT TUE APR 15 2014

The models have trended a little further south with the shortwave
and its QG forcing for Thursday. There still appears to be a decent
band of mid level frontogenesis moving across the area late
Wednesday night and through the day Thursday, but the models are now
showing more dry air on the north side of the system and struggling
to saturate the column for the frontogenesis to generate much precip
over the area. Because of the recent trends, have lowered POPs
during the day Thursday as well as start the chances later in the
night Wednesday night and end them sooner Thursday night. Soundings
still suggest the possibility for some snow to mix in with any
precip Thursday morning across the northern counties. However
confidence in precip has shaken somewhat due to recent model trends.
With models less amplified and a little more progressive with the
shortwave, think there could be some sunshine across north central
KS by the afternoon and have bumped up highs across the area into
the lower 50s.

For Friday southerly winds are expected to return with some warm
air advecting in from the south. Think this will help warm temps
into the lower and middle 60s. By Saturday and Sunday, the GFS and
ECMWF continue to show a southerly stream shortwave moving into the
plains. Initially there looks to be some weak instability Saturday
afternoon and Saturday evening so have kept the mention of
thunder. While the GFS and ECMWF are a little closer in handling
this shortwave, there remains some differences in timing and
confidence continues to be only average. Therefore have trended
POPs up but left them in the 40 to 50 percent range for Saturday
night through Sunday night. By Sunday the instability looks even
less impressive so have only rain showers mentioned in the
forecast for Sunday. There does not appear to be much in the way
of cold air due to the southern stream remaining split from the
northern stream. Therefore highs Saturday and Sunday are expected
to remain mild in the 60s and 70s.

Have a dry forecast going for Monday and Tuesday as mid level
ridging develops over the plains. Southerly low level flow should
bring warm air north and and the forecast has temps warming into
the mid and upper 70s for Tuesday. This may end up being a little
to cool if the GFS prog of 850 temps proves to be correct.

&&

.AVIATION...(For the 00Z TAFs through 00Z Wednesday Evening)
Issued at 615 PM CDT TUE APR 15 2014

VFR conditions anticipated through the taf period. Boundary layer
mixing this evening and overnight should be enough to keep the
smoke from restricting the visibilities although can not rule out
a brief period of MVFR vis reported by the ASOS due to smoke. At
this point think some gust will occur tonight with fairly steady
increases in speed aloft to somewhat mitigate LLWS despite speeds
around 60kt at 2000 feet AGL early tomorrow morning.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH from Wednesday morning through Wednesday
evening FOR KSZ010>012-022>024-026-036>040-054>056-058-059.

RED FLAG WARNING until 8 PM CDT this evening FOR KSZ008-020-034.

&&

$$

SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders