Category 2 Irene Approaches The Bahamas

By: Dr. Jeff Masters , 7:51 AM GMT on August 23, 2011

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As of 2am EDT, Hurricane Irene was located at 20.1N, 69.7W, 135 miles southeast of Grand Turk Island. It was moving west-northwest at 12 mph with maximum sustained winds of 100 mph, making it a Category 2 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 978 mb. Hurricane warnings have been issued for the northern coast of the Dominican Republic from the Haiti board to Cabo Engano, the southeastern and central Bahamas, and the Turks and Caicos islands. Hurricane watches have been posted for the north coast of Haiti from Le Mole, St. Nicholas to the Dominican border and the northwestern Bahamas. Tropical storm warnings are in effect for all of Haiti and the southern coast of the Dominican Republic from Cabo Engano to Santo Domingo.

5AM Update
As of 5am EDT, Hurricane Irene was located at 20.3N, 70.1W, 105 miles southeast of Grand Turk Island. It was moving west-northwest at 12 mph with maximum sustained winds of 100 mph, keeping it a Category 2 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 978 mb.

Figure 1 shows that Irene is maturing into a vigorous storm, with apparent waves in the western edge of the cirrus outflow.


Figure 1 IR satellite view of Irene taken at 135AM EDT, August 22, 2011

Track Forecast

Irene is forecast to move to the north-northwest, passing over all of the Bahama islands by Thursday evening, at which points it starts curving to the north. Irene is forecast to make landfall in the US near Wilmington, NC Saturday evening. However, it is important to note that this is not a definitive forecast, the average forecast error for day 5 is 250 miles. The timing of Irene's recurvature depends on how quickly several small troughs of low pressure in the Northeastern US move to the east. After Saturday, Irene may pose a threat to the mid-Atlantic coastline and locations further north, but it is too early to make a skillful forecast for those regions.

NHC is forecasting for Irene to become a major hurricane (winds faster than 110 mph), within 24 hours, then reaching peak intensity at 130 mph (Category 4 storm) by 8pm EDT Thursday evening.

Forecast models and adaptive observations
The different forecast models are in rough agreement until Irene nears the Carolinas. The dynamical hurricane forecasting models, GFDL and HWRF, have Irene making landfall near Charleston, SC. NGFDL (a variant of the GFDL that uses NOGAPS for background conditions) has landfall near Morehead City, NC, and the GFS has Irene crossing the Outer Banks. The UKMET forecast track splits the difference, placing Irene near Myrtle Beach, SC at landfall.

To reduce the model spread, and improve the track forecast error, the NOAA Gulfstream IV and an Air Force WC-130J have been flying dropsonde missions north of Irene. A dropsonde is an meteorological instrument package dropped from a plane that can tell you the vertical profile of temperature, pressure, moisture, and winds. By flying these missions, the dropsondes can improve all of the numerical weather prediction models initial picture of the atmospheres, which improves the forecast. Also, NHC has asked NWS offices in the southeastern US that launch weather balloons to do so every 6 hours instead of the normal 12 hour frequency.


Figure 2 Official track forecast of Irene as of 2am.

5AM update
The 00Z ECMWF forecast is available and Figure 3 shows the maximum wind speed over the next week for the eastern coast of the US. Green indicates tropical storm force winds, while yellow and orange are hurricane-force winds. The important thing is not to fixate on the predicted landfall location, but to see that Irene's winds will affect areas far away from landfall. The GFS, not shown, agrees with ECMWF that Irene will have a large area of tropical-storm force winds associated with it.

Figure 3 Maximum wind-speed in mph from the 00Z August 23 ECMWF forecast for the next week.

Impacts

In the immediate future, Irene is expected to have a significant impact on the Bahamas and surrounding islands. Hurricane force winds are forecast to reach the southeastern Bahamas and the Turks and Caicos sometime this afternoon or evening. These locations can also expect 5-10 inches of rain. Three to six inches of rain are forecast over northern Hispaniola, with isolated areas receiving up to 10 inches. This could lead to flash flooding and mudslides in mountaineous terrain. NHC is predicting a storm surge of 9-13 feet above normal tide level for the southeastern Bahamas and the Turks and Caicos.

Outside of the islands immediately impacted by Irene, it is my judgement that everybody living on the eastern coast of the US should monitor Irene and review their hurricane preparations over the next few days.

Dr. Masters will have a new blog entry this morning, and Angela Fritz will be covering the afternoon. I'll be back on third shift tonight.

Thanks for reading,

Dr. Rob Carver

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Thankfully, Tampa Bay and almost all Florida are out of the woods this morning. I hope Irene make that turn well before and recurve before touching any US land area. My thoughts and my pray are with those in Hispaniola and Bahamas.
Member Since: August 23, 2006 Posts: 0 Comments: 1569
Quoting killdevilmax:
OBXNags Head,
I think a real strong chance of evac. I think the track MAY shift a little more east and we may get grazed but still will be slammed.


Thanks for the response...
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Quoting K8eCane:
If it were just me I wouldnt stress it so much, but i have to think about my son. We have financial limitations too. Our family is 40 miles south which wouldnt help. They are right on the coast too. And anywhere I go I wouuld have to drive back (even if I could afford to go) and I would probly get us killed trying to dodge all the obstacles. I learned THAT in Floyd. Ita a freakin no win situation. I WAS NOT expecting a freakin cat 4 or 5 or even high end 3.


You don't have to drive hundreds of miles. Find a friend in town who is at a higher elevation. It's better than nothing. As long as you avoid the storm surge.
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Quoting Grandpato4:
The new track does is not favorable for Atlantic Beach. I am certainly leaving on Wednesday to head to Raleigh.


Sir, if you are anywhere near the GA-SC border all the way to NC i believe that if you can afford leaving it would be a wise move. The biggest asset is life and one can't be too cautious when preserving it. BTW why don't y'all over there in the Carolinas come here to Biloxi Mississippi it is safe here and we got awesome Casinos for your entertainment.
Member Since: August 1, 2007 Posts: 0 Comments: 165
That 1893 storm sounds scarey especially that it wiped and Hog island off the map.

It's Wikipedia so think of it as entertainment but:

"New York City's leading hurricane historian, Nicholas Coch, a professor of coastal geology at Queens College, believes that this has been the only reported incidence of the removal of an entire island by a hurricane.[3]"
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530. 900MB
The "Long Island Express" of 1938.
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Thank's God. Power was reestablished in my area this morning and the ATL look loke this....



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Being in east central florida, I wont let my guard down until I see definite NW turn of storm and it passes my latitude. With that in mind, paranoia requires me to ask you to look at a feature to the NE of Irene. Can that make a change to what I hope is a recurve of Irene out to sea? BTW, the trough digging down pleases me because it looks like it will force Irene to miss everyone from a direct hit.
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Quoting hurricane23:


The threat for tropical storm winds across mainland south florida has continued to decrease. Gusty winds in the range of 25-35mph and some rain is expected as the storm makes its closest approach . The strongest winds will be over offshore waters.



Morning Adrian.

Shields intact this morning, hopefully they hold, we don't need a CAT4 around here, nobody does...
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If it were just me I wouldnt stress it so much, but i have to think about my son. We have financial limitations too. Our family is 40 miles south which wouldnt help. They are right on the coast too. And anywhere I go I wouuld have to drive back (even if I could afford to go) and I would probly get us killed trying to dodge all the obstacles. I learned THAT in Floyd. Ita a freakin no win situation. I WAS NOT expecting a freakin cat 4 or 5 or even high end 3.
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Quoting Bobbyweather:

By any chance do you know when the recon reaches Irene?

Yes



Just going feet wet off PR
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting AllStar17:


Very shortly.

Thanks. I saw the NHC site, and the first flight was scheduled for 12z, but I couldn't find recon readings.
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Well, I know what the slow down was once again:

The AB high has retreated slightly to the East, probably from the energy from the shortwave entering the picture, leaving her in fairly weak steering currents..



EDIT: Also of note, the Texas high continues to retreat into the GOM
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Tomorrow a Catagory 4 over New Providence
Monday a catigory 2 over Proivdence, RI.
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521. 900MB
Quoting HCW:



Here you go . Now on with the countdown



Thanks so much. Scary!
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Quoting Bobbyweather:

By any chance do you know when the recon reaches Irene?


Very shortly.
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Quoting CaneHunter031472:
I completely concur with the NHC and the models. As far as calling this a fish storm well it already hit the US yesterday so no it is not, and I am confident that a second landfall is very possible over North Carolina due to the shift in the models. The ridge weakens enough to allow Irene to take the more to the north path due to this secong trof. after that is all done and over we should have a basically stalled system in the Atlantic with 98L and a much stronger ridge stopping it from moving north. I give North Carolina a 75% chance of direct impact.


I'm pretty sure the second and third landfalls will come over the Turks, Caicos and Bahama Islands. Long before this storm gets to North Carolina it could have already done a lot of damage to those Islands it's about to steam roll. I pray everyone there is preparing for the worse.
Member Since: August 25, 2006 Posts: 1 Comments: 3010
Quoting Orcasystems:


No

By any chance do you know when the recon reaches Irene?
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wow....looks like maybe only the bahamas get this one and they are little islands with no place to go!! The models seem to be shifting out to sea after the bahamas.... I'm praying for those that are in the bahamas!!!
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Quoting BDAwx:
Ok now I'm confused, what do we all mean by "direct impacts" from hurricane Irene?

I would say Florida is out of the woods for a landfall from Irene but it could still see direct impacts. Direct impacts being wind, rain, and surf generated by the storm. Just a reminder that the storm is huge and is likely going to get bigger as it pulls more northward (away from any inhibiting factors of hispaniola's mountains, and natural increase in size from latitudinal gain) so the storm needn't make landfall on you to give you hurricane winds.


The threat for tropical storm winds across mainland south florida has continued to decrease. Gusty winds in the range of 25-35mph and some rain is expected as the storm makes its closest approach . The strongest winds will be over offshore waters.
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Quoting ElConando:
I like the early morning blog, calm and fairly civil and not going 3,000 mph.



I bet most of them were up all night, or most of it anyway. I'd say we have till 10 or 11 and the madness will begin again.
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Quoting Bobbyweather:
Is recon in Irene yet?


No
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Is recon in Irene yet?
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Definitely going to be a tough forecast...

Looking at the larger scale pattern in the water vapor loop you can see the stagnant ridge over Texas unwilling to break down, with a short wave riding over the top of this, while the large scale trough over the Northeast is ejecting but leaving a weakness in the subtropical ridge along the coast (our future path).

The ridge north of Irene will strengthen a bit through the day today, so I'm forecasting a slight left shift in motion to 280 or 285 heading and a slight increase of speed to 12-14 mph this evening.

Longer term it depends on how these shortwaves interact with the residual weakeness in the east. If the Texas ridge rebounds north, then the shortwaves will dive further south over the east. Less rebound and the shortwaves will move more zonally leading to a more western solution.


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511. GoWVU
As of now how much wind and rain should/will the Charleston area feel with Irene?
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OBXNags Head,
I think a real strong chance of evac. I think the track MAY shift a little more east and we may get grazed but still will be slammed.
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Quoting obxnagshead:
OK so chances of OBX Nags Head getting evacuated???? Wondering if I really need to start making plans this early, but I guess its never to early to plan!
How much time do you need to bug out by Saturday? yeah, definitely time to seriously start making plans.
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To shift gears off of Irene for a minute, I read something on here a few days ago on something monsoonal in nature for Texas. Has anyone heard or read anymore news on this. I am afraid the Texas drought will extend until next summer if we fail to get something tropical in here within the next few weeks. Tropical activity usually wains after mid to late September for us.
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Quoting lennykat4:



Thank you SOOOO much. This is exactly the kind information I'm hoping to find on here.
What is the likeliness that those two highs could bridge together? As long as that ridge exists, I still see it as a possible obstical for it. This is gonna be close.
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8:00am Advisory
Click image to enlarge.

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Complete Update

HH Mission #8 is enroute and some models are calling for a CAT 5 to Charleston.

TS BUSTED FORECAST ALIBI





Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting TropicalXprt:
You know, it use to be that the NHC made actual weather predictions. Clearly they are so consumed in their models now. I think they are wrong on this track, and have it way to far east. Mark my words this storm will be south of there projected target later today.


Being a NC resident, i HOPE your wrong dude:)
Member Since: August 4, 2011 Posts: 46 Comments: 4481
I like the early morning blog, calm and fairly civil and not going 3,000 mph.
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Quoting uptxcoast:
I know that everyone is focused on Irene right now and rightly so but here is some grim news from Texas.

Good Luck and God Bless to everyone in Irene's path.

Link

As historically bad as this summer's drought has been, we may not have seen the worst of it.

There's growing concern among some scientists that Texas' drought could linger through another dry winter and return next summer to more deeply ravage an already water-stressed state.

"I've started telling anyone who's interested that it's likely much of Texas will still be in severe drought this time next summer, with water supply implications even worse than those we are now experiencing," said John Nielsen-Gammon, the state climatologist and a Texas A&M University professor.

In the short term, there's little relief in store. Houston topped 100 degrees (101) again Monday, beating the record of 32 total days with temperatures reaching the century mark set in 1980 (not consecutive).


I would recommend reading the entire article as it really summarizes how bad it really is down here.


I am about to become a SERIOUS WISHCASTER.

This drought and heat wave are making people crazy! There are no green lawns, tree's are dying and it just continues........


We sold all of our calves Friday at auction. With prices so low, we might as well have given them away, but when you have no grass and can't get any hay, you can't keep what you can't feed. Sad...We live in fear everyday of grass fires.
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Quoting obxnagshead:
OK so chances of OBX Nags Head getting evacuated???? Wondering if I really need to start making plans this early, but I guess its never to early to plan!


Well you would be on the NE quadrant, so you can probably expect some strong weather either way, but I would be making early preps, and that way if an evac is ordered you have everything done except for leaving. If nothing else it's a dry run..
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OK so chances of OBX Nags Head getting evacuated???? Wondering if I really need to start making plans this early, but I guess its never to early to plan!
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Quoting Smikey:
I don’t normally jump into the foray of post slinging during wunderhype time, (with no disrespect to those that actually bring meaningful facts to the discussion) but something that has not been discussed:

The GFS, and Euro and other models continue as of this morning to under forecast the strength of the Upper level disturbances over the Northeast US. Its fall in the Northeast this morning (55 degrees where I’m near the NJ coast)


I agree with met Steven DiMartino with his post this morning stating:


“However, the models have been under forecasting the strength of these disturbances as early as this morning’s observations, and that factor can not be discounted when examining the model guidance. A strong disturbance means that influential steering currents from the southwest must be taken into account in the error and thus a faster turning of Irene back into the Atlantic is still very much on the tables. In fact, there are now several models pointing to Irene staying off the East coast completely.”




I wish we could be sure of that. But until I hear it from the NHC....
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Quoting Skyepony:
Good morning everyone.. Nice cone shift. My biggest concern about it..the models (gfs for example) have 98L fly across the Atlantic helping to weaken & erode the high. 98L decoupled overnight & is a naked swirl.


Good Morning and yes Sky... if it wasn't for P18L then the High would have some additional strength to push back, if it deteriorates too much then it could be troublesome.
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Quoting Neapolitan:
ATCF 1200z update:

AL, 09, 2011082306, , BEST, 0, 201N, 697W, 85, 978, HU, 64, NEQ, 45, 30, 20, 35, 1010, 300, 15, 0, 0, L, 0, , 0, 0, IRENE, D,


On satellite right now looks like 20,8N 70,5W if that blow up is over center.

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ATCF's complete 90L file:

BEGIN
NHC_ATCF
invest_al902011.invest
FSTDA
R
U
040
010
0000
201108231232
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 90, 2011, DB, O, 2011082306, 9999999999, , , , , , METWATCH, , AL902011
AL, 90, 2011082206, , BEST, 0, 126N, 149W, 25, 1008, DB, 0, , 0, 0, 0, 0,
AL, 90, 2011082218, , BEST, 0, 123N, 168W, 25, 1008, DB, 0, , 0, 0, 0, 0,
AL, 90, 2011082300, , BEST, 0, 124N, 180W, 25, 1008, DB, 0, , 0, 0, 0, 0,
AL, 90, 2011082306, , BEST, 0, 124N, 190W, 25, 1008, DB, 0, , 0, 0, 0, 0, 1010, 150, 90, 0, 0, L, 0, , 0, 0, INVEST, S,
AL, 90, 2011082312, , BEST, 0, 125N, 200W, 25, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1011, 180, 90, 0, 0, L, 0, , 0, 0, INVEST, S,

Expect models shortly...
Member Since: Posts: Comments:
I completely concur with the NHC and the models. As far as calling this a fish storm well it already hit the US yesterday so no it is not, and I am confident that a second landfall is very possible over North Carolina due to the shift in the models. The ridge weakens enough to allow Irene to take the more to the north path due to this secong trof. after that is all done and over we should have a basically stalled system in the Atlantic with 98L and a much stronger ridge stopping it from moving north. I give North Carolina a 75% chance of direct impact.
Member Since: August 1, 2007 Posts: 0 Comments: 165
Quoting uptxcoast:
I know that everyone is focused on Irene right now and rightly so but here is some grim news from Texas.

Good Luck and God Bless to everyone in Irene's path.

Link

As historically bad as this summer's drought has been, we may not have seen the worst of it.

There's growing concern among some scientists that Texas' drought could linger through another dry winter and return next summer to more deeply ravage an already water-stressed state.

"I've started telling anyone who's interested that it's likely much of Texas will still be in severe drought this time next summer, with water supply implications even worse than those we are now experiencing," said John Nielsen-Gammon, the state climatologist and a Texas A&M University professor.

In the short term, there's little relief in store. Houston topped 100 degrees (101) again Monday, beating the record of 32 total days with temperatures reaching the century mark set in 1980 (not consecutive).


I would recommend reading the entire article as it really summarizes how bad it really is down here.


I am about to become a SERIOUS WISHCASTER.

This drought and heat wave are making people crazy! There are no green lawns, tree's are dying and it just continues...

'Tis a frightening prospect. Don't know whether you caught this Drought Information Statement from NWS last week:

ALL OF NORTH TEXAS IS NOW IN AT LEAST SEVERE DROUGHT (D2)...WITH THE
VAST MAJORITY OF THE REGION IN EXTREME OR EXCEPTIONAL DROUGHT. WATER
RESOURCES HAVE DECREASED DRAMATICALLY THIS SUMMER...AND CROP LOSSES
WILL LIKELY SET RECORD DOLLAR AMOUNTS.

THE HEAT IS EXPECTED TO CONTINUE THE REMAINDER OF THE SUMMER...WITH
THE DROUGHT CONTINUING UNABATED WELL INTO THE UPCOMING AUTUMN. WITH
THE POTENTIAL FOR ANOTHER DRY LA NINA WINTER...THERE IS LITTLE TO
SUGGEST ANY END TO THE DROUGHT.
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Quoting Rainman32:
That does often seem to be the case, here it is illustrated.


There is a javascript version of all the graphics archives available online here: IRENE Graphics Archive
Here is the latest animated Doom Cone






That is the most enlightening post we'll see all day!!!
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I don’t normally jump into the foray of post slinging during wunderhype time, (with no disrespect to those that actually bring meaningful facts to the discussion) but something that has not been discussed:

The GFS, and Euro and other models continue as of this morning to under forecast the strength of the Upper level disturbances over the Northeast US. Its fall in the Northeast this morning (55 degrees where I’m near the NJ coast)


I agree with met Steven DiMartino with his post this morning stating:


“However, the models have been under forecasting the strength of these disturbances as early as this morning’s observations, and that factor can not be discounted when examining the model guidance. A strong disturbance means that influential steering currents from the southwest must be taken into account in the error and thus a faster turning of Irene back into the Atlantic is still very much on the tables. In fact, there are now several models pointing to Irene staying off the East coast completely.”

Member Since: June 5, 2008 Posts: 0 Comments: 51
Quoting oakland:


That's what I'm afraid of.
...and she's been around the block a couple of times already and she's got a full tank of gas! CAT4 here she comes!
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There's a big difference in accuracy between 7 days out and where we are now: 4 days out and so the track becomes much more likely.
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Quoting BDAwx:
Ok now I'm confused, what do we all mean by "direct impacts" from hurricane Irene?

I would say Florida is out of the woods for a landfall from Irene but it could still see direct impacts. Direct impacts being wind, rain, and surf generated by the storm. Just a reminder that the storm is huge and is likely going to get bigger as it pulls more northward (away from any inhibiting factors of hispaniola's mountains, and natural increase in size from latitudinal gain) so the storm needn't make landfall on you to give you hurricane winds.


Many see "direct impact" as being the center making landfall somewhere. However, yes you're right, the entire east coast from FL to NC at least will see an impact from Irene in the way of either wind, rain, beach erosion or a combination thereof.
Member Since: September 4, 2005 Posts: 41 Comments: 7526
485. Skyepony (Mod)
Good morning everyone.. Nice cone shift. My biggest concern about it..the models (gfs for example) have 98L fly across the Atlantic helping to weaken & erode the high. 98L decoupled overnight & is a naked swirl.
Member Since: August 10, 2005 Posts: 161 Comments: 37158

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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.

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