Friday, February 12, 2010

Gulf Coast Storm Brings Rare Heavy Snow to East Texas, Northern Louisiana

The same storm which brought record snowfall to Dallas spread heavy snow, with rates as high as 1-2" per hour in places, across east Texas and northern Louisiana. The heaviest snow was mainly north of a line from Jacksonville, Texas to Natchitoches, Louisiana. The 5.4" in Shreveport, LA was the 7th heaviest in records extending back to 1871. This was also the largest snowfall in Shreveport since December 16th, 1983. Natchitoches reported 6.0". Snow amounts in Arkansas ranged up to 5.8" in Texarkana. In Texas, reports ranged from 2.0" near Lufkin to 7.0" at Longview and 10.0" at Lindale.

Images (click to enlarge): Feb. 11-12 snowfall amounts in east Texas and northern Louisiana, Storm situation overview; from National Weather Service

Dallas Sets All-Time Calendar Day and 24-Hour Snowfall Record

PM Update: The National Weather Service map of Feb. 11-12 storm snowfall totals across north Texas shows the highest amounts along and north of highway I-20.

Noon Update: Added seasonal statistics. The Dallas Morning News reports that 170,000 customers are without power in the area.

AM Update: The final record daily snowfall for Dallas was 11.2" on Feb. 11. The 24-hour total of 12.5" from 4 am Feb. 11 to 4 am Feb. 12 also broke the 24-hour record of 12.1" on Jan. 15-16, 1964.

The seasonal total of 15.7" is now the second highest on record, and this is the snowiest winter since 1977-1978. Some comparative statistics from the National Weather Service:
DALLAS/FORT WORTH - SNOWIEST SEASONS

1 17.6 1977-78
2 15.7 2009-10*
3 15.3 1963-64
4 13.5 1923-24
5 10.4 1976-77
6 9.5 1909-10
7 9.2 1916-17
8 8.8 1947-48
9 8.1 1937-38
10 7.3 1965-66
7.3 1941-42

--------------------------------------------------------------------

DALLAS/FORT WORTH - MOST SNOW IN FEBRUARY

1 13.5 1978
2 12.5 2010*
3 7.5 1924

--------------------------------------------------------------------

DALLAS/FORT WORTH - GREATEST 24-HOUR SNOWFALL TOTALS

1 12.5 FEBRUARY 11-12, 2010*
2 12.1 JANUARY 15-16, 1964
3 8.2 JANUARY 14-15, 1917
4 7.5 FEBRUARY 17, 1978
7.5 FEBRUARY 25, 1924
6 6.0 MARCH 13, 1924
7 5.5 DECEMBER 9, 1898
8 5.0 NOVEMBER 22, 1937
5.0 JANUARY 5, 1910
10 4.7 NOVEMBER 13, 1976
The Weather Channel reports online:
After dropping record amounts of snow (just over a foot) in the Dallas Metroplex Thursday a vigorous storm is spreading a nasty taste of winter eastward along the I-20 corridor into early Saturday.

Already from Shreveport to the Mississippi-Alabama line, snowfall has been in the 3-to-8-inch range.

Heading eastward from south-central Alabama, through the Savannah River Valley, to southeast North Carolina, three to six inches of snow will be common before all is said and done. Snowfall could reach 2 to 4 inches as far north as the Atlanta metro and the rain could end as a few inches of snow in Mobile.
Original Post:
The National Service reported on Thursday, Feb. 11, that the storm moving eastward along the Gulf Coast set an all-time snowfall record for Dallas:
...RECORD DAILY MAXIMUM SNOWFALL FOR FEBRUARY 11TH SET AT DALLAS  
FORT WORTH...

THROUGH 7 PM CDT...DALLAS FORT WORTH AIRPORT HAS RECORDED 7.9 INCHES
OF SNOW. THIS BREAKS THE GREATEST CALENDAR DAY SNOW ON RECORD. THE
OLD RECORD IS 7.8 INCHES SET ON JANUARY 15...1964 AND JANUARY 14...
1917.

THIS ALSO BREAKS THE RECORD 24-HOUR SNOWFALL FOR FEBRUARY WHICH
WAS 7.5 INCHES...SET ON FEBRUARY 17...1978 AND FEBRUARY 25...1924.

OBVIOUSLY....THIS SHATTERS THE RECORD DAILY MAXIMUM SNOWFALL FOR
FEBRUARY 11TH...OF 1.4 INCHES WHICH WAS PREVIOUSLY SET IN 1988.

Thursday, February 11, 2010

Blizzard Blitz 2.0 Fed By Record Moisture Amounts

As was the case with the earlier Super Bowl storm which inundated the Mid Atlantic region with record snowfalls, the February 10 blizzard was fed by record-breaking moisture amounts. A number of locations from Pennsylvania through New Jersey, Delaware, and New York broke daily precipitation records from the storm; some dated as far back as 1881:
A RECORD WATER EQUIVALENT PRECIPITATION FOR FEBRUARY 10 OF 1.20   
INCHES OCCURRED AT THE TRENTON MERCER COUNTY AIRPORT, BREAKING THE
OLD RECORD FOR THE DATE OF 0.89 INCHES SET IN 1970.

A RECORD WATER EQUIVALENT PRECIPITATION FOR FEBRUARY 10 OF 1.50
INCHES OCCURRED AT THE READING REGIONAL AIRPORT, BREAKING THE OLD
RECORD FOR THE DATE OF 1.21 INCHES SET IN 1881.

A RECORD WATER EQUIVALENT PRECIPITATION FOR FEBRUARY 10 OF 0.90
INCHES OCCURRED AT THE ATLANTIC CITY INTERNATIONAL AIRPORT, BREAKING
THE OLD RECORD FOR THE DATE OF 0.75 INCHES SET IN 1967.

..RECORD DAILY MAXIMUM SNOWFALL SET AT WILMINGTON

A RECORD SNOWFALL FOR FEBRUARY 10 OF 7.2 INCHES OCCURRED AT THE NEW
CASTLE COUNTY AIRPORT, BREAKING THE OLD RECORD FOR THE DATE OF 5.0
INCHES SET IN 1949.

ALSO, THE WATER EQUIVALENT PRECIPITATION FOR THE DAY OF 0.90 INCHES
BROKE THE RECORD FOR THE DATE OF 0.80 INCHES SET IN 1926.

..RECORD DAILY MAXIMUM SNOWFALL SET AT ALLENTOWN

A RECORD SNOWFALL FOR FEBRUARY 10 OF 17.3 INCHES OCCURRED AT THE
LEHIGH VALLEY INTERNATIONAL AIRPORT, BREAKING THE OLD RECORD FOR THE
DATE OF 4.2 INCHES SET IN 1926.

ALSO, THE WATER EQUIVALENT PRECIPITATION FOR THE DAY OF 1.40 INCHES
BROKE THE RECORD FOR THE DATE OF 0.98 INCHES SET IN 1970.

..RECORD DAILY MAXIMUM SNOWFALL SET AT PHILADELPHIA

A RECORD SNOWFALL FOR FEBRUARY 10 OF 9.3 INCHES OCCURRED AT
PHILADELPHIA INTERNATIONAL AIRPORT, BREAKING THE OLD RECORD FOR THE
DATE OF 8.7 INCHES SET IN 1926.

ALSO, THE WATER EQUIVALENT PRECIPITATION FOR THE DAY OF 1.10 INCHES
BROKE THE RECORD FOR THE DATE OF 0.76 INCHES SET IN 1926.

A RECORD RAINFALL OF 0.92 INCHES WAS SET AT ISLIP NY YESTERDAY. THIS
BREAKS THE OLD RECORD OF 0.78 SET IN 1990.

Washington, DC Snow Video Gallery
Update: Baltimore Added

Feb. 15 Update: An urban time-lapse from Baltimore (tip of the wind vane to Maryland Weather blog):



Original post:
A tip of the wind vane to dcist for this video of the Feb. 5-6 snowstorm from two Columbia Heights residents:

Washington, DC Snow Storm from Es Video! on Vimeo.



HuffPo links to this YouTube time-lapse video of the storm:



Another time-lapse, from Tyson's Corner:

Wednesday, February 10, 2010

Monthly and Seasonal Snowfall Records Set in Pennsylvania, Delaware, New Jersey

For related posts, see:Midnight update:
February monthly and seasonal snowfall records have also been set in Pittsburgh, Philadelphia, and Atlantic City:
..RECORD FEBRUARY SNOWFALL AND RECORD TIED FOR DATE IN PITTSBURGH  

WE CONTINUE TO ADD TO THE RECORD FEBRUARY SNOWFALL. AS OF 10 PM,
TODAYS SNOWFALL MEASURED 5.2 INCHES. THIS TIES THE RECORD FOR THE
DATE, SET IN 1926.

THE STORM TOTAL IS 7.9 INCHES.

THE TOTAL FOR THE MONTH IS NOW 29.6 INCHES.

THE PREVIOUS RECORD FOR FEBRUARY WAS 25.3 IN 2003. THE NORMAL FOR
FEBRUARY IS 8.5 INCHES.

FEBRUARY 2010 NOW RANKS AS THE 6TH SNOWIEST MONTH EVER.
THE SNOWIEST MONTHS...

40.2 JANUARY 1978.
36.3 DECEMBER 1890.
34.1 MARCH 1993.
32.3 NOVEMBER 1950.
30.1 JANUARY 1994.

THE SNOWIEST SEASON ON RECORD WAS 82.0 INCHES THE WINTER OF 1950-51.
OUR SEASON TOTAL SO FAR FOR 2009-10 IS 57.8 INCHES. NORMAL FOR
PITTSBURGH IS 40.6 INCHES.

SNOWFALL RECORDS FOR PITTSBURGH DATE BACK TO 1884.


..SNOWIEST YEAR (JULY THROUGH JUNE) ON RECORD FOR ATLANTIC CITY

WITH 5.9 INCHES OF NEW SNOW IN ATLANTIC CITY THROUGH 7PM, THE SEASON
TOTAL JUMPED TO 48.7 INCHES. THIS TOTAL NOW RANKS AS THE SNOWIEST
SEASON ON RECORD, SURPASSING THE 46.9 INCHES THAT FELL IN THE
1966-1967 SEASON.

THE ELEVEN SNOWIEST YEARS (JULY THROUGH JUNE) AT ATLANTIC CITY:

RANK SNOWFALL YEARS
(INCHES)

1 48.7 2009-2010
2 46.9 1966-1967
3 46.4 1995-1996
4 43.1 1978-1979
5 42.3 2002-2003
6 38.1 1963-1964
7 37.3 1933-1934
8 33.5 1913-1914
8 33.5 1957-1958
10 32.3 1960-1961
10 32.3 1986-1987

..SNOWIEST YEAR (JULY THROUGH JUNE) ON RECORD FOR PHILADELPHIA

WITH THE 14.0 INCHES OF SNOW THAT FELL IN PHILADELPHIA THROUGH 7 PM,
THE SEASON TOTAL JUMPED TO 70.3 INCHES. THIS TOTAL NOW RANKS AS THE
SNOWIEST SEASON ON RECORD, SURPASSING THE 65.5 INCHES THAT FELL IN
1995-1996 SEASON.

THE TEN SNOWIEST YEARS (JULY THROUGH JUNE) AT PHILADELPHIA:

RANK SNOWFALL YEARS
(INCHES)

1 70.3 2009-2010
2 65.5 1995-1996
3 55.4 1898-1899
4 54.9 1977-1978
5 49.1 1960-1961
6 46.3 2002-2003
7 44.3 1966-1967
8 43.9 1917-1918
9 43.8 1904-1905
10 41.8 1957-1958
Original post:
The National Weather Service reports that monthly and seasonal snowfall records have been set in Harrisburg, PA and Wilmington, DE:
..RECORD DAILY MAXIMUM SNOWFALL SET AT HARRISBURG PA 

..RECORD FEBRUARY MONTHLY SNOWFALL RECORD SET AT HARRISBURG PA

..SECOND SNOWIEST CALENDAR MONTH OF ALL-TIME AT HARRISBURG PA

A RECORD SNOWFALL OF 10.0 INCHES WAS SET AT HARRISBURG PA TODAY.
THIS BREAKS THE OLD RECORD OF 5.2 SET IN 1970.

HARRISBURG /KMDT/ HAS OFFICIALLY REACHED 13.4 INCHES OF SNOWFALL
FOR THIS STORM...MAKING THE MONTHLY TOTAL 34.5 INCHES. THIS SETS
A NEW ALL-TIME FEBRUARY SNOWFALL RECORD...BREAKING THE PREVIOUS
RECORD OF 30.3 INCHES...SET BACK IN 1893.

TOP 5 SNOWIEST FEBRUARYS FOR KMDT...
34.5 IN 2010 AND COUNTING
30.3 IN 1893
30.2 IN 1964
29.8 IN 2003
28.8 IN 1983

INTERESTINGLY...THIS COMES ONE YEAR AFTER FEBRUARY 2009 TIED FOR THE
5TH LEAST SNOWIEST FEBRUARY ON RECORD AT HARRISBURG...WITH A
TOTAL OF ONLY SEVEN TENTHS /0.7/ OF AN INCH OF TOTAL SNOWFALL.

THIS CALENDAR MONTH IS NOW THE SECOND SNOWIEST CALENDAR MONTH
OF ALL-TIME IN HARRISBURG.

TOP 5 SNOWIEST CALENDAR MONTHS AT KMDT...
38.9 IN JAN 1996
34.5 IN FEB 2010 SO FAR
34.2 IN JAN 1994
34.0 IN JAN 1961
33.5 IN JAN 1978


...SNOWIEST YEAR ON RECORD (JULY THROUGH JUNE) SET IN WILMINGTON,
DELAWARE...

WITH THE 9.8 INCHES OF SNOW THAT FELL IN WILMINGTON THROUGH 1 PM,
THE SEASON TOTAL JUMPED TO 63.7 INCHES. THIS TOTAL NOW RANKS AS THE
SNOWIEST SEASON ON RECORD, SURPASSING THE 55.9 INCHES THAT FELL IN
1995-1996 SEASON.

THE TEN SNOWIEST YEARS (JULY THROUGH JUNE) AT WILMINGTON:

RANK SNOWFALL YEARS
(INCHES)

1 63.7 2009-2010
2 55.9 1995-1996
3 49.5 1957-1958
4 46.0 2002-2003
5 45.6 1977-1978
6 44.7 1933-1934
7 44.7 1906-1907
8 44.2 1978-1979
9 44.1 1960-1961
10 43.5 1966-1967

111-Year-Old Washington Snow Record Falls at 2 PM, 2-10-10
Record Amount Extended

For related posts, see:Midnight Update February 10 daily/February monthly/2009-2010 seasonal total snowfall amounts and current snow depth on the ground as of midnight:
Washington National 7.1"/31.9"/55.9"/17"
Washington Dulles 9.3"/47.9"/75.0"/26"
Baltimore BWI 15.5"/49.2"/79.9"/21"
Evening Update, 7:00: Latest 6 hour total/24 hour total/snow depth on ground:
Washington National 2"/9"/22"
Washington Dulles Trace/8"/27"
Baltimore BWI Not available
PM Update, 4:45: February 10 daily/February monthly/2009-2010 seasonal total snowfall amounts and current snow depth on the ground:
Washington National 6.8"/31.6"/55.6"/20"
Washington Dulles 6.3"/44.9"/72.0"/27"
Baltimore BWI 12.9"/46.6"/77.3"/28"
PM Update, 3:00: The National Weather Service reports:
...PRELIMINARY ALL-TIME SEASONAL SNOWFALL RECORDS SET AT THE  
THREE MAJOR CLIMATE SITES IN THE BALTIMORE-WASHINGTON AREA...

AS OF 2 PM TODAY...WITH THE 9.8 INCH TWO-DAY SNOWFALL TOTAL MEASURED
AT RONALD REAGAN WASHINGTON NATIONAL AIRPORT...THE SEASONAL SNOWFALL
TOTAL IN WASHINGTON DC STANDS AT 54.9 INCHES. THIS WOULD BREAK THE
PREVIOUS ALL-TIME SEASONAL SNOWFALL RECORD FOR WASHINGTON DC OF 54.4
INCHES SET IN THE WINTER OF 1898-99. OFFICIAL SNOWFALL RECORDS FOR
WASHINGTON DC DATE BACK 126 YEARS TO 1884.

AS OF 1 PM TODAY...WITH THE 11.9 INCH TWO-DAY SNOWFALL TOTAL
MEASURED AT BALTIMORE/WASHINGTON INTERNATIONAL THURGOOD MARSHALL
AIRPORT...THE SEASONAL SNOWFALL TOTAL IN BALTIMORE STANDS AT 72.3
INCHES. THIS WOULD BREAK THE PREVIOUS ALL-TIME SEASONAL SNOWFALL
RECORD FOR BALTIMORE OF 62.5 INCHES SET IN THE WINTER OF 1995-96.
OFFICIAL SNOWFALL RECORDS FOR BALTIMORE DATE BACK 118 YEARS TO 1893.

FINALLY...AS OF YESTERDAY...THIS YEARS SEASONAL SNOWFALL TOTAL AT
DULLES INTERNATIONAL AIRPORT STOOD AT 63.5 INCHES. THIS WOULD BREAK
THE PREVIOUS SEASONAL SNOWFALL RECORD OF 61.9 INCHES SET IN 1995-96.
AS OF 1 PM THIS AFTERNOON...THE TWO-DAY SNOWFALL TOTAL AT DULLES IS
8.5 INCHES...WHICH WOULD MAKE THIS YEARS SEASONAL SNOWFALL TOTAL
72.0 INCHES. OFFICIAL SNOWFALL RECORDS FOR DULLES DATE BACK 48 YEARS
TO 1962.
PM Update, 2:00: At 2 pm, Washington National is reporting another 1" of new snow. Unofficially, this raises the seasonal total to 54.8", erasing a record which has stood since the winter of 1898-99. (Chart has been updated accordingly.) Total depth on the ground is 21".

BWI also reports an additional 1", bringing the depth on the ground to 29".

PM Update, 1:25: A National Weather Service Public Information Statement confirms a storm total so far of 8.7". This raises the seasonal total to 53.8", just 0.6" less than the all-time record seasonal total.

Dulles is at 8.5" and BWI at 11.9".

PM Update, 1:00: Washington National added one more inch in the past hour with heavy snow still falling. Unofficially, this is within less than 1" of the all-time seasonal record. Total depth on the ground of 20" is up 3" from this morning and 7" from yesterday.

Noon Update: Washington National added another 1" in the past hour.

Feb. 10 AM Update: Storm totals as of 7 am:
Washington National 5.1"
Washington Dulles 4.0"
Baltimore BWI 5.2"
This pushes the Washington seasonal total to just over 50". Unofficially, National has added 2 more inches through 11 am. If confirmed, Washington will be within less than 3" of the all-time seasonal record.

Original post:
The 3.7" of new snowfall as of midnight brings the official Washington, DC seasonal total to 48.8", moving this season ahead of 1995-96 into second place. This winter is now less than 6" away from the all-time Washington seasonal snowfall record set in 1898-99.

The February total of 24.8" still remains in 4th place, however, behind 2003.

With the snow having changed to freezing rain for the last couple of hours, accumulations overnight will likely be reduced from earlier expectations.

Monday, February 8, 2010

Welcome Weather Underground Visitors
Some Further Thoughts on Super Storm 2010

For related posts, see:

Welcome Wundergrounders, and thank you Jeff Masters for your generous compliment. I've been a fan of Weather Underground since the earliest days of the WWW. Along with UIUC Weather World, it was one of my first bookmarks on Netscape 0.5.

I'd like to take this opportunity to endorse Dr. Masters' commentary on the relative significance of moisture and temperature in monster winter events and try to expand the discussion a bit. Every individual weather event is unique in its own way, and extreme events, by definition, are even more unique; otherwise, they wouldn't be rare. However, there are also a lot of similarities. In these days of increasingly accurate computer models (and this latest event was very well captured as much as 6 days out), it may seem old-fashioned, but looking at analogs, or similar situations from the past, can be very instructive. Considering the historic nature of this storm, I went back and looked at the weather maps for the other record February snowstorms of the past century in Washington. Overall (and somewhat simplified), the basic elements and their evolution were very similar to what we've all come to expect from these situations:
  • a low pressure area generally originating in or near the Gulf of Mexico, moving northeastward and then deepening rapidly off the Mid Atlantic coast
  • a blocking cold high pressure area to the north
  • another deep low pressure area to the northeast helping to anchor the high in place
These things are all very well documented and in more more detail in Kocin and Uccellini's now-classic books. One thing that really struck me in comparing these, however, was the big difference in the intensity of the cold air to the north. The other cases all had extremely cold surface temperatures in northern New England and southeastern Canada, frequently in the -20°F to -40°F range. That was not true in this case. As Dr. Masters explained, once all the other elements are in place, it doesn't need to be ultra cold in order to snow, just cold enough.

Take a look at the 12Z (7 am EST) surface map for Saturday, Feb. 6. All the right elements are there, including a honking deep 986 mb low parked near the mouth of the Chesapeake Bay, and heavy snow is pummeling the Nation's Capital. Temperatures to the north are cold, of course, but the 0° line is way out of the U.S. Single digits extend from Maine across northern New England and into Quebec. Below-zero readings are confined to central and western Ontario, too far west to be feeding into this storm.

Now consider the 12Z map closest to the heaviest snow for the 2003 event, Feb. 17. The zero line (blue dash-dot) goes from northern Nova Scotia across the northern third of Maine (-22° at Houlton), along the Canadian border and encompasses nearly all of Quebec and eastern Ontario.

In 1983, the low development is less advanced at 12Z on Feb. 11, but the freezer is working overtime to the north. The zero line (black dash-dot) takes in essentially all of New Brunswick, Maine, New Hampshire, Vermont, about half of New York, Quebec, and eastern Ontario. Peak cold, as plotted, is -26° to -27°.

For the President's Day storm of 1979, the Feb. 19 map shows all the usual suspects, although the orientation of the high is somewhat different. Temperature-wise, however, the zero line cuts across a large chunk of New England (-18° at Houlton), northeastern New York, all of Quebec, and most of Michigan. Readings in the -20° range are widespread.

The Feb. 7, 1967 picture shows a little less extent for the 0° intrusion into New England, but Earlton, Ontario checks in with -33°, and Armstrong sports a mercury-freezing -39° and an unmeasurable dewpoint.

Feb. 16, 1958? Armstrong is back with its frozen instrument, and Pagwa plays "Can you top this?" with -40°.

On Feb. 7, 1936, the U.S. has embarrassingly not yet embraced the polar front theory of analysis, but the icebox is stoked with -20° to -40° temperatures.

The conclusion I would draw from all of this is that the 2010 storm was distinct from other similar events in the past by having moisture be the dominant element over temperature in producing the extreme snow amounts.

Images (click to enlarge): Surface weather maps at 12Z (7 am EST) from National Weather Service for major Washington, DC February snowstorms (top to bottom):
  • Feb. 6, 2010
  • Feb. 17, 2003
  • Feb. 11, 1983
  • Feb. 19, 1979
  • Feb. 7, 1967
  • Feb. 16, 1958
  • Feb. 7, 1936

Sunday, February 7, 2010

Seasonal Snow: Rewriting Records

For related posts, including the latest record report, see: 6 PM Update: Added chart of all-time top individual storms. As noted earlier, the storm of Feb. 5-6, 2010 is now the 4th biggest of all time in Washington and the 2nd biggest at Washington National.

Original post:
This weekend's epic 17.8" snowstorm in Washington has rewritten the top 10 lists for individual storms, as well as February and seasonal snowfalls with only 1 week elapsed in the month. This month's 21.1" to date just edges out the 21" in 1983 to take fourth place.

In the seasonal ranks, the 45.1" reported so far displaces the 1921-22 season and its infamous Knickerbocker storm out of the number 3 slot. With more snow expected in the middle of the week, the second place record of 1995-96 is in serious jeopardy.

Images (click to enlarge): Washington, DC biggest snowstorms of all time, highest February and seasonal snow totals, CapitalClimate charts from National Weather Service data

Seasonal Outlook

Latest seasonal forecast: Click here.


Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.