Tropical Storm may develop in the Gulf of Mexico next week

The National Hurricane Center is monitoring the southwestern Gulf of Mexico for tropical development over the next several days. A low pressure is forecast to develop, which may acquire tropical characteristics, developing into a Tropical Depression or Tropical Storm. The National Hurricane Center gives this system a 40% chance to develop into a Tropical Depression or Storm over the next 5 days.

An area of showers and thunderstorms is forecast to develop over the weekend into early next week in the southwestern Gulf of Mexico. This area of thunderstorms will start to observe a lowering of pressure as the system starts to strengthen over the coming days. 

As the system continues to organize, it may develop into a well-defined low pressure by the middle of next week in the northwestern Gulf of Mexico. At this point, the low pressure may acquire tropical characteristics, developing into a Tropical Depression or Tropical Storm. 

The low, possibly tropical, by the end of the week will approach the Gulf States from late week into the weekend. There are too many questions to pinpoint where this system may move inland so all areas from Texas to Florida should keep a close eye on the forecast over the coming days. 

This forecast is fluid with quite a bit of uncertainty. A tropical system may not even develop, but regardless of development, tropical moisture and associated rain may move into the Gulf States by next weekend. Recent heavy rains across Texas, Louisiana, and Mississippi could lead to an increased flash flood concern if rain associated with this system impacts the region. 

Tropical system developing in the Gulf of Mexico

Monitoring an area of disturbed weather over the western Gulf of Mexico for possible tropical development Friday. This area of disturbed weather has gradually experienced a drop in pressure with increasing shower and thunderstorm coverage throughout Thursday into Friday. With the slow organization of this area of low pressure, recent model guidance continues to indicate the possibility of this developing into a low-end tropical system late-Friday.

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The environmental conditions do favor the possibility of tropical development. Atmospheric wind shear is minimal over the western Gulf of Mexico along with warm water temperatures. The Gulf of Mexico water temperatures have continued to warm through May and are now in the upper-70s & lower-80s. This would support tropical development. 

The National Hurricane Center is monitoring this area of low pressure over the western Gulf of Mexico and has increased the chance for tropical development to 40% Friday. 

A building upper-level high over the Southeast will help steer this low pressure north Friday, spreading deep moisture and heavy rain into southeastern and coastal Texas as well as coastal Louisiana. These areas have already received excessive rainfall amounts over the past week so heavy rain will increase the flood threat. The intensifying low pressure would act to increase the tornado potential along the upper-Texas coast late-Friday.  

Regardless of tropical development, the low pressure will spread heavy rain into southeastern and coastal Texas and coastal Louisiana Friday. If the low pressure gains tropical characteristics, it would likely remain weak–becoming a Tropical Depression or weak Tropical Storm, making landfall late-Friday along the upper-Texas coast. The 2021 Atlantic Hurricane Season begins June 1st. 

Subtropical system may develop in Atlantic

A broad area of low pressure northeast of Bermuda, in the North Atlantic, has a chance to develop into a subtropical system as it moves west-southwest over the next few days. The area of low pressure will begin to strengthen as it moves into a favorable environment with less wind shear and warmer ocean temperatures.

This environment may allow for a brief window of intensification into a subtropical system, possibly becoming the first subtropical storm of the season. The National Hurricane Center gives this broad area of low pressure a 90% chance for development into a subtropical system over the next five days.

If this system develops, it would become Ana. ‘Ana’ is expected to eventually turn north, moving into cooler waters and an atmosphere with high wind shear. This will quickly weaken ‘Ana’ and keep the system from impacting the U.S. Keep in mind, the 2021 Atlantic Hurricane Season begins June 1st.

Gulf of Mexico and Atlantic Tropical Outlook for the upcoming week

May 15th marks the first day of the National Hurricane Center (NHC) issuing routine tropical outlooks for the Gulf of Mexico, North Atlantic, and Caribbean Sea. The NHC is not expecting tropical cyclone formation during the next five days.

While the NHC is not forecasting any development of tropical cyclones over the next five days, numerical guidance has hinted at the possibility of tropical or subtropical development in the northern Gulf of Mexico in about seven days. The chances of this are low, but it is something to keep an eye on for the Gulf States. If a system were to develop, it would likely be unorganized and weak. However, May system can be efficient rain producers. This will be monitored over the coming days so keep checking back for updates.

Keep a close eye on the Gulf as May is growing increasingly tropically active

The Gulf of Mexico water temperatures continue to slowly increase as we move closer to Summer. Temperatures have risen into the 70s and 80s, which is a touch above average for the majority of the Gulf. The one exception is just off the coast of Mississippi, Alabama, and the Florida Panhandle where water temperatures are running a tad below average.

Overall, however, temperatures have recovered quite a bit from the February Arctic outbreak. The cold outbreak led to water temperatures significantly below average across the northwestern Gulf of Mexico to start Spring. This undoubtedly had a drastic impact on severe weather across the Plains. The water temperatures, as aforementioned however, have finally recovered.

This is a growing concern because we are just days away from the start of the Atlantic Hurricane season, which starts June 1st. Cold fronts that move south, will have the capability to stall over the norther and central Gulf of Mexico over the next couple of weeks, leading to the development of tropical cyclones.

Despite the official June start date, May cannot be slept on. In 2020, there were two preseason storms. Arthur developed in the middle of May while Bertha developed during the end of May. Over the past decade (2011-2020), ten preseason storms have developed, which is the most in modern record-keeping.

The 2021 Atlantic Hurricane Season is forecast to be above average. This coming off the most active hurricane season on record with 30-named storms and 6 hurricanes hitting the United States. One of the most well-known and prestigious outlooks was released several weeks ago. Colorado State University announced its 2021 Atlantic basin seasonal hurricane forecast and is expecting an above average season with 17 named storms, 8 hurricanes and 4 major hurricanes. A major hurricane is classified as a Category 3 or stronger. What is most concerning about the forecast is that experts anticipate an above average probability for major hurricanes making landfall along the U.S. coastline and in the Caribbean. 

Tropical Storm Andres develops, plus Atlantic Hurricane Season outlook

Tropical Storm Andres developed in the eastern Pacific Sunday morning. This is the earliest Tropical Storm to develop in recorded history in the eastern Pacific. The system is expected to remain over water and eventually weaken. This is a good reminder that the Atlantic Hurricane Season is right around the corner.

The 2021 Atlantic Hurricane Season begins in just under a month, on June 1st. It is time to begin talking about the tropics and preparing for the upcoming season. Despite the official June start date, May cannot be slept on. In 2020, there were two preseason storms. Arthur developed in the middle of May while Bertha developed during the end of May. Over the past decade (2011-2020), ten preseason storms have developed, which is the most in modern record-keeping.

The frequency of tropical cyclones steadily climbs from May to September 10th. Due to the frequency of tropical activity developing prior to June 1st, the National Hurricane Center will begin issuing tropical outlooks on May 15th. 

The 2021 Atlantic Hurricane Season is forecast to be above average. This coming off the most active hurricane season on record with 30-named storms and 6 hurricanes hitting the United States. One of the most well-known and prestigious outlooks was released several weeks ago. Colorado State University announced its 2021 Atlantic basin seasonal hurricane forecast and is expecting an above average season with 17 named storms, 8 hurricanes and 4 major hurricanes. A major hurricane is classified as a Category 3 or stronger. What is most concerning about the forecast is that experts anticipate an above average probability for major hurricanes making landfall along the U.S. coastline and in the Caribbean. 

One of the main factors favoring an above average season is the absence of El Niño. El Niño tends to create a hostile environment over the tropical Atlantic, disrupting the development and strengthening of tropical cyclones. Without El Niño, this favors an above average Atlantic season. Another factor favoring an above average season is warmer than average sea surface temperatures across the basin, especially near the main development region. Parts of the Atlantic ocean are 0.5-degrees warmer than average. Warm sea surface temperatures aid in the development and strengthening of tropical cyclones, which will help boost the numbers above average this season. 

Earlier this year, the northern and western Gulf of Mexico water temperatures were running below average due to the Arctic outbreak in February. Those temperatures have slowly recovered throughout March and April and are not expected to mitigate the numbers this season.

The 2021 forecast from CSU is slightly higher than their forecast last year. Their 2020 forecast predicted 16 storms, 8 hurricanes and 4 major hurricanes. The 2021 forecast from CSU will be revised at the beginning of June. Go ahead and begin preparing for hurricane season now. Create your hurricane kit and make sure your insurance is up-to-date.

Gulf of Mexico water temps to have big impacts on severe thunderstorms this spring

The northwestern Gulf of Mexico is still recovering from the February Arctic intrusion that impacted Texas. As of early-March, water temperatures are well below average. The below average water temperatures will undoubtedly have an impact on convection and severe thunderstorms west of the Mississippi throughout March.  

Current Gulf of Mexico Water Temperature

The Gulf of Mexico waters are an important variable in convection and severe thunderstorms for areas east of the Rockies. Generally speaking, when the Gulf of Mexico water temperatures are above average, this leads to more instability for convection and severe thunderstorms by supplying the atmosphere with added moisture and warmth. Instability acts as fuel for thunderstorms, and many times, the greater the instability, the stronger the thunderstorm if other variables are favorable. Thus, the added moisture and warmth bolsters instability, creating increased severe thunderstorms. 

Research shows the warmer the Gulf of Mexico water temperatures, the more hail and tornadoes occur throughout March, April, and May. With the water temperatures running below average in the northwestern Gulf of Mexico, it is possible this will have implications on convection and severe thunderstorms throughout the month of March due to the decreased availability of moisture and warmth added to the atmosphere. This may lead to less intense convection or a decrease in tornado and large hail frequencies during the month of March for areas west of the Mississippi River. It should be noted: severe thunderstorms are still possible throughout March but the frequency and intensity may be impacted. Areas farther east into Dixie Alley and the Southeast will likely not see a decrease in thunderstorm intensity and frequency as Gulf of Mexico water temperatures are above average in the eastern-half of the Gulf.

Above average temperatures are forecast for the region throughout March so this will allow the Gulf of Mexico water temperatures to slowly recover, possibly returning to average or even climbing above average by April, which could lead to an increase in severe weather during April and May.  

March Temperature Outlook

Hurricane Willa’s Remnants Will Have Large Impacts From Gulf States And Up The East Coast

Hurricane Willa is getting closer to the west-central coast of Mexico and should make landfall within the next few hours (Tuesday evening). Willa should retain major status until landfall. Willa will begin to weaken and lose its tropical characteristics as it moves across the higher terrain of Mexico into Texas but the remnants will remain well established to have large impacts from mid-week through the weekend for parts of the United States.

As the remnants move into Texas, deep moisture will stream northward throughout Texas into eastern New Mexico and Oklahoma. This will aid in heavy rainfall for this region with the greatest flood threat occurring in central and southern Texas, which has recently been inundated with rain. Widespread 1-3″ amounts are possible in eastern New Mexico and central and southern Texas with isolated 3-4″ amounts in central Texas near the Hill Country (see Fig. 1).

Fig. 1: 7-day rainfall forecast

The remnants will move out of Texas on Wednesday, merge with a shortwave, and begin to slowly intensify across the northern Gulf by Thursday. This will aid in thunderstorms and heavy rain for the Gulf States (from Louisiana to Florida) for late week. The low will then move off of the Southeast coast by late Friday and begin a north-northeastward forward movement off of the coast of the Carolinas. At this point, the low will begin to interact with an approaching cold front and deepen fairly quickly by Saturday morning as it spins off of the coast of the Mid-Atlantic. Heavy precipitation (see Fig. 1), rough seas and strong winds up to 30-60 mph (see Fig. 2)) will be possible for parts of the Mid-Atlantic and Northeast through the weekend. While coastal areas will see heavy rain (2-4″ are possible), areas further inland may see snow.

Fig. 2: Wind forecast Saturday evening

That is right, snow is possible as the nor’easter wraps in enough cold air for a transition to a heavy, wet snow. The best chance for snow will occur in interior parts of the Northeast down into the higher terrain of West Virginia. These areas may see a few inches of wet snow with several inches possible in the higher elevations of the Appalachians. Please keep in mind, we are a few days out so the snowfall forecast will likely need to be adjusted. A couple degrees cooler or warmer will have large impacts on accumulations and precipitation type.

Flooding is possible in Texas from this storm, which will impact travel. Turn around, don’t drown. Travel implications are also likely in parts of the Mid-Atlantic and Northeast due to wind and precipitation. With trees still having leaves on them, this increases the likelihood of them being overwhelmed for either wind or snow. This will increase the chances of power outages in this region over the weekend.

Hurricane Florence Forecast Update – Impacts Begin Tomorrow

Florence remains to be a powerful category 3 hurricane with maximum sustained winds of 120 mph. Some weakening has occurred today, but there will be one last window tonight and early tomorrow for Florence to have another shot at strengthening a bit before its center begins to reach the southern North Carolina/northern South Carolina coasts.

This will be a very brief article on some of the slight modifications that I made to my forecast.

The first image below shows the official track and cone of uncertainty from the National Hurricane Center. Their latest forecast has Florence making landfall along the southern coast of North Carolina before moving into South Carolina. I plotted their forecast on a county map, so that you can see it a bit better.

hurricane florence track

hurricane florence track county map

The Weather Prediction Center’s latest rainfall forecast indicates that 20+ inches of rain will fall along and just inland from the southern North Carolina/northern South Carolina coasts. Some regions could exceed 40 inches of rain. For those in any region that is forecasted to get around or above 4 to 6 inches of rain, take special note. The flooding situation that evolves will be the big story with Florence.

hurricane florence rainfall forecast

I made no changes to my landfall forecast from last night. It’s within the realm of possibilities that Florence could skirt southwest along the South Carolina coast once interacting with land, but I decided not to account for a possible second landfall that might occur. Getting into very technical details likely won’t change the overall impacts anyway.

hurricane florence landfall forecast

I made some modifications to my impacts map. I extended the pink zone, the region where I believe impacts could be severe, farther northeast along the North Carolina coast. Even though a landfall should occur farther southward, high storm surge will likely be very high well-away from the storm’s center to the right. I made no modifications to the pink zone in South Carolina. I’m not confident enough at this point that Florence won’t attempt to make a turn southwestward along the South Carolina coast. If I gain more confidence that for some reason that won’t occur, I’ll modify that part of the forecast tomorrow.

hurricane florence impacts map

Other than that, I trimmed back some of the red zone, the region where I believe at least some impacts could occur, for parts of Virginia. I made some subtle changes across Georgia, Tennessee, and West Virginia to include additional locations. Generally, the red region is where I believe tropical storm-force winds (or gusts) and/or flooding will occur. Since Florence is quite large and will slow significantly, that accounts for some of why that region is so large.

Please stayed updated on Firsthand Weather for future updates.

Hurricane Florence Likely To Be Catastrophic For Parts of the Carolina Coast

After Florence’s recent eyewall replacement cycle, it has re-strengthened into a 140 mph hurricane. Strengthening is expected to continue, given that vertical wind shear will be weak, sea surface temperatures will be more than sufficiently warm, and little dry air will be present to mix into Florence’s core. In an effort to answer many unanswered questions, I’ve made a couple of maps. Let me briefly explain what they mean.

The first map includes where I believe Florence will be making its (first) landfall. Some southern shifts in track could occur; thus, I’ve included the northern South Carolina coast as a potential landfall location. Given the fairly good consistency amongst the models on landfall location, I decided not to shift the landfall threat farther south. I’ll decide tomorrow if I need to make any additional shifts southward. Locations in and around the circled region is where I am currently anticipating damage to reach catastrophic levels.

Hurricane Florence landfall

The second map includes the regions that could be impacted by Florence, whether that’s from wind, flooding, or coastal storm-surge. Most of the forecast model guidance today made a noteworthy shift westward (and even southwestward) in Florence’s track once it reaches the southern North Carolina and northern South Carolina coasts. Some of the guidance even brings the center back over water and has a second landfall occurring farther southward into South Carolina. Weak steering flow is making this a particular challenging forecast. A high pressure ridge to Florence’s east/northeast and also to its west will result in Florence slowing significantly near the coast. The pink zone is where I’m currently most concerned about; while some parts of the red zone could experience significant impacts as well. At the least, I expect those in the red zone to experience some impacts from wind and rain. If the southward trend continues, I may end up chopping parts of northern Virginia out of the red zone, but in this update, I mainly included them due to potential flooding. I’m sure modifications will have to be made to the forecast, since we’re now getting down to the county-level.

Hurricane Florence impact zones

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