Feeling Like Summer?

 

 

The Nation’s Capital had an exceptionally cool and wet first half of May.  As of May 16, Washington, D.C. had 4.15” of rain.  It’s rained on 10 days so far this month and that’s added to a gloomy feeling.  D.C.’s monthly average temperature over the first half of the month is 2.0° below average. 

There have been some milder days recently.  However, that followed some March-like weather when highs remained in the 50s on May 7-8.  The Nation’s Capital has averaged only one May day with highs in the 50s over the last 30 years, so having two consecutively is rare.

The chilly weather early in the month coincided with very rainy weather.  The wettest days this month were May 6-7 that produced a two-day total of 2.29” at Reagan National Airport.  Scattered showers and thunderstorms the last two days added to the monthly total of 4.15” so far.  That’s 2.14” above average through May 16. 

Last night’s cold front led to today’s mostly sunny and stellar weather with lower relative humidity levels.  D.C. Area residents will also get their first taste of summer later this week as highs should reach the low 90s on Friday and Saturday.  It hasn’t been 90° in Washington, D.C. since September 15, 2021.  D.C.’s warmest temperature so far in 2022 occurred on April 13 (86°).

Washington, D.C. has averaged between one and two days of 90°/+ during the month of May since the early 1990s. There were seven such days in May 2015 (D.C.’s warmest May on record).  Conversely, May 2020 was D.C.’s coolest May since 2005 and didn’t have any 90° heat.  It would take several days of 90° heat to offset how cool the first half of this month was if May 2022 were to finish as a warmer than average month.

NOAA’s Climate Prediction Center expects near average temperatures for the D.C. Metro Area once this brief period of summer-like heat at the end of the week is over.  That would give the Nation’s Capital a near average amount of 90° May heat, but would do little to make up for the cool start to the month.  However, having one or two days of 90° heat would give Washingtonians a much-needed early taste of summer.

Weather Quiz

 

Glen Echo Park, Glen Echo, Maryland

True or False.

May is the wettest month of the year, on average, in Washington, D.C.

 

Getting Ready for the Hurricane Season

 

Ocean City, Maryland (Photo Credit: Ashley Adams)

The Atlantic hurricane season officially gets underway on June 1.  That means April and May are the ideal time to make the necessary preparations should you live in an at-risk area.  Areas of the United States that are at risk include anywhere along the coastline from Texas all the way to Florida and up the east coast.

It’s important to remember that areas well inland can also see significant impacts of tropical systems.  Hurricane Ivan made landfall along the U.S. Gulf Coast in September 2004 and its remnants brought heavy rain and severe weather (including tornadoes) to the Mid-Atlantic Region.  More recently, Hurricane Florence in September 2018 brought significant flooding to not just the Carolinas but inland areas such as Tennessee, West Virginia and Virginia. 

Hurricanes Ivan and Florence were intense Category 5 and Category 4 storms, respectively, over the open ocean.  Both weakened considerably before they made landfall.  That underscores how a hurricane doesn’t have to be an intense storm to have significant impacts once it makes landfall.  

A system doesn’t have to be a hurricane to have significant inland impacts.  One of the costliest storms in U.S. history was Tropical Storm Allison, the first named storm of the 2001 Atlantic hurricane season.  It was officially named by the National Hurricane Center on June 4 and made landfall in Texas shortly thereafter.  A slow-moving system, Allison caused severe flooding in Texas and Louisiana, as well as areas east and north of there.  Houston, Texas was especially hard-hit. 

It wasn’t until Hurricane Harvey in 2017 that many of the Texas flooding records associated with Allison were broken.  However, Allison was rare for being such a high impact system so early in the season.  It remains the first of only two tropical storms to have its names retired by the World Meteorological Organization for being destructive and/or deadly (plus Erika, 2015).  That illustrates how a tropical system doesn’t need to be a hurricane to have major impacts. 

The majority of systems that develop early in the season are weaker than those that develop later.  There is a smaller geographic area that has favorable environmental conditions for tropical storm formation earlier in the season (e.g. warm ocean water of at least 80° Fahrenheit to a depth of at least 200’, a lack of wind shear or winds that change direction with height) compared to later in the season.  That’s why June and July don’t see as much tropical activity as August and September when conditions are more favorable.

However, the climatologically favored areas for tropical storm formation early in the season are closer to the United States than later in the season.  Most early season storms that develop are in the Gulf of Mexico or in the Caribbean Sea.  Since they develop closer to land there is the increased potential of land impacts in the United States, despite the early season storms not being as strong.  How to make advance preparations will be explored in an upcoming blog post.  The first named “Atlantic” storm of 2022 will be Alex.