EPAC: Tropical Depression Ivo=Last Advisory

[CrazyC83]

T4.5/4.5 from TAFB too so I will not be surprised to see 75 kt.

I agree, I think 70 or 75 knots at this point.

[Chacor]

They held at 65, which imo is rather conservative.

[Derek Ortt]

may be aggressive holding the intensity at 65KT with the objective estimates (which usually over-estimate anything without a well-defined eye) and the pitiful sat appearance this morning. It looks like a 3.5/4.0 not a 4.5/4.5 to me

[HurricaneRobert]

I see the eye again.

[CrazyC83]

20/1800 UTC 17.6N 112.9W T4.5/4.5 IVO

No change.

[HURAKAN]

942
WHXX01 KMIA 201834
CHGE77
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1834 UTC THU SEP 20 2007

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

EAST PACIFIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE IVO (EP122007) 20070920 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
070920 1800 070921 0600 070921 1800 070922 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 17.5N 113.0W 18.7N 113.9W 20.3N 114.8W 22.0N 115.0W
BAMD 17.5N 113.0W 18.6N 113.6W 20.0N 113.8W 21.7N 113.8W
BAMM 17.5N 113.0W 18.9N 113.3W 20.4N 113.5W 22.1N 113.6W
LBAR 17.5N 113.0W 18.8N 113.2W 20.5N 113.3W 22.5N 113.2W
SHIP 70KTS 72KTS 72KTS 69KTS
DSHP 70KTS 72KTS 72KTS 69KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
070922 1800 070923 1800 070924 1800 070925 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 23.6N 115.2W 26.2N 114.9W 28.6N 114.9W 31.1N 116.1W
BAMD 23.6N 113.7W 28.1N 111.3W 32.3N 104.5W 33.0N 96.7W
BAMM 23.8N 113.6W 27.3N 112.3W 30.6N 109.3W 32.5N 107.2W
LBAR 24.9N 112.7W 31.5N 109.4W 39.3N 102.1W .0N .0W
SHIP 64KTS 56KTS 45KTS 42KTS
DSHP 64KTS 56KTS 40KTS 39KTS

...INITIAL CONDITIONS...
LATCUR = 17.5N LONCUR = 113.0W DIRCUR = 335DEG SPDCUR = 6KT
LATM12 = 16.2N LONM12 = 112.4W DIRM12 = 326DEG SPDM12 = 6KT
LATM24 = 15.2N LONM24 = 111.6W
WNDCUR = 70KT RMAXWD = 15NM WNDM12 = 65KT
CENPRS = 981MB OUTPRS = 1010MB OUTRAD = 190NM SDEPTH = M
RD34NE = 75NM RD34SE = 65NM RD34SW = 30NM RD34NW = 60NM

[cycloneye]

034
WTPZ42 KNHC 202028
TCDEP2
HURRICANE IVO DISCUSSION NUMBER 10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP122007
200 PM PDT THU SEP 20 2007

EARLIER MICROWAVE IMAGERY SHOWS A WELL-DEFINED EYE FEATURE EVEN
THOUGH IT IS ONLY INTERMITTENTLY VISIBLE IN CONVENTIONAL IMAGERY.
THE CONSENSUS OF THE VARIOUS SATELLITE INTENSITY ESTIMATES IS
AROUND 70 KT AND THIS WILL BE THE INITIAL INTENSITY ESTIMATE.

IVO IS ESSENTIALLY MOVING ALONG THE PREVIOUS FORECAST TRACK WITH AN
INITIAL MOTION ESTIMATE OF 345/7. IN THE SHORT-TERM...IVO IS
EXPECTED TO TURN NORTHWARD AROUND THE WESTERN PERIPHERY OF A
MID-LEVEL RIDGE EXTENDING WESTWARD FROM THE SOUTHERN BAJA
PENINSULA. THIS RIDGE WILL WEAKEN OVER THE NEXT COUPLE OF DAYS AS
A LARGE DEEP-LAYER CUTOFF LOW FORMS OFF THE CALIFORNIA COAST. THIS
EVOLUTION IS EXPECTED TO CAUSE VERY WEAK STEERING CURRENTS
RESULTING IN A HIGHLY UNCERTAIN FORECAST BEYOND 48 HOURS. NOT
SURPRISINGLY...DYNAMICAL MODELS OFFER A LARGE SPECTRUM OF SOLUTIONS
RANGING FROM THE ECMWF...WHICH SHOWS A RAPIDLY WEAKENING CYCLONE
ABRUPTLY STOPPING AND TURNING BACK TO THE SOUTH...TO THE NOGAPS AND
GFDN MODELS WHICH MAINTAIN A DEEP SYSTEM AND ACCELERATING IT
NORTHWARD WITHIN THE SOUTHERLY FLOW EAST OF THE AFOREMENTIONED
CUTOFF LOW. THE GFDL IS SOMEWHERE IN BETWEEN AS IT SHOWS THE
CYCLONE REMAINING DEEP BUT MEANDERING WITHIN THE WEAK STEERING
ENVIRONMENT. AT THIS TIME IT IS DIFFICULT TO DISTINGUISH WHICH OF
THESE SOLUTIONS IS MOST LIKELY AND THE OFFICIAL FORECAST IS CLOSE
TO THE DYNAMICAL MODEL CONSENSUS. THE NEW FORECAST REPRESENTS A
SMALL NORTHWARD SHIFT PRIMARILY AT DAYS 4 AND 5.

THE OVERALL ENVIRONMENT LOOKS MARGINAL FOR STRENGTHENING. ON ONE
HAND THE OCEAN IS SUFFICIENTLY WARM ALONG THE FORECAST TRACK AND
THE SHEAR IS EXPECTED TO REMAIN LOW FOR ABOUT 48 HOURS.
HOWEVER...AN UPPER-LEVEL SHEAR AXIS TO THE NORTHWEST OF CYCLONE IS
RESTRICTING OUTFLOW AND PRODUCING A LARGE AREA OF SUBSIDENCE AND
DRY AIR. IVO COULD ALSO BECOME THERMODYNAMICALLY CHALLENGED GIVEN
THE PRESENCE OF RELATIVELY STABLE AIR TO THE NORTH. THE OFFICIAL
INTENSITY FORECAST IS LOWERED SLIGHTLY WHICH IS ALSO CONSISTENT
WITH THE TREND IN THE MODELS.

GIVEN THE EXTREME UNCERTAINTY PRESENT IN THE OFFICIAL FORECAST AT
THIS TIME...INTERESTS IN SOUTHERN BAJA CALIFORNIA SHOULD CLOSELY
MONITOR THE PROGRESS OF IVO.

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/2100Z 17.8N 113.1W 70 KT
12HR VT 21/0600Z 18.5N 113.3W 70 KT
24HR VT 21/1800Z 19.5N 113.2W 70 KT
36HR VT 22/0600Z 20.4N 112.9W 70 KT
48HR VT 22/1800Z 21.2N 112.5W 65 KT
72HR VT 23/1800Z 22.9N 111.8W 60 KT
96HR VT 24/1800Z 24.5N 111.5W 50 KT...INLAND OVER BAJA
120HR VT 25/1800Z 26.5N 111.5W 30 KT...INLAND OVER BAJA

$$
FORECASTER RHOME

[HURAKAN]

861
WHXX01 KMIA 210128
CHGE77
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0128 UTC FRI SEP 21 2007

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

EAST PACIFIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE IVO (EP122007) 20070921 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
070921 0000 070921 1200 070922 0000 070922 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 18.4N 113.3W 19.9N 114.0W 21.8N 114.2W 23.6N 114.2W
BAMD 18.4N 113.3W 19.7N 113.6W 21.4N 113.6W 23.4N 113.4W
BAMM 18.4N 113.3W 19.9N 113.7W 21.6N 114.0W 23.4N 114.2W
LBAR 18.4N 113.3W 20.1N 113.3W 22.3N 113.0W 25.2N 112.3W
SHIP 70KTS 70KTS 66KTS 64KTS
DSHP 70KTS 70KTS 66KTS 64KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
070923 0000 070924 0000 070925 0000 070926 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 25.3N 114.1W 27.8N 112.9W 29.8N 111.8W 31.4N 112.1W
BAMD 25.6N 113.0W 30.9N 108.6W 34.8N 99.9W 38.4N 89.9W
BAMM 25.3N 114.0W 29.2N 112.0W 32.1N 107.9W 33.5N 103.5W
LBAR 28.6N 111.4W 28.2N 102.6W 27.1N 101.0W 26.0N 100.5W
SHIP 59KTS 52KTS 42KTS 37KTS
DSHP 59KTS 52KTS 35KTS 34KTS

...INITIAL CONDITIONS...
LATCUR = 18.4N LONCUR = 113.3W DIRCUR = 339DEG SPDCUR = 9KT
LATM12 = 16.8N LONM12 = 112.8W DIRM12 = 333DEG SPDM12 = 7KT
LATM24 = 15.8N LONM24 = 112.1W
WNDCUR = 70KT RMAXWD = 15NM WNDM12 = 65KT
CENPRS = 981MB OUTPRS = 1010MB OUTRAD = 190NM SDEPTH = D
RD34NE = 75NM RD34SE = 65NM RD34SW = 30NM RD34NW = 60NM

$$
NNNN

[cycloneye]

808
WTPZ42 KNHC 210236
TCDEP2
HURRICANE IVO DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP122007
800 PM PDT THU SEP 20 2007

SATELLITE IMAGES INDICATE THAT A LARGE BURST OF CONVECTION IS NEAR
THE CENTER OF IVO. EVEN THOUGH AN EYE IS NOT VISIBLE IN
CONVENTIONAL IMAGERY...MICROWAVE DATA SHOW AN EYE WHICH HAS BEEN
OCCASIONALLY OPEN. THERE HAS BEEN LITTLE CHANGE IN THE SATELLITE
INTENSITY ESTIMATES AND THE INITIAL INTENSITY IS LEFT AT 70 KT.
ALTHOUGH THE FORECAST SHEAR IS LIGHT AND THE WATER RELATIVELY
WARM...NONE OF THE RELIABLE INTENSITY MODELS SHOW ANY STRENGTHENING
WITH IVO. PERHAPS THIS IS DUE TO THE HURRICANE MOVING CLOSER TO
THE RELATIVELY STABLE AIR TO THE NORTH. IN ANY EVENT...THE
INTENSITY FORECAST IS ALMOST THE SAME AS THE PREVIOUS ONE IN THE
SHORT-TERM...BUT A LITTLE LOWER BEYOND 2 DAYS BECAUSE MOST MODELS
SHOW INCREASING SHEAR AND THE SYSTEM WILL LIKELY BE INTERACTING
WITH LAND.

SSMI AND AMSR-E MICROWAVE DATA SHOW THAT IVO IS MOVING FASTER
TONIGHT TOWARD THE NORTH...350/8. THE TRACK FORECAST IS
PROBLEMATIC TO SAY THE LEAST. FOR THE NEXT DAY OR SO...THE
HURRICANE WILL BE TRAVELING NORTHWARD IN AN AREA OF WEAK STEERING
CURRENTS BETWEEN A RIDGE OVER CENTRAL MEXICO AND A RATHER DEEP
MIDDLE- TO UPPER-LEVEL LOW OFFSHORE OF SOUTHERN CALIFORNIA. THE
MODELS ARE IN RATHER POOR AGREEMENT ON WHETHER IVO WILL EVENTUALLY
GET CAUGHT UP IN THE SOUTHWESTERLY FLOW AHEAD OF THE LOW OR GET
LEFT BEHIND IN THE AREA OF LIGHT STEERING CURRENTS. THE
NOGAPS/UKMET/HWRF MODELS FAVOR THE SYSTEM GETTING CARRIED TO THE
NORTHEAST RATHER QUICKLY AND IMPACTING BAJA CALIFORNIA...WHILE THE
GFS/ECMWF/GFDN/GFDL MODELS DO NOT SHOW ANY LAND IMPACTS. THE
OFFICIAL TRACK FORECAST IS A LITTLE FASTER IN THE FIRST DAY DUE TO
THE INITIAL MOTION BUT IS CLOSE TO THE CONSENSUS IN THE LONG-TERM.

GIVEN THE EXTREME UNCERTAINTY PRESENT IN THE OFFICIAL FORECAST AT
THIS TIME...INTERESTS IN SOUTHERN BAJA CALIFORNIA SHOULD CLOSELY
MONITOR THE PROGRESS OF IVO.

FORECAST POSITIONS AND MAX WINDS

INITIAL 21/0300Z 18.8N 113.4W 70 KT
12HR VT 21/1200Z 19.7N 113.5W 70 KT
24HR VT 22/0000Z 20.6N 113.1W 70 KT
36HR VT 22/1200Z 21.3N 112.8W 65 KT
48HR VT 23/0000Z 22.0N 112.5W 60 KT
72HR VT 24/0000Z 23.5N 112.0W 55 KT
96HR VT 25/0000Z 25.0N 111.5W 45 KT...INLAND OVER BAJA
120HR VT 26/0000Z 26.5N 111.5W 30 KT...INLAND OVER BAJA

$$
FORECASTER BLAKE

[HURAKAN]

HURRICANE IVO DISCUSSION NUMBER 12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP122007
200 AM PDT FRI SEP 21 2007

THE EYE OF IVO MADE AN APPEARANCE IN INFRARED IMAGERY AROUND 0600
UTC...AND THEN VERY QUICKLY DISAPPEARED. SINCE THEN...THE OVERALL
SATELLITE APPEARANCE HAS BECOME RAGGED...WITH EVIDENCE OF WESTERLY
VERTICAL WIND SHEAR UNDERCUTTING THE OUTFLOW ON THE WEST SIDE.
SATELLITE INTENSITY ESTIMATES REMAIN 77 KT FROM TAFB AND SAB...AND
THE INITIAL INTENSITY REMAINS 70 KT.

IVO HAS SLOWED ITS FORWARD SPEED OVER THE PAST FEW HOURS WITH THE
MOTION ESTIMATED AT 340/7. WATER VAPOR IMAGERY INDICATES A LARGE
UPPER-LEVEL LOW JUST WEST OF THE COAST OF SOUTHERN CALIFORNIA...
WITH WHAT IS BECOMING A NORTH-SOUTH ORIENTED RIDGE EAST OF IVO.
THE LARGE-SCALE MODELS AGREE THAT THE LOW SHOULD BEGIN MOVING
NORTHEASTWARD IN 24-36 HR. HOWEVER...THAT IS ABOUT ALL THEY AGREE
ON...AS THEY HAVE A WIDE VARIETY OF SOLUTIONS FOR THE TRACK OF IVO.
THE ECMWF CONTINUES TO FORECAST IVO TO REACH 20N...THEN MOVE
SOUTHWARD AND DISSIPATE. THE GFS AND GFDL FORECAST IVO TO MOVE
SLOWLY NORTHWARD AND STALL BEFORE REACHING BAJA CALIFORNIA. THE
UKMET...HWRF...AND NOGAPS...MOVE IVO NORTHWARD ACROSS BAJA...WITH
THE UKMET CALLING FOR LANDFALL IN LESS THAN 48 HR. GIVEN THE
UNCERTAINTY...THE NEW FORECAST TRACK IS ESSENTIALLY AN UPDATE OF
THE PREVIOUS TRACK...CALLING FOR THE CENTER OF IVO TO REACH BAJA IN
72-96 HR. HOPEFULLY SUBSEQUENT MODEL RUNS WILL COME INTO BETTER
AGREEMENT ON THE FORECAST FORWARD SPEED.

WATER VAPOR IMAGERY SUGGESTS THERE IS MORE WESTERLY SHEAR AFFECTING
IVO THAN CURRENTLY ANALYZED BY THE LARGE-SCALE MODELS OR SHIPS
MODEL. THE IMAGERY ALSO SHOWS DRY AIR WEST OF THE HURRICANE THAT
THE SHEAR MAY ADVECT INTO THE SYSTEM AS IT MOVES NORTHWARD OVER
COOLER WATERS. THE GFS AND UKMET FORECAST FAVORABLE UPPER-LEVEL
WINDS ALONG THE FORECAST TRACK...WITH THE ECMWF AND NOGAPS SHOWING
A MORE HOSTILE ENVIRONMENT. THE SHIPS MODEL FORECASTS A SLOW
WEAKENING AFTER 24 HR...WHILE THE HWRF AND THE GFDL SHOW A STRONGER
SYSTEM WITH NO APPRECIABLE WEAKENING UNTIL AFTER 60 HR. GIVEN THE
CURRENT SHEAR...THE INTENSITY FORECAST WILL GO WITH THE SLOW DECAY
FROM THE SHIPS MODEL AND IS SIMILAR TO THE PREVIOUS FORECAST.

GIVEN THE EXTREME UNCERTAINTY PRESENT IN THE OFFICIAL FORECAST AT
THIS TIME...INTERESTS IN SOUTHERN BAJA CALIFORNIA SHOULD CLOSELY
MONITOR THE PROGRESS OF IVO.


FORECAST POSITIONS AND MAX WINDS

INITIAL 21/0900Z 19.0N 113.5W 70 KT
12HR VT 21/1800Z 19.9N 113.5W 70 KT
24HR VT 22/0600Z 20.8N 113.2W 70 KT
36HR VT 22/1800Z 21.5N 112.9W 65 KT
48HR VT 23/0600Z 22.3N 112.5W 60 KT
72HR VT 24/0600Z 24.0N 112.0W 55 KT
96HR VT 25/0600Z 25.5N 111.5W 40 KT...INLAND
120HR VT 26/0600Z 27.0N 111.5W 30 KT...OVER WATER

$$
FORECASTER BEVEN

[HURAKAN]

048
WHXX01 KMIA 211240
CHGE77
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1240 UTC FRI SEP 21 2007

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

EAST PACIFIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE IVO (EP122007) 20070921 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
070921 1200 070922 0000 070922 1200 070923 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 19.3N 113.6W 21.0N 114.1W 22.6N 114.5W 24.0N 114.7W
BAMD 19.3N 113.6W 20.9N 113.6W 22.7N 113.7W 24.8N 113.3W
BAMM 19.3N 113.6W 20.8N 113.9W 22.4N 114.2W 23.9N 114.2W
LBAR 19.3N 113.6W 20.8N 113.4W 22.7N 112.8W 24.9N 112.4W
SHIP 65KTS 59KTS 55KTS 51KTS
DSHP 65KTS 59KTS 55KTS 51KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
070923 1200 070924 1200 070925 1200 070926 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 24.8N 114.6W 26.2N 114.5W 27.4N 115.1W 29.1N 116.0W
BAMD 27.0N 112.1W 31.0N 105.9W 32.7N 98.0W 33.8N 90.4W
BAMM 25.3N 113.8W 28.2N 112.3W 30.7N 111.2W 34.1N 109.0W
LBAR 28.6N 110.5W 37.7N 104.8W .0N .0W .0N .0W
SHIP 48KTS 40KTS 33KTS 30KTS
DSHP 48KTS 40KTS 30KTS 30KTS

...INITIAL CONDITIONS...
LATCUR = 19.3N LONCUR = 113.6W DIRCUR = 340DEG SPDCUR = 5KT
LATM12 = 18.4N LONM12 = 113.3W DIRM12 = 342DEG SPDM12 = 6KT
LATM24 = 16.8N LONM24 = 112.8W
WNDCUR = 65KT RMAXWD = 15NM WNDM12 = 70KT
CENPRS = 987MB OUTPRS = 1010MB OUTRAD = 190NM SDEPTH = D
RD34NE = 75NM RD34SE = 65NM RD34SW = 30NM RD34NW = 60NM

[CrazyC83]

Looks like it is weakening now.

[cycloneye]

966
WTPZ42 KNHC 211455
TCDEP2
HURRICANE IVO DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP122007
800 AM PDT FRI SEP 21 2007

WHILE BOTH TRMM AND AMSR-E MICROWAVE PASSES FROM AROUND 0900 UTC
DEPICTED AN EYE FEATURE...CONVENTIONAL SATELLITE IMAGERY SHOWS THAT
THE OVERALL CLOUD PATTERN OF IVO HAS DETERIORATED. CLOUD TOPS HAVE
WARMED AND WESTERLY SHEAR IS STILL IMPINGING UPON THE WESTERN SIDE
OF THE CYCLONE. EVEN THOUGH DVORAK CURRENT INTENSITY ESTIMATES FROM
TAFB AND SAB REMAIN AT 77 KT...PRIMARILY DUE TO CONSTRAINTS...3-
AND 6-HOURLY ADT INTENSITY ESTIMATES FROM CIMSS ARE ONLY 45-55 KT.
BASED ON THE ABOVE...THE INITIAL INTENSITY IS LOWERED TO 65
KT...WHICH STILL COULD BE GENEROUS. FIRST LIGHT VISIBLE IMAGERY
INDICATES THAT THE CENTER OF IVO COULD BE SLIGHTLY TO THE EAST OF
THE CURRENT ADVISORY LOCATION.

IVO CONTINUES TO DECELERATE AND THE ESTIMATED MOTION IS NOW 350/6.
A LARGE MID- TO UPPER-LEVEL LOW DIGGING SOUTHWARD IS CURRENTLY
CENTERED OFF THE COAST OF SOUTHERN CALIFORNIA...AND A NORTH-SOUTH
ORIENTED RIDGE IS SITUATED TO THE EAST OF IVO. THE FORECAST TRACK
OF IVO IS HIGHLY DEPENDENT UPON THE STRENGTH OF THESE TWO FEATURES.
THE DYNAMICAL MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT THAT THE
LOW SHOULD MOVE NORTHEASTWARD IN 36 HOURS OR SO...BUT DISAGREE IN
HOW MUCH TROUGHING WILL LINGER BEHIND TO MAINTAIN A NORTHWARD TO
NORTHEAST MOTION OF IVO. THE HWRF...NOGAPS...AND UKMET MODELS KEEP
ENOUGH TROUGHING TO INDUCE A MORE NORTHWARD TO NORTHEASTWARD MOTION
WITH A TRACK ACROSS SOUTHERN BAJA IN 3 OR SO DAYS. ON THE OTHER
HAND...THE GFS...ECMWF...AND GFDL SOLUTIONS STALL IVO WELL TO THE
SOUTHWEST OF THE BAJA PENINSULA. DUE TO THE UNCERTAINTY...THE
OFFICIAL TRACK FORECAST IS AN UPDATE OF THE PREVIOUS TRACK AND
TAKES THE CENTER OF IVO ACROSS THE BAJA PENINSULA IN 72 HOURS OR
SO...IN LINE WITH THE HWRF...NOGAPS...UKMET SUITE.

BASED ON WATER VAPOR IMAGERY THE WESTERLY SHEAR APPEARS TO BE
STRONGER THAN THE SHIPS AND DYNAMICAL MODELS ARE INDICATING...AND A
WEAKENING TREND APPEARS TO BE UNDERWAY. DESPITE THE WARM WATERS...
THE WESTERLY SHEAR AND POSSIBLY DRY AIR COULD INHIBIT ANY
RESTRENGTHENING. THE OFFICIAL INTENSITY FORECAST IS ADJUSTED
DOWNWARD FROM THE PREVIOUS FORECAST DUE TO THE CURRENT APPEARANCE
OF THE CYCLONE...AND FOLLOWS A BLEND OF THE SHIPS AND GFDL GUIDANCE.

ONCE AGAIN...GIVEN THE EXTREME UNCERTAINTY PRESENT IN THE OFFICIAL
FORECAST AT THIS TIME...INTERESTS IN SOUTHERN BAJA CALIFORNIA SHOULD
CLOSELY MONITOR THE PROGRESS OF IVO.


FORECAST POSITIONS AND MAX WINDS

INITIAL 21/1500Z 19.5N 113.4W 65 KT
12HR VT 22/0000Z 20.4N 113.4W 60 KT
24HR VT 22/1200Z 21.3N 113.1W 60 KT
36HR VT 23/0000Z 22.1N 112.8W 60 KT
48HR VT 23/1200Z 23.0N 112.5W 55 KT
72HR VT 24/1200Z 24.5N 112.0W 50 KT...NEAR BAJA PENINSULA
96HR VT 25/1200Z 26.0N 111.5W 40 KT...INLAND
120HR VT 26/1200Z 27.5N 111.5W 30 KT...OVER WATER

$$
FORECASTER MAINELLI

[Cyclenall]

To me, this doesn't even look like a hurricane at all. I would estimate the strength at 50 knots now.

[CrazyC83]

I'd say 55 knots is the real intensity, down to Tropical Storm Ivo in that case.

[cycloneye]

414
WTPZ42 KNHC 212035
TCDEP2
TROPICAL STORM IVO DISCUSSION NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP122007
200 PM PDT FRI SEP 21 2007

IVO APPEARED TO BE IN A CONVECTIVE LULL ABOUT 5 OR 6 HOURS AGO...
BUT A BURST OF DEEP CONVECTION HAS REDEVELOPED NORTHEAST OF THE
LOW-LEVEL CIRCULATION CENTER DURING THE LAST COUPLE OF HOURS.
DESPITE THE NEW CONVECTION AND A WELL-DEFINED CIRCULATION...DVORAK
DATA T-NUMBERS AND CURRENT INTENSITY ESTIMATES FROM BOTH TAFB AND
SAB ARE 55 KT AND 65 KT RESPECTIVELY. A 1356 UTC QUIKSCAT PASS
ESTIMATED 50 TO 55 KT WIND VECTORS. BLENDING THE ABOVE ESTIMATES
RESULTS IN LOWERING THE INITIAL INTENSITY TO 60 KT. WHILE THE
WATERS ARE EXPECTED TO REMAIN SUFFICIENTLY WARM ALONG THE FORECAST
TRACK...WESTERLY TO SOUTHWESTERLY SHEAR IS FORECAST TO GRADUALLY
INCREASE. THE OFFICIAL INTENSITY FORECAST CALLS FOR SLOW WEAKENING
AFTER 12 HOURS...WHICH FOLLOWS CLOSELY WITH THE INTENSITY MODEL
CONSENSUS OF THE GFDL...SHIPS...AND HWRF.

IVO IS MOVING SLOWLY TO THE NORTH AND THE MOTION IS ESTIMATED AT
005/5. THE GENERAL TRACK PHILOSOPHY IS COMPLICATED AND SOLUTIONS
FROM THE VARIOUS MODELS ARE HIGHLY DIVERGENT. THE MID- TO UPPER-
LEVEL LOW REMAINS CENTERED JUST WEST OF THE SOUTHERN CALIFORNIA
COAST. AS THE LOW LIFTS NORTHEASTWARD IN ABOUT 36 HOURS OR SO...IT
IS DIFFICULT TO DETERMINE HOW MUCH INFLUENCE THE LINGERING TROUGH
BEHIND THE LOW WILL HAVE ON STEERING IVO NORTHEASTWARD. ONLY THE
UKMET AND NOGAPS MODELS ACCELERATE THE CYCLONE NORTHEASTWARD INTO
MAINLAND MEXICO. THE ECMWF...GFS...HWRF...AND GFDL MODELS STALL
IVO SOUTH OF THE BAJA PENINSULA COAST IN ABOUT 3 DAYS. THE
OFFICIAL TRACK FORECAST STILL CALLS FOR IVO TO MOVE ACROSS THE
SOUTHERN BAJA PENINSULA... BUT AT A SLOWER PACE AND SLIGHTLY TO
THE EAST OF THE PREVIOUS FORECAST...WHICH IS CLOSEST TO THE FSSE
GUIDANCE.

ONCE AGAIN...GIVEN THE UNCERTAINTY PRESENT IN THE OFFICIAL
FORECAST...INTERESTS IN SOUTHERN BAJA CALIFORNIA SHOULD CLOSELY
MONITOR THE PROGRESS OF IVO.


FORECAST POSITIONS AND MAX WINDS

INITIAL 21/2100Z 20.1N 113.4W 60 KT
12HR VT 22/0600Z 20.8N 113.2W 60 KT
24HR VT 22/1800Z 21.6N 112.9W 55 KT
36HR VT 23/0600Z 22.3N 112.6W 50 KT
48HR VT 23/1800Z 23.0N 112.2W 45 KT
72HR VT 24/1800Z 24.0N 111.5W 40 KT
96HR VT 25/1800Z 25.0N 111.0W 30 KT...INLAND
120HR VT 26/1800Z 26.0N 110.5W 25 KT

$$
FORECASTER MAINELLI

[cycloneye]

TCDEP2
TROPICAL STORM IVO DISCUSSION NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP122007
800 PM PDT FRI SEP 21 2007

THE CONVECTIVE PATTERN ASSOCIATED WITH IVO HAS RAPIDLY DETERIORATED
OVER THE PAST SEVERAL HOURS WITH THE FORMATION OF A SHARP WESTERN
EDGE AND WARMING CLOUD TOP TEMPERATURES...LIKELY DUE TO INCREASING
SOUTHWESTERLY SHEAR. A FORTUITOUS 0028 UTC SSM/I PASS INDICATED
THAT THE LOW-LEVEL CENTER IS LOCATED WELL TO THE SOUTHWEST OF THE
DEEPEST CONVECTION AND THE INITIAL INTENSITY IS SET AT 55 KT IN
ACCORDANCE WITH A DROP IN T-NUMBERS...BUT THIS ESTIMATE IS PROBABLY
GENEROUS.

IVO IS STILL MOVING RATHER SLOWLY BUT THE SSM/I PASS SUGGESTS THAT
THE SYSTEM HAS TAKEN A SLIGHT TURN TO THE RIGHT OF THE EXTRAPOLATED
TRACK...WITH AN INITIAL MOTION OF 030/5. MODEL GUIDANCE REMAINS
SPLIT IN TWO CAMPS REGARDING THE FORECAST TRACK OF IVO. THE UKMET
AND NOGAPS MODELS REMAIN THE NORTHERN OUTLIERS BY MOVING A DEEP
TROPICAL SYSTEM ACROSS THE SOUTHERN PART OF BAJA CALIFORNIA IN
ABOUT 36-48 HOURS. HOWEVER...CONSIDERING THAT VERTICAL SHEAR HAS
ALREADY BECOME A MAJOR FACTOR IN THE WEAKENING OF IVO...THE
GUIDANCE PROVIDED BY THE GFS...ECMWF...AND GFDL MODELS APPEAR MORE
REASONABLE AT THIS TIME. THESE MODELS MOVE THE SHEARED MID-LEVEL
CIRCULATION OF IVO TO THE NORTHEAST ACROSS BAJA WITH THE LOW-LEVEL
CIRCULATION TURNING EAST AND STAYING SOUTH OF BAJA...POSSIBLY
DISSIPATING IN 3-4 DAYS. THEREFORE...THE OFFICIAL FORECAST IS
ADJUSTED TOWARD THE SOUTHERN CLUSTER OF MODELS AND SHOWS VERY SLOW
MOTION AT DAYS 4 AND 5.

THE INTENSITY FORECAST SHOWS A GRADUAL WEAKENING THROUGH THE
FORECAST PERIOD BUT IS NOT AS FAST AS SHIPS GUIDANCE...JUST IN CASE
THE SYSTEM CONTINUES TO GENERATE CONVECTION AS IT MOVES TOWARDS
BAJA. IF THE SHEAR REALLY IS MAKING A KNOCK-OUT PUNCH...WHICH
APPEARS POSSIBLE GIVEN THE SATELLITE REPRESENTATION...THEN IVO
WOULD WEAKEN FASTER THAN INDICATED IN THE OFFICIAL FORECAST.

ALTHOUGH IVO IS EXPECTED TO WEAKEN AS IT APPROACHES SOUTHERN BAJA
CALIFORNIA...TROPICAL STORM WATCHES MAY BE REQUIRED TOMORROW.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/0300Z 20.4N 113.1W 55 KT
12HR VT 22/1200Z 21.2N 112.8W 50 KT
24HR VT 23/0000Z 22.0N 112.3W 45 KT
36HR VT 23/1200Z 22.6N 111.8W 40 KT
48HR VT 24/0000Z 23.1N 111.3W 35 KT
72HR VT 25/0000Z 24.2N 110.3W 25 KT...INLAND
96HR VT 26/0000Z 24.5N 110.0W 25 KT
120HR VT 27/0000Z 25.0N 109.5W 20 KT...REMNANT LOW

$$
FORECASTER BERG/BLAKE

[brunota2003]

Amazing just how quickly it fell apart.

[Epsilon_Fan]

talk about the definition of the word "poof"

[Chacor]

Indeed.