Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 282011
Area Forecast Discussion
National Weather Service Saint Louis MO
311 PM CDT WED SEP 28 2016
.SHORT TERM... (Through Late Tonight)
Issued at 140 PM CDT Wed Sep 28 2016
Not a lot of change for the forecast tonight. The upper low
currently over the OH Valley will more or less remain in place.
The sfc cdfnt will continue to push swd with some relaxation of
the sfc pressure gradient across wrn portions of the CWA. This
will allow winds to diminish somewhat this evening with sunset,
but still expect mixing to continue across the region thru
tonight. This shud prevent fog from developing and will limit
radiational cooling. However, with continued CAA tonight, still
expect temps to drop into the 40s across much of the area.
.LONG TERM... (Thursday through Next Wednesday)
Issued at 308 PM CDT Wed Sep 28 2016
Upper level low will continue sit and spin over the Ohio Valley,
maybe even retrograde back to the northwest a bit through the end of
the work week and into the first part of the weekend. So will see
scattered shower activity as shortwaves rotate around upper low,
mainly along and east of Mississippi River. Some weak instability
on Friday afternoon, so added slight chance mention of thunderstorms
in the far eastern portions of forecast area.
With cyclonic flow over region, temperatures to remain a bit below
normal through Saturday. Then upper low finally begins to lift to
the northeast away from region by Saturday night. Temperatures to
moderate as surface flow becomes southerly once again with highs in
the upper 70s to low 80s by Monday.
Beyond that, the next chance for rain will be late in the extended,
Tuesday night and Wednesday, as a strong cold front approaches from
the Central Plains.
.AVIATION... (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1219 PM CDT Wed Sep 28 2016
Strong nly winds will continue thru the afternoon, diminishing
this evening with sunset. Field of MVFR cigs across nrn IL and IA
shud continue to break up and lift as it attempts to move south
this afternoon. Nly winds will pick up again Thurs morning with an
area of MVFR cigs impacting STL/CPS during the late morning hours.
Have kept out of SUS for now as it looks questionable as to if
these cigs will reach STL/CPS. Have kept in the TAF for now as
confidence is not high enuf to remove.
With a clear sky tonight further west, namely COU area, is some
potential for fog development. However, with mixing anticipated
thru the night, fog threat shud be further west.
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 53 70 56 70 / 5 20 10 40
Quincy 48 70 54 70 / 10 10 10 20
Columbia 47 71 52 71 / 0 5 5 5
Jefferson City 47 71 52 72 / 0 5 5 5
Salem 51 68 54 69 / 10 30 30 50
Farmington 46 67 53 68 / 0 10 10 30