Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 232032
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
332 PM CDT Mon Mar 23 2015

.SHORT TERM...(This Evening through Tuesday)
Issued at 313 PM CDT MON MAR 23 2015

On Monday afternoon, negatively tilted upper trough axis extended
down the front range of the Rocky Mountains with a lead vort max and
associated strong 80-90 kt jet max clearly evident in WV imagery
extending into eastern CO. Lee side cyclogenesis was ongoing with
the strongest pressure falls in southeast CO under the jet.
Southerly LLJ was increasing ahead of the surface low and pulling
elevated moisture into southern KS while the mid 50s surface
dewpoints remained confined to west central OK with a developing
warm front extending across far northern OK. Moisture will continue
to advect north across KS this evening and overnight as the LLJ
increases and eventually veers. Will have rather persistent deep
vertical motion this evening associated with the upper level
features while widespread low level isentropic ascent is expected
with pockets of more focused lift. The first vort max passes through
by early Tues morning which could bring a lull in the activity but an
additional weak short wave trough is forecast to move overhead
shortly thereafter. Some guidance also focuses a stronger portion of
the LLJ into southeast and east central KS before sunrise Tuesday
and could enhance coverage in those area for a few hours.

The thermodynamics through the night are expected to be impacted by
the frequent convective overturning early on, and MUCAPE may be
limited by this. Also, as the steeper mid level lapse rates
eventually advect overhead late tonight with the elevated mixed
layer, the warmer base of the EML is likely to be dry and warm...
effectively capping the moist parcels and possibly shutting off the
bulk of precip near sunrise. All told, chances for convective
showers and embedded thunderstorms are good for much of the area to
see at least some rain overnight. The potential for severe hail now
appears low given the thermodynamic uncertainty, but the potential
for small hail is still there with some small chance for a few
quarter-size stones.

Tuesday remains very complex but is once again looking to be
relatively quiet from a severe weather perspective. While moisture
will be in place over east central KS, and strong dynamics will move
almost directly overhead, the timing of the elevated mixed layer
looks likely to leave the area nearly completely overcast, cool, and
possibly even with drizzle. There may be periods for which elevated
parcels become unstable with scattered showers and some storms
throughout the day (with the best chances for this north). Any
surface based parcels should stay capped in the local forecast area
though and severe storms appear unlikely. Winds appear likely to
become gusty with a drier airmass moving into areas generally south
of a Concordia to Emporia line during the afternoon. In any areas
that do not receive much rain tonight, fire danger may become
elevated by late Tuesday.

.LONG TERM...(Tuesday Night through Monday)
Issued at 313 PM CDT MON MAR 23 2015

By 00Z Wed the mid/upper level trough will be exiting the region
with widespread subsidence behind the wave. The ECMWF is the slowest
with the progression of the trough therefore develops precip in far
eastern KS in the early evening along the dry line. While the rest
of the models are much faster and develop the precip over MO. Expect
that the overnight hours will be dry before the next front quickly
approaches from the north driven by a stronger shortwave rotating
around the backside of the original wave over the upper Midwest and
northern plains. The questions will be how quickly the return flow
can develop north of the boundary south of the area that becomes a
warm front near the OK/KS state line on Wed morning. Showers and
thunderstorms will be possible during the day Wed as the moisture
transport and convergence maximizes along and near the I-35
corridor and portions of SE KS, although the instability will also
be in question. The NAM is the most aggressive bringing the warm
front and cape northward. Meanwhile the deep layer shear will be
well supportive of severe convection. As this second mid level
trough progresses southward over the plains mid level saturation
and lift increases over a deep layer of low level dry air.
Therefore do not expect much precip to make it to the surface in
association with this feature. The cold front will plow through
the forecast area by Wed evening and meet up with the warm front.
At this time the trough will also pass over the area, which
enhances the lift near the frontal zone through Wed night.


Dry air works back into the region behind this system as
strong northwest flow aloft drives the next piece of energy over the
area. Not sure about the quality of the low level moisture return
with regards to any precipitation. Cold air advection will also be
strong bringing sub freezing air back to the region. As the energy
passes over most of the profile should support snow with the
exception of the boundary layer temperatures. Have kept a mention of
slight chances for rain or snow Thur night, but accumulations will
be light if any. Friday morning and Saturday morning appear to be
dry for now and overnight lows drop into the 20s. During the day Sat
another piece of energy drops south within the highly amplitude
trough. Have not added any mention of precip during this time frame
due to low certainty.


&&

.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 232 PM CDT MON MAR 23 2015

Update at FOE in the short term as they are burning grass near the
airfield. Smoke from this fire is affecting visibility over the
airfield and will continue to do so through approximately 22Z.

VFR conditions are expected through the afternoon into early
evening with high confidence before the low pressure system off to the
southwest starts to become more organized and impacts the TAF
sites late evening and into the morning tomorrow. Activity will
begin out near the KMHK site after 0z as showers with the
potential for some thunderstorm activity after 3z followed by low
cigs into the IFR category. This will gradually shift East into
the KTOP/KFOE sites by 3-6z time frame. Confidence is on the low
end with actual thunderstorm coverage, but widespread showers and
low cigs are a very good likelihood as the atmosphere saturates
deeper throughout the evening and overnight.


&&

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

$$

SHORT TERM...Barjenbruch
LONG TERM...Sanders
AVIATION...Barjenbruch/Drake






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