Area forecast discussion
National Weather Service Topeka Kansas
1237 PM CDT Thursday may 23 2013
Short term...(today and tonight)
issued at 230 am CDT Thursday may 23 2013
The old upper system continues to slide east and weaken over the
western Great Lakes...with 0z 500mb height change observations
depicting weak to moderate rises across the plains. Low level
ridging was taking shape across the Central Plains...with south
winds taking hold over the southern High Plains. A shrinking stratus
deck was oozing south through Nebraska early this morning.
Shallow nature to the low clouds and increasing low level isentropic
downglide should allow the invading stratus to dissipate this
morning though more could redevelop with daytime heating. Temperatures
again stay on the cool side with north winds veering to the east
through the day. Further veering on track for tonight as Lee low
pressure begins to take shape and upper heights continue to rise.
Middle level moisture increases a bit in the west with modest
isentropic upglide via weak winds and elevated cape developing. This
could be enough to usher any High Plains convection into north
central Kansas late tonight...though confidence in the former making
it this far north is not very high.
Long term...(friday through wednesday)
issued at 230 am CDT Thursday may 23 2013
Despite the fact that there are chances for precipitation through
the forecast for Friday through next Wednesday...rest assured it
wont be raining all day every day. Convection is being driven by
small waves in the flow that are difficult to time...by the
nocturnal low level jet...as well as the boundaries that the convection
leaves behind to regenerate chances for the following day...and
other mesoscale interactions related to all these features. Will
likely be able to time precipitation chances better in a window
closer to their time scales...by a matter of a day or two rather
than several days out.
First feature is a frontal boundary draped north/S from the Dakotas
into Nebraska...the southern edge of which clips across the
forecast area through the day on Friday. The following night low level jet
slides convection along the north and to the NE of the County Warning Area and may
run through our northern counties. Boundary from this mesoscale convective system could then
lay up across the area on Saturday afternoon and regenerate
storms...with yet another weak wave riding across western/ctrl Kansas and
bringing another chance for ts Saturday night into Sunday morning.
May catch a break between waves on Sunday afternoon before
potential for another wave to lift across the western through northern
counties into Monday. Some suggestion that ridge amplifies Tuesday
into Wednesday in the European model (ecmwf)...although GFS amplifies it farther to
the east of our forecast area and keeps the damp pattern going for another
day. After a cooler day in the 70s on Friday...as surface ridge shifts
east and warm air advection returns...should southeast a shift back toward the lower 80s
for highs across the area. If the ridge can amplify...may see
warmer temperatures toward later next week.
&&
Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1236 PM CDT Thursday may 23 2013
For the 18z tafs...MVFR ceilings continued to blanket the region early
this afternoon but ceilings should begin to lift to low-end VFR by middle
to late afternoon. One issue of uncertainty is whether or not the
taf sites will experience MVFR ceilings once again Friday morning. There
are still some model discrepancies regarding this cloud cover so
have kept any mention out of ktop/kfoe tafs at this time...but there is
somewhat higher confidence out toward kmhk so have gone ahead with a
mention. Winds through the period will veer from northeast to
southeast as surface high pressure sinks southward into the area.
&&
Top watches/warnings/advisories...
none.
&&
$$
Short term...65
long term...67
aviation...hennecke
