Category 4 Earl headed for a close brush with North Carolina

By: Dr. Jeff Masters , 3:16 PM GMT on August 31, 2010

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Powerful Category 4 Hurricane Earl is pulling away from Puerto Rico and the northern Lesser Antilles Islands, and is eyeing its next potential landfall--North Carolina's Outer Banks. Earl brought heavy rain and high winds to Puerto Rico and much of the northern Lesser Antilles yesterday, though it appears that the islands were spared major damage. One exception may be Anegada in the British Virgin Islands, population 200. The eye of Earl passed just north of Anegada at noon yesterday, and Earl's south eyewall probably brought sustained winds of 100 mph to the island. Second hardest hit was probably Anguilla. Amateur weather observer Steve Donahue at anguilla-weather.com estimated gusts of 100 mph on Anguilla; his anemometer broke at 88 mph. Winds in St. Thomas in the U.S. Virgin Islands remained above tropical storm force (39 mph) for five hours yesterday afternoon, peaking at 52 mph, gusting to 62 mph, at 4:49 pm. Heavy rains hit Puerto Rico, where radar-estimated rainfall amounts of up to 5 - 7" occurred. Earl brought waves of sixteen feet to San Juan, and waves at buoy 41043 offshore of Puerto Rico reached 31 feet early this morning.


Figure 1. Morning satellite image of Earl, taken at 10:30am EDT 8/31/10. Image credit: NASA/GSFC.


Figure 2. Radar estimated rainfall for Earl from the San Juan, Puerto Rico radar. Isolated regions of 5 - 7 " of rain occurred in three locations on Puerto Rico. The rays fanning out to east from the radar location marked with a "+" are due to mountains blocking the view of the radar.

Intensity forecast for Earl
Wind shear as diagnosed by the latest SHIPS model forecast shows a moderate 10 - 20 knots of wind shear over Earl, due to upper level winds out of the southwest from a trough of low pressure to Earl's west. This moderate shear is predicted to continue through Friday, but should not appreciably affect Earl, since the hurricane is so large and strong. Ocean temperatures are a near-record 29.5 - 30°C, and very warm waters extend to great depth, resulting in a total ocean heat content favorable for intensification. Earl is undergoing an eyewall replacement cycle, which may diminish its winds by 10 -20 mph for a day or so. However, the storm will probably regain strength after completing this cycle, and it is likely Earl will be a major Category 3 or 4 hurricane at its closest approach to North Carolina Thursday night and Friday morning. By Friday night, when Earl will be making its closest approach to New England, wind shear will rise to a high 20 - 30 knots and ocean temperatures will plunge to 20°C, resulting in considerable weakening. Earl will still probably be a Category 2 hurricane on Friday night, when it could potentially make landfall in Massachusetts. Earl is more likely to be a Category 1 hurricane on Saturday morning, when it could potentially make landfall in Maine or Nova Scotia, Canada.


Figure 3. Swath of surface winds from Earl predicted by the 2am EDT Tuesday, August 31, 2010 runs of NOAA's GFDL model (left) and HWRF model (right). Hurricane force winds (yellow colors, above 64 knots) are predicted to stay off the coast. Tropical storm force winds (light green colors, above 34 knots) are predicted to affect coastal North Carolina, Massachusetts, and Eastern Maine. Winds between 58 mph - 73 mph (dark green colors) are predicted to small portions of the coast. Image credit: Morris Bender, NOAA/GFDL.

Track forecast for Earl
The latest set of computer models runs from 2am EDT (6Z) this morning push Earl's projected track a little closer to the U.S. East Coast, and we now have two of our six reliable models predicting a U.S. landfall. The latest NOGAPS run shows Earl hitting the Outer Banks of North Carolina late Thursday night, then striking Southeast Massachusetts late Friday night, and Eastern Maine on Saturday morning. The HWRF model predicts a strike on Eastern Maine Saturday morning, but keeps Earl offshore from North Carolina and Massachusetts. None of the other computer models show Earl hitting the U.S., but several models bring Earl within 100 - 200 miles of North Carolina's Outer Banks and Southeast Massachusetts. It is likely that Earl will being a 12-hour period of heavy rain and tropical storm force winds of 39+ mph to North Carolina's Outer Banks, beginning on Thursday evening. NHC is giving Cape Hatteras a 12% chance of receiving hurricane force winds. By Friday evening, western Long Island, Rhode Island, and Southeast Massachusetts can expect a 6 - 8 hour period of heavy rain and tropical storm force winds of 39+ mph. NHC is giving Nantucket a 11% chance of receiving hurricane force winds. These odds are 4% for Boston, 6% for Providence, 5% for Eastport, Maine, and 11% for Yarmouth, Nova Scotia. The main determinant of whether Earl hits the U.S. or not is a strong trough of low pressure predicted to move off the U.S. East Coast Friday. This trough, if it develops as predicted, should be strong enough to recurve Earl out to sea. Keep in mind that the average error in position for a 3-day NHC forecast is 185 miles, which is about how far offshore Earl is predicted to be from Cape Hatteras three days from now. The average error in a 4-day forecast is 255 miles, which is about the distance Earl is expected to be from the coast of New England four days from now.

Regardless of Earl's exact track, the U.S. East Coast can expect a long period of high waves beginning on Thursday. Significant beach erosion and dangerous rip currents will be the rule, due to waves that will reach 10 - 15 feet in offshore waters. Waves from Hurricane Danielle killed two swimmers in the U.S. over the weekend and forced hundreds of water rescues along the U.S. East Coast. Earl's waves will be worse, and will likely cause millions of dollars in beach erosion damage.

Fiona
Tropical Storm Fiona is speeding west-northwest towards Hurricane Earl, but is unlikely to bring tropical storm force winds to the Lesser Antilles. Satellite loops show that heavy thunderstorm activity has increased in some of the outer bands this morning, but remains limited near the center. Wind shear is currently moderate, 10 - 15 knots, and the main impediment to development continues to be dry air associated with the Saharan Air Layer (SAL) surrounding the storm.

Forecast for Fiona
Fiona is moving quickly to the west-northwest, at about 24 mph. This means it is catching up to Earl, which is moving at 15 mph. By tonight, Fiona will be beneath Earl's upper-level outflow channel. Strong upper-level winds from Earl's upper-level outflow and a ridge of high pressure to the northwest of Fiona will bring high levels of wind shear, 20 - 30 knots, to Fiona tonight through Friday, and probably arrest the storm's development. The scenario now called for by all the models is for Fiona to be drawn into the low pressure wake of Earl and turn to the northwest. Fiona will pass to the northeast of the Lesser Antilles, and will probably not bring tropical storm force winds to the islands. Fiona should then continue to the northwest and then turn north, passing very close to Bermuda on Saturday morning. It is possible Earl could destroy Fiona through high wind shear before Saturday.


Figure 4. Morning satellite image of Fiona. High level cirrus clouds flowing out from the center of Earl as part of its upper level outflow can be seen starting to impinge upon the western side of Fiona's circulation.

Danielle is dead
Tropical Storm Danielle has succumbed to the cold North Atlantic waters, and is no longer a tropical storm.

98L
A new tropical wave (Invest 98L) moved off the coast of Africa yesterday, and is centered a few hundred miles south of the Cape Verdes Islands. Strong easterly winds from the African Monsoon are creating a moderate 10 - 20 knots of shear, and the disturbance is currently disorganized. A large area of dry air lies to the north and west of 98L, and this will interfere with development. The latest SHIPS model forecast predicts shear will remain moderate, 10 - 20 knots, for the next five days, and some slow development of 98L is possible as it moves westward at 15 mph. NHC is giving a 10% chance of this system developing into a tropical depression by Thursday, and none of the computer models develop it.


Figure 5. Morning satellite image of 98L.

A rare triple threat in the Western Pacific
Over in the Western Pacific, we have an unusual triple feature--three named storms all within 700 miles of each other. A 3-way interaction between these storms is occurring, making for a very tough forecast situation. The storm of most concern is Typhoon Kompasu, which hit Okinawa today as a Category 2 typhoon. Kompasu is expected to recurve northeastward and hit North Korea on Thursday as a Category 2 typhoon. It is unusual for a powerful typhoon to thread the tight Yellow Sea and hit North Korea, and I don't know how prepared they are for strong typhoons. Kompasu is expected to hit the most populous region of North Korea, but the country is pretty mountainous, and a significant storm surge disaster is probably unlikely. In the South China Sea, Tropical Storm Lionrock and Tropical Storm Namtheun are moving through the straights between Taiwan and China towards each other. Neither are predicted to develop into typhoons, but heavy rains are occurring in Guangdong and Fujian Provinces, further exacerbating the flood conditions China has suffered this summer.


Figure 6. An unusual triple feature over the Western Pacific--three simultaneous named storms all within 700 miles of each other. Image credit: NOAA/SSD.

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question to broadcast@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line.

Today's show will be about 45 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

I may have a short update this afternoon, once the latest models runs are available.
Jeff Masters

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Quoting sammywammybamy:


That Caller from New Orleans, Was Off Topic. He Was Asking about the Oil Affect Hurricanes.



That's just my point....how is that off topic?? It's a question regarding tropics and the oil disaster, if they have any affect on one another. It's easy to be a back seat driver...my point to you is...if you have a better question....STEP UP!!
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Quoting Floodman:


The loop current has stopped? Really? When did this happen? Being part of the thermohaline circulation that would indicate that the whole system is stopping (as they are all inter-dependent and inter-connected); why hasn't this made the headlines, given that it would indicate a collapse of the current climate regimen?

Read this article on the loop current it could cause major catostrophic crop failure. http://www.sott.net/articles/show/214379-Gulf-Loop-Current-Stalls-from-BP-Oil-Disaster-Global-Conse%2 0quences-if-Current-Fails-to-Reorganize
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Quoting mcluvincane:
Ok. The east coast looks to be safe with the latest track. Going just like the models said it would.


Safe???? You call a cat 3 bearing down on NC safe??
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Quoting angiest:


After several days of being wrong.



you talking about yourself or the models??
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Quoting ElConando:
So a Hurricane Watch for the NC coast for now. I'd expect at least some TS watches to go into effect later tonight for VA.
Our local mets. are pretty sure we will be fine. I agree,, a little breezy and VICTORY at Sea!!
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1424. angiest
Quoting mcluvincane:
Ok. The east coast looks to be safe with the latest track. Going just like the models said it would.


After several days of being wrong.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting weatherman12345:

agreed, what do you think will become of 98l


Slow to develop, but staying pretty far to the south... maybe 10 days out from effecting the islands.
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Quoting Floodman:


The loop current has stopped? Really? When did this happen? Being part of the thermohaline circulation that would indicate that the whole system is stopping (as they are all inter-dependent and inter-connected); why hasn't this made the headlines, given that it would indicate a collapse of the current climate regimen?


floodman - he is a link - this may or may not be the one posted earlier on the blog
Link
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Quoting DestinJeff:
"A DAY OR SO" is finally here!

Ok, NW motion engaged....

now the question becomes when does he get some easterly component ... east of north that is.

Time to cue the trough to the west.

Hooray! :)
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Ok. The east coast looks to be safe with the latest track. Going just like the models said it would.
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1418. angiest
Quoting ElConando:
When NHC says TS winds extend 200 miles from the center they mean by Diameter.


No I believe that is the radius.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1417. CJ5
Quoting PSLFLCaneVet:
Glad I waited for the blog to respond. Don't care to be called blind.


Sorry, I responded on up further when corrected. I mean't blind in respect to that graphic. Didn't mean to come off smart arsed.
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1416. jscs
Quoting pilotguy1:


Someone needs to be protecting the US economic interests as long as it isn't endangering people. Some would have us evacuating the entire East coast already.


Completely agree. But to tell people in Charleston, at this moment, that off the beach you won't even know there is a storm is irresponsible at this moment. As it stands, the turn to the NW sharp is a prediction... until that sharp turn, Charleston simply isn't in the clear.
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1415. Dunkman
Everyone going on about the listed change from WNW to NW...please note that the heading changed from 300 to 305. It's a start, but it's not exactly making me happy yet.
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When NHC says TS winds extend 200 miles from the center they mean by Diameter.
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98L becoming better organized despite dry air to its north.
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Link

Here is my forecast track I expect. I made it last night. Thoughts? Hurricane Earl is a dangerous Category Four Hurricane on the Saffir-Simpson scale with 135mph winds. Earl continues to move towards the WNW at around 12-13mph. Satellite imagery suggests he is encountering some SWrly wind shear but should abate within the 24 hour timeframe. I expect this, shear to abate and allow further intensification. Dry air to the northwest of Earl will make it hard to forecast for category five intensity, but I will go with the 12z GFDL and forecast a peak intensity of 150-160mph and pressure somewhere around 925-930mb at peak within the next 24 hours. Models are slowing the movement down of Earl in the 96 hour timeframe with the 12z EURO bringing Earl possibly ashore across Cape Cod, MA sometime around Saturday morning. This model is on the western side of the guidance envelope, with most model guidance in the middle of the NOGAPS (western outlier) and CMC (eastern outlier). A strong trough of low pressure will begin to provide a weakness in the strong A/B ridge extension over to the high over the SE US. It is possible that this ridge is holding stronger then anticipated likely keeping Earl initially on a WNW path with a turn to the NW expected within 12 hours. Models differ by day 3 with possible effects on the Outer Banks of NC. NOGAPS 12z run shows landfall over the region and the 12z EURO is really close as well. Right now I expect Earl to pass within 50 miles of the NC Outer Banks region providing hurricane force wind gusts as it is quite possible he could maintain category four intensity as he passes this latitude. In doing so, hurricane force wind field could expand especially since he going through an EWRC currently. Everyone from Outer Banks of NC northward to Nova Scotia, Canada needs to monitor the progress of this large and dangerous hurricane.
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Quoting EastCarolina:


Ocracoke is accessible by ferry only. Also the road between Oregon Inlet and Hatteras washes out very easily. In comparison the northern obx is easier to evacuate.


Howards Pub will be busy the next few days. Wish I was down there with them having a few cold ones! They eat these storms for lunch down there!
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1408. angiest
Quoting DestinJeff:
"A DAY OR SO" is finally here!

Ok, NW motion engaged....

now the question becomes when does he get some easterly component ... east of north that is.

Time to cue the trough to the west.


It's only taken a few days. He may still like the west side of the cone, however.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting EastCarolina:


Ocracoke will start having mandatory evacuations tomorrow at 5:00 am. An evacuation may be called for duck but it probably wont occur untill later tomorrow.


If I could chime in some advice... I'd tell my daughter and her friends to fill up their gas tanks NOW or even at midnight tonight. I'd also have them go get two plastic 5-gallon gas cans at Walmart or someplace and fill those too.

After that, they can relax. If evac is called, the lines at the pumps will be blocks long. Sometimes gas won't be available at stations along the evacuation routes for 100 miles.

I wouldn't worry about the kids if they have common sense and a full tank of gas to get out of there. Tell them not to wait, though.
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So everyone that was talking about TWC saying major shift W...Did they get you to watch? If so, they did a good job of marketing...Which reminds me I need to do some marketing homework...Arghh.
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Quoting shadoclown45:
Question For Dr. Masters-

Do you think that the loop current stoping will affect the hurricane season? - Alex


The loop current has stopped? Really? When did this happen? Being part of the thermohaline circulation that would indicate that the whole system is stopping (as they are all inter-dependent and inter-connected); why hasn't this made the headlines, given that it would indicate a collapse of the current climate regimen?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting sammywammybamy:


If You Live in North Carolina, Please Note:

HURRICANE WATCH HAS BEEN ISSUED FOR THE EAST COAST OF THE UNITED
STATES FROM NORTH OF SURF CITY TO DUCK NORTH CAROLINA...INCLUDING
THE PAMLICO AND ALBEMARLE SOUNDS.

A TROPICAL STORM WATCH HAS BEEN ISSUED FROM CAPE FEAR NORTH CAROLINA
NORTHEASTWARD TO SURF CITY.



??????? Is that a reply to my statement??
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So a Hurricane Watch for the NC coast for now. I'd expect at least some TS watches to go into effect later tonight for VA.
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Quoting dmaddox:
if it crosses 75W... watch out!!


if he was moving west as much as some commenters on here think, he would have already crossed 75W.....last night.
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Quoting jscs:


Sounds like someone with Labor Day economic interests to protect. The winds from this storm are TS force up to 100 miles from the eye.


Earl is predicted to be closer to 250 miles away from Charleston...Unless there is some majorly unforeseen shift W (which I give a .1% chance) then Earl will not have any impact on this area other huge surf.
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1393. Vero1
Thank you Dr. Masters for your broadcast update.
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1391. dmaddox
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Quoting jscs:


Sounds like someone with Labor Day economic interests to protect. The winds from this storm are TS force up to 100 miles from the eye.


Yeah, don't listen to The Man!!
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1389. dmaddox
if it crosses 75W... watch out!!
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EWRC is nearing completetion but some light shear of 10 to 20 knts from the SW will keep Earl at the high cat3 lowcat4.
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1386. jscs
Quoting Chucktown:


Just got off a conference call with NWS here in Charleston. We are not expecting anything here except for rough surf and maybe some erosion. In fact if you are not at the beach on Thursday, you will not even know there is a Cat 3/4 hurricane offshore. Sunny with highs in the 90's for the rest of the week here.


Sounds like someone with Labor Day economic interests to protect. The winds from this storm are TS force up to 100 miles from the eye.
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1385. huber
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

A HURRICANE WATCH HAS BEEN ISSUED FOR THE EAST COAST OF THE UNITED
STATES FROM NORTH OF SURF CITY TO DUCK NORTH CAROLINA...INCLUDING
THE PAMLICO AND ALBEMARLE SOUNDS.

A TROPICAL STORM WATCH HAS BEEN ISSUED FROM CAPE FEAR NORTH CAROLINA
NORTHEASTWARD TO SURF CITY.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WATCH IS IN EFFECT FOR...
* NORTH OF SURF CITY TO DUCK NORTH CAROLINA...INCLUDING THE PAMLICO
AND ALBEMARLE SOUNDS

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* TURKS AND CAICOS ISLANDS

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* SOUTHEASTERN BAHAMAS
* CAPE FEAR TO SURF CITY

INTERESTS FROM VIRGINIA NORTHWARD TO NEW ENGLAND SHOULD MONITOR
THE PROGRESS OF EARL.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE
THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL
METEOROLOGICAL SERVICE.
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OBX definitely in the TS wind field in this forecast....
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Quoting StormW:
Here's a good site for folks:

Experimental TROPICAL CYCLONE IMPACTS - DECISION SUPPORT
Good post Storm, hope people use it to their advantage.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.