Flood and Hail in Kansas, February 27, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
313 PM CST SUN FEB 27 2011

.DISCUSSION...

TONIGHT AND TOMORROW...

WATER VAPOR AND RUC ANALYSIS SHOWS A NEUTRAL TO SLIGHTLY POSITIVE
TILT TROUGH EJECTING INTO THE CENTRAL PLAINS FROM THE INTERIOR
WESTERN STATES. LARGE SCALE SOUTHWESTERLY FLOW AHEAD OF THE
ADVANCING TROUGH. AT THE SURFACE A WARM FRONT HAS PRESSED
NORTHWARD AND IS CURRENTLY DRAPED ON A LINE FROM KICT TO GARNETT.
NORTH OF THIS WARM FRONT COOL AIR IN PLACE WILL ALLOW THE MID
LEVEL WARM AIR TO RIDE OVER THE TOP ISENTROPICALLY. AN ELEVATED
MIXED LAYER AROUND 850 MB WILL PROVIDE THE NECESSARY ELEVATED
INSTABILITY TO INITIATE THUNDERSTORMS. GIVEN THE MIXED LAYER
INSTABILITY OF AROUND 500 TO 700 J/KG ENOUGH INSTABILITY IS
PRESENT TO ALLOW FOR TALL ELEVATED THUNDERSTORMS. EFFECTIVE SHEAR
PARAMETERS ALSO INDICATE THE POSSIBILITY OF ROTATING STORMS AS
EFFECTIVE BULK SHEAR LOOKS TO BE IN THE 30 TO 40 KT RANGE. THE 12Z
KTOP SOUNDING INDICATED A VERY DRY LAYER OF AIR ABOVE 850MB...BUT
850 MOISTURE HAS BEEN SLOWLY WORKING ITS WAY INTO THE COLUMN.

RADAR TRENDS CONTINUE TO INDICATE SHOWERS AND THUNDERSTORMS
CONTINUING TO SPREAD IN COVERAGE AND INCREASE IN INTENSITY. EXPECT
STORMS TO CONTINUE TO THE NORTHEAST AROUND 40 KNOTS. STILL EXPECT
THE MAIN AREA OF SEVERE WEATHER TO REMAIN ALONG AND SOUTHEAST OF THE
KANSAS TURNPIKE...HOWEVER COUNTIES ALONG OR JUST NORTHWEST OF THE
TURNPIKE COULD SEE SOME STORMS BECOME SEVERE THIS AFTERNOON/EVENING.
THE MAIN THREAT FROM THESE STORMS WILL BE HAIL...AS SURFACE
TEMPERATURES REMAIN RATHER COOL AND UNDER FOG/STRATUS. THESE COOL
CONDITIONS AT THE SURFACE WILL ALLOW THE INVERSION TO PERSIST...THUS
CUTTING OF THE ELEVATED MIXED UNSTABLE LAYER FROM THE SURFACE. AS A
RESULT...DO NOT EXPECT CONVECTIVE WINDS NOR TORNADOES TO BE MUCH OF
A THREAT.  THE ONLY REAL THREAT FOR SURFACE BASED STORMS SHOULD
REMAIN SOUTH OF INTERSTATE 35...OR EVEN FURTHER SOUTH.

ASIDE FROM THE CONVECTIVE POTENTIAL FOR THE REMAINDER OF THE
AFTERNOON/EVENING...EXPECT DENSE FOG TO CONTINUE IN PORTIONS SOUTH
OF THE ADVANCING COLD FRONT ACROSS NORTHEAST KANSAS AND NORTH OF THE
NOW NEARLY STATIONARY WARM FRONT ALONG INTERSTATE 35. THESE FOGGY
CONDITIONS WILL CAUSE VISIBILITIES TO REMAIN AT OR BELOW A HALF MILE
UNTIL RAIN SHOWERS CAN HELP CLEAR THE BOUNDARY LAYER OUT.

AS THE COLD FRONT ADVANCES...TEMPERATURES AT THE SURFACE AND IN THE
MIDLEVELS WILL COOL ADEQUATELY TO CHANGE ANY LINGERING RAIN SHOWERS
INTO A GRADUAL TRANSITION OF FREEZING RAIN AND EVENTUALLY SNOW. THE
AMOUNT OF MOISTURE THAT CAN WRAP ITSELF BACK AROUND THE SURFACE LOW
LOOKS TO BE RATHER MODEST...THEREFORE DO NOT EXPECT MUCH
ACCUMULATION OF FREEZING PRECIPITATION. OVERNIGHT SUNDAY NIGHT
INTO MONDAY.  JL

MADE VERY LITTLE CHANGE TO EXTENDED FORECAST WITH ONGOING CURRENT
CONDITIONS. PATTERN REMAINS ACTIVE WITH WARMER TEMPS TUESDAY AND
THURSDAY WITH FRONTAL INTRUSIONS WEDNESDAY AND LATE FRIDAY. 67

&&

.AVIATION...

FOR 18Z TAFS...LIFR CONDITIONS EXPECTED FOR KTOP/KFOE/KMHK THROUGH
LATE AFTERNOON AS WARM FRONT TO THE SOUTH WILL KEEP ADEQUATE
MOISTURE AND FOG IN PLACE. AS FRONTAL BOUNDARY MIGRATES SLOWLY
NORTHWARD...CIGS IMPROVE TO IFR WITH SHOWERS AND ISOLATED TSRA
POSSIBLE AFTER 20Z. UNCERTAINTY EXISTS ON EXACT TIMING AND
LOCATION OF CONVECTION THAT DEVELOPS. A SOUTHWARD MOVING COLD
FRONT WILL SHIFT OVER TERMINALS AFTER 05Z FOR KMHK AND 07Z FOR
KTOP/KFOE WITH ONLY AN INCREASE IN NORTH WINDS OVER 10 KTS. AS
HIGH PRESSURE SETTLES OVERHEAD...GRADUALLY BROUGHT UP CIGS AND VIS
TO MVFR AND THEN VFR SHORTLY AFTER SUNRISE.

BOWEN

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR KSZ011-012-
021>024-026-034>040-054-055.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
1253 PM CST SUN FEB 27 2011

KSZ008>012-020>024-026-034>040-054>056-058-059-281900-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
1253 PM CST SUN FEB 27 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

AREAS OF DENSE FOG WILL CONTINUE ACROSS MOST OF THE OUTLOOK AREA
THIS AFTERNOON REDUCING VISIBILITIES TO LESS THAN A QUARTER OF A
MILE IN SOME AREAS. AREAS OF NORTHEAST KANSAS WILL CONTINUE TO SEE
DENSE FOG...WHILE NORTH CENTRAL AND EAST CENTRAL KANSAS WILL SEE
IMPROVING CONDITIONS.

THERE IS A CHANCE FOR THUNDERSTORMS ACROSS EAST CENTRAL AND
NORTHEAST KANSAS THIS AFTERNOON AND EVENING. SOME OF THESE STORMS
COULD BE STRONG TO SEVERE WITH QUARTER SIZED HAIL BEING THE
PRIMARY THREAT...MAINLY SOUTH AND EAST OF THE KANSAS TURNPIKE.
LOCALLY HEAVY RAINFALL IS POSSIBLE WITH THUNDERSTORMS OVER THIS
AREA. AS A RESULT...LOCALIZED FLOODING IS POSSIBLE AS THE GROUND
IS SATURATED AND OR FROZEN WHICH WOULD LEAD TO RAPID RUNOFF OF ANY
RAINFALL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS MAY BE NEEDED THIS AFTERNOON OR TONIGHT MAINLY SOUTH AND
EAST OF INTERSTATE 35. SPOTTERS ARE ENCOURAGED TO REPORT HAIL
SIZES AND FLASH FLOODING CONDITIONS.