Severe Thunderstorm Warning 142, NWS St. Louis, MO

733 
WWUS53 KLSX 081932
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
232 PM CDT Tue Sep 8 2020

ILC013-083-MOC183-081945-
/O.CON.KLSX.SV.W.0142.000000T0000Z-200908T1945Z/
Calhoun IL-Jersey IL-St. Charles MO-
232 PM CDT Tue Sep 8 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM CDT
FOR SOUTHEASTERN CALHOUN...SOUTHWESTERN JERSEY AND NORTHEASTERN ST.
CHARLES COUNTIES...

At 232 PM CDT, a severe thunderstorm was located over Grafton, moving
northeast at 20 mph.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Grafton, Elsah, Portage Des Sioux and Otterville. 

This also includes Pere Marquette State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3890 9051 3899 9055 3909 9042 3893 9033
TIME...MOT...LOC 1932Z 241DEG 16KT 3898 9045 

HAIL...0.88IN
WIND...60MPH
 
$$

MRM

956 
WWUS53 KLSX 081946
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
246 PM CDT Tue Sep 8 2020

ILC013-083-MOC183-081955-
/O.EXP.KLSX.SV.W.0142.000000T0000Z-200908T1945Z/
Calhoun IL-Jersey IL-St. Charles MO-
246 PM CDT Tue Sep 8 2020

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CALHOUN...
SOUTHWESTERN JERSEY AND NORTHEASTERN ST. CHARLES COUNTIES HAS
EXPIRED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire.

LAT...LON 3890 9051 3899 9055 3909 9042 3893 9033
TIME...MOT...LOC 1945Z 241DEG 16KT 3901 9038 

$$

MRM

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1253 PM CDT Tue Sep 8 2020

.SHORT TERM...  (Through Late Wednesday Afternoon)
Issued at 427 AM CDT Tue Sep 8 2020

A strong front extending from PPQ southwest to just north of COU
will move slowly southeastward today and tonight as the
convergence along it gradually weakens tonight. Scattered
convection is expected along and behind the front with the best
coverage this afternoon and this evening as the atmosphere
destabilizes along and south of the front. Most of the
showers/storms today and tonight will be across northeast and
central MO and west central IL, north and west of STL. High
temperatures will be cooler across northeast and central MO and
west central IL behind the cold front due to low level cold air
advection along with low level cloudiness inhibiting diurnal solar
insolation. Only a slight chance of showers is expected on
Wednesday across northeast and central MO and west central IL as
the front weakens and an upper level ridge builds over the OH and
TN Valley regions. Most of the precipitation will be in the Plains
ahead of a slow moving, cut-off upper level low over the Four
Corners region.

GKS

.LONG TERM...  (Wednesday Night through Monday)
Issued at 427 AM CDT Tue Sep 8 2020

A relatively cool and dry weather pattern can be expected on
Thursday and Friday with a large and strong surface ridge moving
eastward through the Northern Plains and Great Lakes region with
mainly northeast winds over our area.  Temperatures will be about
5 to 10 degrees below normal. Upper level ridging will extend
from the TN Valley region northwest into MO. Most of the
precipitation will be west of the forecast area and ahead of a
an upper level low moving slowly northeastward into the Northern
Plains on Friday. Will have scattered showers and a few storms
late Friday night through Saturday evening as the upper level low
opens up and gradually weakens as it moves through the Great Lakes
region and drags a weak cold front southeastward through our
forecast area. Drier and slightly cooler conditions can be
expected for Sunday and Monday as a large and strong surface
ridge centered over the Northern Plains and Great Lakes region
moves through our area.

GKS

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1236 PM CDT Tue Sep 8 2020

Low MVFR and IFR flight conditions will prevail north of a cold
front which is currently stretching from near KCOU to KSPI. This
cold front will drift southward over the next 24 hours and the low
ceilings will drift south along with it to overspread the entire
forecast area by 08-10Z. The low ceilings are expected to lift
slowly through the morning. Additionally, scattered showers and
thunderstorms will affect the area, mainly along and north of I-44
in Missouri, and I-70 in Illinois. A few storms could produce
wind gusts between 40-50kts this afternoon.

SPECIFICS FOR KSTL:

Expect showers and thunderstorms in the vicinity of the terminal
this afternoon. Latest model guidance suggests that the
thunderstorm activity could continue beyond 22Z as forecast in the
TAF. The cold front which is helping to drive these storms is
expected to drift through the terminal this evening, and this will
bring the wind around to the north-northeast and bring the lower
ceilings which are now in northeast Missouri down into the STL
Metro. Low MVFR and IFR flight conditions are likely tonight, and
will probably be slow to improve on Wednesday.

Carney

&&

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

WFO LSX

Hazardous Weather Outlook
National Weather Service Saint Louis MO
831 AM CDT Tue Sep 8 2020

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-091200-
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-
831 AM CDT Tue Sep 8 2020

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

.DAY ONE...Today and tonight.

Thunderstorms are likely today and tonight, mainly along and north of
I-44 in Missouri and I-70 in Illinois. A few strong to severe storms
are possible this afternoon and early evening. The primary threat
from these storms will be damaging winds.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

There is a chance of thunderstorms from Friday afternoon through
Saturday night across parts of the area.

.SPOTTER INFORMATION STATEMENT...

Limited spotter activation may be needed this afternoon and evening.

Carney