Flash Flood Warning 10, NWS Topeka, KS

AREA FORECAST DISCUSSION...CORRECTED DATE/TIME AND WWA SECTION
NATIONAL WEATHER SERVICE TOPEKA KS
327 AM CDT WED OCT 17 2007

.DISCUSSION...
WAA AND ISENTROPIC LIFT HAVE COMBINED TO CREATE ELEVATED
THUNDERSTORMS ACROSS CENTRAL KS THIS MORNING. 08Z WATER VAPOR
IMAGERY SHOWS MID LEVEL TROUGH AXIS ROTATING THROUGH THE SOUTHERN
ROCKIES WITH AN INITIAL SHORTWAVE LIFTING THROUGH THE TX PANHANDLE.
AT THE SFC...MOISTURE RETURN IS IN FULL SWING WITH 60 DEGREE
DEWPOINTS ALREADY IN SOUTHERN KS.

AS SYNOPTIC SCALE FORCING CONTINUES TO OVERSPREAD THE FORECAST AREA
THIS MORNING...ELEVATED CONVECTION WILL EXPAND IN COVERAGE. ALREADY
GETTING SOME REPORTS OF SMALL HAIL WITH THESE ELEVATED THUNDERSTORMS
AND ANTICIPATE THE POTENTIAL FOR MARGINAL HAIL TO BE THE MAIN
CONCERN WITH THESE ELEVATED STORMS. 00Z MODELS THIS MORNING SHOW
LITTLE CHANGE FROM PREVIOUS FORECAST IDEAS AND HAVE NOT MADE A LOT
OF CHANGES. MAIN CONCERN WITH SEVERE POTENTIAL WILL BE ALONG THE
DRYLINE ACROSS SOUTH CENTRAL KS. IF THE SUN IS ABLE TO BREAK OUT
ALONG THE DRYLINE THIS AFTERNOON...SHEER AND INSTABILITY WILL LINE
UP ALONG AND AHEAD OF THE DRYLINE JUST AS THE NEGATIVE TROUGH SWINGS
THROUGH PROVIDING THE BEST FORCING. STORMS ROOTED IN THE BOUNDARY
LAYER ARE EXPECTED TO BE SUPERCELLULAR. GIVEN THE AMOUNT OF SHEER
AND LOW LCL AND LFC HEIGHTS...SOME OF THESE STORMS COULD PRODUCE A
FEW TORNADOES. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR THIS TO
OCCUR WILL BE MAINLY SOUTH OF THE FORECAST AREA WITH OVERCAST
CONDITIONS PERSISTING OVER NORTH CENTRAL AND NORTHEAST KS LIMITING
INSTABILITY. HOWEVER WILL NEED TO WATCH STORM INITIATION AS STORMS
THAT FORM IN SOUTH CENTRAL KS COULD MOVE INTO EAST CENTRAL KS.

FLOODING IS ALSO A CONCERN FOR THIS AFTERNOON AND THIS EVENING.
MODELS SHOW PWS INCREASING TO BETWEEN 1.5 AND 2 INCHES. WITH THE
POTENTIAL FOR A COUPLE ROUNDS OF PRECIP /ELEVATED TS THIS MORNING
THEN MORE ORGANIZED CONVECTION WITH HEAVY RAIN THIS AFTERNOON AND
EVENING/ AND ONE HOUR FLASH FLOOD GUIDANCE AROUND AN INCH OR
LESS...HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS WEST OF MHK AND
NORTH OF OTTAWA. LEFT NORTH CENTRAL KS OUT OF THE WATCH FOR NOW WITH
LARGER STORM TOTAL AMOUNTS EXPECTED TO BE HIGHEST ACROSS NORTHEAST
KS. ALSO LEFT LYON...COFFEE AND ANDERSON COUNTIES OUT SINCE THEY DOD
NOT RECEIVE NEARLY AS MUCH RAIN IN RECENT DAYS AND FFG VALUES ARE
SOMEWHAT HIGHER.

CONTINUED WITH POPS FOR THURSDAY AS MODELS SHOW WRAP AROUND MOISTURE
MOVING ACROSS THE AREA WITH PRECIP DEVELOPING. GFS FORECAST
SOUNDINGS INDICATE SOME STEP LAPSE RATES EARLY IN THE DAY MOVING
EAST INTO MO BY THE AFTERNOON. WHILE THINK THERE WILL BE MORE
SHOWERS THAN ANYTHING...INCLUDED A MENTION OF THUNDER DUE TO THESE
LAPSE RATES. WINDY CONDITIONS STILL LOOK PLAUSIBLE AS THE SFC LOW
OVER IA. CLOUD COVER AND CAA SHOULD LIMIT MUCH OF A WARM UP ON
THURSDAY AND PREVIOUS FORECAST SHOWS THIS WELL.

DID NOT MAKE ANY CHANGES TO THE FORECAST BEYOND FRIDAY.

&&

WOLTERS

.AVIATION...
AVIATION CONCERNS WILL BE MVFR CIGS AND VSBY WITH SCATTERED
THUNDERSTORMS. BUFKIT SOUNDINGS INDICATE TRENDS COULD BE IFR FOR A
TIME IN THE MORNING AND WILL INCLUDE WITH TEMPO GROUPS FOR
CONVECTION. CLOSER TO 12Z TAF ISSUANCE MAY GO WITH PREVAILING IFR
CIGS THROUGH MID MORNING. HAVE SOME GUSTINESS AT THE SURFACE BUT
GIVEN PROFILERS SHOWING 50KTS AT LOWER GATES...WILL STILL KEEP LOW
LEVEL WIND SHEAR IN TAFS THROUGH ABOUT 15Z. WILL HAVE PREVAILING TS
WITH TEMPO IFR CIGS/VSBY INCLUDING SOME POTENTIAL FOR HAIL...GUSTY
WINDS AND HEAVY RAINFALL THROUGH THE AFTERNOON HOURS. AFTER 06Z
SURFACE WINDS TURNING MORE SOUTHWESTERLY AND EXPECT A DECREASE IN TS
COVERAGE WITH PREVAILING CEILINGS BECOMING VFR OUTSIDE OF
PRECIPITATION CHANCES.

&&

FRANTZ

.TOP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH NORTH AND WEST OF A MELVERN TO JUNCTION CITY TO
MARYSVILLE LINE FROM 10 AM TODAY UNTIL 1 AM THURSDAY.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
514 AM CDT WED OCT 17 2007

KSZ008>012-020>024-026-034>040-054>056-058-059-181015-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
514 AM CDT WED OCT 17 2007

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

.DAY ONE...TODAY AND TONIGHT

SEVERE THUNDERSTORMS ARE POSSIBLE THROUGH THE DAY TODAY AND THIS
EVENING. INITIALLY THUNDERSTORMS WILL MOVE NORTHEAST ACROSS NORTH
CENTRAL...NORTHEAST AND EAST CENTRAL KANSAS THIS MORNING AND
INCREASE IN COVERAGE. THESE STORMS COULD PRODUCE HAIL AROUND ONE
INCH IN DIAMETER AND WIND GUSTS AROUND 60 MPH THROUGH MID MORNING.
THERE COULD BE A BREAK IN THE THUNDERSTORM ACTIVITY BEFORE
ADDITIONAL THUNDERSTORMS DEVELOP ALONG A DRY LINE ACROSS CENTRAL
KANSAS DURING THE AFTERNOON. THESE STORMS WILL HAVE THE POTENTIAL FOR
PRODUCING HAIL LARGER THAN AN INCH IN DIAMETER...DAMAGING STRAIGHT
LINE WINDS AND AN ISOLATED TORNADO OR TWO. WHILE THE HAIL AND
WINDS COULD OCCUR ANYWHERE IN THE OUTLOOK AREA...THE TORNADO
HAZARD APPEARS TO BE GREATEST SOUTH OF INTERSTATE 70 DURING THE
AFTERNOON AND EARLY EVENING.

ADDITIONALLY HEAVY RAIN WILL OCCUR WITH THE THUNDERSTORMS THROUGH
THE DAY. THIS COULD CREATE A FLASH FLOODING HAZARD ACROSS
NORTHEAST AND PARTS OF EAST CENTRAL KANSAS...AND A FLASH FLOOD
WATCH HAS BEEN ISSUED.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

AN ISOLATED THUNDERSTORM IS POSSIBLE DURING THE DAY THURSDAY.
THUNDERSTORMS RETURN TO THE FORECAST ACROSS NORTH CENTRAL KANSAS
SUNDAY...SPREADING INTO NORTHEAST AND EAST CENTRAL KANSAS SUNDAY
NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL LIKELY BE NEEDED THIS AFTERNOON AND THIS EVENING.

WOLTERS