US Gulf Coast put on alert for potential tropical storm to form late week

After more than a month of inactivity in the tropical Atlantic basin, development is likely in the northern Gulf of Mexico with potential impacts to residents and visitors later this week and this weekend.

A non-tropical system tracking through and triggering showers and thunderstorms across the South early this week will eventually end up over the warm waters of the Gulf of Mexico around midweek.

"The storm will then sit over the Gulf of Mexico for a few days and may eventually become partially or fully tropical in nature during the time period from late this week into next weekend," according to AccuWeather Senior Meteorologist Adam Douty.

Dry air, dust and strong wind shear has prevented tropical development across the Atlantic basin since Subtropical Storm Andrea briefly roamed the waters of the west-central Atlantic in late May.

However, more conducive conditions exist over the eastern Gulf of Mexico.

With strong wind shear absent, warmer-than-normal waters of the eastern Gulf of Mexico can allow an organized tropical or subtropical system to take shape.

The next tropical storm in the Atlantic basin would be called Barry.

A subtropical storm has both tropical and non-tropical characteristics, but can have must as much impact in terms of heavy rain, rough seas and strong winds.

"One of the keys to whether a depression or storm will form is how close the system tracks to the coast," Douty added. "The longer the system remains over water, the stronger it may become," he said. "However, it may stay non-tropical if it stays near land."

Development of the feature will be slow initially. However, once it catches, and if the feature remains offshore, it could gain strength at a fast pace.

"Since there is a chance for the feature to move over open water, it is premature to say that the only threat will be from torrential rain," according to AccuWeather Senior Meteorologist Alex Sosnowski.

The latest trends in steering winds suggest more of drift toward the central and western Gulf of Mexico this weekend.

"There are a number of petroleum rigs and refineries along the central and western Gulf coast, and there may be considerable risk if this storm ramps up, develops to its full potential and travels in that direction," Sosnowski said.

Seas would turn dangerously rough for boaters and swimmers as the storm strengthens.

Regardless of development, the system may lead to multiple days of showers and thunderstorms that can spoil vacation and outdoor plans across the Southeast this week.

Flood dangers can arise in areas that get hit repeatedly by downpours or where a more concentrated band of heavy rain unfolds.

"As we have seen in the past couple of decades in the Deep South, sometimes these tropical features stall and produce torrential rainfall once they make landfall," according to AccuWeather Hurricane Expert Dan Kottlowski.

"Allison did that in 2001 and Harvey did that in 2017," Kottlowski said.

While Harvey was once a major hurricane, Allison peaked as a tropical storm. So a powerful hurricane is not necessary for tremendous rainfall and flooding.

A broad area of moisture alone will cause downpours and localized flooding over parts of the Southeast, including the Florida Peninsula this week even in absence of any tropical depression or storm.

"Residents from western Florida to eastern Louisiana should especially remain alert for an increase in downpours and a heightened risk for flooding later this week and into the start of the weekend," Douty said.

The downpours would spread westward, depending on the storm's eventual development and track. 

After the system leaves the Gulf of Mexico, its eventual track will determine whether heavy rain aims for the interior South or the threat continues in the Deep South.

With weak steering winds now and into next week, any feature that wanders onshore may not be in a hurry to leave or move well inland.

Kottlowski has been warning since early April that the Gulf of Mexico, as well as areas east of Bermuda and off the southeastern coast of the U.S. need to be watched closely for early season development due to water temperatures running above normal.

AccuWeather’s 2019 predictions have not changed since the initial forecast was released on April 3.

Forecasters continue to call for 12 to 14 tropical cyclones this season. Of those, five to seven are predicted to become hurricanes and two to four are predicted to become major hurricanes.

While El Niño conditions may suppress the numbers of tropical storms and hurricanes in the Atlantic basin somewhat this year, all it takes is for one or two hurricanes to strike populated areas and result in great risk to lives and property.

This year, AccuWeather will implement its RealImpact™ Scale for Hurricanes to assist with public safety and understanding, as well as risk of damage should a tropical threat arise.

"If the scale was retroactively used, Tropical Storm Allison would have a RealImpact of 4 and Harvey would have a RealImpact of 5, based primarily on flooding rainfall," Kottlowski said.

Tropical Storm Emily from 2017 was the last time that a named tropical system made landfall in the United States during the month of July. Emily formed in the eastern Gulf of Mexico and moved into the central Florida Peninsula on the last day of July.

Tropical development more likely in the Gulf of Mexico

There are currently no organized tropical systems across the Atlantic Ocean, though AccuWeather meteorologists are monitoring for development across the Gulf of Mexico during the second half of the week.

A weak upper-level disturbance will drop to the south into the northeastern Gulf of Mexico later on Tuesday and into Wednesday and will slowly drift to the west through the remainder of the week. The water across the Gulf is very warm and wind shear is expected to be conducive for tropical cyclone formation. As a result, it is increasingly likely that a tropical system will form in the northern Gulf later this week.

Accuweather meteorologists will be closely monitoring this potential over the next several days. Given uncertainty in the track, anyone with interests from eastern Texas to northern Florida should monitor the progress of this system.

Elsewhere across the basin, either high wind shear or large amounts of dry, dusty air will continue to inhibit tropical development from the Caribbean into the eastern Atlantic.

By AccuWeather Senior Meteorologist Adam Douty.

Could a tropical storm brew before the middle of July in Gulf of Mexico?

Showers and thunderstorms forecast to congeal along the coast of the southern United States next week and could slowly allow a storm to brew that may be tropical in nature.

While much of the Atlantic Basin is likely to remain hostile for tropical development due to large areas of dry air, dust and wind shear, there is a somewhat more likely area where development may take place in the coming days.

The southeastern part of the nation, including parts of the Gulf of Mexico and the western Atlantic, will become an active zone for showers and thunderstorms into next week

Slightly cooler air aloft associated with a developing non-tropical storm, combined with warm and humid conditions, will spur on thundery downpours this weekend through next week.

However, during next week through next weekend, the storm aloft may slowly spin down to the surface.

"At this time, it appears the most likely area for slow development would be over the northeastern Gulf of Mexico, perhaps near the coasts of Florida, Alabama, Mississippi and southeastern Louisiana," according to AccuWeather Hurricane Expert Dan Kottlowski.

"That development could be tropical or subtropical in nature," Kottlowski said.

A subtropical storm has both tropical and non-tropical characteristics.

Subtropical storms tend to be somewhat lopsided and may contain pockets of dry air near the center. However, in terms of impact, they can also bring heavy rainfall, rough sea and surf conditions and strong winds, just like their true tropical storm cousin.

Development may occur as early as the middle of next week or as late as next weekend. It is also possible that the system fails to develop should all the necessary ingredients not come together.

It is possible that the development zone extends northeastward off the Georgia and Carolina coast next week. This will be a swath where showers and thunderstorms extend over the Atlantic.

In any event, the area around the northeastern Gulf coast may be prone to several days of downpours from a slow-moving storm.

At some point, the more concentrated batch of downpours and thunderstorms associated with the feature, tropical or not, may be pulled inland over the South and then northeastward around an area of high pressure near Bermuda.

There is another area, located in a narrow zone immediately west of Africa, where there is a plume of moisture and slightly lower wind shear.

This area is the source of tropical waves or disturbances that move westward across Africa in the form of gusty winds and locally heavy thunderstorms.

These waves often result in the bulk of tropical storms and hurricane over the Atlantic Basin from August through September and October. This period is the heart of hurricane season with the peak in September.

Any such development through next week off Africa will have to fight against dry, dusty air to the immediate north.

While El Niño conditions may suppress the numbers of tropical storms and hurricane in the Atlantic basin somewhat this year, all it takes is for one or two hurricanes to strike populated areas and result in great risk to lives and property.

This year, AccuWeather will implement its RealImpact™ Scale for Hurricanes to assist with public safety and understanding, as well as risk of damage should a tropical threat arise.

The Atlantic basin remains quiet for now

There are no organized tropical systems across the Atlantic Ocean, and AccuWeather meteorologists do not foresee tropical development through the weekend.

Much of the basin is being dominated by either high wind shear or large amounts of dry, dusty air. While there are several tropical waves traversing the Atlantic Ocean, the aforementioned factors will continue to inhibit any development through the end of the week.

There are projections showing a few stronger tropical waves emerging from the coast of Africa, one this weekend and a second early next week. These waves may have a higher chance of development than tropical waves we have seen during the past few weeks, but current modeling does not show significant strengthening with these. Wind shear is projected to lessen across the eastern Atlantic during this time, so the main limiting factor may be the dry and dusty air coming from the Sahara.

Later next week, an upper-level low pressure system over the southeastern United States may emerge over the eastern Gulf of Mexico for a couple of days. If this occurs, very warm water and relatively low wind shear in that region may allow a tropical or subtropical system to develop near the Eastern Gulf Coast. Accuweather meteorologists will be closely monitoring this potential over the next several days.

By AccuWeather Meteorologist Max Vido

Typical Summer Hailstorm Causes Climate Change Hysteria

By Chris Martz | July 1, 2019

Follow @ChrisMartzWX

Did you hear about the hailstorm that just recently hit Guadalajara, Mexico (Figure 1)? 

Figure 1. Hail cleanup in Mexico.

You likely did and while impressive in photos, it was nothing out of the ordinary for the region. It's once again, wacky journalism and scientific illiteracy that has you all hyped up and in panic mode. Numerous articles have surfaced, like this one from CBS News describing how "6 feet of hail fell on Guadalajara, Mexico" (Figure 2).¹ Please note that I have nothing against CBS News, I'm just pointing out the simple fact that the article is a bit misleading...

Figure 2. Freak hailstorm dumps up to 6 feet of ice on Guadalajara, Mexico - CBS News.

Social media (i.e. Twitter) started to jump on the bandwagon train after articles like this were published, and it didn't take long before people began to blame global warming, climate change, the ecological breakdown, climate crisis, global heating, global change, or whatever they call it nowadays on the "freak" hailstorm. 

The governor of the Mexican state Jalisco, Enrique Alfaro, suggested that climate change may be the cause of the hailstorm.¹ The entire problem with that mindset is that climate change — regardless of the main cause — does not actually cause [extreme] weather events. Climate change itself may amplify or reduce extreme weather intensity or frequency to a degree, but it most certainly does not cause extreme weather to occur. It is unknown whether or not a certain weather event would occur in a warmer or colder world, considering that events like hailstorms have occurred for as long as we know.

What Causes Hail?

Hail itself is a common occurrence during summertime, as they form from frozen water droplets that collide with supercooled water droplet suspended in the air by thunderstorm updrafts.² ³ ⁴ The stronger an updraft is, the longer the hailstone stays in the air colliding with more supercooled water droplets, and as a result, the larger the hailstone grows.² ³ ⁴ Eventually, it along with other hailstones become too heavy, and fall to Earth's surface from the thunderstorm updraft.² ³ ⁴ (See Figure 3).

Figure 3. Hail formation - original image from Brad Panovich.

Hailstorms in NW Mexico Are More Common Than You Think

Like hail, lightning is a good indicator of thunderstorms. The map below (Figure 4) shows the average annual number of lightning strikes per square kilometer across the globe.² As you can see, western, mountainous Mexico — where Guadalajara is located — sees a high number of lightning strikes per year, as compared to other areas.² This is a good indicator of frequent hailstorms.

Figure 4. Lightning flashes per year.

A 1977 study of North American Hail by Stan Changnon Jr. found that hail is most likely to occur during the Spring and Summer months in the Central Plateau and high mountains of Mexico, while simultaneously less common around coastal mexico and the Yucatan Peninsula.² ⁵ Moreover, mountainous regions experience on average, four or more "hail days" annually.² ⁵

While average annual lightning strikes — as previously stated — are a potential indicator of more hailstorms as Dr. Marshall Shepherd noted, it's certainly not applicable to all locations. For instance, Florida has the most annual number of thunderstorms in the U.S., but at the same time less hail than Colorado, Nebraska, and Wyoming — commonly referred to as "hail alley."² Those three states on average have seven to nine hail days per year according to NOAA.² The reason for this is because the freezing level in the atmosphere — where temperatures fall to freezing — is closer to the ground due to mountainous terrain as compared to Florida's flat terrain.² The same can be said about Guadalajara, which sits at an elevation of 5,138 feet.² ⁶ This high elevation, once again means that the atmosphere's freezing level is closer to the ground, thus it should be to no surprise that hailstorms are a somewhat common occurrence.

Meteorologist Dr. Roy Spencer, of University of Alabama Huntsville (UAH), found this hand-drawn map (Figure 5) of global hail frequency from a 1973 study.⁷ The map clearly shows that Guadalajara receives a great number of hail days per year.⁷ Somehow, journalists completely omitted this.

Figure 5. Global hail frequency.

What About That "6 Feet of Hail?"

This simply didn't happen. Six feet of hail did not fall out of the sky onto Guadalajara. When major hailstorms occur, heavy rain is often present, and as we know, heavy rain causes flooding.⁷ This flooding causes currents of water to flow through streets, in which hail becomes deposited into large, scattered piles.⁷ 

The Summary of It All

It should be eye-opening to you that people actually think every weather event is this existential crisis. It should also be eye-opening to you that people think every weather event that occurs has "never happened before." Perhaps it's just me, but I have seen a frightening rise in this mindset among people, that's politically motivated. 

As I have been saying for quite some time now, it's very important that people take a step back and look at the mechanisms and causes, rather than assuming it's climate change at work. This narrow view of catastrophic climate change continues to advance down a very dark path that needs to have it's brakes applied on immediately.

REFERENCES

[1] Brito, Christopher. "Freak hailstorm dumps up to 6 feet of ice on Guadalajara, Mexico." CBS News. July 1, 2019. Accessed July 1, 2019. https://www.cbsnews.com/news/mexico-hail-storm-up-to-6-feet-of-ice-dropped-guadalajara-north-mexico-city-in-summertime-freak-hail-storm-sunday/.

[2] Shepherd, Marshall. "Why Caution is Needed With Those Hail Pictures in Mexico." Forbes. July 1, 2019. Accessed July 1, 2019. https://www.forbes.com/sites/marshallshepherd/2019/07/01/why-caution-is-needed-with-those-hail-pictures-in-mexico/#759936502cf5.

[3] "How Does Hail Form?" NASA Precipitation Education. Accessed July 1, 2019. https://pmm.nasa.gov/education/content/how-does-hail-form.

[4] "Thunderstorm Hazards - Hail" NWS JetStream. Accessed July 1, 2019. https://www.weather.gov/jetstream/hail.

[5] Changnon, Stanley. "The Scales of Hail." Journals of Applied Meteorology. April 22, 1977. Accessed July 1, 2019. https://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281977%29016%3C0626%3ATSOH%3E2.0.CO%3B2.

[6] "Guadalajara." Wikipedia. June 23, 2019. Accessed July 1, 2019. https://en.wikipedia.org/wiki/Guadalajara.

[7] Spencer, Roy. "The 'Freak' Guadalajara Hailstorm wasn't So Freakish." July 1, 2019. Accessed July 1, 2019. http://www.drroyspencer.com/2019/07/the-freak-guadalajara-hailstorm-wasnt-so-freakish/.