Special Weather Statement, NWS St. Louis, MO

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
648 PM CDT Thu Oct 10 2019

.SHORT TERM...  (Through Late Friday Night)
Issued at 330 PM CDT Thu Oct 10 2019

Showers and embedded thunderstorms are ongoing across south-central
Missouri north/northeastward into western Illinois. This activity
will continue to move northeast with a small net west to east
movement of the back edge of the steadier precipitation. The actual
cold front as of 2000 UTC is located across far eastern Kansas.
Additional showers and thunderstorms are beginning to initiate along
this boundary, but very limited instability along with stronger
forcing for low-level ascent displaced to the east and mid/upper
level ascent further to the northwest suggests a fine line of
showers is likely with the actual frontal passage. The best chance
of showers and embedded thunderstorms is expected to largely remain
in a similar area where the current activity is falling due to
persistent low-level warm/moist advection interacting with several
midlevel disturbances as seen on latest water vapor imagery. The
main impact of the overnight precipitation activity will be to
provide beneficial rain to areas that were very dry during the month
of September and early October. Heaviest amounts tonight also should
be displaced slightly southeastward of this morning's 1-2" which
fell across portions of central Missouri. Due to ongoing showers and
storms, any severe threat this evening looks minimal due to lack of
instability.

The timing of the cold front is about an hour or two faster than
thought 24 hours ago. By 0600 UTC, the boundary is forecast to be
near KVIH>>KUIN and by daybreak KFAM>>K3LF. The front should clear
the CWA by mid morning on Friday. Behind the front, winds will
sharply veer to the northwest. Temperatures will drop rapidly in the
immediate aftermath, on the order of 10-20 degrees within a few
hours. Temperatures will steady out then by early afternoon, with a
slight rise for portions of central and northeastern Missouri.
Overall, it will look and feel like fall with temperatures areawide
in the afternoon mainly between 45-50 degrees. These temperatures
combined with gusty northwest winds and lingering light rain will
make it feel quite a bit cooler than the actual air temperature too.

The well below normal temperatures will remain the story on Friday
night. The coldest night this young fall season is in store beneath
a clear sky. Lows should drop back into the low to mid 30s areawide,
with favored terrain possibly bottoming out just below the freezing
mark. Frost development still very much looks in doubt due to
increasing west/southwest winds and very dry dewpoints. Because of
these factors, elected to keep frost mention out for now. However,
one area that we will have to watch more carefully is across
southeast Missouri due to the proximity of the surface ridge axis
and local climatology where favored valleys cool more efficiently
than surrounding terrain.

Gosselin

.LONG TERM...  (Saturday through Next Thursday)
Issued at 330 PM CDT Thu Oct 10 2019

Temperatures will rebound nicely on Saturday due to west/southwest
winds and plentiful sunshine. High temperatures should be in the
upper 50s to low 60s, which is about 5-7 degrees below normal for
the date. The aforementioned west/southwest winds will also be
gusty, on the order of 30-35mph for the most of northeast Missouri
and west-central Illinois.

Dry, seasonable weather is expected to continue heading into early
next week as the deep, closed low nearly anchored across the
northern Plains finally moves slowly eastward. The next chance of
showers and thunderstorms is late Monday night through Tuesday
evening associated with another cold frontal passage. Behind this
front, a return to below normal temperatures is forecast with highs
mostly in the 50s to low 60s Wednesday and Thursday. Overnight lows
are also expected to be cooler than normal, but generally in the mid
30s to low 40s.

Gosselin

&&

.AVIATION...  (For the 00z TAFs through 00z Friday Evening)
Issued at 647 PM CDT Thu Oct 10 2019

Persistent area of showers and a few thunderstorms will continue
for the STL Metro TAFs through the evening with a few breaks
possible. Some of this convection will attempt to fill in further
west into COU and UIN later this evening. A cold front is expected
to sweep through the area overnight, beginning around 05z for COU,
07z for UIN, and 10-11z for the STL metro sites. Cold FROPA should
usher in IFR CIGs for several hours and maintain light rain until
around sunrise. Look for gradual drying and slowly improving
conditions to VFR heading through Friday morning and into midday
from west to east. The cold front will also shift winds from the
W-NW with gusts to 25kts for much of the day on Friday, not
diminishing until close to sunset.

SPECIFICS FOR KSTL: Persistent thunderstorms with gusty winds will
continue to be an issue until around 02z when thunder coverage
should have lessened. Edged FROPA a bit earlier than previous
TAF but no major changes from last TAF issuance.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

WFO LSX

Hazardous Weather Outlook
National Weather Service Saint Louis MO
344 PM CDT Thu Oct 10 2019

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-112045-
Adams IL-Audrain MO-Bond IL-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Clinton IL-Cole MO-Crawford MO-Fayette IL-Franklin MO-Gasconade MO-
Greene IL-Iron MO-Jefferson MO-Jersey IL-Knox MO-Lewis MO-Lincoln MO-
Macoupin IL-Madison IL-Madison MO-Marion IL-Marion MO-Moniteau MO-
Monroe IL-Monroe MO-Montgomery IL-Montgomery MO-Osage MO-Pike IL-
Pike MO-Ralls MO-Randolph IL-Reynolds MO-Saint Charles MO-
Saint Clair IL-Saint Francois MO-Saint Louis City MO-Saint Louis MO-
Sainte Genevieve MO-Shelby MO-Warren MO-Washington IL-Washington MO-
344 PM CDT Thu Oct 10 2019

This Hazardous Weather Outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Tonight.

Showers and thunderstorms are likely overnight tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

There is a slight chance of thunderstorms Friday morning across southwest
Illinois.

Another chance of showers and storms exists across the area Tuesday
afternoon ahead of another cold front.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated tonight.

Gosselin

Special Weather Statement
National Weather Service St Louis MO
815 PM CDT Thu Oct 10 2019

MOZ047>049-110200-
Moniteau MO-Cole MO-Osage MO-
815 PM CDT Thu Oct 10 2019

...SIGNIFICANT WEATHER ADVISORY FOR COLE...SOUTHWESTERN OSAGE AND
SOUTH CENTRAL MONITEAU COUNTIES UNTIL 900 PM CDT...

At 815 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles northeast of Eldon to 10 miles
southwest of Hickory Hill to near Osage Beach. Movement was east at
35 mph.

Pea size hail and wind gusts up to 50 mph will be possible with these
storms.

Locations impacted include...
Jefferson City, Wardsville, Taos, Westphalia, St. Thomas, Brazito,
Hickory Hill, Meta, Eugene, Argyle, Schubert, Koeltztown, Osage City,
Osage Bend and Enon.

This also includes Clarks Hill/Norton Historic Site.

LAT...LON 3847 9256 3857 9215 3856 9209 3856 9205
      3857 9200 3836 9195 3829 9198 3829 9219
      3834 9220 3832 9226 3834 9229 3834 9241
      3843 9241 3843 9255
TIME...MOT...LOC 0115Z 259DEG 31KT 3841 9249 3828 9246 3812 9258

BSH