Tuesday, May 26, 2009

Record Mid Atlantic Rainfall for May 26

Images (click to enlarge): 24-hour precipitation ending at 8 am, May 26, from National Weather Service/NOAA; Washington, DC 2008-9 monthly precipitation vs. average, CapitalClimate chart from NWS data

May 27 Update: Even with 4 more days providing several more opportunities for adding to the month's total, it's going to be hard for this May to reach the 10.66" recorded just last year at Washington National, which made it the 3rd wettest in Washington history. Nevertheless, May 2009 is already the 10th wettest May, and it's well within striking distance of the 8th or even 7th spot. Here are the current top 9:
1889 10.69
1953 10.69"
2008 10.66"
1886 10.60"
1948 8.87"
1989 7.77"
2003 7.06"
1946 6.99"
1897 6.97

Evening Update: More National Weather Service reports:
A RECORD RAINFALL OF 3.59 INCH(ES) WAS SET AT WASHINGTON DULLES DC TODAY.   
THIS BREAKS THE OLD RECORD OF 1.59 SET IN 2002.

**********************12 HOUR RAINFALL**********************

LOCATION 12 HOUR TIME/DATE COMMENTS
RAINFALL OF
(INCHES) MEASUREMENT

DISTRICT OF COLUMBIA

..DISTRICT OF COLUMBIA

WASHINGTON 3.63 1214 PM 5/26 LOCAL MESONET

MARYLAND

..PRINCE GEORGE'S COUNTY

GREENBELT 2.50 809 AM 5/26

VIRGINIA

..FAIRFAX COUNTY

HERNDON 3.03 929 AM 5/26 LOCAL MESONET
CHANTILLY 2.97 914 AM 5/26 LOCAL MESONET

..LOUDOUN COUNTY

STERLING 3.03 1129 AM 5/26 LOCAL MESONET
ASHBURN 2.50 1128 AM 5/26 LOCAL MESONET

**********************24 HOUR RAINFALL**********************

LOCATION 24 HOUR TIME/DATE COMMENTS
RAINFALL OF
(INCHES) MEASUREMENT

DISTRICT OF COLUMBIA

..DISTRICT OF COLUMBIA

NATIONAL ARBORETUM 2.55 824 AM 5/26 COOP
DALECARLIA RESERVIOR 2.02 800 AM 5/26 COOP
WASHINGTON 5.0 N 1.30 700 AM 5/26 COCORAHS

MARYLAND

..ANNE ARUNDEL COUNTY

LAUREL 2.7 E 4.01 800 AM 5/26 COCORAHS
SEVERN 2.0 W 3.35 700 AM 5/26 COCORAHS
BALTO/WASH INTL 2.58 800 AM 5/26 METAR
ODENTON 0.8 WSW 2.07 700 AM 5/26 COCORAHS

..CHARLES COUNTY

WALDORF 3.2 SW 2.69 700 AM 5/26 COCORAHS

..CITY OF BALTIMORE

BALTIMORE - CYLBUR 1.45 800 AM 5/26 COOP

..HOWARD COUNTY

CLARKSVILLE 3.40 800 AM 5/26 COCORAHS 1.0SE
LAUREL 2.90 1200 PM 5/26
COLUMBIA 1.7 W 2.83 600 AM 5/26 COCORAHS
NORTH LAUREL 1.5 ESE 2.65 700 AM 5/26 COCORAHS

..MONTGOMERY COUNTY

SILVER SPRING 0.9 N 4.10 700 AM 5/26 COCORAHS
TAKOMA PARK 0.6 NNW 3.71 700 AM 5/26 COCORAHS
WHITE OAK 1.2 N 3.40 700 AM 5/26 COCORAHS
WHEATON-GLENMONT 0.7 2.71 700 AM 5/26 COCORAHS
OLNEY 0.4 ESE 2.34 700 AM 5/26 COCORAHS

..PRINCE GEORGE'S COUNTY

GREENBELT 4.00 809 AM 5/26
LAUREL 3.49 800 AM 5/26 COCORAHS 2.0S

VIRGINIA

..ALBEMARLE COUNTY

RUCKERSVILLE 1.30 812 AM 5/26

..ARLINGTON COUNTY

ARLINGTON 1.1 NW 1.75 715 AM 5/26 COCORAHS
REAGAN NATIONAL 1.47 800 AM 5/26 METAR

..CITY OF ALEXANDRIA

ALEXANDRIA 1.8 S 1.99 740 AM 5/26 COCORAHS 1.8S

..CLARKE COUNTY

MOUNT WEATHER 2.76 700 AM 5/26 COOP

..FAIRFAX COUNTY

WASH DC/DULLES 3.63 800 AM 5/26 METAR
FRANCONIA 1.3 SSE 1.45 730 AM 5/26 COCORAHS

..FREDERICK COUNTY

STEPHENS CITY 2.2 E 1.61 700 AM 5/26 COCORAHS

..GREENE COUNTY

STANARDSVILLE 2.1 1.59 600 AM 5/26 COCORAHS

..LOUDOUN COUNTY

STERLING PARK 4.00 839 AM 5/26
STERLING NWS/WFO 2.87 700 AM 5/26 WFO STERLING
STERLING 2.15 700 AM 5/26 COCORAHS 3.7NNW
ROUND HILL 2.7 WSW 1.62 700 AM 5/26 COCORAHS

..PAGE COUNTY

LURAY 1.60 900 AM 5/26 COOP

..PRINCE WILLIAM COUNTY

LAKE RIDGE 1.7 SW 2.22 700 AM 5/26 COCORAHS 1.7SW

..ROCKINGHAM COUNTY

DALE ENTERPRISE 1.56 700 AM 5/26 COOP

PM Update: Daily totals through 5 pm as reported by NWS show National at 1.65". The totals for Dulles and BWI are as previously shown, and all 3 are daily records. Month-to-date/year-to-date totals are:
Washington National 6.95"/16.17"
Washington Dulles 8.35"/17.86"
Baltimore (BWI) 7.09"/17.95"
These are all at least 100% above average, but still below the monthly records for May. Notice the high percentage of the 5-month total accounted for by May alone.

Original post:
Heavy downpours overnight and into this morning have caused some local flash flooding in the Washington, DC region. Through mid afternoon, daily total rainfall amounts have already exceeded the record for May 26 at all 3 major reporting locations:
Washington National 1.66"
Washington Dulles 3.59"
Baltimore (BWI) 2.28"
The reading at Dulles is more than double the previous record for May 26, 1.59" in 2002. It's also close to the all-time daily record for May, 3.73" on May 11, 2008. The BWI amount is also a daily record, exceeding the 1.72" on May 26, 2001. At Washington National, the total is just slightly higher than the previous record of 1.49" in 2001.

The following rainfall amounts were reported by the National Weather Service as of 8 am this morning:
***********************6 HOUR RAINFALL***********************

LOCATION 6 HOUR TIME/DATE COMMENTS
RAINFALL OF
(INCHES) MEASUREMENT


VIRGINIA

...LOUDOUN COUNTY...
DULLES AIRPORT DAM 3.63 811 AM 5/26
STERLING NWS/WFO 2.79 812 AM 5/26

**********************12 HOUR RAINFALL**********************

LOCATION 12 HOUR TIME/DATE COMMENTS
RAINFALL OF
(INCHES) MEASUREMENT


MARYLAND

...PRINCE GEORGE`S COUNTY...
GREENBELT 2.50 809 AM 5/26

**********************24 HOUR RAINFALL**********************

LOCATION 24 HOUR TIME/DATE COMMENTS
RAINFALL OF
(INCHES) MEASUREMENT


MARYLAND

...PRINCE GEORGE`S COUNTY...
GREENBELT 4.00 809 AM 5/26

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