WunderBlog Archive » Category 6™
Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.Subtropical Storm Andrea not changing much
Subtropical Storm Andrea has changed little since it was named at 11am today. The amount of thunderstorm activity in the rainbands surrounding the center has decreased, and the cloud tops have warmed some, indicating weakening. However, the organization of the spiral bands of rainfall visible on the Jacksonville, FL long range radar has improved some, and winds at some of the offshore buoys have remained fairly constant the past few hours. Tropical storm-force winds cover a wide swath of ocean surrounding the center. Winds from the 6:44am EDT pass of the QuikSCAT satellite (Figure 1) were as high as 50 knots (57 mph) in the heaviest thunderstorms on the southeast side. Winds at Gray's Reef 45 miles southeast of Savannah, Georgia, have been just below tropical storm force this afternoon--33 mph, gusting to 38 mph.
Figure 1. QuikSCAT image of the surface winds at 6:44am EDT Wed May 10. Image credit: NOAA/NESDIS.
Wind shear has increased from 10 knots this morning to about 20 knots this afternoon. Shear is expected to increase to over 30 knots late tonight. Given the unfavorable wind shear, and the fact that the storm is over waters of 24-26 degrees C, I don't expect any significant intensification of Andrea. A slow decay as forecast by NHC seems reasonable.
Early storms
The last time a named storm formed so early in the year was on April 18 2003, when Tropical Storm Ana formed near Bermuda. An unnamed subtropical storm also formed on April 21, 1992.
Longest period without a tropical cyclone ends
Andrea's formation brings to a close the longest period on record globally without a tropical cyclone. The last advisory issued on a tropical cyclone this year was at 06 GMT on April 6th, for Tropical Cyclone Cliff in the Southern Hemisphere. Today's 15 GMT advisory on Subtropical Storm Andrea ends the record longest period without a tropical cyclone at 33.4 days, besting the old record of 31.5 days set mid-April to mid-May in 1984. Reliable records of global tropical cyclone numbers go back to the beginning of the satellite era, about 1970.
I'll have an update early this evening. The next Quikscat pass is at about 8pm. The next Hurricane Hunter mission is not until 8am Thursday.
Jeff Masters
Figure 1. QuikSCAT image of the surface winds at 6:44am EDT Wed May 10. Image credit: NOAA/NESDIS.
Wind shear has increased from 10 knots this morning to about 20 knots this afternoon. Shear is expected to increase to over 30 knots late tonight. Given the unfavorable wind shear, and the fact that the storm is over waters of 24-26 degrees C, I don't expect any significant intensification of Andrea. A slow decay as forecast by NHC seems reasonable.
Early storms
The last time a named storm formed so early in the year was on April 18 2003, when Tropical Storm Ana formed near Bermuda. An unnamed subtropical storm also formed on April 21, 1992.
Longest period without a tropical cyclone ends
Andrea's formation brings to a close the longest period on record globally without a tropical cyclone. The last advisory issued on a tropical cyclone this year was at 06 GMT on April 6th, for Tropical Cyclone Cliff in the Southern Hemisphere. Today's 15 GMT advisory on Subtropical Storm Andrea ends the record longest period without a tropical cyclone at 33.4 days, besting the old record of 31.5 days set mid-April to mid-May in 1984. Reliable records of global tropical cyclone numbers go back to the beginning of the satellite era, about 1970.
I'll have an update early this evening. The next Quikscat pass is at about 8pm. The next Hurricane Hunter mission is not until 8am Thursday.
Jeff Masters
Hybrid Storm Swells
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.