Tropical Storm Dolly to Make Landfall Late Tuesday Night in East Mexico

The fourth named storm of the Atlantic season, Dolly, closes in on the western Gulf coast of Mexico Tuesday afternoon. Climatologically the fourth named storm of the Atlantic hurricane season forms on August 23rd, so this is about a week and a half behind schedule. Moderate 10-20 kt north northwesterly shear exposed its center Tuesday morning but as of 2 pm EDT it has reformed further south closer to the deepest convection. Tropical Storm Dolly has a small window to further strengthen before the center makes landfall in Mexico late Tuesday night or early Wednesday. Hurricane Reconnaissance Aircraft and the Global Hawk investigate Dolly Tuesday afternoon and will accurately be able to access the strength and location of the storm prior to official landfall.

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Tropical Storm Dolly brings a big flooding threat to the western Gulf coast of Mexico, including the Tampico region. The mountainous terrain also enhances the threat for mudslides, especially near and south of the landfall location. 5-10″ is possible but isolated areas could receive up to 15″ of rainfall. The ECMWF estimates a bullseye of 7″+ is possible by 8 AM Friday.

ECMWF-Precip Acc

The most active month of the Atlantic season began Monday and the Caribbean and Atlantic are generally quiet. However, many reliable computer models suggest a healthy tropical wave will emerge off of Africa Thursday or Friday near the Cape Verde Islands and track westward at about 15 mph. The National Hurricane Center puts these odds at 30% over the weekend.

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The 12Z GFS suggests low pressure will bring squalls to the Cape Verde Islands Friday afternoon. This model is aggressive on tropical cyclone development and Tropical Storm Edouard could form as early as Saturday near the Cape Verde Islands. The GFS takes the tropical storm on a northwest track through the open Atlantic (well north and east of the Lesser Antilles) through mid-week next week.

GFS MSL and Precip Rate

The 12Z ECMWF doesn’t strengthen this particular tropical wave much but does develop a second stronger easterly wave on Monday or Tuesday. The graphic below is the previous model run, which also is more aggressive on development of the second tropical wave next Tuesday. Stay tuned.

ECMWF MSLP and Precip Rate

 

Tropical Storm Dolly forms in the Bay of Campeche

Late last night Tropical Storm Dolly formed as it moved into the warm waters of the Bay of Campeche.ir_enhanced_storm1 Winds are around 45mph, and while it may strengthen a little, it will likely make landfall before getting that strong. Dolly will move into mainland Mexico with no impact on the lower 48. trackmap_storm1

Elsewhere, the rest of the tropics look quiet, and cross your fingers it will stay that way.

Tropical Depression Five Forms in the Southwest Gulf

Tropical Depression Five formed in the Bay of Campeche (southwest Gulf) Monday afternoon. Enhanced satellite imagery shows and area of showers and storms on the southeast and east side of the system, although all in all the disturbance was fairly disorganized.

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As of 8pm Monday evening, TD 5 has maximum sustained winds of 30mph and a minimum central pressure of 1008mb. With the storm moving to the NW at 12mph, it is expected to be short-lived. The official track from the NHC does have it becoming Tropical Storm Dolly on Tuesday before moving into the east coast of Mexico overnight Tuesday night. Heavy rainfall is expected in eastern Mexico.

Five

 

Invest 99L Moves over the Yucatan Peninsula Late Sunday; Could Develop in Bay of Campeche Monday or Tuesday

Invest 99L has a small window of opportunity to strengthen in the western Caribbean Sunday. Convection is still disorganized early Sunday but pockets of deep convection continue in the Caribbean near the Yucatan peninsula and Belize. The NHC gives the tropical wave a 30% chance of tropical depression development before it exits warm Caribbean waters and moves over land late Sunday. By Monday the tropical wave emerges in the warm and moist Bay of Campeche. There is a 36-48 period where a brief tropical depression or Tropical Storm Dolly could spin up before it moves into mountainous east Mexico. As of Sunday morning the NHC puts these odds at a medium 50%. A Hurricane Reconnaissance Aircraft is on deck to Investigate Invest 99L in the Gulf Monday afternoon, if necessary.

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Here are the 12Z computer models. While there is some model spread a landfall in east Mexico Wednesday is a fair bet. Regardless of possible tropical cyclone development Invest 99L will enhance tropical moisture in the Gulf. Some of this could aid in heavy rainfall in northern Gulf coast states.

99l models

Not only is there deeper moisture and warmer water temperatures in the southern Gulf of Mexico/Bay of Campeche but upper levels are also more favorable in this region Monday. The 06Z GFS wind shear model paints an area of low 10 kt wind shear in the southern Gulf Wednesday afternoon.

GFS Wind Shear

A vigorous tropical wave between the Lesser Antilles and the Cape Verde Islands maintains scattered convection early Sunday. While there is dry African air north and west of this feature convection holds its own as the wave tracks west. Computer models aren’t thrilled with possible tropical cyclone development but it is still worth watching as it nears the Lesser Antilles early to mid work week. Officially the NHC is not watching this wave for further organization over the next five days. There is a fresh tropical wave off the coast of Africa southeast of the Cape Verde Islands. Convection is somewhat organized early Sunday but models like the GFS and European aren’t too impressed. These reliable models do suggest a healthy tropical wave exits Africa on Friday. This one may be worth watching.

atlantic sat

September, the busiest month of the Atlantic Hurricane season starts Monday. 34% of named storms form during the fourth month of the Atlantic hurricane season. Favorable breeding ground include the western and eastern Caribbean, much of the Atlantic, and the Gulf of Mexico.

Climatology September

Watching Invest 99L in Western Caribbean; May Move into Bay of Capeche Early Work Week

While we focus in on the east and south central Atlantic this time of year tropical development is also possible in the Caribbean and Gulf. A tropical wave (now pinned Invest 99L) has the opportunity to slowly organize. As of Saturday morning Invest 99L is situated in the western Caribbean and convection is widely scattered. Upper level winds have relaxed a bit and 10-20 kt wind shear could favor further development by Sunday. This feature moves west-northwest through the weekend and will move over land and bring squalls to the Yucatan peninsula by Sunday night. Due to proximity to land the odds of a brief tropical depression forming are only at 10% by Monday but a higher 40% over the next five days. There will be a larger window of opportunity for Invest 99L to spin up in the Bay of Campeche Monday and Tuesday before it moves into mountainous east Mexico.

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Not all computer models are on board but the ones that are suggest a west northwest track into the Bay of Campeche Monday. High pressure will guide Invest 99L towards east Mexico by Tuesday. Regardless of possible tropical depression development heavy downpours are expected for parts of Central America and east Mexico into mid work-week.

Invest 99L Models

Clearly southern Gulf of Mexico water temperatures favor tropical depression development. Buy data shows many readings in the mid to upper 80s.

Gulf of Mexico Water Temperatures

The peak of Atlantic hurricane season is less than two weeks away. 34% of named storms form during the month of September. August wraps up Sunday with likely two named storms. Hurricane Bertha formed early in the month and most recently Hurricane Cristobal passed east of the U.S.

Tropical Hurricane Frequency Graph-WTVT

The most active month of the Atlantic hurricane season is just two days away. We’re watching a few tropical waves between the Lesser Antilles and the Cape Verde Islands Saturday. The most vigorous tropical wave is just southwest of the Cape Verde Islands, but deep compact convection Saturday morning may be short lived. As of Saturday morning upper levels are favorable for deep convection and dry African air stays north of this feature. Reliable computer models like the GFS and European model are quite bullish on tropical development in the south central Atlantic through the upcoming work week. The 0Z European model keeps pressure generally low through Thursday morning.

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ECMWF MSLP and Precip Rate

Watching the Gulf and Atlantic Over Next Week

As of Thursday afternoon, Cristobal remains a hurricane, with winds of 80mph and a minimum central pressure of 973mb. The storm actually looks better now than it did for the rest of its life as a hurricane. Enhanced satellite imagery shows a fairly well-defined eye and somewhat symmetrical convective pattern. The storm will undergo extratropical transition on Friday but will still remain a dangerous storm in the coming days. Interests in Iceland should take note for Sunday and Monday.

Cristobal Enhanced Satellite

Meanwhile, we will turn our attention to a couple different disturbances in the coming days. We’ll start with the area of showers and storms currently in the western Gulf. Although it’s in an environment that’s conducive for slow development, the disturbance is running out of room. It’s expected to be over land by Friday and thus, further development is very unlikely.

Invest 98L Sat Rad

A little farther east, we have what was once designated 97L. The tropical wave located in the eastern Caribbean is currently in an environment that is not conducive for tropical development. There is plenty of dry air and wind shear is fairly high. As this wave tracks westward, wind shear is expected to remain high in its path, even through the weekend.

GFS Wind Shear

However, after this system crosses the Yucatan and re-emerges into the Bay of Campeche, the wind shear is expected to slacken. In addition, water temperatures in the area are certainly warm enough for a quick development.

Gulf of Mexico Water Temperatures

Some of our computer models try to develop something in this area later next week, though most keep the system on the weak side. We’ll certainly have to continue to watch this disturbance though, with any potential development still 5-7 days away.

ECMWF MSLP and Precip Rate

Finally, we stop our tour across the Atlantic, with a vigorous tropical wave still over the west coast of Africa expected to emerge into the open waters in the next couple days. On Wednesday several of our computer models showed development by early next week. However, by Thursday just about every model backed off. Thus, NHC gives this area 5-day odds of development of just 20%. Nonetheless, with us nearing our climatological peak of the hurricane season, we will obviously have to watch this disturbance closely over the next 7-10 days.

African Wave Enhanced Satellite

Cristobal Stays Well Offshore; Watching Multiple Tropical Waves

As of 11am Wednesday morning, Cristobal remained a hurricane, with maximum sustained winds of 80mph and a central pressure of 983mb. It remains well off the east coast, about 300 miles southeast of Cape Hatteras, and its moving to the north at 12mph. It has become slightly better organized in the last 24 hours, showing more characteristics of a hurricane (better circulation, rain bands, etc…). However, it remains fairly elongated thanks to a large amount of wind shear and some dry air. There is still a chance that Cristobal intensifies some over the next couple of days before undergoing an extratropical transition. cristobal

While Cristobal will remain at least a couple hundred miles off the eastern seaboard, it will still bring dangerous surf and rip currents to those areas through the weekend. In addition, Bermuda will likely see rainfall of 1-2″, and still could possibly see tropical storm force winds for a brief period of time courtesy of the large wind field associated with the storm.

FasTrac

Meanwhile, in the western Gulf of Mexico, an area of showers and storms looks a little better organized despite large amounts of dry air in its vicinity. This disturbance has now been designated Invest 98L. However, with the expectation that it will move onshore late Thursday into Friday, there’s only a small window for further organization. Therefore, the NHC has put the odds of tropical development at only 20% by Friday. Nonetheless, an Air Force Reconnaissance flight is scheduled to check out the disturbance Wednesday afternoon.

Floater Satellite-Radar Weekend AM

Invest 98L Models

Meanwhile, dry air and moderate wind shear are winning the battle against 97L. The disturbance, which is just east of the Lesser Antilles, looks very disorganized and lacks much deep convection. The odds of development continue to decrease, with the latest NHC update at a measly 10%. Any development of this system would be slow at best. Regardless, some storm squalls are possible in the Antilles through late work week.Carib Sat

Further east there’s an impressive tropical wave in Western Africa. The disturbance is expected to emerge off the West African coastline on Friday. Many of the reliable computer models are on board with at least some development of this system through the weekend and into early next week. However, some are more bullish than others. The European model below doesn’t show a whole lot of development by Monday morning, but still keeps pressure low into the east central Atlantic.

Africa

ECMWF MSLP and Precip Rate

However, other models, including the GFS model, suggest rapid intensification almost immediately after the wave emerges into the Atlantic. The same time frame (Monday morning) is plotted below on the GFS. Notice the difference in pressure between that model, and the aforementioned European model. We’ll have to watch this system closely in the coming days to see which model will win out. However, either way, with these Cape Verde storms, we’ll have several days (even weeks) to watch cross the Atlantic waters.

GFS Atlantic

In the seemingly ever-active eastern Pacific, we continue to watch Hurricane Marie spin off the southwest coast of Baja. The storm is much better organized than its Atlantic counterpart, though it has weakened significantly from its Category 5 peak. Winds as of 11am were 75mph with a central pressure of 980mb. While the storm will stay well of the west Mexican and US coastlines, it is still bringing some big surf to the area. Buoys just offshore of California showed wave heights up to 10 feet in areas.

Marie

East Pacific Wave Heights

 

 

Cristobal Becomes Third Hurricane of Atlantic Season; Enhances Surf at Southeast Coast Beaches

Cristobal becomes the third hurricane of the 2014 Atlantic season Monday night. Climatologically the third hurricane forms on September 9th, so this a little ahead of schedule. Despite a disorganized appearance on enhanced satellite imagery it maintains hurricane strength early Tuesday. Dry stable air north and west of Cristobal spiral around the storm and limit convection on its west side. The center is partially exposed due to strong northwesterly shear. This puts the deepest convection south and east of its center. Despite all these obstacles Hurricane Hunters continue to find hurricane force winds and as of 11 AM max sustained winds are at 75 mph. After soaking the southeast Bahamas and Turks and Caicos Sunday and Monday Cristobal lifts north away from the region Tuesday under the influence of a trough. This boundary along with another east coast trough safely guide the hurricane out to sea. Cristobal will accelerate northwest of Bermuda Wednesday. 

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Cristobal does bring some marine impacts to east Florida and the Carolinas Tuesday. Wave heights build up to 4-6 ft on Florida’s east coast. These choppy waters and a strong onshore flow enhance the threat for rip currents through mid-week. As Cristobal moves north and northeast later this work week wave heights build and rip currents are also possible up through the mid Atlantic region . A bullseye of 23 ft sits well east of the Bahamas Tuesday.FasTrac

The same trough that keeps Cristobal well east of the southeast U.S. stirs up disorganized convection in the north central Gulf of Mexico. Upper level winds are not particularly favorable for tropical cyclone development. Not to mention there is a ton of dry air east of this feature on the backside of Cristobal. Pockets of showers and storms will linger over warm northwest Gulf of Mexico waters through mid-week. There is a low 10% chance of further organization over the next five days as this energy drifts west-southwest at 10 mph.

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Futurecast shows broad low pressure will meander east of Texas Wednesday. Interest in coastal Texas and Louisiana should keep an eye on convection with Gulf water temperatures in the mid to upper 80s. By Friday this showers and thunderstorm activity should move west over the region.

Florida 12km RPM Futurecast-Weekend AM

Meanwhile in the central Atlantic Invest 97L struggles with dry air and 20-30 kt southwesterly shear. While the odds of further development are slim over the next five days if it survives the track through bone dry African air the tropical wave may be worth watching by the weekend or early next week (as the GFS model hints at). Squalls are possible in the Lesser Antilles by Friday and in Puerto Rico by Saturday. Officially per the NHC the odds of tropical depression development only sit at 20% by Sunday as it moves west-northwest at 15 mph. 

97L

Caribbean WV

Models hint that a vigorous tropical wave will move off the African coast by Friday or early this weekend. With the peak of hurricane season approaching (September 10th) it makes sense to watch the Cape Verde region closely. Stay tuned.

Tropical Storm Cristobal Forms Near the Bahamas; No Threat to U.S.

Cristobal becomes the third named storm of the 2014 Atlantic season Sunday morning. Climatologically the third named storm forms on August 13th so this is a bit later than the norm. Clearly Cristobal is much better organized compared to 24 hours ago. Constant data from Hurricane Hunters has helped computer model consensus and confidence has risen immensely that it will pass well east of Florida and the U.S.. Deep convection thrives over warm Atlantic waters. Former TD 4 exited mountainous Hispaniola late Saturday and upper level winds are also more favorable for development. Unfortunately this is right over the southeast Bahamas and Turks and Caicos. Tropical Storm Warnings are in effect for this region and 4-8″ of rainfall is possible (up to 12 inches in spots) through Tuesday. Its center reformed northeast of its original location Sunday morning but as of 11 AM it’s jogging north-northwest again at 7 mph. At this pace Cristobal will be just east of the northern Bahamas by Wednesday morning, so this will be an extended rain events for the islands. Under the influence of a trough across the east coast of the U.S. a north-northwest track becomes a much faster northeast track out to sea Thursday and Friday. Expect a higher risk for rip currents and enhanced surf at Southeast coast beaches mid to late week. The 11 AM advisory keeps Cristobal about 350 miles east of Florida.

Cristobal Sat

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Impressive rainfall totals are possible especially over the central and southeast Bahamas early this week. The European model estimates 6+” is possible in spots by Tuesday evening.

GFS-Precip Acc

Buoy data shows water temperatures in this region are in the mid 80s. With low to moderate shear in the coming days too it is realistic that Cristobal becomes a hurricane by late work week. The third hurricane of the season typically forms on September 9th.

Western Atlantic Water Temperatures

After a split in computer models early Saturday the persistent east coast trough that’s been in place this summer wins the battle. This will protect the U.S. and steer Cristobal out to sea mid work week at it rides a break in the Atlantic ridge. Under the influence of the trough Cristobal will also pick up the pace. Every single 12Z model keeps Cristobal well east of Florida and the U.S. The 06Z GFS shows the east trend and by Tuesday night (much quicker than the official forecast) the storm is just west of Bermuda.  Interest in Bermuda need to keep a close eye on Cristobal later this week.

Invest 96L Models

GFS MSL and Precip Rate

 

A Lot of Uncertainty With Invest 96L; Still A High Chance of Becoming Cristobal This Weekend

Invest 96L continues to slowly organize just north of Hispaniola and there’s still a high chance Tropical Storm Cristobal forms this weekend. There’s a lot of uncertainty in its forecast, even in the short-term. Since the disturbance is still weak in nature (just an open tropical wave) models aren’t initializing properly and there is a much greater model spread then there was just 24 hours ago. Organization over the past 12 hours has been a gradual process due to interaction with mountainous terrain and hostile upper level winds with an upper low nearby. There’s also some dry air west of Invest 96L. Hurricane Reconnaissance Aircraft investigated the disturbance Saturday morning but had no luck finding a well-defined center of circulation, therefore no Tropical Storm Cristobal just yet. Data from the mission did show pressure has dropped since Friday a sign of at least slow organization.  Invest 96L heads west-northwest towards the Bahamas through Sunday. During this time, depending on the strength of possible Tropical Storm Cristobal, we’ll have a better idea where it may head this work week. Another Hurricane Hunter mission is scheduled for Saturday afternoon. Squalls continue in Hispaniola Saturday. Heavy rain and gusty wind heads for Turks and Caicos and the Bahamas Saturday into Sunday.

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Even through the next 72 hours there is a lot of uncertainty. Below is the 12Z forecast through Tuesday morning. Models struggle with the future strength of possible Cristobal. A stronger system would head north under the influence of a trough of low pressure. A weaker system (which more models are hinting at now) would favor a further west track and miss the trough all together. The longer Invest 96L stays weak the greater chance it will take more west-northwest track.

models

Beyond Tuesday there is an even greater spread. Models are generally split between a north-northeast track out to sea and west-northwest track towards possibly Florida. Outliers suggest a track into the Gulf of Mexico is not off the table either. Clearly this is not a clear-cut forecast and trends need to be monitored closely for possible U.S. impacts this week.

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One trend the GFS suggests since Friday afternoon is a west-northwest track towards Florida. The latest 06Z run shows a weak Tropical Storm Cristobal making landfall in southeast Florida very early Wednesday. From there it basically rides Florida’s east coast towards the Carolinas bringing rain and wind to the region. Meanwhile the European model is still set on a north-northeast track out to sea but this is a little closer to the U.S. then it was just a few days ago. Stay tuned.

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