Right on cue for late July/early August we’re watching a tropical wave near Africa. The is the first healthy Cape Verde wave of the season. There’s plenty of time to keep an eye on this feature but it is an early reminder that Cape Verde season is just about here. During August and September tropical waves organize near the Cape Verde Islands and have the opportunity to become some of the strongest hurricanes of the season if moisture stays plentiful and wind shear stays low. Invest 96L is worth watching as it moves westward. The broad area of low pressure emerging off of Africa has a medium chance of tropical depression development over the next 5 days.
While dry air still rules much of the Atlantic and Caribbean Invest 96L may stand a chance to organize. It is south of some of the deepest dry Saharan air (indicated by yellow, orange and red) and at a favorable latitude for at least gradual organization. Wind shear in the vicinity is also low to moderate. The graphic below is courtesy NOAA/the University of Wisconsin.
Wednesday afternoon computer models suggest a westward track over the next few days and west northwest track by late weekend. Some early intensity models suggest a tropical storm is possible in a couple of days over the open central Atlantic. Both the Euro and GFS suggest this wave may not survive the long term forecast. We’ll keep a close eye.
Tropical Storm Darby brings squalls to Hawaii Sunday and more heavy rain is on the way. Direct hits are rare for Hawaii. Darby is the first named storm to make landfall since Iselle in 2014. Ironically both landfalls were within 15 miles of each other on the Big Island. The storm recharges Sunday after being disrupted by high volcanoes. As of 5 AM EDT Darby is a minimal tropical storm with 40 mph winds. The center is south of Maui Sunday morning. A west-northwest track will continue through Monday. This puts Maui, Oahu and Kauai on the wetter, east side of the storm. Rainfall also continues on the Big Island. Some areas could easily pick up 8-12 inches of rainfall, with locally higher amounts. Tropical storm wind gusts are also likely along with swells and rough surf. Conditions gradually improve by late Monday as it weakens, eventually dissipates and heads out to sea.
Dry African air remains entrenched in the Atlantic as indicated by the orange shade in the Caribbean on water vapor imagery. Climatology favors a more active August as Cape Verde season begins. If just a few healthy tropical waves roll off of Africa and moisten the central Atlantic (main development region) a pattern change is likely. The GFS has toyed with this possibility by early August but the Euro is not on board.
The active July in the east Pacific continues Saturday. So far this month there are 7 named storms (this ties a record with 1985). As of Saturday morning Tropical Storm Frank and Georgette are no threat to land, but Tropical Storm Darby closes in on the Big Island of a Hawaii where a Tropical Storm Warning is in effect. As of 11 AM EDT max sustained winds are at 50 mph as the storm heads west at 9 mph. Tropical storm force winds are just offshore but squalls are expected by Saturday afternoon. Darby will be distrupted by high terrain/volcanoes on the Big Island and will weaken some before making it Maui Saturday night and Oahu Sunday. The storm could bring 10-15″ inches of rainfall to some spots this weekend.
Surf is also enhanced near the island state. Wave heights build to near 15 feet just east of the Big Island Saturday morning.
As busy as it is in the east Pacific there are no areas of interest in the Atlantic Basin. Dry African air has ruled the Gulf, Caribbean and Atlantic this July and more of the same continues this weekend. The graphic below shows the extent of the Saharan Air Layer via NOAA/the University of Wisconsin as indicated by shades of yellow, orange and red.
Due to this dry air tropical waves have stood no chance. The long-range GFS suggests the Cape Verde season tries to come alive in late July and early August. Below is a closed area of low pressure on Monday August 1st between the Cape Verde Islands and Africa. The reliable Euro is not board. The odds of tropical cyclone development increase from just 8% in July to 27% in August. With plenty of warm water to fuel strong named storms once enough tropical waves moisten the main development region in the Atlantic August could be a very active month.
An active Saharan Air Layer has kept activity limited in the Atlantic Basin this month and the trend continues Saturday. Notice a huge blast of dry air in mid levels on the atmosphere in the eastern Caribbean with more extensive dry air across the central Atlantic too. There are no areas of interest and no tropical depression development is expected for the next 5 days and beyond. Long-range models hint the Atlantic may moisten some with a few more tropical waves by the end of the month. There is a still a decent chance that July will wind down with no named storms.
July is typically a quiet month in the tropics. Only 34 named storms have formed from July 11-20th in the Gulf, Caribbean and Atlantic since 1851. Origin points are in line with climatology in July with development in the Gulf, western Atlantic, western or eastern Caribbean. The graphic below is courtesy Google earth.
While there have been 4 named storms in the Atlantic there are now 5 named storms in the east Pacific so far in 2016. Estelle became the 5th named storm this season (and the 5th named storm this month) late Friday and is on track to become the 4th hurricane of 2016 in the east Pacific basin by Monday. All of the storms have taken a similar track and dissipated over the open Pacific. There is a chance moisture from Darby could pass near the Big Island of Hawaii by Friday or Saturday. By then, Darby may barely be a tropical storm. Elsewhere broad low pressure may develop by early work week south of Mexico. There is a low chance of tropical depression development by mid-week.
It’s been two and half weeks since Danielle, the most recent named storm in 2016, dissipated over east Mexico. Since then there have been no areas of interest and officially per the NHC no tropical depression development is expected over the next 5 days. For most the week the European model hints that low pressure may deepen off the Mid-Atlantic region mid-week. There is the potential for this low to have some tropical characteristics before it heads out to sea (no threat to land). The latest 0Z Saturday Euro backs off on low pressure development east of the Carolinas mid to late work week. We’ll keep an eye on new model runs.
On Saturday there are two named storms in the east Pacific. Blas is downgraded to a tropical storm and will steadily weaken over cooler waters. On it’s heels is Tropical Storm Celia. Celia could become the 3rd hurricane of the east Pacific season by Sunday. Both storms are no threat to land but the remnants of Blas could enhance rainfall in Hawaii late next week.
Former Super Typhoon Nepartak makes landfall as a minimal tropical storm over Southeast China. Moisture will bring heavy rain to this region over the next few days. The European model estimates over 5″ is possible by Monday evening (US EDT). Parts of China are still recovering from recent heavy rainfall and any additional rain will aid in more flooding.
The first week of July is off to a quiet start in the Atlantic Basin. This is often the case early in the second month of hurricane season. Dry dusty African air covers much of the Caribbean and Atlantic which limits the amount of tropical waves in the region. This is indicated by the red color on water vapor imagery shown below.A tropical wave in the eastern Caribbean is tangled in dry air aloft. There is also moderate southwesterly shear with a mid and upper low nearby. None of our reliable computer models hint at any areas of tropical cyclone development for at least the next 5 days. The long-range Euro suggests we need to keep an eye on the western Atlantic near the Carolinas in about 7-10 days, but that’s a ways off.
Meanwhile, the east Pacific is quite active. The second named storm of 2016, Blas, is now the first major hurricane of the season. It may strengthen to category 4 strength before gradually weakening mid-week. Hurricane Blas is headed away from Mexico over the open Pacific. Right behind Blas is Invest 96L. It is likely to become a tropical depression by the end of the week. It is no threat to Mexico as it is headed westward.
While the 2016 Atlantic season is at a stand still with no tropical cyclone development on the horizon for a while the east Pacific heats up. It’s official. Agatha becomes the first named storm of the 2016 east Pacific season Saturday. The east Pacific hurricane season began on May 15th. Agatha is the second latest first named storm to form in the east Pacific Basin. According to Phil Klotzbach of Colorado State University the earliest first named storm in the east Pacific formed on July 3rd, 1969. Agatha is headed out to sea and will gradually weaken early next week. On it’s heels is Invest 94E. While it is likely to develop into a tropical depression this weekend the future tropical cyclone is no threat to Mexico as it is headed for the open Pacific.
This may be the start of a series of storms forming in the east Pacific. Here is the 0Z Euro next Sunday afternoon.
The second month of the 2016 Atlantic hurricane season begins Friday. There are no areas of interest and no tropical cyclone development is expected for at least the next 7 days. Only 8% of named storms typically form in July. Early July is often especially quiet. Only 35 named storms have formed from July 1-10 since 1851. The graphic below is courtesy Google Earth. Notice most origin points are in the Gulf, western Atlantic or eastern Caribbean. These are common breeding grounds for named storms in July.
Dr. Kllotzbach and scientists at Colorado State University issued an update to their 2016 Atlantic season forecast Friday. They forecast 15 named storms, 6 hurricanes and 2 major hurricanes. This includes the 4 named storms including 1 hurricane we’ve already seen. Therefore, they expect an additional 11 named storms, 5 hurricanes and 2 major hurricanes. In an average Atlantic season there are 12 named storms, 6 hurricanes and 3 major hurricanes so they anticipate an above average number of named storms but an average number of hurricanes. La Niña is possible during the peak of season later this summer which could mean lower wind shear in the main development region and enhanced tropical cyclone development. At the same time water temperatures in the north Atlantic could be running below average which could hinder development some.
High pressure have a firm grip on the Atlantic Basin. There are a few tropical waves in the eastern Caribbean and south central Atlantic but none are particularly organized. Dry dusty air from Africa covers the Atlantic and keeps Caribbean tropical waves limited too. An upper trough in the northern Gulf enhances convection over the northern Gulf waters. This feature will dissipate over the next 24 hours.
Meanwhile the east Pacific is heating up. There are still no named storms in the east Pacific basin in 2016. That may change over the next 5 days. Invest 94E south of Mexico has a high chance of becoming a tropical depression by early next week (indicated by the red polygon). Another area of low pressure well south of the Baja peninsula has a medium chance of tropical depression developing in the coming days.
The tranquil spell continues in the Atlantic Basin with no tropical cyclones on the horizon for least the next week. A very weak area of low pressure develops near a stalled front east of Florida but this boundary should dissipate over the next 24 hours. Overall, dry air and moderate wind shear keep convection limited in the Gulf, Caribbean and western Atlantic. While there are already 4 named storms in the Atlantic in 2016 the east Pacific is off to a slow start. So far there are no named storms. By late June typically there are already 2 named storms, one of which reaches hurricane strength. A tropical wave over Central America has a low chance of tropical depression development as in emerges in the east Pacific in the coming days.
As we approach the beginning of the July the breeding grounds for tropical development shift some. In July storms tend to ride the Atlantic Bermuda High and can track northwest into the western Atlantic or westward through the Caribbean and up into the Gulf of Mexico. Keep in mind only 8% of named storms form during the entire month of July. The season sees peak activity in August and September when the Cape Verde season gets going.
Long-range computer models really don’t show much happening as we head into the first week of July. Here’s the Euro next Wednesday July 3rd. Notice a low deepening west of Mexico in the east Pacific a perhaps weak low pressure along a front east of the U.S..
Invest 95L has looked less impressive over the past 24 hours. Convection is disorganized and the weakening area of low pressure will move inland over east Mexico early Saturday. While it will bring pockets of heavy rainfall to the region (as did Danielle) a tropical depression is highly unlikely. The odds of development are bumped down to 0% per the NHC.
None of the reliable computer models develop anything in the Atlantic Basin over the next 7 days. Even the GFS has backed off on possible low pressure in the Gulf around the 4th July (good news of course). Below is the forecast 7 days from now on Friday July 1st. With the exception of moisture in the western Caribbean there are no areas of note. While 2016 already has 4 named storms in the Atlantic it not uncommon to see a tranquil spell in late June and early July. On average only 6% of named storms form in June. That percentage only climbs to 8% in July.