Severe Thunderstorm Warning 146, NWS Kansas City, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
350 AM CDT SUN JUL 11 2004

.DISCUSSION...

350 AM...
WEATHER OVER NEXT 24 HOURS ABOUT AS CLEAR AS MUD. ETA/GFS QPF AND
MASS FIELDS HAVE CONTINUED TO SHOW TOO MUCH RAIN/CLOUD COVERAGE AND
FURTHER OUT SUFFER FROM CONVECTIVE FEEDBACK PROBLEMS. ANTICYCLONE
PROGGED TO BUILD INTO THE CENTRAL PLAINS THROUGH TUESDAY AND BRING
THE HOTTEST TEMPERATURES OF THE YEAR. IF MCI REACHES 90F TODAY IT
WILL BE THE FIRST TIME THIS YEAR AND THE SECOND LATEST DATE TO REACH
90F.

CONVECTIVE COMPLEX ALONG THE IA/NE BORDER BEING SUPPORTED BY VEERING
SOUTHERLY LOW LEVEL JET AND MESOSCALE VORTICITY CENTER. THIS
CONVECTION SHOULD REMAIN IN IA. WITH A WEAK NORTHWEST-SOUTHEAST
BOUNDARY CUTTING ACROSS NORTHERN PORTION OF CWA THERE REMAINS A
CHANCE FOR SHOWERS AND THUNDERSTORMS TO FORM ALONG THIS BOUNDARY IN
THE STILL UNCAPPED ENVIRONMENT. HAVE ADDED SLIGHT CHANCE POPS TO
REST OF FORECAST AREA FOR AFTERNOON AIRMASS TYPE ISOLATED CONVECTION.

AS MID LEVEL HEIGHTS INCREASE ACROSS THE CENTRAL U.S. ON MONDAY AND
TUESDAY THE 700MB TEMPERATURES WARM SUFFICIENTLY TO EFFECTIVELY CAP
ANY CONVECTION OVER CWA THROUGH TUESDAY. ETA/GFS/CANADIAN MODELS
INSIST A STRONG SHORTWAVE WILL DROP SOUTHEAST OUT OF SOUTH CENTRAL
CANADA ON TUESDAY. AS MID LEVEL HEIGHTS LOWER ACROSS EASTERN U.S.
THE UPPER RIDGE WILL RETROGRADE TO THE ROCKIES...THEREBY SETTING UP
A NORTHWEST FLOW REGIME FOR AT LEAST WEDNESDAY AND THURSDAY. THE
RESULTING SURFACE REFLECTION WILL LIKELY BE A BACKDOOR COLDFRONT
WHICH COULD MOVE THROUGH THE CWA TUESDAY NIGHT. HAVE ADDED MENTION
OF SHOWERS AND THUNDERSTORMS TO COVER THIS.

BETWEEN TODAY AND TUESDAY NIGHT HOT AND HUMID WEATHER WILL BE THE
RULE WITH MID 90S COMMONPLACE WITH HEAT INDICES THREATENING HEAT
ADVISORY CRITERIA. WILL HIGHLIGHT THIS INFORMATION IN THE HWO.

COOLER/LESS HUMID AIR WILL MOVE INTO THE REGION FOR WEDNESDAY AND
THURSDAY WITH PASSAGE OF COLD FRONT.

MJ

&&

.PREVIOUS DISCUSSION...

1127 PM...
WITH WEAK SURFACE BOUNDARY RUNNING NORTHWEST TO SOUTHEAST ACROSS
FORECAST AREAS...OUTFLOWS FROM EVENING CONVECTION ALSO IN THE
MIX...AND WATCHING INCREASING AC ON SATELLITE IN NORTHEAST
KANSAS...WILL EXPAND POPS OVERNIGHT TO MOST OF CWA EXPECT EXTREME
NORTHEAST AND SOUTHWEST CORNERS.

PC

&&

.PREV DISCUSSION...

1013 PM...
WILL SCALE BACK START OF FLOOD WATCH UNTIL VERY LATE TONIGHT.
CONFIDENCE IS PRETTY LOW AT THIS POINT THAT AREA WILL SEE HEAVY
ENOUGH RAIN TO ACTUALLY PRODUCE FLASH FLOODING BUT RATHER NOT LOWER
WATCH AT THIS POINT UNTIL HAVE A CHANCE TO ANALYZE ALL THE NEW MODEL
RUNS...SO WILL LEAVE IT TO MIDNIGHT CREW TO DECIDE ITS FATE.

REGARDING CURRENT STORMS...KEEP HAVE REGENERATION WITH OUTFLOW FROM
COLLAPSING STORMS...SO EVEN THOUGH WE ARE PAST SUNSET...WITH STILL
LITTLE CAP IN PLACE...WILL CONTINUE TO HAVE TO DEAL WITH MARGINAL
EVENTS FOR A LITTLE WHILE LONGER.

PC

325 PM...
ACROSS THE NATION TODAY...A BROAD RIDGE REMAINS THE DOMINATE FEATURE
ACROSS THE CENTRAL MIDWEST. THE SHORTWAVE THAT SPARKED THE OVERNIGHT
CONVECTION IN NEBRASKA IS PUSHING INTO IOWA THIS AFTERNOON...WHILE
ANOTHER LITTLE SHORT WAVE...THAT WILL FOCUS TONIGHTS WEATHER...CAN
BE SEEN MOVING EAST THROUGH WYOMING. OTHERWISE A SURFACE
BOUNDARY...THAT WAS ALONG HIGHWAY 36 THIS MORNING...HAS LIFTED INTO
EXTREME SOUTHERN IOWA.

MCS IS EXPECTED TO DEVELOP OVER WESTERN NEBRASKA TONIGHT. CORFIDI
VECTORS AND 1000-500MB THICKNESS FIELD SUGGESTS SYSTEM WILL
BASICALLY MOVE EAST...DEVELOPING SOUTH/SOUTHEAST DOWN THE THETA-E
RIDGE AND LOW LEVEL JET AXIS. MODELS PROG THE JET AXIS TO VEER
OVERNIGHT...WITH CORFIDI VECTORS WEAKENING. EXPECT MCS TO REALLY
SLOW DOWN ON THE SOUTH SIDE...WITH SOME BACK-BUILDING BY THE TIME IT
GETS NEAR THE FORECAST AREA. PRECIPITABLE WATER VALUES ARE PROGGED
AROUND 1.5 INCHES. HPC AND MODEL QPF IS REAL CLOSE TO FLASH FLOOD
GUIDANCE. HAVE OPTED TO ISSUE A FLOOD WATCH FOR EXTREME NORTHWEST
MISSOURI FOR THE MIDNIGHT TO 11 AM TIME FRAME. THIS MATCHES UP WELL
WITH SURROUNDING OFFICES. EXPECT PRECIP TO GRADUALLY WEAKEN AS IT
MOVES EAST SUNDAY MORNING...WITH BRUNT OF THE MCS NORTH OF THE
FORECAST AREA BY THAT TIME.

FOR SUNDAY...THE CLOUD COVER LEFT OVER FROM MCS EXPECTED OVERNIGHT
SHOULD MODERATE TEMPS ALONG THE MISSOURI/IOWA BORDER A LITTLE...BUT
FOR LOCATIONS FARTHER SOUTH LOW 90S WILL BE ON TAP. MONDAY LOOKS TO
BE OUR HOTTEST DAY FOR THE FORESEEABLE FUTURE. TEMPERATURES IN THE
LOWER TO MID 90S IN COMBINATION WITH DEW POINTS RANGING AROUND 70
WILL PUSH THE HEAT INDEX INTO THE 100 TO 105 DEGREE RANGE...JUST SHY
OF ADVISORY CRITERIA.

FOR THE LAST HALF OF THE FORECAST THE DOMINATING BROAD NORTH
AMERICAN RIDGE WILL TRANSITION INTO A MORE AMPLIFIED WEST COAST
RIDGE/EAST COAST TROUGH PATTERN....ALLOWING FOR A SLIGHTLY COOLER
NORTHWEST FLOW TO PREVAIL ACROSS THE LOWER MISSOURI RIVER VALLEY FOR
THE LAST HALF OF THE WEEK. SO FAR THE MID RANGE MODELS HAVE BEEN IN
FAIRLY GOOD AGREEMENT ON THIS EXPECTED TRANSITION. THE ONE NOTABLE
CHANGE IS THAT THE EAST COAST TROUGH IS NOW PROGGED TO DIG A LITTLE
DEEPER/FASTER. AS THE EAST COAST TROUGH DEEPENS A LITTLE FRONTAL
BOUNDARY NOW APPEARS LIKELY TO MOVE THROUGH NORTHERN MISSOURI DURING
THE DAY TUESDAY. EXPECTATIONS ARE THAT FROPA ALONG WITH DIURNAL
HEATING COULD DESTABILIZE CONDITIONS JUST ENOUGH IN NORTH CENTRAL
AND NORTHEAST MISSOURI FOR SOME CONVECTION...HENCE THE ADDITION OF
CHANCE POPS FOR TUESDAY TO THOSE AREAS. OTHERWISE...WITH THE
NORTHWEST FLOW I HAVE KNOCKED TEMPS DOWN A LITTLE FOR THE LAST HALF
OF THE WORK WEEK...AND REMOVED POPS FROM WEDNESDAY NIGHT AND
THURSDAY AS SLIGHTLY COOLER HIGH PRESSURE WILL BE IN PLACE.

NRR/CUTTER

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1254 PM CDT SUN JUL 11 2004

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-121100-

...SCATTERED SEVERE THUNDERSTORMS PRODUCING DAMAGING WIND GUSTS AND
HAIL EXPECTED THIS AFTERNOON AND EVENING...

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

STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED ACROSS EXTREME NORTHERN
MISSOURI THIS AFTERNOON...MAINLY NORTH OF LINE FROM MOUND CITY TO
TRENTON TO KIRKSVILLE. THIS IS IN RESPONSE TO AN UPPER LEVEL
DISTURBANCE MOVING ACROSS THE MISSOURI-IOWA BORDER. OTHERWISE THE
ATMOSPHERE IS UNSTABLE ACROSS THE ENTIRE REGION...THEREFORE AN
ISOLATED STRONG TO SEVERE THUNDERSTORM REMAINS POSSIBLE JUST ABOUT
ANYWHERE ACROSS THE OUTLOOK AREA LATE THIS AFTERNOON INTO THE EARLY
EVENING HOURS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SCATTERED THUNDERSTORMS ARE POSSIBLE AGAIN MONDAY NIGHT...MAINLY
ACROSS EXTREME NORTHERN MISSOURI. THUNDERSTORMS ARE ALSO FORECAST
FOR LATE TUESDAY NIGHT AND EARLY WEDNESDAY MORNING. AT THIS
TIME...SEVERE THUNDERSTORMS LOOK POSSIBLE WITH ANY OF THIS ACTIVITY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED ACROSS NORTHERN MISSOURI THIS
AFTERNOON AND EVENING.

&&

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.

NRR

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1159 AM CDT SUN JUL 11 2004

MOZ001>008-011-015>017-112300-
ADAIR MO-ATCHISON MO-GENTRY MO-GRUNDY MO-HARRISON MO-HOLT MO-
MERCER MO-NODAWAY MO-PUTNAM MO-SCHUYLER MO-SULLIVAN MO-WORTH MO-
1159 AM CDT SUN JUL 11 2004

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
NUMBER 603...IN EFFECT UNTIL 600 PM CDT SUNDAY EVENING. THIS SEVERE
THUNDERSTORM WATCH INCLUDES THE FOLLOWING COUNTIES...

IN MISSOURI:

ADAIR...ATCHISON...GENTRY...GRUNDY...HARRISON...HOLT...MERCER...
NODAWAY...PUTNAM...SCHUYLER...SULLIVAN AND WORTH.

SOME CITIES IN THIS SEVERE THUNDERSTORM WATCH INCLUDE BETHANY...
KIRKSVILLE...MARYVILLE...ROCKPORT AND TRENTON.

A SEVERE THUNDERSTORM WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR
THE DEVELOPMENT OF SEVERE WEATHER...INCLUDING LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAIN...IN AND CLOSE TO THE WATCH AREA.
WHILE SEVERE WEATHER MAY NOT BE IMMINENT...PERSONS SHOULD REMAIN
ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS...AND LISTEN FOR LATER
STATEMENTS AND POSSIBLE WARNINGS.

NRR