Area forecast discussion...updated aviation
National Weather Service St Louis MO
1015 PM CDT Tuesday Jun 18 2013
Update...
issued at 902 PM CDT Tuesday Jun 18 2013
Weak cold front has slowly pushed through the area this evening
and is currently over far southern counties. Front will continue
to sag south tonight. Trimmed probability of precipitation back as isolated showers/storms
along front and previous outflow boundaries have dissipated in
part due to loss of instability/daylight heating. Otherwise...only
cosmetic changes made to tonight's forecast.
Gosselin
&&
Short term...(through late tonight)
issued at 243 PM CDT Tuesday Jun 18 2013
Focus tonight will be probability of precipitation...again.
This portion of the afd is beginning to sound like a broken record.
Have increased probability of precipitation through early this evening. Expect ongoing thunderstorms and rain to
dissipate and/or move southeastward out of the area by middle to late this
evening.
Models do depict an area of 850h convergence across portions of north
central MO late tonight into Wednesday morning. The NAM is...so far...the
only model that produces precipitation with this feature. Other models suggest
middle level temperatures will be too warm to allow for convection. Will
therefore keep the period after midnight dry for now.
Very minor adjustments made to the previous forecast. Can not rule out
some fog development late tonight...especially across central MO where drier
air will struggle to advect into the region.
Tilly
Long term...(wednesday through next tuesday)
issued at 243 PM CDT Tuesday Jun 18 2013
Wednesday through Friday...
dry and seasonal weather is expected for Wednesday with light winds
from the east as the surface ridge dominates the region. Wednesday
night a 50kt low level jet will intensify across the plains and
interact with a shortwave topping the upper level ridge. The GFS
depicts a deeper shortwave when compared to the NAM and therefore
develops showers and thunderstorms across central Nebraska and east
central Kansas. The question is how far east will the convection
travel Wednesday night into Thursday morning as the low level jet
veers. For now have maintained slight chance probability of precipitation across central and
northeast Missouri late Wednesday night...but feel the better
chances will remain west of the County Warning Area.
Meanwhile...at the surface a warm front will be pushing northeast
across the region on Thursday. Instability will increase throughout
the day bringing a greater chance for thunderstorms to the area.
The warm front should move northeast of the region as the upper
ridge builds over the County Warning Area. Deep mixing and a southerly surface wind
will allow temperatures to rise above normal into the lower 90s.
Saturday through Tuesday...
southwest to northeast orientated upper level ridge to dominate the
center of the nation this weekend...with above normal temperatures
and limited chances of precipitation. The pattern will begin to
break down by early next week as the flow becomes more zonal and the
upper level ridge reestablishes itself to our west.
Grana
&&
Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1010 PM CDT Tuesday Jun 18 2013
VFR conditions are expected at most taf sites for the majority of
the taf period with light winds becoming southeasterly tomorrow. The exception
may be at kcou later tonight if the cirrus clouds clear out before
a drier air mass arrives at low levels. The resulting radiational
cooling conditions could produce a few hours of MVFR fog or
stratus before conditions improve by mid-morning.
Specifics for kstl...VFR through the period with light winds becoming
southeasterly tomorrow.
Kanofsky
&&
Lsx watches/warnings/advisories...
MO...none.
Illinois...none.
&&
$$
Weather forecast office lsx
