High Wind and Strong Wind in Kansas, March 23, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1044 AM CDT MON MAR 23 2009

.UPDATE...

UPDATED FOR SHORT TERM FORECAST.

&&

.DISCUSSION...

...MESOSCALE UPDATE...

RAN A QUICK FORECAST UPDATE TO UPGRADE TO A HIGH WIND WARNING
ACROSS MUCH OF NORTH CENTRAL AND PORTIONS OF NORTHEAST KANSAS FOR
LATE THIS MORNING THROUGH THIS EVENING. WIND GUSTS IN THE 55 TO 60
MPH RANGE LOOK LIKELY ACROSS THIS AREA THROUGH 7 PM CDT. DECIDED
TO NOT GO FURTHER EAST WITH THE WARNING AT THIS TIME AS BREAKS IN
THE STRATA CU DECK AND PRESSURE FALLS OF AROUND 1 MB PER HOUR ARE
CENTERED OVER NORTHWEST KS AND SOUTHWESTERN NE. WITH DEEPER MIXING
DUE TO BETTER SOLAR INSOLATION OVER THE WESTERN CWA...AND WITH THE
PRESSURE GRADIENT TIGHTENING OVER WESTERN KS...THOUGHT THIS WAS
THE MOST LIKELY THREAT AREA IN THE SHORT TERM. WILL CONTINUE TO
WATCH THE EVOLUTION OF THIS DYNAMIC SYSTEM AND UPGRADE HIGH WIND
WARNING EAST IF NECESSARY. EVEN WITHOUT A HIGH WIND
WARNING...GRADIENT SOUTHERLY WINDS WILL FREQUENTLY GUST TO 50 MPH
ACROSS NORTHEAST AND EAST CENTRAL KS...SO HIGH END WIND ADVISORY
CRITERIA WILL CONTINUE.

SHORT RANGE MODELS CONTINUE TO INDICATE CONVECTIVE INITIATION LATE
THIS AFTERNOON ALONG OR IN THE VICINITY OF THE DRYLINE.  WILL
PROVIDE A CONVECTIVE ANALYSIS/DISCUSSION BY EARLY THIS AFTERNOON.

CAVANAUGH

&&

.PREV DISCUSSION... /ISSUED 617 AM CDT MON MAR 23 2009/

UPDATE...
UPDATED THE AVIATION DISCUSSION FOR THE 12Z TAFS.

DISCUSSION...
SEE PREV DISCUSSION.

AVIATION...
MAIN UNCERTAINTY WITH THE FORECAST IS TRYING TO TIME WHEN TS WILL
MOVE ACROSS THE TERMINALS. CONTINUED MOISTURE ADVECTION FROM THE
SOUTH SHOULD PROMOTE AN MVFR STCU DECK...WHICH 11Z SATELLITE SHOWS
DEVELOPING RAPIDLY OVER CENTRAL OK. HOWEVER FORECAST SOUNDINGS PROG
THE BOUNDARY LAYER REMAINING CAPPED THROUGH MUCH OF THE DAY. TRIED
TO INDICATE /WITH A TEMPO/ WHEN THE DRYLINE/COLD FRONT WOULD MOVE
ACROSS BRINGING THE BEST LIFT AND TS INTO THE TERMINALS. HEDGED THE
TAFS A LITTLE SLOWER THAN THE NAM DEPICTION SINCE THE GFS IS
SLIGHTLY SLOWER WITH THE FRONT. LATER FORECASTS WILL LIKELY NEED TO
REFINE THE TIMING.

WOLTERS

PREV DISCUSSION.../335 AM CDT MON MAR 23 2009/
TODAY/TONIGHT...MAIN FORECAST CONCERN WILL FOCUS ON CONVECTIVE
CHANCES THIS AFTERNOON INTO THE OVERNIGHT HOURS AND LIKEWISE
POTENTIAL OF SEVERE WEATHER.

EARLY THIS MORNING...WATER VAPOR ANALYSIS REVEALED A LEADING
WELL-DEFINED SHORTWAVE TROUGH ACROSS SOUTHERN COLORADO IN PART OF A
LARGER SCALE TROUGH CENTERED OVER THE CENTRAL ROCKIES. INITIAL
ASCENT WITH A BROAD DISTURBANCE LED TO SCATTERED SHOWERS ACROSS THE
CWA WITH MOST RECENTLY SOME MORE ENHANCED CONVECTION ON THE BACKSIDE
OF THIS ACTIVITY OVER EASTERN NEBRASKA INTO FAR NORTHEAST KANSAS. AT
THE SURFACE...BREEZY SFC WINDS HAVE ALLOWED TEMPERATURES TO REMAIN
QUITE WARM. DEWPOINTS CONTINUE TO REMAIN IN THE MIDDLE/UPPER 40S
OVER THE CWA WITH LOWER/MIDDLE 50S OVER CENTRAL KANSAS. RICHER BUT
STILL MODIFIED GULF AIR RESIDES ACROSS SOUTH CENTRAL TEXAS WHERE
DEWPOINTS REMAIN IN THE 60S.

MOST AREAS BEHIND THIS INITIAL ACTIVITY HAVE BECOME MOSTLY CLEAR
WITH LARGE SCALE SUBSIDENCE BUT MODEL GUIDANCE IS PERSISTENT IN
QUICKLY DEVELOPING WIDESPREAD LOW LEVEL STRATUS BY 14Z OVER MOST OF
CENTRAL/EASTERN KANSAS WHICH SEEMS REASONABLE. A SFC LOW OVER
NORTHEAST COLORADO WILL CONTINUE TO DEEPEN THIS MORNING TIGHTENING
THE PRESSURE GRADIENT AND SENDING THE CWA INTO WIND ADVISORY
CRITERIA BY MID MORNING. EXPECT WINDY SOUTHERLY CONDITIONS AHEAD OF
THE SYSTEM THROUGHOUT THE DAY WITH SPEEDS OF AT LEAST 30 MPH WITH
GUSTS TO 45 TO 50 MPH AT TIMES. THIS DEEP FETCH OF SOUTHERLY FLOW
WILL CONTINUE TO ADVECT MOISTURE INTO THE REGION...AND ANTICIPATE TO
REALIZE MIDDLE TO UPPER 50 DEWPOINTS IN MOST OF THE CWA BY LATE THIS
AFTERNOON.

THE AFOREMENTIONED SFC LOW WILL LIFT NORTHEASTWARD INTO CENTRAL
NEBRASKA AS WILL THE LEAD IMPULSE CURRENTLY OVER SOUTHERN COLORADO.
BY EARLY AFTERNOON...THE SFC LOW WILL BEGIN TO OCCLUDE AND
CONVECTION WILL RAPIDLY DEVELOP WITHIN THIS VICINITY NEAR THE SFC
LOW. TO THE SOUTH OF THE LOW...A COLD FRONT AND DRYLINE WILL TRAIL
SOUTH TO SOUTHWEST INTO CENTRAL KANSAS. THE DRYLINE WILL BE LOCATED
FROM NEAR CONCORDIA TO SALINA TO HUTCHINSON TO HARPER BY LATE
AFTERNOON. THE COLD FRONT WILL BEGIN TO ENCROACH ON THE NORTHERN
PORTION OF THIS SFC BOUNDARY...RESULTING IN A TRIPLE POINT SOUTH OF
SALINA. WITH LARGE SCALE ASCENT INCREASING...ADDITIONAL SFC FORCING
FROM THE OVERTAKING COLD FRONT...LOCALIZED DRYLINE
CIRCULATIONS...AND ANY SFC HEATING...EXPECT CONVECTIVE INITIATION TO
OCCUR BY LATE AFTERNOON INTO THE EARLY EVENING HOURS ALONG THESE
BOUNDARIES...WITH THE INITIAL ACTIVITY NEAR/NORTH OF THE TRIPLE
POINT...THEN DEVELOPING SOUTHWARD. THE DEGREE OF INSTABILITY REMAINS
IN QUESTION AS IT WILL BE STRONGLY TIED TO THE QUALITY OF ADVECTED
MOISTURE BY AFTERNOON IN ADDITION TO THE AMOUNT OF SFC HEATING. RH
VERTICAL SLICES SHOW LITTLE APPRECIABLE CLOUD COVER ABOVE
H8...THEREFORE IF GOOD MIXING CAN COMMENCE...ITS FEASIBLE MORE
BREAKS IN THE CLOUDS MAY OCCUR AND IMPROVED SFC HEATING WILL LEAD TO
INCREASED INSTABILITY. ATTM...EXPECT A NARROW CORRIDOR OF SBCAPE OF
1000 TO 1500 J/KG PRIOR TO CONVECTIVE INITIATION. VERTICAL WIND
PROFILES WILL CERTAINLY BE SUPPORTIVE OF ORGANIZED CONVECTION. 0-3
SRH AT CI WILL BE NEAR 300 M2/S2...INCREASING TO 450+ M2/S2 AFTER
DARK AS THE LLJ INCREASES. INITIAL STORM MODE IS EXPECTED TO BE
DISCRETE IN NATURE ACROSS NORTH CENTRAL KANSAS BUT MAY QUICKLY
TRANSITION TO A MORE LINEAR SYSTEM AS SHEAR VECTORS ARE MORE
PARALLEL TO DEVELOPING CONVECTION AND LIKEWISE MAY QUICKLY SEED
DOWNSTREAM CONVECTION. OVER CENTRAL AND SOUTH CENTRAL
KANSAS...CONVECTION MAY REMAIN MORE DISCRETE FOR A LONGER DURATION
AS SHEAR VECTORS REMAIN MORE PERPENDICULAR WITH RESPECT TO SFC
BOUNDARY AND THE COLD FRONT IS SLOWER IN OVERTAKING THE DRYLINE.
REGARDLESS...WITH SEVERAL INGREDIENTS IN PLACE TO SUPPORT ORGANIZED
LONG-LIVED CONVECTION...SEVERE WEATHER APPEARS A REAL POSSIBILITY
LATE THIS AFTERNOON INTO THE EVENING HOURS ACROSS THE TOPEKA CWA.
LARGE HAIL...DAMAGING WINDS...AND A FEW TORNADOES WILL BE POSSIBLE
DURING THIS PERIOD. THE GREATEST THREAT FOR TORNADOES WILL BE
ASSOCIATED WITH DISCRETE CONVECTION...WHICH ATTM APPEARS MORE
PLAUSIBLE ACROSS THE SOUTHWEST HALF OF THE CWA. HOWEVER AS THE LLJ
INCREASES...LOW LEVEL SHEAR PROFILES WILL BECOME VERY SUPPORTIVE
WITH 0-1 SRH INCREASING TO 300 M2/S2...WHICH WILL CONTINUE THE
THREAT OF TORNADOES WITHIN BROKEN LINE SEGMENTS AND/OR SUPERCELL
STORMS. A TRANSITION TO A SQUALL LINE IS EXPECTED A COUPLE HOURS
AFTER SUNSET AS INSTABILITY BEGINS TO WANE AND CONTINUED SEEDING OF
CONVECTION. THE POTENTIAL FOR STRAIGHT-LINE WIND DAMAGE WILL EXIST
WITH THIS LINE OF STORMS...ESPECIALLY WITH BOWING SEGMENTS THAT
MANAGE TO TRANSFER DOWNWARD MOMENTUM OF STRONG WINDS THAT EXIST JUST
ABOVE THE SFC. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH ALL
ROBUST CONVECTION...BUT ESPECIALLY AFTER DARK ACROSS THE SOUTHEAST
HALF OF THE CWA. THE LINE OF CONVECTION IS EXPECTED TO BE SOMEWHAT
PROGRESSIVE IN NATURE AND 3 HOUR FLASH FLOOD GUIDANCE IS RUNNING
NEAR 2 INCHES...BUT THERE MAY BE LOCALIZED AREAS OF TRAINING AND
THIS WILL NEED TO BE MONITORED AS THE CONVECTIVE SYSTEM GROWS AFTER
DARK.

MOST OF THE ACTIVITY SHOULD BE EAST OF THE AREA BY SUNRISE
TUESDAY...BUT HELD ON TO SLIGHT CHANCES IN FAR EAST FOR SOME
POTENTIAL LINGERING SHOWERS. OTHERWISE...MUCH MORE TRANQUIL WEATHER
EXPECTED TUESDAY INTO WEDNESDAY. NEXT CHANCE OF PRECIPITATION WILL
ARRIVE ON THURSDAY INTO FRIDAY...BUT MADE LITTLE CHANCES TO GOING
FORECAST FOR THIS TIME PERIOD AND BEYOND. AFTER WELL ABOVE NORMAL
TEMPERATURES TODAY...A RETURN TO MORE SEASONAL READINGS CAN BE
EXPECTED FOR THE REMAINDER OF THE WORK WEEK.

BLAIR

&&

.TOP WATCHES/WARNINGS/ADVISORIES...HIGH WIND WARNING UNTIL 7 PM MONDAY FOR KSZ008-KSZ009-KSZ010-
KSZ020-KSZ021-KSZ022-KSZ023-KSZ034-KSZ035-KSZ036-KSZ037.

WIND ADVISORY UNTIL 7 PM MONDAY FOR KSZ011-KSZ012-KSZ024-KSZ026-
KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
528 AM CDT MON MAR 23 2009

KSZ008>012-020>024-026-034>040-054>056-058-059-241030-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
528 AM CDT MON MAR 23 2009

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

.DAY ONE...TODAY AND TONIGHT

STRONG SOUTHERLY WINDS ARE EXPECTED TO INCREASE TO 30 TO 35 MPH
WITH GUSTS OF 40 TO 50 MPH BY MID MORNING THROUGH THE EARLY
EVENING HOURS. A WIND ADVISORY IS IN EFFECT THROUGH 7 PM CDT.

THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS PORTIONS OF NORTH
CENTRAL KANSAS BY MID TO LATE AFTERNOON AND MOVE EAST INTO
NORTHEAST AND EAST CENTRAL KANSAS DURING THE EVENING HOURS.
INSTABILITY AND FAVORABLE WIND SHEAR WILL SUPPORT THE POTENTIAL
FOR SEVERE WEATHER...WITH LARGE HAIL...DAMAGING WINDS AND A FEW
TORNADOES POSSIBLE. DURING THE EVENING...THIS ACTIVITY WILL
GRADUALLY EVOLVE INTO A LINE OF STORMS AND MOVE EAST ACROSS THE
REMAINDER OF NORTHEAST AND EAST CENTRAL KANSAS. IN
ADDITION...THERE IS THE POTENTIAL FOR STORMS TO DEVELOP OVER THE
SAME AREA DURING THE OVERNIGHT HOURS. THIS COULD LEAD TO THE
POTENTIAL OF FLASH FLOODING FROM LOCALLY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL LIKELY BE NEEDED LATE THIS AFTERNOON INTO TONIGHT.

BLAIR