TC Bertha

[KWT]

Yeah they may hold it at 90kts even given Sat.estimates are only that high right now, though IMO its probably major now...cycloneye, thats sooo impressive for July, you really can't miss the stadium effect, wish we had recon there now so bad!

['CaneFreak]

This is not a cat 3 hurricane. It is just not. The cloud tops are not cold enough around the center for this to be a cat 3 hurricane. If I were to guess at the intensity, I would say this is a 95 knot Category 2 based on the intensity estimates I have seen posted. Oh and let me stress this....this hurricane will be going out to sea...the US can breathe a sigh of relief but our friends in Bermuda need to be preparing NOW because this thing could wreak havoc on their little island.

I did not believe it was stronger than Cat 2 status until I reviewed the very latest data over the past few minutes. I agree that the strongest winds were likely not mixing to the surface earlier, but that may be changing now.

It may be a cat 3 NOW but it wont be on the advisory because they have already written it.

[RL3AO]

This is not a cat 3 hurricane. It is just not. The cloud tops are not cold enough around the center for this to be a cat 3 hurricane. If I were to guess at the intensity, I would say this is a 95 knot Category 2 based on the intensity estimates I have seen posted. Oh and let me stress this....this hurricane will be going out to sea...the US can breathe a sigh of relief but our friends in Bermuda need to be preparing NOW because this thing could wreak havoc on their little island.

You don't know how strong it is. I don't know how strong it is. The national hurricane center doesn't know how strong it is. It could be 70 kts or 120kts, or somewhere inbetween.

Your right. I don't know how strong it is. BUT, I do know this....as many major hurricanes as I have seen in my life, I have NEVER seen a category 3 hurricane with -60C cloud tops surrounding the center. NEVER. There needs to be some -80s for me to believe it is a cat 3.

So -60C = 95kts, and -80C =100kts? The 5kt difference is cloud top temps?

[WmE]

This is not a cat 3 hurricane. It is just not. The cloud tops are not cold enough around the center for this to be a cat 3 hurricane. If I were to guess at the intensity, I would say this is a 95 knot Category 2 based on the intensity estimates I have seen posted. Oh and let me stress this....this hurricane will be going out to sea...the US can breathe a sigh of relief but our friends in Bermuda need to be preparing NOW because this thing could wreak havoc on their little island.

You don't know how strong it is. I don't know how strong it is. The national hurricane center doesn't know how strong it is. It could be 70 kts or 120kts, or somewhere inbetween.

Your right. I don't know how strong it is. BUT, I do know this....as many major hurricanes as I have seen in my life, I have NEVER seen a category 3 hurricane with -60C cloud tops surrounding the center. NEVER. There needs to be some -80s for me to believe it is a cat 3.

Are you sure? I remember Gordon of 2006 being a major with just -60°C tops, I could be wrong though.

['CaneFreak]

"So -60C = 95kts, and -80C =100kts? The 5kt difference is cloud top temps?"

NOOOOOOOOOO...Its all about friction and updrafts and downdrafts and the amount of wind that actually makes it to the surface. -60C cloudtops dont mean a certain windspeed. -80 cloudtops don't mean a wind speed. Trust me. Just wait for the advisory. If this is a category 3 hurricane I will be VERY SURPRISED.

[KWT]

If I recall Dean 07 was a cat-5 (1st time round) with only minimal amounts of red on the IR, so its possible depending on the heat content present that systems can get strong without much in the way of real deep convection as long as the eye is warm and the structure is good.

[MiamiensisWx]

000
WTNT32 KNHC 072035
TCPAT2
BULLETIN
HURRICANE BERTHA ADVISORY NUMBER 19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008
500 PM AST MON JUL 07 2008

...BERTHA STRENGTHEN TO A MAJOR HURRICANE WITH 115 MPH WINDS...

AT 500 PM AST...2100Z...THE CENTER OF HURRICANE BERTHA WAS LOCATED
NEAR LATITUDE 20.1 NORTH...LONGITUDE 52.1 WEST OR ABOUT 730 MILES...
1175 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS AND ABOUT
1150 MILES...1855 KM...SOUTHEAST OF BERMUDA.

BERTHA IS MOVING TOWARD THE WEST-NORTHWEST NEAR 12 MPH...19 KM/HR.
A GRADUAL TURN TOWARD THE NORTHWEST WITH A DECREASE IN FORWARD SPEED
IS EXPECTED OVER THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 115 MPH...185
KM/HR...WITH HIGHER GUSTS. BERTHA IS NOW A CATEGORY THREE HURRICANE
ON THE SAFFIR-SIMPSON HURRICANE SCALE. FLUCTUATIONS IN INTENSITY
ARE LIKELY DURING THE NEXT DAY OR TWO.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 25 MILES...35 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115
MILES...185 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 948 MB...27.99 INCHES.

REPEATING THE 500 PM AST POSITION...20.1 N...52.1 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 12 MPH. MAXIMUM SUSTAINED WINDS...115
MPH. MINIMUM CENTRAL PRESSURE...948 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 PM AST.

$$
FORECASTER RHOME

MAJOR HURRICANE BERTHA!!!

[cycloneye]

354
WTNT42 KNHC 072035
TCDAT2
HURRICANE BERTHA DISCUSSION NUMBER 19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008
500 PM EDT MON JUL 07 2008

BERTHA'S SATELLITE PRESENTATION HAS CONTINUED TO IMPROVE THIS
AFTERNOON WITH A VERY DISTINCT EYE NOW SURROUNDED BY A RING OF COLD
CLOUD TOPS. SUBJECTIVE DVORAK T NUMBERS WERE UNANIMOUSLY 5.0 BUT
OBJECTIVE NUMBERS HAVE INCREASED TO 6.0 FOR THE PAST 3 HOURS. THIS
SUPPORTS AN INITIAL INTENSITY OF 100 KT MAKING BERTHA A MAJOR
CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE.
BERTHA'S INTENSIFICATION TO MAJOR HURRICANE TODAY HIGHLIGHTS THE
DIFFICULTIES OF FORECASTING RAPID INTENSITY CHANGES. IN THE
SHORT-TERM...SHEAR IS EXPECTED TO BE LOW AND THE INTENSITY WILL BE
PRIMARILY CONTROLLED BY EYEWALL CYCLES. AS A RESULT...SOME
FLUCTUATIONS IN INTENSITY ARE LIKELY. IN A DAY OR TWO...THE GFS
MODEL STILL INDICATES INCREASING SHEAR. THE SHIPS AND LGEM
STATISTICAL MODELS...WHICH BASE THEIR SHEAR ESTIMATES FROM THE
GFS...SHOW WEAKENING BEYOND 24 HOURS AND SO DOES THE OFFICIAL
FORECAST.

BERTHA HAS BEEN MOVING MORE TOWARDS THE NORTHWEST DURING THE LAST
COUPLE OF HOURS WITH A REDUCTION IN FORWARD SPEED...BOTH INDICATIONS
THAT THE HURRICANE HAS REACHED THE MUCH-ANTICIPATED WEAKNESS IN THE
RIDGE. SINCE BERTHA COULD BE WOBBLING...THE INITIAL MOTION
ESTIMATE BASED ON A 12 HOUR AVERAGE IS 300/10. TRACK GUIDANCE
REMAINS IN GOOD AGREEMENT ON A GRADUAL NORTHWARD TURN DURING THE
NEXT 2-3 DAYS. THEREAFTER...GLOBAL MODELS SUGGEST THAT THE
STEERING CURRENTS COULD BECOME WEAK LEADING TO INCREASED UNCERTAINTY
IN THE TRACK FORECAST. EVEN THOUGH THE OFFICIAL FORECAST IS
SHIFTED A LITTLE TO THE EAST...IT IS STILL WAY TOO SOON TO
DETERMINE WHETHER OR NOT BERTHA WILL AFFECT BERMUDA.


FORECAST POSITIONS AND MAX WINDS

INITIAL 07/2100Z 20.1N 52.1W 100 KT
12HR VT 08/0600Z 20.8N 53.5W 100 KT
24HR VT 08/1800Z 21.7N 55.4W 95 KT
36HR VT 09/0600Z 22.9N 57.3W 90 KT
48HR VT 09/1800Z 24.0N 59.0W 85 KT
72HR VT 10/1800Z 26.5N 61.5W 80 KT
96HR VT 11/1800Z 29.0N 62.5W 75 KT
120HR VT 12/1800Z 31.5N 62.5W 75 KT

$$
FORECASTER RHOME

['CaneFreak]

I will bite my tongue. They did upgrade it. I can't believe it. The overly conservative NHC did upgrade it. WOW. SHOCKED AND SPEECHLESS.

[vegastar]

This is not a cat 3 hurricane. It is just not. The cloud tops are not cold enough around the center for this to be a cat 3 hurricane. If I were to guess at the intensity, I would say this is a 95 knot Category 2 based on the intensity estimates I have seen posted. Oh and let me stress this....this hurricane will be going out to sea...the US can breathe a sigh of relief but our friends in Bermuda need to be preparing NOW because this thing could wreak havoc on their little island.

You don't know how strong it is. I don't know how strong it is. The national hurricane center doesn't know how strong it is. It could be 70 kts or 120kts, or somewhere inbetween.

Your right. I don't know how strong it is. BUT, I do know this....as many major hurricanes as I have seen in my life, I have NEVER seen a category 3 hurricane with -60C cloud tops surrounding the center. NEVER. There needs to be some -80s for me to believe it is a cat 3.

2007 Hurricane Flossie had 120kt and only -60ºC:

http://www.nrlmry.navy.mil/tc-bin/tc_display.cgi?BASIN=EPAC&STORM_NAME=09E.FLOSSIE&STATUS=inactive&ACTION=Latest_Photos&ACTIVES=None&MOSAIC_SCALE=20&PHOT=yes&ATCF_BASIN=ep&CGI=TC&AGE=Prev&ARCHIVE=all&SIZE=full&NAV=tc&YR=07&ATCF_YR=2007&YEAR=2007&ATCF_FILE=/data/www/atcf_web/public_html/image_archives/2007/ep092007.07081700.gif&MO=AUG&CURRENT=20070813.1730.goes11.x.ir1km.09EFLOSSIE.120kts-957mb-146N-1489W.100pc.jpg&CURRENT_ATCF=ep092007.07081700.gif&ATCF_NAME=ep092007&ATCF_DIR=/data/www/atcf_web/public_html/image_archives/2007&STYLE=frames&USE_THIS_DIR=/TC/tc07/EPAC/09E.FLOSSIE/CloudSat&DIR=/TC/tc07/EPAC/09E.FLOSSIE/ir/geo/1km&TYPE=geo&PROD=ir&SUB_PROD=1km

[MiamiensisWx]

I will bite my tongue. They did upgrade it. I can't believe it. The overly conservative NHC did upgrade it. WOW. SHOCKED AND SPEECHLESS.

Bill Read talks!!!

[Decomdoug]

Nice banding is forming, starting to assume a classic "buzzsaw" shape. Can anyone estimate the diameter of the wind field?

[KWT]

Wow Major Hurricane Bertha...its like "anything 96 Bertha does I can do better" with this system I swear!

Still amazing to have a major hurricane this far east in July, it would be an impressive hurricane even in the main Cape Verde season.

[RL3AO]

"So -60C = 95kts, and -80C =100kts? The 5kt difference is cloud top temps?"

NOOOOOOOOOO...Its all about friction and updrafts and downdrafts and the amount of wind that actually makes it to the surface. -60C cloudtops dont mean a certain windspeed. -80 cloudtops don't mean a wind speed. Trust me. Just wait for the advisory. If this is a category 3 hurricane I will be VERY SURPRISED.

I'm not going after you. Its just one of the things that gets me going. That major changes have to happen to reach a magical barrier. 100kts is one of those barriers. Its just your first post you were so defiant that it wasn't a cat 3...but you said its 95kts. Its hard to explain what I mean. Its only a 5kt difference. I mean you are certain its not cat 3, but you seem sure its 95kts. Do you see what I'm getting at? Don't take any thing from it. Its just one of my pet peeves. That something magical happens between 60kts and 65kts. In reality it doesn't. The difference between 60 and 65 is the same as 55 and 60...but a magical word happens at 65 so its a big deal.

</rant>

[WmE]

948mbar. Wow that's low for a low end Cat3.

[ekal]

If Bertha strikes Bermuda, it will join Alice (1973) as the second tropical cyclone in recorded history to affect Bermuda in July. This storm is a rarity in many ways.

Bertha looks absolutely stunning this afternoon.

[Scorpion]

Pretty big drop in pressure too.. wasn't it 975 mb at 11?

[RL3AO]

948mbar. Wow that's low for a low end Cat3.

Yeah it does. I remember that Felix was 929 as a cat 5.

[Stratosphere747]

Keep in mind that these are nothing but estimates. I'd be much more impressed with actual observations from recon.

[cheezyWXguy]

This is not a cat 3 hurricane. It is just not. The cloud tops are not cold enough around the center for this to be a cat 3 hurricane. If I were to guess at the intensity, I would say this is a 95 knot Category 2 based on the intensity estimates I have seen posted. Oh and let me stress this....this hurricane will be going out to sea...the US can breathe a sigh of relief but our friends in Bermuda need to be preparing NOW because this thing could wreak havoc on their little island.

At this latitude, with these water temps, bright reds are not as common to major hurricanes...sure this likely becomes the reason why it would not eventually become a cat 4 or 5, but you must look at how well organized the system is. And its certainly organized well enough to be a major.