Hurricane Franklin

[CheeselandSkies]

That's what I'm saying. A lot of the recent ones we've seen that have survived (Isaias, Laura in particular) have been a situation where the decoupled "center" kind of skirts around the mountains and re-forms on the other side. Franklin just plowed straight across.

[Windspeed]

Looks like Franklin is going to find itself in an area of favorable upper divergence and a pocket of low wind shear in a few days as it swings west of Bermuda. Should be a solid poleward outflow jet to exhaust. Franklin is our first shot at a major. The TC models like it. Hopefully, it steers clear of coastal Canada. The Atlantic may find big ACE producers tough to come with uncertainties in the overall ASO pattern, but Franklin may give us a little bit here if it can go off over the weekend.

[mob1]

Recon finding extrapolated pressure of 997mb or so. 

Some hurricane models have it passing fairly close to Bermuda. 

[WxWatcher007]

Worth noting that both the operational GFS and Euro have continued trending toward a direct Atlantic Canada impact in about 6-7 days. That leaves a lot of time for changes but the east trend a few days ago completely reversed. 

[WxWatcher007]

12z Ensembles

[WxWatcher007]

 

[NorthHillsWx]

Franklin got shredded last night wow!!!

[Windspeed]

Yeah, it seems the mid-level shear is persisting and really doing a number on Franklin at this time.

[WxWatcher007]

12z ensemble guidance shifted significantly today toward no land impacts. 

Won’t really get talked about much because it means no impacts but it’s really interesting to see on ensemble and operational guidance. Still worth watching in Atlantic Canada.

[WxWatcher007]

Tropical Storm Franklin Discussion Number  22
NWS National Hurricane Center Miami FL       AL082023
1100 PM AST Fri Aug 25 2023

Westerly shear continues to affect Franklin tonight, as evidenced by 
the sharp edge to its cold cloud tops on infrared satellite images. 
However, the low-level center that was exposed earlier today appears 
to have moved under the western edge of the convective canopy. An 
Air Force Reserve Hurricane Hunter aircraft flew the storm at 700 mb 
this evening and reported peak flight-level winds of 56 kt, with 
believable SFMR winds in the 45-55 kt range. These data warrant a 
slight increase to the initial intensity (50 kt), especially given a 
recent dropsonde that suggests the surface pressure has fallen to 
996 mb tonight. A recent ASCAT-B pass over Franklin further supports 
this, with peak wind vectors slightly above 45 kt. Note that the 
initial intensity of Franklin is more uncertain than normal, with 
there being a large spread between some of the aircraft data and the 
various objective and subjective satellite estimates.

The intense convection closer to the center of Franklin appears to 
have drawn the surface center more northeastward, and the initial 
motion is an uncertain 60/7 kt. A high pressure ridge building to 
the east of Franklin is expected to steer the cyclone more northward 
and north-northwestward this weekend and into early next week. Then, 
a deep-layer trough is forecast to move across the northeastern U.S. 
and eastern Canada by midweek. This should cause Franklin to 
accelerate northeastward deeper into the mid latitudes through the 
end of the forecast period. The updated NHC track forecast lies to 
the east of the previous one during the first 60-72 h of the period, 
mainly a result of the eastward adjustment to the initial position 
of Franklin. There are some notable forward speed differences beyond 
72 h, with the GFS significantly faster than the rest of the global 
and regional models. With the NHC forecast remaining near the 
multi-model consensus aids, no notable changes were made to this 
portion of the track forecast.

The westerly shear that has plagued Franklin for the past couple of
days is expected to decrease during the next 24-36 h. So while only
modest strengthening is forecast in the near term, more significant
strengthening seems likely thereafter as the cyclone moves over
very warm SSTs (29-30 deg C) and within a more favorable dynamic
environment. The updated forecast shows Franklin becoming a
hurricane by 48 h and peaking near major hurricane intensity in
72-96 h, in good agreement with the latest HCCA and IVCN aids. As
Franklin accelerates to higher latitudes, cooler waters and
increased deep-layer shear will induce weakening and eventually
extratropical transition beyond the end of the forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT  26/0300Z 22.4N  66.2W   50 KT  60 MPH
 12H  26/1200Z 23.0N  66.0W   55 KT  65 MPH
 24H  27/0000Z 23.9N  66.3W   55 KT  65 MPH
 36H  27/1200Z 25.3N  67.0W   60 KT  70 MPH
 48H  28/0000Z 27.0N  67.9W   70 KT  80 MPH
 60H  28/1200Z 28.8N  68.4W   80 KT  90 MPH
 72H  29/0000Z 30.5N  68.4W   95 KT 110 MPH
 96H  30/0000Z 34.7N  66.5W   95 KT 110 MPH
120H  31/0000Z 40.0N  60.0W   75 KT  85 MPH

$$
Forecaster Reinhart

[Normandy]

This is a crazy odd storm structurally.  Certainly due to the heavy shear

[WxWatcher007]

Speaking of odd structure—it’s got a partial eyewall going at first light and possible eye. Recon en route but this could be a hurricane today if that keeps up.

[WxWatcher007]

Recon approaching the eye. 

[WxWatcher007]

988.9mb extrapolated pressure with a peak FL wind of 57kts. Some SFMR have been over 64kt, but apparently SFMR readings have been high in Franklin before. If it's not a hurricane, it's getting close. 

[WxWatcher007]

Closed eye per recon. 

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 26th day of the month at 11:57Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5306
Storm Name: Franklin
Storm Number & Year: 08 in 2023 (flight in the North Atlantic basin)
Mission Number: 11
Observation Number: 05 ( See all messages of this type for this mission. )

A. Time of Center Fix: 26th day of the month at 11:38:10Z
B. Center Fix Coordinates: 23.20N 66.54W
B. Center Fix Location: 333 statute miles (536 km) to the N (355°) from San Juan, Puerto Rico (U.S.).
C. Minimum Height at Standard Level: 3,000m (9,843ft) at 700mb
D. Minimum Sea Level Pressure: 989mb (29.21 inHg)
E. Dropsonde Surface Wind at Center: From 50° at 7kts (From the NE at 8mph)
F. Eye Character: Closed
G. Eye Shape & Diameter: Circular with a diameter of 18 nautical miles (21 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 49kts (56.4mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 9 nautical miles to the SSW (211°) of center fix at 11:35:30Z
J. Maximum Flight Level Wind Inbound: From 308° at 42kts (From the NW at 48.3mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 21 nautical miles (24 statute miles) to the SW (221°) of center fix at 11:32:00Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 68kts (78.3mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 13 nautical miles (15 statute miles) to the NE (39°) of center fix at 11:42:00Z
N. Maximum Flight Level Wind Outbound: From 133° at 57kts (From the SE at 65.6mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 14 nautical miles (16 statute miles) to the NE (41°) of center fix at 11:42:30Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 9°C (48°F) at a pressure alt. of 3,049m (10,003ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 14°C (57°F) at a pressure alt. of 3,047m (9,997ft)
R. Dewpoint Temp & Sea Surface Temp: Not Available
S. Fix Determined By: Penetration, Radar, Wind and Pressure
S. Fix Levels (surface & flight level centers within 5nm of each other): Surface and 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 3 nautical miles

Remarks Section:
 

Maximum Flight Level Wind: 57kts (~ 65.6mph) which was observed 14 nautical miles (16 statute miles) to the NE (41°) from the flight level center at 11:42:30Z
Maximum Flight Level Temp: 14°C (57°F) which was observed 6 nautical miles to the SSW (203°) from the flight level center

[WxWatcher007]

Should be a hurricane at 11am. Hurricane models get this to MH status in a few days and the NHC endorsed that in its 5am update. 

[hawkeye_wx]

The shear has become more favorable, but the core will have to mix the dry air out and build better convection over the next day or two.

[WxWatcher007]

Hurricane Franklin Discussion Number  24
NWS National Hurricane Center Miami FL       AL082023
1100 AM AST Sat Aug 26 2023

Franklin has become better organized this morning on satellite and 
microwave imagery.  An earlier SSMIS microwave pass showed a 
developing core with the mid and low-level center becoming more 
vertically aligned. Early visible satellite images showed a ragged 
eye, which has become cloud filled in the last hour or two.  Deep 
convection around Franklin has become more symmetric compared to 
recent days, likely due to a decrease in vertical wind shear.  Air 
Force and NOAA Hurricane Hunters have been in the system 
this morning, and found that the surface pressure has dropped to 
989 mb and SFMR winds were around 60 to 65 kt from both aircraft. 
Given the data from the aircraft reconnaissance, Franklin has been 
upgraded to a Hurricane, with the initial intensity set at 65 kt. 
Franklin is the second hurricane of the 2023 Atlantic hurricane 
season.

Franklin is moving north-northwestward at 6 kt.  A
north-northwestward to northward motion is forecast during the next 
few days as the storm moves along the western periphery of a 
mid-level ridge, taking it to the west of Bermuda on Tuesday.  By 
the middle of next week, a faster northeastward motion is expected 
when Franklin moves in between the ridge and a mid- to upper-level 
trough over eastern Canada and the northeastern United States.  The 
track models have shifted to the west once again this cycle, and the 
NHC track forecast follows that trend and is slightly slower than 
the previous one at long ranges.

Franklin is expected to steadily strengthen during the next few days 
with lower vertical wind shear, and warm sea surface temperatures in 
the western Atlantic.  Franklin is forecast to become a major 
hurricane early next week.  The strengthening trend should end in 
about 3 to 4 days with shear expected to increase. By Day 5, the 
system will move over much cooler SSTs leading to increased 
weakening.  The intensity models are higher this cycle, and the NHC 
forecast has been nudged upward, but still remains below the IVCN 
and HCCA consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  26/1500Z 23.5N  66.7W   65 KT  75 MPH
 12H  27/0000Z 24.2N  67.0W   70 KT  80 MPH
 24H  27/1200Z 25.4N  67.8W   80 KT  90 MPH
 36H  28/0000Z 27.0N  68.8W   90 KT 105 MPH
 48H  28/1200Z 28.5N  69.4W  100 KT 115 MPH
 60H  29/0000Z 30.2N  69.5W  105 KT 120 MPH
 72H  29/1200Z 31.9N  69.0W  105 KT 120 MPH
 96H  30/1200Z 35.6N  65.9W   90 KT 105 MPH
120H  31/1200Z 40.5N  56.9W   75 KT  85 MPH

$$
Forecaster Kelly/Pasch

[Hazey]

Bermuda might be back in the game for direct effects. Looking less impactful for the Canadian maritimes. YYT still has to watch this.

[Floydbuster]

Wow 120 mph Category 3 hurricane is quite the impressive storm. We'll see if Franklin can make a go at it.

[hawkeye_wx]

The latest center dropsonde recorded 986 mb.

[WxWatcher007]

 

[Normandy]

Franklin appears to have been one of these storms where once shear let go it instantly became a strong hurricane.  Perhaps the mid level vortex was already very strong and the shear was simply displacing it east.  Fascinating to watch unfold!

[Eskimo Joe]

 

[WxWatcher007]

I am really fascinated by this. It has been a truly appalling performance by the models on Franklin. Now the Euro basically takes Franklin from west to east near or over Bermuda. These are massive shifts at medium range. 

[WxWatcher007]

The 12z Euro basically leaves Franklin behind after looping over Bermuda! That's like a 1500 mile trend over 24 hours. That's extraordinary, and would almost certainly make Franklin a big ACE producer. 

[Normandy]

Agree with you.  Wild model swings and a very chaotic pattern is indeed fascinating to watch

[Torch Tiger]

2 hours ago, WxWatcher007 said:

I am really fascinated by this. It has been a truly appalling performance by the models on Franklin. Now the Euro basically takes Franklin from west to east near or over Bermuda. These are massive shifts at medium range. 

Of course it basically nails the NE US/E CA trough 

[Ed, snow and hurricane fan]

First major of the season tomorrow.  I don't follow ACE that closely during the season, but lots of names and not that much ace, between Franklin and TD 10 which I'm guessing becomes an H, come closer to the 130 to 160 forecasts I've seen.

[Chinook]

recent recon data says up to 73-74 kt at flight level, and something like 70-72 kt at surface level, sea level pressure 977mb