Tropical Storm Leslie hits Newfoundland; TD 14 forms
Tropical Storm Leslie zoomed ashore over Newfoundland this morning near 8 am EDT, traveling with a forward speed of 40 mph. Leslie brought sustained winds to the capital of St. Johns of 58 mph, gusting to 82 mph, at 10:30 am local time. At least three other stations in Newfoundland recorded gusts over hurricane force: Cape Pine (85 mph), Bonavista (77 mph), and Argentia (74 mph). Damage to buildings has been reported in St. Johns, and the storm has knocked out power to much of Southeast Newfoundland, including the capital. Leslie's tropical moisture collided with the cold front drawing the storm to the north, resulting in heavy rains over Nova Scotia in excess of 4 inches, which caused considerable flooding of homes and streets. Overall, though, the damage to Canada appears to be far less than that of Hurricane Igor, which hit Newfoundland as a Category 1 hurricane in 2010, causing $200 million in damage. Leslie has now transitioned to a powerful extratropical storm, and will bring heavy rains to Iceland on Thursday, and to Scotland on Friday.
Figure 1. Tropical Storm Leslie as it crossed Newfoundland at 9:46 am EDT September 11, 2012. At the time, Leslie had top winds of 70 mph. The cloud pattern of Leslie looks more extratropical than tropical, and Leslie was no longer a tropical storm at this time. Tropical Storm Michael is visible at lower right, as a tight swirl of low clouds.
Hurricane Michael dying
The longest-lived hurricane of the 2012 Atlantic hurricane season was Michael, which attained hurricane status at 11 pm EDT September 5 and finally weakened to a tropical storm at 5 am EDT this morning. Satellite loops show that Michael has lost almost all of its heavy thunderstorms, and is racing to the northeast over colder waters. Michael will likely be declared dead later today.
Tropical Depression 14 forms
Tropical Depression Fourteen has formed midway between Africa and the Lesser Antilles Islands, from a tropical wave that emerged off the coast of Africa on Friday. The models unanimously predict that TD 14 recurve to the north well east of the Lesser Antilles Islands later this week, on a track that would likely keep this storm far out at sea away from any land areas. TD 14 is in a low-shear environment favorable for strengthening, and will likely become Tropical Storm Nadine by Wednesday.
Elsewhere in the Atlantic
The ECMWF model predicts that the cold front that swept off the U.S. East Coast Monday will leave a trough of low pressure over the ocean which could serve as the focus for development of a tropical or subtropical depression several hundred miles off the coast of North Carolina late this week.
Figure 2. Visible NOAA GOES-7 satellite image of Hurricane Iniki just before landfall in Hawaii at 8:01 pm EDT September 11, 1992. Iniki completed a “clean sweep” of National Weather Service offices responsible for issuing hurricane warnings. The National Hurricane Center in Coral Gables, Florida (Hurricane Andrew), the Joint Typhoon Warning Center in Guam (Typhoon Omar), and the Central Pacific Hurricane Center in Honolulu, Hawaii (Hurricane Iniki) were all struck by strong hurricanes within a 2-month span in 1992. Image credit: NOAA Environmental Visualization Lab.
20th anniversary of Hurricane Iniki
Twenty years ago today, Hurricane Iniki, the most powerful hurricane on record to strike the state of Hawaii, made landfall on the island of Kauai as a Category 4 storm with sustained winds of 145 mph and gusts up to 175 mph. Iniki brought storm tides of 4.5 - 6 feet (1.4 - 1.8 m) to Kauai, with high water marks of up to 18 feet (5.5 m) being measured due to large waves on top of the surge. Waves up to 35 feet (10.5 m) battered the southern coastline for several hours, causing a debris line of more than 800 feet (250 m) inland. The hurricane's high winds did incredible damage to structures on the island--5,152 homes were severely damaged, and some parts of the island were without power for three months. Iniki's $3 billion damage (2012 dollars) made the hurricane the second costliest Eastern Pacific hurricane, trailing Hurricane Paul, which made landfall in Mexico in 1982. Iniki holds the Eastern Pacific record for lowest pressure for a landfalling hurricane--945 mb (27.91").
Jeff Masters
Reader Comments
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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm
----- Current Analysis -----
Date : 12 SEP 2012 Time : 131500 UTC
Lat : 19:05:23 N Lon : 47:30:18 W
CI# /Pressure/ Vmax
3.9 / 989.5mb/ 63.0kt
Final T# Adj T# Raw T#
3.9 4.3 5.1
Estimated radius of max. wind based on IR :N/A km
Center Temp : -29.2C Cloud Region Temp : -57.5C
Scene Type : EYE
Positioning Method : FORECAST INTERPOLATION
Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC
Tno/CI Rules : Constraint Limits : 0.5T/hour
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 40km
- Environmental MSLP : 1013mb
Raw T# now up to 5.1.
But Kadena will get a real hurting.
If the track moves just a tiny bit to the left, it will be even worse. There was Bolaven a few weeks ago, then Tembin. I can't believe the latest typhoons are all heading to the Korean Peninsula.
I am worried about this storm as I live in Seoul. The strength of this storm is expected to be very strong. Who knows, maybe it might be stronger than Bolaven.
By the way, the effects on the Seoul Metropolitan Area were not severe, so people here are saying they prepared for nothing. On the other hand, the southern provinces are suffering from the aftermath of two consecutive typhoons. It would be a nightmare for them if a third typhoon made landfall, especially since a 3-day holiday starts in about two weeks.
They are still getting dvorak numbers on ex-Leslie. She's been steady at 25kts for wind speed, she should stay to the right of you so I'd say no higher than that. Your local forecast concurs.
Does anybody have an instability graph?
Link WV GOM
Isaac had higher max IKE value than any other storm this year.
Isaac had higher HSI rating than either Leslie or Michael ever achieved.
heck, Isaac had higher IKE value than Andrew or Charlie, and much higher IKE values and HSI values than several category 2 and 3 landfalls from the 2004 through 2008 seasons.
Isaac's maximum storm surge was in the middle of the old "Category 4" range on the SS scale.
Isaac produced widespread storm surges in the middle of the old "Category 3" range on the SS scale.
I calculated that Isaac at landfall probably ranks as a 20 on the Hurricane Severity Index(unofficially).
Gustav U.S. landfall is a 20 on HSI, officially, as a 110mph maximum category 2 on SS scale.
Dennis(05) landfall ranks as an 18 on the HSI, officially. It was a 125mph, Cat 3 at the time.
Using Andrew's size parameters, and comparing to Michael at peak intensity, I determined that Michael got either 7 or 8 points for size at maximum intensity, and 11 points for intensity itself.
So I gave category 3 Michael an 18 or 19, unofficially, on the HSI.
In reality, the "strongest" or "most severe" storm to form so far this year was in fact Isaac, and the SS wind scale is the only scale I can think of that does not rank it so.
The old SS storm surge scale, which was never used as it was intended to be used, ranks Isaac as a category 4 hurricane.
Date : 12 SEP 2012 Time : 134500 UTC
Lat : 19:09:05 N Lon : 47:36:43 W
CI# /Pressure/ Vmax
4.0 / 988.1mb/ 65.0kt
Final T# Adj T# Raw T#
4.0 4.3 5.0
Estimated radius of max. wind based on IR :N/A km
Center Temp : -30.0C Cloud Region Temp : -57.2C
Scene Type : EYE
The data from CIMSS says that we've got Hurricane Nadine - and that she's got a readily discernible eye. And the raw T holds steady around 5 for the second straight reading, suggesting that Nadine may already be a Category 2 storm.
The only question is whether NHC will hold at 60kts, or take Nadine right there.
11:00 AM AST Wed Sep 12
Location: 19.1°N 47.6°W
Moving: WNW at 15 mph
Min pressure: 997 mb
Max sustained: 60 mph
:) I haven't always lived in Iceland. I grew up in Houston, and my family still lives there, so even when I moved away elsewhere in the US, I kept up on following the tropics. But I completely fell in love with Iceland when here for a couple weeks as a tourist, to the point that I started learning the language, found a job, and moved. :) If I had to sum up Iceland in a brief sentence, it'd be "A stunningly beautiful artists'-colony island that exudes raw power."
Both tornadoes and lightning are very rare in Iceland, but they do happen. We pretty much never get the hot, humid air that you normally need to kick up tornadoes. I've never once felt any weather here that I would describe as "hot and humid". At best, "warm". I think relative humidity is high, but you don't notice because the weather is always cool (although seldom "cold" like winters in Canada, Alaska, parts of the northern great plains, etc).
Now, we do get some other things that I never saw before in the US. We get both polar stratospheric and noctilucent clouds, as well as tons of other weird cloud structures (some of the clouds out my window are forming these weird spindly tendrils, for example). Lots of formations happen here that suggest frequent and significant changes of the atmosphere in thin horizontal layers. Also in the winter, spring and fall we sometimes get a type of ice pellet precipitation that I never experienced in the US - they're pellets, not flakes, but they're still light and fluffy, not hard and dense. Lastly, weather here is famously changeable, esp. in the spring. I know people in the US like to joke, "If you don't like the weather, just wait 5 minutes", but here it really can be like that regularly in certain times of year. It's still crazy to watch a single storm cycle through windspeeds from calm to 30m/s or so and precipitation between none, snow, rain, hail, and ice pellets, and the cloud cover between sun with rainbows and full clouds, with a change happening every 5 minutes or so, and the different parameters unconnected with each other, for a couple hours on end.
That said, summer this year was just unbelievably lovely. Tons of glacial melt, sadly (we're losing them fast), but clear skies and wonderful temperatures.
They already know about this.
HSI is the ranking system invented by Impact Weather. While not perfect, it's better than the SS wind scale alone.
HSI PDF paper from Impact Weather
Although one flaw with this paper is it did not lay out their specific definitions for how to determine the size parameters, so I used encyclopedias to figure that out and use as proxies when doing my "unofficial" rankings for Isaac, Leslie, and Michael. Michael was easiest because it was actually no larger than Andrew in size, and possibly one point smaller, which I could verify using data from Colorado state's site.
So I didn't just "make up" my numbers. I followed their rules and used close proxy storms to determine the size scores that I came up with.
Personally, I think the HSI needs to be enhanced by squaring the left side and dividing by 625 to renormalize, because it is the AREA of the hurricane that does damage, not the radius alone, and area is a function of radius squared.
Nevertheless, the HSI for most storm comparisons is more in line with IKE values than the SS wind scale alone, but it is not perfect, as there are some significant deviations.
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012
1100 AM AST WED SEP 12 2012
THE SATELLITE PRESENTATION OF NADINE SHOWS A CONTINUED INCREASE IN
ORGANIZATION...WITH A DEVELOPING CENTRAL DENSE OVERCAST AND
CONVECTIVE BANDING FEATURES IN ALL QUADRANTS. DVORAK INTENSITY
ESTIMATES ARE 55 KT FROM SAB AND 45 KT FROM TAFB. USING A BLEND OF
THESE INTENSITY ESTIMATES...THE INITIAL INTENSITY IS SET TO 50 KT.
ANIMATION OF WATER VAPOR IMAGERY SHOWS WEAK SHEAR OVER NADINE WITH
A WELL-DEFINED UPPER-LEVEL OUTFLOW PATTERN. A BROAD TROUGH WELL TO
THE NORTHEAST OF THE STORM MAY BE ASSISTING THE OUTFLOW TO THE
NORTH AND EAST. NADINE IS EXPECTED TO REMAIN IN A FAVORABLE UPPER-
LEVEL WIND ENVIRONMENT FOR THE NEXT COUPLE OF DAYS. HOWEVER...FROM
72 HOURS AND BEYOND NADINE IS EXPECTED TO ENCOUNTER A BELT OF
STRONG WESTERLIES TO THE NORTH OF THE SUBTROPICAL RIDGE...AND THE
LGEM GUIDANCE SHOWS WESTERLY SHEAR INCREASING TO 25-30 KT DURING
THIS TIME FRAME. THE NHC INTENSITY FORECAST IS IN REASONABLE
AGREEMENT WITH THE LATEST LGEM AND CONSENSUS MODEL GUIDANCE. IT
SHOULD BE NOTED THAT THE SHIPS RI INDEX IS STILL SHOWING A
SIGNIFICANT PROBABILITY OF RAPID INTENSIFICATION DURING THE NEXT 24
HOURS...SO THE OFFICIAL INTENSITY FORECAST FOR THE NEXT DAY OR TWO
COULD BE CONSERVATIVE.
CENTER FIXES SHOW A MOTION BETWEEN WEST-NORTHWEST AND NORTHWEST...
AND THE CURRENT MOTION ESTIMATE IS 300/13. NADINE CONTINUES TO
HEAD TOWARD A BREAK IN THE SUBTROPICAL RIDGE CAUSED BY A MID- TO
UPPER-LEVEL LOW TO ITS WEST. THE OFFICIAL FORECAST IS SIMILAR TO
THE PREVIOUS ONE AND TAKES THE TROPICAL CYCLONE AROUND THE WESTERN
PERIPHERY OF A SUBTROPICAL ANTICYCLONE FOR THE NEXT 2-3 DAYS.
NADINE IS EXPECTED TO MOVE INTO THE WESTERLIES BEYOND 72 HOURS...SO
THE OFFICIAL FORECAST SHOWS A TURN TOWARDS THE NORTHEAST AND
EAST-NORTHEAST DURING THE LATTER PART OF THE FORECAST PERIOD. THE
CURRENT NHC TRACK LIES BETWEEN THE SLOWER ECMWF...AND ITS ENSEMBLE
MEAN...AND THE QUICKER 0600 UTC GFS SOLUTION.
THE WIND RADII HAVE BEEN ADJUSTED BASED ON A 1215 UTC ASCAT
OVERPASS...WHICH SAMPLED THE EASTERN SIDE OF THE CIRCULATION AND
REVEALED A LARGER TROPICAL CYCLONE THAN PREVIOUSLY ESTIMATED.
FORECAST POSITIONS AND MAX WINDS
INIT 12/1500Z 19.1N 47.6W 50 KT 60 MPH
12H 13/0000Z 20.3N 49.2W 60 KT 70 MPH
24H 13/1200Z 22.1N 51.3W 70 KT 80 MPH
36H 14/0000Z 24.1N 52.9W 75 KT 85 MPH
48H 14/1200Z 26.3N 53.8W 75 KT 85 MPH
72H 15/1200Z 30.0N 52.5W 75 KT 85 MPH
96H 16/1200Z 32.5N 49.0W 70 KT 80 MPH
120H 17/1200Z 34.5N 43.5W 65 KT 75 MPH
$$
FORECASTER ROTH/PASCH
TROPICAL DEPRESSION ELEVEN-E DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112012
800 AM PDT WED SEP 12 2012
THE LOW PRESSURE AREA THAT HAS BEEN MOVING SLOWLY WESTWARD SOUTH OF
THE COAST OF MEXICO HAS DEVELOPED ENOUGH ORGANIZED CONVECTION TO BE
CLASSIFIED AS A TROPICAL DEPRESSION. THE POSITION OF THE LOW-LEVEL
CENTER IS UNCERTAIN...AND IT IS A BLEND BETWEEN ASCAT DATA HOURS
AGO...AN AMSU-B PASS AT 1002 UTC...AND RECENT VISIBLE PICTURES.
THE CLOUD PATTERN...ALTHOUGH LARGE...DOES NOT HAVE ORGANIZED BANDING
FEATURES YET...BUT THE OUTFLOW IS BECOMING ESTABLISHED IN ALL
QUADRANTS. BOTH GLOBAL AND STATISTICAL MODELS FORECAST AN INCREASE
IN THE SHEAR FAVORING ONLY SOME STRENGTHENING DURING THE NEXT 48
HOURS. BEYOND THAT TIME...THE CIRCULATION WILL BE MOVING OVER
COOLER WATERS...AND WEAKENING SHOULD THEN BEGIN.
THE INITIAL MOTION IS ALSO UNCERTAIN...AND THE BEST ESTIMATE IS
WEST-NORTHWEST OR 300 DEGREES AT 9 KNOTS. THE DEPRESSION IS LOCATED
SOUTH OF THE SUBTROPICAL RIDGE WHICH IS FORECAST TO PERSIST. THIS
STEERING PATTERN SHOULD FAVOR A CONTINUATION OF THE WEST-NORTHWEST
MOTION THROUGH 5 DAYS WITHOUT A SIGNIFICANT CHANGE IN FORWARD
SPEED. THE OFFICIAL FORECAST IS VERY CLOSE TO THE MODEL CONSENSUS
AND HEAVILY BIASED TO THE ECMWF AND THE GFS.
FORECAST POSITIONS AND MAX WINDS
INIT 12/1500Z 16.7N 106.0W 30 KT 35 MPH
12H 13/0000Z 17.1N 107.3W 30 KT 35 MPH
24H 13/1200Z 17.7N 109.0W 35 KT 40 MPH
36H 14/0000Z 18.2N 110.5W 45 KT 50 MPH
48H 14/1200Z 19.0N 112.5W 50 KT 60 MPH
72H 15/1200Z 21.0N 117.0W 40 KT 45 MPH
96H 16/1200Z 23.0N 121.0W 30 KT 35 MPH
120H 17/1200Z 25.0N 125.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
FORECASTER AVILA
My wife and I got out a bit Sunday (I actually BBQed), but sadly, my semester for nursing school just started, which means my life consists of work (full time M-F), school (sitting in front of a computer or reading), and sometimes sleep. :(
I dont even see an eye...hmmm.
I guess itll clear out soon
4" of rain and millions in damages, would be a heavy summer shower in an expensive Miami neighborhood down here. So yes, we worry about low pressure systems developing that don't have hurricane in front of their names. 2004 and 2005 had Billions in damages and 4+ Tropical Storms with Cat 3+.
By the time they get to Canada, they have been around for a while, are moving fast, and you know they are coming. It is great to have bloggers on the ground there, sharing info.
If you had lows in the Gulf of St. Laurence spinning into Hurricanes in 24 hours, you would pay attention to them too.
That being said, it is wonderful to have Aussie, Asian?, Islander, Canadian, and Midwestern perspectives in the community.
Arent you looking forward to some rain? I can hardly wait ...ove the rain and Houston can pretty much always use it!
Date 2007
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