Tropical Storm Danny likely to be named today

By: Dr. Jeff Masters , 1:25 PM GMT on August 26, 2009

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First-light satellite images of the tropical wave (92L) a few hundred miles northeast of the Bahama Islands show that the system has developed an organized surface circulation, and 92L will likely be named Tropical Storm Danny later today. This morning's QuikSCAT pass confirms the presence of a surface circulation, and the satellite saw top winds of 50 mph in a cluster of thunderstorms well east of the center. Wind shear has dropped to the moderate range, 10 - 15 knots. The upper-level low 92L is moving underneath has plenty of dry air in it, and the upper low is injecting this dry air into 92L's west side, keeping and heavy thunderstorm activity from developing on that side. The Hurricane Hunters are in 92L, and have found surface winds up to 57 mph so far this morning. NHC continues to give 92L a high (greater than 50% chance) of developing into a tropical depression by Thursday afternoon.


Figure 1. Water vapor satellite image from 8:15 am EDT 8/26/09 showing dry air associated with an upper-level low pressure system to the west of 92L's center of circulation. Image credit: NOAA/SSD.

The forecast for 92L
As 92L continues to plow through the upper low, the low will weaken, and wind shear is expected to decline to the low range, 5 - 10 knots, by tonight. However, the upper-level low will continue to dump dry, cold air into 92L through Thursday afternoon, slowing down development. By Thursday night, when 92L should be several hundred miles off the coast of northern Florida, the upper-level low may be weak enough and far enough away that 92L will find itself in a region with light upper level anticyclonic winds, which would favor more rapid development. Most of the intensity models, including the GFDL, HWRF, and SHIPS model, forecast that 92L will become a hurricane by Friday. However, this favorable environment will not last long, since a strong trough of low pressure will be approaching the U.S. East Coast on Friday. This trough will bring high wind shear of 20 - 30 knots by Friday night. This trough should be strong enough to turn 92L to the north. The models have come into better agreement keeping 92L offshore as it passes North Carolina, though the storm is certainly capable of giving the Outer Banks a direct hit. As 92L passes North Carolina, it should start heading north-northeast, with a second landfall likely Saturday night or Sunday morning somewhere between Massachusetts and Nova Scotia. At that time, 92L is likely to be a strong tropical storm or weak Category 1 hurricane, with winds in the 55 - 80 mph range. It currently appears that 92L will not bring tropical storm-force winds to the Bahamas or to Florida.

Elsewhere in the Atlantic
The models have been inconsistently predicting formation of several tropical waves coming off the coast of Africa over the next week, and I am going to stop mentioning these forecasts until we get two models predicting the same thing, several model runs in a row.

I'll have an update later today.

Jeff Masters

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oops 70W, 25N. Got that dyslectic keyboard again.
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I would not be suprised to see that cone inch a little left throughout the day.
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patrap---lmao.
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Quoting mikatnight:


shows you how much I know...


LOL, we all learn about these things at some point, no hard feelings ;)
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Funny the difference in behaviours of the bloggers from the East Coast VS the bloggers from the GOMEX.
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I'm in the cone on Long Island - Lets wait to see the new models come up since they have a center to initiate on now
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Im in the cone =/

Might be a washout weekend and actually a windy one as well.
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Quoting TerraNova:


Huh? We just got advisories initiated, they obviously didn't wait until 2 PM...


shows you how much I know...
Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting funeeeg:
Hi All, is that another LLC at 68W 22N? You can see it on the latest visible. You can also see the main one at 35W 70N. Sorry of this has already been discussed.


Yes, I see it too. The bouys show a lower pressure @ approx 68W 22N, as opposed to where the estimated center is. The water wapor image on the NOAA site shows it quite clearly. But the pressures all around 92L are not falling much at all. Does anyone here think a new center is trying to form south of the current estimated center?
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Re: # 66


..Guess I better switch to decaff..
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Quoting VAbeachhurricanes:


im in the cone...


I'm in the cone as well..
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Quoting largeeyes:
Well, we're in the cone, but just barely.


I'm in the cone too, we have a 60% chance of heavy rain here in NE New Jersey for Friday Night/Saturday.
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Quoting TheCaneWhisperer:


Very little. It's still in the immediate area of 24.6N 70.1W from 8am.


Hehe...
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I think I might be proud of myself. The forecast I posted an hour ago is very close to what NHC is saying now. Or maybe I just have psychic powers because the storm has my name :P
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Quoting mikatnight:


10-4 big orbs, and thanks.


Huh? We just got advisories initiated, they obviously didn't wait until 2 PM...
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Well, we're in the cone, but just barely.
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NHC track out on Danny. Looks like NC and VA to take the heat on this one. I'm guessing coastal swells for SC
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Well... look at that. We have an Official Danny.
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Ex-hurricane Bill has moved across the British Isles since early this morning. The highest winds at a Met Office station were recorded in Capel Curig in Snowdownia with sustained winds of 39 mph and gusts up to 63 mph. In Bangor near the coast, where I live, the winds were quite gusty but not as strong as on higher ground. It was quite impressive though to see the rain bands coming in from the sea, the wind driving the rain drops nearly horizontally like curtains moving with the wind. The drops were quite small.
It is also surprisingly warm, a bit warmer than yesterday when it was sunny. During the last hours the winds have been dying down gradually. So that was Bill's visit to Wales in a nutshell.

Back to watching the tropics :-)
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12UTC NAM 700MB Map for Friday 18UTC (2PM EDT)

Still relatively strong ridging (318dm heights) all the way up to the coast of the Delmarva Peninsula.

There are still 2 camps in the models with a almost due north track from the GFDL/HWRF and the CMC/NAM/NOGAPS takes it over or near eastern North Carolina. Tricky forecast, but I'm starting to lean to a slightly more western track...

There is an upper level low over the Southeastern US providing a weakeness for likely TS Danny to head more toward.

Not sure Danny boy will be in a hurry to go much of anywhere until Saturday

NHC keeps it well off shore.
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Hi All, is that another LLC at 68W 22N? You can see it on the latest visible. You can also see the main one at 35W 70N. Sorry of this has already been discussed.
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NHC develops this into a minimal hurricane.

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Quoting WxLogic:


LOL... nah its moving.


Very little. It's still in the immediate area of 24.6N 70.1W from 8am.
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Needs to make that Northward turn quickly. Scary how close it is to FL.
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Link

We have TS Danny!
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622
WHXX01 KWBC 261406
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1406 UTC WED AUG 26 2009

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

DISTURBANCE DANNY (AL052009) 20090826 1200 UTC
Member Since: August 14, 2008 Posts: 0 Comments: 137


im in the cone...
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Quoting Patrap:
Latest RGB Still




Mornin' Patrap. You catch post #66? I dropped your name...BTW, could you give that link again about you helping out, meant to mark it, but forgot...
Member Since: October 18, 2005 Posts: 4 Comments: 3052
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WTNT25 KNHC 261430
TCMAT5
TROPICAL STORM DANNY FORECAST/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052009
1500 UTC WED AUG 26 2009

INTERESTS IN THE BAHAMAS AND THE SOUTHEASTERN UNITED STATES SHOULD
MONITOR THE PROGRESS OF DANNY.

TROPICAL STORM CENTER LOCATED NEAR 24.9N 70.3W AT 26/1500Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 16 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1009 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT.......120NE 0SE 0SW 120NW.
12 FT SEAS..120NE 75SE 75SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 24.9N 70.3W AT 26/1500Z
AT 26/1200Z CENTER WAS LOCATED NEAR 24.6N 70.0W

FORECAST VALID 27/0000Z 25.8N 72.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...120NE 0SE 0SW 120NW.

FORECAST VALID 27/1200Z 26.8N 73.6W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 90SE 45SW 90NW.

FORECAST VALID 28/0000Z 28.1N 74.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 30NE 0SE 0SW 0NW.
34 KT...120NE 90SE 60SW 90NW.

FORECAST VALID 28/1200Z 30.1N 75.2W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 45NE 30SE 25SW 30NW.
34 KT...135NE 100SE 75SW 100NW.

FORECAST VALID 29/1200Z 36.0N 73.5W
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 60NE 60SE 45SW 45NW.
34 KT...135NE 135SE 100SW 100NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 225 NM
ON DAY 4 AND 300 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 30/1200Z 45.0N 67.0W...EXTRATROPICAL
MAX WIND 65 KT...GUSTS 80 KT.

OUTLOOK VALID 31/1200Z 52.0N 53.0W...EXTRATROPICAL
MAX WIND 60 KT...GUSTS 75 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.9N 70.3W

NEXT ADVISORY AT 26/2100Z

$$
FORECASTER BEVEN

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000
WTNT25 KNHC 261430
TCMAT5
TROPICAL STORM DANNY FORECAST/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052009
1500 UTC WED AUG 26 2009

INTERESTS IN THE BAHAMAS AND THE SOUTHEASTERN UNITED STATES SHOULD
MONITOR THE PROGRESS OF DANNY.

TROPICAL STORM CENTER LOCATED NEAR 24.9N 70.3W AT 26/1500Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 16 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1009 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT.......120NE 0SE 0SW 120NW.
12 FT SEAS..120NE 75SE 75SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 24.9N 70.3W AT 26/1500Z
AT 26/1200Z CENTER WAS LOCATED NEAR 24.6N 70.0W

FORECAST VALID 27/0000Z 25.8N 72.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...120NE 0SE 0SW 120NW.

FORECAST VALID 27/1200Z 26.8N 73.6W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 90SE 45SW 90NW.

FORECAST VALID 28/0000Z 28.1N 74.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 30NE 0SE 0SW 0NW.
34 KT...120NE 90SE 60SW 90NW.

FORECAST VALID 28/1200Z 30.1N 75.2W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 45NE 30SE 25SW 30NW.
34 KT...135NE 100SE 75SW 100NW.

FORECAST VALID 29/1200Z 36.0N 73.5W
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 60NE 60SE 45SW 45NW.
34 KT...135NE 135SE 100SW 100NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 225 NM
ON DAY 4 AND 300 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 30/1200Z 45.0N 67.0W...EXTRATROPICAL
MAX WIND 65 KT...GUSTS 80 KT.

OUTLOOK VALID 31/1200Z 52.0N 53.0W...EXTRATROPICAL
MAX WIND 60 KT...GUSTS 75 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.9N 70.3W

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Really looking forward to seeing the NHC track on this.
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Atlantic - Caribbean Sea - Gulf of Mexico
Tropical Weather Outlook (en EspaƱol*)
800 AM EDT WED AUG 26 2009 Tropical Weather Discussion
805 AM EDT WED AUG 26 2009

Tropical Storm DANNY Storm Archive
Public
Advisory
none issued
in last 12 hrs Aviso
Publico
none issued
in last 12 hrs Forecast/
Advisory
#1
1500 UTC Forecast
Discussion
none issued
in last 12 hrs Wind Speed
Probabilities
none issued
in last 12 hrs



ITS OFFICIAL!!!!Link
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Quoting tornadofan:


nrtiwlnvragn - you make this blog enjoyable. Thanks for posting this stuff.


Thanks. Just a weather geek like others.
Member Since: September 23, 2005 Posts: 14 Comments: 11071
I highly doubt the NHC is gonna name it without a vortex message
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Current 12Z Steering currents (Bermuda High) has been restrengthening for the last 6HR... of course once 92L has gain some depth, then we should start seeing a more N component to the motion:

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Guess I need to call home and check on the fire ants.
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Latest RGB Still


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Quoting TheCaneWhisperer:


Looks almost stationary or committing NW.


LOL... nah its moving.
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Quoting VAbeachhurricanes:


storms trying to wrap around the north side of the circulation


I see that. Finally getting a little winds on the west side.
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SFWMD says Danny...
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Quoting largeeyes:
Scheduled at 2, they'll break into regularly scheduled programming if a TC has formed.


10-4 big orbs, and thanks.
Member Since: October 18, 2005 Posts: 4 Comments: 3052
re:104

thats highly probable with Danny. Might be more east or west of that but its a possiblity. dont think the intensity will be that strong but who knows with a hot gulf stream
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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