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Category: Tropical

Alex Becomes Hurricane

| 9:07 am January 14, 2016

Alex continues to make meteorological news in the Atlantic. And the latest is that Alex has become a hurricane. The Azores Meteorological Service has issued a Hurricane Warning for the islands of Faial, Pico, Sao Jorge, Graciosa, and Terceira in the central Azores, and a Tropical Storm Warning for the islands of Sao Miguel and Santa Maria in the eastern Azores.

As you can see from the visible satellite presentation below, Alex presents very well in this view from space.

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The NHC forecast track for Alex remains on a northerly course. Alex should remain a hurricane through Friday morning before transitioning back to a sub tropical storm.

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Chalk that up as one hurricane already for the 2016 hurricane season in the Atlantic – and hurricane season does not officially start for another four and a half months!

-Brian-

The 2015 North Atlantic Hurricane Season

| 8:17 am December 2, 2015

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The 2015 North Atlantic Hurricane Season was fairly slow, as had been predicted in most seasonal forecasts. There were eleven named storms, which is very close to the long term average of 11.5. Four of the storms became hurricanes and two went on to become major hurricanes, below the long term averages of 6.1 hurricanes and 2.6 major hurricanes.

The season got started well before the official start date of June 1st, when Tropical Storm Ana formed from a non-tropical low on May 8th. The system had peak winds of 60 mph as it crossed over the Gulf Stream. It would weaken as it moved off the Gulf Stream and go on to make landfall on the northeastern coast of South Carolina with winds of 45 mph.

A named storm forms in the Atlantic in June in just about every other year on average, and Bill did just that, jumping straight to tropical storm status on the first advisory based on aircraft reconnaissance data. The storm was designated Bill on the evening of June 15th with a well defined circulation center some 175 miles east southeast of Corpus Christi, Texas. It made landfall later on the 16th on Matagorda Island, with a central pressure of 997 mb and top winds of 60 mph.

The storm remained unusually organized as it made the trek northward across Texas and into Oklahoma, perhaps aided by the “brown island effect” of saturated ground from recent heavy rain over the southern Plains. Newport, Oklahoma picked up a two day rain total of 11.52 inches. I-35 was closed in the Arbuckle Mountains due to a rock slide.

A tropical depression formed about 250 miles east northeast of Cape Hatteras on July 16th. SIx hours later it was upgraded to Tropical Storm Claudette. The storm weakened as it moved northeastward and merged with a frontal boundary, but it still produced adverse weather in Newfoundland, where flights were canceled.

Danny was a Cape Verde storm that became the season’s first major hurricane with top winds of 115 mph. Danny would weaken due to dry air and wind shear and dissipated before reaching the Leeward Islands.

Tropical Storm Erika was another Cape Verde storm like Danny, but never got its act together. The storm formed on August 25th and steamed across the Atlantic, making landfall on Dominica and in Hispaniola. The storm dissipated while dodging Cuba, but brought heavy rains to South Florida.

Hurricane Fred formed from a very strong tropical wave that moved off Africa on August 29th, became a depression on the 30th and quickly became a hurricane on the 31st. It is the furthest east that a hurricane has ever formed in the Atlantic and prompted hurricane warnings for the Cape Verde Islands for the first time in history.

The season entered a boring period, with unremarkable tropical storms named Grace, Henri and Ida forming over the open Atlantic and dissipating before affecting any land areas.

Hurricane Joaquin stole the show during the 2015 Atlantic Hurricane Season. Joaquin formed east of the Bahamas on September 28th and became a tropical storm on the following day as it moved in a southwesterly direction toward the Bahamas. It would continue to strengthen and became a major hurricane on the evening of the 30th. Hurricane Joaquin would affect the Bahamas as a category four hurricane, but would weaken as it moved through the islands. Joaquin turned to the northeast and very nearly achieved category five status when its top winds reached 155 mph. It was the most intense Atlantic hurricane since Igor in 2010. Fortunately, Joaquin weakened before it impacted Bermuda with heavy rain and tropical storm force winds.

The official National Hurricane Center forecasts predicted for three days that Joaquin could impact the eastern United States, despite strong indications from the European model that the storm would remain well offshore. This led to considerable angst along the East Coast and a look at how the National Hurricane Center’s Cone of Uncertainty is used in such situations.

Part of the moisture pulled northward by Joaquin would be pulled back into South Carolina by a big upper level low, which resulted in catastrophic flooding in the Palmetto State.

The final named storm was Kate, which became a hurricane on November 11th, making it the latest hurricane since Epsilon in 2005. Kate affected the southeastern Bahamas, but recurved off the East Coast of the U.S. and missing Bermuda.

While the storm counts were slightly below the long term averages, the energy expended by the eleven storms was just 59 percent of normal. The Atlantic basin was dominated by El Nino conditions during the hurricane season. The higher than normal wind shear contributed to the below normal activity.

For the tenth straight year, there has been no landfall of a major hurricane in the United States. It hasn’t happened since Hurricane Wilma in October 2005. In addition, Florida has not bit hit by ANY hurricane of any intensity since Wilma.

Kate Arrives ! !

| 7:31 am November 9, 2015

Kate has arrived. The National Hurricane Center (NHC) has issued an advisory at 7:20 am CST as Tropical Depression 12 strengthened enough to become a tropical storm. That advisory is shown below. As we note, the Hurricane Hunter aircraft data were instrumental in providing the information to forecasters. The depression strengthened pretty much as expected and the future track for Kate will take it through the Bahamas and recurving before reaching Florida. After that Kate becomes a nuisance mainly for shipping as the track is expected to take it north of Bermuda. Bet they have some pretty good swells/waves on the island, though.

-Brian-

WTNT62 KNHC 091319
TCUAT2

TROPICAL STORM KATE TROPICAL CYCLONE UPDATE
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122015
820 AM EST MON NOV 09 2015

...DEPRESSION STRENGTHENS TO A TROPICAL STORM...

Air Force Reserve hurricane hunter aircraft data indicate that
Tropical Depression Twelve has strengthened to Tropical Storm Kate.
The maximum sustained winds are estimated to be 40 mph (65 km/h)
with higher gusts.

SUMMARY OF 820 AM EST...1320 UTC...INFORMATION
----------------------------------------------
LOCATION...24.2N 74.9W
ABOUT 40 MI...60 KM ESE OF CAT ISLAND IN THE BAHAMAS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES

$$
Forecaster Cangialosi/Stewart 

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Could We Have Kate Tomorrow?

| 8:18 pm November 8, 2015

The National Hurricane Center (NHC) is watching an area of showers and thunderstorms associated with a small low pressure area located just east of the southern Bahama Islands. This area has shown some signs of becoming better organized since this morning, and forecasters have pegged the chance of formation through the next 48 hours at 80 percent. According to the Tropical Weather Outlook from NHC, it will not take much more organization for it to become a tropical depression or perhaps a tropical storm. Should it gain enough strength to become a storm, it would be given the name Kate.

No matter what happens to it, heavy rainfall and gusty wind can be expected over portions of the Bahamas. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate the system on Monday morning. The various computer model guidance, second graphic below, shows the disturbance is likely to move northwestward for the next day or so before beginning to recurve away from the US coast and out into the Atlantic where it would be a problem for shipping interests as well as the folks in Bermuda.

-Brian-

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* * * U P D A T E * * *
At 9:00 pm CST, the National Hurricane Center issued an advisory on Tropical Depression 12. Thunderstorm activity has increased over the eastern portion of the circulation which has been enough to classify the system as a depression. A Hurricane Hunter aircraft will investigate the storm Monday morning providing NHC with much better information on the cyclone’s intensity. Initial NHC forecasts indicate that the system is likely to become a tropical storm in the next 24 hours.

Another Tropical Cyclone Aiming for Yemen

| 4:48 pm November 8, 2015

Yemen is a popular spot for tropical cyclones this time of year – well, at least this year. The second tropical cyclone in about a week is taking aim at Yemen. After forming in the Arabian Sea, Cyclone Megh has been tracking on a westerly course. It passed over the Socotra Archipelago yesterday and was moving by the northeast tip of Somalia this afternoon. The latest satellite view along with the past and forecast tracks are in the graphic below. Megh was a category 2 storm, however, it is forecast to dissipate over the next couple of days becoming a depression before making landfall on the western end of Yemen. At least there is some consolation that Megh is not following along the exact path taken by Chapala last week. Megh is not making the kind of headlines Chapala did simply because it is not as strong as Chapala was. Megh will bring more rain to Yemen whose annual rainfall is less than 5 inches according to what I’ve read.

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-Brian-

48-Hour Rainfall Ending Nov. 2

| 8:06 am November 3, 2015

The National Weather Service (NWS) office in Birmingham tweeted this graphic which quite nicely shows the rain that has fallen over Alabama during the last several days.

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The graphic illustrates two important items. First, ALL of the state of Alabama has had rain – some more than others. Looks like the northwest corner was a little short changed in the amount of rain they recorded.

Second, this really illustrates how narrow the bands of highest rainfall can be. Note in the map that there is a band of 3 to 4 inch rain running from eastern Bibb County northeastward to the northeast corner of Calhoun County. That band does not appear to be more 5 to 6 miles wide. A second and heavier band of rain shows up in the Florida Panhandle and stretches across portions of Southeast Alabama. The band starts as fairly broad, but splits into two heavy bands with more than 4 inches across Southeast Alabama. Each of those prongs is very narrow, maybe 10 to 12 miles. I think this clearly illustrates how difficult it is to forecast the exact location of heavy rain – or heavy snow.

Special thanks to the folks at the NWS in Birmingham for creating and sharing the graphic.

And for those who may have been following the record setting typhoon on the other side of the world, Chapala came ashore overnight on the coast of Yemen. Chapala is forecast to diminish fairly rapidly over the next 12 to 18 hours, but it will bring record rain to the western half of Yemen.

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-Brian-

Chapala Churning Closer to Land

| 8:17 am November 2, 2015

Typhoon Chapala remained a hurricane this morning and continued to churn across the Arabian Sea and the Gulf of Aden as it gets closer to landfall in Yemen.

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This is the latest satellite view of Chapala. It was getting closer to Yemen after brushing just north of the island of Socotra in the Arabian Sea. The Joint Typhoon Warning Center (JTWC) placed Chapala’s wind at 105 knots this morning with gusts to 130 knots (120 mph with gusts to 150 mph). The forecasters there continued to predict a gradual weakening trend as Chapala makes its was toward landfall just to the west of Mukalla (or Al Mukalla on some maps) around midnight tonight. Once the eye has made landfall, the tropical cyclone should diminish in strength rapidly falling below tropical storm strength about 24 hours after landfall. Here’s the graphic from JTWC.

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Here’s another view of Cyclone Chapala.

tccapture

-Brian-

Tropical Troubles in Arabian Sea

| 10:15 am October 31, 2015

I know that it is one the other side of the world, but while the Atlantic and Eastern Pacific basins were quiet, Tropical Cyclone Chapala was taking advantage of the warmest waters ever recorded in the Arabian Sea for this time of year to rapidly intensify overnight. Chapala topped out for the time being as a high-end Category 4 storm with 155 mph wind early Friday morning, according to the Joint Typhoon Warning Center (JTWC). The India Meteorology Department (IMD), responsible for tropical cyclone warnings in the North Indian Ocean, placed Chapala’s intensity at 130 mph winds with a central pressure of 942 mb on Friday morning. This made Chapala the second strongest tropical cyclone on record in the Arabian Sea right behind Category 5 Cylcone Gonu of 2007, the only Category 5 storm ever recorded in the Arabian Sea. The North Indian Ocean as a whole has seen five Category 5 storms in recorded history ; four of them occurred in the Bay of Bengal, so Chapala becomes the sixth strongest tropical cyclone ever observed in the North Indian Ocean.

Chapala.A2015303.0910.1kmImage: Tropical Cyclone Chapala as seen by the MODIS instrument at 0910 UTC October 30, 2015. At the time, Chapala was at peak strength with 155 mph winds. Image credit: NASA.

According to NOAA’s Historical Hurricanes tool, there have only been six major Category 3 or stronger tropical cyclones recorded in the Arabian Sea. The period of record, though, is somewhat short as accurate satellite records only go back to 1990. The Arabian Sea doesn’t see many tropical cyclones since it is small; furthermore, the Southwest Monsoon keeps the tropical cyclone season short with a season that lasts from May to early June before the monsoon arrives. Another short season occurs from late October through November after the monsoon has departed. Strong Arabian Sea storms are rare due to high wind shear and a generous supply of dry air from the deserts of the Middle East.

Recent satellite images showed that Chapala degraded slightly in organization Friday, and JTWC reduced the storm’s estimated intensity to 140 mph winds as of 12Z Saturday. The storm was still in a low wind shear environment with warm ocean water near 30°C or 86°F so Chapala is likely to remain a strong hurricane with landfall on Monday morning in a sparsely populated area in Yemen just west of the border with Oman as it begins to weaken.

The latest forecasts take Chapala into the east coast of Yemen as a Category 1 hurricane and into Saudi Arabia as a weakening tropical storm. Apart from any wind damage, this course will bring huge downpours to eastern Yemen and western Oman where almost any amount of rainfall is an event worth noting. Local rainfall totals from Chapala could easily exceed 10 inches

-Brian-

This information was gained from a number of sources including the Joint Typhoon Warning Center, Weather Underground, and USA Today.

Patricia Strongest Hurricane Ever in Western Hemisphere

| 11:37 am October 23, 2015

patricia fri 1630z avn-animated

Hurricane Patricia in the eastern Pacific underwent an incredible rapid intensification yesterday and overnight and aircraft reconnaissance found 175 knot winds (200 mph) just before 2 a.m. this morning. The central pressure was estimated at 880 millibars. I say estimated, because the dropsonde instrument used to record pressure, wind, temperature and other parameters did not splash down in the true center of the hurricane. The instrument recorded 885 mb and the crew estimated that the minimum pressure was 880 mb.

The winds make Patricia the strongest hurricane ever observed in the western hemisphere. Patricia is stronger than Wilma from 2005, which had the distinction of having the lowest central pressure observed in the Atlantic (882 millibars). And the top winds of 175 knots are certainly the strongest observed in any tropical cyclone around the world since 1970. Wind speeds were probably routinely overestimated prior to 1970. Patricia is stronger than Haiyan, which has 170 mph winds in the northwestern Pacific and Allen, which had 165 knot winds in 1980 in the North Atlantic.

Typhoon Tip still holds the distinction of having the minimum central pressure observed around the globe, with 870 millibars measured by reconnaissance on October 12, 1979. But Tip’s winds were 165 knots, short of Patricia’s record this morning.

Water temperatures underneath Patricia are running 30C, which is about 1 degree C warmer than they have been ever observed in the past 34 years. Cloud tops around the center have warmed a bit in the past couple of hours, perhaps indicating some weakening, but catastrophic conditions will occur along the coast near and east of where the center makes landfall. Fortunately, there are no major population centers in the swath where the maximum effects are expected to occur.

Landfall will come early this evening on the Mexican coast west of Manzanillo in the state of Jalisco. This is southeast of Puerto Vallarta, where they will experience tropical storm force winds in just a couple of hours and strong tropical force winds by 7-8 p.m. tonight. Hurricane conditions may remain just east of Puerto Vallarta.

It will turn to the north northeast over the mountainous terrain of Mexico. It should weaken to tropical storm force by tomorrow afternoon and become a remnant low by Sunday. It will bring torrential rains to Mexico and South Texas even as it weakens. The remnant low will get revitalize over Coastal Texas over the weekend and could bring heavy rain to southern and eastern Texas, as well as southern Louisiana. The WPC is calling for widespread 3-8 inch amounts from the eastern half of Texas all the way into Arkansas and western Mississippi and western Tennessee.

As the low moves slowly northeast, it may bring a nice rain event to Alabama by next Tuesday with an inch of rain possible.

Joaquin Passing NW of Bermuda

| 8:10 pm October 4, 2015

It’s been a cloudy, rainy, and rather blustery day for the people in Bermuda. Hurricane Joaquin, though diminishing some in strength, has been traveling northward just to the west of Bermuda. It appears from the Bermuda Weather Service radar that the center of Joaquin passed just west of the island nation with the eastern edge of the eye wall only 80 kilometers west of the radar site. The latest radar image is shown below and indicated that Joaquin was west-northwest of the island and moving away.

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According to weather observations taken at the L. F. Wade International Airport, the highest sustained wind was from the south at 46 mph with a gust to 64 mph. The barometric pressure was reported to be at 29.25 inches which is the lowest value reported so far today.

I’m afraid all this interest in the hurricane focused on Bermuda has piqued my travel interests to visit that island – after they recover.

-Brian-