Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KLSX 300902

Area Forecast Discussion
National Weather Service Saint Louis MO
302 AM CST Wed Nov 30 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 300 AM CST Wed Nov 30 2016

Focus today and tonight will be cloud cover, which in turn, will
have a large impact on temps.

Large stacked low over nrn Plains into Great Lakes region will
continue to control the weather pattern across the region. Area of
ST continues to move ewd early this morning. The main question
regarding this area of clouds is two fold. First, how far south will
the clouds propagate/develop and second, will the clouds break up
later today.

Based on the latest sat trends, believe much of the operational
guidance is too cloudy. Believe this trend continues thru the day.
The local WRF seems to do a better job currently, but believe it
does not suggest enuf clouds later today. Have therefore attempted
to go with a middle ground between these two solns. For areas
further north, chances of remaining cloudy all day increase
dramatically. However, believe the main cloud deck will remain just
north of the CWA, but uncertainty remains regarding placement.

Given these clouds trends, have trended below the cooler MOS across
the wrn and nrn portions of the CWA. However, given the wly flow and
a secondary area of clouds currently over OK region moving into the
area, have also trended twd the cooler guidance further south and
east, but not below.

As for tonight, with mixing expected to continue thru the night and
with clouds persisting thru much of the night, have trended warm.
That said, going forecast may not be cool enuf for low lying areas
that may decouple tonight. This is especially true for srn portions
of the CWA where the pressure gradient will be more relaxed and
winds lighter.


.LONG TERM...  (Thursday through Tuesday)
Issued at 300 AM CST Wed Nov 30 2016

System over Great Lakes region to finally move away from region, so
will see surface ridge build in over area by Thursday. Despite this,
will remain in west to northwest flow with mostly cloudy conditions
in the far north to mostly sunny far south through Friday. Highs
each day will be near normal, in the low 40s to low 50s.

By the weekend, the next weather system that has been strengthening
over the southwestern US, will begin to to approach region. First in
a series of shortwaves to lift out towards region and try to phase
in with northern stream system. Precipitation chances will be on
the increase especially Saturday night and Sunday morning.
Forecast soundings still indicating mostly rain with snow mixed in
at times with this system. No accumulation expected.

GFS is still the most consistent model and keeps weak ridging in on
Monday before next system slides in from the southwest, phasing with
the next in a series of northern stream shortwaves. Strength, timing
and placement still hard to pin down, so kept chance pops going
Monday night, tapering off Tuesday morning. Precipitation will
mainly be in the form of rain once again, with some snow mixed in a


.AVIATION...  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1133 PM CST Tue Nov 29 2016

VFR for the first 0-6 hours at all TAF sites. An expansive
stratocu deck will wrap around a stacked low pressure system and
reach the terminals after 30/12z. It is possible that cigs may
still be MVFR for a few hours at KCOU and KUIN before sufficient
daytime mixing causes cigs to rise to low-end VFR. The cloud bases
are expected to be VFR by the time the stratocu deck reaches the
St. Louis metro area. Westerly winds will increase and become
gusty by mid/late morning, then diminish after sunset.


Saint Louis     46  35  46  31 /   5   5   0   0
Quincy          41  30  42  29 /   5   5   0   5
Columbia        44  29  44  28 /   5   5   0   0
Jefferson City  45  30  45  28 /   5   5   0   0
Salem           47  32  45  30 /   0   0   0   0
Farmington      48  33  47  30 /   0   0   0   0



WFO LSX is the U.S. government's official web portal to all federal, state and local government web resources and services.