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Baltimore City/County Macroburst with
Embedded Tornado Damage
November 17, 2010

000
NOUS41 KLWX 182301
PNSLWX
DCZ001-MDZ003>007-009>011-013-014-016>018-501-502-VAZ025>031-
036>040-042-050>057-501>504-WVZ050>053-055-501>506-191115-
DISTRICT OF COLUMBIA-WASHINGTON-FREDERICK MD-CARROLL-
NORTHERN BALTIMORE-HARFORD-MONTGOMERY-HOWARD-SOUTHERN BALTIMORE-
PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-CALVERT-
EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA-
ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON-
ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER-
PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-
KING GEORGE-NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND-
EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY-
WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL-
WESTERN PENDLETON-EASTERN PENDLETON-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
601 PM EST THU NOV 18 2010

...NATIONAL WEATHER SERVICE CONFIRMS EF-1 TORNADO IN BALTIMORE CITY 
AND BALTIMORE COUNTY ON WEDNESDAY MORNING NOVEMBER 17 2010...

LOCATION...HAMILTON IN BALTIMORE CITY AND PARKVILLE IN BALTIMORE 
COUNTY MARYLAND
DATE...NOVEMBER 17 2010
ESTIMATED TIME...1:35 AM EST
MAXIMUM EF-SCALE RATING...EF1
ESTIMATED MAXIMUM WIND SPEED...100 MPH
MAXIMUM PATH WIDTH...250 YARDS
PATH LENGTH...0.4 MILES
BEGINNING LAT/LON...39.3665N / 76.5705W 
ENDING LAT/LON...39.3772N / 76.5601W 
* FATALITIES...NONE
* INJURIES...3 MINOR
* THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT 
TO CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND 
PUBLICATION IN NWS STORM DATA.

...SUMMARY...

AFTER AN EXTENSIVE REVIEW OF NATIONAL WEATHER SERVICE AND FEDERAL 
AVIATION ADMINISTRATION WEATHER RADARS...GROUND OBSERVATIONS... AN 
AERIAL SURVEY...AND EYEWITNESS ACCOUNTS...THE BALTIMORE/WASHINGTON 
WEATHER FORECAST OFFICE OF THE NATIONAL WEATHER SERVICE HAS 
DETERMINED THAT A TORNADO ESTIMATED AT A CATEGORY 1 ON THE ENHANCED 
FUJITA SCALE STRUCK NORTHEAST BALTIMORE DURING THE EARLY MORNING 
HOURS OF WEDNESDAY NOVEMBER 17TH...WITH ESTIMATED WIND SPEEDS FROM 85 
TO 100 MPH.

THE TORNADO WAS FORMED WITHIN A LINE OF THUNDERSTORMS WHICH SPANNED 
FROM PENNSYLVANIA TO NORTH CAROLINA ON WEDNESDAY MORNING NOVEMBER 
17TH.  THIS LINE OF THUNDERSTORMS WAS RACING TOWARDS THE NORTHEAST 
AT 70 MPH AS IT CROSSED THE BALTIMORE/WASHINGTON REGION.  IT IS 
HYPOTHESIZED THAT A STRONG DOWNBURST OF WIND...ALSO KNOWN AS A 
REAR-INFLOW JET...DESCENDED FROM APPROXIMATELY ONE MILE HIGH IN THE 
ATMOSPHERE DOWN TO THE GROUND...AND BECAME COINCIDENT WITH THE LINE 
OF THUNDERSTORMS AS IT MOVED ACROSS THE CITY OF BALTIMORE. 

THIS STRONG DOWNBURST OF WIND CAUSED A BREAK IN THE LONG LINE 
OF THUNDERSTORMS AND CREATED TWO SEPARATE THUNDERSTORM LINE 
SEGMENTS.  THE STRONG DOWNBURST OF WIND CONTINUED TO MODIFY 
THE THUNDERSTORMS...CREATING A SWIRLING WIND AT THE SOUTH END 
OF THE NEWLY FORMED NORTHERN SEGMENT.  THE SWIRLING WIND IN 
THIS TYPE OF THUNDERSTORM SYSTEM IS OFTEN REFERRED TO AS A 
BOOKEND VORTEX...AND IT RESULTED IN THE GENERATION OF A BRIEF 
EF-1 TORNADO.

THE PATH OF WIND DAMAGE FROM THE THUNDERSTORMS THAT ALSO 
PRODUCED THE BRIEF TORNADO STARTED ON THE WESTERN EDGE OF 
MORGAN STATE UNIVERSITY IN NORTHEAST BALTIMORE CITY AND THEN 
CONTINUED FOR APPROXIMATELY 5 MILES TO THE NORTHEAST TO 
GUNPOWDER STATE PARK IN BALTIMORE COUNTY.  IT SHOULD BE NOTED THAT 
THE VAST MAJORITY OF WIND DAMAGE ALONG THE 5 MILE LONG PATH WAS DUE 
TO STRAIGHT LINE WINDS FROM THE DESCENDING REAR-INFLOW JET AS IT HIT 
THE GROUND...REFERRED TO AS A MACROBURST. EMBEDDED WITHIN THE DAMAGE 
PATH OF THIS MACROBURST WERE TWO AREAS OF DAMAGE THAT ARE ASSOCIATED 
WITH THE EF-1 TORNADO.

THE DAMAGE FROM THE EF-1 TORNADO WAS IN TWO SEPARATE AREAS A HALF 
MILE APART.  THE FIRST AREA WAS ONE-TENTH OF A MILE LONG AND 175 
YARDS WIDE THAT INCLUDED THE DUTCH VILLAGE APARTMENT COMPLEX. THREE 
OF THE UNITS HAD THEIR ROOFS BLOWN OFF. THE ROOFS WERE NOT CLIPPED 
TO THE STRUCTURES. THERE WAS EXTENSIVE TREE DAMAGE. SEVERAL CARS 
WERE SHIFTED BY THE FORCE OF THE WIND. THE TORNADO LIFTED BRIEFLY. 
THEN THE SECOND AREA... APPROXIMATELY A HALF MILE NORTH OF THE FIRST 
AREA...WAS ONE-THIRD OF A MILE LONG AND 250 YARDS WIDE...CENTERED ON 
THE PERRING PARKWAY SHOPPING CENTER IN PARKVILLE.  EVIDENCE OF THE 
TORNADO INCLUDED RETAIL PROPERTY SURVEILLANCE CAMERAS WHICH SHOWED 
DEBRIS BLOWING IN DIFFERENT DIRECTIONS...TREES AND LIGHT POLES 
FALLING IN A CONVERGENT PATTERN...EYEWITNESS REPORTS...AND LEAF 
SPATTER ON ALL FOUR SIDES OF AUTOMOBILES AND STRUCTURES.

WITH THE SPEED OF THE STORMS MEASURED AT 70 MPH...ALONG WITH A 
DAMAGE PATH OF 5 MILES FROM THE THUNDERSTORM...IT IS 
DETERMINED THAT IT TOOK ONLY 4 MINUTES FOR THE MACROBURST TO 
ACCOMPLISH ITS 5 MILE PATH OF DAMAGE.  WITHIN THIS 4 MINUTE 
TIMEFRAME...THE EF-1 TORNADO WAS ON THE GROUND FOR LESS THAN 1 
MINUTE.

THE STORM PREDICTION CENTER IN NORMAN OKLAHOMA...IN CONJUNCTION 
WITH THE BALTIMORE/WASHINGTON WEATHER FORECAST OFFICE...ISSUED 
A SEVERE THUNDERSTORM WATCH FOR THE REGION AT 12:06 AM EST 
WEDNESDAY.  A SEVERE THUNDERSTORM WATCH IS ISSUED WHEN 
CONDITIONS ARE FAVORABLE FOR DAMAGING THUNDERSTORMS.  THIS 
ADVANCE NOTIFICATION WAS APPROXIMATELY 90 MINUTES PRIOR TO 
WHEN DAMAGE OCCURRED IN BALTIMORE CITY AND BALTIMORE COUNTY.  

THE BALTIMORE/WASHINGTON WEATHER FORECAST OFFICE ISSUED A 
SEVERE THUNDERSTORM WARNING FOR BALTIMORE CITY AND COUNTY AT 
1:04 AM EST WEDNESDAY MORNING.  A SEVERE THUNDERSTORM WARNING 
IS ISSUED WHEN WINDS OF GREATER THAN 58 MPH ARE EXPECTED.  
THIS WARNING PROVIDED APPROXIMATELY 32 MINUTES OF LEAD TIME 
PRIOR TO WHEN THE DAMAGE OCCURRED IN BALTIMORE CITY AND 
BALTIMORE COUNTY.

RECEIVING LIFE SAVING WARNINGS AT NIGHT CAN BE ACHIEVED WITH A 
NOAA WEATHER RADIO...WHICH CAN BE SET TO ALARM ONLY FOR LIFE 
THREATENING WATCHES AND WARNINGS FOR YOUR PARTICULAR COUNTY. 
FOR MORE INFORMATION...VISIT WWW.WEATHER.GOV/NWR 

THE NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON WEATHER FORECAST 
OFFICE WOULD LIKE TO THANK THE BALTIMORE COUNTY OFFICE OF HOMELAND 
SECURITY AND EMERGENCY MANAGEMENT...THE BALTIMORE CITY MAYORS OFFICE 
OF EMERGENCY MANAGEMENT...THE BALTIMORE COUNTY POLICE DEPARTMENT... 
THE BALTIMORE CITY POLICE DEPARTMENT...AND THE MARYLAND EMERGENCY 
MANAGEMENT AGENCY FOR THEIR ASSISTANCE IN THE SURVEY.

$$

LEE/STRONG



$$

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Page last modified: Nov 18, 2010 6:04 PM EST
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