Tropical Depression Two forms from Invest 98L

By: Dr. Jeff Masters , 9:33 PM GMT on July 17, 2011

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Tropical Depression Two (TD2) formed from Invest 98L this afternoon. Hurricane Hunters flew into the suspect area and found a surface circulation north of the Bahamas, with maximum sustained winds of 35 mph. They also determined the system had become warm core—a characteristic that must be present in order to declare a tropical cyclone. Satellite imagery continues to show the system is becoming more organized with a stronger circulation. Wind shear is forecast to remain favorable for the system until Tuesday or Wednesday when higher shear will slide in from the north. Sea surface temperatures are warm enough to sustain a tropical storm.


Figure 1. Satellite imagery of Tropical Depression Two in the Atlantic, east of Florida. This graphic will update to the current satellite imagery.


Figure 2. Official 5-day forecast for Tropical Depression Two. This graphic will remain current.

Forecast for TD2

The models are coming into better agreement as TD2 has become more organized. In terms of dynamical forecast models, the HWRF and GFS both forecast TD2 to max out just above tropical storm strenth. HWRF intensifies TD2 to around 47 mph in the next 24 hours, whereas GFS is a bit slower to bring the system up to tropical storm status. Two statistical models, the DSHP (SHIPS model that includes land interaction) and the LGEM (Logistical Growth Equation Model) both intensify TD2 to a moderate tropical storm over the next 2-3 days.

There tends to be a lot of uncertainty involved with tropical cyclones that form under these circumstances, but our forecast remains in line with the National Hurricane Center and the reliable forecast models. TD2 will move slowly to the northeast in weak steering currents over the next few days before eventually becoming an extratropical storm. There is minimal chance that this system will cross over Florida into the Gulf of Mexico. Timing and path depend heavily on how intense the cyclone gets, as Jeff mentioned in his blog earlier today. A weaker storm will tend to stay south, whereas a stronger storm will grow taller in the atmosphere and winds at higher levels will influence it and steer it northeast.

None of the reliable models predict tropical cyclone development over the remainder of the Atlantic through July 23.

Angela

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I'd give them above average marks, I only question the track.
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1008.9 mb
(~ 29.79 inHg)
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I'd give them an A. Right now this thing doesn't really look that great on the visible due to shear and D-min, it needs far more deep convection before it can be upgraded to a TS.
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TAZ does Masters get a poor rating too for this?
Member Since: July 14, 2008 Posts: 1 Comments: 9625
Quoting MrstormX:


*Special Upgrades



oh
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70. SLU
Quoting ackee:
HOW WOULD U RATE THE NHC HANDLE OF TD#2/Bert SO FAR

A GOOD

B FAIR

C AVERAGE

D POOR


C

From only 40% at 2pm when the system was looking in great shape to a TD at 5pm and possibly a TS at 8pm
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So Wunderground blog gets a D too?!
Member Since: July 14, 2008 Posts: 1 Comments: 9625
Quoting Tazmanian:



upgrades will come out 8pm or 11pm tonight


*Special Upgrades
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Quoting ackee:
HOW WOULD U RATE THE NHC HANDLE OF TD#2/Bert SO FAR

A GOOD

B FAIR

C AVERAGE

D POOR



E vary poor
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Quoting MrstormX:
So why no upgrade yet?



upgrades will come out 8pm or 11pm tonight
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Quoting ncstorm:
I dont know why people are saying that the models didnt predict development..in fact the ECWMF, CMC, NOGAPS and NAM predicted development..they weren't consistent with their runs but they did see something with the set up..thats why I had a problem with Dr. Masters statement with it none of the reliable models showing development early this week..
They were showing development but seems like a little further north. Predictions cannot be an exact science as conditions are constantly changing.
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And if it keeps going south that short wave is gonna have a less influence on it anyway.
Member Since: July 14, 2008 Posts: 1 Comments: 9625
Interesting that the 0Z and 12Z ECWMF runs both have a strong vort heading into the central GOMex from the wave that just left Africa. 12Z looks stronger though with closed isobars.

Have any other models developed this wave?
Member Since: September 3, 2007 Posts: 0 Comments: 519
HOW WOULD U RATE THE NHC HANDLE OF TD#2/Bert SO FAR

A GOOD

B FAIR

C AVERAGE

D POOR
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I do know the NHC has their "bad" moments, and I think this track is going to be one of them. There's absolutely no way that Bret is going NE with those very weak steering currents. It's going to continue to head south, and there will be TS Warnings for the Bahamas, and I won't be surprised if there's a TS Warning for some of Florida too.
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59. SLU
Quoting CybrTeddy:


Given the vortex message had 50 mph sustained.. I don't see why they can't give it 40 mph, I've seen worse looking TS before.
Quoting Stormchaser2007:


If recon is finding consistent 40-50mph winds, it's a TS regardless of what it looks like.


True. But this now reopens the barrel of anacondas concerning strong tropical waves in the deep tropics which don't get the benefit of the recon but have an excellent satellite representation and evidence of tropical storm conditions but because there are no direct observations they don't get named. This creates lots of confusion about the naming of tropical storms.
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So why no upgrade yet?
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with TD 2 no shutted landing this week
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Good afternoon.

Blog update:

Special Tropical Tidbit for Sunday, July 17th, with Video
Member Since: November 24, 2005 Posts: 628 Comments: 26455
I dont know why people are saying that the models didnt predict development..in fact the ECWMF, CMC, NOGAPS and NAM predicted development..they weren't consistent with their runs but they did see something with the set up..thats why I had a problem with Dr. Masters statement with it "none of the reliable models showing development" early this week..
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Quoting Tazmanian:



nop no going out too sea i get my crows ready
It better, I'm going to Myrtle Beach Tuesday.
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Got ridges from sea to shining sea this year, an no lil short wave is gonna yank this sucker out to sea, everything going westbound this year. Hell it might even go NE temporarily then go back west when new ridge comes back in.
Member Since: July 14, 2008 Posts: 1 Comments: 9625
T.C.F.W.
02L/TD/B/CX
MARK
28.13N/78.11W
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If anyone has a "best practice" for managing filters and minimizing the number of junk posts during active periods, please WU me. I currently have my filter set to show all posts and it's a bit of a task keeping up. Thank you.
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49. angelafritz (Admin)
To illustrate the usefulness of an ensemble prediction system, a few of the ensemble members from various models (mostly ECMWF) were playing around with this notion for the past week or so, ever since the boundary was forecast to drop into favorable warm waters. So although deterministic runs were ruling it out, the models, in a grander sense, were forecasting a low probability of this event to actually occur. And it is a low prob event - not very many of these tropical transitions actually come to fruition. Which is why it takes everyone by surprise! :)

Quoting caneswatch:


I have to agree with this. No, or barely any, computer models saw Bret coming. It throws everyone off-guard.
Quoting RitaEvac:
Yes, everybody listen to the models, it knows best. Just like they never had a clue this storm would form and move south. Models suck, and it aint going out to sea.



nop no going out too sea i get my crows ready
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Yep. Currently moving slowly SSE it appears. Upper winds and that ridge forming should keep it away from land but it's gonna be tight.
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WTNT01 KNGU 172101
WARNING ATCN MIL 02L NAT 110717203641

2011071718 98L NONAME 001 01 180 02 SATL 020
T000 277N 0782W 030
T012 274N 0782W 040 R034 050 NE QD 050 SE QD 050 SW QD 050 NW QD
T024 282N 0778W 045 R034 060 NE QD 060 SE QD 060 SW QD 060 NW QD
T036 290N 0773W 050 R050 030 NE QD 030 SE QD 020 SW QD 020 NW QD R034 075 NE QD 075 SE QD 075 SW QD 075 NW QD
T048 304N 0765W 050 R050 040 NE QD 040 SE QD 030 SW QD 030 NW QD R034 090 NE QD 090 SE QD 090 SW QD 090 NW QD
T072 320N 0735W 050 R050 040 NE QD 040 SE QD 030 SW QD 030 NW QD R034 090 NE QD 090 SE QD 090 SW QD 090 NW QD
T096 340N 0670W 045
T120 360N 0600W 040
AMP
NNNN
SUBJ: TROPICAL DEPRESSION NONAME (02L) WARNING NR 001
1. TROPICAL DEPRESSION NONAME (02L) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN ATLANTIC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
171800Z --- NEAR 27.7N 78.2W
MOVEMENT PAST SIX HOURS - 180 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 27.7N 78.2W
---
FORECASTS:
12 HRS, VALID AT:
180600Z --- 27.4N 78.2W
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 025 DEG/ 04 KTS
---
24 HRS, VALID AT:
181800Z --- 28.2N 77.8W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 030 DEG/ 05 KTS
---
36 HRS, VALID AT:
190600Z --- 29.0N 77.3W
MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 025 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
191800Z --- 30.4N 76.5W
MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 055 DEG/ 08 KTS
---
72 HRS, VALID AT:
201800Z --- 32.0N 73.5W
MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 070 DEG/ 15 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
211800Z --- 34.0N 67.0W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 070 DEG/ 15 KTS
---
120 HRS, VALID AT:
221800Z --- 36.0N 60.0W
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
172100Z POSITION NEAR 27.5N 78.2W OR APPROX 170NM NORTH OF
NASSAU, BAHAMAS.NEXT WARNINGS AT 180301Z, 180901Z,
181501Z AND 182101Z.//
BT
#0001
NNNN
0211071518 313N 804W 20
0211071600 310N 800W 20
0211071606 307N 797W 20
0211071612 304N 794W 20
0211071618 298N 791W 20
0211071700 293N 789W 20
0211071706 288N 785W 20
0211071712 282N 782W 20
0211071718 277N 782W 30

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New obs in, more TS winds.
39 knots
(~ 44.8 mph)

35 knots
(~ 40.2 mph)

35 knots
(~ 40.2 mph)
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Quoting Stormchaser2007:


If recon is finding consistent 40-50mph winds, it's a TS regardless of what it looks like.
agree facts is this should be upgraded to a TS the models and NHC really got this one wrong
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172106Z JUL 11
FM FLEWEACEN
TO WEATHER
BT
UNCLAS
MSGID/NLMOC/OVLY2/0087/JUL
OVLY/ATL STORM 02L/171800Z7/JUL/1OF1/TROP DEPRESSION 02L(02L)/METOC
TEXT/12//G/274200N5/0781200W8/D
TEXT/12//G/281200N3/0774800W6/S
TEXT/12//G/302400N9/0763000W6/S
TEXT/12//G/320000N5/0733000W3/S
TEXT/12//G/340000N7/0670000W3/S
TEXT/12//G/360000N9/0600000W6/S
LINE/6//G/274200N5/0781200W8/281200N3/0774800W6/3 02400N9/0763000W6
/320000N5/0733000W3/340000N7/0670000W3/360000N9/0 600000W6
ARC/0/G///281200N3/0774800W6/060NM/060NM
ARC/0/G///302400N9/0763000W6/090NM/090NM
ARC/0/G///320000N5/0733000W3/090NM/090NM
TEXT/12//G/254200N3/0754200W8/TROP DEPRESSION 02L
TEXT/12//G/244200N2/0754200W8/17 JUL 1800Z
TEXT/12//G/234200N1/0754200W8/MAX 30 KT
TEXT/12//G/224200N0/0754200W8/180 AT 02 KT
TEXT/12//G/214200N9/0754200W8/34 KT RADII SHOWN
TEXT/12//G/284200N6/0734800W2/1818Z MAX 45
TEXT/12//G/302400N9/0723000W2/1918Z MAX 50
TEXT/12//G/320000N5/0693000W8/2018Z MAX 50
TEXT/12//G/340000N7/0630000W9/2118Z MAX 45
TEXT/12//G/360000N9/0560000W1/2218Z MAX 40
ENDAT
BT
#0001
NNNN

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Quoting 7544:


just asking will this include se fla area also tia


Doubt it, unless it goes farther South.
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Quoting TaylorSelseth:
I think we have TS Bret now, that was fast.

Why are the models taking this out to sea? I don't see any strong NW steering.


Shortwave will move across the US and drag this to the NE in about 48-72 hours.
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39. 7544
Quoting MrstormX:
AMZ080-180330-
SW N ATLANTIC S OF 31N W OF 65W INCLUDING BAHAMAS
530 PM EDT SUN JUL 17 2011

...TROPICAL STORM WARNING FROM 26N TO 30N BETWEEN 76W AND 80W...

.TONIGHT AND MON...WITHIN 60 NM OF TROPICAL DEPRESSION TWO WINDS
25 TO 30 KT BECOMING TROPICAL STORM FORCE WINDS TONIGHT AND MON.
HIGHEST WINDS 45 KT GUSTS 55 KT. SEAS 8 TO 10 FT BUILDING TO 15
FT WITH SEAS 12 FT OR GREATER WITHIN AREA OF TROPICAL STORM
FORCE WINDS LATE TONIGHT AND MON. ELSEWHERE N OF 26N W OF 76W N
TO NE WINDS 15 TO 20 KT. SEAS 5 TO 8 FT. N OF 26N E OF 76W SE TO
S WINDS 10 TO 15 KT. SEAS 5 TO 7 FT. S OF 26N W OF 76W SE WINDS
5 TO 10 KT. SEAS 1 TO 2 FT. S OF 26N E OF 76W E TO SE WINDS 10
TO 15 KT EXCEPT 15 TO 20 KT S OF 22N E OF 74W. SEAS 4 TO 7 FT
EXCEPT 3 TO 5 FT W OF BAHAMAS.
.MON NIGHT THROUGH WED...TROPICAL STORM FORCE WINDS WITHIN 90 NM
OF CENTER. HIGHEST WINDS 50 KT GUSTS 60 KT. SEAS 12 FT OR
GREATER IN AREA OF TROPICAL STORM FORCE WINDS. HIGHEST SEAS 20
FT. ELSEWHERE WITHIN 150 NM OF TROPICAL STORM TWO WINDS 20 TO 30
KT. SEAS 8 TO 12 FT. ELSEWHERE N OF 27N W OF 77W NW TO N WINDS
10 TO 15 KT. SEAS 4 TO 7 FT. ELSEWHERE N OF 27N W OF 77W S TO
SW WINDS 15 TO 20 KT. SEAS 5 TO 8 FT. S OF 22N E OF 74W E TO SE
WINDS 15 TO 20 KT. SEAS 4 TO 7 FT. REMAINDER AREA SE WINDS 10
KT. SEAS 4 TO 6 FT EXCEPT 1 TO 3 FT W OF BAHAMAS.
.THU AND FRI...N OF 27N SW WINDS 10 TO 15 KT...EXCEPT 5 TO 10 KT
E OF 60W. SEAS 2 TO 4 FT. FROM 25N TO 27N SE TO S WINDS 5 TO 10
KT. SEAS 3 TO 4 FT...EXCEPT 1 TO 2 FT W OF BAHAMAS. FROM 23N TO
25N SE TO E WINDS 10 TO 15 KT. SEAS 4 TO 5 FT...EXCEPT 2 TO 3 FT
W OF BAHAMAS. S OF 23N E TO SE WINDS 10 TO 15 KT INCREASING TO
15 TO 20 KT FRI. SEAS 4 TO 6 FT INCREASING TO 5 TO 8 FT...EXCEPT
3 TO 5 FT W OF BAHAMAS.

$$
FORECASTER SCHAUER


just asking will this include se fla area also tia
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Yes, everybody listen to the models, it knows best. Just like they never had a clue this storm would form and move south. Models suck, and it aint going out to sea.
Member Since: July 14, 2008 Posts: 1 Comments: 9625
I just want to state for the record that I called this storm every since last week..toot!! yeah, I'm tooting my own horn..I said TS for tomorrow morning but it seems to want to intensify quicker which is now scary because it hasnt even had DMAX yet..However as I said this morning, I can see this becoming a hurricane and I still believe that..remember, Dr. Masters said, the stronger it gets, the more northward it will go
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18z Early Cycle NHC model tracks
TD #2
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)



Dynamic Models (More sophisticated models)




Early Model Wind Forecasts

Member Since: July 3, 2005 Posts: 414 Comments: 125613

Magnitude
4.9
Date-Time
Sunday, July 17, 2011 at 18:30:28 UTC
Sunday, July 17, 2011 at 08:30:28 PM at epicenter
Time of Earthquake in other Time Zones
Location
44.987°N, 11.369°E
Depth
10 km (6.2 miles)
Region
NORTHERN ITALY
Distances
55 km (34 miles) N of Bologna, Italy
58 km (36 miles) SSE of Verona, Italy
84 km (52 miles) ENE of Parma, Italy
355 km (220 miles) NNW of ROME, Italy

Shallow and felt quite a distance away.
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Quoting mcluvincane:
None of the reliable models predict tropical cyclone development over the remainder of the Atlantic through July 23.

I really think the Doc needs to leave this statement from his blog. Models? What models? are you kidding me



I have to agree with this. None, or barely any, computer models saw Bret coming. It throws everyone off-guard.
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I think we have TS Bret now, that was fast.

Why are the models taking this out to sea? I don't see any strong NW steering.
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Quoting SLU:
It's going to be a stretch for the NHC to call this a tropical storm. They will most likely wait until it develops some more deep convection 1st.



If recon is finding consistent 40-50mph winds, it's a TS regardless of what it looks like.
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Quoting SLU:
It's going to be a stretch for the NHC to call this a tropical storm. They will most likely wait until it develops some more deep convection 1st.



Given the vortex message had 50 mph sustained.. I don't see why they can't give it 40 mph, I've seen worse looking TS before.
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Quoting taco2me61:


Ops my Bad

Thank You Angela for the Up-Date....

and thank you MrstormX

Taco :o)


No Probs
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Quoting SLU:
It's going to be a stretch for the NHC to call this a tropical storm. They will most likely wait until it develops some more deep convection 1st.



we have seen storm march more wors then this in fac i re called one storm that got name wish was in the gulf under 50kt of shear
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Quoting CybrTeddy:
Another ob of TS winds uncontaminated..
43.8 knots (~ 50.4 mph)
Tropical Storm


Plus 50 mph, higher then the NHC expected.
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Quoting MrstormX:


No thank Angela, not Dr. M


Ops my Bad

Thank You Angela for the Up-Date....

and thank you MrstormX

Taco :o)
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26. SLU
It's going to be a stretch for the NHC to call this a tropical storm. They will most likely wait until it develops some more deep convection 1st.

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.