Flash Flood and Damaging Wind in Kansas, June 7, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
338 PM CDT THU JUN 7 2007

.DISCUSSION...

IMMEDIATE FORECAST CONCERNS ARE SEVERE THUNDERSTORMS THROUGH THIS
EVENING AND THEN THUNDERSTORM CHANCES AGAIN THIS WEEKEND INTO NEXT
WEEK.

TONIGHT...TORNADO WATCH WILL REMAIN IN EFFECT THIS EVENING ACROSS
EAST CENTRAL KS UNTIL THE DRYLINE MOVES THROUGH.  VERY STRONG WIND
SHEAR AND SUFFICIENT INSTABILITY IN FRONT OF THE DRYLINE PROMPTED
THE TORNADO WATCH THROUGH THE EVENING HOURS.  THUNDERSTORMS HAD
ALREADY DEVELOPED ALONG THE WESTERN EDGE OF THE WATCH BOX AT
FORECAST TIME.  SUPERCELLS AND ORGANIZED LINE SEGMENTED
THUNDERSTORMS ARE POSSIBLE.  SEE THE LATEST HAZARDOUS WEATHER
OUTLOOK OR THE LATEST WATCHES AND WARNINGS IN THE CWA FOR THE LATEST
SEVERE WEATHER UPDATE.

THE DRYLINE/FRONTAL BOUNDARY IS EXPECTED TO MOVE THROUGH THE ENTIRE
FORECAST AREA THIS EVENING...SHORTLY AFTER 10 PM.  BEHIND THE
DRYLINE/FRONTAL BOUNDARY DEWPOINT VALUES HAVE FALLEN OFF SHARPLY AND
CONDITIONS BEHIND THE BOUNDARY HAVE APPROACHED RED FLAG WARNING
CRITERIA WITH RELATIVE HUMIDITY VALUES FALLING BELOW 20 PERCENT AND
WIND GUSTS ABOVE 25 MPH.  BECAUSE THE AREA FOLIAGE IS VERY GREEN AT
THIS TIME...AND THE GROUND IS RELATIVELY MOIST NO COUNTIES IN THE
FORECAST AREA INDICATED CRITICAL FUELS FOR FIRE DANGER THUS NO RED
FLAG WARNING WAS ISSUED FOR THE REMAINDER OF THE AFTERNOON HOURS.
SKIES WILL REMAIN MOSTLY CLEAR BEHIND THE DRYLINE UNTIL A SECONDARY
SURGE OF COOLER AIR WORKS SOUTH THROUGH THE CENTRAL PLAINS.  THE
BOUNDARY OF THIS SECONDARY SURGE WAS CURRENTLY OVER WESTERN NE
PUSHING SOUTHEAST.  TIMING OF THIS BOUNDARY WOULD BRING IT INTO
NORTH CENTRAL KS AROUND 06Z AND THEN THROUGH EAST CENTRAL KS BY
12Z.  FORECAST SOUNDINGS INDICATE THAT A DECK OF STRATA CUMULUS WILL
DEVELOP OVER THE AREA OVERNIGHT.  BETWEEN THE DRIER AIR...AT LEAST
PART OF THE NIGHT WITH MOSTLY CLEAR SKIES AND THE SECONDARY SURGE OF
COLD AIR OVERNIGHT EXPECT LOWS TO FALL INTO THE LOWER TO MID 50S
ACROSS THE CWA.

TOMORROW...HIGH PRESSURE BEHIND THIS SECONDARY BOUNDARY WILL SETTLE
IN OVER NORTHEAST KANSAS ALLOWING FOR FAIR WEATHER AND MOSTLY SUNNY
SKIES.  THICKNESS VALUES INDICATE HIGHS IN THE MID 70S FOR MOST
LOCATIONS...BUT BUMPED TEMPS INTO THE UPPER 70S ACROSS NORTH CENTRAL
KS WHICH HAS A CHANCE TO CATCH SOME RETURN SOUTHERLY FLOW ON THE
BACKSIDE OF THE SURFACE HIGH BEFORE SUNSET.

SURFACE HIGH WILL MOVE SLOWLY EAST INTO MISSOURI WITH RETURN FLOW
BEGINNING NEAR 12Z SATURDAY. WITH LIGHT WINDS AND MOSTLY CLEAR SKIES
EXPECT MORNING LOWS IN THE LOWER TO MID 50S.

MOISTURE WILL MOVE NORTH INTO EASTERN KANSAS DURING THE DAY SATURDAY
WITH DEW POINTS IN THE LOW TO MID 60S EXPECTED BY 00Z SUNDAY.
THUNDERSTORMS ARE LIKELY TO DEVELOP SATURDAY EVENING ACROSS THE
WESTERN PLAINS...THEN IN WAA REGIME ACROSS NORTHEAST KANSAS AHEAD OF
A MID LEVEL TROUGH MOVING ACROSS NORTH CENTRAL KANSAS. THINK BEST
CHANCES WILL BE AFTER 06Z SUNDAY.

ON SUNDAY A SHORTWAVE WILL MOVE ACROSS THE STATE IN MOISTURE RICH
AND UNSTABLE ENVIRONMENT. POTENTIAL WILL EXIST FOR SOME SEVERE
STORMS SUNDAY ALONG WITH LOCALLY HEAVY RAINFALL.

FOR THE EXTENDED MONDAY THROUGH THURSDAY LEANED TOWARD THE CONSENSUS
OF USING THE ECMWF AND THE GFS ENSEMBLE MEAN FOR THE FORECAST. LEE
TROUGH WILL REMAIN ESTABLISHED ACROSS THE WESTERN PLAINS WITH
SOUTHWEST FLOW AT 500 MB WITH OCCASIONAL SHORTWAVES MOVING OVER THE
TOP OF THE SOUTHERN PLAINS RIDGE. UPPER TROUGH MOVES THROUGH IN THE
WEDNESDAY NIGHT EARLY THURSDAY TIME PERIOD. SO EXPECT OFF AND ON
PRECIPITATION MAINLY AT NIGHT AND LATE AFTERNOON THROUGH THE
MAJORITY OF THE WEEK. RIDGE BEGINS TO BUILD INTO FRIDAY SO WEEKS END
LOOKS LIKE IT SHOULD BE DRY. HIGHS IN THE 80S TO NEAR 90 WITH LOWS
IN THE 60S. PERIOD WILL ALSO BE A BIT ON THE HUMID SIDE THROUGH THE
MIDDLE OF THE WEEK.

&&

.AVIATION...
ALL TAF SITES ARE ALREADY BEHIND THE DRYLINE SO THE NEXT 24 HOURS
ARE RELATIVELY QUIET IN TERMS OF AVIATION WEATHER.  GUSTY WESTERLY
WINDS WILL VEER AROUND TO THE NORTH OVERNIGHT WITH THE PASSAGE OF A
SECONDARY COLD AIR BOUNDARY.  WITH THE PASSAGE OF THIS SECONDARY
BOUNDARY A DECK OF SCATTERED STRATA CUMULUS.  THIS DECK IS EXPECTED
TO BE RIGHT AROUND THE MVFR LEVEL...SO WILL HAVE TO MONITOR FOR
POSSIBLE BROKEN MVFR DECK OVERNIGHT...BUT CURRENT FORECAST SOUNDINGS
INDICATE THE PROFILE IS PRETTY DRY AT THE TIME OF THE BOUNDARY
PASSAGE...SO WAS NOT CONVINCED IN A CEILING DEVELOPING.  AS HIGH
PRESSURE MOVES IN BEHIND THE BOUNDARY WINDS WILL BECOME LIGHT AND
VARIABLE TOMORROW AFTERNOON AND ANY REMAINING CU DECK IS EXPECTED TO
DISSIPATE.

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
406 PM CDT THU JUN 7 2007

KSZ008>012-020>024-026-034>040-054>056-058-059-082115-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
406 PM CDT THU JUN 7 2007

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

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS WILL CONTINUE THIS EVENING MAINLY ALONG
AND SOUTH OF A LAWRENCE TO EMPORIA LINE. SOME OF THE STORMS MAY BE
SEVERE WITH LARGE HAIL...DAMAGING WINDS AND POSSIBLY TORNADOES.
ALSO VERY HEAVY RAINFALL MAY CAUSE FLASH FLOODING OF LOW LYING
AREAS AND SMALL CREEKS ACROSS EAST CENTRAL KANSAS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORM CHANCES RETURN TO THE AREA SATURDAY NIGHT THROUGH
WEDNESDAY. AT THIS TIME IT APPEARS THAT SOME OF THE STORMS
COULD BE SEVERE ON SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL BE NEEDED TONIGHT ALONG AND SOUTH OF A LAWRENCE TO
EMPORIA LINE. ALSO...SPOTTERS ARE ENCOURAGED TO REPORT RAINFALL AMOUNTS
OVER ONE INCH TO THE NATIONAL WEATHER SERVICE IN TOPEKA.

SIGNIFICANT WEATHER ALERT
NATIONAL WEATHER SERVICE TOPEKA KS
245 PM CDT THU JUN 7 2007

KSZ040-072015-
DOUGLAS-
245 PM CDT THU JUN 7 2007

THROUGH 315 PM CDT...A THUNDERSTORM WILL MOVE NORTHEAST AT 50 MPH
ACROSS PORTIONS OF DOUGLAS COUNTY. NATIONAL WEATHER SERVICE DOPPLER
RADAR INDICATED THIS STORM IS CAPABLE OF PRODUCING PENNY SIZE HAIL...
STRONG WINDS OF 40 TO 50 MPH AND HEAVY RAIN. SOME COMMUNITIES THAT
COULD BE AFFECTED INCLUDE LONE STAR...PLEASANT GROVE...CLINTON STATE
PARK...VINLAND...SOUTHERN LAWRENCE AND EUDORA.

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