Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 050819
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
319 AM CDT MON OCT 5 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 317 AM CDT Mon Oct 5 2015
Look for decreasing low clouds this morning but a gradual increase
in mid/high clouds by afternoon. The lack of extensive stratus
should lead to warmer afternoon high temperatures across the region
today compared to yesterday. Winds will remain out of the north or
northeast due to the influence of a ridge axis to the north.
.LONG TERM: (Tonight through Sunday)
Issued at 317 AM CDT Mon Oct 5 2015
Still appears tranquil weather will persist for the CWA heading
into midweek as weak ridging holds over the central CONUS. The
primary forecast question through Wednesday is temperature
specifics. AMS will be quite mild for early October with 850MB
temps roughly between +10 to +13C, but models are indicating
several waves of cloudiness...first from moisture streaming north
from Mexico, then with additional moisture advecting east from
Not certain as to the exact extent of this cloudiness, but models do
seem to agree that it will not be the insolation-killing low
cloudiness that made for a very chilly Sunday afternoon along and
west of the Mississippi River, but rather cloudiness of the mid
and high level variety. Given the extent of cloudiness suggested
by forecast soundings for Tuesday I`ve trimmed back temps a bit to
reflect roughly a 15-20 degree warmup from early morning
lows...which puts them in line with conditional climatology values
with a mid cloud deck for early October. Clouds should be less
extensive on Wednesday, and this should allow highs to push into
the 75-80 degree range.
After nearly a week of stalled weather features over the eastern two-
thirds of the CONUS, the GFS, ECMWF, and GEM all remain in fairly
good agreement that the upper air pattern will become much more
progressive during the latter half of the week.
A strong shortwave in the westerlies will dip southeast and push
through the mid and upper Mississippi Valley on Thursday and
Thursday night, bringing a threat of showers and thunderstorms to
the entire forecast area. However, by Friday the GFS has the
shortwave trof east of the area, while the ECMWF and GEM slow the
movement of this feature over the mid-Mississippi Valley. Based on
this, will maintain some PoPs over at least the southeast half of
the CWA on Friday. Temperatures will remain very mild on Thursday,
with a noticeable cool down in the wake of the front on Friday.
Ridging is then expected to build back into the central U.S. over
the weekend as shortwave continues to dig into the eastern part of
the country. Temps over our area should rebound in response,
with highs well in the 70s once again by Sunday.
.AVIATION: (For the 00z TAFs through 00z Monday Evening)
Issued at 629 PM CDT Sun Oct 4 2015
MVFR cigs are expected to persist overnight at UIN/COU and lower.
UIN may have IFR cigs around sunrise Mon morning. Expect cigs to
be slow to lift eventually reaching VFR during the afternoon hrs.
Specifics for KSTL/KSUS/KCPS: A difficult forecast for the next 24
to 30 hrs. Edge of clouds has made it W of STL/CPS despite nly
low level winds and sunset. Can not rule out edge pushing a little
further W, but expect MVFR cigs to return to terminals this eve.
Regardless, currently anticipate IFR cigs developing late tonight
into Mon morning with cigs slowly lifting thru the day Mon. IFR
cigs may last longer than currently fcst, but will monitor trends
and update as needed.
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 75 59 77 62 / 5 5 5 5
Quincy 70 56 73 57 / 5 10 10 5
Columbia 71 56 73 58 / 5 10 10 5
Jefferson City 72 56 75 57 / 5 10 10 5
Salem 77 58 77 57 / 5 10 0 5
Farmington 73 57 76 56 / 5 5 5 5