Flash Flood and Hail in Missouri, May 25, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1131 AM CDT TUE MAY 25 2010

...MESO-SCALE CONVECTIVE DISCUSSION...

.UPDATE...

THUNDERSTORMS HAD ALREADY DEVELOPED LATE THIS MORNING ACROSS
PORTIONS OF THE MISSOURI OZARKS. CONVECTION HAD FORMED WITHIN AN
AXIS OF DEEP MOISTURE CONVERGENCE ALONG A NORTH TO SOUTH SURFACE BOUNDARY
FROM NORTHEAST TO SOUTHWEST MISSOURI. OROGRAPHIC LIFT ALONG THE
OZARK PLATEAU IS ALSO LIKELY PLAYING A ROLE. MIXED LAYER CAPE WAS
NEAR 1500 J/KG BUT THERE WAS VERY LITTLE IF ANY SHEAR. ENVIRONMENT
WILL BE FAVORABLE FOR THE CONTINUED DEVELOPMENT OF PULSE TYPE
THUNDERSTORMS THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THERE
IS A LIMITED RISK FOR MARGINALLY SEVERE STORMS WITH LOCALIZED
DAMAGING WINDS AND HAIL. LOCALIZED FLOODING CANNOT BE RULED OUT GIVEN
THE SLOW MOVEMENT OF THE STORMS AND PRECIPITABLE WATER VALUES NEAR
1.5 INCHES. FORECAST GRIDS HAVE BEEN UPDATED TO REFLECT HIGHER
PRECIPITATION CHANCES OVER PORTIONS OF THE MISSOURI OZARKS.

FOSTER

&&

.DISCUSSION...

AFTER SOME SCATTERED CONVECTION...MOSTLY EAST OF
KSGF LATE YESTERDAY...QUIET WEATHER WAS OBSERVED OVERNIGHT. MAIN
CONCERN WILL BE DIURNALLY DRIVEN CONVECTION OVER THE 2-3 DAYS.

AN UPPER RIDGE (500MB) REMAINS IN PLACE OVER THE REGION ATTM.
YESTERDAY A WEAK DISTURBANCE MOVED SOUTHWEST FROM SOUTHERN
IL/WESTERN KY INTO SE MO TO HELP COOL MID LEVELS AND INITIATE
CONVECTION WHICH AFFECTED THE EASTERN CWFA. FOR TODAY...ANY SUBTLE
FEATURES ARE HARD TO LOCATE...BUT IN GENERAL PROGS CONTINUE THE
TREND OF GRADUALLY COOLING THE 800-600MB LAYER RESULTING IN DECENT
MIXED LAYER CAPE BY LATE MORNING AND THIS AFTERNOON...ON THE ORDER
OF 2000 J/KG (FROM GFS BUFR) DEPENDING ON HOW YOU ADJUST LOW LEVEL
MOISTURE PROFILES. SATELLITE DERIVED SOUNDINGS OVER THE EASTERN
CWFA ARE SHOWING THIS TREND. LEFT OVER CONVECTIVE BOUNDARIES ARE
IN PLACE...SO SEE NO REASON TO MAKE MANY CHANGES TO OUR PULSE TYPE
DIURNAL TSTM FORECAST SCENARIO FOR TODAY...OR FOR WED FOR THAT
MATTER. IN THEORY...INSTABILITY/PWATS SHOULD ACTUALLY BE A LITTLE
STRONGER/HIGHER WED.

FOR THU/FRI...THE UPPER RIDGE RETROGRADES BACK OVER THE CNTRL
PLAINS WITH SFC HIGH PRESSURE GRADUALLY NOSING ITS WAY SOUTH INTO
THE UPPER MIDWEST. BY FRI...SOME LOWER LEVEL DRIER AIR ADVECTS
SOUTH INTO MO REDUCING THE OVERALL CHANCES FOR CONVECTION...BUT
SOME MOISTURE WILL LINGER OVER FAR SOUTHERN MO. WILL KEEP POPS IN
FOR THU AND BUT RESTRICT REDUCED TSTM CHANCES TO FAR SOUTHERN MO FOR
FRI.

SAT...THE UPPER RIDGE SHIFTS BACK TO THE EAST AS STRONG UPPER
SYSTEM MOVES FROM THE EAST PAC INTO THE WEST COAST AND EVENTUALLY
THE NORTHERN AND CNTRL ROCKIES BY LATE SAT/SUNDAY. MID LEVEL/700MB
TEMPERATURES ARE EXPECTED TO WARM ONCE AGAIN CAPPING OFF
SIGNIFICANT CONVECTION.

SUNDAY AND BEYOND....A LARGE SCALE PATTERN CHANGE BY EARLY NEXT
WEEK MAY LEAD TO A MORE ACTIVE PATTERN FOR RAIN/TSTM WITH THE GFS
AND ECMWF CONSISTENTLY SIGNALING A BREAK DOWN OF THE UPPER RIDGE
THAT HAS PERSISTED OVER THE REGION. THE GFS IS A LITTLE FASTER IN
MOVING A SHORTWAVE INTO THE PLAINS SUNDAY WHILE THE ECMWF HOLDS
OFF ON THIS BY ABOUT 12-24 HOURS LATER. OVERALL PROBABLY PREFER
THE ECMWF GIVEN THE STRENGTH OF THE RIDGE. THIS COULD BRING A
CHANCE OF PRECIP BY SUNDAY NIGHT. DAY SHIFT WILL LOOK AT THIS PART
OF THE FORECAST FOR THE NEXT FORECAST PACKAGE. DSA

&&

.AVIATION...

FOR THE 12Z TAFS...AN UPPER LEVEL RIDGE AND SURFACE HIGH PRESSURE
REMAINS IN PLACE ACROSS THE REGION AND WILL CONTINUE TO CONTROL
FLIGHT WEATHER CONDITIONS FOR THE AREA. WITH THE WARM AND HUMID
CONDITIONS EXPECTED DURING THE AFTERNOON HOURS...SUMMER LIKE
AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. OTHERWISE
EXPECT VFR CONDITIONS TO PREVAIL.

HATCH

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SPRINGFIELD MO
811 AM CDT TUE MAY 25 2010

KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-261315-
BOURBON-CRAWFORD-CHEROKEE-BENTON-MORGAN-MILLER-MARIES-VERNON-
ST. CLAIR-HICKORY-CAMDEN-PULASKI-PHELPS-BARTON-CEDAR-POLK-DALLAS-
LACLEDE-TEXAS-DENT-JASPER-DADE-GREENE-WEBSTER-WRIGHT-NEWTON-
LAWRENCE-CHRISTIAN-DOUGLAS-HOWELL-SHANNON-MCDONALD-BARRY-STONE-
TANEY-OZARK-OREGON-
811 AM CDT TUE MAY 25 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE MISSOURI
OZARKS AND EXTREME SOUTHEAST KANSAS.

.DAY ONE...TODAY AND TONIGHT.

THE HAZARDOUS WEATHER RISK LEVEL IS...LIMITED.

WEATHER HAZARDS EXPECTED:

THE THUNDERSTORM WIND GUST RISK IS LIMITED WITH GUSTS OF 60 MPH
POSSIBLE.
THE LIGHTNING RISK IS LIMITED.

AREAS AFFECTED AND TIMING:

SCATTERED THUNDERSTORMS ARE EXPECTED TO BEGIN TO DEVELOP OVER THE
REGION AFTER 11 AM AS DAYTIME INSTABILITY INCREASES. A FEW STORMS
WILL BE CAPABLE OF STRONG TO SEVERE WIND GUSTS AND SMALL HAIL.
THUNDERSTORM ACTIVITY IS EXPECTED GRADUALLY DECREASE DURING THE
EVENING HOURS AFTER SUNSET.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

SCATTERED THUNDERSTORMS ARE EXPECTED MAINLY DURING THE AFTERNOON
AND EARLY EVENING WEDNESDAY AND THURSDAY. A FEW OF THE STRONGER
STORMS COULD BECOME SEVERE...WITH A LIMITED RISK FOR DAMAGING
WINDS IN EXCESS OF 60 MPH. SMALL HAIL WILL ALSO BE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

  SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

&&

THIS PRODUCT IS NOW AVAILABLE IN GRAPHICAL FORMAT...ALONG WITH
OTHER WEATHER...HYDROLOGICAL AND CLIMATE INFORMATION...AT
HTTP://WWW.CRH.NOAA.GOV/SGF(ALL LOWERCASE)

KARDELL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1152 AM CDT TUE MAY 25 2010

MOZ079-251715-
POLK MO-
1152 AM CDT TUE MAY 25 2010

...SIGNIFICANT WEATHER ALERT FOR CENTRAL POLK COUNTY UNTIL 1215 PM
CDT...

AT 1151 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 4 MILES SOUTHEAST OF BOLIVAR. THIS STORM WAS
NEARLY STATIONARY. PENNY SIZE HAIL...AND WINDS AROUND 50 MPH ARE
EXPECTED WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE BOLIVAR...HALF WAY AND MORRISVILLE.

KARDELL