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.

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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.

Nate Is Edging Closer To The Gulf Coast

Nate is now a Category 1 hurricane with 90 mph 144 km/h 78 knots wind. Further strengthening is possible with Nate. The question is how strong will Nate be by landfall.

Most forecast models have Nate intensifying into Category 2 with one intensifying into Category 3 hurricane. I would not be surprised if Nate becomes a Category 3 hurricane upon landfall. Category 4 or 5 is highly unlikely as it is moving quickly at 26 mph 42 km/h 22.6 knots. Here is a forecast model of where Nate will possibly make landfall. The heat map is from within 300 miles (480 kilometers) of a point.

There is a consensus that Nate could make landfall southwest of New Orleans to Pensacola area. It is unlikely Nate could deviate and hit Harvey ravaged Texas Coast. At this rate, Nate could make landfall later tonight or early tomorrow morning. Tropical storm force winds could start later this afternoon to evening.

Nate is not a large hurricane. Here is a wind radii map of Nate.

Hurricane force winds are only on the east side of Nate. Hurricane force winds are up to 69 miles 110.4 km 60 nautical miles across from northeast to southeast quadrant. Tropical storm force winds are are up to 230 miles 368 km 200 nautical miles across from northeast to southeast quadrant. However, since Nate is moving quickly, hurricane force winds maybe felt up to nearly three hours on the eastern side of Nate. Tropical storm force winds maybe felt up to nine hours.

The motion Nate is moving at, many areas could see 4 to 8 inches/10.2 to 20.3 centimeters of rain with isolated totals as high as 12 inches/30.5 centimeters. The forward motion should keep inland flooding risk low at this time.

Here is what I think will happen.
-Nate will make landfall somewhere along the Gulf Coast.
-Coastal flooding will be the main problem.

The forecast models came from NCAR-Tropical Cyclone Guidance and National Hurricane Center. Special thanks to all of them.

Puerto Rico In Trouble

Hurricane Maria is a very dangerous Category 5 hurricane with 175 mph 280 km/h 152 knots. It has a central pressure of 909 millibars (mb). This is more intense than Hurricane Irma in terms of central pressure. Maria is now the top 10 most intense Atlantic hurricane known. I mean known as records go back to 1851.

Top 10 Most Intense Hurricane By Central Pressure
1.) Wilma 2005 882 mb
2.) Gilbert 1988 888mb
3.) Labor Day 1935 892 mb
4.) Rita 2005 895 mb
5.) Allen 1980 899 mb
6.) Camille 1969 900 mb
7.) Katrina 2005 902 mb
8.) Mitch 1998/Dean 2007 905 mb
9.) Maria 2017 909 mb
10.) Cuba 1932/Ivan 2004 910 mb

Wilma is the most intense hurricane to date. It ravaged Yucatan Peninsula and Florida. Gilbert and Rita caused a huge scare for Texas. Gilbert hit Jamaica, Yucatan Peninsula, and Mexico’s Gulf Coast. Rita hit east of Houston area in East Texas and Southwest Louisiana. Labor Day 1935 Hurricane likely had low central pressure. Allen made landfall on South Texas. Camille and Katrina ravaged the Gulf Coast in the same area. Katrina was larger as it produced higher storm surge in Mississippi and flooded out New Orleans. Mitch killed 22,000 from heavy rain and massive flooding in Central America. Mitch is the deadliest hurricane after the Great Hurricane of 1780, which claimed 30,000 lives. Dean hit Yucatan Peninsula and Mexico. Cuba 1932 is Cuba’s deadliest hurricane to this day. Ivan ravaged the the Caribbean before making landfall on Alabama and Florida. Ivan came back again and made landfall as a tropical storm on Texas/Louisiana border. That being said, Maria is getting ever so closer to St. Croix and Puerto Rico.

Doppler radar image out of Puerto Rico shows a formidable Hurricane Maria. Not often we see a Category 5 hurricane on ground based Doppler radar. It has a near prefect circular eye. The infrared satellite image of Hurricane Maria is very impressive and scary. It is going to be a rough night for St. Croix.

St. Croix is experiencing tropical storm force winds. Hurricane force winds should be later tonight for St.Croix. Puerto Rico should feel tropical storm force winds later tonight. Hurricane force wind comes early tomorrow morning. Hurricane force winds are up to 104 miles 166 km 90 nautical miles across from northwest to northeast quadrant. Tropical storm force winds are are up to 276 miles 442 km 240 nautical miles across from northwest to northeast quadrant. It has gotten larger from yesterday. The speed Maria is moving at, 10 mph 16 km/h 8.7 knots, tropical storm force winds could last up to nearly 28 hours, while hurricane force winds could last up to 10 hours. This prolonged wind could do a lot of damage for Puerto Rico and St. Croix.

Here is the heat map forecast from various forecast models and GFS ensemble track guidance for Maria up close with Puerto Rico.

It does not look good for Puerto Rico. Most of the forecast models have Maria making landfall and going over Puerto Rico. The intensity as it is is very concerning. I would not be surprised if Maria intensifies further right before it gets close to Puerto Rico later tonight. This is a very bad for Puerto Rico. If Hurricane Maria makes landfall as a Category 5 on Puerto Rico, it will be the first since 1928, the Okeechobee Hurricane. On September 13, 1928, the Okeechobee Hurricane made landfall on Puerto Rico as a Category 5 hurricane with 160 mph 256 km/h 139 knots. The gusts are as high as 240 mph 384 km/h 209 knots. It had a central pressure of 929 millibars. It was very likely the central pressure was lower and stronger. The hurricane was large as it ravaged Puerto Rico. The hurricane claimed 312 lives in Puerto Rico, while 1,200 lives were lost at Guadeloupe. The Okeechobee Hurricane made landfall near West Palm Beach as a Category 4 hurricane with 145 mph 232 km/h 126 knots on September 17, 1928. The highest wind on land would be around 123 mph 200 km/h 107 knots with gusts as high as 185 mph 296 km/h 161 knots. The hurricane stayed over Florida and claimed at least 2,500 lives and likely more. The Okeechobee Hurricane claimed more than 4,000 lives. The death toll is likely much higher. It is America’s deadliest hurricane since 1900 Galveston Hurricane that claimed 12,000 lives. In fact, Okeechobee Hurricane is the deadliest American disaster prior to 9/11 and Hurricane Katrina.

Once Maria passes Puerto Rico, where does it go?. This is the latest heat map from various forecast models and GFS ensemble track guidance for Maria. The GFS goes up to 10 days.

The forecast models have a westward trend from 24 hours ago. Dominican Republic and Bahamas could feel the impact of Maria. There is also a possibility that Maria could affect North Carolina and the Eastern Seaboard. That would be too early to tell at this time. This is on top of how strong Maria will be.

Most of the forecast models have Maria weakening after it passes Puerto Rico. One model has Maria intensifying back to a Category 5 hurricane in three days. Intensity forecast are notoriously difficult to forecast. All the forecast models are subject to change.

Here is what I think will happen.
-Maria could pose a major threat to Puerto Rico.
-Maria will likely impact Dominican Republic.

This is going to be very bad for Puerto Rico and St. Croix. I fear the damage will be epic and the death toll could be high. This comes at a bad time as Puerto Rico is mired in a serious financial crisis. This could make recovery difficult for Puerto Rico. I cannot imagine what it will be like during Hurricane Maria.

The forecast models came from NCAR-Tropical Cyclone Guidance, NOAA Tropical Cyclone Imagery – Storm Floaters, National Hurricane Center, and National Weather Service. Special thanks to all of them.

Irma Ravages Florida Part 2

The National Hurricane Center (NHC) has Hurricane Irma is near Tampa and it is a Category 2 hurricane with 100 mph 160 km/h 87 knot winds, which is on land 85 mph 136 km/h 74 knots. Gusts are as high as 128 mph 205 km/h 111 knots. Hurricane force winds are up to 150 miles 240 km 130 nautical miles across from northeast to southeast quadrant. Tropical force winds are up to 690 miles 1,104 km 600 nautical miles across from northwest to northeast quadrant. It is a large hurricane!

Tropical storm force winds are engulfing a large portion of Florida. It is even felt in Georgia and South Carolina! That is how large Irma is. Irma got large because it is over land, which disrupts the core. There is also a cold front. Those two make Irma larger as energy is spread out. The same reason why Ike got larger before making landfall on Texas in 2008.

Irma continues to get closer to Tampa. Here is the forecast model of where Irma will go. This is the latest heat map from various forecast models and GFS ensemble track guidance for Irma. The GFS goes up to 10 days.

Interesting to note there is not much of a consensus of where Irma will go. Interestingly, there appears to be some cluster where Irma will go in the next five days. Looks like Irma may end up over Tennessee, Kentucky, Mississippi, Alabama, Arkansas, Indiana, and Illinois.

Here is what I think will happen.
-Tampa Bay Area will be ravaged by Irma.
-Storm surge and strong winds will be the main issue.
-Flooding from storm surge and heavy rain will be widespread.

The forecast models came from NCAR-Tropical Cyclone Guidance and National Hurricane Center, . Special thanks to all of them.

Irma Ravages Florida

Hurricane Irma made landfall made landfall on Cudjoe Key, Florida as a Category 4 hurricane with 929 millibars. It is moving north at 9 mph. Irma is a very large hurricane.

The Southeast Doppler mosaic has Irma engulfing a large portion of Florida. Many areas are getting heavy rain and strong winds. Hurricane force winds are up to 138 miles 221 km 120 nautical miles across from northwest to northeast quadrant and northeast to southeast quadrant. Tropical force winds are up to 437 miles 699 km 380 nautical miles across from northwest to northeast quadrant. Irma has gotten larger, which is a bad thing.

Hurricane force winds are felt in Southern Florida from Monroe, Miami-Dade, and Collier County. Many areas are reporting hurricane force winds. A crane had collapsed in Miami and storm surge is higher than forecasted. This is despite the fact that Irma is west of the area. This puts Miami over the dirty side. This leads to the next question, where does Irma go? Here is the forecast model of where Irma will go. This is the latest heat map from various forecast models and GFS ensemble track guidance for Irma. The GFS goes up to 10 days.

The first one I will show is for Florida. It has Irma going on the western wide of Florida. It could go over the Gulf of Mexico and west or east of Tampa Bay. Tampa Bay is one of the high risk area for storm surge due to its geography. Storm surge ravaging Tampa Bay would be worse than Katrina ravaging New Orleans and Mississippi or Sandy ravaging New York City area. You did not misread it. Tampa Bay is the worst for storm surge. Irma could go near Tampa Bay and this would be very bad.

The second one is where Irma goes once inland. There is a hot spot over Tennessee and Kentucky. This suggest that Irma may end up over that region. From there, it could east or northeast. Heavy rain will be the main problem inland depending on how fast Irma moves. The slower Irma moves, more chance for heavy rain.

Here is what I think will happen.
-Irma is going to ravage Florida.
-Storm surge and high waves will be a problem on the coast.
-Tampa Bay Area could get the brunt of Irma.

The forecast models came from NCAR-Tropical Cyclone Guidance, National Hurricane Center, , and National Weather Service. Special thanks to all of them.

Irma Getting Ever So Closer

Hurricane Irma is formidable Category 3 hurricane with 125 mph 200 km/h 109 knot winds. It has a central pressure of 933 millibars. It is moving slowly west at 9 mph. Irma should turn northward later tonight. South Florida and Florida Keys are feeling the affects of Irma.

There are feeder bands pelting South Florida with heavy rain and tropical storm force winds. Irma is a large hurricane despite weakening to Category 3.

Cuba is still experiencing hurricane force winds. Hurricane force winds are up to 138 miles 221 km 120 nautical miles across from northwest to northeast quadrant and northeast to southeast quadrant. Tropical force winds are up to 380 miles 608 km 330 nautical miles across from northwest to northeast quadrant. This makes Irma a large hurricane, which in itself is dangerous regardless of Category 3 or 5. Why large hurricanes are dangerous?

Storm surge is the problem. Larger hurricanes produce higher storm surge. Let me repeat these hurricanes that were large. Hurricane Katrina in 2005. Katrina made landfall as Category 3 on Louisiana and Mississippi. It produced storm surge as high as 35 feet/10.7 meters! By comparison, Hurricane Camille made landfall in 1969 in the same area as a Category 5 hurricane, but produced storm surge of 25 feet/7.6 meters. Camille was smaller than Katrina. Hurricane Ike is another example of a large hurricane, which made landfall on Texas as a Category 2 hurricane in 2008. Ike produce storm surge as high as 25 feet/7.6 meters, which is highest outside of Mississippi! Hurricane Sandy made landfall as a Category 1 hurricane on New Jersey in 2012. It produced storm surge as high as 15 feet/4.6 meters.

Many areas in Florida will see storm surge as high as 15 feet/4.6 meters. This type of storm surge is dangerous. The land will be inundated with 3 feet/0.9 meters or greater. That amount of water rushing in is dangerous and will wash anyone away! Anyone who lives in storm surge areas need to evacuate! If you live in an area with no storm surge, you should hide, with the exception living in a mobile home. Case in point, too many people evacuated when Hurricane Rita came barreling towards Texas and Louisiana. Most people who evacuated did not need to evacuate. This came a month after Katrina ravaged Louisiana and Mississippi. Also, more people died while evacuating than in the actual hurricane. We are seeing that problem with Florida. People who really need to evacuate are people who live in storm surge prone areas.

Here is the forecast model of where Irma will go. This is the latest heat map from various forecast models and GFS ensemble track guidance for Irma. The GFS goes up to 10 days.

Most have Irma going northwards towards Florida. It could go west of Florida or over Miami area. Either way, it is going to be bad for Florida. Once Irma is inland, most forecast models have Irma over Tennessee and Kentucky. This could be an issue as hurricanes weaken and go inland, they can dump heavy rain, especially at night. The heavy rains often fall at night near the center of the warm core low. These thunderstorms converge closer to the center at night as the low pressure system is warm core and the ambient temperature is cooler. They are called core rain. Hurricane Harvey is a tragic example of core rains that led to massive flooding in Southeast Texas including Houston. The forecast model is five days, so anything can change now and tomorrow.

Here is the most recent intensity forecast. The intensity forecast model for Irma are all over the place.

Some keep Irma as a Category 3 hurricane, while others have Irma intensifying into Category 4. I would not be surprised if Irma intensifies to Category 4 or even 5 prior to landfall on Florida. Regardless, Irma is going to be a very dangerous hurricane. A weakening hurricane can be more dangerous because people think if it weakens, than they should be safe. Hurricanes that weaken are due to land interaction or eyewall replacement cycle. Those two can cause hurricanes to get larger. Also, once eyewall replacement cycle is done, the hurricane gets larger and stronger.

The wind radii gets larger in part due to land interaction and eyewall replacement cycle as Irma gets closer to Florida. This is why I keep saying larger hurricanes are dangerous regardless of Category 3 or 5. Here is a rainfall forecast model ending at September 16, 2017 at 7:00 PM. They are from GFS, EURO, Canadian, and Weather Prediction Center (WPC).

All are in agreement that Florida will get heavy rain from Irma. GFS and WPC have the heavy rain over the middle of Florida. EURO has the heavy rain over the western part of Florida. The Canadian has heavy rain over eastern part of Florida. The GFS has the heaviest amount of up to 35.2 inches/89.4 centimeters of rain. It is south of the Florida Keys. The EURO has 17.9 inches/45.5 centimeters of rain, which is also south of the Florida Keys. Most areas should see 8 to 12 inches/20.3 to 30.5 centimeters of rain from Irma.

Here is what I think will happen.
-Irma could affect Florida as early as tomorrow morning.
-Storm surge and high waves will be a problem on the coast.
-Strong winds and heavy rain will be the main problem inland.

The forecast models came from NCAR-Tropical Cyclone Guidance, National Hurricane Center, Weather.US, Weather Prediction Center (WPC), and NWS Key West. Special thanks to all of them.

It is going to be a long night and day for Florida. Let’s hope everyone is hunkered down in areas that have no storm surge. Anyone who is storm surge prone areas are away. This could be bad for Florida.