Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 3:04 PM GMT on September 26, 2008
Tropical Storm Kyle continues chugging northwards towards Nova Scotia, Canada. Visible satellite loops show that heavy thunderstorm activity has increased some, and the Hurricane Hunters measured surface winds near 55 mph early this morning. However, Kyle is experiencing wind shear of 15-20 knots that is keeping any heavy thunderstorm activity from developing on its west side. Unless the shear relaxes, allowing Kyle's heavy thunderstorms to wrap all the way around the center, intensification into a hurricane will be difficult.
Figure 1. Current satellite image of Kyle.
Wind shear is forecast to drop slightly over the next 24 hours, to 10-20 knots. This gives Kyle a short window of time to intensify into a Category 1 hurricane. By Saturday afternoon, wind shear is forecast to increase to 25-35 knots, and the sea surface temperatures plunge from 26°C to 15°C. Kyle should weaken by 10-20 mph before landfall. The latest 06Z (2 am EDT) run of the GFDL model has Kyle hitting the Maine/New Brunswick border as a tropical storm with 60 mph winds. The HWRF has the same landfall location, but foresees only 50 mph winds. A landfall in this region as a Category 1 hurricane would likely generate a storm surge in the 3-5 foot range, according to NOAA's SLOSH model. A more easterly landfall in Nova Scotia is also a good possibility, as foreseen by some of the other reliable computer models. My best guess is a landfall in western Nova Scotia as a tropical storm with 50-60 mph winds. The west side of Kyle will remain relatively thunderstorm-free at landfall, due to strong upper-level winds from the west creating high wind shear. According to the forecast wind radius from NHC, tropical storm force winds of 39 mph and higher will miss Massachusetts, but may affect eastern Maine. Tropical storm force winds are also expected to miss Bermuda. (Use the wundermap with "wind radius" turned on to see the expected radius of tropical storm force winds).
Kyle's main threat is heavy rain. Kyle's rains will primarily affect Nova Scotia and New Brunswick at landfall on Monday morning. However, Kyle should pull copious amounts of tropical moisture and the remains of the unnamed storm that hit South Carolina last night northwards into Canada and northern New England. This will create potential serious flooding problems early next week in the region. NOAA is forecasting up to eight inches of rain could fall in New England over the next five days (Figure 2). The UKMET model is forecasting that Kyle will stall after landfall. If this forecast verifies, there is the possibility that extremely heavy rains in excess of twelve inches will fall over northern New England, New Brunswick, and Nova Scotia next week. Near-record flooding with heavy damage would likely result. However, the other models do not go along with this scenario, and rain amounts in the 6-8 inch range are more likely for northern New England, New Brunswick, and Nova Scotia.
Figure 2. Forecast rain amounts for the 5-day period ending 8 am Wednesday 10/1/08. Image credit: NOAA/HPC.
Unnamed storm hits South Carolina
The unnamed storm that moved ashore over South Carolina/North Carolina last night continues to bring heavy rain and strong winds all along the eastern U.S. The storm generated one tornado, a twister that touched down near Onslow Beach, NC at 8:15 pm EDT Thursday. No damage was reported. The storm dumped 4.16" of rain in Wilmington, NC, setting a new daily rainfall record for that city. A storm surge of four feet was observed in Carteret County, NC, and the road to the North Carolina Outer Banks was flooded by the ocean at several points during the storm. Evidence suggests the storm was probably subtropical or tropical at landfall, and could have received the name Laura. However, one of the criteria for getting a name is that a storm must persist as a subtropical or tropical storm for a "reasonable period of time". This season, it seems that NHC has been waiting longer than in the recent past (the 1990s and 2000s) to give storms names. However, in the 1970s and 1980s, a "reasonable period of time" was usually judged to be a day or longer. I doubt that yesterday's storm would have gotten a name during Nell Frank's tenure as director of NHC from 1974-1987. Thus, yesterday's decision not to name this storm is probably consistent with how things would have been done back in that era. There will always be a grey area in this regard, and NHC will inevitably get complaints about decisions to name or not name storms. If they had named this system Laura, they would have gotten complaints that are too quick to give names to storms that do not deserve them, and thus are artificially inflating tropical storm statistics to make it appear that global warming is increasing the number of tropical storms. Last night's unnamed storm fell solidly in this grey area, and there is no clear-cut "right" answer as to whether the storm deserved a name or not.
Middle Atlantic disturbance
An area of disturbed weather in the middle Atlantic, near 12N 40W, has a modest region of heavy thunderstorms. This morning's QuikSCAT pass showed an elongated surface circulation and top winds in the 20-30 mph range. Wind shear is 10-20 knots, but is expected to increase to 20-30 knots Saturday and increase further on Sunday, which should destroy the struggling circulation. NHC is giving this system a low (<20% chance) of developing into a tropical depression by Sunday.
Gulf of Mexico disturbance
An area of disturbed weather has developed in the southern Gulf of Mexico, just west of Mexico's Yucatan Peninsula. Visible satellite images show a modest but growing area of heavy thunderstorms moving east-southeast, towards the Yucatan Peninsula. Wind shear is about 15 knots over the region, which is marginal for development. The system should move ashore over the Yucatan Peninsula by Saturday before development into a tropical depression can occur. NHC is giving this system a low (<20% chance) of developing into a tropical depression by Sunday. Early next week, we will have to watch the waters on either side of the Yucatan for possible development.
The Hurricane Ike relief effort continues
Thanks to everyone who has contributed to the portlight.org charity! We raised enough money to send another truck with relief supplies to Winnie and Bridge City, Texas, where traditional relief efforts have fallen short. Wunderground member Presslord (AKA Paul Timmons, Jr.), who is coordinating this effort, has announced that if we raise an additional $10,000 mark, he will pose in a dress for our wunderphoto gallery. We're up to $2500 so far.
Figure 3. The town of Bridge City was inundated with a massive storm surge even though it was far displaced from Ike's landfall point. This speaks to just how massive Ike was. The people of Bridge City, Winnie, and other small towns in Ike's path will need help for a long time to come: www.portlight.org. Image credit: Storm Junkie.
You can read more about the effort at at stormjunkie's blog.
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