ATL: DORIAN - Post-Tropical - Discussion

[Extratropical94]

All low-level missions into Dorian.

[supercane4867]

Satellite presentation defiently improving. Could pull an Alex 2004. Nova Scotia watch out

[birdwomn]

This storm does not want to die. The Lyrics from Fame keep going through my head...
I wanna live forever, you will remember my name....(or something like that)

[Hurricane Jed]

We will be talking about this one for years

[Hurricane Jed]

Haven’t seen a storm this resilient in quite awhile

[CrazyC83]

There is no record of a major hurricane hitting Atlantic Canada. I only know of two category 2 storms: Ginny in 1963 (90 kt / 948mb in western NS as it became extratropical) and Juan in 2003 (85 kt / 973mb near Halifax, an incredibly resilient storm).

[CyclonicFury]

Dorian has come such a long way from when it was a tiny ITCZ disturbance in the MDR two weeks ago.

[Hypercane_Kyle]

The last stretch of one of the worst hurricanes in modern history.

[CrazyC83]

The last stretch of one of the worst hurricanes in modern history.

https://i.imgur.com/lvMCefm.jpg

Not quite the last stretch?

Given the last flight supporting 80 kt and its improvement, I would go with 90 kt right now and a pressure of 950mb.

[Hypercane_Kyle]

The last stretch of one of the worst hurricanes in modern history.

https://i.imgur.com/lvMCefm.jpg

Not quite the last stretch?

Given the last flight supporting 80 kt and its improvement, I would go with 90 kt right now and a pressure of 950mb.

Sorry, I mean the last stretch of the storm intensifying and heading towards a landmass.

[supercane4867]

Not very often to see people in Canada waiting in long lines for hurricane preparation

 https://twitter.com/CBCNS/status/1170026739898245123



 https://twitter.com/CBCNS/status/1170020978375778310

[Hybridstorm_November2001]

For those interested, I'll post frequent updates on my severe weather blog chronicling Dorian's approach (sat images, radar images, weather charts, warnings, exact) later this evening. I'm located close to the Maine border in SW New Brunswick so I should miss the worst of it here. Areas like Nova Scotia, Prince Edward Island and the SE Corner of my own province (East of the Provincial capital of Federicton located in South-Central NB) could take a very bad hit from this one -

http://hybridstorm-weatherblog.blogspot.com/

[supercane4867]

Tropical cyclone technical information statement issued by the
Canadian Hurricane Centre of Environment Canada at 2.38 PM ADT
Friday 06 September 2019.

The next statement will be issued by 9.00 PM ADT

1. Current position, strength, central pressure and motion

At 3.00 PM ADT, hurricane Dorian was located near latitude 36.4 N and
longitude 73.8 W, about 109 nautical miles or 202 km northeast of
Cape Hatteras. Maximum sustained winds are estimated at 80 knots (148
km/h) and central pressure at 958 MB. Dorian is moving northeast at
18 knots (32 km/h).

2. Forecast position, central pressure and strength

Date time lat lon MSLP Max wind
ADT MB kts kmh
Sep 06 3.00 PM 36.4N 73.8W 958 80 148
Sep 06 9.00 PM 37.5N 72.2W 965 80 148
Sep 07 9.00 AM 40.4N 68.0W 965 75 139
Sep 07 9.00 PM 44.4N 64.0W 960 75 139
Sep 08 9.00 AM 48.9N 60.2W 960 70 130 post-tropical
Sep 08 9.00 PM 51.7N 55.1W 963 60 111 post-tropical
Sep 09 9.00 AM 54.5N 48.7W 971 50 93 post-tropical
Sep 09 9.00 PM 56.1N 43.0W 979 45 83 post-tropical


3. Technical discussion

A. Analysis

Dorian made landfall over Cape Hatteras, North Carolina, this morning
as a strong category 1 hurricane with sustained winds of 80 knots.
Dorian has a fairly large eye as evident on ir satellite imagery and
convection has remained persistent around all quadrants this
afternoon. Earlier today there were hints of dry air wrapping around
the inner core, however latest imagery shows more concentric moisture
surrounding the eye. The hurricane is about to enter an environment
characterized by increasing deep layer shear which could lead to some
weakening of the system tonight and into Saturday as it approaches
Atlantic Canada. Current shear values off the Carolina coast range
from 20 to 30 knots. Dorian has been gaining latitude today, with a
forward speed of around 18 knots.

B. Prognostic

Hurricane Dorian will continue to encounter stronger shear which will
contribute to a gradual weakening. This slow decrease in intensity
will continue as the hurricane begins to race towards Atlantic
Canada. However, the rate of weakening could be balanced by some
baroclinic forcing, and the foercast reflects a very slow weakening
trend. Model guidance has shifted to the west the past few cycles and
the latest track reflects that, showing a land-falling category one
hurricane near Halifax or east of Halifax Saturday evening. Dorian
will begin extra-tropical transition Saturday evening over Nova
Scotia, completing the process over the Eastern Gulf of St. Lawrence
early Sunday morning. Dorian will remain a very potent post-tropical
system with hurricane or near hurricane force winds as it crosses
Northern Newfoundland Sunday evening.

Global models continue to suggest large amounts of rain north of the
track with most models indicating widespread 50 to 100 mm for Nova
Scotia, Prince Edward Island, Southeastern New Brunswick and the Gulf
of St. Lawrence including the Quebec Lower North Shore. There could
be a swath in excess of 150 mm just north and west of Dorian's track.

C. Predicted wind radii (NM)

Time gales storms hurricane
NE SE SW NW NE SE SW NW NE SE SW NW
06/18Z 245 255 180 140 100 105 80 80 60 55 50 55
07/00Z 245 260 190 145 100 110 80 80 55 55 50 55
07/12Z 255 275 200 160 110 145 95 85 60 65 55 55
08/00Z 270 280 210 180 110 175 100 90 65 70 55 45
08/12Z 265 275 220 195 95 145 90 90 55 50 30 45
09/00Z 240 265 225 195 75 100 70 80 0 0 0 0
09/12Z 210 255 225 190 60 90 50 65 0 0 0 0
10/00Z 210 255 260 190 0 0 0 0 0 0 0 0


END/MARCH/MERCER

[CrazyC83]

Not very often to see people in Canada waiting in long lines for hurricane preparation

https://twitter.com/CBCNS/status/1170026739898245123
https://twitter.com/CBCNS/status/1170020978375778310

I think they've seen the images from elsewhere and realize, this is serious. AFAIK, there has never been a Hurricane Warning for Halifax before (although there would have certainly been one for Juan in 2003 if Canada issued the products then; there was very little preparation for that storm).

[bob rulz]

It's hard to imagine that this hasn't strengthened somewhat based on sat presentation. When is the next recon?

[aperson]

SHIPS 18z is still showing non-zero RI probabilities.

SHIPS Prob RI for 20kt/ 12hr RI threshold= 6% is 1.2 times climatological mean ( 5.2%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 0% is 0.0 times climatological mean (10.9%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 6.9%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 3.8%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 0% is 0.0 times climatological mean ( 2.4%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 0% is 0.0 times climatological mean ( 4.5%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 0% is 0.0 times climatological mean ( 4.6%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 0% is 0.0 times climatological mean ( 5.4%)

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 1. 2. 3. 4. 6. 8. 9. 10. 11. 11. 12. 12.
SST POTENTIAL 0. -1. -3. -5. -11. -18. -26. -35. -40. -44. -48. -50.
VERTICAL SHEAR MAG -2. -5. -9. -13. -21. -26. -31. -36. -38. -41. -43. -46.
VERTICAL SHEAR ADJ -1. -1. -1. -2. -3. -4. -5. -6. -6. -5. -4. -4.
VERTICAL SHEAR DIR 0. 1. 1. 2. 3. 5. 6. 8. 9. 10. 12. 13.
PERSISTENCE 0. -1. -1. -1. 0. 0. 0. 0. 0. 0. 0. 0.
200/250 MB TEMP. 0. -1. -1. -2. -4. -6. -6. -7. -7. -8. -9. -11.
THETA_E EXCESS 0. -1. -2. -2. -3. -4. -4. -4. -4. -4. -3. -3.
700-500 MB RH 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1. 1.
MODEL VTX TENDENCY 0. 2. 5. 7. 10. 4. -10. -16. -17. -18. -19. -20.
850 MB ENV VORTICITY 0. 0. 0. 1. 2. 4. 6. 7. 8. 8. 9. 10.
200 MB DIVERGENCE 0. 1. 1. 2. 3. 3. 3. 2. 2. 1. -1. -3.
850-700 T ADVEC 0. 0. 0. 0. 0. -1. -2. -3. -3. -2. -2. -1.
ZONAL STORM MOTION 0. 0. 0. 0. -1. -2. -3. -3. -5. -7. -9. -9.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
GOES PREDICTORS 1. 1. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
RI POTENTIAL 0. -1. -2. -3. -4. -4. -3. -2. 0. 1. 2. 3.
----------------------------------------------------------
TOTAL CHANGE -1. -3. -5. -10. -21. -39. -65. -82. -89. -97.-103.-109.

(ref: ftp://ftp.nhc.noaa.gov/atcf/stext, ftp://ftp.nhc.noaa.gov/atcf/stext/19090 ... _ships.txt)

[CrazyC83]

It's hard to imagine that this hasn't strengthened somewhat based on sat presentation. When is the next recon?

There are no more Recon flights.

[CrazyC83]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 06 SEP 2019 Time : 182012 UTC
Lat : 36:19:48 N Lon : 73:27:35 W


CI# /Pressure/ Vmax
5.3 / 952.9mb/ 97.2kt


Final T# Adj T# Raw T#
5.3 5.6 5.6

Estimated radius of max. wind based on IR : 25 km

Center Temp : +14.1C Cloud Region Temp : -56.9C

Scene Type : EYE

Subtropical Adjustment : OFF

Extratropical Adjustment : FLG

Positioning Method : ARCHER POSITIONING

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 172nmi
- Environmental MSLP : 1012mb

Satellite Name : GOES16
Satellite Viewing Angle : 42.1 degrees

****************************************************

[CrazyC83]

20190906 1801 36.2 73.7 T5.0/5.0 05L DORIAN

It was T4.5 when it passed Hatteras and T4.0 last night.

[bob rulz]

It's hard to imagine that this hasn't strengthened somewhat based on sat presentation. When is the next recon?

There are no more Recon flights.

It's still a threat to land, why stop recon?