Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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
FXUS63 KLSX 161800

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
100 PM CDT SUN OCT 16 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 350 AM CDT Sun Oct 16 2016

Showers and storms were moving through parts of west central IL
early this morning, north of STL in a region of low level moisture
convergence on the nose of a southwesterly low level jet.  Scattered
showers and storms will continue north and east of STL this morning,
but should shift east of our forecast area by afternoon as the low
level jet shifts into the Ohio Valley region and a weak frontal
boundary shifts north of our area as a warm front.  The warming
trend will continue with southerly surface winds and gradually
rising 850 mb temperatures.  Highs today will be at least 15 degrees
above normal.  Mild temperatures can be expected tonight with
continued southerly surface winds, strong southwesterly low level
winds, and relatively high surface dew points.  Lows tonight will be
at least 20 degrees above normal.


.LONG TERM...  (Monday through Saturday)
Issued at 350 AM CDT Sun Oct 16 2016

RIDGE aloft is expected to persist over the south-central and
southeastern CONUS into the middle of the week.  At the same time,
pieces of energy are expected to continue to come ashore into the
Pacific Northwest with the final piece holding off until Tuesday
morning.  Overall, a warm and dry period is expected thru Tuesday as
the RIDGE axis located just to our south is largely expected to win
out and deflect these Pacific disturbances to our north during this

Temperatures thru Tuesday will be unseasonably warm, with max temps
above 80 each day (15 to 25 degrees above average), exceeding record
max temps on Monday at all climate locations and approaching in STL
metro on Tuesday.  See the CLIMATE section for more info.  Monday
daytime also is looking quite windy, with gusts of 30-35 mph
expected areawide, possibly to 40mph for sections of northeast and
central MO.

A surface cold front is expected to at least enter our region on
Tuesday--with all models now signing on to what the EC initially
showed 24hrs ago--and that is a much slower progression thru our
region, with it still anticipated to be upstream of STL metro by
nightfall Tuesday.  The atmosphere should initially be too capped
for any pcpn to form along the front, but as moisture in the column
increases ahead of the front, the increase should be sufficient
to breakout showers and storms later on Tuesday night.

This better model consensus continues thru the middle of the week
now with the surface front stalling--where it is by nightfall
Tuesday night should be where it remains thru much of Wednesday with
chances for showers and storms persisting.  There remains some model
spread on exactly where the front stalls but it appears the best bet
will be near or just south of I-70.  This is well reflective of the
lack of any turn in the mid level flow, which remains from the W-SW
thru this time.

The GFS and EC have come into much better agreement on the last
piece of Pacific energy that should affect our region late Wednesday
and into early Thursday, with the less wrapped up and more
progressive EC seeming to win the argument from 24hrs prior.  This
looks far less extreme on pcpn but still enough to justify likely
PoPs for most Wednesday night and somewhat less on Thursday.

The end of the week and into next weekend looks cool and dry with NW
flow aloft and a frontal passage by Thursday and N-NW surface flow

There is still some possibility of another shift in the mid-late
week forecast in the next 24hrs as all of the pieces come ashore
from the Pac NW, so stay tuned.



.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1231 PM CDT Sun Oct 16 2016

VFR through the period. Wind speeds will increase overnight in
response to a tightening pressure gradient. Expect wind gusts of
20-30 kts after 17/14z once stronger winds aloft begin mixing
down to the surface.



Issued at 343 AM CDT Thu Oct 13 2016

Unseasonably warm conditions are expected to persist through
the weekend and into early next week and may approach record
territory. The following lists record high temperatures and
record high minimum temperatures for St. Louis, Columbia and
Quincy from Sunday to Tuesday.

St. LouisColumbiaQuincy

10/16   High Low:65/196566/196867/1968

10/17High Low:66/199864/196566/1935

Tuesday High:87/195386/195387/1924
10/18High Low:68/198564/197166/1938




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