082   
NOUS41 KBOX 141911  
PNSBOX  
CTZ002>004-MAZ002>024-026-NHZ011-012-015-RIZ001>008-151911-  
  
PUBLIC INFORMATION STATEMENT  
NATIONAL WEATHER SERVICE TAUNTON MA  
311 PM EDT FRI JUL 14 2006  
  
COMPILATION OF TWO STORM SURVEYS FOR SEVERE THUNDERSTORMS JULY 11  
2006.  
  
...MARBLEHEAD MASSACHUSETTS MULTIPLE MICROBURST 357-430 PM  
TUESDAY JULY 11 2006...  
  
A NATIONAL WEATHER STORM SURVEY OF STORM DAMAGE HAS REACHED A  
PRELIMINARY CONCLUSION THAT MULTIPLE WET MICROBURSTS AFFECTED  
MARBLEHEAD NECK AND THE ADJACENT WATERS BETWEEN APPROXIMATELY  
357 PM AND 430 PM ON TUESDAY JULY 11TH.  
  
THIS SURVEY INCLUDED VISUAL ASSESSMENT...INTERVIEWS WITH MANY ALONG  
THE PRIMARY DAMAGE PATH...RECEIPT OF WIND INSTRUMENT WINDS SPEEDS...  
NEWSPAPER ACCOUNTS AND CORRELATION WITH NATIONAL CLIMATIC DATA  
CENTER /NCDC/ ARCHIVED TAUNTON RADAR REFLECTIVITY...VELOCITY AND  
SPECTRUM WIDTH DATA.  
  
WESTERLY WINDS OF ABOUT 90 MILES AN HOUR OCCURRED IN THE CORE DAMAGE  
ZONE CENTERED FROM MARBLEHEAD HARBOR SOUTHWEST OF THE CORINTHIAN  
YACHT CLUB /CYC/ CUTTING ACROSS CORINTHIAN LANE THEN ACROSS THE  
SOUTHERN PORTION OF BARKER LANE AND OUT TO SEA. THE LAND DAMAGE PATH  
WAS SHORT...PRIMARILY BECAUSE THE LAND IS ONLY ABOUT 700 FEET WIDE  
FROM THE POINT OF IMPACT AND EXIT ACROSS MARBLEHEAD NECK.  
  
THERE WERE NO KNOWN INJURIES.  
  
THE MAIN DAMAGE PATH WAS APPROXIMATELY 150 FEET WIDE. IT CONSISTED OF  
PRIMARILY TREE DAMAGE AND COMPARATIVELY MINOR STRUCTURAL DAMAGE ALONG  
WITH SUBSTANTIAL DAMAGE TO SAILING VESSELS AND AT LEAST ONE AUTO.  
  
SPORADIC TREE DAMAGE OCCURRED ABOUT 600 FEET NORTH OF THE STREET  
SURVEYED CORE DAMAGE PATH...NEAR MANLEY STREET...AS WELL VARIABLE  
DISTANCES TO THE SOUTH AND SOUTHWEST OF THE CORE PATH...BEGINNING ON  
FOSTER STREET NEAR THE HARBOR AVENUE INTERSECTION THEN UP TO THE  
EASTERN YACHT CLUB FINALLY TO OCEAN AVENUE NEAR ITS INTERSECTION WITH  
HARBOR AVENUE.  
  
THERE WAS A TIGHT GRADIENT TO THE PRIMARY DAMAGE CORE.  
  
TAUNTON RADAR IMPLIED STRONG ROTATION VIA VELOCITY DATA...AND ALSO  
STRONG SHEAR IN SPECTRUM WIDTH DATA...INDICATING TURBULENT FLOW ALOFT  
IN THE INTERFACE BETWEEN A PORTION OF THE UPDRAFT AND THE WET  
MICROBURST DOWNDRAFT FROM A CONSTANTLY ENLARGING STORM SYSTEM.  
  
MULTIPLE EYEWITNESS ACCOUNTS SPOKE OF A WIND DRIVEN DAMAGE FROM WEST  
TO EAST.  
  
THERE WAS ONE REPORT OF A WATERSPOUT FROM A PATRON AT RESTAURANT  
ACROSS THE HARBOR BUT WE WERE NOT ABLE TO INTERVIEW THAT PERSON.  
  
THIS 4 PM STORM REPORTEDLY DID HAVE HAIL PRECEDING IT...ESTIMATED 1.5  
INCH DIAMETER AT APPROXIMATELY 355 PM...BUT THIS WAS CLEARLY A  
SEPARATE STORM FROM THE 305-320 PM THREE INCH DIAMETER HAILSTONE  
STORM...THE SECOND LARGEST DIAMETER HAILSTONES KNOWN TO HAVE OCCURRED  
IN MASSACHUSETTS.  
  
IT IS POSSIBLE...AFTER MORE DATA ARRIVES...INCLUDING EVALUATION OF  
STORM RELATIVE MOTION DATA...BAROGRAPHS...ADDITIONAL WIND DAMAGE DATA  
AND FURTHER VISUAL ACCOUNTINGS...THAT AN UPDATED POST EVENT  
EVALUATION WOULD REVEAL A RAIN WRAPPED TORNADO WAS EMBEDDED IN THE  
INITIAL VIOLENT WESTERLY WIND.  HOWEVER THE PREPONDERANCE OF  
INFORMATION GLEANED THROUGH 3 PM FRIDAY JULY 14TH...SUGGESTS THAT WAS  
A STRAIGHT LINE WIND EVENT.  
  
THE FOLLOWING IS TIME APPROXIMATE AND MAY NEED TO BE ADJUSTED IN THE  
FINAL REPORT FOUND IN THE NATIONAL CLIMATIC DATA CENTER DOCUMENT  
TITLED...STORM DATA. STORM DATA WILL ALSO REFLECT LATER UPDATED TIME  
INFORMATION ON THE EVENTS ALREADY LISTED.  
  
AT ABOUT 340 PM TO 345 PM...APPARENT NORTHEAST WIND STORM OUTFLOW  
FROM STORMS TRAVELING WEST TO EAST...JUST NORTH OF MARBLEHEAD...  
ARRIVED AT THE MOUTH OF MARBLEHEAD HARBOR CAUSING SEA SPRAY.  FOR  
THOSE REVIEWING VELOCITY DATA IN THE 0.4 DEGREE SLICE...THE  
CENTERPOINT OF THE TAUNTON RADAR BEAM AT THIS DISTANCE INTERSECTS THE  
ATMOSPHERE/STORMS AT ABOUT 2000 FEET. THE NORTHEAST SURFACE OUTFLOW  
PROBABLY WAS MUCH SHALLOWER AND UNDERCUT THE WIND FIELDS SEEN AT 2000  
FEET.  
  
SOMETIME BETWEEN 357 PM - 4 PM... A WHITE TEMPEST WAS REPORTED TO  
HAVE DEVELOPED OVER MARBLEHEAD HARBOR ON THE NECK SIDE OF THE  
HARBOR...ESTIMATED BY THE CYC RACE CHAIR TO BEGIN ABOUT 300 YARDS  
UPSTREAM FROM THE DOCK...AND ADVANCED TOWARD THE CORINTHIAN YACHT  
CLUB /CYC/ LIFTING 30 FOOT SAILING VESSELS APPROXIMATELY 20 FEET IN  
THE AIR AND CATAPULTING THEM END OVER END TOWARD THE DOCK. AN  
ANEMOMETER ON THE CYC DOCK WAS VIEWED TO REACH 95 MPH BEFORE IT BLEW  
OFF ITS MAST. A SAILING REGATTA HAD JUST FINISHED AND THERE WERE  
REPORTS OF PEOPLE BEING PINNED TO THE YACHT CLUB PORCH WALL BY THE  
WIND AS SAFETY WAS SOUGHT BY MANY. AT THE CLUB ITSELF AN ANEMOMETER  
TOPPED OUT AT 60 MPH.  
  
ONE ANEMOMETER ON CORINTHIAN LANE AT 401 PM RECORDED 74 MPH...TIME  
APPROXIMATE...WHILE A FAMILY MEMBER WAS WATCHING BRANCHES PEEL OFF A  
TREE AT ABOUT 414 PM...AGAIN TIME ESTIMATED.  
  
POLICE LOGS INDICATE THE FIRST CALL FOR TREES DOWN WAS AT 416 PM.  
  
WIND AND OR DEBRIS BLEW OUT SOME WINDOWS ON HOMES ALONG CORINTHIAN  
LANE AND MUCH OF THE SHORN TREE DAMAGE WITH BRANCHES ESTIMATED 9  
INCHES TO A FOOT IN DIAMETER...WERE TORN OFF THE MID AND UPPER  
PORTIONS OF TREES EITHER SIDE OF CORINTHIAN LANE AND THEN ACROSS  
HARBOR AVENUE ONTO PROPERTIES SOUTH OF BARKER LANE.  
  
THERE WERE MANY REPORTS OF EXCESSIVELY HEAVY RAIN ACCOMPANYING OR  
JUST FOLLOWING THIS BURST OF DAMAGING WIND...VISIBILITY DOWN TO 5  
FEET...WINDOWS FOGGING AND AT LEAST ONE REPORT EARS POPPING... THE  
LATTER POSSIBLY RELATED TO A RAPID CHANGE IN AIR PRESSURE NEAR THE  
TIME OF THIS EVENT.  
  
ENHANCED FUJITA SCALE ESTIMATES FOR BOTH HARD AND SOFTWOOD COMBINED  
WITH ANEMOMETER READINGS THAT WERE NOT CHECKED FOR CALIBRATION BOTH  
IN TIME AND WIND SPEED...STRONGLY IMPLY WIND SPEEDS OF NEAR 90 MILES  
AN HOUR.  
  
THAT WAS THE FIRST MICROBURST...  
  
WINDS CONTINUED TO BLOW STRONG AFTER THE INITIAL DAMAGE BURST..THEN  
THERE WAS AT LEAST ONE REPORT OF A SUDDEN SHIFT TO A SOUTHERLY WIND  
COMPONENT PROBABLY SOMETIME BETWEEN 420 PM AND 425 PM CAUSING FURTHER  
DAMAGE ON CORINTHIAN LANE AND POSSIBLY CONFUSING DEBRIS PATTERN  
ASSESSMENT. THE REPORT BELOW ALSO SUPPORTS THIS SECONDARY  
MICROBURST EVENT.  
  
REPORTS FROM WEATHERFLOW WIND INSTRUMENTS ON CHILDREN'S ISLAND ABOUT  
1 MILE TO THE NORTHEAST OF MARBLEHEAD NECK AND KINDLY SHARED WITH THE  
NATIONAL WEATHER SERVICE WERE AS FOLLOW...  
  
425PM  285 DEGS  11 GUST 26 MPH  
430PM  230 DEGS  48 GUST 73 MPH  
435PM  195 DEGS  18 GUST 47 MPH  
440PM   92 DEGS  16 GUST 24 MPH.  
  
WE WILL CONTINUE TO ACCEPT BARAOGRAPH TRACES...DETAILED ANEMOMETER  
INFORMATION AND EYEWITNESS ACCOUNTS BOTH VERBAL AND VIDEO.  
  
WE EXTEND APPRECIATION TO THE NUMEROUS OFFICIALS /POLICE-FIRE/  
SKYWARN SUPPORT...EYEWITNESS ACCOUNTS-REPORTS FROM THE CORINTHIAN...  
EASTERN AND PLEON YACHT CLUBS AS WELL AS THOSE ALONG CORINTHIAN AND  
BARKER LANES WHO WILLINGLY SHARED A RECOUNTING OF EVENTS TOWARD A  
BETTER UNDERSTANDING OF THE PROCESSES INVOLVED.  
  
NOW TO THE TORNADO IN WENDELL MASSACHUSETTS BELOW...  
  
...MICROBURST AND F2 TORNADO CONFIRMED IN WENDELL MASSACHUSETTS ON  
TUESDAY JULY 11...  
  
A DAMAGE SURVEY WAS CONDUCTED IN WENDELL MASSACHUSETTS TODAY BY THE  
NATIONAL WEATHER SERVICE IN TAUNTON...IN COOPERATION WITH THE SKYWARN  
AMATEUR RADIO COORDINATOR FOR WESTERN MASSACHUSETTS...THE  
MASSACHUSETTS EMERGENCY MANAGEMENT AGENCY...THE MASSACHUSETTS  
DEPARTMENT OF CONSERVATION AND RECREATION...AND THE ATHOL FIRE  
DEPARTMENT.  
  
BASED UPON THE DAMAGE SURVEY...INTERVIEWS WITH EYEWITNESSES AND  
DOPPLER RADAR DATA...THE SEVERE THUNDERSTORM PRODUCED A COMBINATION  
OF STRAIGHT LINE WIND DAMAGE AND A TORNADO...WHICH HAS BEEN RATED AS  
A STRONG F2 WITH WIND SPEEDS NEAR 155 MPH.  
  
DAMAGE BEGAN AROUND 230 PM EDT...ABOUT 200 YARDS WEST OF MONTAGUE  
ROAD. STRAIGHT LINE WIND DAMAGE EXTENDED FROM MONTAGUE ROAD 1.5  
MILES EAST TO WICKET POND IN THE WENDELL STATE FOREST. LARGE  
OAK...MAPLE AND PINE TREES WERE UPROOTED AND SNAPPED IN THIS AREA.  
SOME OAKS JUST OVER TWO FEET IN DIAMETER WERE SNAPPED ABOUT 10 TO  
15 FEET FROM THE GROUND. DAMAGE FROM THE MICROBURST EXTENDED ALONG A  
PATH OF ONE AND A HALF MILES IN LENGTH...AND ANYWHERE FROM 50 TO  
300 YARDS WIDE. WIND SPEEDS WERE ESTIMATED AS HIGH AS 90 MPH.  
  
TORNADO DAMAGE FIRST APPEARED ON THE NORTHEAST CORNER OF WICKET  
POND. AN EYEWITNESS REPORTED SEEING A 6 FOOT WAVE FORM ON THE POND.  
IN ADDITION...THE PARK SUPERVISOR REPORTED THAT THE LEVEL OF THE POND  
WAS LOWERED 6 TO 8 INCHES BY THE STORM. ON THE WEST SIDE OF WICKET  
POND MANY TREES SNAPPED 15 TO 20 FEET ABOVE THE GROUND...WITH DEBRIS  
IN A CHAOTIC PATTERN.  
  
THE NEXT AREA OF DAMAGE WAS ON WICKET POND ROAD WHERE THE MOST SEVERE  
DAMAGE OCCURRED. TREES AS LARGE AS 3 FEET IN DIAMETER WERE UPROOTED.  
BARK WAS STRIPPED OFF TREES AND A HOUSE HAD PART OF ITS ROOF TORN  
OFF. THE TORNADO TRACKED TO THE EAST ALONG WICKET POND ROAD...  
PASSING OVER DEPOT ROAD WHICH IS IN WENDELL CENTER. PART OF A ROOF  
WAS TORN OFF AN OLD BARN AND MANY TREES WERE UPROOTED.  
  
AFTER CROSSING DEPOT ROAD...THE TORNADO CONTINUED TO TRACK TO THE  
EAST...PASSING NORTH OF MORSE VILLAGE ROAD. A CONSTRUCTION STORAGE  
TRAILER WAS COMPLETELY DESTROYED AND ITS ROOF WAS WRAPPED AROUND  
A TREE. TREES WERE ALSO UPROOTED OR SNAPPED IN THIS AREA. DAMAGE  
CAME TO AN END ABOUT ONE HALF MILE EAST OF NEW SALEM ROAD NEAR A  
POWER LINE.  
  
THE PATH LENGTH OF THE TORNADO WAS APPROXIMATELY 2.9 MILES LONG.  
ITS AVERAGE WIDTH WAS 200 YARDS...VARYING FROM 100 TO 300 YARDS.  
  

 
DRAG FOR MARBLEHEAD  
AL DUNHAM FOR WENDELL