A closer look at Isaias and other “I” named storms

 

Hurricane Isaias forecast track from NOAA

Hurricane Isaias is the first Atlantic hurricane in nearly a year. That’s made October 8 the latest on record the first Atlantic hurricane has developed. Isaias could become a strong Category 2 storm or minimal Category 3 hurricane as it heads towards the U.S. Gulf Coast.

2026: This is the second time Isaias has been a named storm in the Atlantic. It is the first hurricane since Melissa last October in what has been an historically quiet season. Isaias will have major impacts in the United States not only where it makes landfall, but in areas well inland. Coastal areas will see storm surge flooding, beach erosion and lots of heavy rain. Inland areas will also see heavy rain and flood potential as the storm weakens.

2020: Despite being the ninth named storm of the season, Isaias was only the second hurricane. 2020 was the first time an Atlantic storm was named “Isaias.” It was a Category 1 storm at peak intensity with winds of 90 mph and a minimum central air pressure of 986 millibars (mb). By comparison, standard sea level air pressure is 1013 mb.

The 2020 version of Isaias made landfall in North Carolina on August 4 at peak intensity. It had significant impacts in the DMV (DC, Maryland and Virginia) where record rainfall occurred along with a series of tornadoes. 

2008: Hurricane Ike was a long-lasting storm that occurred during the height of hurricane season in September. At peak intensity, Ike was a powerful Category 4 storm with sustained winds of 145 mph and a minimum central air pressure of 935 mb. Although it made its final landfall in Texas as a weaker Category 2 storm, its large wind field not only caused significant coastal flooding but also impacted areas well inland with driving rainfall, wind damage, and tornadoes. 

Having caused $43.2 billion in damages according to NOAA (in 2024 dollars), Ike was the costliest US hurricane since Katrina in 2005. Ike remained the costliest storm to make landfall in the United States until Sandy in 2012. The name “Ike” was subsequently retired and replaced by the name “Isaias.”

2002: Isidore made several destructive and deadly landfalls during its trek through the Caribbean Sea in September. At peak intensity, Isidore was a major Category 3 hurricane with sustained winds of 125 mph. However, it made its final landfall as a weaker tropical storm in Louisiana on September 26. The name was retired largely due to its destructive path through the Caribbean and was replaced with the name “Ike” for the 2008 season.

How wet can October get?

 

An October day in suburban Washington, D.C.

The nation’s capital just finished another rainy and gloomy weekend. However, unlike some past October’s, none of this weekend’s rainfall was particularly heavy. Here are some hazardous October rain events in the DMV (DC, Maryland and Virginia).

2021: The first three and a half weeks were very dry with a combined rainfall total of only 0.42”. However severe weather occurred on October 25, with a cold front following highs in the 80s. A coastal storm developed a few days later that brought additional heavy rain on October 29. Consequently, October 2021 finished as a wetter than average month.

October 25:  DCA – 1.55” / IAD – 2.42” / BWI – 1.96”
October 29:  DCA – 1.15” / IAD – 1.32” / BWI – 3.01”

2019: This October remains DC’s ninth wettest on record and wettest of the last 20 years with a monthly total of 6.66”. There were four days with at least an inch of rain in the nation’s capital. Although none of the totals were record-setting at National Airport, two of the four days produced rainfall records at Dulles Airport in northern Virginia. It was DC’s second wettest Halloween. These four days also accounted for more than 80% of the monthly rainfall totals at both National and Dulles Airports (5.97”).

October 16: DCA – 1.35” / IAD – 1.04” / BWI – 1.29”
October 20: DCA – 1.60” / IAD – 1.44” / BWI – 1.35”
October 27: DCA – 1.48” / IAD – 1.29” / BWI – 1.27”
October 31: DCA – 1.25” / IAD – 1.35” / BWI – 0.98”

2012: Hurricane Sandy was the strongest storm of the 2012 season and had disastrous impacts after its landfall as a “post-tropical” storm. It caused extensive coastal flooding and resulted in fatalities from the Caribbean to Canada. Sandy also set a number of rainfall and low pressure records. DC’s three area airports had daily rainfall records on October 29, including the wettest October days on record at Dulles and BWI Airports.

October 29: DCA – 3.85” / IAD – 4.26” / BWI – 5.51”
October 30: DCA – 0.84” / IAD – 1.00” / BWI – 0.92”

2005: Following DC’s driest September in 2005 with only 0.11”, the nation’s capital had its wettest October on record the following month with 9.41”. The same was true at Dulles Airport (0.15” in September 2005 to 9.22” in October 2005). That was largely due to two consecutive days with daily rainfall records at both National and Dulles Airports. The remnants of Tropical Storm Tammy combined with a slow moving cold front to bring widespread flooding to the Mid-Atlantic Region. 

October 7:  DCA – 3.63” / IAD – 3.50”  
October 8:  DCA – 3.67” / IAD – 2.79”

October’s summery start is about to change

 

An early October day in Washington, D.C.

October is the second of three months of meteorological fall and often features some of the finest weather of the year with mild days and cool, crisp nights. Average daily high/low temperatures in the nation’s capital range from 75°/58° on October 1 to 64°/46° on Halloween.  

DC’s warmest October temperature on record of 98° occurred on October 2, 2019. Eight of the last 10 Octobers have been warmer than average in Washington, D.C. Meanwhile, DC’s coolest October temperature of 26° has occurred twice, most recently on October 31, 1917. Temperatures at or below freezing in October are quite rare in the nation’s capital with none since October 20, 1992 (32°).

The nation’s capital averages 3.66” of October rainfall. However, eight of the last 10 October’s have been drier than average. Weakening tropical systems can sometimes impact the DMV (DC, Maryland and Virginia) in October with heavy rain and severe weather. Such was the case with the remnants of Hurricane Opal in 1995 and post-Tropical Storm Sandy in 2012.

Washingtonians can sometimes get an early taste of winter with light October snowfall. A trace of snow (too little to measure) does occasionally occur, with the most recent being in 2011. The earliest in the fall season the nation’s capital has experienced accumulating snowfall was on October 10, 1979, with 0.3” at National Airport.

NOAA’s Climate Prediction Center expects October 2026 to feature near average temperatures and rainfall in the nation’s capital. That would be in contrast to last October that was both cooler and drier than average.