Category 4 Earl headed for a close brush with North Carolina

By: Dr. Jeff Masters , 31. elokuuta 2010 klo 15:16 (GMT)

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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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1632. mojofearless
1. syyskuuta 2010 klo 01:17 (GMT)
Pay close attention, and don't let her wait until the last minute. Remember the Bolivar Peninsula.
Member Since: 13.08.2009 Posts: 0 Comments: 172
1628. TruthCommish
31. elokuuta 2010 klo 22:39 (GMT)
Quoting gulfbreeze:
No it's not !

Ok, so the movement the last few hours is NOT more northerly than the last two days?
Member Since: 4.09.2009 Posts: 0 Comments: 158
1627. TruthCommish
31. elokuuta 2010 klo 22:21 (GMT)
Quoting angiest:


You didn't get your BA in Underwater Basket Weaving?


(CRICKETS)
Member Since: 4.09.2009 Posts: 0 Comments: 158
1626. songman77
31. elokuuta 2010 klo 22:08 (GMT)
Is it 2 hours 'til they update forecast tracks?
Member Since: 11.08.2009 Posts: 0 Comments: 25
1625. wdtcnewsonlinewx
31. elokuuta 2010 klo 22:07 (GMT)
Member Since: 1.06.2010 Posts: 0 Comments: 82
1623. bwat
31. elokuuta 2010 klo 21:57 (GMT)
I don't know what to think! I like the current track keeping him just east of us here in eastern NC, but I have been keeping up with Earl since genesis. I have noticed a more westerly track with every other advisory. I don't want to see it, but just from the history of Earl, a Morehead City to Hatteras landfall doesnt seem so unlikley. I was lurking at work with my dial up connection and was reading of a northern movement which thrilled me. I got home and run the visible loop, and the northern component seemed short lived. Back to lurking for me. Any thoughts would be appreciated.
Member Since: 18.08.2009 Posts: 0 Comments: 338
1622. gulfbreeze
31. elokuuta 2010 klo 21:57 (GMT)
Quoting aislinnpaps:
Good afternoon everyone. It looks like Earl is finally beginning his slow turn north.
No it's not !
Member Since: 13.06.2010 Posts: 0 Comments: 828
1621. SQUAWK
31. elokuuta 2010 klo 21:53 (GMT)
Quoting TexasGulf:


Yes, SouthEast Texas had our annual Burrito Festival last weekend. It should have made it into the upper levels of the atmosphere by now.
;>)


That is the best I have seen all day. Can't believe that DJ didn't jump all over that. LMAO!!!
Member Since: 9.12.2008 Posts: 0 Comments: 2498
1620. Floodman
31. elokuuta 2010 klo 21:51 (GMT)
Quoting TexasGulf:


Well, the official forecast track is based on the current models. All of the models are from 2:00pm EST. The NHC can't make a real adjustment to Earl's forecast track until the new model data is available.

Watch for the NHC's official report at 8:00pm. It should have the new data for an updated track.


AND the current modeling data is deruived from observational data from the period prior to the run; most of the "current" model data is in reality, some 6 hours old or more
Member Since: 2.08.2006 Posts: 10 Comments: 9922
1618. Halyn
31. elokuuta 2010 klo 21:48 (GMT)
Quoting JRnOldsmar:


Link


Thank you .. :)
Member Since: 7.08.2008 Posts: 0 Comments: 98
1617. NWWNCAVL
31. elokuuta 2010 klo 21:48 (GMT)
I find it somewhat odd that as soon as Warnings go up for NC a lot of peole seem to be jumping on it moving east now...Are ya'll just anti-NHC or what? As teh floodman points out it is moving wnw...I am here as an observer only, no knowlege of weather...But, it just seems like a lot of bologna...

NO more off topic, and if you have an explanation for now a bermuda hit, please say what it is...
Member Since: 20.08.2007 Posts: 0 Comments: 391
1616. funeeeg
31. elokuuta 2010 klo 21:47 (GMT)
1550; yes I think it is. on the last reckon the max flt level winds of 128kts were at least 30 nautical miles from the lowest pressure readings which indicate a new eyewall. You can see the outline of the new eye on the shortwave IR link
Member Since: 20.10.2005 Posts: 0 Comments: 218
1615. stormpetrol
31. elokuuta 2010 klo 21:47 (GMT)
Quoting washingtonian115:
Looks like Fiona is coming twards her death..But we can't write her off just yet.

Fiona has been holding her own despite that monster she is so close to, will really be interesting to see how this plays out , cant recall seeing 2 storms that close in the Atlantic basin before.
Member Since: 29.04.2007 Posts: 0 Comments: 7506
1614. RuBRNded
31. elokuuta 2010 klo 21:46 (GMT)
Quoting DestinJeff:


No, but they do all have very nice teeth.

You mean tooth?
Member Since: 29.07.2009 Posts: 0 Comments: 319
1613. aislinnpaps
31. elokuuta 2010 klo 21:46 (GMT)
Good afternoon everyone. It looks like Earl is finally beginning his slow turn north.
Member Since: 22.08.2009 Posts: 0 Comments: 3112
1612. aasmith26
31. elokuuta 2010 klo 21:46 (GMT)
new blog up yall
Member Since: 30.06.2006 Posts: 5 Comments: 226
1611. MiamiHurricanes09
31. elokuuta 2010 klo 21:46 (GMT)
NEW BLOG
Member Since: 2.09.2009 Posts: 130 Comments: 21032
1610. CaicosRetiredSailor
31. elokuuta 2010 klo 21:46 (GMT)




Good afternoon from pleasant sunny Providenciales in the Turks and Caicos Islands.

CRS
Member Since: 12.07.2007 Posts: 0 Comments: 5984
1609. TexasGulf
31. elokuuta 2010 klo 21:45 (GMT)
Quoting oceanblues32:
but the 5 pm came out and there was no adjustment


Well, the official forecast track is based on the current models. All of the models are from 2:00pm EST. The NHC can't make a real adjustment to Earl's forecast track until the new model data is available.

Watch for the NHC's official report at 8:00pm. It should have the new data for an updated track.
Member Since: 28.04.2008 Posts: 0 Comments: 354
1607. MiamiHurricanes09
31. elokuuta 2010 klo 21:45 (GMT)
Blog Update

Earl a threat to the eastern seaboard; Fiona could dissipate soon; 98L worth tracking
Member Since: 2.09.2009 Posts: 130 Comments: 21032
1606. almartia
31. elokuuta 2010 klo 21:45 (GMT)
Quoting stormpetrol:
Any opinions on Fiona? I doubt she will turn NW as fast as predicted, jmo, oh and yes I'm a westcaster :)


petrolero
Member Since: 18.08.2008 Posts: 0 Comments: 6
1604. KEEPEROFTHEGATE (Mod)
31. elokuuta 2010 klo 21:44 (GMT)
Quoting washingtonian115:
I'm qouting this from a artical.."their is little know about hurricanes,and tropical weather.Further sudies need to be intended,and not much is known about these storms"


The formation of tropical cyclones is the topic of extensive ongoing research and is still not fully understood. While six factors appear to be generally necessary, tropical cyclones may occasionally form without meeting all of the following conditions. In most situations, water temperatures of at least 26.5 °C (79.7 °F) are needed down to a depth of at least 50 metres (160 ft); waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms. Another factor is rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone.High humidity is needed, especially in the lower-to-mid troposphere; when there is a great deal of moisture in the atmosphere, conditions are more favorable for disturbances to develop. Low amounts of wind shear are needed, as high shear is disruptive to the storm's circulation. Tropical cyclones generally need to form more than 555 kilometres (345 mi) or 5 degrees of latitude away from the equator, allowing the Coriolis effect to deflect winds blowing towards the low pressure center and creating a circulation. Lastly, a formative tropical cyclone needs a pre-existing system of disturbed weather, although without a circulation no cyclonic development will take place.

Member Since: 15.07.2006 Posts: 163 Comments: 52230
1603. Floodman
31. elokuuta 2010 klo 21:43 (GMT)
At 13:45 UTC, Earl was at 67.5W 21.5N and at the last image, at 20:45 UTC, he's at 68.9W 22.1Nso in 7 hours he's moved 1.4 west and .6 n...he's moving approximately WNW; no aspect change as yet
Member Since: 2.08.2006 Posts: 10 Comments: 9922
1602. RickWPB
31. elokuuta 2010 klo 21:43 (GMT)
Quoting naitsabes:
yeah, but those guys do not know what they are talking about, the models are all wrong too; in addition, this storm is comming to Florida, I feel it, that is what you'll hear from many on the blog


Poof!
Member Since: 26.09.2007 Posts: 0 Comments: 340
1600. washingtonian115
31. elokuuta 2010 klo 21:42 (GMT)
Looks like Fiona is coming twards her death..But we can't write her off just yet.
Member Since: 14.08.2010 Posts: 10 Comments: 15707
1597. funeeeg
31. elokuuta 2010 klo 21:41 (GMT)
1548. actually "becoming more symmetric"! (Edit) double m
Member Since: 20.10.2005 Posts: 0 Comments: 218
1596. WandoMarsh
31. elokuuta 2010 klo 21:40 (GMT)
Quoting CosmicEvents:
I don't believe that they have...but I'm almost certain that they've never been hit by any hurricane moving NE, which I suppose is still a possibility depending on the exact timing. Let's hope it doesn't happen.


Ophelia was moving NE as it raked the coast of NC in 2005.
Member Since: 1.09.2008 Posts: 0 Comments: 19
1595. stormpetrol
31. elokuuta 2010 klo 21:40 (GMT)
Any opinions on Fiona? I doubt she will turn NW as fast as predicted, jmo, oh and yes I'm a westcaster :)
Member Since: 29.04.2007 Posts: 0 Comments: 7506
1594. marmark
31. elokuuta 2010 klo 21:39 (GMT)
Quoting sammywammybamy:
Fiona Crashing into Earl...

It almost looks like biology class LOL
Member Since: 1.02.2004 Posts: 2 Comments: 243
1593. oceanblues32
31. elokuuta 2010 klo 21:39 (GMT)
but the 5 pm came out and there was no adjustment
Member Since: 8.11.2009 Posts: 0 Comments: 207
1590. KEEPEROFTHEGATE (Mod)
31. elokuuta 2010 klo 21:39 (GMT)
Member Since: 15.07.2006 Posts: 163 Comments: 52230
1589. marmark
31. elokuuta 2010 klo 21:38 (GMT)
Quoting TexasGulf:


Yes, SouthEast Texas had our annual Burrito Festival last weekend. It should have made it into the upper levels of the atmosphere by now.
;>)
Too funny. I laughed out loud!
Member Since: 1.02.2004 Posts: 2 Comments: 243
1588. washingtonian115
31. elokuuta 2010 klo 21:38 (GMT)
So right now Earl is making that turn which means best cast senario?
Member Since: 14.08.2010 Posts: 10 Comments: 15707
1587. washingtonian115
31. elokuuta 2010 klo 21:38 (GMT)
So right now Earl is making that turn which means best cast senario?
Member Since: 14.08.2010 Posts: 10 Comments: 15707
1583. Floodman
31. elokuuta 2010 klo 21:37 (GMT)
Quoting washingtonian115:
I'm qouting this from a artical.."their is little know about hurricanes,and tropical weather.Further sudies need to be intended,and not much is known about these storms"


Oh, we have vast information about tropical cyclones; the problem is that we have a great deal more to learn
Member Since: 2.08.2006 Posts: 10 Comments: 9922

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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