Category: Posts EN

Dual Tropical Threats for the Central Gulf Coast in the Upcoming Week!

Written by Team Morecast

 

Tropical Storm Marco is currently entering the southern Gulf of Mexico through the Yucatan Channel. Meanwhile, Tropical Storm Laura is pouring torrential rain across Puerto Rico with Hispaniola and Cuba next on the docket. Interactions with dry air and land masses could restrict how much intensification either system will achieve. However, there is very warm water ahead. The potential exists for not one but two hurricanes to impact the central Gulf Coast in the early to middle of the upcoming week.

 

 

There were major shifts in model guidance with regards to Marco today. Last night it appeared Marco would turn west towards coastal Texas. However, the consensus now is for a north-northwesterly track towards Louisiana. Landfall will occur on Monday, likely in the afternoon or evening. Marco has struggled to maintain persistent, strong storm activity around its core, a necessary prelude to intensification. However, favorably warm water and moderate shear lie ahead over the open Gulf of Mexico. Models suggest Marco will strengthen to minimal hurricane status before landfall and hurricane watches have already been issued.

 

 

Tropical Storm Laura is about to hit the Dominican Republic. Interaction with the rugged terrain of Hispaniola and then Cuba in the next few days should disrupt Laura’s circulation and prevent significant intensification. However, Laura will encounter the same favorable conditions over the open Gulf as Marco by early next week. Strengthening is likely and Laura may be a minimal hurricane as it approaches a coastal Louisiana landfall on Wednesday.

 


Dangerous high winds, storm surge, and flooding rainfall can be expected on Monday and early Tuesday, then again on Wednesday to early Thursday. The dangers posed by Laura would be compounded by infrastructure weakened by Marco’s hazards a few days earlier. Emergency services will be severely strained with not enough recovery time between the storms. Even if the storms are only Category One level, two hurricanes making landfall in the same area within 72 hours of each other would be unprecedented in the U.S. meteorological record. A shift of track for either storm would obviously bring some relief to the target zone, but also bring a wider area of the Gulf Coast into imminent danger. Lead photo courtesy flickr user Mary Madigan.

 

 

Blistering Heat and Drought Spark Roaring Wildfires in the Western U.S.

Written by Team Morecast

 

Extremely hot, dry conditions have combined with a rash of dry lightning storms to produce raging wildfires across large swaths of central and northern California. These fires have consumed hundreds of thousands of acres and many homes and businesses. Mandatory evacuations have emptied numerous communities.

 

 

Little to no rainfall has fallen in the past three months across the region (see map above). This in and of itself is not out of the ordinary, but the extreme heat is. Most of the Desert Southwest up into the Sacramento Valley is running 4-5 deg above climatological averages in July and August. In fact July 2020 was the hottest month on record in Phoenix, Arizona with an average temperature of 99 degrees F (37 deg C). That average includes both daytime and nighttime readings! In fact, lows stayed above 90 deg F (32 deg C) for more than half the month in Phoenix, another record. Not to be outdone, the Furnace Creek Visitor Center in Death Valley recorded a scorching 130 deg F (54.4 deg C) on Sunday afternoon. Once confirmed, it will be the hottest temperature there in more than a century, and the third-highest ever recorded on Earth!

 

 

What little precipitation has occurred has come in the form of isolated pop-up thunderstorms. They produce little in the way of rainfall but do contribute fire-sparking lightning activity. Some of the fire complexes have grown so large and hot they’ve created their own weather. These “pyrocumulonimbus” clouds behave like any other severe cell, tapping into upper atmospheric spin to produce hellish fire tornadoes on the ground (see tweet videos above). Unsurprisingly, air quality has been very poor across much of the region due to the smoke and ash. These conditions would be unhealthy enough on their own, but combined with the ongoing COVID pandemic, there is an extreme danger posed to the elderly and those with chronic respiratory conditions. Lead photo courtesy Mike Lewelling, National Park Service.

Hurricane-Like Derecho Spreads Destruction Across the Upper Midwest

Written by Team Morecast

 

A swath of destructive winds up to 110 mph (175 kph) accompanied a long-lived squall line known as a derecho through the Midwest. The 700+ mile (1,125+ km) path included the Chicago metro area on Monday afternoon. An embedded tornado within the squall caused enhanced damage on the city’s north side. More than a million residents in the region remained without power as late as Tuesday morning.

 

 

The derecho began as a cluster of severe storms along the South Dakota-Nebraska border early Monday morning. In the first few hours, giant hail was the main hazard with some stones up to softball-sized. By late morning the cluster had organized into a fast-moving bow echo raking central Iowa. This was probably where the highest winds and worst damage occurred. Midway, Iowa recorded a gust to 112 mph (180 kph), as strong as a Category Two hurricane. Residents reported these intense winds lasted up to 15-20 minutes. They compared the destruction to tornadoes that typically cover a smaller area and last a shorter amount of time. Officials estimate up to one-third of the state’s staple corn crop was destroyed, only weeks after the region had celebrated recovery from a drought. The damage was so widespread that it was visible on satellite imagery the next day (see bottom tweet).

 

 

 

 

The squall line crossed into northern Illinois early in the afternoon, slamming Chicago in the mid- to late afternoon. Gusts were measured up to 80 mph (130 kph) in the city, felling many trees and powerlines. The derecho slowly weakened in the evening, but continued to cause significant damage across northern Indiana and even northwest Ohio. By the end of its 14-hour lifespan, the derecho had produced more than 500 high wind reports across eight states and covered 770 miles (1,240 km). That’s an average speed of 55 mph (90 kph), but at its peak the squall moved as fast as 70 mph (110 kph)!

TUESDAY NIGHT UPDATE: Isaias Rakes the Eastern Seaboard with High Winds, Tornadoes!

Written by Team Morecast

 

Hurricane Isaias made landfall in southern North Carolina late on Monday evening. Less than 24 hours later, the storm is leaving the New England states. In between lies a path of damaging winds, flooding rains, and tornadoes. The densest population centers in the U.S. saw widespread winds of 60-80 mph (100-130 kph), felling countless trees and powerlines and leaving millions without power.

 

 

 

 

Isaias has left a unique mark on the history of tropical cyclones. The storm experienced a surge of intensification before landfall near Ocean Isle Beach, NC. That intensification helped produce a dangerous surge up to six feet (1.8 m) high for coastal NC, flooding homes and cars and leaving a thick layer of beach sand burying whole communities. Isaias interacted with a large trough in the Midwest that injected extra energy into the storm. The storm was thus able to retain strength over inland areas where most cyclones die. Destructive winds swept up the entire East coast with gusts of 70-80 mph (115-130 kph) reported as far north as the Big Apple. The highest winds lasted only a few hours with the storm sprinting north, but it was plenty enough to cause widespread damage. At least 25 tornadoes were also reported during the morning hours in the Mid-Atlantic, producing smaller pockets of extreme damage. Inland areas saw heavy rain up to ten inches (250 mm) leading to localized flooding. Lead photo courtesy flickr user woodleywonderworks.