Severe Thunderstorm Warning 153, NWS Kansas City, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
724 PM CDT FRI JUN 18 2010

.UPDATE...

EVENING ADJUSTMENT TO THE FORECAST...MOSTLY TO TRIM POP COVERAGE FOR
THE FIRST SIX HOURS...AND LIMIT POPS TO LESS THAN 40% AFTER MIDNIGHT.
EVENING ACTIVITY NEAR THE IOWA BORDER IS NOT HAVING ANY SUCCESS
CONGEALING INTO A LINER SYSTEM THAT WILL PUSH SOUTH DEEPER INTO
MISSOURI. LACK OF LOW LEVEL CONVERGENCE...OR ANY SEMBLANCE OF A
SHORTWAVE ALOFT...SEEMS TO HAVE LIMITED THE STORMS TO MOSTLY BEING
NORTH OF THE MISSOURI BORDER...WERE THE CAP IS A LITTLE WEAKER AND
SHEAR IS BETTER. LATE TONIGHT STORM ACTIVITY MIGHT GET GOING BACK
AGAIN IN THE WARM AIR ADVECTION ZONE...WHERE THE NOSE OF THE LOW
LEVEL JET AND LINGERING COLD FRONT INTERSECT IN NORTH CENTRAL
KANSAS/SOUTH CENTRAL NEBRASKA. IF THAT CONVECTION GETS GOING...
THOUGHTS ARE IT WOULD MOVE EAST DURING THE MORNING HOURS OF SATURDAY.
SO HAVE KEPT CHANCE POPS THROUGH THE EARLY MORNING HOURS FOR NOW.

CUTTER

&&

.DISCUSSION...

/411 PM CDT FRI JUN 18 2010/

SHORT TERM (TONIGHT THROUGH SATURDAY)...

EARLY MORNING CONVECTIVE COMPLEX...THAT MOVED EAST THROUGH IOWA
TODAY...PUT OUT A NICE BOUNDARY ACROSS THE FAR NORTHERN REACHES OF
MISSOURI THIS MORNING. HOWEVER...CONTINUED DEEP LAYER SOUTHERLY WINDS
AHEAD OF A COLD FRONT...CURRENTLY RESIDING JUST OFF THE FAR NORTHWEST
TIP OF MISSOURI FROM SOUTHWEST TO NORTHEAST...HAS PUSHED THAT
BOUNDARY UP INTO IOWA. VISIBLE SATELLITE IMAGERY INDICATES THAT THE
OUTFLOW BOUNDARY NOW TAILS BACK...AND IS INTERSECTING THE
FRONT...SOMEWHERE JUST TO THE SOUTH OF OMAHA. AGITATED CUMULUS CLOUDS
ACROSS SOUTHEAST NEBRASKA INDICATE THAT THE VERY WARM AND MOIST AIR
IN THE WARM SECTOR IS TRYING TO BREAK WHAT LITTLE CAP WAS SHOWN TO BE
IN PLACE BY THE 18Z SOUNDINGS FROM TOPEKA AND OMAHA. GIVEN LATEST RUC
ANALYSIS FROM SPC...MLCAPE VALUES ARE TIPPING THE SCALES AT AROUND
4000 J/KG. AFTERNOON WATER VAPOR IMAGERY SHOWS A RATHER LARGE FETCH
OF DRY AIR ALOFT ADVECTING INTO THE LOWER MISSOURI RIVER VALLEY
THANKS TO THE PERSISTENT SOUTHWEST FLOW AND DRY DESERT SOUTHWEST.

MODEL PREFERENCE IS NON-EXISTENT AS ALL THE MODELS HAVE BEEN HAVING
A DIFFICULT TIME PINNING DOWN ANY OF THE CONVECTIVE DETAILS OVER
RECENT DAYS. THEREFORE...FORECAST METHODOLOGY FOR TODAY THROUGH SATURDAY
IS BASED ON WHERE THE BOUNDARIES ARE...AND ARE EXPECTED TO BE...AND
GENERAL SYNOPTIC FEATURES. THIS RESULTS IN A RATHER LOW CONFIDENCE
FORECAST AFTER ABOUT THE FIRST 6 HOURS.

FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EARLY
EVENING...CONVECTION MIGHT START FIRING IN SOUTHEAST NEBRASKA NEAR
THE INTERSECTION OF THE FRONT AND OLD OUTFLOW BOUNDARY. WITH AMPLE
INSTABILITY TO TAP...THUNDERSTORMS SHOULD BE ABLE TO RAMP UP TO
SEVERE LEVELS RATHER QUICKLY...WITH SUFFICIENT SHEAR NORTH OF THE IOWA
BORDER TO ALREADY JUSTIFY A TORNADO WATCH...NORTH OF OUR FORECAST
AREA. BIG ISSUES WITH THIS IDEA THOUGH IS THE LACK OF GOOD LOW LEVEL
CONVERGENCE...AS SURFACE WINDS AND LOW LEVEL SHEAR ARE RATHER WEAK
GIVEN FLOW AROUND A WEAK SURFACE LOW IN NORTHEAST KANSAS/ SOUTHEAST
NEBRASKA...AND NO INITIATING UPPER LEVEL SHORTWAVE TO BE SEEN ON WATER
VAPOR. SO...WHILE ITS NOT A SURE THING...HAVE STILL LEANED THE
FORECAST TOWARDS EXPECTATION OF A LINE OF THUNDERSTORMS MOVING INTO
THE NORTHWEST CORNER FROM NEBRASKA...AND SPREADING EAST AND SOUTH
AFTER 00Z TONIGHT. EXPECT ANY STORMS THAT DEVELOP TO HAVE A HARD
TIME LASTING...OR MAKING IT...SOUTH OF THE MISSOURI RIVER AS SHEAR
SOUTH OF THE IOWA BORDER IS VERY POOR...AND AN EML SHOULD CAP THIS
REGION OFF. ANY STORMS THAT DO MAKE IT INTO OUR FORECAST AREA SHOULD
BE ACCOMPANIED BY A THREAT OF DAMAGING WINDS...GIVEN DRY AIR
ALOFT...AND HEAVY RAIN AS PRECIPITABLE WATER VALUES ARE ABOVE 1.5
INCHES.

FOR SATURDAY...IF ANYTHING CAN GET GOING TONIGHT...THERE MIGHT BE
LINGERING ACTIVITY ACROSS THE REGION DURING THE MORNING HOURS OF
SATURDAY. HOWEVER...THE CHANCE POPS ACROSS THE AREA FOR SATURDAY ARE
MOSTLY BASED ON THE IDEA OF ANY RESIDUAL OUTFLOW BOUNDARY THAT
MIGHT HAVE SETTLED ACROSS THE REGION OVERNIGHT THANKS TO ANY
CONVECTION OR THE FRONT. ANOTHER HOT AND HUMID DAY WILL PREVAIL
SATURDAY PROVIDING PLENTY OF FUEL FOR THUNDERSTORMS IF THEY CAN GET
GOING.

CUTTER

MEDIUM RANGE (SUNDAY THROUGH FRIDAY)...

BY SUN MORNING...AN AREA OF LOW PRESSURE WILL STILL BE SITUATED OVER
WESTERN KS...WITH A WARM FRONT EXTENDING EASTWARD OVER THE IA/MO
BORDER. CAN EXPECT PRECIP TO FORM NORTH OF THIS BOUNDARY THROUGH THE
EVENING HOURS. STILL SOME UNCERTAINTY REGARDING THE LOCATION OF THIS
FRONT. GFS AND NAM PUTTING THE FRONT OVER SOUTHERN IA...WHILE THE
ECMWF AND GEM SHOW THE FRONT SAGGING FURTHER SOUTHWARD OVER NORTHERN
MO. IF THE PATTERN PANS OUT LIKE THE ECMWF/GEM...COULD SEE SOME
SCATTERED PRECIP MOVING ACROSS EXTREME NORTHERN MO...AND THE PRECIP
COULD LINGER INTO MON. THIS PATTERN WILL REMAIN FAIRLY CONSISTENT
THROUGH TUES...BEFORE A MORE ZONAL-LIKE FLOW SETS UP WITH A WEAK
RIDGE DEVELOPING OVER THE CENTRAL CONUS. FOR THE REMAINDER OF THE
EXTENDED...MODELS ARE PICKING UP ON A FEW WAVES OVER THE NORTHERN
AND CENTRAL PLAINS...WITH SOME POTENTIALLY CLIPPING THE NORTHERN
CWA. HOWEVER...BETWEEN THE UNCERTAINTY AMONGST THE MODELS AND THE
INCONSISTENCY BETWEEN CONSECUTIVE MODEL RUNS...HAVE KEPT POPS AT
ONLY SLIGHT CHANCES FOR EXTREME NORTHERN MO DURING THE LATTER HALF
OF THE PERIOD.

TEMPERATURES WILL BE A MAIN FOCUS FOR THE EXTENDED PERIOD.
CURRENTLY EXPECTING TEMPS TO REACH INTO THE UPPER 80S AND LOW/MID
90S FOR MUCH OF THE WEEK...WITH HEAT INDICES NEAR 100 DEGREES
POSSIBLE FOR THE SOUTHERN HALF OF THE CWA.

ACH

&&

.AVIATION...

FOR THE 00Z TAFS...EARLIER THOUGHTS ON CONVECTIVE INITIATION IN
SOUTHEAST NEBRASKA DID NOT WORK OUT SO WELL. INITIATION IS GOING ON A
TOUCH FARTHER EAST...AND AS A RESULT CONVECTION IS NO LONGER EXPECTED
TO REACH THE KANSAS CITY TERMINALS OVERNIGHT. HAVE LEFT VICINITY
THUNDER IN THE KSTJ TERMINAL FARTHER NORTH...BUT EVEN THAT ACTIVITY
LOOKS LIKE IT WILL SHIFT EAST QUICKLY THIS EVENING. OTHERWISE...
WITHOUT THE CONVECTION TO PUSH A SURFACE BOUNDARY SOUTH HAVE STEERED
WINDS BACK TO A PREVAILING SOUTHERLY DIRECTION OVERNIGHT WITH
SOUTHEAST WINDS DURING THE DAY SATURDAY. DO HAVE SOME THOUGHTS THAT
CONVECTION MIGHT TRY TO DEVELOP ACROSS THE TERMINALS TOMORROW IN THE
HEAT OF THE AFTERNOON...BUT AT THIS TIME BELIEVE WE HAVE NO SKILL IN
ACTUALLY FORECASTING THAT...SO WILL LEAVE FORECAST DRY FOR NOW.

CUTTER

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
708 PM CDT FRI JUN 18 2010

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-200015-
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-
708 PM CDT FRI JUN 18 2010

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

.DAY ONE...TONIGHT

ONGOING CONVECTION IN FAR NORTHERN MISSOURI WILL SLOWLY PUSH EAST
THROUGH THE EVENING HOURS. MOST ACTIVITY IS EXPECTED TO REMAIN NEAR
AND NORTH OF THE IOWA BORDER...THOUGH THESE STORMS MAY AFFECT AREAS
IN THE NORTHERN MOST TWO TIERS OF COUNTIES OF NORTH CENTRAL AND
NORTHEAST MISSOURI THROUGH MIDNIGHT. MAIN THREATS WITH ANY STORMS
THAT OCCUR SOUTH OF THE IOWA BORDER WILL BE FROM DAMAGING WINDS AND
HEAVY RAIN.

OTHERWISE...LATE TONIGHT THUNDERSTORM ACTIVITY MAY TAKE OFF AGAIN
ACROSS NORTH CENTRAL KANSAS/SOUTH CENTRAL NEBRASKA AND MOVE EAST
DURING THE EARLY MORNING HOURS. POTENTIAL FOR THIS TO OCCUR APPEARS LOW
AT THIS TIME...BUT THERE IS THE POTENTIAL. ONCE AGAIN...MAIN THREAT
WITH ANY THUNDERSTORMS THAT MOVE THROUGH WILL BE FROM DAMAGING WINDS
AND HEAVY RAIN.

MINOR TO MODERATE RIVER FLOODING IS OCCURRING OR IS FORECAST ALONG
SEVERAL RIVERS IN THE OUTLOOK AREA. PLEASE SEE THE APPROPRIATE FLOOD
WARNING OR FLOOD STATEMENT FOR SPECIFIC DETAILS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORMS MAY BE ONGOING SATURDAY MORNING ACROSS THE OUTLOOK
AREA...DISSIPATING BY MID-MORNING IF THEY ARE STILL IN THE REGION.
OTHERWISE...WARM AND MUGGY CONDITIONS WILL CONTINUE SATURDAY WITH
TEMPERATURES EXPECTED TO REACH THE LOWER 90S AND AFTERNOON HEAT
INDICES AROUND 100 DEGREES.

A NEARLY STATIONARY FRONT WILL TAKE UP RESIDENCE FROM SOUTHERN
NEBRASKA AND NORTHERN KANSAS EAST TO SOUTHERN IOWA AND NORTHERN
MISSOURI SATURDAY THROUGH TUESDAY. A SERIES OF WEAK UPPER LEVEL
DISTURBANCES MAY TRIGGER PERIODIC ROUNDS OF THUNDERSTORMS SATURDAY
THROUGH TUESDAY IN THE VICINITY OF THE BOUNDARY...MAINLY IN NORTHERN
MISSOURI ALONG AND NORTH OF ROUTE 36. SEVERE WEATHER WILL BE POSSIBLE
ALONG WITH THE POTENTIAL FOR HEAVY RAINFALL.

OUTSIDE OF THUNDERSTORM ACTIVITY...VERY WARM AND HUMID CONDITIONS
WILL CONTINUE INTO EARLY NEXT WEEK. TEMPERATURES IN THE 90S COMBINED
WITH HIGH RELATIVE HUMIDITIES WILL PRODUCE HEAT INDICES AROUND 100.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THIS EVENING...BUT MAY BE
REQUIRED SATURDAY OR SUNDAY IN AREAS NEAR THE IOWA BORDER.

CUTTER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
819 PM CDT FRI JUN 18 2010

MOZ007-008-190200-
PUTNAM MO-SCHUYLER MO-
819 PM CDT FRI JUN 18 2010

...SIGNIFICANT WEATHER ADVISORY FOR SCHUYLER AND NORTHERN PUTNAM
COUNTIES UNTIL 900 PM CDT...

AT 817 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 27 MILES NORTHEAST
OF SEYMOUR TO 20 MILES NORTHWEST OF LANCASTER TO 11 MILES EAST OF
SEYMOUR TO 12 MILES SOUTHWEST OF SEYMOUR...AND MOVING EAST AT 50 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THESE STORMS...ALONG WITH FREQUENT DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE...
  UNIONVILLE...LANCASTER...DOWNING...QUEEN CITY...GLENWOOD...LIVONIA
  AND WORTHINGTON.

THESE STORMS MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4036 9235 4034 9242 4054 9336 4059 9324
      4060 9236
TIME...MOT...LOC 0119Z 286DEG 43KT 4094 9271 4076 9271
          4065 9288 4056 9325

DUX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
838 PM CDT FRI JUN 18 2010

MOZ002>005-190215-
GENTRY MO-HARRISON MO-NODAWAY MO-WORTH MO-
838 PM CDT FRI JUN 18 2010

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN NODAWAY...NORTHWESTERN
HARRISON...NORTHERN GENTRY AND SOUTHEASTERN WORTH COUNTIES UNTIL 915
PM CDT...

AT 833 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 12 MILES NORTHEAST
OF GRANT CITY TO GRANT CITY TO 7 MILES SOUTHWEST OF GRANT CITY TO
RAVENWOOD...AND MOVING EAST AT 20 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THESE STORMS...ALONG WITH HEAVY RAIN. THESE STORMS MAY
BE CAPABLE OF PRODUCING VERY WEAK FUNNEL CLOUDS ALOFT AS THEY REMAIN
TIED TO A WEAK COLD FRONT.

LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE...
  EAGLEVILLE...NEW HAMPTON...WORTH...ALLENDALE...HATFIELD...DENVER...
  GENTRY AND MARTINSVILLE.

THESE STORMS MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

LAT...LON 4037 9401 4025 9419 4030 9471 4043 9458
      4058 9435 4058 9384
TIME...MOT...LOC 0137Z 291DEG 18KT 4056 9419 4047 9432
          4040 9447 4033 9460

31

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
845 PM CDT FRI JUN 18 2010

MOZ006-007-190230-
MERCER MO-PUTNAM MO-
845 PM CDT FRI JUN 18 2010

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN PUTNAM AND NORTHEASTERN
MERCER COUNTIES UNTIL 930 PM CDT...

AT 843 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 12 MILES SOUTHWEST OF SEYMOUR...OR 17 MILES
NORTHWEST OF UNIONVILLE...MOVING EAST AT 40 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  UNIONVILLE.

THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4058 9272 4056 9270 4043 9273 4049 9346
      4058 9339 4059 9272
TIME...MOT...LOC 0145Z 272DEG 33KT 4058 9328

DUX