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Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.TD Karl Headed Towards Bermuda; Record Rains in Norfolk From Julia's Remnants
A Tropical Storm Watch is up for the island of Bermuda, as Tropical Depression Karl steams northwest towards the island at 17 mph. Karl continues to remain disorganized due to moderate wind shear of 15 knots, but the shear is forecast to fall to the low range, 5 - 10 knots, on Friday. This may allow Karl to strengthen enough to spread tropical storm-force winds to Bermuda before the storm turns to the northeast and moves away from the island on Saturday.
In the eastern Atlantic, there is not much new to say about Tropical Storm Lisa. Lisa is headed to the northwest into an area of high wind shear and dry air, which should be able to destroy this unimpressive 50-mph tropical storm by Sunday.
Figure 1. Latest satellite image of Karl.
Two Atlantic threat areas to watch next week
A medium-sized tropical wave that emerged from the coast of Africa on Thursday morning had a modest amount of heavy thunderstorm activity, but not very much spin. This wave is too close to the equator (near 8°N) to be able to leverage the Earth’s spin and acquire enough spin of its own to develop into a tropical depression, and is not likely to develop through this weekend as it heads west to west-northwest at 15 - 20 mph across the tropical Atlantic. However, the tropical wave may move far enough from the equator to be able to develop by early next week, when it reaches a point about halfway between the Lesser Antilles Islands and the coast of Africa. About 30% of the 20 forecasts from the members of the 00Z Thursday GFS ensemble showed this wave developing between Monday and Wednesday, and about 10% of the 50 members of the European model ensemble did so. This system is likely to move through the Lesser Antilles Islands as early as Wednesday or as late as Friday of next week.
A cold front will move into Texas on Monday, and potentially stall offshore of Texas on Tuesday. A tropical depression could spin up along the tail end of this cold front over the Bay of Campeche, a few hundred miles south-southeast of the Texas/Mexico border, by the middle of next week. However, fewer than 10% of the members of the 00Z Thursday GFS and European model ensemble forecasts showed this occurring.
Invest 94E off the Pacific coast of Mexico may develop
In the Eastern Pacific, satellite loops on Thursday morning showed that an area of low pressure about 850 miles south of the southern tip of the Baja California Peninsula (Invest 94E) was increasing in organization and heavy thunderstorm activity, and this storm has the potential to develop into tropical depression this weekend. Our top three models for predicting hurricane genesis—the GFS, UKMET and European models—predicted in their 00Z Thursday runs that 94E would develop into a tropical storm or tropical depression, but that this storm would stay well offshore of Mexico’s Baja Peninsula though the next five days. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 70% and 90%, respectively.
Figure 2. Precipitation analyzed for the 7-day period ending at 12Z (8:00 am EDT) Thursday, September 22, 2016. Widespread 10-15” totals have occurred over southeast VA and northeast NC since Monday in association with the remnants of Tropical Storm Julia. Image credit: NOAA/NWS Advanced Hydrologic Prediction Service.
Julia’s remnants feed massive rains across Hampton Roads area
A slow-moving slug of atmospheric moisture associated with former Tropical Storm Julia took up residence this week across the Mid-Atlantic. Together with a lingering front, the moisture has fueled several days of heavy rainfall in southeast Virginia and northeast North Carolina. Preliminary rainfall totals for the period from Sunday through Wednesday night included 13.73” near the Kempsville area of Virginia Beach, VA. By and large, the rains have been prolonged but not extremely intense, producing mainly widespread road closures.
The hardest-hit metropolitan area is Hampton Roads, VA, including Norfolk and Portsmouth. In the 72 hours ending at midnight Wednesday night, Norfolk International Airport picked up 9.35” of rain. That includes three consecutive days of daily-record precipitation: 3.04” on Monday, 2.38” on Tuesday, and 3.93” on Wednesday. As noted by Capital Weather Gang, this is the only instance of three consecutive daily precipitation records in Norfolk data going back to 1874, according to local weathercaster Tim Pandajis. The city’s wettest September--13.80”--occurred in 1979, when Norfolk experienced deluges from Hurricane David as well as a tropical depression later that month. As of this morning, Norfolk’s total for this September was up to around 13”. With showers still in the area today, the September 1979 record is in striking distance.
Jeff Masters and Bob Henson
In the eastern Atlantic, there is not much new to say about Tropical Storm Lisa. Lisa is headed to the northwest into an area of high wind shear and dry air, which should be able to destroy this unimpressive 50-mph tropical storm by Sunday.
Figure 1. Latest satellite image of Karl.
Two Atlantic threat areas to watch next week
A medium-sized tropical wave that emerged from the coast of Africa on Thursday morning had a modest amount of heavy thunderstorm activity, but not very much spin. This wave is too close to the equator (near 8°N) to be able to leverage the Earth’s spin and acquire enough spin of its own to develop into a tropical depression, and is not likely to develop through this weekend as it heads west to west-northwest at 15 - 20 mph across the tropical Atlantic. However, the tropical wave may move far enough from the equator to be able to develop by early next week, when it reaches a point about halfway between the Lesser Antilles Islands and the coast of Africa. About 30% of the 20 forecasts from the members of the 00Z Thursday GFS ensemble showed this wave developing between Monday and Wednesday, and about 10% of the 50 members of the European model ensemble did so. This system is likely to move through the Lesser Antilles Islands as early as Wednesday or as late as Friday of next week.
A cold front will move into Texas on Monday, and potentially stall offshore of Texas on Tuesday. A tropical depression could spin up along the tail end of this cold front over the Bay of Campeche, a few hundred miles south-southeast of the Texas/Mexico border, by the middle of next week. However, fewer than 10% of the members of the 00Z Thursday GFS and European model ensemble forecasts showed this occurring.
Invest 94E off the Pacific coast of Mexico may develop
In the Eastern Pacific, satellite loops on Thursday morning showed that an area of low pressure about 850 miles south of the southern tip of the Baja California Peninsula (Invest 94E) was increasing in organization and heavy thunderstorm activity, and this storm has the potential to develop into tropical depression this weekend. Our top three models for predicting hurricane genesis—the GFS, UKMET and European models—predicted in their 00Z Thursday runs that 94E would develop into a tropical storm or tropical depression, but that this storm would stay well offshore of Mexico’s Baja Peninsula though the next five days. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 70% and 90%, respectively.
Figure 2. Precipitation analyzed for the 7-day period ending at 12Z (8:00 am EDT) Thursday, September 22, 2016. Widespread 10-15” totals have occurred over southeast VA and northeast NC since Monday in association with the remnants of Tropical Storm Julia. Image credit: NOAA/NWS Advanced Hydrologic Prediction Service.
Julia’s remnants feed massive rains across Hampton Roads area
A slow-moving slug of atmospheric moisture associated with former Tropical Storm Julia took up residence this week across the Mid-Atlantic. Together with a lingering front, the moisture has fueled several days of heavy rainfall in southeast Virginia and northeast North Carolina. Preliminary rainfall totals for the period from Sunday through Wednesday night included 13.73” near the Kempsville area of Virginia Beach, VA. By and large, the rains have been prolonged but not extremely intense, producing mainly widespread road closures.
The hardest-hit metropolitan area is Hampton Roads, VA, including Norfolk and Portsmouth. In the 72 hours ending at midnight Wednesday night, Norfolk International Airport picked up 9.35” of rain. That includes three consecutive days of daily-record precipitation: 3.04” on Monday, 2.38” on Tuesday, and 3.93” on Wednesday. As noted by Capital Weather Gang, this is the only instance of three consecutive daily precipitation records in Norfolk data going back to 1874, according to local weathercaster Tim Pandajis. The city’s wettest September--13.80”--occurred in 1979, when Norfolk experienced deluges from Hurricane David as well as a tropical depression later that month. As of this morning, Norfolk’s total for this September was up to around 13”. With showers still in the area today, the September 1979 record is in striking distance.
Jeff Masters and Bob Henson
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.