Hurricane Francine

[Radtechwxman]

Looks like we are getting decent pressure drops again. Probably will see a hurricane later this morning or early afternoon. 

[wthrmn654]

Current Intensity Analysis
 

                     UW - CIMSS                     
              ADVANCED DVORAK TECHNIQUE       
                    ADT-Version 9.1                
         Tropical Cyclone Intensity Algorithm       

             ----- Current Analysis ----- 
     Date :  10 SEP 2024    Time :   121020 UTC
      Lat :   24:41:55 N     Lon :   96:04:15 W

     
                CI# /Pressure/ Vmax
                2.3 /1001.6mb/ 33.0kt

     
             Final T#  Adj T#  Raw T# 
                2.2     2.6     2.7

 Center Temp : -12.7C    Cloud Region Temp : -47.5C

 Scene Type : CURVED BAND with 0.62 ARC in LT GRAY 

 Subtropical Adjustment : OFF 

 Extratropical Adjustment : OFF 

 Positioning Method : FORECAST INTERPOLATION 

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

 Tno/CI Rules : Constraint Limits : 0.5T/hour
                   Weakening Flag : ON    
           Rapid Dissipation Flag : OFF   

 C/K/Z MSLP Estimate Inputs :
  - Average 34 knot radii :   92nmi
  - Environmental MSLP    : 1010mb

 Satellite Name :  GOES16 
 Satellite Viewing Angle : 37.1 degrees

[wthrmn654]

Lower level water vapor 

Mid level water vapor

Upper level water vapor 

(The first 2 maybe backwards just fyi)

[CoastalWx]

It need to get rid of that blob of convection to the NE and work out that dry air. There might be a small window for it to really pick up steam. The eastward ticks are sort of interesting for NoLa.

[wthrmn654]

 

[BoulderWX]

49 minutes ago, 40/70 Benchmark said:

I don't think its going to become as strong as some were speculating. Should still be a hurricane, though. The operative word in my statement was relative.

Almost all prognostications have kept this a cat 1, around 85mph. I still think it has a good shot of becoming a hurricane which would be in line with the expectation. Could be wrong, but if it reaches hurricane status it’s not a bust. 
 

just because some people speculate, doesn’t mean that’s what the official forecast was. And we all know model guidance varies widely with every storm. Most topped it out as a cat 2 and I didn’t see one official forecast going to cat 2. Highest was 100, which may end up too high, but again, not by much. 

[olafminesaw]

9 minutes ago, CoastalWx said:

It need to get rid of that blob of convection to the NE and work out that dry air. There might be a small window for it to really pick up steam. The eastward ticks are sort of interesting for NoLa.

Also gives it more time over water, and may even strengthen somewhat over the Bayou

[thunderbolt]

36 minutes ago, 40/70 Benchmark said:

First of all, many were speculating on a 3 and some guidance was even hinting at 4. Secondly, I think cat 2 is a reach at this point. I think maybe 100mph is the ceiling, which jives with the NHC stating that their 100mph forecast was at the high end of guidance.

Fair assessment, I still believe category two is still within reach which is I believe 95  or better, but just once again, my own thoughts

[wthrmn654]

25 minutes ago, BoulderWX said:

Almost all prognostications have kept this a cat 1, around 85mph. I still think it has a good shot of becoming a hurricane which would be in line with the expectation. Could be wrong, but if it reaches hurricane status it’s not a bust. 
 

just because some people speculate, doesn’t mean that’s what the official forecast was. And we all know model guidance varies widely with every storm. Most topped it out as a cat 2 and I didn’t see one official forecast going to cat 2. Highest was 100, which may end up too high, but again, not by much. 

I think What he's saying is,  the  cat 1 / cat 2 with a couple cat 3, estimates that we saw yesterday on some models at one point were over done. If it's a cat 1 borderline cat 2 that's reasonable, as of this morning... 

[40/70 Benchmark]

4 minutes ago, wthrmn654 said:

I think What he's saying is,  the  cat 1 / cat 2 with a couple cat 3, estimates that we saw yesterday on some models at one point were over done. If it's a cat 1 borderline cat 2 that's reasonable, as of this morning... 

Yea, I didn't think it was that difficult to grasp. 

[NorthHillsWx]

Outside of the “weird” apparent eyewall development yesterday, this storm has panned out almost exactly as expected. It’s taken a while for the broad circulation to tighten and that appears to be happening this morning. I’d expect steady strengthening until the shear increases towards landfall, with weakening whenever that occurs. A turn to the NE may limit the shear due to a more conducive vector but seeing up to 30 kts of shear, with dry continental air, screams a half a cane landfall. I’m still sticking to my 80-90 mph max and landfall likely near that

[40/70 Benchmark]

3 minutes ago, NorthHillsWx said:

Outside of the “weird” apparent eyewall development yesterday, this storm has panned out almost exactly as expected. It’s taken a while for the broad circulation to tighten and that appears to be happening this morning. I’d expect steady strengthening until the shear increases towards landfall, with weakening whenever that occurs. A turn to the NE may limit the shear due to a more conducive vector but seeing up to 30 kts of shear, with dry continental air, screams a half a cane landfall. I’m still sticking to my 80-90 mph max and landfall likely near that

In terms of the consensus, I agree...this is why I qualified my statement with the term "relative".....all that was meant was the window for higher end that appeared to be opening a bit yesterday has closed.

[40/70 Benchmark]

1 hour ago, CoastalWx said:

It need to get rid of that blob of convection to the NE and work out that dry air. There might be a small window for it to really pick up steam. The eastward ticks are sort of interesting for NoLa.

I think the best window for intensification will be overnight tonight, as it gets a bit further from mainland MX and perhaps passess over an eddy of very high TCHP before the more hostile conditions set in tomorrow.

[40/70 Benchmark]

I think it looks okay for a TS nearing cane strength....not great. 

[wthrmn654]

The only question or possibly concern is: the whole fully separation of the 2 big cloud masses that's not showing right now and is that dry air north of or slightly north west of the center to? If it is will that be drawn into it later on? 

 

 

[40/70 Benchmark]

1 minute ago, wthrmn654 said:

The only question or possibly concern is: the whole fully separation of the 2 big cloud masses that's not showing right now and is that dry air north of or slightly north west of the center to? If it is will that be drawn into it later on? 

 

 

That other blob is a non-starter for any RI....take that clear off of the table.

[wthrmn654]

Just now, 40/70 Benchmark said:

That other blob is a non-starter for any RI....take that clear off of the table.

I was kinda assuming that since it become less joined. 

 

[wthrmn654]

Not the best shear maps cause it's not really showing the storm well, will get better one.

Will be interesting to see how she does plowing north east. 

[40/70 Benchmark]

1 minute ago, wthrmn654 said:

Not the best shear maps cause it's not really showing the storm well, will get better one.

Will be interesting to see how she does plowing north east. 

I think that tells you all you ned to know about the degradation of the envt. on approach to the coast tomorrow.

[wthrmn654]

Upper divergence

Lower convergence

[Seminole]

2 minutes ago, 40/70 Benchmark said:

I think that tells you all you ned to know about the degradation of the envt. on approach to the coast tomorrow.

A picture is worth a thousand words. That environment is very hostile tomorrow. I would not be surprised if a tornado watch is issued for areas east of landfall. This setup has all the makings for tornadic activity in the outer bands.  

[wthrmn654]

[olafminesaw]

3 minutes ago, wthrmn654 said:

Upper divergence

Lower convergence

A well ventilated blob! I wonder if this feature imparts a bit of a Fujiwara effect and pulls Francine a little more East.

[salbers]

Here is James Van Fleet's discussion: https://www.linkedin.com/feed/update/urn:li:activity:7239270198455783424/

I'll suggest a central pressure of 970-975mb. Perhaps that's close to a category 2.

[RU848789]

3 hours ago, CurlyHeadBarrett said:

Florence?

[smokeybandit]

Latest NHC cone has a notable jump east for landfall.

[USCG RS]

New Orleans should definitely keep a very close eye on this storm. 

The circulation is rather broad, however, if it were to find a way to tighten, this has the potentially to ramp up rather quickly. Outlier solution in this scenario, but one that should be watched for the next 24 or so hours. 

Of course, if it finds a way to tighten up, this could also spare most of New Orleans to the West. Just something to keep an eye on. 

[RU848789]

17 minutes ago, smokeybandit said:

Latest NHC cone has a notable jump east for landfall.

Yep, that's about a 40 mile shift east, which is pretty significant, especially for New Orleans, if any additional shifts east occur.  It's also interesting to note the bolded part below from the NHC discussion, wherein they show that the forecasted peak intensity of the storm hasn't really changed from the 85 knot/100 mph forecast from earlier - it's just that the points on the map they choose to display now shows an implied max of 80 knots/90 mph. 

Three things I wish the NHC would do: i) provide a zoomed in map of the landfall area, so one can see more details (and more easily see run to run shifts), which are hard to see when looking at maps that are 2000 miles across, ii) provide a finer continuum of forecast locations/winds, so one doesn't "miss" intensity peaks (or dips) and iii) label the track maps at the points shown with the forecast wind speeds instead of the limited S/H/M labels, which aren't detailed enough.  

Tropical Storm Francine Discussion Number   8
NWS National Hurricane Center Miami FL       AL062024
1000 AM CDT Tue Sep 10 2024

However, there has been an eastward shift of the guidance since the last 
advisory, and thus the new forecast track is also shifted eastward.  
In response to this eastward shift in track and southeastern wind 
radii, the hurricane warning in Louisiana was extended eastward at 
12Z, and this advisory has new tropical storm warnings and watches 
for the coasts of Mississippi and Alabama.

Francine has about 24-30 h to strengthen over warm water before it 
encounters strong shear near the Louisiana coast.  While there is a 
possibility that dry air entrainment could reduce the 
intensification rate, the intensity continues to call for steady to 
rapid strengthening during this time based on the otherwise 
favorable conditions.  While it is not explicitly shown in the 
latest forecast, the cyclone could reach a peak intensity near 85 kt 
between the 24 h point and landfall.  Intensification is expected to 
stop before landfall, and rapid weakening is expected after 
landfall.  The global models show the remnants of Francine 
dissipating after 96 h, and the intensity forecast follows that 
scenario. Overall, the intensity forecast is at the upper edge of 
the intensity guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 24.9N  95.6W   55 KT  65 MPH
 12H  11/0000Z 26.0N  94.8W   65 KT  75 MPH
 24H  11/1200Z 27.8N  93.2W   80 KT  90 MPH
 36H  12/0000Z 29.9N  91.3W   75 KT  85 MPH...INLAND
 48H  12/1200Z 32.2N  90.4W   40 KT  45 MPH...INLAND
 60H  13/0000Z 34.6N  90.1W   30 KT  35 MPH...INLAND
 72H  13/1200Z 35.8N  90.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  14/1200Z 37.0N  90.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  15/1200Z...DISSIPATED

[BoulderWX]

Official forecast shifts east and continues to be progged as a Cat 1 at landfall. Everything seems to be on track intensity wise.  
 

65 mph at last update 

[wthrmn654]

Hurricane hunters saw 990, then 988 them the last 2 passes by 2 planes it raised back up to about 990