Hurricane Florence Trudges Along

Hurricane Florence is moving slowly towards North Carolina. The National Hurricane Center (NHC) is moving at northwest at 6 mph 5.2 knots 9.7 km/h. It has winds of 90 mph 78 knots 145 km/h with gusts as high as 113 mph 98 knots 182 km/h. That makes Florence a Category 1 hurricane. It is a large hurricane with hurricane force winds extending up to 80 miles 70 nautical miles 129 kilometers, while tropical storm force winds extend up to 195 miles 170 nautical miles 314 kilometers. A large hurricane is very dangerous as they can produce large storm surge and waves.

Looking at the wind swath map, the entire Coastal North Carolina and parts of South Carolina are experiencing tropical storm force winds. Some areas in Coastal North Carolina are seeing hurricane force winds. If Florence makes landfall with 90 mph winds, the highest wind on land is going to be 77 mph 67 knots 124 km/h with gusts as high as 116 mph 101 knots 187 km/h. Many areas will likely see 50 to 70 mph 44 to 61 knots 80 to 113 km/h with gusts as high as 75 to 105 mph 65 to 91 knots 121 to 169 km/h. The biggest question is where does Florence go ultimately.

It is the latest forecast track from NCAR-Tropical Cyclone Guidance for Florence. It is a heat map using points within 300 mile/480 kilometers radius. It is more circular, which suggests that Florence could linger for the next several days over land. That is going to be very bad as winds, storm surge, waves, and heavy rain are going to persist. Storm surge is getting much high as Florence gets closer. The Neuse River at Oriental, North Carolina gauge is setting high water of nearly 9 feet/2.7 meters!

It is only getting higher. I would not be surprised to see storm surge approaching 20 feet/6.1 meters or higher. Storm surge is very dangerous. That is why people evacuate from water and hide from the wind. To make matters worse, heavy rain is falling. Heavy rain leads to flooding, which kills like storm surge. It is very destructive. Case in point, Harvey. Let’s take a look at the rainfall total forecast. They are from EURO, GFS, Canadian, and German (ICON). The forecast models are from Weather.US. They are all seven day rainfall total forecast.

The forecast models have 29 to 38 inches/73.7 centimeters to 96.5 centimeters of rain. GFS has the lowest, while EURO has the highest. The NHC is forecasting 40 inches/101.6 centimeters of rain of rain. I would not be surprised if some areas see 50 inches/127 centimeters of rain. Some areas have gotten over 12 inches/30.5 centimeters of rain already! 50 inches does not sound so off.

Here is what I think will happen.
-Florence is making landfall somewhere in North Carolina.
-Landfall time is looking to be Friday morning.
-Strong winds, storm surge, and heavy rain will be the main problem from Florence.
-Main headline for Florence will likely be massive flooding.
-Record rainfall is likely with Florence.

It is going to be a long night for North Carolina with Florence. It is going to be one brutal hurricane for them.

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Hurricane Ike 10 Years Later

Before Harvey flooded out Southeast Texas, there was Ike. It is hard to believe it has been 10 years since Hurricane Ike made landfall on Southeast Texas as a monsterous Category 2 hurricane in the early morning hours of September 13, 2008. Especially the fact this comes in light of Harvey. Ike pelted Southeast Texas and Southwest Louisiana with hurricane force winds and heavy rain. Ike was the last hurricane to hit Texas prior to Harvey. Almost a nine year gap of no hurricanes hitting Texas, let alone a major hurricane. The last major hurricane to hit Texas prior to Harvey was Bret in 1999, which is 18 years.

Thunderstorms over Sudan that later became Ike.

What is the origin of Hurricane Ike? Ike started as a mesoscale convective system (MCS) that formed over Sudan on August 19th. Most tropical waves come from thunderstorms that form in the Northeast part of Africa. They are set off by the Intertropical Convergence Zone (ITCZ) or monsoon. The ITCZ is where there is thunderstorms from the clash of trade winds. These thunderstorms often provide beneficial rains in tropical and subtropical areas. The thunderstorms in ITCZ can break away and travel away. One of those thunderstorms from the ITCZ managed to do that. The MCS traveled over Africa and entered the Atlantic Ocean as a tropical wave on August 29th. The tropical wave traveled across with multiple vortices competing. One of them would win out as the thunderstorms in the tropical wave get better organized on September 1, 2008. It is upgraded to Tropical Depression #9. Later that day, it is named Ike as it travels over the open Atlantic. Tropical Storm Ike has to deal with wind shear in the upper level early in its life. The wind shear blows tops of thunderstorms, especially westerly wind shear. Since 2008 season is Neutral to La Nina, conditions are more favorable as there is less westerly wind shear. If 2008 was El Nino, there would be more westerly wind shear, which is why generally El Nino Atlantic Hurricane seasons see less storms. Wind shear generally kills tropical development. The higher the storm clouds are, the cooler it is. Higher storm clouds also mean they are more intense.

However, Ike gets a reprieve as the wind shear weakens and encounter warmer waters on September 3rd. This allows Ike to rapidly intensify into a major hurricane. By the next day, Ike becomes 2008’s strongest hurricane with 145 mph 126 knots 233 km/h winds and central pressure of 935 millibars. Ike’s strength did not last as it encountered wind shear on September 5th. The wind shear weaken Ike to Category 2 strength.

Hurricane Ike around its peak.

Ike is pushed southwards into more favorable areas due to upper level ridge to the north. Ike becomes a Category 4 hurricane as conditions are more favorable. As it goes westward, Ike made its first landfall on Turks and Caicos Islands as a Category 4 hurricane on the early morning hours of September 7th. The Turks and Caicos Islands are the first to feel Ike’s violent wrath in the form of strong winds, heavy rain, storm surge, and high waves. The South Caicos and Grand Turk take the brunt of Ike. Despite Ike’s fury, there are no reports of fatalities.

Damage in Grand Turk.

While Ike is ravaging the Turks and Caicos Islands, the outer bands of Ike are dumping heavy rain on Haiti and Dominican Republic, which have been ravaged by Fay, Gustav, and Hanna. The flooding from Ike claims 74 lives in Haiti and 2 in Dominican Republic. Prior to Ike, Tropical Storm Hanna ravaged Haiti and Dominican Republic with heavy rain that led to massive flooding. The flooding claims 529 lives in Haiti, while just one dies in Dominican Republic. Why did Haiti see more fatalities than Dominican Republic? The lack of trees in Haiti makes it even more vulnerable to mudslides from the mountains. The heavy rain causes deadly mudslides that destroys houses and kill people.

Stranded Cubans following Ike.

Once Ike passes Turks and Caicos Island, Ike heads for Cuba. The hurricane makes landfall on Cabo Lucrecia, Holguín Province, Cuba. Cuba is in a very rough ride with Ike as it traverses over the entire island nation. Cuba is being pelted by heavy rain, strong wind, high waves, and storm surge. Briefly, Ike goes over the water only to make a second landfall on Punta La Capitana, Pinar del Río, Cuba on September 8th as a Category 1 hurricane. Ike claims 7 lives in Cuba.

Ike near its secondary peak in Gulf of Mexico.

Once Ike exits Cuba, it is a large Category 1 hurricane. Ike traveling over all of Cuba caused the storm to expand as energy is spread out from land interaction. It also disrupted Ike’s core. Ike enters large area of warm water in the Gulf of Mexico and is getting close to the Loop Current, which is one of the warmest spot. Ike rapidly deepen from 963 to 944 millibars on the night of September 10th as it was over the Loop Current. However, the wind did not strengthen much, only from 80 to 100 mph 70 knots to 87 knots 128 km/h to 161 km/h. The reason is Ike is a very large hurricane with hurricane force winds extending up to 125 miles 109 nautical miles 201 kilometers from the eye. The pressure gradient is not tight due to its large size. Normally, an Atlantic hurricane with central pressure of 944 millibars is a Category 3 or 4 hurricane.

On September 11th, as America remembers and reflects the seventh anniversary of the 9/11 Terrorist Attacks, Southeast Texas is sunny and dry. The west side of a hurricane in the Northern Hemisphere is usually the “clean” side. It blows in dry and sinking air from the north. The nice sunny day is very deceptive as Ike is ever inching closer. Meanwhile in the Gulf of Mexico, Ike is generating massive waves that are heading towards the Texas and Louisiana. Ike continues across the Gulf of Mexico as a large Category 2 hurricane. Waves are coming ahead of Ike in coastal Texas. People are evacuating from coastal areas including Galveston. Some choose to stay behind. The outer cloud banks of Ike are over Southeast Texas as winds start to pick up. By the afternoon of September 12th, some coastal areas are getting squally weather from the feeder bands entering Texas.

By the night of September 12th, conditions have gotten much worse. Meanwhile in Houston area, it is still windy with occasionally light rain. As the night progresses, Ike is getting closer to landfall. The hurricane force winds enter Texas around the late hours of September 12th. Ike is getting stronger and developing a more organized eyewall. Ike now has a central pressure of 951 millibars and 110 mph 96 knots 177 km/h winds. Ike is a large hurricane with hurricane force winds extending up to 125 miles and tropical storm force winds extending up to 260 miles 226 nautical miles 418 kilometers.

Ike at landfall on Southeast Texas.

Highest wind gust possible based on multiplying by factor of 1.5.

By the early morning hours of September 13th, Houston area is seeing stronger winds and heavier rain. Power starts to go out throughout Southeast Texas as power lines are being knocked by the strong wind. The coastal areas are seeing storm surge getting higher and higher. Anyone who stayed behind in Galveston or Bolivar Peninsula are doomed by the massive storm surge. Ike makes landfall on the eastern end of Galveston Island at 2:10 AM Central Time. People who are staying behind in the coastal areas are wishing they had evacuated as they are surrounded by rising storm surge. Ike travels to the northwest towards Houston. By 4:00 AM, Ike is over Baytown, which is flooded by storm surge. A large area of Southeast Texas is getting hurricane force winds including all of Houston.

Highest sustained winds during Hurricane Ike.

Bolivar Peninsula following Ike.

By the time the Sun rises, Ike is still ravaging Southeast Texas despite the fact it has weakened to Category 1 hurricane. Ike remains a monsterous and very dangerous hurricane. Many areas are still seeing heavy rain and strong winds. The wind blow down numerous trees and damage many buildings and houses. There is widespread flooding reported throughout Southeast Texas. Bayous and rivers are overflowing from widespread heavy rain. Coastal areas had storm surge as high as 25 feet/7.6 meters. It is one of the highest storm surge recorded in America and highest in Texas. It exceeds Camille, but below Katrina. Bolivar Peninsula saw the highest storm surge as the whole area looked like if a nuclear bomb had exploded. Once it is all over, many buildings and houses are damaged or destroyed, while many trees are uprooted. Coastal areas are utterly gutted from the massive storm surge. Millions of people are out of power for days. A large area saw 6 to 12 inches/15.2 to 30.5 centimeters of rain from Ike.

The damage is not just limited to Texas. Louisiana also felt the brunt of Ike, especially in Southwestern Louisiana. It is the same area that had been ravaged by Hurricane Rita in 2005. Many areas are flooded by Ike. There is even flooding in New Iberia, which is in Central Louisiana. It shows that Ike’s massive size had a huge impact over a large area from Texas to Louisiana. This is despite the fact that they only got tropical storm force winds. It shows that large, but not so strong hurricane is very dangerous as it produces massive storm surge and high waves.

Thunderstorms ahead of a cold front in the early morning hours of September 14, 2008.

The following night, a cold front passes, which allows thunderstorms to form from moisture left by Ike. The storms dumped 5 to 8 inches/12.7 to 20.3 centimeters of rain. The heavy rain causes more flooding on top of what Ike dumped in Southeast Texas. Once the rain ended, many areas saw a two day total ranging from 10 to 20 inches/25.4 to 50.8 centimeters of rain. Meanwhile, the remnants of Ike continue to wreak havoc in the Midwest. Ohio see hurricane force gusts, which causes more power outages. The remains of Ike continue into Canada and dump heavy rain in Ontario and Quebec. A total of 112 people lost their life with 34 unaccounted for in America. Most of the deaths are in Texas, where 84 people died.

Rainfall total from September 12, 2008 to September 15, 2008.

So, how was 2008 like prior to Ike. The winter of 2007-2008 is La Nina, so it is warmer and drier. Despite the La Nina, there are storms. Spring of 2008 is mostly dry. There were days of pleasant weather in Spring 2008. Summer of 2008 is average in terms of temperature and rainfall. Texas first brush with a hurricane is Dolly, which affected South Texas. The outer bands of Dolly dump heavy rain in the Houston area. Not too long after Dolly came, Tropical Storm Edouard pays a visit to Houston area. It is a rather unremarkable tropical storm that dumps up to 6 inches of rain. Edouard moves inland and gives beneficial rains to drought ridden Central Texas.

NHC Hurricane Ike Report
NHC Hurricane Ike Advisory Report
Morphed Integrated Microwave Imagery at CIMSS (MIMIC)

Furious Florence And Future Kirk?

Hurricane Florence is getting ever so closer to the Southeastern US. Subtropical Storm Joyce recently formed in the Eastern Atlantic. We now have Florence, Helene, Isaac, and Joyce. Invest 95L could become Kirk. If Kirk forms, we would have five storms at once. Before I talk about the latest, ten years ago today, Hurricane Ike was getting closer to the Texas Coast as a large Category 2 hurricane. I will focus on Florence and Invest 95L as they are closest to land.

The National Hurricane Center (NHC) has Florence with 110 mph 96 knots 177 km/h winds with gusts as high as 138 mph 120 knots 222 km/h. It has central pressure of 957 millibars. Just because Florence is no longer a major hurricane does not make it any less dangerous. In some ways, it is more dangerous as it gets larger. People might think that Florence is no longer dangerous as it is no longer a major hurricane. It has hurricane force winds extending up to 80 miles 70 nautical miles 129 kilometers and tropical storm force winds extending up to 195 miles 170 nautical miles 314 kilometers. Hurricane that go further north, tend to get larger. I think Florence could have hurricane force winds extending up to 125 miles 109 nautical miles 201 kilometers and tropical storm force winds extending up to 250 miles 217 nautical miles 402 kilometers before landfall.

Here is the latest forecast track from NCAR-Tropical Cyclone Guidance for Florence and Invest 95L. It is a heat map using points within 300 mile/480 kilometers radius. I have included Ensemble Prediction Systems generated from a previous forecast cycle along with the latest.

The heat map for Florence is getting more circular, which is concerning. Florence could make landfall somewhere in South Carolina or North Carolina. It suggests that Florence is going to slow down after it makes landfall. It looks to linger over the area after landfall. As for landfall time, Florence is probably going to make landfall sometimes on Friday morning. The slower motion of Florence is lower confidence because forecast models cannot predict where Florence will go. In regards to Invest 95L, it looks to be making landfall on South Texas sometimes on Friday. Too early to tell for this one at this time. Since Florence is getting larger and forecasted to slow down, storm surge is going to be a serious problem.

Some areas could see easily 15 feet/4.6 meters storm surge. I would not be surprised if some areas see over 20 feet/6.1 meters storm surge. If anyone is in a storm surge area, they need to evacuate. Storm surge kills! Most people die from storm surge in hurricanes and tropical cyclones. The deadliest tropical cyclone known is the 1970 Bhola Cyclone, which claimed 1.1 million people in present day Bangladesh, then East Pakistan on November 12, 1970. The tropical cyclone produced up to 33 feet/10 meters storm surge on the Ganges Delta. Most of the death were from deadly storm surge and epidemic following the tropical cyclone. Proof that storm surge kills. It also does not have to be a strong major hurricane to produce deadly and monsterous storm surge. Ike and Sandy produce high storm surge despite not being major hurricanes. They produced deadly storm surge because they were large storms and the geography is more conducive to deadly storm surge, which is also the case for Coastal Bangladesh. As Florence getting closer and water rising, many are asking how strong will Florence be.

Most intensity forecast models for Florence show it will be maintaining Category 2. One has it re-intensifying into Category 3 hurricane. I would not be srurprised if Florence does intensify into a Category 3 before landfall. As for Invest 95L, a couple forecast models have it intensifying into a tropical storm. I would not be surprised if 95L becomes Kirk by Thursday.

Rainfall is another concern, especially for Florence. They are from EURO, GFS, Canadian, and German (ICON). The forecast models are from Weather.US. They are all seven day rainfall total forecast.

The EURO has nearly 40 inches/101.6 centimeters of rain. The GFS has 33 inches/83.8 centimeters of rain. The Canadian has nearly 22 inches/55.9 centimeters of rain. The ICON has 28 inches/71.2 centimeters of rain. The EURO has the heaviest rainfall forecast. Previously, the GFS had some high rainfall forecast totals as high as 77 inches/195.6 centimeters in 7 days! The National Hurricane Center forecasts rainfall on par with Mitch and Harvey. They forecasted over 40 inches/101.6 centimeters of rain. That is very chilling to read that. Not often you see that for sure. I would not be surprised if some areas get over 50 inches of rain once it is all over.

The rainfall forecast for Invest 95L is not as high as it has been previously. The EURO has 6 inches/15.2 centimeters of rain. The GFS has 5 inches/12.7 centimeters of rain. The Canadian has nearly 7 inches/17.8 centimeters of rain. The ICON has over 10 inches/25.4 centimeters of rain. The forecast models are all over the place for Invest 95L. The forecast models assume that 95L does not become Kirk. If it became Kirk, I suspect the forecast models are going to change.

Here is what I think will happen.
-Florence could intensify into a Category 3 hurricane.
-Florence is looking to affect South Carolina and North Carolina the most.
-Strong winds, storm surge, and heavy rain will be the main problem from Florence.
-Main headline for Florence will likely be massive flooding.
-Invest 95L is likely to become Kirk by Thursday.

The Tropics Are Heating Up

Today is what is the peak date for the Atlantic Hurricane Season. No doubt today with Florence, Isaac, Helene, and Invest 95L, which maybe Joyce. 95L is an area of thunderstorms over the Caribbean south of Cuba. Tomorrow is September 11, which is the 17th anniversary of the devastating terrorist attacks in New York, Arlington, and Shanksville. It claimed 3,000 lives and reduced the World Trade Center to a smoldering and toxic rubble and left the Pentagon burning shooting out toxic smoke. I will be focusing on Florence as it is most likely to pose a threat to America. Invest 95L was declared earlier today, so there is not a lot of forecast models for it yet.

As of 11:00 PM AST from the National Hurricane Center (NHC), Florence has 140 mph 122 knots 225 km/h winds with gusts as high as 175 mph 152 knots 282 km/h. The central pressure is 944 millibars. It is a medium sized hurricane with hurricane force winds extending up to 40 miles 35 nautical miles 64 kilometers and tropical storm force winds extending up to 150 miles 130 nautical miles 241 kilometers.

The forecast intensity shows Florence being a Category 4 hurricane.

I think Florence will be a Category 5 hurricane. Here is why from NOAA-Tropical Cyclone Heat Potential and Weather Maps-Maximum Potential Hurricane Intensity.

The water where Florence is and probably where it will go is warm. It has plenty of warm and deep water to work with. The Maximum Potential Hurricane Intensity (MPI) supports a Category 5 hurricane if conditions are near perfect. This is despite the fact that Florence is likely to run into UW-CIMSS-Wind Shear. The wind shear is not that strong and since Florence is well structured and organized, it should have little effect.

The biggest question is where does Florence go? That is on everyone’s mind right now. The forecast paths are from NCAR-Tropical Cyclone Guidance.

I have the latest forecast track and ensemble from a previous forecast cycle. The consensus on both forecast models including the ensembles using the heat map within 300 mile/480 kilometers radius from the point show that North Carolina is most likely to have Florence making landfall later this week. What is most concerning is once it is over land, Florence could slow down and stall out. This leads to heavy rain and dangerous flooding. Hurricane Harvey lingered over Texas dumping heavy rain over a large area leading to massive flooding. Here are rainfall forecast models from Weather.US. They are EURO, GFS, Canadian, and German (ICON). They are all seven day rainfall total forecast.

The forecast models all agree that heavy rain will fall over North Carolina. Two have heavy rain over Virginia. The EURO has 19 inches/48.3 centimeters of rain. The GFS has (drum rolls please) 77 inches/195.6 centimeters of rain! Thankfully, that is over the ocean. North Carolina has 15 to 20 inches/38.1 centimeters to 50.8 centimeters of rain, which is still heavy. The Canadian has 39 inches/99 centimeters of rain. Like the GFS, it is over the ocean. The ICON has 29 inches/74 centimeters of rain. The 77 inches of rainfall forecast from GFS is assuming that Florence is stalled out over the ocean. If Florence was to stall out over land and 77 inches of rain did fall, it would be heavier than Harvey. I have never seen such high rainfall forecasts. The last time I saw something that high high was from Harvey. Some forecast models I saw had up to 70 inches/177.8 centimeters of rain over Texas!

The rainfall forecast does include Texas. They are all over the place in terms of rainfall forecast for the next 7 days. The EURO has 19 inches of rain west of Corpus Christi. The GFS has 5 inches/12.7 centimeters. The Canadian has 12 inches/30.5 centimeters of rain over Houston area. The ICON has 15 inches of rain northeast of Corpus Christi. This suggests at this point, the heaviest rain will be in South Texas depending on how organized Invest 95L. If it is not as organized, the heaviest rain would be east of the center and Southeast Texas would get the heaviest rain from 95L.

Here is what I think will happen.
-Florence could intensify into a Category 5 hurricane.
-Florence is looking to affect North Carolina the most.
-Strong winds, storm surge, and heavy rain will be the main problem from Florence.
-Deadly flooding will probably be main headline if Florence stalls out.
-Regardless if Invest 95L is Joyce or not, Texas could see more heavy rain this week to early next week.

Lane’s Wrath

Hurricane Lane is a strong Category 3 hurricane with 125 mph 109 knots 201 km/h winds. It has gusts as high as 150 mph 130 knots 241 km/h. The latest satellite image of Lane shows the hurricane is less intense as it is less organized than last night. It suggests that Lane is weakening, but that does not reduce the danger of Lane. Hawaii would have to deal with strong winds, high waves, storm surge, and heavy rain.

Most forecast models have Lane weakening to a Category 1 hurricane to tropical storm as it gets closer to Hawaii this weekend. As mentioned previously, satellite presentation does suggest Lane is weakening. The next question is is it possible that Lane could make landfall?

The heat map forecast from various forecast models from NCAR-Tropical Cyclone Guidance with radius of 300 miles. It is possible that Lane could make landfall somewhere on Hawaii. It could be Oahu, Moloka’i, and Lana’i. That would be very bad it Lane made landfall on Oahu, which is the most populated Hawaiian island. It looks to be lingering for the next several days as it is a slow moving hurricane. That would be a problem as slow moving tropical cyclones dump heavy rain. Case in point, Harvey. One huge concern is flooding from Lane, regardless of intensity.

The rainfall forecast models are from GFS, Canadian, EURO, and ICON. They are all 7 day rainfall total forecast from Weather.US.

The rainfall amount forecast is all over the place. Let alone where the heavy rain falls. Most have 10 to 20 inches/25.4 to 50.8 centimeters of rain falling. ICON has the lowest with 13 inches/33 centimeters of rain, while EURO has nearly 36 inches/91.4 centimeters of rain, which is over Mauna Kea and Mauna Loa. The mountainous terrain is conducive to deadly mudslide and flooding. Also, mountainous areas have heavier rain. I would be more concerned about heavy rain and flooding from Lane than strong winds. Doppler radar out of NWS Hawaii shows heavy rain is already falling in parts of Hawaii as of 5:15 PM Hawaiian Time.

Doppler radar estimate out of Kohala show up to 15 inches/38.1 centimeters or higher has fallen already from Lane. There is no doubt that 36 inches/91.4 centimeters is likely to fall in Hawaii. I would not be surprised if some areas see up to 50 inches/127 centimeters of rain once it is all over. That is very concerning. The live camera from Waikiki Beach shows a calm beach despite Lane coming ever so closer. Come tomorrow and Saturday, it will be very different.

Here is my take.
-Oahu, Maui, and Kauai could be impacted by Lane as early as Friday.
-Strong winds, heavy rain, high waves, and storm surge will be a major problem.
-Flooding, not strong winds, will be the main problem.

More Rain Tonight?

The tropical wave is now over Texas. It is a disorganized system, so it is hard to predict where the rain will be tonight. Let’s look at High-Resolution Rapid Refresh (HRRR), North American Mesoscale Forecast System (NAM), Regional Model (RGEM), and Weather Research and Forecast (WRF-ARW, and WRF-NMM). They are at 0900Z or 4:00 AM CDT.

The HRRR has heavy rain mostly west and southwest of Houston. The NAM has heavy rain over Matagorda Bay and east of Houston. The RGEM has an axis of heavy rain from Corpus Christi area to East Texas. The WRF-ARW has the heavy rain over Matagorda Bay. The WRF-NMM has heavy rain south of San Antonio. This shows that forecasting where heavy rain will fall tonight is all over the place with this tropical wave.

Looking at the most recent Doppler radar mosaic, there is heavy rain over East Texas and Southwest Louisiana. It is not really active right now.

However, with tropical moisture, thunderstorms tend to form at night, especially near the center of the low pressure system. They are called core rains and they can dump heavy rain in a short time. Harvey, Allison, Claudette, and Thrall 1921 Flood were core rain events as flooding rain fell at night. This system is disorganized, so it will be hard to tell where it will exactly form. Some forecast models want the heavy rain over Matagorda Bay, while some have it over Southeast Texas.

Many are wondering what is the forecasted rain amount. The rainfall forecast models are from GFS, Canadian, EURO, ICON, and Weather Prediction Center (WPC). They are all 7 day rainfall total forecast.

The GFS has 4 inches of rain over Galveston Bay. The area of heaviest rain is east of Houston.

The Canadian has nearly 11 inches of rain just north of Houston. The largest area of heavy rain is north of Houston.

The EURO has backed down on nearly 30 inches of rain. It has nearly 15 inches of rain south of San Antonio. There is a large area of heavy rain southwest of Houston.

The ICON has over 13 inches of rain near Aransas Pass. There is an area of 8 inches of rain west of Houston. Most of the heavy rain is over the Gulf Of Mexico.

The WPC has 10 inches of rain over an Matagorda Bay and Victoria. Houston area has 5 to 7 inches of rain.

The rainfall forecast is all over the place on where it will fall and even the amount. This is a very frustrating forecast. Regardless of forecast models, all forecast heavy rain will fall somewhere.

Here is what I think will happen.
-Someone will see heavy rain tonight.
-Not ruling out Houston area getting heavy rain tonight.
-Rainfall amounts could range from 5 to 10 inches of rain with isolated totals approaching and exceeding 15 inches.

The forecast models came from Weather.US, Tropical Tidbits, National Hurricane Center, and National Weather Service. Special thanks to all of them.

Invest 91L As This Weekend’s Rainmaker?

Invest 91L is over the Gulf of Mexico. Currently on satellite from CIMSS-Tropical Cyclones, it does not look too impressive.

Of course with tropical lows, they tend to fire up at night as they are warmer than the surrounding area. I would not be surprised to see a lot of thunderstorms come morning. As the time passes, where does Invest 91L go?

Most forecast models have it going towards South Texas or Mexico. There is a chance that it could go over Southeast Texas. If it goes into Mexico or South Texas, there is better chance for rain since the northeast side is the wettest as it is the “dirty” side of the tropical low. The intensity forecast models are split.

Some have Invest 91L as a tropical wave. Some have it intensifying into a tropical depression. Some have it becoming a tropical storm. If it becomes a tropical storm, it would be Beryl. Like I say, intensity forecast is not really reliable. At this point, I would be more concerned with the rain than some tropical storm developing.

Various forecast models have different rain amounts, which are from GFS, Canadian, EURO, and Weather Prediction Center (WPC). They are from Weather.US and Weather Prediction Center (WPC)-Quantitative Precipitation Forecasts (QPF). These are 7 day rainfall totals.

The GFS has the heaviest rain over Houston area. It forecasts up to 8 inches of rain. A large area of Southeast Texas has 3 to 6 inches of rain.

The Canadian forecasts rain amounts of up to 6 inches over Austin area and around Halletsville.

The EURO forcasts up to 20 inches of rain southeast of San Antonio. There is 10 inches south of Houston. The EURO is the wettest of the forecast models.

The WPC has up to 5 inches of rain over Southeast Texas. It is the driest of the forecast models.

All the forecast models have rain for Texas. The only difference is the amount. Some are very bullish, while others are not. The plus side is that it will put a dent on the drought in Texas.

Most areas in Texas are in a drought. The rains can alleviate the drought, which is a good thing. This also increases the risk for flooding, which is not good almost a year after Harvey ravaged Texas with epic rainfall.

I think Invest 91L will be more of a rain event this weekend. Tropical development is not likely, but cannot be ruled out. Regardless, Invest 91L needs to be watched as it could be more of a rain event that may cause flooding in some areas.

The forecast models came from NCAR-Tropical Cyclone Guidance. The GIS drought map is from United States Drought Monitor.