CrazyC83's Florence Forecast #20 - Surprise! She ain't dead!

[CrazyC83]

Hurricane Florence Amended Prediction #12A

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

Florence is currently undergoing rapid intensification and the intensity suddenly increased as Recon found at least 96kt flight level winds. Since I don't think that will be the highest they find, the initial intensity is increased to 90 kt. Nonetheless, the eye is not fully closed at this point, suggesting it is not at full strength.

The track is unchanged, but the intensities will all be increased. Florence should be stronger than Fabian over Bermuda, and stronger than Juan when it reaches Atlantic Canada. I think it will reach Category 4 for a while as well.

No graphics are being issued on this update.

Current - 29.2/66.0 - 971mb - 105mph
12 hrs - 31.3/66.6 - 955mb - 125mph - SW of Bermuda
24 hrs - 33.8/66.3 - 943mb - 135mph - NW of Bermuda
36 hrs - 37.2/64.4 - 947mb - 125mph
48 hrs - 40.7/61.0 - 949mb - 125mph
60 hrs - 44.6/57.6 - 951mb - 115mph
72 hrs - 47.3/53.2 - 952mb - 110mph - Inland, Transitioning
96 hrs - 51.1/45.4 - 963mb - 85mph - Extratropical
120 hrs - 54.8/35.2 - 973mb - 70mph - Extratropical

[Bane]

i have a question. why are you setting wind speed 15 mph higher than the hurricane center, especially considering they have the data to back up 90 mph. you should use the same reduction rate they use to actually give a more accurate account of florence's current strength.

also, why do you think she will ever reach 135 mph? you are much higher here than the hurricane center.

[CrazyC83]

i have a question. why are you setting wind speed 15 mph higher than the hurricane center, especially considering they have the data to back up 90 mph. you should use the same reduction rate they use to actually give a more accurate account of florence's current strength.

also, why do you think she will ever reach 135 mph? you are much higher here than the hurricane center.

I was using the 90% reduction - proper for the level they were at, which brought it up to 85 kt - and also assumed the highest winds were not sampled.

I am going to write a new update shortly.

[CrazyC83]

Hurricane Florence Prediction #13

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

Florence continues to strengthen slowly this evening. The latest data shows the pressure is down a touch and the structure of Florence has become a bit tighter since the last update. The intensity is being held at 90 kt as it remains possible that the winds have not changed much in the last few hours.

Continued strengthening is expected for the next 24 hours or so, and Florence could very well top out as a major hurricane before reaching Bermuda and certainly before all is said and done. I am skeptical about the weakening that the NHC is suggesting after that; recent storms such as Alex, Fabian, Juan, Karl and Kate did not really lose as much strength as expected in the mid-latitudes. Hence I continue to predict a Category 2 impact on Atlantic Canada. The extratropical transition can enhance the windfield.

The cone remains a 3-day cone. If the intensity changes dramatically in the flight, an amended forecast may be issued.



Current - 30.1/66.2 - 971mb - 105mph
12 hrs - 32.1/66.4 - 960mb - 115mph - Near Bermuda
24 hrs - 34.3/66.2 - 951mb - 125mph
36 hrs - 37.3/64.7 - 948mb - 125mph
48 hrs - 39.9/62.2 - 950mb - 120mph
60 hrs - 44.7/57.4 - 955mb - 105mph - Entering ET
72 hrs - 48.2/52.0 - 963mb - 85mph - Extratropical
96 hrs - 52.6/42.4 - 967mb - 75mph - Extratropical
120 hrs - 54.7/31.3 - 975mb - 70mph - Extratropical

[Bane]

hurricane center still has this at 90 mph. i think you should consider their data in determining current wind speed. you're doing a fine job, other than that.

[Bane]

winds remain 90 mph in the official forecast. you should consider coming in line with them on intensity.

[CrazyC83]

Hurricane Florence Prediction #14

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

Florence changed course somewhat and wobbled a bit more eastward this evening, with a slight deterioration in its organization. The initial intensity is brought down a bit to 85 kt, but that is a fairly uncertain estimate based on the satellite images as no Recon has flown recently.

Nonetheless, the eastward jog will bring stronger winds to Bermuda as the eyewall will be much closer. It is still possible that Florence could strengthen before reaching Bermuda, although only modest strengthening is forecasted here. The warm water extends well farther north, and the extratropical transition should be a slow one over the north Atlantic.

The cone remains a 3-day cone. If the intensity changes dramatically in the flight, an amended forecast may be issued.



Current - 31.0/66.1 - 973mb - 100mph
12 hrs - 32.6/65.9 - 963mb - 110mph - Near Bermuda
24 hrs - 35.1/65.0 - 955mb - 120mph
36 hrs - 37.6/63.4 - 954mb - 120mph
48 hrs - 40.7/60.8 - 954mb - 115mph
60 hrs - 44.6/56.9 - 958mb - 105mph - Transition to Extratropical
72 hrs - 48.4/50.4 - 966mb - 85mph - Extratropical
96 hrs - 51.7/40.6 - 970mb - 75mph - Extratropical
120 hrs - 53.8/28.8 - 977mb - 65mph - Extratropical

[mtm4319]

I think it's fine to make your own intensity estimates (as long as they aren't ridiculously off), but using the pressure from NHC advisories is the best thing to do. They have the recon, and that's by far the most accurate way to estimate pressures.

[CrazyC83]

I think it's fine to make your own intensity estimates (as long as they aren't ridiculously off), but using the pressure from NHC advisories is the best thing to do. They have the recon, and that's by far the most accurate way to estimate pressures.

That's true. In some cases though it may have changed a bit like here as no Recon has gone through in 4 hours.

Most of us were putting Florence at 85 kt when the NHC had her at 80 kt due to the flight-level wind report that was interpreted differently. (I went for 90 kt thinking that the highest were not sampled)

[Bane]

i have no problem with someone trying to create their own intensity forecast either, but staying 15 mph higher than the official forecast seems unreasonable, especially when satellite images suggest the nhc's intensity is accurate.

i would suggest you never go with a higher wind speed because you think the whole system hasn't been sampled. you can always send out another forecast after the system has been completely sampled.

always err on the side on conservative estimates.

[CrazyC83]

Hurricane Florence Prediction #15

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

After weakening in my sleep, Florence regained a much better shape this morning. The pressure barely changed and hurricane force winds were reported in Bermuda. The eyewall did not hit Bermuda, so the winds were likely still stronger. As a result, the initial intensity is held at 85 kt (it would have been increased from early morning estimates if I made them).

The track has been moved a bit to the right, sparing Newfoundland a direct landfall at this point - but that can change. It should also transition into a large extratropical storm within 72 hours as it passes by Atlantic Canada.

The cone remains a 3-day cone. If the intensity changes dramatically in the flight, an amended forecast may be issued.



Current - 32.9/65.6 - 973mb - 100mph
12 hrs - 35.4/64.2 - 966mb - 110mph
24 hrs - 38.1/62.2 - 968mb - 105mph
36 hrs - 41.0/59.8 - 970mb - 100mph
48 hrs - 43.6/56.4 - 974mb - 90mph - Transition to Extratropical
60 hrs - 46.0/52.6 - 975mb - 85mph - Extratropical
72 hrs - 48.1/47.7 - 975mb - 80mph - Extratropical
96 hrs - 54.2/35.7 - 978mb - 70mph - Extratropical
120 hrs - 56.5/25.1 - 981mb - 60mph - Extratropical

[CrazyC83]

Hurricane Florence Prediction #16

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

While satellite estimates for Florence suggest considerable weakening, the reports from Bermuda have suggested that Florence remains a strong storm and the pressure has not budged. Because of those factors, I am leaving the initial intensity at 85 kt.

Little change in its intensity are expected for the next little while, followed by a slow weakening as it approaches Newfoundland over cooler waters. Due to the experience in recent storms with extratropical interaction, te forecast intensity remains higher than the NHC prediction for the next few days.

The cone remains a 3-day cone.



Current - 34.4/64.8 - 972mb - 100mph
12 hrs - 37.2/63.3 - 973mb - 105mph
24 hrs - 40.1/60.6 - 973mb - 100mph
36 hrs - 43.4/57.4 - 975mb - 90mph
48 hrs - 46.4/53.8 - 975mb - 85mph - Transition to Extratropical
60 hrs - 48.8/49.7 - 977mb - 75mph - Extratropical
72 hrs - 51.3/44.5 - 981mb - 65mph - Extratropical
96 hrs - 54.0/33.6 - 983mb - 60mph - Extratropical
120 hrs - Absorbed by another low

[CrazyC83]

Hurricane Florence Prediction #17

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

The structure of Hurricane Florence has deteriorated slightly this evening in the increasing shear and gradually cooler waters of the north Atlantic. The first signs of extratropical transition are taking place. However, the pressure has barely moved and there is some skeptism about possible underestimation in the mid-latitudes. The initial intensity is lowered only to 80 kt as a result.

Slight weakening is on the horizon in my view before reaching Newfoundland. That being said, I do believe that the redevelopment into an extratropical cyclone may actually deepen Florence, although the wind speeds would not be reflected in such. It may take on a subtropical character for a while as well.

The cone remains a 3-day cone.



Current - 35.8/63.9 - 974mb - 90mph
12 hrs - 39.8/60.2 - 978mb - 85mph
24 hrs - 42.8/56.9 - 978mb - 80mph
36 hrs - 46.8/52.9 - 973mb - 75mph - Extratropical
48 hrs - 49.7/48.7 - 976mb - 70mph - Extratropical
60 hrs - 51.9/42.8 - 979mb - 65mph - Extratropical
72 hrs - 52.8/36.7 - 982mb - 65mph - Extratropical
96 hrs - Absorbed by another low

[CrazyC83]

Hurricane Florence Prediction #18

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

Hurricane Florence is starting to become extratropical, but retains a well-defined eye. Due to the well-defined eye and nature of the storm plus past experience with transitioning storms, I remain somewhat skeptical of the NHC's estimates. As a result, I will put the initial intensity at 75 kt.

Little change in strength is expected before becoming fully extratropical. That means that SE Newfoundland could see hurricane conditions. Afterward, it should remain a powerful extratropical storm before being absorbed by a second system around 72 hours.

The cone has been removed due to its large size and nearly certain track plus its increasingly extratropical nature.



Current - 38.2/61.2 - 982mb - 85mph - Entering ET
12 hrs - 42.6/57.9 - 980mb - 85mph - Transition to Extratropical
24 hrs - 46.3/53.8 - 980mb - 80mph - Extratropical
36 hrs - 49.6/48.0 - 979mb - 70mph - Extratropical
48 hrs - 52.1/42.2 - 982mb - 65mph - Extratropical
60 hrs - 53.7/35.0 - 985mb - 60mph - Extratropical
72 hrs - Absorbed by another low

[CrazyC83]

Hurricane Florence Prediction #19

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

Hurricane Florence is quickly becoming extratropical, although some deep convection does remain. The wind field is enlarging as typically takes places in extratropical transition. Nonetheless, I still think there is enough left to keep it somewhat tropical for now. The initial intensity is set at 70 kt.

Little change in strength is expected in the near future until well after fully extratropical - which should take place tonight. I still see a hurricane-strength storm when it reaches Newfoundland.

The cone has been removed due to its large size and nearly certain track plus its increasingly extratropical nature.



Current - 39.6/59.5 - 982mb - 80mph - Transition to Extratropical
12 hrs - 42.7/56.3 - 982mb - 80mph - Extratropical
24 hrs - 45.7/52.9 - 982mb - 80mph - Extratropical
36 hrs - 48.3/48.5 - 984mb - 70mph - Extratropical
48 hrs - 51.3/42.4 - 984mb - 60mph - Extratropical
60 hrs - 52.9/35.0 - 986mb - 50mph - Extratropical
72 hrs - Absorbed by another low

[CrazyC83]

Hurricane Florence Prediction #20

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

As I thought it was extratropical, I had issued the final advisory...but some new convection has fired up meaning it is not fully extratropical yet! As a result, I can't let this system go! I am maintaining a 70 kt initial intensity.

Will it stay tropical for much longer? I doubt it, but who knows. Regardless, near-hurricane conditions are likely to occur soon over Newfoundland, and they should have prepared for a Category 1 hurricane. After that, the extratropical system should ultimately merge with another system and track towards northern Europe as a full entity.

Most likely, this indeed will be the final advisory - unless it is still a real tropical system tomorrow morning.



Current - 41.4/58.1 - 979mb - 80mph - Transition to Extratropical
12 hrs - 44.6/55.1 - 977mb - 80mph - Extratropical
24 hrs - 47.9/50.0 - 977mb - 75mph - Extratropical
36 hrs - 51.6/44.7 - 980mb - 65mph - Extratropical
48 hrs - 54.1/42.8 - 983mb - 50mph - Extratropical
60 hrs - Absorbed by another low