NHC discussion at 5 pm in full (deserves own thread)-SCARY!

[rob8303]

VERY Scary. I haven't seen a discussion from NHC like this EVER:

THE ALLEGED EYE OF ISABEL PASSED OVER BUOY 13008 LOCATED AT 15N 38W
BETWEEN 14-15Z. THE BUOY REPORTED 37 KT AND 24 KT NORTHEAST WINDS
...TO THE SOUTH OF ALL THE SATELLITE CENTER POSITIONS. THESE WIND
REPORTS SUGGEST THAT THE ACTUAL CENTER IS FARTHER SOUTH NEAR THE
SOUTHERN PORTION OF THE EYE FEATURE...AS MENTIONED IN THE PREVIOUS
DISCUSSION. DURING THE PAST 6 HOURS...THE EYE FEATURE...OVERALL
CONVECTIVE PATTERN...AND OUTFLOW PATTERN HAVE CONTINUED TO IMPROVE.
THE INITIAL INTENSITY OF 70 KT IS BASED ON SATELLITE INTENSITY
ESTIMATES OF 65 KT FROM TAFB AND SAB...AND 77 KT FROM AFWA.

THE INITIAL MOTION ESTIMATE IS 295/13. THE INITIAL POSITION REMAINS
ABOUT 24 NMI SOUTH OF THE SATELLITE POSITIONS. THE 12Z GLOBAL
MODELS ARE IN EVEN BETTER AGREEMENT NOW ON KEEPING AT LEAST A
MODERATE SUBTROPICAL RIDGE NORTH OF ISABEL ALONG 32N LATITUDE
THROUGHOUT THE FORECAST PERIOD...AND EVEN BUILD IT WESTWARD ACROSS
THE BAHAMAS AND FLORIDA. THIS SHOULD KEEP ISABEL MOVING
WEST-NORTHWESTWARD THROUGH 48-72 HOURS...WITH A GRADUAL WESTWARD
MOTION DEVELOPING AFTER THAT. THE PREVIOUS FORECAST TRACK WAS ONLY
SHIFTED SLIGHTLY NORTHWARD AND SLOWED A LITTLE AFTER 72 HOURS...
WHICH IS CONSISTENT WITH THE GLOBAL MODEL CONSENSUS.

ISABEL CURRENTLY HAS A VERY IMPRESSIVE OUTFLOW PATTERN AND...
UNFORTUNATELY...THE GLOBAL MODELS ARE FORECASTING IT TO BECOME EVEN
BETTER. BY 36-48 HOURS... ALL OF THE GLOBAL MODELS EXCEPT THE UKMET
ARE FORECASTING MORE THAN 50 KT OF OUTFLOW ON THE WEST SIDE OF
ISABEL BEING DRAWN INTO AN UPPER-LEVEL LOW LOCATED JUST NORTHEAST
OF THE LEEWARD ISLANDS. A PATTERN LIKE THAT CAN OFTENTIMES LEAD TO
RAPID OR EXPLOSIVE DEEPENING. THE SHIPS INTENSITY MODEL BRINGS
ISABEL UP TO 97 KT IN 60 HOURS...BUT THE OFFICIAL FORECAST IS A
LITTLE HIGHER SINCE SHIPS WAS LOW/SLOW WITH THE INTENSIFICATION OF
FABIAN. THE INTENSITY WAS LEVELED OFF AFTER 48 HOURS SINCE ISABEL
MAY CROSS A POSSIBLE COLD WAKE LEFT BEHIND BY HURRICANE FABIAN.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 07/2100Z 15.2N 39.1W 70 KT
12HR VT 08/0600Z 15.8N 40.5W 75 KT
24HR VT 08/1800Z 16.5N 42.8W 85 KT
36HR VT 09/0600Z 17.2N 45.2W 95 KT
48HR VT 09/1800Z 18.0N 47.7W 100 KT
72HR VT 10/1800Z 19.0N 52.0W 100 KT
96HR VT 11/1800Z 19.5N 55.5W 100 KT
120HR VT 12/1800Z 19.5N 60.0W 100 KT

[PTrackerLA]

That doesn't sound good for the US, this one has me worried.

[rob8303]

Indeed me too

[charleston_hugo_veteran]

Time to get the hurricane check list out!

[weatherlover427]

Uh oh ... not good at all! I especially don't like these parts:

DURING THE PAST 6 HOURS...THE EYE FEATURE...OVERALL CONVECTIVE PATTERN...AND OUTFLOW PATTERN HAVE CONTINUED TO IMPROVE.


THE 12Z GLOBAL MODELS ARE IN EVEN BETTER AGREEMENT NOW ON KEEPING AT LEAST A
MODERATE SUBTROPICAL RIDGE NORTH OF ISABEL ALONG 32N LATITUDE THROUGHOUT THE FORECAST PERIOD...AND EVEN BUILD IT WESTWARD ACROSS THE BAHAMAS AND FLORIDA.

ISABEL CURRENTLY HAS A VERY IMPRESSIVE OUTFLOW PATTERN AND...UNFORTUNATELY...THE GLOBAL MODELS ARE FORECASTING IT TO BECOME EVEN BETTER.

BY 36-48 HOURS... ALL OF THE GLOBAL MODELS EXCEPT THE UKMET ARE FORECASTING MORE THAN 50 KT OF OUTFLOW ON THE WEST SIDE OF ISABEL BEING DRAWN INTO AN UPPER-LEVEL LOW LOCATED JUST NORTHEAST OF THE LEEWARD ISLANDS.

and the worst one IMO (along with the second one) ...

A PATTERN LIKE THAT CAN OFTENTIMES LEAD TO RAPID OR EXPLOSIVE DEEPENING.

[Stormsfury]

Isabel when the storm becomes a little more properly stacked has every oppotunity to become a major ... this line is quite frightening indeed.

ISABEL CURRENTLY HAS A VERY IMPRESSIVE OUTFLOW PATTERN AND...
UNFORTUNATELY...THE GLOBAL MODELS ARE FORECASTING IT TO BECOME EVEN
BETTER. BY 36-48 HOURS... ALL OF THE GLOBAL MODELS EXCEPT THE UKMET
ARE FORECASTING MORE THAN 50 KT OF OUTFLOW ON THE WEST SIDE OF
ISABEL BEING DRAWN INTO AN UPPER-LEVEL LOW LOCATED JUST NORTHEAST
OF THE LEEWARD ISLANDS. A PATTERN LIKE THAT CAN OFTENTIMES LEAD TO
RAPID OR EXPLOSIVE DEEPENING. THE SHIPS INTENSITY MODEL BRINGS
ISABEL UP TO 97 KT IN 60 HOURS...BUT THE OFFICIAL FORECAST IS A
LITTLE HIGHER SINCE SHIPS WAS LOW/SLOW WITH THE INTENSIFICATION OF
FABIAN. THE INTENSITY WAS LEVELED OFF AFTER 48 HOURS SINCE ISABEL
MAY CROSS A POSSIBLE COLD WAKE LEFT BEHIND BY HURRICANE FABIAN.

[charleston_hugo_veteran]

Let's face it, nothing in this paragraph is good! Let's hope it changes for everyones sake!

[Renata]

Alleged eye.

If the hurricane specialists are alleging then yes ... we ought to be scared.

The "allegation" raises some questions, presumptions, and comments:

(1) We are not dealing with a hurricane but a very mature-looking storm, therefore the eye position is correct;

(2) We are dealing with a hurricane and given that tropical storm force winds extend outward to 90 miles, then it stands to reason that the buoy was was measuring the winds on the outter NE limit and that would put the eye somewhere 1.5 degrees SW of the "alleged" position - so we're talking somewhere in the vicinity of 14.5N 40W

(3) There is no closed circulation and the NW quad is open ... remember an earlier discussion about dry air coming in from the SW and NE?

Comments??

[Derek Ortt]

Lets not get too agitated yet. That discussion came from the most bullish of the forecasters at NHC. I have seen much more urgent than that one.

Also, remember, anything past 3 days is merely an outlook due to the high error margins. So, it is well too early to get into a panick or anything about a possible US landfall

[Thunder44]

I think it is safe to say that Isabel will be a major hurricane. This is time to start talking about another Andrew, Camile, or Hugo.

[Lindaloo]

Camille?

[Josephine96]

Isabel is 1 mean lady.. I think what's left of Fabian and Henri as well as future "Juan" perhaps should all be scared. Not telling what will happen if 1 of them pisses her off

[dixiebreeze]

I'm not panicking Derek, but "explosive deepening" is a term I've not heard before in an NHC discussion this early in development. :o Won't be taking my eyes off Isabel.

[weatherlover427]

After all, she only has 80 MPH winds. 100 kt = 115 MPH, barely a cat 3. I think she could go a LOT higher since they indicated explosive deepening. Looks like she has a lot going for her.

[Derek Ortt]

However, what was not mentioned in that discussion is the fact that ALL guidance weakens the system slightly after 72 hours, probably due to increasing shear and a less favorable CAPE and theta-e

[rob8303]

Derek, you mentioned that Stewart is very bullish. Does this include track as well? Intensity doesn't matter if this storm just swims with the fishes but is Stewart usually predicting CONUS landfalls and is his talk about the ridging correct or is that bullish too? BTW, I know he didn't predict CONUS landfall. I just asked if he's made that mistake in the past.

[Stormsfury]

However, what was not mentioned in that discussion is the fact that ALL guidance weakens the system slightly after 72 hours, probably due to increasing shear and a less favorable CAPE and theta-e

Part of that is from the NHC forecast track takes Isabel over the cool wake left behind from Fabian ...

SF

[Derek Ortt]

He is often the farthest west and is the most aggressive in terms of intensity. There is a slight bias towards stronger systems hitting land areas with him than there are from some of the other forecasters

[Thunder44]

I think he's just tell how he sees it. I also think he consulted with his colleages there before he wrote this advisory. The computer models are unreliable when it comes to intensity of Tropical Cyclones. He's always more specific, not necessarily bullish, but in his details on tropical systems than anybody there. This storm will probably become a major hurricane before 72 hours anyway. And yes Lindloo, this could be a "Camile" if it winds in the GOM.

[wx247]

However, what was not mentioned in that discussion is the fact that ALL guidance weakens the system slightly after 72 hours, probably due to increasing shear and a less favorable CAPE and theta-e

Part of that is from the NHC forecast track takes Isabel over the cool wake left behind from Fabian ...

SF

How long could Isabel be in this area of cooler waters?