Extratropical Irene Advisories

[hurricanefloyd5]

000
WTNT34 KNHC 101439
TCPAT4
BULLETIN
TROPICAL DEPRESSION IRENE ADVISORY NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM AST WED AUG 10 2005

...IRENE GETTING A LITTLE BETTER ORGANIZED OVER THE OPEN ATLANTIC...

AT 11 AM AST...1500Z...THE CENTER OF TROPICAL DEPRESSION IRENE WAS
LOCATED NEAR LATITUDE 22.4 NORTH... LONGITUDE 57.7 WEST OR ABOUT
810 MILES...1305 KM... SOUTHEAST OF BERMUDA AND ABOUT 455 MILES...
730 KM...NORTHEAST OF THE NORTHERN LEEWARD ISLANDS.

THE DEPRESSION IS MOVING TOWARD THE WEST NEAR 10 MPH...17 KM/HR...
AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24
HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH... 55 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS...AND
IRENE COULD REGAIN TROPICAL STORM STATUS LATER TODAY OR THURSDAY.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB...29.80 INCHES.

REPEATING THE 11 AM AST POSITION...22.4 N... 57.7 W. MOVEMENT
TOWARD...WEST NEAR 10 MPH. MAXIMUM SUSTAINED
WINDS... 35 MPH. MINIMUM CENTRAL PRESSURE...1009 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER
AT 5 PM AST.

FORECASTER STEWART

[hurricanefloyd5]

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION IRENE DISCUSSION NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT WED AUG 10 2005

THE CONVECTIVE CLOUD PATTERN THIS MORNING HAS IMPROVED SIGNIFICANTLY
COMPARED TO 24 HOURS AGO. IT IS STILL DIFFICULT...HOWEVER...TO
DETERMINE AN EXACT CENTER LCOATION...ESPECIALLY IN CONVENTIONAL
IMAGERY. THE INITIAL POSITION IS BASED ON CONTINUITY...A 24-HOUR
WESTWARD MOTION...AND TRMM AND MICROWAVE SATELLITE DATA. A 0912Z
QUIKSCAT PASS INTIMATED THAT A LOW-LEVEL CENTER COULD BE FARTHER
SOUTH NEAR 21N...BUT I PREFER TO REMAIN FARTHER NORTH NEAR THE
BETTER DEFINED MID-LEVEL CIRCULATION...WHICH ALSO ALLOWS FOR SOME
POSSIBLE REDEVELOPMENT FARTHER NORTH.

THE INITIAL MOTION ESTIMATE IS 275/10...EVEN THOUGH THE LONGER TERM
MOTION HAS BEEN 270/08. GLOBAL MODEL GUIDANCE HAS CONSISTENTLY
DISPLAYED A 20-30 DEGREE RIGHT-OF-TRACK BIAS THE PAST 48 HOURS.
THIS IS NOT SURPRISING SINCE THE MODELS HAVE KEPT IRENE WEAK OR
HAVE EVEN DISSIPATED IT...ALL THE WHILE MID-LEVEL NORTHERLY FLOW
HAS BEEN KEEPING THE CYCLONE FARTHER SOUTH ON A MORE WESTWARD
TRACK. WATER VAPOR IMAGERY AND SATELLITE-DERIVED WINDS FROM
UW-CIMSS STILL INDICATE A LARGE MID- TO UPPER-LEVEL ANTICYCLONE
LOCATED FROM THE SOUTHEASTERN U.S. EASTWARD ACROSS BERMUDA WITH
DEEP NORTH TO NORTHEASTERLY MID-LEVEL FLOW ON THE EAST SIDE
UNDERCUTTING THE IMPROVING UPPER-LEVEL OUTFLOW PATTERN. SO IN THE
SHORT TERM...A MORE WESTWARD COMPONENT OF MOTION IS PROBABLE...
BARRING ANY NORTHWARD REDEVELOPMENT OF THE LOW-LEVEL CENTER. BY
DAYS 4-5...MOST OF THE GLOBAL MODELS CREATE A WEAKNESS IN THE
SUBTROPICAL RIDGE OFF THE SOUTHEASTERN U.S. COAST...WITH A HIGH
CENTER SHIFTING EASTWARD TO NEAR BERMUDA. THIS IS EXPECTED TO ALLOW
IRENE TO MOVE SLOWLY NORTHWESTWARD AROUND THE SOUTHWEST PERIPHERY
OF THE HIGH. THE OFFICIAL FORECAST IS TO THE LEFT OF THE PREVIOUS
ADVISORY AND IS ON THE EXTREME LEFT...OR SOUTH ...SIDE OF THE NHC
MODEL GUIDANCE ENVELOPE. IF A WESTWARD MOTION CONTINUES TODAY AND
THE CENTER DOES NOT REFORM FARTHER NORTH...THEN THE TRACK WILL HAVE
TO BE SHIFTED EVEN MORE TO THE LEFT ON THE NEXT ADVISORY.

UPPER-LEVEL OUTFLOW HAS BECOME BETTER ESTABLISHED OVER THE PAST 12
HOURS AND IT IS EXPECTED TO CONTINUE TO IMPROVE FOR THE NEXT 3 DAYS
OR SO. HOWEVER...THE AFOREMENTIONED MID-LEVEL NORTHERLY FLOW
UNDERCUTTING THE OUTFLOW LAYER IS PRODUCING SOME MID-LEVEL SHEAR...
AS WELL AS ADVECTING VERY DRY AIR INTO THE SYSTEM. THE WARM
SEA-SURFACE TEMPERATURES AND IMPROVING OUTFLOW PATTERN SHOULD ALLOW
FOR AT LEAST SLOW INTENSIFICATION AS INTERMITTENT BURSTS OF DEEP
CONVECTION OCCUR NEAR THE CENTER. IT IS POSSIBLE THAT IRENE COULD
REACH HURRICANE STRENGTH BEFORE THE END OF THE FORECAST PERIOD.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 10/1500Z 22.4N 57.7W 30 KT
12HR VT 11/0000Z 22.8N 59.4W 35 KT
24HR VT 11/1200Z 23.7N 61.9W 40 KT
36HR VT 12/0000Z 24.6N 64.3W 45 KT
48HR VT 12/1200Z 25.7N 66.6W 50 KT
72HR VT 13/1200Z 27.2N 69.3W 55 KT
96HR VT 14/1200Z 28.5N 71.5W 60 KT
120HR VT 15/1200Z 31.5N 74.5W 60 KT

[wxwatcher91]

just looking over the NHC products...

in the wind chart we now have a figure other than <2% in the cat 4-5 section at 72 hrs... I know 2% isnt a huge news flash but it also indicates that the percentage is higher at 96hrs and 120hrs...

[artist]

ok - here is their 5 AM track - is it NOT the same as the 11 AM whcih they just stated was being moved ?

THE OFFICIAL FORECAST IS TO THE LEFT OF THE PREVIOUS
ADVISORY AND IS ON THE EXTREME LEFT...OR SOUTH ...SIDE OF THE NHC
MODEL GUIDANCE ENVELOPE.

<img src="http://216.77.188.54/coDataImages/p/Groups/242/242637/folders/206854/1641569irene.jpg" width="470" height="376">

[Brent]

It is a little farther southwest:

5am:

INITIAL 10/0900Z 22.4N 57.3W 25 KT
12HR VT 10/1800Z 22.9N 59.0W 25 KT
24HR VT 11/0600Z 23.7N 61.1W 30 KT
36HR VT 11/1800Z 24.6N 63.4W 35 KT
48HR VT 12/0600Z 25.7N 65.5W 40 KT
72HR VT 13/0600Z 27.0N 68.0W 40 KT
96HR VT 14/0600Z 28.5N 70.5W 45 KT
120HR VT 15/0600Z 30.0N 73.0W 50 KT

11am:

INITIAL 10/1500Z 22.4N 57.7W 30 KT
12HR VT 11/0000Z 22.8N 59.4W 35 KT
24HR VT 11/1200Z 23.7N 61.9W 40 KT
36HR VT 12/0000Z 24.6N 64.3W 45 KT
48HR VT 12/1200Z 25.7N 66.6W 50 KT
72HR VT 13/1200Z 27.2N 69.3W 55 KT
96HR VT 14/1200Z 28.5N 71.5W 60 KT
120HR VT 15/1200Z 31.5N 74.5W 60 KT

[artist]

Thanks Brent - seems to me it is not on the south side of their original though, is it?

[vbhoutex]

Wxwatcher 91, with an apparently intensifying tropical system I would expect those numbers to rise some. Past that I would nor read anything into the changes.

[Brent]

Thanks Brent - seems to me it is not on the south side of their original though, is it?

I think they mean the south side of the model consensus, which is correct:

[yoda]

With that map.. I can't see the track moving much.. maybe a tad left...

[cycloneye]

TROPICAL DEPRESSION IRENE DISCUSSION NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT WED AUG 10 2005

IRENE'S CONVECTIVE CLOUD STRUCTURE AND OUTFLOW PATTERN CONTINUE TO
IMPROVE. HOWEVER...IT STILL REMAINS DIFFICULT TO PINPOINT AN EXACT
LOCATION OF THE LOW-LEVEL CENTER....BUT IT IS BELIEVED TO BE
SOUTHWEST OF THE MID-LEVEL CIRCULATION WHERE A FEW NEW CELLS HAVE
BEEN ROTATING CYCLONICALLY THE LAST COUPLE OF HOURS. SATELLITE
INTENSITY ESTIMATES ARE 30 KT FROM TAFB AND SAB...AND 35 KT FROM
AFWA AND THE MOST RECENT ODT VALUES...SUGGESTING THAT IRENE IS VERY
NEAR REGAINING TROPICAL STORM STATUS. HOWEVER...UNTIL SOME CENTRAL
CONVECTION PERSISTS...THE INTENSITY WILL BE HELD AT 30 KT.

THE INITIAL MOTION ESTIMATE IS 285/11. THE NHC MODEL GUIDANCE...
ESPECIALLY THE GLOBAL MODELS...HAVE MADE A SIGNIFICANT WESTWARD
SHIFT SINCE 06Z. IN FACT...THE GFS 10-MEMBER ENSEMBLE MODEL HAS
MADE A 450 NMI WESTWARD SHIFT AT 120 HOURS. THE LONE OUTLIER MODEL
IS THE UKMET ...WHICH INSISTS THAT IRENE WILL PLOW NORTHWESTWARD
THROUGH THE STRONG SUBTROPICAL RIDGE TO THE NORTH. THIS SOLUTION
WAS DISCOUNTED GIVEN THE 5950 METER 500 MB HEIGHTS AT BERMUDA AND A
WEST WIND OF 10 KT...WHICH SUGGESTS THE HIGH CENTER IS SOUTHWEST OF
BERMUDA AND DIRECTLY IN THE PATH OF THE UKMET SOLUTION. EXCLUDING
THE UKMET MODEL...THE REST OF THE NHC MODEL GUIDANCE IS TIGHTLY
CLUSTERED ABOUT THE PREVIOUS FORECAST TRACK THROUGH 72 HOURS WITH
LESS THAN A 60 NMI SPREAD. AFTER THAT...HOWEVER...THE MODELS
DIVERGE SIGNIFICANTLY BASED ON HOW THEY HANDLE THE DEVELOPMENT OF A
WEAKNESS IN THE SUBTROPICAL RIDGE OFF THE SOUTHEASTERN U.S. BY DAY
4. THE DYNAMICAL MODELS...ESPECIALLY THE CANADIAN...ARE MUCH LESS
ROBUST WITH DEVELOPING A SIGNIFICANT WEAKNESS IN THE RIDGE. THIS
SEEMS QUITE REASONABLE GIVEN THE CURRENT STRENGTH AND EAST-WEST
EXTENT OF THE RIDGE AXIS...AND THE FACT THAT EACH MODEL MAINTAINS
HIGHLY ZONAL FLOW ACROSS THE NORTHERN U.S. AND THE NORTHWESTERN
ATLANTIC. SUCH FAST MOVING WESTERLY MID- TO UPPER-LEVEL FLOW TENDS
NOT TO BE CONDUCIVE FOR SHORTWAVES TO DIG SOUTHWARD AND WEAKEN THE
RIDGE LIKE SOME OF THE MODELS ARE SUGGESTING. THE GFDN MODEL IS THE
FASTEST AND WESTERNMOST MODEL AND TAKES IRENE TO NEAR THE SOUTH
CAROLINA COAST BY 120H...WHILE THE NOGAPS MODEL BRINGS IRENE TO
ABOUT 90 NMI EAST OF THE OUTER BANKS OF NORTH CAROLINA. THE
OFFICIAL FORECAST TRACK REMAINS NEAR THE LEFT SIDE OF THE GUIDANCE
ENVELOPE AND IS JUST AND EXTENSION OF THE PREVIOUS FORECAST TRACK.

THE UPPER-LEVEL OUTFLOW PATTERN IS EXPECTED TO CONTINUE TO IMPROVE
THROUGHOUT THE FORECAST PERIOD WITH VERTICAL SHEAR REMAINING AROUND
10 KT OR LESS. HOWEVER...NORTHEASTERLY MID-LEVEL SHEAR IS EXPECTED
TO PERSIST FOR THE NEXT 36 HOURS...AND MID-LEVEL HUMIDITY IS
FORECAST TO DECREASE TO AS LOW AS 26 PERCENT BY DAYS 4 AND 5. SSTS
ARE EXPECTED TO REMAIN NEAR 29C ALONG THE TRACK...SO THE DRY
MID-LEVEL AIR WILL BE THE MAIN INHIBITING FACTOR. HOWEVER...
HURRICANES CAN STILL FORM IN SUCH DRY CONDITIONS...AND THAT IS
INDICATED BY THE SHIPS MODEL AND THE OFFICIAL FORECAST. ONE THING
THAT THE VERY DRY MID-LEVEL AIR SHOULD ENSURE IS THAT OUTER
CONVECTIVE BANDS WILL NOT EXTEND FAR FROM THE CENTER...WHICH SHOULD
HELP TO KEEP IRENE A RELATIVELY SMALL TROPICAL CYCLONE...AND SMALL
TROPICAL CYCLONES TEND NOT TO PLOW THROUGH STRONG RIDGES.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 10/2100Z 22.8N 58.8W 30 KT
12HR VT 11/0600Z 23.2N 60.4W 35 KT
24HR VT 11/1800Z 24.1N 62.8W 40 KT
36HR VT 12/0600Z 25.1N 65.1W 45 KT
48HR VT 12/1800Z 26.1N 67.3W 50 KT
72HR VT 13/1800Z 27.4N 69.6W 55 KT
96HR VT 14/1800Z 29.5N 72.5W 65 KT
120HR VT 15/1800Z 32.0N 75.5W 70 KT

[Brent]

TROPICAL DEPRESSION IRENE FORECAST/ADVISORY NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092005
2100Z WED AUG 10 2005

TROPICAL DEPRESSION CENTER LOCATED NEAR 22.8N 58.8W AT 10/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 11 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1007 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
12 FT SEAS..150NE 150SE 50SW 90NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 22.8N 58.8W AT 10/2100Z
AT 10/1800Z CENTER WAS LOCATED NEAR 22.6N 58.2W

FORECAST VALID 11/0600Z 23.2N 60.4W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 50NE 30SE 30SW 50NW.

FORECAST VALID 11/1800Z 24.1N 62.8W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 50NE 30SE 30SW 50NW.

FORECAST VALID 12/0600Z 25.1N 65.1W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 50NE 30SE 30SW 50NW.

FORECAST VALID 12/1800Z 26.1N 67.3W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 60NE 45SE 45SW 60NW.

FORECAST VALID 13/1800Z 27.4N 69.6W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 25NE 20SE 10SW 25NW.
34 KT... 60NE 55SE 45SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 325 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 14/1800Z 29.5N 72.5W
MAX WIND 65 KT...GUSTS 80 KT.

OUTLOOK VALID 15/1800Z 32.0N 75.5W
MAX WIND 70 KT...GUSTS 85 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 22.8N 58.8W

NEXT ADVISORY AT 11/0300Z

FORECASTER STEWART

[Brent]

[yoda]

Leaning towards the GFS/GFDL? Never seen that before...

[Brent]

BULLETIN
TROPICAL DEPRESSION IRENE ADVISORY NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM AST WED AUG 10 2005

...IRENE CONTINUES TO BECOME BETTER ORGANIZED...

AT 5 PM AST...2100Z...THE CENTER OF TROPICAL DEPRESSION IRENE WAS
LOCATED NEAR LATITUDE 22.8 NORTH... LONGITUDE 58.8 WEST OR ABOUT
750 MILES...1210 KM... SOUTH-SOUTHEAST OF BERMUDA.

THE DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST NEAR 13 MPH
...20 KM/HR. A MOTION BETWEEN WEST AND WEST-NORTHWEST IS EXPECTED TO
CONTINUE FOR THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH... 55 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS...AND
IRENE COULD REGAIN TROPICAL STORM STATUS LATER TONIGHT OR ON
THURSDAY.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB...29.74 INCHES.

REPEATING THE 5 PM AST POSITION...22.8 N... 58.8 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 13 MPH. MAXIMUM SUSTAINED
WINDS... 35 MPH. MINIMUM CENTRAL PRESSURE...1007 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER
AT 11 PM AST.

FORECASTER STEWART

[gkrangers]

Two thoughts on Stewarts wording...

1) He reamed the UKMET...see where he speaks of it, and the last line of the discussion.

2) He's definitely onboard for a landfall..IMO.

[Thunder44]

Whew! That was some discussion.

[MWatkins]

...WHICH SHOULD HELP TO KEEP IRENE A RELATIVELY SMALL TROPICAL CYCLONE...AND SMALL TROPICAL CYCLONES TEND NOT TO PLOW THROUGH STRONG RIDGES.

Awesome quote...absolutely awesome.

MW

[deltadog03]

very good disco again...stewart is always really good...only one bad thing i see...i don't see a 285 movement....but, hey the center is hard to find

[yoda]

...WHICH SHOULD HELP TO KEEP IRENE A RELATIVELY SMALL TROPICAL CYCLONE...AND SMALL TROPICAL CYCLONES TEND NOT TO PLOW THROUGH STRONG RIDGES.

Awesome quote...absolutely awesome.

MW

Which means it would follow the periphery of the ridge?

[gkrangers]

...WHICH SHOULD HELP TO KEEP IRENE A RELATIVELY SMALL TROPICAL CYCLONE...AND SMALL TROPICAL CYCLONES TEND NOT TO PLOW THROUGH STRONG RIDGES.

Awesome quote...absolutely awesome.

MW

Which means it would follow the periphery of the ridge?

Yes. But it was mostly there to poke fun at the UKMET...I think so anyway.