Area forecast discussion
National Weather Service Paducah Kentucky
326 am CDT Wednesday may 22 2013
Short term...(today through Friday night)
issued at 317 am CDT Wednesday may 22 2013
Lower tropopause S-swlys will continue to pump ample moisture through the
column today. Diurnal heating will sufficiently destabilize the
daytime atmos to support continued chance of showers/storms. So
with moisture/instability sufficiently in place...it should be
acted upon as height falls occur with energy pinwheeling around
base of mean long wave trough today into Thursday. This trend more
or less continues with a primary and then 2ndary upper trough
passage over the next 24-48 hours. This much of the forecast has
been basically unchanged for the last 3 days and remains so.
The change in weather regime will occur Thursday night into Friday
as we get into the Post system/wake airmass which will be
pleasantly cooler and drier air working down the column. The
result will be middle week muggy 80s/60s transitioning to comfortable
70s/50s by weeks end.
Long term...(saturday through tuesday)
issued at 317 am CDT Wednesday may 22 2013
The weekend will start off dry and mild with high pressure ridging
at the surface and aloft. A warming trend will take place late in
the weekend into early next week as southerly low level flow
develops on the back side of the departing high.
Models remain stubbornly uncompromising in their handling of a
baroclinic zone forecast to develop along the northern periphery of
the forecast area late in the weekend. As a result...forecast
confidence early next week is rather low...especially with regard to
the chance for showers and thunderstorms. The operational European model (ecmwf)
develops the frontal boundary much further south than the GFS and is
therefore much wetter than the GFS. An inspection of the ensemble
mean of the European model (ecmwf) and GFS certainly lends support to the scenario
portrayed by the operational GFS.
Consequently...the greatest potential for showers and thunderstorms
Sunday into Monday should reside along and north of the baroclinic
zone...which would imply the northern half of the forecast area.
Meanwhile...mainly dry weather is expected across southern portions
of southeast Missouri and much of western Kentucky where a middle level
capping inversion should be more pronounced. The going forecast
handles this well...so little change was necessary.
Will keep temperatures above the initialized guidance blend through
much of the period. This yields highs in the lower to middle 80s by
Monday and Tuesday...with lows in the lower to middle 60s.
&&
Aviation...
issued at 317 am CDT Wednesday may 22 2013
Most recent band of showers moving across eastern taf sites
(kevv/kowb) at this writing will temporarily restrict ceilings to MVFR
through early am. New development should occur after
sunrise...with low VFR ceilings restricted to MVFR at times in
-shra/-tsra which likewise could produce MVFR restricted visibilities. A
general decrease in overall coverage through the latter half of the
terminal effective valid time lends toward a vicinity approach for
the lingering pop chance.
&&
Pah watches/warnings/advisories...
Illinois...none.
MO...none.
In...none.
Kentucky...none.
&&
$$
