Flash Flood Warning 15, NWS Kansas City, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1215 AM CDT FRI JUN 1 2007

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...

COMPLEX FORECAST THROUGH THE NEXT 48 TO 60 HRS AS SLOW MOVING
NORTHERN PLAINS UPPER LOW TRANSITIONS EASTWARD. STRONG TO SEVERE
THUNDERSTORMS EXPECTED TO DEVELOP ACROSS THE HIGH PLAINS THIS
AFTERNOON AND EVENING WITH INITIAL DEVELOPMENT ALREADY ONGOING ACROSS
NORTHWESTERN KS/SW NEBRASKA. THIS ACTIVITY IS EXPECTED TO CONGEAL
INTO ONE OR MORE THUNDERSTORM CLUSTERS/MCS OVERNIGHT ACROSS CENTRAL
KS/NE. THIS WILL LIKELY BE SUSTAINED BY 50-60KT H5 FLOW ATOP
STRENGTHENING 40-50KT LLJ FOCUSING ACROSS THE CENTRAL PLAINS. LLJ
PROGGED TO VEER OVERNIGHT AND BECOME MORE FOCUSED ACROSS CENTRAL TO
EASTERN KANSAS AND INTO NORTHERN OKLAHOMA TOWARD THE MORNING HOURS
ALLOWING ISENTROPIC ASCENT TO INCREASE ACROSS EASTERN KANSAS AND INTO
WESTERN MISSOURI...MOST NOTICEABLE ALONG 300K SFC. THIS WILL PROVIDE
SUFFICIENT LIFT FOR ACTIVITY TO DEVELOP/SPREAD EASTWARD INTO THE FORECAST
AREA DURING THE MORNING HOURS. CURRENTLY SUSPECT AS TO AMOUNT OF
OVERNIGHT MCS THAT WILL MAKE IT INTO THE FORECAST AREA GIVEN POSITION
OF LLJ AXIS AND THETA E TONGUE. IN ADDITION...GIVEN DEEP LAYER SHEAR AND
AMOUNT OF INSTABILITY EXPECTED...ONLY AN ISOLATED HAIL/DAMAGING WIND
THREAT WOULD BE EXPECTED WITH ANY OF THE STRONGER ACTIVITY THAT WOULD
MAKE IT INTO THE AREA.

ATTENTION THEN TURNS TO CONVECTIVE POTENTIAL TOMORROW AFTERNOON AND
EVENING AS COLD FRONT PUSHES EASTWARD INTO EASTERN NE/KS AND WARM
FRONT LIFTS INTO IA PLACING THE FORECAST AREA IN THE WARM SECTOR.
CURRENT INDICTATIONS SUGGEST A LULL IN THE ACTIVITY BETWEEN DECAYING
MORNING MCS AND EXPECTED ADDITIONAL AFTERNOON DEVELOPMENT.
ATTM...EXTENT OF SVR POTENTIAL WILL DEPEND ON AMOUNT OF DAYTIME
HEATING AND SUBSEQUENT INSTABILITY REALIZED IN THE WAKE OF MORNING
CONVECTIVE DEBRIS. COLD FRONT SHOULD BE THE FOCUS FOR AFTERNOON
INITIATION MAINLY ACROSS EASTERN NE/KS. FAVORABLE SPEED SHEAR WILL BE
IN PLACE FOR STORM ORGANIZATION AS 30-40KT H5 FLOW OVERSPREADS
EASTERN KS/WESTERN MISSOURI DURING THE EVENING HOURS. DIRECTIONAL
SHEAR IS SOMEWHAT LACKING AS LLJ REMAINS VEERED ALTHOUGH SFC FLOW CONTINUES
WITH A SOUTHERLY COMPONENT. IN ADDITION...MORE BACKED WINDS IN THE
H5-H25 LAYER WOULD LEND TO NORTHERLY ANVIL LEVEL BLOW OFF AND
SUBSEQUENT CELL SEEDING GIVEN STORM MOTIONS. ALSO WITH VEERED LLJ AND
FAIRLY WEAK SFC FLOW LIKELY LIMITING EXTENT OF LOW LEVEL
HODOGRAPHS...SUBSEQUENT TORNADIC THREAT WILL REMAIN LIMITED.
HOWEVER...IF SUFFICIENT INSTABILITY IS REALIZED AND DISCRETE STORM
MODES INITIATE...AN ISOLATED TORNADO CANNOT BE RULED OUT...ESPECIALLY
WITH ANY DEVIANT STORM MOTION. OTHERWISE...CURRENT INDICATIONS ARE
THAT LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN SVR THREATS. IN
ADDITION...GIVEN INCREASING LL MOISTURE AND PWS REACHING 1 TO 1.5
INCHES ACROSS THE AREA...A HEAVY RAIN POTENTIAL/FLASH FLOODING THREAT
WILL EXIST. WILL THEREFORE RAISE A FLASH FLOOD WATCH FROM 12Z FRI
THROUGH 12Z SAT FOR THE NORTHWESTERN 2/3RD OF COUNTIES. THIS SEEMS
JUSTIFIED BASED ON LATEST FFG OF LESS THAN AN INCH IN MANY AREAS AND
18Z HPC QPG GUIDANCE OF 1-1.5 INCHES WITH HIGHER ISOLATED AMOUNTS
POSSIBLE.

FRONT MAKES SLOW PROGRESS ACROSS THE REMAINDER OF THE CWA DURING THE
DAY SATURDAY AND SHOULD PUSH OUT OF THE AREA SAT NIGHT. HAVE
THEREFORE TRENDED POPS DOWN THROUGH THE DAY SAT AS LLJ FOCUSED
FURTHER EAST AND UPPER TROUGH AXIS SHIFTS INTO THE UPPER MIDWEST.

DEROCHE

EXTENDED (SUNDAY TO THURSDAY)...

MAIN CONCERNS IN THE MEDIUM RANGE PORTIONS OF THE FORECAST DEAL WITH
LINGERING PRECIP CHANCES AS WELL AS TEMPERATURES DURING NEXT WEEK.
FOR SUNDAY AND MONDAY...PESKY UPR-LOW WILL CONTINUE TO SLOWLY WOBBLE
EASTWARD.  CAA WRAPPING AROUND THE BACKSIDE OF THE UPR LOW COMBINED
WITH THE DIURNAL HEATING OF THE DAY WILL LEAD TO A SLIGHT CHANCE FOR
SHOWERS ACROSS MAINLY THE NORTHEAST THIRD OF THE CWA DURING THE DAY
ON SUNDAY. TEMPERATURES COULD BE A LITTLE TRICKY SUNDAY AND
MONDAY...IF UPR LOW DRIFTS SLIGHTLY FURTHER SOUTH...THERE COULD BE
ENOUGH STRATO-CU DEVELOPMENT TO HAMPER TEMPERATURES. AS A RESULT...LATER
SHIFTS MAY NEED TO LOWER TEMPS ESPECIALLY IN THE NORTHEAST CORNER OF
THE CWA.

BY MONDAY AFTERNOON MID-LVL RIDGING WILL BECOME BETTER ESTABLISHED
ACROSS THE CENTRAL CONUS. THIS SHOULD ALLOW FOR DRY WEATHER TO
PREVAIL THROUGH WEDNESDAY...WITH TEMPERATURES MODERATING INTO THE
LOWER 80S. MED RANGE MODELS BEGIN TO DIFFER BY WED AS STRONG UPR-LVL
WAVE PUSHES INTO THE PAC NW.  THE ECMWF IS MUCH STRONGER AND FURTHER
SOUTH WITH THIS WAVE...WHILE THE GFS MAINTAINS A MORE PROGRESSIVE
FEATURE NEAR THE CANADIAN BORDER.  REGARDLESS...APPEARS THE NEXT
SIGNIFICANT CHANCE FOR PRECIP WILL ARRIVE SOMEWHERE IN THE MID-LATE
WEEK TIMEFRAME.  AS FAR AS TEMPERATURES ARE CONCERNED...BOTH THE
GFS/ECMWF ADVERTISE 85H TEMPS APPROACHING 18-20 DEGREES C BY
WEDNESDAY AND THURSDAY AS LEE TROUGHING COMMENCES.  THIS WOULD PUSH
READINGS INTO SUMMERLIKE TERRITORY...WITH THE MID-UPR 80S
PREVAILING.

DUX

&&

.AVIATION...

THE SQUALL LINE IN EASTERN KANSAS IS EXPECTED TO WEAKEN AS IT
APPROACHES WESTERN MISSOURI DUE TO WEAK SHEAR AND WEAK ELEVATED
INSTABILITY. NEVERTHELESS...SHOWERS AND THUNDERSTORMS WILL AFFECT
THE KANSAS CITY METRO AREA AFT 09Z AND CONTINUE UNTIL ABOUT 15Z.
SHOWERS AND THUNDERSTORMS WILL LIKELY REDEVELOP LATE THIS AFTERNOON
AND TONIGHT AS A COLD FRONT APPROACHES. OTHERWISE...CONDITIONS WILL
MAINLY BE VFR EXCEPT LOCALLY MVFR/IFR DURING CONVECTIVE ACTIVITY.

DB

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 7 AM SATURDAY FOR MOZ001-
     MOZ002-MOZ003-MOZ004-MOZ005-MOZ006-MOZ011-MOZ012-MOZ013-
     MOZ014-MOZ015-MOZ020-MOZ021-MOZ022-MOZ023-MOZ028-MOZ029-
     MOZ030-MOZ031-MOZ037-MOZ038.

KS...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 7 AM SATURDAY FOR KSZ025-
     KSZ102-KSZ103-KSZ104-KSZ105.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
348 PM CDT THU MAY 31 2007

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-011200-
ATCHISON KS-MIAMI-LINN KS-DONIPHAN-LEAVENWORTH-WYANDOTTE-
JOHNSON KS-ATCHISON MO-NODAWAY-WORTH-GENTRY-HARRISON-MERCER-
PUTNAM-SCHUYLER-HOLT-ANDREW-DE KALB-DAVIESS-GRUNDY-SULLIVAN-ADAIR-
BUCHANAN-CLINTON-CALDWELL-LIVINGSTON-LINN MO-MACON-PLATTE-CLAY-
RAY-CARROLL-CHARITON-RANDOLPH-JACKSON-LAFAYETTE-SALINE-HOWARD-
CASS-JOHNSON MO-PETTIS-COOPER-BATES-HENRY-
348 PM CDT THU MAY 31 2007

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

.DAY ONE...REST OF THIS AFTERNOON AND TONIGHT

SEVERAL THUNDERSTORM COMPLEXES ARE EXPECTED TO DEVELOP LATE THIS
AFTERNOON AND EVENING ACROSS WESTERN KANSAS AND CENTRAL NEBRASKA.
THIS ACTIVITY MAY REACH EASTERN KANSAS AND EXTREME WESTERN MISSOURI
BY DAYBREAK. ALTHOUGH THE STORMS ARE EXPECTED TO BE BELOW SEVERE
LIMITS...SMALL HAIL IS POSSIBLE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS WILL LIKELY BE ONGOING FRIDAY MORNING. ISOLATED SEVERE
THUNDERSTORMS MAY PRODUCE LARGE HAIL AND DAMAGING WINDS. IN
ADDITION...HEAVY RAIN IS POSSIBLE WITH THE POTENTIAL FOR FLASH
FLOODING FOR MUCH OF THE OUTLOOK AREA.

A CONDITIONAL THREAT FOR ADDITIONAL SEVERE THUNDERSTORM DEVELOPMENT
WILL EXIST ACROSS THE OUTLOOK AREA FRIDAY AFTERNOON AND EVENING.
THIS SCENARIO WILL DEPEND ON WHETHER THE ATMOSPHERE CAN
SUFFICIENTLY DESTABILIZE IN THE WAKE OF THE MORNING THUNDERSTORMS. IF
THE ATMOSPHERE CAN DESTABILIZE SUFFICIENTLY...SEVERE THUNDERSTORMS
WILL BE POSSIBLE AS A WARM FRONT LIFTS ACROSS EASTERN KANSAS AND
MISSOURI. IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...SUFFICIENT
SHEAR MAY LEAD TO THE DEVELOPMENT OF ISOLATED TORNADOES. THE THREAT
OF HEAVY RAIN WILL CONTINUE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. SPOTTER
ACTIVATION MAY BE NEEDED ON FRIDAY...ALONG WITH ANY REPORTS OF
SIGNIFICANT RAINFALL.

DB