Severe Thunderstorm Warning 117, NWS Topeka, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
235 PM CDT SUN JUN 7 2009

.DISCUSSION...
CONCERNS FOR SHORT TERM ARE WITH SEVERE POTENTIAL THIS AFTERNOON AND
EVENING.

ATMOSPHERE OVER NE KS BECOMING INCREASINGLY UNSTABLE AFTER GOOD
SUNSHINE AND WITH STEADY FETCH OF MID TO UPPER 60S DEWPOINTS INTO
MUCH OF OUR AREA. FRONTAL BOUNDARY LINGERS IN OUR WESTERN BORDER AS
LOW PRESSURE DEVELOPS OVER CTR KS. NORTHERN PORTION OF THE BOUNDARY
RESIDES NEAR THE KS/NE BORDER.  STRONG SHORTWAVE MOVING EASTWARD
OUT OF WESTERN COLORADO EXPECTED TO INSTIGATE STORMS BY THE LATE
AFTERNOON HOURS. SOUNDING GOING UP ATTM...BUT APPEARS FOR NOW THAT
CAP IS HOLDING OVER SOUTHERN PORTION OF THE CWA. RUC DOES ANALYZE A
20J/KG WEAK SPOT IN THE CIN OVER THE MANHATTAN AREA AND
NORTHWARD...AND WITH SOME CONVERGENCE IN THE WIND FIELDS...ALSO SEEN
BY A FINE LINE ON THE RADAR...WILL HAVE EYE ON THIS AREA INITIALLY.
MODELS STILL OVERDOING THE CAPE WITH TDS PROGGED IN THE
70S...HOWEVER WIDESPREAD 2-3K J/KG WOULD BE REPRESENTATIVE
CONSIDERING REAL TDS.  INITIAL 0-1KM SHEAR NEAR PRESSURE
TROUGH/SURFACE BOUNDARY AND OVER ALL OF NORTHEAST KS NOT TOO
IMPRESSIVE WITH LESS THAN 10 KTS.  PLENTY OF DEEPER LAYER SHEAR WITH
0-6KM AT 30-50KTS...SO SUPERCELLS HAVE PLENTY OF SUPPORT. EXPECT
THESE TO INCREASE LATER TODAY AS STRONGER WINDS APPROACH ALOFT WITH
WAVE. INITIAL CONCERNS WOULD BE LARGE HAIL GIVEN STRONG INSTABILITY
AND RELATIVELY MOIST AIR MASS IN THE LOW LEVELS...BUT WITH SOME
TURNING OF THE WINDS AND POTENTIAL QUICK DEVELOPMENT IN STRONG
INSTABILITY CANNOT RULE OUT A TORNADO THREAT.  FRONT SHOULD GET A
GOOD PUSH FROM THE UPPER WAVE AND MOVE ACROSS THE AREA BY 12Z.
BETTER INSTABILITY LIFTS NORTHEAST AS LLJ STRENGTHENS AND EXPECT
CONVECTION TO FOLLOW. STILL ANTICIPATE STORMS ALONG THE FRONTAL
BOUNDARY LATER TONIGHT BUT WITH STRONGER THREAT FOCUSED NORTH.   67

AFTER A DRY MONDAY...SURFACE RIDGE BEGINS RETREATING EASTWARD MONDAY
NIGHT...BUT DRY CONDITIONS SHOULD CONTINUE THROUGH THE NIGHT.  GFS
AND NAM BEGIN SIG DISAGREEMENT AT THAT POINT IN POSITION OF WARM
FRONT DEVELOPING TO EAST OF LEE LOW.  GFS BRINGS THIS WARM FRONT
NORTHWARD WITH THE GREATEST PRECIP THREAT ON TUESDAY OVER NORTHEAST
KS AND AREAS N.  NAM ON THE OTHER HAND KEEPS BOUNDARY ACROSS NRN OK
AND INFERRED CONVECTIVE COMPLEX MOVING THROUGH EC KS.  HAVE GONE
SLIGHTLY CLOSER TO NAM SOLUTION...BUT HAVE SOMEWHAT BROADBRUSHED
PRECIP CHANCES ACROSS ENTIRE AREA DUE TO UNCERTAINTY.

BEYOND THAT...WE STAY IN NEARLY ZONAL FLOW WITH DISTURBANCES
PERIODICALLY COMING THROUGH.  TIMING OF THESE VERY CHALLENGING IN
THIS EXTENDED TIME FRAME BUT HAVE CHANCES EVERY DAY. FOR THE MOST
PART...GFS KEEPS SURFACE LOW AND ASSOCIATED WARM FRONT TO THE SOUTH
OUR AREA UNTIL LATE IN THE WEEKEND...WHICH WOULD KEEP SURFACE BASED
SEVERE WEATHER THREAT TO OUR SOUTH.  12Z ECMWF ON THE OTHER HAND
DOES BEING A SYSTEM OUT FARTHER TO THE N NEXT WEEKEND WITH WARMER
TEMPERATURES AND A BETTER CHANCE OF MORE SIGNIFICANT STORMS.  GIVEN
ISSUES THAT LONG RANGE MODELS HAVE HAD...HAVE JUST BROADBRUSHED POPS
DURING NEXT WEEKEND WITH CLOSE TO HPC TEMPERATURES WHICH WERE BASED
PARTLY ON ECMWF ENSEMBLE.   60

&&

.AVIATION...
STORM CHANCES WILL BE PRIMARY CONCERN THIS TAF PERIOD. LATER
MODELS SUGGESTING WE COULD SEE SOME DEVELOPMENT AROUND THE 20-21Z
TIMEFRAME NEAR THE TAF SITES. KEPT VCTS BUT ADJUSTED THE TIMES.
THESE STORMS WILL BE STRONG AND WOULD EASILY BRING IFR/LIFR
CONDITIONS TO THE SITES AND WILL AMEND AS THEY DEVELOP SINCE NOT
ONE SURE LOCATION WHERE THEY WILL START. FRONT PASSES OVERNIGHT
AND COULD BRING LOW STRATUS. STARTED WITH A SCT010 GROUP AND MAY
HAVE TO HIT HARDER AT LATER TAF ISSUANCES.  67

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
222 PM CDT SUN JUN 7 2009

KSZ008>012-020>024-026-034>040-054>056-058-059-081200-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
222 PM CDT SUN JUN 7 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

A NEARLY STATIONARY FRONT OVER NORTH CENTRAL KANSAS WILL BEGIN TO
SLOWLY SAG SOUTHEAST THIS EVENING AND BE LOCATED ALONG THE KANSAS
TURNPIKE BY MIDNIGHT TONIGHT. AN UPPER LEVEL DISTURBANCE OVER
WESTERN KS APPROACHES THE AREA THIS AFTERNOON...WITH THUNDERSTORMS
EXPECTED TO DEVELOP AFTER 230 PM. THE THUNDERSTORMS ARE EXPECTED TO
THEN BECOME MORE NUMEROUS ACROSS THE AREA THROUGH THE EVENING
HOURS...PARTICULARLY OVER NORTHEAST KANSAS...AS A STRONGER WAVE
APPROACHES THIS EVENING AND OVERNIGHT.

SOME OF THE THUNDERSTORMS WILL LIKELY BECOME SEVERE QUICKLY WITH
VERY LARGE HAIL AND STRONG WINDS. TORNADOES WILL ALSO BE A
POSSIBILITY THROUGH THE EVENING HOURS. THE COVERAGE AND INTENSITY
OF THE THUNDERSTORMS SHOULD BEGIN TO DECREASE AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

IT WILL REMAIN UNSETTLED ACROSS THE AREA TUESDAY THROUGH THE END
OF THE WEEK WITH A CHANCE FOR MORE THUNDERSTORMS ACROSS MOST OF
THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL LIKELY BE NEEDED ACROSS THE AREA LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TOPEKA KS
1119 AM CDT SUN JUN 07 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1100 PM     HAIL             5 E BARNES              39.71N 96.78W
06/06/2009  E1.00 INCH       MARSHALL           KS   TRAINED SPOTTER

            WINDOWS BROKEN AT NEARBY HOME BECAUSE OF WIND DRIVEN
            HAILSTONES. DELAYED REPORT.

&&

MRC

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
400 PM CDT SUN JUN 7 2009

KSZ011-012-072230-
BROWN-NEMAHA-
400 PM CDT SUN JUN 7 2009

...SIGNIFICANT WEATHER ALERT FOR NEMAHA AND BROWN COUNTIES...

THROUGH 530 PM CDT...A THUNDERSTORM WILL MOVE NORTHEAST AT 25 MPH
ACROSS PORTIONS OF NORTHEAST NEMAHA AND NORTHWEST BROWN COUNTIES.
NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THIS STORM IS
CAPABLE OF PRODUCING NICKEL SIZE HAIL. SOME LOCATIONS THAT COULD BE
AFFECTED INCLUDE SABETHA...FAIRVIEW...MORRILL...HAMLIN AND RESERVE.

A TORNADO WATCH IS ALSO IN EFFECT. THE STORM MAY STRENGTHEN OVER THE
NEXT SEVERAL MINUTES. BE READY TO TAKE SHELTER IN CASE A WARNING IS
ISSUED.