ATL: OPHELIA - Remnants - Discussion

[cycloneye]

HURRICANE OPHELIA DISCUSSION NUMBER 31
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011
500 AM AST FRI SEP 30 2011

OPHELIA HAS BEEN RAPIDLY STRENGTHENING DURING THE PAST 12 HOURS
BASED ON AN EYE FEATURE OCCASIONALLY APPARENT ON BOTH INFRARED AND
NIGHT-VISIBLE SATELLITE IMAGES. MICROWAVE IMAGERY INDICATES A
WELL-DEVELOPED AND CLOSED DEEP-LAYER EYE...ALBEIT TILTED SLIGHTLY
TO THE NORTHEAST. A BLEND OF SATELLITE INTENSITY ESTIMATES OF
T5.0/90 KT FROM SAB...T4.5/77 KT FROM TAFB...AND UW-CIMSS AVERAGE
ADT OF T4.7/82 KT IS THE BASIS FOR THE 85-KT ADVISORY INTENSITY.

THE INITIAL MOTION ESTIMATE IS 345/08 KT. THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. OPHELIA IS
CURRENTLY ROUNDING THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE SITUATED ALONG 32N LATITUDE. AN UNSEASONABLY
STRONG MID-TROPOSPHERIC TROUGH IS FORECAST TO DEEPEN AND MOVE
EASTWARD TO THE U.S. EAST COAST BY 48 HOURS...AND WILL ACT TO
ACCELERATE AND LIFT OPHELIA NORTHWARD OVER THE NEXT 72 HOURS. BY
DAYS 3-4...OPHELIA IS FORECAST TO MERGE WITH A FRONTAL SYSTEM AND
BE OVER MUCH COLDER WATER...WHICH WILL RESULT IN THE CYCLONE
BECOMING A STRONG POST-TROPICAL WINTER-TYPE LOW PRESSURE SYSTEM
THAT WILL TURN EASTWARD NEAR THE CANADIAN MARITIMES. THE ONLY
NOTICEABLE CHANGE IN THE MODEL GUIDANCE IS A SOUTHWARD SHIFT IN THE
GUIDANCE TRACKS AFTER 72 HOURS. IN FACT...THE NEW ECMWF RUN BARELY
TAKES OPHELIA AS FAR NORTH AS 45N LATITUDE. THE OFFICIAL FORECAST
TRACK WAS NUDGED SLIGHTLY TO THE LEFT THROUGH 72 HOURS...AND THEN
BROUGHT FARTHER SOUTH IN LINE WITH THE CONSENSUS MODEL...TVCN...BUT
NOT AS FAR SOUTH AS THE ECMWF MODEL TRACK.

THE OUTFLOW OF OPHELIA REMAINS QUITE IMPRESSIVE...EXCEPT THAT THE
WESTERN EDGE OF THE CIRRUS OUTFLOW HAS STARTED TO FLATTEN AND
DISSIPATE AS WESTERLY UPPER-LEVEL WINDS ENCROACH ON THE CYCLONE.
HOWEVER...THE LIGHT TO MODERATE WESTERLY VERTICAL WIND SHEAR THAT
IS CURRENTLY AFFECTING THE CYCLONE IS FORECAST TO TURN MORE FROM
SOUTH-SOUTHWEST BY 36-48 HOURS...WHICH SHOULD ALLOW FOR SOME
ADDITIONAL STRENGTHENING TO OCCUR. ALTHOUGH FURTHER RAPID
STRENGTHENING IS A POSSIBILITY...THE VERTICAL SHEAR IS FORECAST BY
THE SHIPS MODEL TO FLUCTUATE BETWEEN 5 AND 15 KT DURING THE NEXT 48
HOURS...WHICH SHOULD ACT TO KEEP THE EYE TILTED AT TIMES AND LIKELY
DISRUPT THE RAPID INTENSIFICATION PROCESS. AS A RESULT...ONLY
MODEST STRENGTHENING IS FORECAST UNTIL OPHELIA REACHES 22C AND
COLDER SSTS SHORTLY AFTER THE 48-HOUR TIME PERIOD...WHICH IS ALSO
COINCIDENT WITH AN EXPECTED SHARP INCREASE IN THE VERTICAL SHEAR.
THE INTENSITY FORECAST IS SIMILAR TO THE INTENSITY CONSENSUS
MODEL...ICON...THROUGH 72 HOURS...AND THEN LEANS CLOSE TO THE LGEM
MODEL AFTER THAT. IT IS WORTH NOTING THAT SOME OF THE GLOBAL MODELS
ARE NOW HOLDING ON TO OPHELIA AS A ROBUST EXTRATROPICAL LOW
PRESSURE SYSTEM BEYOND 96 HOURS.

FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 22.4N 62.6W 85 KT 100 MPH
12H 30/1800Z 24.2N 63.1W 90 KT 105 MPH
24H 01/0600Z 27.0N 63.4W 90 KT 105 MPH
36H 01/1800Z 30.1N 62.9W 95 KT 110 MPH
48H 02/0600Z 34.6N 61.7W 95 KT 110 MPH
72H 03/0600Z 44.3N 57.0W 65 KT 75 MPH...POST-TROP/EXTRATROP
96H 04/0600Z 51.5N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 05/0600Z...DISSIPATED

$$
FORECASTER STEWART

[Cranica]

That area off the southern East Coast seems to be the golden zone for the year, every storm entering it has strengthened after struggling anywhere else. Weird.

[bexar]

Loop:

[cycloneye]

BULLETIN
HURRICANE OPHELIA INTERMEDIATE ADVISORY NUMBER 31A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011
800 AM AST FRI SEP 30 2011

...OPHELIA MOVING NORTH-NORTHWESTWARD WITH 105 MPH WINDS...


SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...22.9N 62.7W
ABOUT 665 MI...1070 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...NNW OR 345 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.65 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* BERMUDA

FOR STORM INFORMATION SPECIFIC TO BERMUDA...PLEASE MONITOR PRODUCTS
ISSUED BY THE BERMUDA WEATHER SERVICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 AM AST...1200 UTC...THE CENTER OF HURRICANE OPHELIA WAS
LOCATED NEAR LATITUDE 22.9 NORTH...LONGITUDE 62.7 WEST. OPHELIA IS
MOVING TOWARD THE NORTH-NORTHWEST NEAR 9 MPH...15 KM/H. A TURN TO
THE NORTH WITH AN INCREASE IN FORWARD SPEED IS EXPECTED LATER TODAY.
ON THE FORECAST TRACK...THE CORE OF OPHELIA IS EXPECTED TO PASS
EAST OF BERMUDA ON SATURDAY.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 105 MPH...165 KM/H...
WITH HIGHER GUSTS. OPHELIA IS A CATEGORY TWO HURRICANE ON THE
SAFFIR-SIMPSON HURRICANE WIND SCALE. SOME ADDITIONAL STRENGTHENING
IS POSSIBLE DURING THE NEXT 48 HOURS.

HURRICANE-FORCE WINDS EXTEND OUTWARD UP TO 30 MILES...45 KM...FROM
THE CENTER...AND TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 175
MILES...280 KM...MAINLY TO THE NORTH AND EAST OF THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB...28.65 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL-STORM-FORCE WINDS ARE POSSIBLE ON BERMUDA STARTING
SATURDAY AFTERNOON.

SURF...LARGE SWELLS CREATED BY OPHELIA WILL CAUSE HAZARDOUS SURF
CONDITIONS ALONG THE SOUTH SHORE BEACHES OF BERMUDA.

RAINFALL...RAINFALL ACCUMULATIONS OF 1 TO 2 INCHES CAN BE EXPECTED
ON BERMUDA IN ASSOCIATION WITH OPHELIA.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 AM AST.

$$
FORECASTER AVILA

[TheBurn]

11:30Z Composite VIS/IR & 11:15Z Funktop

[brunota2003]

Oy Ophelia...you just had to strengthen more and ruin my forecast, didn't you? It is 8 am now, and she is a 90 knot hurricane that (barely) met the criteria for RI (35 knots from 2 am to 2 am EDT per Best Track, 50 knots to 85 knots). I'm not going to do the "well, my forecast was made at 8 am, when she was 60 knots, so a 25 knot increase would be 85 knots" thing...my forecast was plain off!

As far as the second forecast, the might hit 80 knots by 8 am was low (90 knots), and I'll bump my intensity forecast up to 100 knots.

[cycloneye]

12z Best Track

Up to 95kts.

AL, 16, 2011093012, , BEST, 0, 229N, 627W, 95, 968, HU

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest

[bexar]

looks more like a major hurricane now to me.

she is quite a small system though.

[CrazyC83]

Could Ophelia become the strongest storm of the season now? We sure have to eat a lot of crow today!

[CrazyC83]

30/1145 UTC 22.9N 62.7W T5.0/5.0 OPHELIA -- Atlantic

[CrazyC83]

It only gets better. Ophelia has done this intensifying under 20-30 kt of shear, the same conditions that have hindered other storms. Mid-level shear has been less than ideal as well the last 24 hours but that disappears too. What in the world? Did she take steroids or something?

http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=sht&zoom=&time=

[bexar]

Could Ophelia become the strongest storm of the season now? We sure have to eat a lot of crow today!

I don't think the waters ahead could support a Cat 4?

[CrazyC83]

Could Ophelia become the strongest storm of the season now? We sure have to eat a lot of crow today!

I don't think the waters ahead could support a Cat 4?

Well, they stay near 28C until just south of Bermuda.

[dwsqos2]

IMO, Ophelia has intensified in an environment of strong upper-level divergence. That can overwhelm shear; think Ida '09 or for that matter any baroclinically enhanced tropical cyclone.

http://i55.tinypic.com/15wyuk5.gif

[wxman57]

looks more like a major hurricane now to me.

she is quite a small system though.

Actually, Ophelia is a little larger than average. TS winds extend out to 175 miles to the NE/SE and 100 miles in the western half. Here, I moved Ophelia into the west-central Gulf for a better perspective of its size:

[CrazyC83]

looks more like a major hurricane now to me.

she is quite a small system though.

Actually, Ophelia is a little larger than average. TS winds extend out to 175 miles to the NE/SE and 100 miles in the western half. Here, I moved Ophelia into the west-central Gulf for a better perspective of its size:

http://myweb.cableone.net/nolasue/op.gif

And this is not going fishing either. Bermuda and Newfoundland are in the crosshairs. The stronger it gets, the worse for them.

[CrazyC83]

I wonder what the 11 am forecast will be. I see no reason why Ophelia cannot become a Cat 4 now if she stays like this or strengthens more approaching the no-shear zone.

[bexar]

Just two days ago, Ophelia was nothing but a Post-tropical low... and look how she came back with a vengeance.

This certainly is a very odd season.

It's also worth nothing that Katia reached MH status in the very same vicinity.

[wxman57]

HURRICANE OPHELIA ADVISORY NUMBER 32
NWS NATIONAL HURRICANE CENTER MIAMI FL AL162011
1100 AM AST FRI SEP 30 2011

...OPHELIA WITH 115 MPH WINDS...BECOMES THE THIRD MAJOR HURRICANE OF
THE 2011 SEASON...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.5N 62.8W
ABOUT 620 MI...1000 KM SSE OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NNW OR 345 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...960 MB...28.35 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* BERMUDA

[dwsqos2]

So, the Atlantic has now produced an above average number of major hurricanes.