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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sorry for the multiple posts all. cell-phone posting does not agree with WU blogs...
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For those who missed this earlier:


PRESS RELEASE: July 1, 2009

ECSC: A RIDE OF HISTORIC PROPORTIONS


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-----------------------------------------------------------
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Held annually in Virginia Beach, Virginia since 1963, ECSC is more than just surfing. Dozens of people also take part in other competitions including skimboarding, volleyball, an oceanfront 5K run, a swimsuit competition and the extreme sport of skateboarding. Live bands perform for free on an oceanfront stage throughout the weekend.
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12Z
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Wow. Battle of wits between the regular operational GFS and the ensemble mean. Come on ensemble. Go. Go. Go. That would be very nice.

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Tracks should definately come left
Does anyone have a latest imagery off the Afrocan coast??
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Member Since: October 18, 2005 Posts: 4 Comments: 3052
For the GOM discussion, it is not the usual afternoon storms. It is associated with a front.
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You don't think that if a Hurricane was going to hit the NE they would still have a funeral?

Talk about setting people up for trouble.
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week #2
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Westward
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704. IKE
You can see the ULL over LA./Mississippi...
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Yellow circle on interest off African coast now...
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Quoting largeeyes:
What would that formation of dropsondes be called?


AOML calls it "Drop Plan"
Member Since: September 23, 2005 Posts: 14 Comments: 10835

it support development of 94L and danny
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Quoting atmoaggie:

Your posts are showing just fine. Maybe you have yourself on ignore?
i'm posting from my cell phone, and everytime i reloaded the page, it reposted it. sorry. :/
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Quoting nrtiwlnvragn:


I would think due to the upper level low spinning over LA. Measure the upper level winds which should be NE due to the low.
Quoting nrtiwlnvragn:


I would think due to the upper level low spinning over LA. Measure the upper level winds which should be NE due to the low.


thanks for the info.
Member Since: August 18, 2009 Posts: 0 Comments: 157
Quoting Seastep:


Yes! Thanks! Will check it out. Appreciated.

No prob. Happened to see that the URL is getting mangled by the blog here, you might need to copy and paste it. I have it set up just fine in the post...

Addendum: I think jeffs kids have joined us...or something.
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What would that formation of dropsondes be called?
Member Since: August 22, 2006 Posts: 0 Comments: 1451
Quoting Dakster:
NRAamy - tell me your not 4'10" tall...

NRT - The dropsonde pattern looks like a tractor...


Don't tell Aubie
Member Since: September 23, 2005 Posts: 14 Comments: 10835
Quoting largeeyes:
Gonna be a massive funeral in Boston on Saturday. THAT should be interesting.


Good point. Didn't think of that.
Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting obsessedwweather:
In the GOM....off the west coast of Florida really starting to flare up storms, which are typical. Will be interesting to keep watching though.

Also keeping an eye on the wave off of Africa.


Our local weather guy in Tallahassee at Noon (on WCTV) said that according to some of the local computer models, there is a hint that a Surface Low may try to form today or tomorrow in the NE Gulf of Mexico.

Pretty much all it would do is enhance our rain chances on Thursday and Friday in Tallahassee but something to keep an eye on I guess. Looking at the Long Range radar from Tallahassee, there is some slight spinning going on but nothing very strong.
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Quoting atmoaggie:
Is SeaStep here? Was asking about the SFMR and shallow water last night.

The SFMR is known to have a high bias when the water depth is less than 30 M and to have a low bias with very high rain rates. They are both correctable...I think (maybe just the rain fall-effected data)...but aren't as of yet. Always tweaking the obs...

A good paper detailing it: www.nhc.noaa.gov/jht/05-07reports/JHT07_Carswell_midyear.pdf

Neither of these has to do with water in the air but with the effect of both circumstances on foaming on the water surface.


Yes! Thanks! Will check it out. Appreciated.
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Danny's low may just decouple from the system and run into Florida with the rest of the heavy rain moving up the coast.
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NRAamy - tell me your not 4'10" tall...

NRT - The dropsonde pattern looks like a tractor...
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Quoting jeffs713:
lol! baby got back?

Your posts are showing just fine. Maybe you have yourself on ignore?
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Quoting justalurker:


question, why the GOM?


I would think due to the upper level low spinning over LA. Measure the upper level winds which should be NE due to the low.
Member Since: September 23, 2005 Posts: 14 Comments: 10835
test
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Gonna be a massive funeral in Boston on Saturday. THAT should be interesting.
Member Since: August 22, 2006 Posts: 0 Comments: 1451
.
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Quoting NRAamy:
It wasn't me. I've had 10-4-2 as my numbers since late June.

I've had 36 - 24 - 36 since I was 18....how do I rank?


That was good! I wonder how many minds are in the gutter after that one and just won't admit it LOL! So much for a slow season with those numbers!

I still say we could get an active season with the peak still over 2 weeks away and then lets not forget that other little peak in the beginning of October. The GOM waters stay warm for a long time after the air tempertures in the fall start to cool!
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677. 900MB
Getting a little convection to the north of coc.


Does seem to be going more west than anything right now, or is it just me?
Member Since: June 11, 2006 Posts: 0 Comments: 660
675. IKE
Looks to me like dry-air is getting into Danny....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting nrtiwlnvragn:
The key near term model run will be this evenings 00Z. The Gulfstream IV will be releasing dropsondes in this pattern this afternoon.





Latest Recon Plan of the Day

000
NOUS42 KNHC 261745
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NTIONAL HURRICANE CENTER, MIAMI, FL.
0145 PM EDT WED 26 AUGUST 2009
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 27/1100Z TO 28/1100Z AUGUST 2009
TCPOD NUMBER.....09-090

I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM DANNY
FLIGHT ONE - TEAL 70
A. 27/1800Z
B. AFXXX 0505A DANNY
C. 27/1430Z
D. 27.4N 74.1W
E. 27/1700Z TO 27/2130Z
F. SFC TO 10,000 FT

FLIGHT TWO - NOAA 49
A. 28/0000Z
B. NOAA9 0605A DANNY
C. 27/1730Z
D. NA
E. NA
F. 41,000 TO 45,000 FT

FLIGHT THREE - TEAL 71
A. 28/0600Z
B. AFXXX 0704A CYCLONE
C. 28/0230Z
D. 29.1N 74.8W
E. 28/0500Z TO 28/0930Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: 6-HRLY FIXES
BEGINNING AT 28/1800Z.

3. REMARKS: NOAA WILL CONTINUE FLYING RESEARCH MISSIONS
EVER 12 HRS ON DANNY THROUGH 28/0800Z.



question, why the GOM?
Member Since: August 18, 2009 Posts: 0 Comments: 157
I liked the picture of herself she used as her avatar a couple of years ago.

yeah, now I'm incognito...

;)
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now the "west wishcasters" has something to talk about again
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is that a pertabation in the itcz at 40w. this area should be watched for any signs of cyclogenesis
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"Could they at least use a stencil of some sort to make the circle round. It looks like shakes the clown drew it."

Based on the avitar I think nramy draws those circles.
Is SeaStep here? Was asking about the SFMR and shallow water last night.

The SFMR is known to have a high bias when the water depth is less than 30 M and to have a low bias with very high rain rates. They are both correctable...I think (maybe just the rain fall-effected data)...but aren't as of yet. Always tweaking the obs...

A good paper detailing it: www.nhc.noaa.gov/jht/05-07reports/JHT07_Carswell_midyear.pdf

Neither of these has to do with water in the air but with the effect of both circumstances on foaming on the water surface.
Member Since: Posts: Comments:

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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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