Area forecast discussion
National Weather Service Topeka Kansas
642 am CDT Monday may 20 2013
Short term...(today and tonight)
issued at 323 am CDT Monday may 20 2013
Phasing pair of upper lows continue to merge and spin over the
northern plains...rotating pieces of energy around all quads as it
does so. 80-100kt upper jet moving eastward out of The Four
Corners region into Texas/OK panhandles at this time. Surface pressure plot is
more diffuse over eastern Kansas at this time...as convection has sent outflow
out in all directions. More consistent northwest wind frontal pattern
shows up over southeast Nebraska into northwest Kansas.
Weather conditions today will be impacted by the wake of
departing convection. Satellite trends do suggest clearing behind
this mornings round which would help increase instability through
the day. NAM surface pattern begins to suggest an inverted trough
setting up around 18z over the i35 corridor in eastern Kansas...also
bringing the upper jet over the area at the same time before a
sharp boundary has a chance to establish itself. Still have
respectable severe weather parameters...with mu cape values from
mhk westward of 1500-2500k/kg in the southeast by 18z. Soundings
suggest cap erodes in the later afternoon when 0-6km bulk shear
vectors are in the 50kt range. Primary concerns would be for hail
and damaging winds. Tornado threat will depend on how the low
level winds set up...but at this time appears better backing will
be in the far southeast or even further southeast out of our forecast area.
Also think storms will have a better chance into southeast Kansas/SW MO and
Oklahoma where instability is better and jet dynamics more
favorable. Will have to monitor where better convergence sets up
by this afternoon...but at this time have painted an area across
the southeast for severe potential. May see some storms in the western
counties as well this afternoon as another piece of energy rotates
into that area...but do not think those storms would be severe.
Thunderstorm chances push southeast out of the forecast area through the
night Tuesday night with diminishing precipitation chances northwest to southeast. Lows
drop into the 50s as stronger push of cooler air moves eastward.
Long term...(tuesday through sunday)
issued at 323 am CDT Monday may 20 2013
Kept a dry forecast for later Tuesday through Wednesday night as
the upper system moves slowly eastward. Highs in the 70s expected
with lows in the 50s. By Thursday...southwesterly flow over the SW
US begins sending shortwave troughs into the ridge over the Central
Plains...over the boundary residing over the High Plains. This
brings chances for precipitation each day and although do not
expect rain all day every day do anticipate occasional showers and
storms through Sunday. High temperatures return toward 80 by the
weekend.
&&
Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 640 am CDT Monday may 20 2013
VFR conditions are expected through the next 24 hours...however
there will be a chance for convection to the south of the
terminals later this afternoon. Expect those storms to remain well
south of the terminals...but will continue to monitor the
conditions should storms fire a little north of the expected area.
Jl
&&
Top watches/warnings/advisories...
none.
&&
$$
Short term...67
long term...67
aviation...Leighton
