Igor an impressive Cat 4; 92L running out of time to develop; Julia forms
There are few sights in the natural world more impressive than a hurricane near maximum intensity. Hurricane Igor certainly fits that description this morning, as it flirts with Category 5 strength in the Central Atlantic. Igor's rapid intensification burst brought the mighty hurricane's winds to 150 mph, just shy of the 156 mph threshold for Category 5 status. Igor is the strongest hurricane in the Atlantic in three years. The last hurricane stronger that Igor was Category 5 Hurricane Felix of 2007.
Figure 1. Morning satellite image of Igor.
Intensity forecast for Igor
Wind shear is low, 5 - 10 knots, and is expected to remain low for the next four days. Waters are warm, 28.5°C, and will warm to 29°C by Wednesday. Igor has moistened its environment enough to keep the dry air of the Saharan Air Layer (SAL) at bay. These conditions should allow Igor to remain at major hurricane status for the next four days. The hurricane will probably undergo one of the usual eyewall replacement cycles intense hurricanes commonly have, where the eyewall collapses and a new eyewall forms from an outer spiral band. This will weaken the hurricane by 10 - 20 mph when it occurs, but Igor will probably regain its lost intensity when the cycle completes. There's no evidence that an eyewall replacement cycle is imminent today, so Igor could potentially strengthen a bit more. However, I believe Igor has peaked, and will not reach Category 5 status today. By Saturday, when Igor should be nearing Bermuda, the trough of low pressure steering Igor northwestwards should bring moderate wind shear of 10 - 20 knots to the storm, weakening it.
Track forecast for Igor
The track forecast for Igor remains unchanged. Igor will move west under the influence of a strong ridge of high pressure until Tuesday morning, then turn more to the west-northwest then northwest in response to the steering influence of a broad trough of low pressure moving across the Western Atlantic on Tuesday and Wednesday. This should allow Igor to pass several hundred miles to the northeast of the Lesser Antilles. In the longer range, Igor appears likely to be a threat to Bermuda, and that island can expect tropical storm force winds as early as Friday. Igor does have a small chance of making landfall on the U.S. East Coast or Canada. Climatology shows that about 15% of all tropical cyclones that have existed at Igor's current position have gone on to hit the U.S. East Coast; these odds are about 10% for Bermuda and 10% for Canada. The forecast steering pattern for the period 5 - 10 days from now from the ECMWF and GFS models shows a continuation of the pattern we've seen all hurricane season, with regular strong troughs of low pressure moving off the U.S. East Coast. This pattern favors Igor eventually recurving out to sea without hitting the U.S. or Canada. While the trough expected to recurve Igor out to sea is not as sharp as the troughs that recurved Danielle, Earl, and Fiona, it should still be strong enough to keep Igor from hitting the U.S. However, Newfoundland, Canada could see a close pass. An examination of the tracks of the ten major September hurricanes that have passed closest to Igor's current location (Figure 2) reveals that one of these hurricanes went on to hit the Bahamas and Florida as a Category 2 storm, and another hit Newfoundland as a Category 1 storm. The other eight missed land. One wild card may be the intensification of Julia behind Igor. If Julia develops into a hurricane and moves close to Igor, as some of the models are suggesting, the two hurricanes could interact, affecting the track of Igor unpredictable ways. However, it currently appears the Julia will be much weaker than Igor, and will probably have little impact on her big brother's track.
Figure 2. Historical plot of the tracks of the ten major September hurricanes that have passed closest to Igor's current location.
Caribbean disturbance 92L
Tropical disturbance (92L) over the Central Caribbean, centered about 100 miles south of Jamaica, has changed little over the past day. The storm remains a threat to develop into a tropical depression, but time is running out for it to do so. Satellite loops this morning do not show a surface circulation, but 92L does have a moderate area of intense disorganized thunderstorms that are bringing heavy rain to Jamaica this morning. Kingston, Jamaica has picked up 0.67" of rain thus far this morning from 92L.
Figure 3. Morning satellite image of 92L.
Forecast for 92L
Wind shear over 92L is low, 5 - 10 knots, and is expected to remain low to moderate for the next five days. The waters beneath are hot, 29.8°C, and these warm waters extend to great depth. Water vapor satellite loops show a large area of dry air lies to the north and west of 92L, and this dry air has been interfering with development of 92L. NHC is putting the odds of 92L developing into a tropical depression by Wednesday at 40%. Given the current disorganized state of 92L, it would be difficult for it to intensify quickly enough to become any stronger than a tropical storm with 50 mph winds by Wednesday, when it will move over Belize and Mexico's Yucatan Peninsula. Once 92L crosses the Yucatan, the ridge of high pressure steering it is expected to remain in place, forcing 92L to a second landfall in Mexico several hundred miles south of the Texas border. A Hurricane Hunter aircraft is scheduled to investigate 92L this afternoon.
Julia
Tropical Storm Julia formed between the Cape Verdes Islands and coast of Africa yesterday, bringing some heavy rain squalls and gusty winds to the Cape Verdes, but no sustained winds of tropical storm force. Julia is headed northwest, out to sea, and it is unlikely that this storm will trouble any land areas . Shear is low enough over the next few days to allow Julia to become a hurricane, but shear will rise sharply 4 - 5 days from now, limiting the potential for Julia to become a major hurricane.
Elsewhere in the tropics
The NOGAPS model is calling for a new tropical depression to form off the coast of Africa 6 - 7 days from now.
Next post
I'll have a new post Tuesday morning.
Jeff Masters
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 — Blog Index
NOAA2 WXWXA 92L3 HDOB 31 20100913
141330 1613N 07829W 6437 03851 0079 +067 +032 024020 021 021 003 03
141400 1611N 07829W 6443 03841 0076 +068 +026 014017 018 010 002 03
141430 1610N 07827W 6441 03848 0078 +067 +033 014016 018 027 003 03
141500 1608N 07825W 6440 03843 0079 +063 +053 019017 018 037 005 03
141530 1607N 07824W 6439 03847 0077 +063 +060 005016 017 040 011 00
141600 1605N 07822W 6442 03841 0080 +063 +045 008018 019 038 004 00
141630 1604N 07820W 6441 03843 0083 +061 +048 012015 018 035 003 00
141700 1602N 07818W 6440 03845 0084 +061 +049 025016 017 035 008 00
141730 1601N 07817W 6439 03847 //// +061 //// 044010 014 036 013 25
141800 1600N 07815W 6410 03884 //// +056 //// 060014 018 /// /// 25
141830 1600N 07813W 6436 03849 //// +059 //// 080010 011 /// /// 25
141900 1601N 07811W 6437 03848 //// +060 //// 045009 011 027 006 21
141930 1603N 07809W 6423 03869 //// +055 //// 052009 013 030 008 21
142000 1604N 07808W 6427 03864 //// +059 //// 007019 021 032 008 21
142030 1605N 07806W 6425 03866 //// +061 //// 023016 019 033 006 21
142100 1606N 07804W 6430 03861 0076 +064 +062 010015 018 030 006 00
142130 1607N 07802W 6441 03846 0085 +059 +064 009009 011 032 006 00
142200 1608N 07800W 6436 03855 //// +054 //// 008005 006 032 007 21
142230 1609N 07759W 6433 03859 //// +060 //// 037013 015 028 006 21
142300 1610N 07757W 6424 03869 //// +055 //// 028016 017 027 005 21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
1500 UTC MON SEP 13 2010
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.
HURRICANE CENTER LOCATED NEAR 17.5N 49.7W AT 13/1500Z
POSITION ACCURATE WITHIN 10 NM
PRESENT MOVEMENT TOWARD THE WEST OR 265 DEGREES AT 9 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 933 MB
EYE DIAMETER 20 NM
MAX SUSTAINED WINDS 130 KT WITH GUSTS TO 160 KT.
64 KT....... 40NE 35SE 30SW 40NW.
50 KT....... 80NE 60SE 50SW 80NW.
34 KT.......150NE 140SE 100SW 130NW.
12 FT SEAS..300NE 180SE 180SW 300NW.
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 17.5N 49.7W AT 13/1500Z
AT 13/1200Z CENTER WAS LOCATED NEAR 17.6N 49.2W
FORECAST VALID 14/0000Z 17.9N 50.8W
MAX WIND 135 KT...GUSTS 165 KT.
64 KT... 40NE 35SE 35SW 40NW.
50 KT... 80NE 65SE 55SW 80NW.
34 KT...160NE 150SE 110SW 130NW.
FORECAST VALID 14/1200Z 18.7N 52.3W
MAX WIND 130 KT...GUSTS 160 KT.
64 KT... 45NE 40SE 40SW 45NW.
50 KT... 90NE 75SE 60SW 80NW.
34 KT...170NE 160SE 110SW 140NW.
FORECAST VALID 15/0000Z 19.5N 53.7W
MAX WIND 130 KT...GUSTS 160 KT.
64 KT... 50NE 45SE 40SW 45NW.
50 KT... 90NE 75SE 60SW 80NW.
34 KT...180NE 160SE 110SW 140NW.
FORECAST VALID 15/1200Z 20.6N 55.2W
MAX WIND 125 KT...GUSTS 155 KT.
50 KT... 90NE 75SE 65SW 80NW.
34 KT...180NE 160SE 110SW 140NW.
FORECAST VALID 16/1200Z 23.0N 58.0W
MAX WIND 115 KT...GUSTS 140 KT.
50 KT...100NE 80SE 75SW 90NW.
34 KT...210NE 180SE 130SW 160NW.
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 200 NM
ON DAY 4 AND 250 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY
OUTLOOK VALID 17/1200Z 25.5N 60.5W
MAX WIND 110 KT...GUSTS 135 KT.
OUTLOOK VALID 18/1200Z 29.0N 63.5W
MAX WIND 100 KT...GUSTS 120 KT.
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 17.5N 49.7W
NEXT ADVISORY AT 13/2100Z
$$
FORECASTER BRENNAN
NNNN
It doesn't matter if that trough is flattening out. This is what is supposed to happen. The troughs don't steer hurricanes. The troughs weaken the subtropical ridge and provides the weakness. Its cause and effect. The succesive troughs in Igor's case "causes" the subtropical ridge to weaken and this "effects" Igor by following the path of least resistance through the weakness.
Okay, I see the high. Where do you think it's going to start turning? Obviously west of the NHC track, yes?
Haha...I concede the point...DJ 1 SJ 0 Nice ;)
Anyone know what the fascination is with letting everyone know that you "poof" someone? I don't get it.
Nice band developing on the southern side.
The Advisory just came out and I will recalculate the new numbers
I would LOVE to be on a plane in that eye! Must be an awsome sight
FUNKtop
Shhhh! You aren't supposed to notice that!
My blog update from late last night.
Right, I think I understand that. But, if a trof doesn't get deep enough, lifts out and away too quickly and another high moves east then it may not weaken and can actually block the storm from moving north. Is that correct?
Me three
You can see it clearly in the track that shows where he would go if he continued on his current path. It takes him South West. I think it was Orca that posted the graphic.
Not sure about landfall with Igor, but a very close call, that I see. It's not psychotic, just looking at the pattern. Go ahead and wish it out to sea, I hope you get your wish, nobody wants a hurricane in their backyard. Right now it is what it is, Igor moving west and passing a tad south of the forecast point that starts turning the storm north, which apparently Igor doesn't want to do.
Bermuda really has to watch this. That 5 day cone will make some nervous.
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
1100 AM AST MON SEP 13 2010
IGOR CONTINUES TO HAVE A DISTINCT EYE SURROUNDED BY TOPS OF -60C TO
-70C. DVORAK CLASSIFICATIONS FROM TAFB AND SAB WERE 6.5...AND THE
INITIAL INTENSITY REMAINS 130 KT. THE UW-CIMSS SECONDARY EYEWALL
FORMATION INDEX STRONGLY SUGGESTS THAT A SECONDARY EYEWALL WILL
FORM IN THE NEXT DAY OR TWO...AND THIS WILL LIKELY RESULT IN SOME
SHORT TERM INTENSITY FLUCTUATIONS THAT ARE NOT REPRESENTED IN THE
OFFICIAL FORECAST. ON LONGER TIME SCALES...ALL OF THE INTENSITY
GUIDANCE SUGGESTS THAT IGOR IS NEAR PEAK INTENSITY...AND SHOW
GRADUAL WEAKENING THROUGH THE PERIOD. HOWEVER...SINCE THE CYCLONE
REMAINS IN WHAT APPEARS TO BE AN IDEAL ENVIRONMENT FOR THE NEXT 72
HOURS...THE OFFICIAL FORECAST IS ADJUSTED ONLY SLIGHTLY DOWNWARD
THROUGH THAT TIME. AT DAYS 4 AND 5...VERTICAL SHEAR MAY BEGIN TO
INCREASE OVER THE HURRICANE...HOWEVER...THIS INCREASE WILL BE
SENSITIVE TO THE VERY UNCERTAIN TRACK FORECAST AT THOSE TIME
RANGES. THEREFORE...AT THOSE TIMES THE OFFICIAL FORECAST IS CLOSE
TO OR A LITTLE ABOVE THE STRONGEST MODEL...THE SHIPS.
THE INITIAL MOTION ESTIMATE IS 265/9 KNOTS...A LITTLE SLOWER THAN
BEFORE...AND A BIT SOUTH OF THE PREVIOUS FORECAST. MOST OF THE
GUIDANCE...WITH THE EXCEPTION OF THE UKMET...SHOWS IGOR TURNING
TOWARD THE WEST-NORTHWEST BY TONIGHT AND THEN TURNING NORTHWESTWARD
BY 48 HOURS AS IT MOVES INTO A LARGE BREAK IN THE SUBTROPICAL
RIDGE. THE OFFICIAL FORECAST IS A LITTLE SOUTH OF THE PREVIOUS ONE
THROUGH 12 HOURS GIVEN THE INITIAL POSITION AND MOTION. FROM 12
THROUGH 48 HOURS THE OFFICIAL FORECAST IS SIMILAR TO BUT A LITTLE
SLOWER THAN THE PREVIOUS PACKAGE AND TRENDS TOWARD THE TVCN
CONSENSUS MODEL FORWARD SPEED. AT 72 HOURS AND BEYOND THERE IS
CONSIDERABLE UNCERTAINTY WITH THE EVOLUTION OF THE LARGE-SCALE FLOW
AND THE TRACK OF IGOR. THE ECMWF AND UKMET SHOW MORE MID-LEVEL
RIDGING NORTH AND NORTHEAST OF IGOR OVER THE CENTRAL ATLANTIC AND
MOVE IGOR SLOWER AND FARTHER SOUTH THAN THE REST OF THE GUIDANCE AT
DAYS 3 THROUGH 5. THE GFS...GFDL...AND GFDN KEEP THIS RIDGE FARTHER
EAST AND ALLOW IGOR TO GAIN MORE LATITUDE AND RECURVE AHEAD OF A
LONGWAVE TROUGH SITUATED OFFSHORE OF THE NORTHEASTERN UNITED
STATES. THE NOGAPS AND HWRF ARE BETWEEN THESE TWO CAMPS AND SHOW A
NORTHWESTWARD MOTION AT DAY 5. GIVEN THE INCREASING SPREAD OF THE
GUIDANCE LATE IN THE PERIOD...THE OFFICIAL FORECAST IS SIMPLY AN
UPDATE OF THE PREVIOUS ADVISORY AT THESE TIMES AND IS OF LOWER
CONFIDENCE THAN NORMAL. THE NHC TRACK IS CLOSE TO THE NOGAPS AND
WELL TO THE NORTH OF THE UKMET AND ECMWF AT THE END OF THE PERIOD.
FORECAST POSITIONS AND MAX WINDS
INITIAL 13/1500Z 17.5N 49.7W 130 KT
12HR VT 14/0000Z 17.9N 50.8W 135 KT
24HR VT 14/1200Z 18.7N 52.3W 130 KT
36HR VT 15/0000Z 19.5N 53.7W 130 KT
48HR VT 15/1200Z 20.6N 55.2W 125 KT
72HR VT 16/1200Z 23.0N 58.0W 115 KT
96HR VT 17/1200Z 25.5N 60.5W 110 KT
120HR VT 18/1200Z 29.0N 63.5W 100 KT
$$
FORECASTER BRENNAN
Hey Ike. NHC Believes the track will begin going just north of 270 within 12 hours and the curve sharpening betw 48-60 hours.
Interesting and appreciate you posting. Thanks!
Like the weak high pressure shown over Igor here? Pretty obvious that the Azores high has been jaded E all season and has allowed the troughs to erode the weaker western edge pretty easily. Have no reason to believe that won't happen again. And I didn't even stay at an HIE last night.
The first trough, which Igor is running south of is keeping him on a west movement with some south wobbles.
And, I think I disagree that after an EWRC he will return to his present peak wind velocity. An available energy vs. kinetic energy imbalance thing as a larger storm footprint has so much more ACE. (Though, larger eyewall area = larger inflow area, but still doesn't seem equivalent for some reason).
There'll be some weakening due to EWRC at some point, though.
However, it is indeed very likely it'll surpass Earl. Nobody really thought otherwise. It is whether it'd surpass Ike in ACE. Still thinking it'll fall just short.
I think it is also, but in the atcf, it says this:
## ANNULAR HURRICANE INDEX (AHI) AL112010 IGOR 09/13/10 12 UTC ##
## PASSED SCREENING STEP, MIGHT BE ANNULAR, CALCULATE AHI FROM DISCRIMINANT ANALYSIS ##
## AHI= 1 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
## ANNULAR INDEX RAN NORMALLY
So it is marginally annular.
These WSW jogs are getting to be a little interesting...
It will also be the highest since Comra
It will be also the highest since comrade IVAN
One day they might have sat technology that will allow us to do just that =)
off topic.....
Anyone know why NYC area is getting buzzed by F-16s right now? They are taking off from Newark Liberty and heading Northeast at a rapid pace. 5th one so far today. Then they make a low (200 ft?) pass at high speed again.
Viewing: 151 - 201
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 — Blog Index