Hurricane Don | peak 75mph 988mb | post tropical

[StretchCT]

Didn't really want to spend too much time on this but it's starting to get that look. NHC upped to 60% in 48 hrs. It's forecast to meander the Atlantic for the next 10 days, so just a problem for anyone crossing the Atlantic.  

Edited July 24, 2023 by StretchCT

[StretchCT]

Subtropical Storm Don is formed

500 AM AST Fri Jul 14 2023
 
...SUBTROPICAL STORM DON FORMS OVER THE CENTRAL ATLANTIC...
 
 
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...32.9N 46.8W
ABOUT 1165 MI...1875 KM WSW OF THE AZORES
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

 

Edited July 14, 2023 by StretchCT

[StretchCT]

11:00 AM AST Sat Jul 15
Location: 36.5°N 48.8°W
Moving: NW at 9 mph
Min pressure: 1006 mb
Max sustained: 45 mph
 

Not going to do much damage...

INIT  15/1500Z 36.5N  48.8W   40 KT  45 MPH
 12H  16/0000Z 37.8N  48.9W   35 KT  40 MPH
 24H  16/1200Z 39.1N  48.3W   35 KT  40 MPH
 36H  17/0000Z 39.5N  46.7W   35 KT  40 MPH
 48H  17/1200Z 39.3N  44.6W   35 KT  40 MPH
 60H  18/0000Z 38.4N  42.9W   35 KT  40 MPH
 72H  18/1200Z 36.8N  41.9W   35 KT  40 MPH
 96H  19/1200Z 33.9N  41.5W   35 KT  40 MPH
120H  20/1200Z 33.0N  42.0W   40 KT  45 MPH

[Iceresistance]

It's now a Subtropical Depression

[StretchCT]

Still there...

9:00 AM GMT Mon Jul 17
Location: 39.2°N 44.7°W
Moving: E at 9 mph
Min pressure: 1011 mb
Max sustained: 35 mph

[StretchCT]

I chuckled when I saw this.

[StretchCT]

Don "strengthened" overnight and was classified as Tropical.  As such the thread is updated from Subtropical to Tropical Storm.

Spoiler

Tropical Storm Don Discussion Number  16
NWS National Hurricane Center Miami FL       AL052023
300 AM GMT Tue Jul 18 2023

The convective structure of Don this evening has improved somewhat, 
with a decent area of -55 to -65C cold cloud tops centered a bit to 
the northeast of the low-level center. The center is also perhaps a 
bit better defined than earlier, with the ongoing convective 
activity possibly helping to tighten the center up. While subjective 
Dvorak classifications have not increased much this evening, an 
ASCAT-C pass at 2302 UTC caught the eastern portion of the 
circulation, with several believable wind vectors of up to 35 kt. 
Thus, Don is being upgraded to a tropical storm this advisory with 
sustained winds of 35 kt.

FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0900Z 36.3N  39.6W   35 KT  40 MPH
 12H  18/1800Z 35.2N  39.0W   35 KT  40 MPH
 24H  19/0600Z 34.2N  39.1W   35 KT  40 MPH
 36H  19/1800Z 33.8N  39.8W   40 KT  45 MPH
 48H  20/0600Z 33.7N  41.0W   40 KT  45 MPH
 60H  20/1800Z 34.3N  42.3W   45 KT  50 MPH
 72H  21/0600Z 35.2N  44.1W   45 KT  50 MPH
 96H  22/0600Z 38.0N  48.0W   45 KT  50 MPH
120H  23/0600Z 42.0N  49.0W   45 KT  50 MPH

 

 

 

[StretchCT]

Don is back up to 50mph and 1002mb and is forecast to get to 60mph now.

FORECAST POSITIONS AND MAX WINDS

INIT  20/0900Z 34.1N  41.6W   45 KT  50 MPH
 12H  20/1800Z 34.4N  42.7W   50 KT  60 MPH
 24H  21/0600Z 35.0N  44.4W   50 KT  60 MPH
 36H  21/1800Z 36.1N  46.3W   50 KT  60 MPH
 48H  22/0600Z 37.7N  48.0W   50 KT  60 MPH
 60H  22/1800Z 39.3N  49.2W   45 KT  50 MPH
 72H  23/0600Z 41.3N  49.7W   45 KT  50 MPH
 96H  24/0600Z 45.0N  47.0W   35 KT  40 MPH...POST-TROPICAL
120H  25/0600Z 47.0N  40.0W   30 KT  35 MPH...POST-TROPICAL

Don looks legit now.

[StretchCT]

[Iceresistance]

Now at 60 mph and 998 mb

[StretchCT]

Don overachieved. But is heading towards cooler waters. This is again its expected peak.

Disco below.  Was thinking maybe there was some kind of baroclinic forcing on it (didn't have time to look at maps) but the NHC says it strengthened due to the gulf stream.  

Spoiler

Hurricane Don Discussion Number  35
NWS National Hurricane Center Miami FL       AL052023
500 PM AST Sat Jul 22 2023

Don's cloud pattern continued to become better organized after the 
release of the previous advisory with convection wrapping around an 
eye in infrared imagery.  Since that time, the cloud tops over the 
western semicircle have warmed somewhat, but a 1648 UTC AMSR2 
microwave pass showed a well-defined low- to mid-level eye with deep 
convection surrounding it.  Subjective Dvorak estimates at 1800 UTC 
ranged from T4.0 (65 kt) from TAFB and T3.5 (55 kt) from SAB, with 
objective estimates in the 60 to 63 kt range.  Since subjective 
estimates have yielded a T4.0 throughout much of the afternoon, the 
initial intensity has been raised to 65 kt, making Don a hurricane.

Today's strengthening was the result of the storm passing over the 
warmer waters of the Gulf Stream, however it will move north of 
those warmer waters later this evening, and Don has likely peaked in 
intensity.  Weakening should begin overnight, with a faster rate of 
weakening expected Sunday through Monday as Don moves over even 
colder waters and the vertical wind shear increases. The cyclone is 
expected to become post-tropical by Sunday night, and dissipate by 
Monday night or early Tuesday.

Don is moving northward or 005 degrees at 10 kt. The cyclone is 
forecast to turn northeastward late tonight as it becomes embedded 
within southwesterly flow between a ridge to its east and a broad 
trough over eastern Canada.  A northeastward to east-northeastward 
motion should then continue until the system dissipates in 2-3 days. 
The track guidance is again tightly clustered and no significant 
changes to the previous official forecast were required.


FORECAST POSITIONS AND MAX WINDS

INIT  22/2100Z 40.1N  50.0W   65 KT  75 MPH
 12H  23/0600Z 42.0N  49.6W   60 KT  70 MPH
 24H  23/1800Z 44.5N  47.6W   50 KT  60 MPH
 36H  24/0600Z 46.4N  44.5W   40 KT  45 MPH...POST-TROPICAL
 48H  24/1800Z 47.7N  40.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  25/0600Z...DISSIPATED

$$
Forecaster Brown

Not bad looking either.

 

Edited July 22, 2023 by StretchCT

[StretchCT]

11:00 AM AST Sun Jul 23
Location: 43.9°N 47.8°W
Moving: NNE at 16 mph
Min pressure: 993 mb
Max sustained: 65 mph

[clm]

Wonder why they named it Don and not Donald.  😁

[StretchCT]

Don goes post tropical after 42 advisories and 10 days. It is the fifth longest running cyclone in July. See spoiler.


Post-Tropical Cyclone Don Advisory Number  42
NWS National Hurricane Center Miami FL       AL052023
300 PM GMT Mon Jul 24 2023

...DON NOW A POST-TROPICAL CYCLONE...
...THIS IS THE LAST ADVISORY...


SUMMARY OF 300 PM GMT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...47.6N 40.7W
ABOUT 585 MI...940 KM E OF CAPE RACE NEWFOUNDLAND
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...ENE OR 70 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 300 PM GMT (1500 UTC), the center of Post-Tropical Cyclone Don
was located near latitude 47.6 North, longitude 40.7 West. The
post-tropical cyclone is moving toward the east-northeast near 20
mph (31 km/h), and this general motion is expected to continue until
dissipation tomorrow.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Don should continue to gradually weaken, before dissipating
tomorrow.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
from the center.

The estimated minimum central pressure is 1007 mb (29.74 inches).


HAZARDS AFFECTING LAND
----------------------
None

 

Spoiler

Post-Tropical Cyclone Don Discussion Number  42
NWS National Hurricane Center Miami FL       AL052023
300 PM GMT Mon Jul 24 2023

Satellite imagery shows that Don lacks sufficient deep convection to 
classify the system as a tropical cyclone, and it is now post 
tropical.  The initial wind speed remains at 40 kt for this 
advisory, based on a recent ASCAT-B scatterometer pass.  Don should 
slowly weaken over the next day or so while moving over cold waters 
and within high vertical wind shear.

The system is moving east-northeastward at about 17 kt, and this
general motion will likely to continue until Don dissipates in
about a day.  Most of the global guidance has post-tropical Don
opening up into a trough and becoming absorbed by a larger
extratropical low over the north Atlantic tomorrow. Very few changes
were made to the previous NHC forecast.

Don has been a very long-lasting tropical cyclone (including
subtropical stages) for the month of July.  Preliminary data
indicate that the storm is the 5th longest-lasting system on record
for the month, just behind Emily of 2005.

This is the last advisory on Don.  Additional information on this
system can be found in High Seas Forecasts issued by the National
Weather Service...under AWIPS header NFDHSFAT1 and WMO header
FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSDAT1.php


FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 47.6N  40.7W   40 KT  45 MPH...POST-TROPICAL
 12H  25/0000Z 48.1N  36.9W   35 KT  40 MPH...POST-TROPICAL
 24H  25/1200Z...DISSIPATED