Tornado and Flash Flooding in Missouri, July 16, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
910 PM CDT THU JUL 15 2004

.DISCUSSION...

EARLY EVENING SATELLITE IMAGERY AND OBJECTIVE ANALYSIS INDICATE MID
LEVEL RIDGE CENTERED OVER CENTRAL ROCKIES WITH 100+KT 250MB JET
STREAK EMBEDDED WITHIN NORTHWEST FLOW ALOFT ACROSS UPPER/MID MS
VALLEY. SURFACE ANALYSIS INDICATES COLD FRONT STRETCHING FROM
EASTERN DAKOTAS BACK INTO WESTERN NEBRASKA...WHILE SURFACE RIDGE IN
PLACE ACROSS EASTERN IA/MO. AHEAD OF SURFACE FRONT MOISTURE AXIS
WITH LOW TO MID 70 DEW POINTS IN PLACE ACROSS EASTERN
KS/NE...RESULTING IN AXIS OF >3000 J/KG 100MB MLCAPE...WHILE FURTHER
EAST TIGHT INSTABILITY AXIS EXTENDS ACROSS WESTERN MO WHERE DEW
POINTS FALL INTO THE LOWER TO MID 60S ACROSS CENTRAL/EASTERN MO
ASSOCIATED WITH SURFACE RIDGE. TOP/OAX SOUNDINGS INDICATE FAIRLY
SUBSTANTIAL CAPPING INVERSION REMAINS IN PLACE ACROSS THE REGION.
SEVERE CONVECTION EARLIER THIS EVENING ACROSS SOUTHEAST SD/NORTHEAST
NE WEAKENED RAPIDLY AS IT MOVED INTO EAST CENTRAL NE WHERE STRONGER
CAP WAS IN PLACE...AND SCATTERED ELEVATED CONVECTION FURTHER EAST
ACROSS IA REMAINS WEAK.

ALTHOUGH CAPPING INVERSION REMAINS STRONG THIS EVENING...IT STILL
APPEARS FORCING LATER TONIGHT WILL ALLOW FOR AT LEAST SCATTERED
CONVECTION TO DEVELOP. AS JET STREAK PROPAGATES SOUTHWARD OVERNIGHT
AND 850MB FLOW VEERS...EXPECT REGION OF ENHANCED LIFT TO SPREAD
ACROSS WESTERN HALF OF FORECAST AREA...ASSOCIATED WITH COMBINATION
OF RIGHT ENTRANCE REGION OF PASSING JET STREAK...AND 850MB THETA-E
ADVECTION. THIS MAY BE SUFFICIENT TO WEAKEN CAP AND ALLOW PARCELS TO
REACH LFC...ALLOWING FOR CONVECTION TO DEVELOP AND POSSIBLY BECOME
WIDESPREAD ACROSS EASTERN KS/WESTERN MO AFTER 06Z. DEEP LAYER SHEAR
IN EXCESS OF 40 KTS SUGGESTS STORMS HAVE POTENTIAL TO BECOME
SEVERE...WITH DAMAGING WINDS THE MAIN THREAT. HIGH FREEZING/WET-BULB
ZERO LEVELS WILL LIKELY KEEP HAIL THREAT MARGINAL AT BEST. GOING
FORECAST LOOKS IN GOOD SHAPE AND HAVE ONLY MADE MINOR ADJUSTMENTS.

SEAMAN

.PREV DISCUSSION...

315 PM...
MAIN FORECAST CONCERN RELATES TO CONVECTIVE COMPLEX LATE THIS
EVENING.

CONVECTIVE CLUSTER THAT FORMED OVER THE SOUTHEAST CORNER OF
SOUTH DAKOTA AND NORTHEAST NEBRASKA WITHIN THE THETA/E RIDGE HAS
TAKEN A DIVE SOUTH AND WEAKENED CONSIDERABLY OVER THE PAST 1 TO 2
HOURS. A FEW WANING LEFTOVER SHOWERS WILL MAKE THEIR WAY INTO
NORTHWEST MISSOURI AND NORTHEAST KANSAS THROUGH THE EARLY EVENING.

12Z ETA AND GFS MODELS HAVE COME INTO GOOD AGREEMENT FOR
TONIGHT...GIVING A BIT MORE CONFIDENCE TO THE STORM SCENARIO. A NEW
ROUND OF CONVECTION IS TO DEVELOP THIS EVENING WITHIN THE
INSTABILITY AXIS AS THE SURFACE TROUGH PUSHES INTO SOUTHEAST SOUTH
DAKOTA AND EASTERN NEBRASKA. THIS AREA OF CONVECTION SHOULD ORGANIZE
INTO AN MCS AND PROPAGATE SOUTH/SOUTHEAST. STORM MOVEMENT WILL BE
RATHER FAST...WITH STRONG NORTHWEST FLOW OF 35 TO 40 KNOTS AT 500MB.
CURRENT THINKING IS THAT STORMS WILL BE STRONG TO SEVERE WITHIN
RELATIVELY NARROW BAND OF STRONG 850MB THETA E ADVECTION/ISENTROPIC
LIFT ABOUT 100 MILES WIDE POSITIONED NEAR THE KANSAS/MISSOURI
BORDER. THE STORMS ARE EXPECTED TO ENTER THE NORTHWEST PORTION OF
THE FORECAST AREA AROUND 10 PM...AND MOVE OUT OF THE SOUTHERN
FORECAST AREA JUST AFTER DAYBREAK. THE SEVERE THREAT LOOKS TO BE
HAIL AND DAMAGING WINDS THIS EVENING...AND BECOME PREDOMINANTLY A
DAMAGING WIND THREAT DURING THE OVERNIGHT HOURS.

AFTER THE STORM COMPLEX PUSHES OUT OF THE FORECAST AREA TOMORROW
MORNING...THE POSSIBILITY OF REDEVELOPMENT IS IN QUESTION FOR THE
AFTERNOON. HAVE GONE WITH ONLY LOW END PRECIPITATION CHANCES
CONFINED TO THE SOUTHERN TIER OF COUNTIES AS OUTFLOW BOUNDARY/IES
SHOULD END UP IN SOUTHERN MISSOURI...BUT WILL HAVE TO WAIT TO SEE
HOW THE SYSTEM PANS OUT TONIGHT. TEMPERATURES TOMORROW WILL HIGHLY
DEPEND UPON CLOUD COVER OR CLEARING THEREOF. KEPT GOING TEMPERATURES
OF MID TO UPPER 80S. NORTHERLY BOUNDARY LAYER WINDS WILL KEEP
TEMPERATURES FROM GETTING OUT OF HAND OVER THE WEEKEND...WITH
DAYTIME READINGS EXPECTED IN THE 80S.

ECMWF AND UKMET MODEL SOLUTIONS ARE IN VERY GOOD AGREEMENT FOR NEXT
WEEK IN TERMS OF THE UPPER LEVEL PATTERN...WITH THE GFS NOT FAR
BEHIND. EARLY NEXT WEEK THE UPPER LOW ACROSS THE EASTERN CONUS
PULLS AWAY TOWARD THE ATLANTIC COAST...AND A FAST ZONAL FLOW SETS UP
ACROSS THE NORTHERN TIER CONUS WITH HIGH PRESSURE STILL CENTERED
OVER THE DESERT SOUTHWEST. TEMPERATURES WILL RESPOND WITH A WARMING
TREND ON MONDAY THROUGH MID WEEK. A COLD FRONT IS THEN EXPECTED TO
MOVE ACROSS THE AREA LATE WEDNESDAY INTO THURSDAY.

STOFLET

&&

.PREV DISCUSSION...

224 AM THU...
CLEAR SKIES TONIGHT ACROSS THE FORECAST AREA. SOME CLOUDS WILL BE
COMING IN FROM THE NORTHWEST ASSOCIATED WITH DYING COMPLEX IN SODAK
AND THE ONE IN NODAK. ALSO SEEING A FEW CLOUDS DEVELOP IN THETA/E
ADV AREA IN EASTERN KS/WESTERN MO.  WILL HAVE TO KEEP AN EYE ON THIS
AREA IN CASE SOME ELEVATED CONVECTION GETS GOING AROUND SUNRISE...
BUT SO FAR LOOKS LIKE ITS NOT GOING TO.

FOR TODAY...SURFACE RIDGE EXITS AREA. UNLESS SOME CLOUD COVER
HINDERS...TEMPS SHOULD BE IN THE UPPER 80S ACROSS ALL BUT NORTHEAST
MO WITH MID 80S.  TONIGHT THERE IS A DECENT CHANCE THAT THE AREA
WILL SEE CONVECTION AHEAD OF A COLD FRONT MOVING IN FROM THE
NORTHWEST. THE BEST INSTABILITY IS JUST TO OUR WEST IN EASTERN
KANSAS...WHICH SHOULD KEEP ANY SEVERE WEATHER CONFINED TO OUR
WESTERNMOST COUNTIES.  MODELS HAVE SOME DISCREPANCIES WITH HOW FAST
THE FRONT WILL MOVE THROUGH...AFFECTING WHEN TO END THE RAIN
CHANCES.  HAVE KEPT THEM IN THE MORNING...BUT EXPECT CONVECTION TO
MOVE THROUGH RATHER QUICKLY AND BE DRY IN THE AFTERNOON.  THIS IS
MORE LIKE THE ETA/S DEPICTION. HAVE KEPT SOME TOKEN LOW AFTERNOON
CHANCES IN SOUTHERN CWA JUST IN CASE.  H8 TEMPS COOL INTO THE 15C
RANGE BY SATURDAY...SO HAVE DROPPED TEMPS INTO A MID 80S MEDIAN.
THE RIDGE BACKS UP OVER THE WEEKEND...SO AM STILL ATTEMPTING TO KEEP
CONDITIONS DRY WITH A WARMING TREND BACK INTO THE UPPER 80S BY
MONDAY.  NO CHANGES MADE TO THE EXTENDED.

27

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.

WFO EAX

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE KANSAS CITY-PLEASANT HILL MO
1241 PM CDT THU JUL 15 2004

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-161100-

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST...NORTH CENTRAL AND
WEST CENTRAL MISSOURI...AS WELL AS EXTREME EASTERN KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED SEVERE THUNDERSTORMS ARE POSSIBLE TONIGHT ACROSS THE
WESTERN PORTION OF THE OUTLOOK AREA...MAINLY WEST OF A LINE FROM
BETHANY TO CARROLLTON TO SEDALIA. THUNDERSTORMS ARE EXPECTED TO
DEVELOP IN EASTERN NEBRASKA THIS EVENING AND MOVE INTO EXTREME
NORTHWEST MISSOURI AND EXTREME NORTHEAST KANSAS AROUND MIDNIGHT. THE
STORMS WILL MOVE SOUTHEAST THROUGH THE NIGHT...POSSIBLY REACHING THE
MOUND CITY KANSAS...CLINTON AND SEDALIA AREAS NEAR DAYBREAK. THE
PRIMARY THREATS ARE LARGE HAIL AND DAMAGING WINDS WITH THE GREATEST
THREAT ALONG THE KANSAS AND MISSOURI BORDER.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THE THURSDAY NIGHT THUNDERSTORMS MAY LINGER INTO THE MID-MORNING
HOURS ON FRIDAY ACROSS THE SOUTHERN PORTION OF THE OUTLOOK
AREA...MAINLY SOUTH OF A LINE FROM PAOLA TO WARRENSBURG TO SEDALIA.
THESE STORMS MAY ALSO BE SEVERE WITH THE LARGE HAIL AND DAMAGING
WINDS THE PRIMARY THREATS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND EARLY FRIDAY WEST OF A
LINE FROM BETHANY TO CARROLLTON TO SEDALIA.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC AND CLIMATE
INFORMATION...IS AVAILABLE ON THE WEB AT (LOWER CASE)
HTTP://WWW.CRH.NOAA.GOV/EAX OR HTTP://WEATHER.GOV.

DB