Special Weather Statement, NWS St. Louis, MO

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1045 PM CDT Mon Jun 11 2018

.UPDATE...
Issued at 835 PM CDT Mon Jun 11 2018

Two ongoing clusters of storms of note this evening.

The first is of more immediate concern as it is affecting our
forecast area in southern IL. This cluster initially developed as
discrete cells near an old frontal boundary and later congealed
into a small MCS that we see now. It is expected to exit around
02z and has already produced a flash flood and multiple severe
threats (hail, wind, possible tornado) along its path. The
remainder of the frontal boundary and outflows kicked out from
this MCS have been quite inactive and the door for them to become
active appears to be rapidly shutting. It looks like most of the
forecast area will be dry for the remainder of this evening.

The second area is a much larger severe weather producing MCS in
southwest IA, northwest MO, and northeast KS. The main thrust of
this MCS and its severe threat should be almost due south, but
CAMs have been consistent in bringing a more northerly component
into our forecast area from the northwest after midnight. It
should be in a weakening stage and may be accompanied by some
gusty non-severe winds and it is hard to determine how well it
will hold up as it tracks east to southeast late tonight. Have
maintained a chance with the highest PoPs in the western and
northwestern CWA.

Min temps overnight will be in the upper 60s to mid 70s.

Otherwise, a weak cold front will track thru the forecast area on
Tuesday and may kick off some afternoon convection for areas
mainly south and east of Saint Louis. Max temps Tuesday will only
be slightly less than persistence with upper 80s and lower 90s.

TES

&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 249 PM CDT Mon Jun 11 2018

Concerns through the Tuesday afternoon will pertain to the
thunderstorms potential this afternoon, then again during the day
Tuesday.

Current analysis depicts a nearly stationary boundary stretching
from near the IA/MO border eastward through IL/IN region. This
originated a bit further south early this morning, before
meandering northward this afternoon. This is likely to become the
focus for initial convection early this afternoon and into the
evening, where moisture convergence is maximized and instability
gradients reside. Expecting a narrow corridor more focused
development.

Given precipitable water values in excess of 1.5 inches through
the region, along with relatively weak flow, locally heavy rain
with localized ponding is a concern. However, confidence is low
that similar areas affected by yesterday's training rainfall will
be impacted again today. Best potential remains a bit further
north into central IL, where highest rainfall totals were
received. Therefore, held off on any watch products at this time
and will keep an eye on this evening's development.

Further south of the this boundary, sct/isolated convection is
possible and will be more diurnally driven. Expect activity to be
shorter lived and wane after sunset. Good instability with
MUCAPEs around 3k J/kg or better may give rise to a strong storm
with any severe potential being isolated.

Well-organized convection is expected to remain well west of the
forecast area through western MO, originating along a cold front
in the central plains. There is the potential for an MCS to
materialize and dive almost due south. The northern extent of the
line may reach central Missouri late tonight, but given better
support to the west, expecting this to weaken as it spreads out to
the east.

The cold front pushes into the bi-state area during the day
Tuesday. Pending convection may impact tomorrow's thunderstorms
with any residual cloud cover. Front should be positioned through
eastern Missouri by early afternoon with better potential for
development east of the Mississippi River Tuesday afternoon.

Maples

.LONG TERM...  (Tuesday Night through Next Monday)
Issued at 249 PM CDT Mon Jun 11 2018

Tuesday's frontal boundary will continue to slowly slip south and
east through Wednesday. Scattered showers and thunderstorms are
possible along and ahead of the front. As is common for this time
of year, forward progression of the front could slow or stall.
Expect southern sections of Missouri and Illinois to have a better
potential from afternoon storms before the boundary clears the
area.

Surface high pressure builds in through the middle of the week and
will effectively limit rain potential. An upper ridge is still
well-advertised to develop from the mid to late week period. This
is likely to keep the main storm track outside the area. Main
story late this week into the weekend will be the building heat
with temperatures that may climb well into the 90s.

Maples

&&

.AVIATION...  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1045 PM CDT Mon Jun 11 2018

VFR conditions, outside of thunderstorms, will prevail at the TAF
sites thru the valid period. MCS rolling thru northwest MO will
kick off a weakening component that should affect near COU and UIN
but very uncertain on surviving to STL metro sites and will
continue to hold off on mention with better chance ahead of weak
cold front during peak heating Tuesday afternoon. Otherwise, look
for light south winds to gradually veer thru the valid period to
NW behind the front.

TES

&&

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

WFO LSX

Hazardous Weather Outlook
National Weather Service Saint Louis MO
1047 PM CDT Mon Jun 11 2018

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-121200-
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair IL-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
1047 PM CDT Mon Jun 11 2018

This hazardous weather outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Tonight

The chance for thunderstorms continues overnight. Isolated strong
storms are possible with gusty winds in portions of central and
northeast Missouri.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

The chance for thunderstorms will continue for parts of the
forecast area until Friday.

Isolated strong to severe storms are possible Tuesday and Tuesday
evening across southeast Missouri and southwest Illinois. The
primary threats are large hail and damaging wind gusts.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated tonight.

TES

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
816 PM CDT MON JUN 11 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0815 PM     TSTM WND GST     1 NW SALEM              38.65N 88.97W
06/11/2018  E48 MPH          MARION             IL   AWOS

&&

TILLY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
851 PM CDT MON JUN 11 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0825 PM     TSTM WND DMG     2 S TONTI               38.64N 88.98W
06/11/2018                   MARION             IL   TRAINED SPOTTER

            SPOTTER REPORTED 4 TO 16 INCH TREE LIMBS
            DOWN. TIME ESTIMATED FROM RADAR.

&&

AE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
858 PM CDT MON JUN 11 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0815 PM     FLASH FLOOD      3 S PATOKA              38.72N 89.10W
06/11/2018                   MARION             IL   CO-OP OBSERVER

            HIGHWAY 51 CLOSED DUE TO WATER OVER THE
            ROAD. TIME OF CLOSURE ESTIMATED.

&&

TILLY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
912 PM CDT MON JUN 11 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0850 PM     HEAVY RAIN       1 S IUKA                38.60N 88.79W
06/11/2018  E2.30 INCH       MARION             IL   TRAINED SPOTTER

&&

TILLY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
1020 PM CDT MON JUN 11 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0805 PM     TSTM WND DMG     ODIN                    38.62N 89.05W
06/11/2018                   MARION             IL   PUBLIC

            TREE DAMAGE. TYPE AND SIZE UNKNOWN.

&&

TES

Special Weather Statement
National Weather Service St Louis MO
1239 AM CDT TUE JUN 12 2018

MOZ018-019-026-034-041-042-047-048-050-120645-
Moniteau MO-Audrain MO-Monroe MO-Cole MO-Knox MO-Boone MO-
Callaway MO-Lewis MO-Shelby MO-
1239 AM CDT TUE JUN 12 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN COLE...KNOX...
BOONE...WESTERN AUDRAIN...SHELBY...NORTHWESTERN CALLAWAY...
SOUTHWESTERN LEWIS...MONROE AND MONITEAU COUNTIES UNTIL 145 AM CDT...

At 1238 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Edina to near Sturgeon to near Cole Camp.
Movement was southeast at 35 mph.

Half inch hail and wind gusts of 50 to 55 mph will be possible with
these storms.

Locations impacted include...
Columbia, Jefferson City, Fulton, Mexico, California, Centralia,
Ashland, Tipton, Holts Summit, Shelbina, Paris, Edina, Columbia
Regional Airport, Hallsville, St. Martins, Auxvasse, Sturgeon,
Clarence, Russellville and New Bloomfield.

This includes Interstate 70 in Missouri between exits 115 and 148.

This also includes  Rock Bridge State Park, Finger Lakes State Park,
Union Covered Bridge Historic Site, and Jewell Cemetery Historic
Site.

LAT...LON 3868 9262 3892 9250 3898 9257 3914 9249
      3925 9242 3924 9231 3995 9229 3996 9234
      4021 9235 4012 9184 3886 9185 3843 9241
      3843 9262 3860 9284 3868 9284
TIME...MOT...LOC 0538Z 313DEG 33KT 4012 9224 3921 9226 3851 9317

GKS