Dr. Jeff Masters' WunderBlog

Danny still weak

Posted by: Dr. Jeff Masters, 07:32 PM GMT on Αύγουστος 28, 2009

Tropical Storm Danny continues to look unhealthy, with an exposed low-level center and the main heavy thunderstorms well to the east. The center is oval instead of circular, which may portend that this center will dissipate and a new center will form under the heaviest thunderstorm activity. Danny has more of the appearance of a subtropical storm than a tropical storm on satellite imagery, and this structure will slow down any potential intensification. The amount of heavy thunderstorm activity has increased in the past few hours, though no thunderstorms have formed near the center. The latest Hurricane Hunter mission found one small spot of 45 mph surface winds between 1 - 3 pm EDT today, so Danny may barely qualify as a tropical storm. Danny's center may have begun moving to the north over the past hour, giving confidence that the storm's strongest winds and rain will stay offshore of North Carolina tonight and Saturday morning.

Figure 1. Afternoon satellite image at 3:03 pm EDT of Danny, showing the exposed swirl of clouds where Danny's center is, well displaced from the heaviest thunderstorm activity to the east. The center is oval-shaped and not circular, the sign of a weak circulation.

The forecast for Danny
With wind shear at 15 knots this afternoon, and forecast to increase to 20 knots tonight and 30 knots Saturday morning, it is unlikely Danny will be able to strengthen to more than a 50 mph tropical storm. Dry air from the upper-level low that has been keeping Danny disorganized continues to be a problem for the storm, as well. Most of the intensity forecast models continue to insist Danny will strengthen, but they have been doing a very poor job forecasting the intensity of Danny. With Danny's heavy thunderstorms all on the east side of the storm, it is unlikely that North Carolina or New England will feel tropical storm force winds from Danny when it scoots past on Saturday. Large swells from Danny creating high surf along the beaches of New England will be the primary hazard from the storm.

Massachusetts hurricane history
Two tropical storms have affected Massachusetts in the past decade, though neither of these storms brought sustained winds of tropical storm force (39 mph) to the state. Tropical Storm Beryl of 2006 just missed Cape Cod as a weak tropical storm with 45 mph winds. Beryl brought wind gusts to tropical storm force to Nantucket Island, and a 1 foot storm surge. Tropical Storm Hermine hit southeast Massachusetts on August 31, 2004, as a minimum-strength tropical storm with 40 mph winds. No land stations in Massachusetts reported tropical storm force winds during Beryl. The last time Massachusetts measured tropical storm force winds was in 1997 during that year's version of Tropical Storm Danny. Chatham recorded sustained winds of 44 mph, and Nantucket had 43 mph winds. The last time Massachusetts had hurricane force winds was in 1991 during Hurricane Bob, which hit Rhode Island as a Category 2 hurricane. Provincetown, Massachusetts measured sustained winds of 98 mph, gusting to 115 mph, and Buzzard's Bay received a 15 foot storm surge.

Invest 94L
The well-organized tropical wave (94L) mid-way between Africa and the Lesser Antilles Islands continues to be a threat to develop into a tropical depression in the next day or two. Water vapor satellite loops show that 94L has moistened the region surrounding it considerably today, and the storm is not ingesting as much dry air as this morning. However, visible satellite loops show only a small amount of heavy thunderstorm activity near the circulation center, which is broad and elongated from east to west. Shear is low, about 10 knots, and is expected to remain low, 5 - 10 knots, over the next five days. The waters are warm enough to support development, 27°C, and are expected to remain in the 27 - 28°C range over the next five days. It appears that 94L needs another 1 - 3 days to develop a well-formed circulation and become a tropical depression, given the favorable environment. NHC is giving 94L a medium (30 - 50% chance) of developing into a tropical depression by Sunday. Most of the models predict 94L will Be affected by two troughs of low pressure over the next week, which will pull the storm far enough north so that it will miss the Lesser Antilles Islands. It is then probable that 94L will be forced to the west again as the high pressure ridge steering the storm builds back in. The possible long-term threat to the U.S. East Coast is impossible to evaluate at this time.

I'm in New York City this weekend for my cousin's wedding, so will not be blogging again until Monday morning. In my absence, wundergound's severe storms expert, Dr. Rob Carver, will be posting in my blog Saturday and Sunday.

Jeff Masters

Categories: Hurricane

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1051. IKE 08:51 AM GMT on Αύγουστος 29, 2009
RIP Danny! Bye-bye Danny....what a waste of a name... TROPICAL DEPRESSION DANNY DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052009 500 AM EDT SAT AUG 29 2009 SATELLITE IMAGES...SURFACE OBSERVATIONS AND DATA FROM AN AIR FORCE RECONNAISSANCE PLANE INDICATE THAT DANNY IS RAPIDLY BECOMING ABSORBED BY A FRONTAL LOW WHICH IS DEVELOPING OVER NORTH CAROLINA. IN FACT...THE PLANE TRAVERSED THE POSSIBLE LOCATION OF DANNY A COUPLE TIMES AND DID NOT FIND ANY SIGNIFICANT CYCLONIC WIND SHIFT NOR DID IT MEASURE TROPICAL STORM FORCE WINDS AT THE SURFACE. THEREFORE...ADVISORIES ON DANNY HAVE BEEN TERMINATED AND THE TROPICAL STORM WATCH HAS BEEN DISCONTINUED. THE EXTRATROPICAL LOW WILL MOVE TOWARD THE NORTH-NORTHEAST AND THEN NORTHEAST AND ITS POTENTIAL IMPACTS WILL BE HANDLED WITH GALE WARNINGS AND OTHER PRODUCTS ISSUED BY LOCAL NWS OFFICES IN THAT REGION. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 34.3N 74.6W 30 KT...BECOMING ABSORBED 12HR VT 29/1800Z 38.0N 73.0W 35 KT...EXTRATROPICAL 24HR VT 30/0600Z 41.2N 69.2W 40 KT...EXTRATROPICAL 36HR VT 30/1800Z 46.2N 62.8W 40 KT...EXTRATROPICAL 48HR VT 31/0600Z 49.5N 56.0W 40 KT...EXTRATROPICAL 72HR VT 01/0600Z 54.5N 43.5W 40 KT...EXTRATROPICAL 96HR VT 02/0600Z 56.5N 27.0W 45 KT...EXTRATROPICAL 120HR VT 03/0600Z 57.0N 10.1W 50 KT...EXTRATROPICAL $$ FORECASTER AVILA Member Since: Ιούνιος 9, 2005 Posts: 23 Comments: 37044

1052. KoritheMan 09:02 AM GMT on Αύγουστος 29, 2009
Quoting IKE: Tropical Depression DANNY ...DANNY RAPIDLY BECOMING ABSORBED BY AN EXTRATROPICAL LOW... 5:00 AM EDT Sat Aug 29 Location: 34.3�N 74.6�W Max sustained: 35 mph Moving: NNE at 30 mph Min pressure: 1007 mb When one dies, another is born: ...TENTH TROPICAL STORM OF THE 2009 EAST PACIFIC SEASON FORMS SOUTH OF MEXICO... Member Since: Μάρτιος 7, 2007 Posts: 410 Comments: 15450

1053. IKE 09:07 AM GMT on Αύγουστος 29, 2009
And still no model runs since 6Z yesterday from GFDL and HWRF on 94L. From looking at it, RIP is becoming more likely with it too..... Member Since: Ιούνιος 9, 2005 Posts: 23 Comments: 37044

1054. ackee 09:14 AM GMT on Αύγουστος 29, 2009
just seem like 94L going to despiate Member Since: Ιούλιος 15, 2008 Posts: 0 Comments: 1194

1055. bcn 09:25 AM GMT on Αύγουστος 29, 2009
Nothing anywhere in next 15 days, probably season is ended. Member Since: Αύγουστος 20, 2008 Posts: 0 Comments: 62

1056. markymark1973 09:30 AM GMT on Αύγουστος 29, 2009
Goodbye 94L. Easterlies are tearing everything up and winning the battle this year. Bill actually was an impressive system from the get go and just got lucky. Unless there is a big pattern change for September the tropics will be dead. El Nino years are so boring:(

1057. markymark1973 09:33 AM GMT on Αύγουστος 29, 2009
Quoting bcn: Nothing anywhere in next 15 days, probably season is ended. That is VERY possible.

1058. IKE 09:45 AM GMT on Αύγουστος 29, 2009
00Z ECMWF....South America view, shows a couple of lows coming off Africa. First one dies out as it moves west through the EATL. Second one affects the Cape Verdes. Shows nothing for the Caribbean islands west through the USA through September 8th. Member Since: Ιούνιος 9, 2005 Posts: 23 Comments: 37044

1059. HadesGodWyvern 09:46 AM GMT on Αύγουστος 29, 2009
National Hurricane Center Tropical Cyclone Advisory #2 TROPICAL CYCLONE JIMENA (EP132009) 9:00 AM UTC August 29 2009 ============================= At 6:00 AM UTC, Tropical Storm Jimena (1006 hPa) located at 14.1N 102.3W or 220 southwest of Acapulco, Mexico has sustained winds of 35 knots with gusts of 45 knots. The cyclone is reported as moving west at 10 knots. Forecast and Intensity ===================== 12 HRS: 14.4N 103.5W - 40 kts (Tropical Storm) 24 HRS: 14.9N 104.8W - 50 kts (Tropical Storm) 48 HRS: 16.4N 107.3W - 75 kts (SSHS-1 Cyclone) 72 HRS: 19.5N 110.0W - 80 kts (SSHS-1 Cyclone) Member Since: Μάιος 24, 2006 Posts: 43 Comments: 36687

1060. HadesGodWyvern 09:46 AM GMT on Αύγουστος 29, 2009
Central Pacific Hurricane Center Tropical Cyclone Advisory #2 TROPICAL DEPRESSION CP022009 9:00 AM UTC August 29 2009 ============================= At 6:00 AM UTC, Tropical Depression Two-C (1007 hPa) located at 15.0N 178.1W or 510 west of Johnston Island has sustained winds of 30 knots with a gust of 40 knots. The depression is reported as moving west at 6 knots. Forecast and Intensity ====================== 24 HRS: 15.4N 179.1E - 35 kts (Tropical Storm) Member Since: Μάιος 24, 2006 Posts: 43 Comments: 36687

1061. HadesGodWyvern 09:49 AM GMT on Αύγουστος 29, 2009
Japan Meteorological Agency Tropical Cyclone Advisory #10 TROPICAL STORM KROVAHN (T0911) 18:00 PM JST August 29 2009 ========================================= Subject: Category One Typhoon Near Ogasawara Shoto At 9:00 AM UTC, Tropical Storm Krovahn (994 hPa) located at 27.9N 146.6E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The storm is reported as moving north-northwest at 13 knots. RSMC Dvorak Intensity: Gale-Force Winds ================ 180 NM from the center in eastern quadrant 90 NM from the center in western quadrant Forecast and Intensity ====================== 24 HRS: 32.0N 141.1E - 55 knots (CAT 2/Severe Tropical Storm) 45 HRS: 36.2N 141.2E - 55 knots (CAT 2/Severe Tropical Storm) 69 HRS: 42.4N 148.0E - 45 knots (CAT 1/Tropical Storm) Member Since: Μάιος 24, 2006 Posts: 43 Comments: 36687

1062. IKE 09:54 AM GMT on Αύγουστος 29, 2009
NEW BLOG!!!!!!!!!!! Member Since: Ιούνιος 9, 2005 Posts: 23 Comments: 37044

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