Tropical Storm Danny not impressive yet
Tropical Storm Danny is here, born from an African tropical wave that developed a closed circulation and some respectable heavy thunderstorm activity this morning. Data between 2 - 3 pm EDT from the Hurricane Hunters indicates the Danny has a central pressure of 1009 mb, and top surface winds of about 45 mph. Satellite imagery shows that Danny's circulation has gotten stretched and pulled away from the heaviest thunderstorm activity on the storm's east side. It is possible that Danny's center will reform at a different location, closer to the heaviest thunderstorms, so the model forecasts probably have a higher degree of uncertainty than usual at present. Wind shear has dropped to the low range, 5 - 10 knots. The upper-level low Danny is moving underneath has plenty of dry air in it, and this dry air is intruding into Danny's west side, keeping and heavy thunderstorm activity from developing on that side.
Figure 1. Oceanic heat content for August 25, 2009. Regions where the Sea Surface Temperature is below 80°F, or where the shallow waters of the Continental Shelf lie, do not have enough heat content to be plotted, and are shown in white colors. The oceanic heat content along the track of Tropical Storm Danny is below the threshold of 90 kJ/cm^2 typically seen with cases of rapid intensification. The storm position at 8am EDT today is given by the hurricane symbol with the "0" inside it. Subsequent hurricane symbols show the official NHC forecast points from the 11 am EDT forecast today, for 8am Thursday (24 hours), 8am Friday (48 hours), 8am Saturday (72 hours), and 8am Sunday (72 hours). The cold waters stirred up by Hurricane Bill last week will not impact Tropical Storm Danny. Image credit: RSMAS, University of Miami.
The forecast for Danny
As Danny continues to plow through the upper low, the low will weaken, but will dump dry air into the storm through Thursday afternoon, slowing down development. By Thursday night, when Danny should be several hundred miles off the coast of northern Florida, the upper-level low may be weak enough and far enough away that Danny will find itself in a region with light upper level anticyclonic winds, which would favor more rapid development. Ocean heat content (Figure 1) is high enough to support a hurricane, until Danny gets to about New Jersey's latitude. Most of the intensity models, including the GFDL, HWRF, and SHIPS model, forecast that Danny 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 Danny to the north, then northeast on Saturday. The models have come into better agreement keeping Danny offshore as it passes North Carolina, though the storm is certainly capable of giving the Outer Banks a direct hit. As Danny passes North Carolina, it should start heading north-northeast, with a landfall likely Saturday afternoon or evening somewhere between Massachusetts and Nova Scotia. At that time, Danny is likely to be a strong tropical storm or weak Category 1 hurricane, with winds in the 55 - 80 mph range. The latest runs of the GFDL and GFS model have Danny tracking directly over Martha's Vineyard, where President Obama is on vacation. It will be interesting to see if the president stays on the island for Danny.
For those of you wondering about specific probabilities of getting tropical storm force or hurricane force winds, consult the NHC Wind Probability Product.
Figure 2. Tropical wave newly emerged from the coast of Africa, with some potential for development.
Elsewhere in the Atlantic
A well-organized tropical wave has exited the coast of Africa, and lies a few hundred miles southeast of the Cape Verdes Islands. None of the models are gung-ho about developing this wave, but shear is low, 10 knots, and waters are warm enough to support development. The dry Saharan Air Layer is relatively limited in extent and intensity, so dry air may have only a small inhibiting effect on the wave. Expect some slow development of this wave as it moves westward over the next few days. NHC is giving this system a low (less than 30% chance) of developing into a tropical depression by Friday afternoon.
I'll have an update Thursday.
Jeff Masters
Reader Comments
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Something still has to form in the right spot to affect us even if the pattern is conducive.
Guess that Danny will have some effect on the Kennedy funeral on Saturday. Just wondering if the wind will be a major factor on the turnout?
Sorry, I was just going by what stormW said and forecast models are indicating plus it was the same thing that happened 2004.
Hell, Conch, so am I...and so we wait. What're Kelly's plans?
94L
we had 93l already
and yea
I know.. I just didn't like 2004/2005 all that much as far as Hurricane's go. I liked 1992 a lot less though.
I was hoping the NE would be the only target this year - not that I want ANYONE to be targeted.
I don't want to bait them my way either though!
Practice, baby, practice...how are you Tig?
Just now checking in...
Things seem to be picking back up in the tropics. I see we now have Danny and maybe a soon to be that came off Africa??
Very understandable we took it on the chin in Ivan and Katrina here in Mobile.
We need to watch this one =)
Bill got closer to the US than originally expected, don't rely on the models so early in the game. Pay attention to the cone, not the dotted lines.
Could/Would Danny move more west if he fails to develope or loses some strength?
As in usually the desire to follow troughs and weaknesses in the BH are from developed systems with the weaker ones moving west.
Looks pretty organized, we might see an 'orange' by tonight or tomorrow. Will be interesting what the quickscat has to say.
This could be the next major with the way things look down the path, but we'll just have to wait and see
Don't get all funkadelic on him, but I do understand your point. My house hasn't been fixed completely from Wilma yet either! Still remodeling and in fact this weekend another floor goes down.
WTNT01 KNGU 262101Z
SUBJ: TROPICAL STORM DANNY (05L) WARNING NR 002
1. TROPICAL STORM DANNY (05L) WARNING NR 002
01 ACTIVE TROPICAL CYCLONE IN ATLANTIC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
261800Z --- NEAR 25.0N 70.8W
MOVEMENT PAST SIX HOURS - 300 DEGREES AT 10 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
000 NM SOUTHEAST QUADRANT
000 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
REPEAT POSIT: 25.0N 70.8W
---
FORECASTS:
12 HRS, VALID AT:
270600Z --- 26.0N 72.5W
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
000 NM SOUTHEAST QUADRANT
000 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 315 DEG/ 08 KTS
---
24 HRS, VALID AT:
271800Z --- 27.1N 73.8W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 340 DEG/ 09 KTS
---
36 HRS, VALID AT:
280600Z --- 28.7N 74.5W
MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
000 NM SOUTHEAST QUADRANT
000 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
120 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 360 DEG/ 12 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
281800Z --- 31.1N 74.5W
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 020 DEG/ 19 KTS
---
72 HRS, VALID AT:
291800Z --- 38.5N 71.5W
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 030 DEG/ 27 KTS
---
LONG RANGE 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.
---
96 HRS, VALID AT:
301800Z --- 47.5N 63.5W
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
EXTRATROPICAL
VECTOR TO 120 HR POSIT: 055 DEG/ 28 KTS
---
120 HRS, VALID AT:
311800Z --- 53.1N 48.0W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
EXTRATROPICAL
---
REMARKS:
262100Z POSITION NEAR 25.2N 71.2W.OR APPROX 639NM
SSE OF CAPE HATTERAS, NORTH CAROLINA.
12FT SEAS: 150NM NE, 75NM SE, 75NM SW, 150NM NW.
NEXT WARNINGS AT 270301Z, 270901Z, 271501Z AND 272101Z.//
BT
#0001
NNNN
261806Z AUG 09
FM NMFC
BT
UNCLAS
MSGID/NMFC/OVLY2/0238/AUG
OVLY/ATL STORM 05L/261800Z7/AUG/1OF1/TROP STORM DANNY(05L)/METOC
TEXT/12//G/250000N7/0704800W9/S
TEXT/12//G/270600N5/0734800W2/S
TEXT/12//G/310600N0/0743000W4/S
TEXT/12//G/383000N4/0713000W1/H
TEXT/12//G/473000N4/0633000W2/S
TEXT/12//G/530600N4/0480000W2/S
LINE/6//G/250000N7/0704800W9/270600N5/0734800W2/310600N0/0743000W4
/383000N4/0713000W1/473000N4/0633000W2/530600N4/0480000W2
ARC/0/G///250000N7/0704800W9/150NM/150NM
ARC/0/G///270600N5/0734800W2/150NM/150NM
ARC/0/G///310600N0/0743000W4/150NM/150NM
ARC/0/G///383000N4/0713000W1/150NM/150NM
TEXT/12//G/230000N5/0681800W3/TROP STORM DANNY
TEXT/12//G/220000N4/0681800W3/26 AUG 1800Z
TEXT/12//G/210000N3/0681800W3/MAX 40 KT
TEXT/12//G/200000N2/0681800W3/300 AT 10 KT
TEXT/12//G/190000N0/0681800W3/34 KT RADII SHOWN
TEXT/12//G/270600N5/0694800W7/2718Z MAX 45
TEXT/12//G/310600N0/0703000W0/2818Z MAX 60
TEXT/12//G/383000N4/0673000W6/2918Z MAX 65
TEXT/12//G/473000N4/0593000W7/3018Z MAX 60
TEXT/12//G/530600N4/0440000W8/3118Z MAX 45
ENDAT
BT
#0001
NNNN
0509082312 140N 480W 20
0509082318 146N 500W 20
0509082400 152N 520W 20
0509082406 159N 540W 20
0509082412 165N 560W 20
0509082418 171N 580W 20
0509082500 184N 599W 20
0509082506 202N 616W 25
0509082512 217N 633W 25
0509082518 228N 650W 25
0509082600 233N 667W 40
0509082606 238N 685W 40
0509082612 246N 700W 40
0509082618 250N 708W 40
Nice structure.
Yes, but its still all east of the LLC.
I'm not sure about the Quickscat. The steering for the next 7 days or so continues to feature a trough over the eastern portion of the CONUS; thereafter, while some of the ensemble members keep a flatter trough over the eastern seaboard, the ensemble consensus favors a ridge over the eastern seaboard. This is certainly not set it stone and is subject to change.
Looks like NC will be spared again. Could still be a threat to New England and Canada. Odds are starting to look like the US EC will dodge another bullet. The LLC looks to be relocating further E= track shifts east.
Last I checked New England is still part of the East Coast of the United States. Well when I went to bed last night it was anyway. Someone needs to tell me what country I live in now so, I can update my passport.
Gabrielle?
Yep if has a Close low this will be likely 94L by tommorow.
FIU will let anyone in. I'm only kidding. FAU represent..lol
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