Hurricane Franklin

[tiger_deF]

Figured I'd make a thread for this disturbance. 90L has come on the scene rather quickly - As a disturbance from the western edge of the monsoon trough, models only started picking up on potential development of this system a few days ago. 90L has appeared to be steadily organizing over the past day, with popcorning CBs and early indications of banding patterns. Model-wise, a powerful trough is expected to pick up the developing system through Hispaniola and potentially posing a threat to Bermuda down the line. However, as indicated by the GEFS spaghetti plot, there are lots of options still on the table, and a great deal of uncertainty as to the future track.

[WxWatcher007]

Near the Windward Islands (AL90):
A broad area of low pressure has formed near the Windward Islands, 
shower and thunderstorm activity has become better organized since 
yesterday. Some additional development of this system is likely and 
a tropical depression could form by early next week while this 
system moves westward to west-northwestward at 10 to 15 mph, across 
the Lesser Antilles and over the eastern and central Caribbean Sea. 
Regardless of development, heavy rainfall is possible over portions 
of the Windward Islands during the next couple of days.  Interests 
in the eastern and central Caribbean should monitor the progress of 
this system.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...60 percent.

 

[ldub23]

1 hour ago, tiger_deF said:

Figured I'd make a thread for this disturbance. 90L has come on the scene rather quickly - As a disturbance from the western edge of the monsoon trough, models only started picking up on potential development of this system a few days ago. 90L has appeared to be steadily organizing over the past day, with popcorning CBs and early indications of banding patterns. Model-wise, a powerful trough is expected to pick up the developing system through Hispaniola and potentially posing a threat to Bermuda down the line. However, as indicated by the GEFS spaghetti plot, there are lots of options still on the table, and a great deal of uncertainty as to the future track.

Keep us  updated. Good work.

[WxWatcher007]

Just a super early nonsensical thought: even though we’re almost certainly going to see troughing, I think we’ll need to see how this looks after crossing the Antilles into the Atlantic to have a good sense of if it gets picked up and swept out to sea or left behind.

Given the anomalous troughing out east this year, and the parade of waves (which I think increases odds this never touches land after the Antilles) I think this will be complicated for a while. 

[WxWatcher007]

I see no reason why this can’t continue organizing in the near term. I mentioned the other day that the environment was conducive for intense convective activity and we’re seeing it so far. That’ll probably help in the next few days.

The environment has a decreasing influence of SAL and if anything I think the shear just to the north is looking like the detrimental factor to significant development in the Caribbean. 

[hawkeye_wx]

The morning visible loop shows that 90L has developed a closed circulation.  There is some shear, so convection is trying to hold onto the east side of the center.

[WxWatcher007]

43 minutes ago, hawkeye_wx said:

The morning visible loop shows that 90L has developed a closed circulation.  There is some shear, so convection is trying to hold onto the east side of the center.

Yeah, it looks like it's close if not already a TC. We'll see what recon finds later. 

[WxWatcher007]

[ldub23]

41 minutes ago, WxWatcher007 said:

Yeah, it looks like it's close if not already a TC. We'll see what recon finds later. 

JB  is  not giving  up. He doesnt mention hazel but  it formed  in the same  place

 

 

[WxWatcher007]

Did a deep dive on the Gulf and 90L in the MA subforum thread, but reposting the 90L portion here:

Invest 90L
This one is worth watching IMO. I think it is a contender to be the strongest system of the season thus far in the long range. Recon is expected to sample this later today and I believe they will find a tropical storm. 

In the visible you can clearly see a low level circulation, but there are some significant issues keeping this from taking off. There is very evident northerly shear that is pushing the convective burst that should be over the center further south. That's how we can see that there is a clear LLC  

In addition to the shear, there is dry air to the north that is causing issues as well. I don't expect dry air to be as big an issue long term, but for now the shear/dry air combo is keeping this one in check. This would be taking off IMO without the combination, because the convective bursts that we have seen have been persistent and intense--really allowing this to be as organized (and it's not terribly organized) as it is now. 

I'm intrigued by the long range because it looks like the environment after a potential landfall near DR/Haiti will be conducive for additional development. In fact, both the GFS and Euro operational guidance has this becoming a strong system in the open Atlantic. 

I still think we need to wait for this to cross the Antilles back into the Atlantic before fully understanding the long term future of 90L, but overall, troughing is going to lift this north into the Atlantic.

How far west this gets before that turn seems important, and certainly what other impulses in the Atlantic exist ahead of 90L, because both the Euro and GFS have a ridge over the CONUS and have trended toward a subtropical ridge building in to drive what is likely a named storm by then northward. Throw in any kind of trough in there to either cause a weakness between the ridges to go OTS, or in the case of a cutoff in the east change steering toward land, and we have a very complex forecast.  

Given the complexity of the forecast long range, and the shift west we've seen in ensemble guidance as 90L continues to develop, this one is certainly worth a close eye in Bermuda, Atlantic Canada, and to a lesser extent the US east coast. 

A lot of tracking to do this week. 

[Ed, snow and hurricane fan]

It looks like shear and mid-level humidity don't look terrible, but there seems to be an almost exposed center, although latest images thunderstorms are trying to build North.  May be partially exposed, but that looks like a closed tropical low to me.

[Ed, snow and hurricane fan]

Most of the GFS ensembles curve this N into the Atlantic, but there are some weaker ensembles that get it into the W Caribbean.  Not an obvious Gulf threat, the death ridge should keep anything moving W, but still interesting.

[SnoSki14]

Should be a depression soon given well defined LLC & convection 

[WxWatcher007]

I fully expect recon to find a TS here. Recon descending into the invest now. 

[WxWatcher007]

Whew, this latest set of obs from recon is interesting. We'll see if it's enough for the NHC. 

1000.4mb (extrapolated at ~1,300ft) with a pretty sharp wind shift. 

Peak FL wind obs between 45-50kt with peak SFMR obs between 45-56kts, none rain contaminated. 

[hawkeye_wx]

We'll have to wait and see what recon finds for wind direction in the other quadrants, but it seems likely we'll have TS Franklin at 5pm.

[hlcater]

17 minutes ago, WxWatcher007 said:

Whew, this latest set of obs from recon is interesting. We'll see if it's enough for the NHC. 

1000.4mb (extrapolated at ~1,300ft) with a pretty sharp wind shift. 

Peak FL wind obs between 45-50kt with peak SFMR obs between 45-56kts, none rain contaminated. 

Lol I was about to come in here and say you could make an argument for classifying this based on vis. I didn't know recon is in there. Clearly a closed low on the eastern side of the convective shield.

 

Also with the minimum extrap of 1000.5. Very nice little low in there.

[tiger_deF]

Very strong convective burst occurring slightly to the East of the low level center. Definitely looks to be strengthening quicker than forecast (most models didn't bring 90L down to 1001 mb until right before landfall/in the open Atlantic). Will be interesting to see how this affects the track. 

[WxWatcher007]

8 minutes ago, tiger_deF said:

Very strong convective burst occurring slightly to the East of the low level center. Definitely looks to be strengthening quicker than forecast (most models didn't bring 90L down to 1001 mb until right before landfall/in the open Atlantic). Will be interesting to see how this affects the track. 

Yeah I really want to see how it impacts the guidance, which has trended westward quite a bit recently. 

[mob1]

Some models have it affecting either the far eastern US (Nantucket or eastern Maine) or the Canadian maritimes.

Euro in general has a lot of traffic in the entire basin. 

[WxWatcher007]

 

[Stormchaserchuck1]

3 hours ago, WxWatcher007 said:

Major hurricane when it's near the Mid-Atlantic/New England is very interesting, especially considering where it already is. Some 12z GFS ensembles have a 500mb low pulling it toward the coast. 

[WxWatcher007]

Tropical Storm Franklin advisories coming at 5pm. 

[WxWatcher007]

First VDM

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 20th day of the month at 20:35Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 05 ( See all messages of this type for this mission. )

A. Time of Center Fix: 20th day of the month at 19:54:07Z
B. Center Fix Coordinates: 14.65N 67.05W
B. Center Fix Location: 268 statute miles (431 km) to the SSW (194°) from San Juan, Puerto Rico (U.S.).
C. Minimum Height at Standard Level: Not Available
D. Minimum Sea Level Pressure: 1002mb (29.59 inHg) - Extrapolated
E. Dropsonde Surface Wind at Center (Undecoded): NA
F. Eye Character: Not Available
G. Eye Shape: Not Available
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: Not Available
I. Location & Time of the Estimated Maximum Surface Wind Inbound (Undecoded): NA
J. Maximum Flight Level Wind Inbound: From 61° at 36kts (From the ENE at 41.4mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 20 nautical miles (23 statute miles) to the NNW (330°) of center fix at 19:48:41Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: Not Available
M. Location & Time of the Estimated Maximum Surface Wind Outbound (Undecoded): NA
N. Maximum Flight Level Wind Outbound: From 156° at 32kts (From the SSE at 36.8mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 66 nautical miles (76 statute miles) to the SE (137°) of center fix at 20:12:58Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 26°C (79°F) at a pressure alt. of 519m (1,703ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 27°C (81°F) at a pressure alt. of 523m (1,716ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 24°C (75°F)
R. Sea Surface Temp (collected at same location as temp inside eye): 29°C (84°F)
S. Fix Determined By: Penetration, Wind and Pressure
S. Fix Level: 1,500 feet
T. Navigational Fix Accuracy / Meteorological Accuracy (Undecoded): 0.01 / NA

Remarks Section - Remarks That Were Decoded...
 

Maximum Flight Level Wind: 51kts (~ 58.7mph) which was observed 64 nautical miles (74 statute miles) to the NE (43°) from the flight level center at 18:09:34Z

Remarks Section - Additional Remarks...
 

SLP EXTRAP FROM 1500FT RA

[WxWatcher007]

No surprise, but forecast to become a hurricane in the first advisory package.

Tropical Storm Franklin Discussion Number   1
NWS National Hurricane Center Miami FL       AL082023
500 PM AST Sun Aug 20 2023

This afternoon we have received a wealth of data from both a NOAA
reconnaissance mission and satellite imagery near the area of low
pressure located in the eastern Caribbean Sea. Earlier visible
satellite imagery showed the system had likely formed a tight
low-level vortex based on the earlier cloud motions before a
convective burst obscured the center. Scatterometer data that
clipped the system on the east side also showed winds near tropical
storm intensity. The NOAA aircraft flew through the system shortly
thereafter, and found the system had indeed formed a well-defined
center, with 950-mb flight level winds of 51 kt just to the
northeast of the center. All this information confirms that
Tropical Storm Franklin has formed this afternoon, with an initial
intensity set at 40 kt.

The initial motion is off to the west-northwest at 290/12 kt. Over 
the next 24 hours this general motion should continue while the 
system remains steered by a narrow mid-level ridge. Thereafter, a 
large mid-ocean trough over the western Atlantic will produce a 
pronounced weakness in this ridging, likely causing the tropical 
storm to make a sharp turn northward, bringing the storm near or 
over the large island of Hispaniola in about 48-60 h. Afterwards, 
another mid-latitude trough is forecast to amplify southward, 
maintaining this weakness, and resulting in Franklin turning 
northeastward towards the end of the forecast period. There is a 
decent amount of spread in the track guidance, related to just when 
Franklin will make the initial northward turn. For this initial 
forecast, the NHC track forecast will stick close to the track 
consensus TVCN, which favors a track in between the latest ECMWF and 
GFS solutions, favoring the GFS a bit more.

Intensity wise, Franklin may have to deal with a bit of westerly
wind shear in the short-term, limiting more robust intensification
early on. However, this shear drops off as the system makes its turn
northward towards Hispaniola a bit more intensification is shown
with a 55-kt intensity peak as Franklin approaches the coast. The
intensity forecast then is complicated by the fact that Franklin
will likely pass near or over the island sometime in the 2-3 day
time period, and some weakening is shown during this time.
However, the forecast environment after the system re-emerges into
the Western Atlantic looks mostly favorable, with reintensification
likely as long as the system is not too disrupted by the higher
terrain of Hispaniola. The NHC intensity forecast is in good
agreement with the consensus aids, and lies closest to the HFIP
corrected consensus approach through the forecast period.

Based on the current track forecast, a tropical storm watch has
been issued for the entire southern coastline of Haiti and the
Dominican Republic.


KEY MESSAGES:

1. Franklin is forecast to approach Hispaniola late on Tuesday and
move across the island on Wednesday as a tropical storm, bringing a
risk of flooding from heavy rainfall, strong winds, and dangerous
waves along the coast.

2. Heavy rainfall from Franklin is expected across portions of
Puerto Rico and Hispaniola through the middle of the week. The heavy
rainfall may produce areas of flash and urban flooding as well as
river rises and mudslides. Across Hispaniola, significant and
potentially life-threatening flash flooding is possible Tuesday into
Wednesday.


FORECAST POSITIONS AND MAX WINDS

INIT  20/2100Z 14.6N  67.1W   40 KT  45 MPH
 12H  21/0600Z 15.0N  68.9W   45 KT  50 MPH
 24H  21/1800Z 15.4N  70.7W   45 KT  50 MPH
 36H  22/0600Z 15.8N  71.5W   50 KT  60 MPH
 48H  22/1800Z 17.2N  71.5W   55 KT  65 MPH
 60H  23/0600Z 19.1N  71.1W   50 KT  60 MPH...INLAND
 72H  23/1800Z 21.0N  70.6W   55 KT  65 MPH...OVER WATER
 96H  24/1800Z 23.9N  67.5W   65 KT  75 MPH
120H  25/1800Z 25.4N  65.0W   75 KT  85 MPH

$$
Forecaster Papin

[Witness Protection Program]

Dang, how long has it been Franklin?  I assume a lot of lighting involved?  The key for me is keeping this turkey away from Houston.

[Windspeed]

Dang, how long has it been Franklin?  I assume a lot of lighting involved?  The key for me is keeping this turkey away from Houston.

Just became Franklin, and you must be confusing this system (topic) with the Gulf of Mexico system. Franklin will not be a threat to the Gulf but could pose some interaction with the Mid-Atlantic to New England depending on how modeling evolves and trough vs western Atlantic ridging interaction.

[dmillz25]

Yep looks to affect my home country of DR but they could handle it

[Floydbuster]

Here's a video update on Franklin...and Hilary...and 91L....and TD-6...and Emily....and the wave off Africa...
https://www.youtube.com/watch?v=u4WHe9sAbR8

[olafminesaw]

Weenie alert issued for New England. Preposterous GFS runs possibly posted on Twitter over the coming days.