Hurricane Gonzalo and Hurricane Fabian

Hurricane Fabian 2003  (Source: NOAA)

Although the past two seasons have featured below average activity in the tropics, all it takes is one storm to cause catastrophic effects. Such is the case with Hurricane Gonzalo. Gonzalo, the strongest Atlantic hurricane since Ophelia in 2011, is expected to arrive in Bermuda this evening.  Since Bermuda is farther North, it doesn’t usually experience direct impacts from tropical systems but sometimes experiences fringe effects from storms as they head Northward and out to sea. That’s what makes the threat from a major hurricane like Gonzalo especially significant.

A Category 4 storm, Gonzalo may weaken to a Category 3 before effecting Bermuda tonight. Even at Category 3 intensity, Gonzalo will be the strongest storm to hit Bermuda since Fabian in 2003. Fabian caused major damage on the island and the fear is Gonzalo will cause similar damage.

Tropical storms and hurricanes are also rare in Hawaii.  Just below hurricane strength, Tropical Storm Ana is nearing the Hawaiian Islands and will bring gusty winds and heavy rain through tomorrow.  Ana may reach minimal hurricane intensity (with sustained winds of at least 74 mph) but the effects on the Hawaiian Islands would be the same with heavy rains and gusty winds. 

 

Ana is actually the second tropical system to affect Hawaii this season after Iselle caused major damage in August.  So the combination of a major hurricane (Gonzalo) having a direct impact on Bermuda combined with two tropical systems effecting Hawaii in the same season is an exceptionally rare occurrence.

1992 was also a quiet hurricane season but featured one catastrophic storm, Andrew.  Even during a below average hurricane season, it only takes one storm to make it a damaging and deadly season.

Hurricane Hazel - 60 years later

Hurricane Hazel's track (Source: NOAA)

On this date in 1954, the Mid-Atlantic Region experienced one of its worst hurricanes on record.  The strongest and most destructive hurricane of the season, Hurricane Hazel made landfall near the border of North Carolina and South Carolina as a major Category 4 hurricane.  Hazel remained stronger farther inland and failed to weaken due to its rapid movement northward.

Consequently, Hazel brought major damage as far north as Eastern Canada.  The Nation’s Capital observed its strongest wind gust on record of 98 mph at National Airport.  By comparison, the Nations Capital’s highest wind gust during the June 2012 derecho was 70 mph. Hazel’s 98 mph wind gust equates to sustained winds seen during a Category 2 hurricane.  The name Hazel was retired from future use.

October typically sees tropical storm formation in the tropics.  Other major hurricanes to occur during the month of October included Hurricane Iris in 2001, which was a Category 4 storm and caused major damage in Central America.  In October 1988, Hurricane Joan was also a Category 4 hurricane that caused major damage in the Caribbean and Central America.  Hurricane Joan was a rare storm in that it crossed Central America into the Eastern Pacific.  Once this happened, since Joan was no longer in the Atlantic Ocean, “Joan” was given a new name from the Eastern Pacific hurricane list and became Tropical Storm Miriam.  Like Hazel, the names Iris and Joan were also retired.

Just this week Hurricane Gonzalo developed not far from where Hazel formed 60 years ago and is currently a Category 4 storm.  Gonzalo is expected to change course and head northeast towards Bermuda, sparing the East Coast a direct impact.  Gonzalo is the strongest hurricane to form in the Atlantic since 2011. 

Weather Quiz

Hurricane Vince on October 9, 2005

True or False:

On October 11 2005, the Iberian Peninsula observed its first known tropical cyclone.

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Answer to question from October 5:

C.  Opal

Hurricane Opal made landfall along the U.S. Gulf Coast on October 4, 1995 where it caused significant damage.  It then quickly tracked northeast and brought significant weather to the Mid-Atlantic Region including significant rainfall and several tornadoes.  The name “Opal” was subsequently retired from future use meaning there will never be another storm named “Opal.”  Hurricane Gloria occurred in 1985 while Hurricanes Bertha and Fran came in 1996.

Major October Hurricanes

Hurricane Mitch at peak intensity (10/26/1998)

Although September is the peak of the Atlantic hurricane season, October has seen a number of major hurricanes. Some of the more notorious include Hurricanes Hazel, Mitch and Wilma. October hurricanes tend to concentrate in the Western Caribbean Sea and Gulf of Mexico where the water remains warmer and the winds remain favorable longer in the hurricane season.

Hurricane Hazel was a deadly storm that caused catastrophic damage in the Caribbean before it turned toward the East Coast.  On October 15, 1954, Hazel made landfall as a Category 4 hurricane near the North and South Carolina border.  Moving quickly northward, Hazel’s damaging effects were felt as far north as Eastern Canada.  Washington, D.C. saw its highest wind gust on record of 98 mph observed at National Airport.

Back on October 26, 1998, Hurricane Mitch became the Atlantic Ocean’s first Category 5 hurricane since Andrew in 1992; with sustained winds up to 180 mph. Conditions were ideal with exceptionally warm ocean water, well above the 80 degree Fahrenheit threshold for hurricane development. Since the prevailing wind pattern was weak and didn’t steer the storm away, Hurricane Mitch was left to slowly meander around the Southwest Caribbean Sea. That led to severe flooding in Central America that unfortunately caused widespread devastation and a tragic loss of over 11,000 lives.

During the record setting 2005 season, the strongest hurricane ever recorded in the Atlantic Ocean formed in almost the same spot as Hurricane Mitch. Once again, atmospheric conditions were ideal for rapid intensification of the hurricane with extremely warm ocean water. Hurricane Wilma became a Category 5 hurricane on October 19, 2005 with sustained winds of 185 mph. Winds gusted over 200 mph around the center of both Mitch and Wilma. Wilma’s lowest observed air pressure was 882 millibars. By comparison, Hurricane Mitch’s lowest air pressure was 905 millibars. The lower the air pressure, the stronger the storm is.

On the Saffir-Simpson hurricane intensity scale, a Category 1 hurricane has sustained winds of 74 mph – 95 mph around the center of the storm, while a Category 5 storm has sustained winds of at least 156 mph. Hurricanes become “major”once they reach Category 3 status with sustained winds around the center of the storm of 111 mph.  Due to their damaging and deadly legacies, the names Hazel, Mitch and Wilma have all been retired by the World Meteorological Organization and will never be used again on future storms.

Weather Quiz

The weather in the Mid-Atlantic Region is impacted by tropical systems every few years.  Hurricanes, such as Floyd, Isabel, Irene and Sandy, should all be familiar to Mid-Atlantic residents of the last 15 years.  The 1995 hurricane season was a particularly active one with 19 named storms.  What was the name of the former hurricane whose remnants had a significant impact on the Nation’s Capital on this date in 1995?

A.  Fran

B.  Bertha

C.  Opal

D.  Gloria

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Answer to question from September 26:

Local ocean currents help regulate ocean temperature around the world.  On the East Coast of the United States, the Gulf Stream is a warm ocean current that brings water northward from the tropical Atlantic. This is why hurricanes can remain strong as the track northward outside of the tropics.  On the west coast, the California current moves southward from British Columbia to the southern tip of Baja California.  This southward moving current brings cooler ocean water southward and is why the water off the west coast of the United States is cooler than along coastal areas of similar latitudes on the East Coast.

October Almanac

Estimated times for peak fall foliage

October is often a transitional month that starts warm but often ends with our first frosts in the Mid-Atlantic Region. The average high and low temperatures in the Nation’s Capital on October 1 are 74 and 56. By Halloween, the average high and low temperatures fall to 64 and 46 according to the National Weather Service. October averages 3.40” of rain in Washington, D.C.

Guess what ? The Nation’s Capital has seen measurable snowfall in October! Our earliest measurable snowfall came on October 10, 1979, when 0.3” fell at National Airport. Although a small amount, it proved to foreshadow that winter season which ended up with above average snowfall.

The earliest freezing temperature reading downtown was on October 10, 1895. Our latest 90 degree day was on October 11, 1919. In 2005, Washingtonians experienced the wettest October on record when 9.41 inches of rain fell. That followed the driest September on record at National Airport; Washington, D.C.’s official weather reporting station.

October can also see appreciable rainfall from the remnants of former tropical systems. Such was the case with the remnants of Hurricane Opal in 1995 that brought three weak tornadoes to Maryland during the first week of the month.  Sandy brought widespread damage and record rainfall to the Mid-Atlantic Region in late October 2012.

This month has gotten off to a mild start with high temperatures in the 70s.  However, that will change this weekend after a cold front ushers in cooler, more fall-like weather with highs in the 60s Saturday and Sunday.

Autumn Typically Features a Variety of Weather

Late September is when Washingtonians can usually start feeling the change in seasons in earnest.  The month of September begins with an average high of 84 degrees in the Nation’s Capital but that falls to 74 degrees by the end of the month.  However, it isn’t always a seamless transition to autumn and the change in seasons typically yields a multitude of weather.

Such was the case on September 27, 1993.  The day featured high temperatures in the upper 70s but those living in the area at the time will remember what happened in the early afternoon.  That’s when a line of severe thunderstorms brought several tornadoes from Loudoun County, VA to north central Maryland.  Although the spring is when the United States sees the highest frequency of severe thunderstorms, the autumn also sees severe weather as the seasons change.

September 1998 was a warmer than average month in the Nation’s Capital with temperatures reaching at least 90 degrees on ten different occasions.  The final 90 degree day of the month came 16 years ago today when a record high of 95 degrees was set at National Airport (the official weather reporting site for Washington, D.C.).  September 2010 was also a warm month with ten days of 90 degree heat as well.  By comparison September 2011 saw no 90 degree heat.

Fortunately, there is no extreme weather in the seven day forecast.  In fact, tomorrow's weather will feature weather similar to today being mostly sunny and stellar with highs in the low to mid 80s.