DC's frightful Halloween forecast

 

Getting ready for Halloween

October 2023 has been a warm and dry month in the nation’s capital.  However, Halloween will feel more like November than the September-like warmth in the 70s and 80s Washingtonians have experienced the last few days.  Check out this feature I wrote for the WUSA9 website for details.

Hurricane Otis: A Story of Rapid Intensification

 

Hurricane Otis at landfall (Source: WUSA9)

Hurricane Otis broke a slew of records when it made landfall near Acapulco, Mexico earlier this week.  It grew from a tropical storm to a Category 5 hurricane in a matter of hours and that rate of intensification is almost unprecedented.  Check out this article I wrote for the WUSA9 website for details.

DC’s winter weather outlook

 

Could DC's 2023-24 winter be snowy ? (Photo Credit: Lee Laudicina)

The nation’s capital averages 13.7” of snowfall annually, according to NOAA.  Sometimes it comes in a series of smaller storms as it did during the 2014-2015 winter season.  In other winters, it occurs primarily during one large storm such as during the 2015-2016 winter.  NOAA recently released its winter weather outlook, and my colleagues and I on the WUSA9 weather team will release ours soon. 

There are a lot of factors to consider such as the status of the El Nino Southern Oscillation, “ENSO,” which refers to the presence of El Nino, La Nina or a neutral phase, meaning the presence of neither.  It’s also important to consider the status or “phase” of the North Atlantic Oscillation (“NAO”). 

There have been a number of memorable winter seasons that could offer clues as to what might be in store for the 2023-2024 season in the DC Metro Area.  Four of the last 10 winters have been snowier than average in Washington, D.C., but none since 2018-2019.

Sometimes winter arrives early as it did during the 1989-1990 season.  November 1989 was 1.6° cooler than average in the nation’s capital and saw 3.5” of snow (seven times the monthly average).  Meanwhile, December 1989 was an astounding 11.8° colder than average in the nation’s capital, making it DC’s coldest since 1917.  A total of 12.5” of snow fell during those two months.  However, the weather pattern changed dramatically to being significantly warmer than average when January arrived.  A combined total of only 2.6” of snow fell from January 1 through March 31, 1990.  That was an ENSO neutral winter.

On the opposite end of the spectrum was the 2015-2016 winter season.  December 2015 was DC’s warmest on record.  The first measurable snowfall of the winter didn’t occur until 0.3” fell on January 17, 2016.  Less than a week later, DC residents experienced one of the largest snowstorms on record with a total of 17.8” on January 22-23.  The rest of the 2015-2016 winter season was unremarkable and DC had a seasonal snow total of 22.2”.  A particularly strong El Nino occurred that winter and was a contributing factor in the 2015-2016 winter weather events.

By comparison, the 2014-2015 winter season had a weak episode of El Nino and DC saw a series of smaller snowstorms.  At least 0.1” of snow fell on 14 days between January 1 and March 31, 2015, with a seasonal snow total of 18.3”.  Unlike the 2015-2016 winter when over 80% of the snow occurred during the record January 2016 storm, the largest daily snowfall of the 2014-2015 winter season was 4.8” on March 5, 2015.

NOAA’s winter weather outlook calls for warmer and wetter than average conditions in the Mid-Atlantic Region.  That’s fairly typical for an El Nino winter and snow-lovers shouldn’t fret since the right ingredients only have to come together once to produce a large snowfall.  That’s what happened during the 2015-2016 winter season which got off to a record warm start in December and didn’t see any measurable snowfall until mid-January.  Most of DC’s snowiest winters since 1950 have been El Nino winters, including such memorable winters as 2002-2003 and 2009-2010.

Significant late October Atlantic hurricanes

 

Hurricane Wilma, October 2005 (Source: NOAA)

Although not as active as September typically is, October can still be quite active in the tropical Atlantic.  However, the frequency and intensity of tropical storms and hurricanes often decreases as the month of October wears on. 

That’s not to say there haven’t been high impact hurricanes in late October.  Some of the costliest hurricanes have made landfall in the United States during the second half of October, as described below. 

Zeta (2020) – The fifth major hurricane of the record-setting 2020 Atlantic hurricane season, Zeta reached its peak intensity on October 28 as a Category 3 storm.  Zeta made landfall in Louisiana at peak intensity with 115 mph sustained winds.  It was one of three 2020 hurricanes to make landfall in Louisiana.  Zeta did an estimated $5.1 billion in damage (2023 dollars), according to NOAA.

Sandy (2012) – The strongest hurricane of the 2012 season, Sandy reached Category 3 intensity with sustained winds of 115 mph.  It tracked north after its landfall in Cuba on October 25.  It made landfall as a weaker storm in New Jersey, and caused extensive coastal flooding with significant impacts that reached well-inland as well as devastating New York City and Long Island, New York.  Sandy also set a number of rainfall and low pressure records. 

Shortly before its landfall in New Jersey, Sandy lost its tropical characteristics over cooler ocean waters and was declared a non-tropical or “post-tropical” storm by the National Hurricane Center.  Consequently, all the hurricane watches and warnings were discontinued.  That led to a lot of confusion since many people mistakenly thought the storm was no longer dangerous.  As a result of this controversy, it was determined that hurricane watches and warnings should remain in effect even after a given storm becomes a non-tropical system in the future. 

Despite not officially being a tropical storm or hurricane at its time of landfall in the United States, the name “Sandy” was retired since it was both damaging and deadly.  Sandy remains the fifth costliest hurricane/former hurricane to make landfall in the United States with a price tag of $86.5 billion (2023).

Wilma (2005) – Fortunately, Wilma weakened significantly from its peak intensity as a Category 5 hurricane before it reached southwest Florida on October 24 as a Category 3 storm.  Wilma was noteworthy for being the last hurricane to make landfall anywhere in Florida until Hermine in 2016.  It produced $29.3 billion in damages (2023), placing it among the Top 15 costliest U.S. hurricanes. 

Kate (1985) – Kate reached peak intensity in the Gulf of Mexico on November 20 with sustained winds of 120 mph and a minimum central air pressure of 953 mb.  It weakened slightly to a Category 2 storm before making landfall in the Florida Panhandle on November 21.  Kate remains notable for being the latest landfalling hurricane on record in the contiguous United States.  It was also the fourth hurricane to impact the U.S. Gulf Coast during the 1985 season.