Hail and Damaging Winds in Kansas, May 29 to 30, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
631 PM CDT TUE MAY 29 2012

...UPDATE TO AVIATION...

.DISCUSSION...

19Z WATER VAPOR SHOWS THE MEAN WESTERLIES WELL NORTH ACROSS CANADA
AND THE NORTHERN PLAINS. A COUPLE WAVES WERE MOVING EAST...ONE
MOVING INTO THE NORTHERN ROCKIES. THIS LEAVES QUASI-ZONAL FLOW OVER
KS. AT THE SFC...19Z OBS SHOWS THE FRONT /OR AT LEAST THE WIND
SHIFT/ HAS PUSHED SOUTH INTO SOUTHEAST KS. THERE IS STILL A GOOD
MOISTURE GRADIENT ACROSS ANDERSON AND COFFEY COUNTIES WHERE A CU
FIELD IS SEEN TRYING TO EXPAND ON VISIBLE IMAGERY.

FOR TONIGHT WITH A LACK OF LARGE SCALE FORCING...PRECIP CHANCES WILL
BE DEPENDENT INITIALLY ON DIURNAL HEATING EARLY AND THEN THE LOW
LEVEL JET AND ISENTROPIC LIFT OVERNIGHT. WITH THE BOUNDARY SOUTH OF
ANDERSON AND COFFEY COUNTIES...IT APPEARS THE BETTER CHANCES FOR
EVENING CONVECTION WILL BE MAINLY SOUTH OF THE FORECAST AREA.
OVERNIGHT...THE NAM APPEARS TO BE THE ONLY MODEL WITH STRONG ENOUGH
MOISTURE ADVECTION BETWEEN 800 AND 700MB FOR THE ISENTROPIC LIFT TO
ACT UPON. THIS MAY BE A LITTLE OVERDONE GIVEN A GENERAL LACK OF
MOISTURE SEEN WITHIN THIS LAYER FROM THE OUN AND AMA SOUNDINGS THIS
MORNING. SO WHILE I CAN NOT COMPLETELY RULE OUT ELEVATED
CONVECTION...AM NOT OVERLY EXCITED ABOUT THE PROSPECTS. THEREFORE
HAVE GONE WITH SLIGHT CHANCES. ELEVATED INSTABILITY IS RELATIVELY
MARGINAL SO PROSPECTS FOR SEVERE WEATHER APPEAR TO BE LOW. THINKING
THE NIGHT IS MORE LIKELY TO BE CLEAR AND DRY...HAVE MIN TEMPS IN
LINE WITH COOLER MOS GUIDANCE GIVEN RELATIVELY LOW DEWPOINTS AND
SURFACE RIDGING.

WEDNESDAY IS A LITTLE MORE COMPLICATED WITH PRECIP CHANCES. MODELS
ARE STARTING TO KICK OUT SOME ENERGY BY THE AFTERNOON AS THE WAVE
OVER THE NORTHWEST DIVES SOUTHEAST THROUGH THE PLAINS. WITH THE
ECMWF STILL HINTING AT SOME KIND OF A MCS MOVING SOUTHEAST THROUGH
KS...THERE REMAINS A GOOD DEAL OF UNCERTAINTY IN LOCATION OF PRECIP.
NEVERTHELESS IT APPEARS THAT THE PROBABILITY FOR PRECIP SHOULD BE
INCREASING THROUGH THE DAY AND HAVE TRENDED THE POPS UP DURING THE
AFTERNOON WEDNESDAY. BETTER INSTABILITY SHOULD BE SOUTH OF THE
FORECAST AREA WHERE THE HIGHER DEWPOINTS REMAIN. MAIN CONCERN WILL
BE TEMPS GIVEN INCREASED CLOUD COVER AND NEUTRAL TEMP ADVECTION
THANKS TO AN EASTERLY LOW LEVEL WIND. THINK HIGHS SHOULD REMAIN IN
THE 70S.

WOLTERS

CHANCE FOR RAIN CONTINUES INTO WEDNESDAY NIGHT AS STRONG
SHORTWAVE TROF DROPS ACROSS THE NORTHERN PLAINS INTO THURSDAY
MORNING. CONCERNED THAT BETTER RAINFALL WILL OCCUR SOUTH OF THE
AREA WHERE AIR IS MORE UNSTABLE ALONG THE SURFACE FRONT...OR TO
THE NORTHEAST WHERE CONVERGENCE IN THE COLUMN AND BETTER SYNOPTIC
LIFT COME TOGETHER. EC SOLUTION BRINGS 850MB DEFORMATION ACROSS
THE AREA AND THAT WOULD GIVE MORE LIFT FOR BETTER CHANCES OF
ACCUMULATING RAINFALL. HAVE GENERALLY LESS THAN HALF AN INCH IN
THE FORECAST BUT HOPEFUL FOR LOCALLY HIGHER AMOUNTS. ANY PRECIP
CHANCES FOR THURSDAY AFTERNOON WILL DEPEND ON HOW FAR SOUTH THE
UPPER LOW TRACKS AND HAVE KEPT SOME PRECIP CHANCES CLEARING
QUICKLY TO THE EAST INTO THE EVENING HOURS. AIRMASS BEHIND THE
UPPER LOW IS QUITE COOL...AND HAVE HIGHS IN THE 60S THURSDAY WITH
NEAR 70 FOR FRIDAY.

WEATHER PATTERN TRANSITIONS INTO SATURDAY AS WESTERN RIDGE
AMPLIFIES AND FRONT RETREATS BACK NORTHWARD. KEPT A SLIGHT CHANCE
FOR SOME STORMS SATURDAY AS FRONT MOVES NORTH...OTHERWISE EXPECT
TEMPERATURES TO CLIMB BACK INTO THE 80S FOR SATURDAY WITH MIDDLE
80S TO NEAR 90 WEST POSSIBLE SUNDAY. PRECIPITATION CHANCES FOR
MONDAY AND TUESDAY WILL DEPEND ON HOW MUCH RIDGING PLAYS OUT IN
THE UPPER PATTERN AND WHERE THE SURFACE FRONT BECOMES
ORIENTED. BOTH EC AND GFS SEND A BACK DOOR COLD FRONT TOWARD THE
CWA BEHIND THE UPPER TROF MOVING OFFSHORE THE EAST COAST. THE EC
SLIGHTLY MORE AMPLIFIED AND WARMER WITH THE RIDGING WHILE THE GFS
MORE ZONAL...WITH THE BOUNDARY IN NEBRASKA MOVING INTO THE
NORTHERN COUNTIES FOR TUESDAY. COULD GET SOME PRETTY WARM
TEMPERATURES IF WE END UP MIXING INTO THE THERMAL RIDGE...OR
COULD GET LUCKY AND GET SOME RAIN IF THE FRONT MOVES SOUTH. KEPT A
CON CENSUS FORECAST OF WARMER TEMPERATURES WITH INCREASING RAIN
CHANCES INTO TUESDAY. 67

&&

.AVIATION...
WILL KEEP TAFS VFR FOR THIS CYCLE. SOME CONCERN FOR CONVECTION IN
THE 04Z-11Z RANGE BUT TOO MUCH UNCERTAINTY ON DEVELOPMENT AND
COVERAGE FOR INCLUSION. MORE CONVECTION POSSIBLE IN THE LATTER
SEVERAL HOURS BUT CONFIDENCE IS AGAIN LACKING. EAST TO NORTHEAST
WINDS IN DRY LOW LEVELS WILL CONTINUE FOR THE BULK OF THE FORECAST.

65

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
346 PM CDT TUE MAY 29 2012

KSZ008>012-020>024-026-034>040-054>056-058-059-302100-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
346 PM CDT TUE MAY 29 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL...NORTH
CENTRAL AND NORTHEAST KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS...GENERALLY ALONG AND
SOUTH OF INTERSTATE 70 FROM LATE THIS AFTERNOON THROUGH EARLY
EVENING. THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE
ENTIRE NORTHEAST KANSAS AREA AFTER MIDNIGHT WEDNESDAY.

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

THUNDERSTORM CHANCES WILL SPREAD SOUTHEAST ACROSS THE ENTIRE AREA
WEDNESDAY AFTERNOON AND WILL CONTINUE WEDNESDAY NIGHT AND MUCH OF
THURSDAY.

ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS EXIST ON FRIDAY
EVENING THROUGH SATURDAY AFTERNOON...AND THEN ONCE AGAIN FROM SUNDAY
EVENING TO TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.