Area forecast discussion...updated aviation
National Weather Service St Louis MO
559 am CDT Wednesday may 22 2013
Short term...(through tonight)
issued at 138 am CDT Wednesday may 22 2013
Focus continues to be precipitation chances today.
Given model performance over the past 24 hours...have lower than
normal confidence in forecast for today. To add to this low
confidence...the latest model data suggests thunderstorms and rain should be much more
widespread across southern MO into Arkansas associated with the rather strong
short wave currently rounding the base of the upper low. This short wave still
has the potential to produce some precipitation later this morning if the
low level jet can respond behind the line of convection across the southern US.
Another short wave currently over southern Nebraska is forecasted to round the base of
the upper low later today. This short wave should help initiate isod to scattered
convection this afternoon along the cold front. Believe best chances
will be across southeast MO and SW/S cntl Illinois where low level lapse rates
will be steeper. Any precipitation that develop this afternoon should
dissipate quickly with sunset.
As for temperatures...trended at or below coolest MOS across the northwestern third of
the County Warning Area and near the warmest MOS elsewhere for today. Trended a
little cooler tonight as the County Warning Area will be behind the cold front.
However...did not go too much cooler as cloud cover should help kept
temperatures a little warmer.
Long term...(thursday through tuesday)
issued at 334 am CDT Wednesday may 22 2013
Focus through Friday will be temperatures with County Warning Area mainly dry until the
weekend.
Models are in good agreement with surface ridge building into the area
and below average temperatures expected through the remainder of the week.
Still...have trended toward the warmer guidance as it is still late
may and believe much sun will still allow temperatures to warm quickly.
Focus then turns to precipitation chances beginning this weekend. Models
remain in good agreement with the surface ridge moving eastward with an
upper level ridge building into the area on Sat. Beginning next
week...models differ regarding placement of features...but agree in
the overall idea. A surface fnt should become stationary somewhere
across the Midwest. Too much uncertainty exists as to where this
fnt will set up...so have kept probability of precipitation fairly low for now except
where models are in agreement for precipitation in timing and placement.
Have temperatures moderating next week and slowly trending warmer through
the week.
Tilly
&&
Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 554 am CDT Wednesday may 22 2013
VFR conditions expected today ahead of a slow moving cold front.
Could see a few showers develop along the front this afternoon
across eastern Missouri and into Illinois. Otherwise...southwest
wind to become west with passage of the front.
MVFR ceilings will build south late tonight with wind shifting to
the northwest Thursday morning.
Specifics for kstl...
VFR today. Cold front passes terminal around 18z with possibly a
shower. Otherwise...wind to shift from southwest to west this
afternoon. MVFR cieilng to build south into the area on Thursday
with wind turning to the northwest.
Cvking
&&
Lsx watches/warnings/advisories...
MO...none.
Illinois...none.
&&
$$
Weather forecast office lsx
