Area forecast discussion
National Weather Service Topeka Kansas
333 PM CDT Tuesday Jun 18 2013
Short term...(this evening through wednesday)
issued at 317 PM CDT Tuesday Jun 18 2013
this afternoon through Wednesday
A decaying mesoscale convective system and upper level wave was slowly tracking southeastward
into southeast Nebraska during the Tuesday morning hours. An outflow
boundary generated by this complex gradually crossed the Kansas and
Nebraska line after 18z. Further south over east central Kansas...a
weak frontal boundary stretched near the Interstate 70 corridor.
Dewpoints south of this boundary were into the lower and middle 60s
with a decent moisture gradient set up across the area. While 0-6 km
bulk shear will continue to be modest at around 25 kts...a limiting
cap and decent instability will continue to promote isolated
thunderstorms developing through the late afternoon and evening hours.
Mesoscale features such as the outflow boundary and moisture
gradient has aided in a few isolated storms to become severe with
strong winds and hail near a quarter size. Most of the convection
will grow rapidly due to the steep middle level lapse rates but with
lack of decent middle level shear should not sustain itself long with
small hail and localized gusty winds. As daytime heating winds
down...storms should gradually diminish after sunset.
For Tuesday evening...expect to see additional convection develop
over western Kansas in conjunction with a decent middle level vorticity maximum.
Models have trended this convection slower as it translates eastward
into central Kansas. Have followed suit with removing precipitation chances
until Wednesday morning where I kept slight probability of precipitation over north central
Kansas. Temperatures in the middle 60s and light winds still remain on
track with minimal changes made.
On Wednesday afternoon do not expect widespread rainfall throughout
the afternoon with still some uncertainty to where storms will
develop. Models have handled quantitative precipitation forecast output poorly...however atmosphere
is weakly capped with around 2000 j/kg of cape and 0-6 km bulk shear
near 25 knots. The associated vorticity maximum should also provide the upper
level support to maintain any updrafts. Widespread severe weather is
not anticipated however a few isolated/marginal severe storms cannot be
ruled out. Decent southerly return flow around 10 to 20 kts with
gusts around 25 kts allowed highs to be increased a few degrees in
the low to middle 80s.
Long term...(wednesday night through tuesday)
issued at 317 PM CDT Tuesday Jun 18 2013
Wednesday night-Fri...next chance for thunderstorms looks to come
overnight Wednesday night into Thursday morning as pattern transitions to
southwesterly and brings isentropic lift across the area as it does
so. Precipitation chances continue into the morning hours then will end
probability of precipitation west to east by Thursday afternoon as warm middle level temperatures and
cap move in. Highs climb from upper 80s to the lower to middle 90s
by Friday.
Saturday through Tuesday...upper level trough will continue to
lift through the northern plains through the weekend while a
ridges begins to build westward through the Southern Plains. There
will be a slight chance of showers and thunderstorms on Saturday
night as a front slides through Nebraska although the better
chances are north of the area. That front appears to lift north
into the northern plains behind the upper wave. The next chances
for storms looks to be on Sunday night and Monday morning as a
shortwave lifts northeast within the southwesterly middle level flow.
Into next week the upper ridge continues to build over the inner
mountain west. This will allow for a quiet period at least through
Tuesday. Temperatures will be above normal with highs in the low
to middle 90s...lows in the middle 70s through the entire period.
&&
Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1214 PM CDT Tuesday Jun 18 2013
VFR prevails at ktop/kfoe/kmhk with light northerly winds shifting
towards the east after 21z. Mentioned thunderstorms in the vicinity as there is a possibility of
thunderstorms and rain developing and impacting sites after 21z. Any precipitation should be
clear of the area after 01z at kmhk and 02z at ktop/kfoe. Too far out to
mention however there is low end chance of thunderstorms and rain developing west of
kmhk Wednesday morning. Will review at next issuance.
&&
Top watches/warnings/advisories...
none.
&&
$$
Short term...Bowen
long term...67/Sanders
aviation...Bowen
