Special Weather Statement, NWS Topeka, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
306 PM CDT THU MAY 19 2011

.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...

AS OF MID AFTERNOON THURSDAY...A WARM FRONT EXTENDED FROM NEAR GREAT
BEND THROUGH PARSONS KANSAS AND WAS STEADILY LIFTING NORTHWARD IN
RESPONSE TO PRESSURE FALLS AND GRADUALLY CLEARING SKIES IMMEDIATELY
NORTH OF THE FRONT. A RATHER SHARP DRY LINE WAS EVIDENT ON SATELLITE
FROM NEAR HAYS KANSAS TO GAGE OKLAHOMA. THUNDERSTORMS HAD ALREADY
DEVELOPED OVER OKLAHOMA ALONG THE DRY LINE IN RESPONSE TO AN
ADVANCING SHORT WAVE TROUGH WITH THE EXPECTATION THAT THE TROUGH
WOULD INDUCE CONVECTIVE DEVELOPMENT INTO THE WARM SECTOR OVER
CENTRAL KANSAS PRIOR TO 21Z. THE WARM SECTOR OF THE SYSTEM WAS
RATHER UNSTABLE WITH LITTLE TO NO CAP AND STRONG DEEP LAYER SHEAR.
THIS WOULD BE A FAVORABLE ENVIRONMENT FOR DEVELOPMENT OF SUPERCELL
THUNDERSTORMS CAPABLE OF LARGE HAIL AND DAMAGING WINDS. LOW LEVEL
SHEAR AND MOISTURE PROFILES WERE ALSO SUPPORTIVE OF A TORNADO THREAT
IN THE WARM SECTOR AND NEAR/JUST NORTH OF THE WARM FRONT. NEAR TERM
HIGH RESOLUTION MODELS SUGGEST AT LEAST SOME POTENTIAL FOR
DEVELOPMENT WELL AHEAD OF THE DRY LINE...AND WHILE THIS APPEARS
POSSIBLE...THE AREA WITH THE GREATEST SEVERE THREAT WILL REMAIN WEST
OF A BELLEVILLE TO COUNCIL GROVE LINE THROUGH THE EVENING FOR THOSE
STORMS DEVELOPING ALONG THE DRY LINE AND MOVING NORTHEAST TO
INTERACT WITH THE SHALLOW WARM FRONT.

THE INITIAL WAVE OF CONVECTION OVER CENTRAL OKLAHOMA AND KANSAS WILL
LIKELY DEVELOP INTO ONE OR MORE CONVECTIVE COMPLEXES OVERNIGHT AND
SLOWLY MAKE ITS WAY ACROSS THE FORECAST AREA. MEANWHILE...ADDITIONAL
DEVELOPMENT IS POSSIBLE IN WESTERN AND CENTRAL KANSAS AGAIN
OVERNIGHT...WHICH WOULD ALSO EVENTUALLY MOVE INTO THE LOCAL FORECAST
AREA. THE TORNADO THREAT APPEARS TO QUICKLY WANE AFTER MID EVENING
BUT HAIL AND DAMAGING WINDS WILL REMAIN POSSIBLE ACROSS THE AREA
WITH OVERNIGHT CONVECTION. VERY HEAVY RAIN AND SOME FLOODING ISSUES
APPEAR TO BE A THREAT OVERNIGHT AS WELL GIVEN HIGH ENVIRONMENTAL
MOISTURE CONTENT AND SOME TRAINING POTENTIAL...PARTICULARLY IN
AREAS THAT RECEIVED SIGNIFICANT RAINFALL WEDNESDAY NIGHT.

AFTER MORNING CONVECTION...EXPECT REDEVELOPMENT OF STORMS FRIDAY
AFTERNOON AS THE WARM FRONT WILL REMAIN DRAPED ACROSS THE AREA AND
THE DRY LINE IS FORECAST TO SURGE A BIT INTO SOUTH CENTRAL KANSAS.
MODERATE INSTABILITY WILL BE PRESENT WITH 35 TO 40 KTS OF DEEP LAYER
SHEAR EXPECTED TO BE SUFFICIENT ONCE AGAIN FOR EMBEDDED SUPERCELL
DEVELOPMENT. ALL MODES OF SEVERE WEATHER APPEAR POSSIBLE DURING THE
AFTERNOON AND EVENING HOURS...ONCE AGAIN WITH AN ENHANCED FLOODING
POTENTIAL GIVEN MULTIPLE ROUNDS OF THUNDERSTORMS EXPECTED.

BARJENBRUCH

&&

.LONG TERM (SATURDAY THROUGH THURSDAY)...

FOR THE NEXT SEVERAL DAYS CHANCES FOR THUNDERSTORMS WILL CONTINUE AS
MODELS INDICATE NUMEROUS SHORTWAVE TROUGHS THAT WILL KEEP THE
WEATHER ACTIVE OVER THE CENTRAL UNITED STATES. ON SATURDAY MODELS
INDICATE THAT THE MAIN UPPER LEVEL TROUGH WILL MOVE THROUGH THE CWA.
UPPER LEVEL DIVERGENCE ALONG WITH WARM AIR ADVECTION AND AMPLE
INSTABILITY SHOULD KEEP CHANCES FOR STRONG TO SEVERE STORMS
CONTINUING INTO SATURDAY. MODELS AGREE THAT THE UPPER LEVEL TROUGH
WILL MOVE THE NORTH AND EAST OF THE CWA. A BRIEF LULL IN
THUNDERSTORM ACTIVITY IS ANTICIPATED SUNDAY MORNING JUST BEFORE THE
NEXT SHORTWAVE ARRIVES SUNDAY AFTERNOON AND EVENING.

EARLY NEXT WEEK THE GFS AND EC SHOW A NUMBER OF SHORTWAVES THAT MOVE
THROUGH BUT DIFFER SLIGHTLY ON THE TIMING AND STRENGTH. BOTH AGREE A
SHORTWAVE TROUGH WILL MOVE THROUGH THE CENTRAL PLAINS AND LEAD TO
LEE CYCLOGENESIS ON MONDAY AND BRING A ROUND OF THUNDERSTORMS TO THE
AREA BUT DIFFER ON THE LOCATION OF THE LOW. THE GFS WANTS TO BRING A
FRONT THROUGH THE REGION ON TUESDAY AS A MORE IMPRESSIVE SHORTWAVE
PASSES TO THE SOUTH OF THE CWA ON WEDNESDAY. THE EC WANTS TO PUSH
THE SYSTEM THROUGH BUT BRINGS RETURN FLOW AND WARM AIR ADVECTION
BACK QUICKLY TO THE CENTRAL UNITED STATES. THE EC ALSO BRINGS AN
IMPRESSIVE SHORTWAVE ACROSS THE CENTRAL PLAINS THAT WOULD BE
FAVORABLE FOR SEVERE WEATHER ACROSS THE CWA. HAVE SIDED MORE WITH
THE EC IN THE FORECAST DUE TO ACTIVE PATTERN THAT THE CWA IS IN.

ANDERSON

&&

.AVIATION...

A VERY COMPLICATED TAF WILL START OFF WITH WIDESPREAD CIGS IN THE
900 TO 1100 FT RANGE. HAVE ALSO SEEN SCT TO BKN IFR CIG NEAR TOP
AND FOE SO HAVE IFR FORECAST FOR AT LEAST A BIT THIS AFTERNOON.
CLOUDS BREAKING UP TO THE SOUTH AND MAY SEE BKN MVFR LATE
AFTERNOON AND EARLY EVENING. TS EXPECTED TO IMPACT ALL TAF SITES
DURING THE EVENING AND OVERNIGHT WITH LITTLE CONFIDENCE IN EXACT
TS TIMING. DO FEEL TS WILL HOLD OFF AFTER 00Z AND WILL MOVE OUT
BY 09Z TO 14Z WITH IFR CIGS THROUGH THE REST OF THE TAF PERIOD.

BARJENBRUCH

&&

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

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TOPEKA KS
314 PM CDT THU MAY 19 2011

KSZ008>012-020>024-026-034>040-054>056-058-059-202015-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
314 PM CDT THU MAY 19 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THUNDERSTORMS DEVELOPING IN CENTRAL KANSAS THIS AFTERNOON WILL
TRACK NORTHEAST AND MAY AFFECT AREAS WEST OF A BELLEVILLE TO CLAY
CENTER TO COUNCIL GROVE LINE DURING THE EVENING HOURS. THESE
STORMS WILL BE CAPABLE OF PRODUCING TORNADOES...HAIL UP TO THE
SIZE OF GOLF BALLS AND WINDS UP TO 70 MPH.

THUNDERSTORMS WILL MERGE INTO A COMPLEX OF THUNDERSTORMS
OVERNIGHT AND MOVE ACROSS NORTH CENTRAL...NORTHEAST AND EAST
CENTRAL KANSAS. HAIL UP TO THE SIZE OF QUARTERS...GUSTY WINDS UP
TO 60 MPH AND HEAVY RAIN ALONG WITH LOCALIZED FLASH FLOODING WILL
BE POSSIBLE WITH THESE THUNDERSTORMS TONIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

ADDITIONAL THUNDERSTORMS ARE LIKELY FRIDAY AND FRIDAY NIGHT...
WITH SOME POTENTIAL FOR SEVERE STORMS ONCE AGAIN. WHILE DAMAGING
WIND...LARGE HAIL...AND LOCALIZED FLOODING WILL BE THE GREATEST
THREATS...THERE WILL BE A LOW END POTENTIAL FOR TORNADOES NEAR
AND SOUTH OF INTERSTATE 70 DURING THE LATE AFTERNOON AND EVENING
HOURS.

THUNDERSTORM CHANCES CONTINUE THROUGH MUCH OF THE WEEKEND AND
NEXT WEEK. FLOODING POTENTIAL WILL INCREASE THROUGH EARLY NEXT
WEEK GIVEN THE POTENTIAL FOR MULTIPLE ROUNDS OF THUNDERSTORMS AND
ABUNDANT MOISTURE IN THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THROUGH 9 PM NEAR AND WEST OF A
LINE FROM NEAR BELLEVILLE...TO CLAY CENTER TO COUNCIL GROVE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
705 PM CDT THU MAY 19 2011

KSZ008-009-200030-
REPUBLIC-WASHINGTON-
705 PM CDT THU MAY 19 2011

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN REPUBLIC AND NORTHWESTERN
WASHINGTON COUNTIES...

THROUGH 730 PM CDT...A THUNDERSTORM WILL MOVE NORTH AT 55 MPH ACROSS
PORTIONS OF EASTERN REPUBLIC AND NORTHWESTERN WASHINGTON COUNTIES.
NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THIS STORM IS
CAPABLE OF PRODUCING NICKEL SIZE HAIL AND TORRENTIAL RAINFALL. SOME
LOCATIONS THAT COULD BE AFFECTED INCLUDE CUBA...MUNDEN...NARKA AND
MAHASKA.

A TORNADO WATCH IS ALSO IN EFFECT. STAY ALERT TO THE WEATHER IN CASE
A WARNING IS ISSUED.

&&

LAT...LON 4001 9721 3965 9746 3965 9755 3969 9769
      4001 9762
TIME...MOT...LOC 0005Z 201DEG 47KT 3975 9754