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November 18, 2010

NE Baltimore windstorm ruled an EF-1 tornado

The National Weather Service concluded tonight that the violent windstorm that struck Northeast Baltimore and Parkville was an EF-1 tornado with top winds of 85 to 100 mph. Damage was tracked along a path five miles long, all done within the span of four minutes.

But the tornado was part of a more complex storm that included powerful straight-line winds, too. Those winds, in fact, caused most of the damage. The tornado was on the ground for less than a minute, the surveyors concluded. 

Here is the NWS report, published, as is their custom, in all capital letters:

"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."
Posted by Frank Roylance at 6:22 PM | | Comments (0)
Categories: Tornadoes
        

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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff
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