Sunday, June 21, 2009

Washington DC Precipitation Update: Rainfall Surplus Expands
Weather Service Confirms Baltimore Co. Tornado

Images (click to enlarge): Washington DC 2009 vs. 2008 monthly precipitation, CapitalClimate chart from National Weather Service (NWS) data; Maryland/Delaware/Northern Virginia month to date and year to date precipitation departure from average from NWS

Midnight Update: Added 2009 vs. 2008 monthly precipitation chart

Original post:
After another round of showers and thunderstorms in the Washington/Baltimore region (including an EF-1 tornado in Baltimore County) on Saturday, the Washington DC June rainfall total now stands at over 250% of the long-term average. For the year to date, the surplus is 25%. The daily/monthly/yearly totals for the Washington/Baltimore region through June 20:
Washington National 0.39"/5.46"/22.73"
Washington Dulles 0.46"/6.61"/26.39"
Baltimore (BWI) 0.32"/5.41"/24.69"
Baltimore Sun article on the tornado:
Tornado knocks down trees, power lines in Baltimore Co.
WBAL radio:
Tornado Tore Through Essex

National Weather Service report:
...TWO TORNADOES AND A WATERESPOUT CONFIRMED FROM SATURDAY...

SATURDAY AFTERNOON THREE WEAKER THUNDERSTORMS DEVELOPED QUICKLY
INTO SUPERCELLS WHILE MOVING ACROSS HARFORD...BALTIMORE...AND ANNE
ARUNDEL COUNTY. MUCH OF THE REASON FOR THIS WAS DUE TO THE STORMS
IMPACTING THE BAY BREEZE OVER THESE COUNTIES. THE BAY BREEZE IS
WHERE SLIGHTLY COOLER AIR OFF THE BAY MOVES OVER THE ADJACENT
SHORELINE COMMUNITIES AND SHIFTS THE SURFACE WIND DIRECTION ENOUGH
TO ASSIST WITH TORNADO FORMATION.

THE HARFORD COUNTY STORM PRODUCED A WEAK EF-0 TORNADO...THE
BALTIMORE COUNTY STORM PRODUCED EF-1 DAMAGE AT ITS WORST
POINT...AND THE ANNE ARUNDEL STORM DEVELOPED A WATERSPOUT JUST AS
IT MOVED OVER THE BAY.

BALTIMORE COUNTY...

AT 3:44 PM A TORNADO TOUCHED DOWN IN ESSEX MARYLAND. IT KNOCKED
DOWN A TREE THAT SEVERELY DAMAGED A HOME. SEVERAL OTHER TREES AND
BRANCHES WERE KNOCKED DOWN AS WELL. STREETS AFFECTED INCLUDED
WOODLYNN RD... LANCE AVE... KINWAT AVE... TIBSEN AVE... AND
HOMBURG AVE. MINOR SHINGLE AND SIDING DAMAGE WAS REPORTED THROUGH
THE COMMUNITY. DAMAGE IN THIS AREA WAS CATEGORIZED AS EF-0 DAMAGE
WITH PEAK WINDS AROUND 70 MPH.

THE STORM CONTINUED SOUTHEAST...MAINLY AS A FUNNEL CLOUD THAT DID
NOT REACH TO THE GROUND... BUT IT DID CAUSE A FEW LARGE BRANCHES
TO GET KNOCKED DOWN SPORADICALLY ALONG THE BACK RIVER NECK RD
CORRIDOR.

THE TORNADO INTENSIFIED AS IT APPROACHED BROWNS CREEK AND
BALLISTON POINT. AT 3:49 THE TORNADO WAS VIDEOTAPED NEARING
BROWNS CREEK. THE STORM MOVED ACROSS THE CREEK AND OVER BALLISTON
POINT AT 3:50 PM. THE TORNADO UPROOTED OR SNAPPED DOWN A
SIGNIFICANT PORTION OF THE LARGE TREES IN THE COMMUNITY ALONG
ISLAND VIEW ROAD...DOZENS IN ALL. THE STORM DISSIPATED AS IT MOVED
OVER THE BAY AT 3:52 PM.

RESIDENTS OF ISLAND VIEW ROAD HAD VIDEO AND PICTURES OF THE
TORNADO AND INDICATED SEEING THE TORNADO WARNING ON TELEVISION
BEFORE THE STORM STRUCK. AN NWS DAMAGE SURVEY REVEALED EF-1 DAMAGE
IN THE BALLISTON POINT AREA WITH PEAK WINDS ESTIMATED TO BE 90
MPH. TOTAL PATH LENGTH FOR THIS TORNADO WAS 5 MILES...ALTHOUGH THE
CIRCULATION SKIPPED AS IT MOVED SOUTHEAST. PATH WIDTH WAS 150
YARDS AT ITS WIDEST.

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