Snow in March?

March snow in the DC Metro Region  (March 4, 2016)

Although less common than in January and February, Washingtonians do see snow during March.  National Weather Service data indicates that the Nation’s Capital averages 1.3 inches of March snow.  In fact, above average snowfall has occurred during three of the last four years in the Nation’s Capital.

March is a transitional weather month with a big change in daily average temperatures in Washington, D.C.  The average high on March 1 is 51 degrees, while it climbs to 61 degrees by March 31.  There’s also an increased amount of daylight: sunrise and sunset on March 1 are 6:38 AM / 6:02 PM, while on March 31 they are 6:52 AM / 7:31 PM.  These elements conspire to make significant snowfall in the Nation’s Capital relatively rare in March.

Just two years ago, Washingtonians had a snowy St. Patrick’s Day and with a total of 12.7 inches, March 2014 was the snowiest March since 1960.  It was also the snowiest March on record at Dulles Airport where 19.8 inches accumulated.  Large temperature fluctuations are also common in March shortly before or after it snows.  For example, on March 15, 2014, the high at National Airport was 70 degrees and the snow began falling on the evening of March 16.  According to the National Weather Service, it was back up to 61 degrees on March 20, 2014 – just three days after the 7.2 inches of snow concluded.  So while March snowfall can be significant, it doesn’t usually last long because of the changeable weather.

Washington, D.C.’s largest March snowstorm on record came on March 27 – 28, 1891 when 12.0 inches occurred.  The largest March snowfall since National Airport opened in June 1941, was when 11.5 inches accumulated on March 28 – 29, 1942.  When the 7.2 inches fell on March 16 – 17, 2014, that became the tenth largest March snowfall on record in the Nation’s Capital – and bumped to the “Superstorm of 1993” (that brought Washington, D.C. 6.6 inches of snow) to number eleven.

Although this month has been 8.6 degrees warmer than average through March 18, the next few days will be more winter-like with temperatures falling through the 40s this afternoon and highs only in the 40s tomorrow and Monday.  That’s following yesterday’s high temperature of 67 degrees and is also ironic because tomorrow is the vernal equinox and first official day of spring.  Most of the DC Metro Region with see some snow this afternoon continuing into tomorrow in spots.  Slushy accumulations are possible in grassy areas and on rooftops primarily west and north of town.  However, roads should remain just wet since ground temperatures are well above freezing.  Follow my colleagues and me on the WUSA9 weather team for the latest weather updates.

Status of Recovery in Cabo San Lucas

Odile making landfall near Cabo San Lucas in September 2014  (Source: NOAA)

The eastern Pacific Ocean has seen an uptick in tropical storm formation during the last two years with a concurrent stretch of below average tropical activity in the Atlantic Ocean Basin.  That has manifested itself in a variety of ways on both sides of North America.  Mexico has seen more rain and flooding from tropical systems during the last two seasons in particular while the Atlantic Ocean Basin has had less.

Last season Hurricane Patricia became the most intense hurricane on record in the Western Hemisphere.  Patricia was a Category 5 hurricane that had 215 mph sustained winds at peak intensity and made landfall along the west coast of Mexico as a Category 5.  Meanwhile, the United States hasn’t had a major hurricane – Category 3 or higher – make landfall since 2005.  Although it didn’t have a direct impact on the United States, last season’s Hurricane Joaquin was a powerful Category 4 storm and was the strongest Atlantic storm since 2010. 

During the 2014 eastern Pacific hurricane season, an intense hurricane took an unusual track.  At peak intensity, Odile was a Category 4 hurricane on the Saffir-Simpson Hurricane Intensity Scale with sustained winds of 140 mph (on September 14, 2014).  Although, Odile weakened slightly to a Category 3 hurricane before making landfall with sustained winds of 125 mph, it was the strongest hurricane to make landfall on the southern tip of Baja California in more than forty years.  

Odile caused significant damage to the Mexican resort town of Cabo San Lucas.  According to the National Hurricane Center, Odile claimed 11 lives and caused roughly $1 billion in damage.  I was in Cabo San Lucas roughly two months later in late November 2014, and observed first-hand areas of widespread damage to both infrastructure and the local ecosystem.  In Cabo San Lucas for a few days again this week, I have had the chance to talk with some area residents who have confirmed what I observed, the resort town has largely recovered from Hurricane Odile.  

Some area resorts said they utilized stricter building codes when they rebuilt, ensuring property would be more resistant to damage in the rare event another major hurricane threatens the area.  Most hurricanes in the eastern Pacific Ocean track westward or curve back into mainland Mexico.  Tropical storms are rare and hurricanes even rarer still in Cabo San Lucas.  Fortunately, hurricane season is still several months off in both the Atlantic and eastern Pacific Ocean Basins. So there is plenty of time to review what you would do if a tropical system threatens your area.  As Odile illustrated, it only takes one storm to have a significant impact so it’s important to listen to your favorite meteorologists and local authorities whenever a tropical system approaches.

Significant March Weather: Past and Present

"Superstorm" Snow Accumulations

Weather enthusiasts often love March because of its high degree of changeability that can include heavy snow, severe weather and wide swings in temperature from extreme cold to spring and summer-like warmth.  Such has been the case so far this month with both measurable snowfall and record warmth occurring in the Nation’s Capital. 

One of the most powerful coastal storms on record in the eastern United States also happened to be wrapping up on this date 23 years ago.  Dubbed the “Superstorm of 1993,” it brought record snowfall, severe weather and records for lowest observed air pressure to cities and communities from Florida to Maine.  Snow fell in the “Superstorm of 1993” as far south as Alabama and Georgia – including in the Nation’s Capital.  Although this storm brought Dulles Airport 14.1 inches of snow, only 6.6 inches accumulated at National Airport.  That’s because the snow changed to sleet at National Airport during the height of the storm (that reduced accumulations).  

Another major facet of the storm was the damaging severe weather that occurred across central Florida that included 11 confirmed tornadoes.  At peak intensity, the storm's air pressure was the equivalent of a Category 3 hurricane.  Consequently, the National Climatic Data Center noted a number of cities from Georgia to New York set new records for lowest observed air pressure.  Standard sea level air pressure is approximately 29.92 inches of mercury (1013 millibars) while Washington, D.C. had a record air low pressure of 28.54 inches of mercury (966.5 millibars).  

Although this month hasn’t featured anything as widespread or damaging as the 1993 “Superstorm”, Washingtonians have experienced some memorable weather over the last two weeks.  The first few days of March were colder than average with measurable snowfall on March 4 at the three area airports, Reagan National, Dulles and BWI-Marshall.  Temperatures have otherwise been warmer than average on all but four days this month in the Nation’s Capital.  Record warmth occurred on March 9 and March 10 in the Mid-Atlantic Region but no record warmth is on tap this week.

Nevertheless, NOAA’s outlook for above average March temperatures across much of the central and eastern United States was accurate.  There have been some other notable weather headlines this month including deadly flooding from Texas to Tennessee along with much-needed rainfall and mountains snows in the Pacific Northwest and central to northern Rocky Mountains.

Notable “Superstorm of 1993” Snow totals (March 12 – 15, 1993):

Mount Mitchell, NC – 50”
Snowshoe, WV – 44”
Syracuse, NY – 43”
Lincoln, NH – 35”
Albany, NY – 27”
Pittsburgh, PA – 25”
Mountain City, GA – 24”
Chattanooga, TN – 20”
Portland, ME – 19”
Roanoke, VA – 16”
Birmingham, AL – 15”
Boston, MA – 9”
Atlanta, GA – 4”

This post was filed from Cabo San Lucas, Mexico where I am looking into some local weather and climate issues for a few days.

The First Heat Wave of 2016

Some Washingtonians might feel a little chilly today as high temperatures reach “only” the upper 60s and low 70s.  Although temperatures like that are more characteristic of mid-April than mid-March, they are 10 to 15 degrees cooler than Mid-Atlantic residents have enjoyed during the last three days.

No one will complain, though, as today’s highs temperatures will be well above the average high of 54 degrees.  In fact, yesterday’s low temperature at National Airport was a balmy 57 degrees.  High temperatures the last three days have been around 80 degrees in the Washington, D.C. – Baltimore corridor – setting multiple records.  According to the National Weather Service, the warmest temperature measured downtown was 79 degrees, which isn’t the “average” high temperature in the Nation’s Capital until May 28. 

                        

Today will be the fifth consecutive day that high temperatures exceed 65 degrees in Washington, D.C.  The speed at which temperatures have warmed up in the last week has been rather remarkable.  For example, a record tying 0.6” of snow fell at Dulles Airport last Friday, March 4.  Just yesterday Dulles Airport broke a 16-year old record high when it was 82 degrees (82 degrees is their average high temperature on June 8).

Another thing that’s made this month especially unusual is that a weather pattern more characteristic of late spring or early summer has set up across much of the eastern United States.  A sprawling area of high pressure situated off the east coast has acted like a heat pump ushering in warmer and more humid air than is typical for March.  This dominant area of high pressure has also acted as a blocking mechanism that’s caused heavy rain to linger over the same places in the central U.S. – causing deadly flooding from Texas to Kentucky.

So far this month, there have been three days of temperature greater than 70 degrees downtown – as many such days as there were during all of March last year.  When the temperature reached 79 degrees at National Airport yesterday, that was the warmest March temperature in Washington, D.C. since 2012.  As was the case in 2012 when the Cherry Blossoms along the Tidal Basin reached their peak bloom on March 20, the National Park Service expects similar results this year given the above average temperatures.  They updated their earlier forecast and now expect peak bloom to occur between March 18 and March 23.

New Record Highs Set this Week:

March 9

Dulles Airport (IAD), Sterling, VA: 82 degrees
Baltimore, MD (BWI Airport): 82 degrees

March 10

Washington, D.C. (National Airport, DCA): 79 degrees
Dulles Airport (IAD), Sterling, VA: 80 degrees
Baltimore, MD (BWI Airport): 80 degrees