River Flood Warning 40, NWS St. Louis, MO

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
634 AM CDT Wed Jun 10 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 238 AM CDT Wed Jun 10 2015

A few isolated SH/TS could still develop early this morning across
the northwestern CWA due to moisture convergence, but any precip
which develops should dissipate during the mid to late morning
hours.

A cold front will sag southward today, reaching central IA or
perhaps as far south as the MO/IA border. Conditions should be
quite toasty south of the front, which includes the LSX CWA. Highs
in the low to mid 90s (mid/upper 90s in the urban core of St.
Louis) will be around 10-15 degrees above average for this time of
year.

The best chance for isolated to scattered thunderstorms appears to
be across the northern CWA during the late afternoon and early
evening hours. This is the area where higher dew points (due to
moisture pooling along the front) will lead to greater
instability, and late afternoon/early evening is the time when
H7-H5 lapse rates will be steepest (6-6.5 deg C/km) in this area.
The sagging front also serves as a focusing mechanism, and the
front will be close to the northern CWA by late afternoon.

Recent model forecasts of AOB 10 kts of 0-6 km shear are even
lower than forecasts from 24 hrs ago, although the high values of
instability may compensate for the lack of shear to support a few
strong to severe pulse-type storms this afternoon, especially
across the northern CWA.

Kanofsky

.LONG TERM:  (Tonight through Tuesday)
Issued at 238 AM CDT Wed Jun 10 2015

The upper flow continues to transition tonight, then remains
southwesterly or quasizonal for the rest of the forecast period. A
lee surface low will have developed in KS by 00z tonight in
response to an approaching disturbance. The surface low rides
northeastward along the boundary tomorrow, lifting the stalled
front northward as a warm front and leaving a trailing cold front
in its wake. Warm and unstable conditions will still exist south
of the warm frontal boundary tomorrow, so highs in the 90s with
isolated to scattered thunderstorms (especially across the
northern CWA) still looks like a reasonable forecast.

Recent model runs now bring the trailing cold front as far south
as central MO on Thu night into Fri. This boundary lingers across
the region through Friday night/Saturday, providing a focus for
SH/TS across most of the CWA through the weekend given the
presence of several passing vorticity maxima within southwest flow
aloft.

Kanofsky

&&

.AVIATION:  (For the 12z TAFs through 12z Thursday Morning)
Issued at 629 AM CDT Wed Jun 10 2015

A few showers moving into northeast MO and west central IL could
briefly impact KUIN this morning with a brief period of very light
rain or sprinkles. A cold front will stall along the MO/IA border
later today and thunderstorms are expected to develop along it
late this afternoon and evening. Some of these storms could also
impact KUIN and thus added a PROB30 group for this evening.
Elsewhere VFR flight conditions will prevail with southwest
surface winds.

Specifics for KSTL:

VFR flight conditions will prevail with southwest surface winds.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
353 AM CDT WED JUN 10 2015

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-110000-
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-ST. 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-ST. CHARLES MO-FRANKLIN MO-
ST. LOUIS MO-ST. LOUIS CITY MO-JEFFERSON MO-CRAWFORD MO-
WASHINGTON MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-IRON MO-
MADISON MO-REYNOLDS MO-
353 AM CDT WED JUN 10 2015

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 POSSIBLE TODAY ACROSS NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS. A FEW OF THE STRONGER STORMS DURING THE
AFTERNOON COULD PRODUCE HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS ARE POSSIBLE ACROSS NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS ON THURSDAY AND THURSDAY NIGHT. THUNDERSTORM
CHANCES THEN SPREAD ACROSS THE ENTIRE AREA FROM FRIDAY THROUGH
TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT.

KANOFSKY