Unusual summer nor’easter brings heavy rain, gales and rough seas to the coastal Atlantic

An abnormally strong low pressure system impacted the Mid-Atlantic States over the weekend. During the time of year when attention usually turns to the tropics, a winter-like Nor’easter lashed areas from D.C. to Atlantic City. The storm was spawned by a broad 500mb Analysis valid 12z 29 July 2017deep-layer trough diving into the northeastern United States from Ontario. An extended area of surface low pressure formed on Friday morning. This low stretched from Boston southwestward through West Virginia before becoming organized over Virginia during the afternoon hours. Above average sea-surface temperatures allowed ample moisture to push across the Delmarva Peninsula toward the nation’s capital. Widespread heavy rain showers developed Friday afternoon and evening, and flash flood warnings were issued from D.C. to Baltimore. Before the storm wound down on Saturday, over four inches of rain had fallen across Maryland’s most populous city, with areas to the east seeing almost six inches of rainfall.

Conditions were no better offshore, where Gale Warnings were issued from Morehead City, North Carolina to Cape Cod, Massachusetts. As the system was developing, model guidance indicated the potential for wind gusts near 70mph offshore, which is near hurricane force. Fortunately, these extreme winds did not materialize, but widespread sustained winds in excess of 35mph were noted from the Chesapeake Bay northeastward toward Rhode Island. This allowed seas to become quite rough, with significant heights pushing 12 feet just off the coast of Delaware Saturday evening.

The unseasonable strong storm finally subsided on Sunday while quickly moving east of the region. Although not tropical in nature, this weekend’s system was a reminder that the East Coast is entering the time of year where weather becomes the forefront of the mind, and this could be even more the case this August, as it looks to be particularly active in the tropics. Stay tuned!

Tornado Diaries: May 18th, 2013

The first post in this series detailed an exhilarating and dangerous chase under cover of night in northwestern Iowa. As a storm chaser, the drawback to a night chase is the near impossibility of acquiring photos and videos of the storms. On the afternoon of May 18th, 2013, darkness was not an issue as a violent tornado tracked across the open country of southwestern Kansas.

I had just graduated from Iowa State University the week before. My thoughts at the time were not on severe weather, but that would quickly change as long range forecast models indicated a multiple day severe weather threat across the Southern Plains. Recent grads and I made the decision to embark on one last chase in Oklahoma and Kansas before moving into the “real world.”

Read More »

Tornado Diaries: April 9th, 2011

Most meteorologists recall a moment in their childhood that fostered their obsession with weather. My moment was in second grade, when a severe thunderstorm hit my hometown while school was in session. I vividly remember classmates being frightened, while I sat in the school’s basement thinking the situation was pretty sweet, to use with the parlance of a second grader. After that day, I was hooked on severe weather, and although that specific event did not spawn a tornado, I remain fascinated by them to this day.

Many years later while attending Iowa State University in Ames, Iowa, I had opportunities to travel across the Midwest during spring and summer, in search of the elusive and dangerous tornado. There are three specific storm chases I will be detailing this spring, the first of which occurred on April 9th, 2011.Read More »

Severe Storms Roll into the New Year

NCDC Level-II Data January 2017
NEXRAD Level-II reflectivity (left) and velocity (right) from 8:30am CST 01/02/17

It was a stormy and soggy start to 2017 for millions along the Gulf coast as a vigorous line of thunderstorms tracked from Southeast Texas to the Florida Panhandle on January 2nd. Sparked by an amplified trough of low pressure aloft, surface low pressure moved across Southeast Texas early Monday, causing widespread convection to form along and east of I-35. These storms moved quickly eastward through the morning hours, entering the Houston metro area after 7am CST.

Read More »

2015 Holiday Storm Retrospective

A powerful storm system tracked across the northern Great Plains this holiday season. Heavy snows and blizzard conditions were observed in the Dakotas, strong storms occurred in Kansas and Missouri, and an ice storm developed in areas between. Of significant note was a tornado report in Kansas that if confirmed would be the first tornado recorded on Christmas day in that state. In addition, wind gusts in excess of 70 mph were reportedIowa Environmental Mesonet Wind Speed Reports December 2016 in northwestern Iowa, causing structural damage in the area. These conditions are a stark reminder that like meteorologists, Mother Nature does not take the holidays off. Interestingly, a similar storm system impacted the southern plains last holiday season.

One year ago, a major storm system moved from Texas through the Great Lakes, capping off a year filled with extreme weather in Texas and beyond. Read More »

Major Hurricane Wilma, 11 years later

CIMSS NOAA Satellite Montage WilmaHurricane Wilma was the 21st named storm of the infamous 2005 Atlantic hurricane season. From her formation on October 15th to her demise on the 26th, Wilma would become one of the most memorable hurricanes in Atlantic basin history. As the 4th category 5 hurricane of the year, Wilma would become a monstrous bookend to an incredible, record-setting season.Read More »

Remembering 2005’s Major Hurricane Rita in the Gulf of Mexico

Hurricane Rita made landfall in extreme southwestern Louisiana on September 24th, 2005 with an intensity of 100 knots (Category 3). About 48 hours earlier, Rita was a Category 5 hurricane with a minimum pressure of 895mb, the fourth-lowest central pressure on record in the Atlantic basin. Although Rita’s history was overshadowed by Katrina, which made landfall just a few weeks earlier, the storm provided a unique challenge for both forecasters and public officials.

NASA Rita Terra satellite_20050918
NASA satellite image of Tropical Depression Eighteen over the Bahamas on Sept. 18, 2005

Rita originated as a weak tropical wave off the western coast of Africa on September 7th. The Saharan Air Layer, commonly known as Saharan Dust, and high levels of wind shear prevented the wave from producing thunderstorm activity as it moved across the tropical Atlantic. Conditions became more favorable for development later in the month as the wave reached the Bahamas. A tropical depression formed on September 17th and the system was designated as Tropical Storm Rita the following afternoon.

Rita continued to strengthen as it tracked across the Florida Straits, reaching Category 2 status by the time it reached the Gulf of Mexico on the 20th. Over the next 18 hours, the storm underwent rapid intensification over the Loop Current, becoming a Category 5 storm with an intensity of 145 knots. Rita continued to intensify and recorded an incredible 70mb drop in central pressure in a 24-hour period. At maximum intensity on September 22nd, Rita’s central pressure was estimated to be 895mb with winds near 155 knots (178 mph).

NASA Aqua satellite_20050923
NASA satellite image showing Hurricane Rita approaching the Gulf coast on Sept. 23, 2005

Thankfully for the residents of the Gulf Coast, Rita did not maintain its unprecedented strength as it pushed ashore. After moving past the Loop Current the system gradually weakened to a Category 3 before making landfall near Sabine Pass as a major hurricane. Hurricane force winds spread over 150 miles from the center while tropical storm force winds stretched as far north as the Louisiana/Arkansas border. Peak storm surge of nearly 17 feet occurred on the eastern side of Rita, causing severe flooding in several parishes in southwestern Louisiana. Heavy rainfall worsened this situation, with most of southwestern Louisiana receiving 7-10 inches, with some areas receiving over 15.

Rita continued to progress northeastward after being absorbed by a front across the central United States. That accelerated movement prevented a significant flood event in the Ohio River valley, with most rainfall totals being limited to around 2-3 inches as the remnant low raced toward the Great Lakes.

Although meteorological impacts to extreme southeastern Texas and southwestern Louisiana were unforgettable, only seven direct deaths occurred as a result of Rita in the United States. Most citizens in the southwestern Louisiana coastal areas evacuated before the worst impacts arrived, likely significantly reducing the death toll in that area.

The majority of the storm’s causalities occurred during the evacuation iWWT Hurricane Rita Wind Speed Analysisn Texas, where poor planning and heightened fears, resulting from Katrina, resulted in mass gridlock around Houston. Over 100 Texans perished due to accidents, fires, and health related issues during the evacuation. Much work has since been done to streamline the evacuation process from the Houston area, including the streamlining of the contraflow process on major highways exiting the city.