ATL: Ex-Tropical Storm FIONA - Discussion

[BigB0882]

I am very confused about the 1 in 100 comment as well. The way it reads is that a storm hits the US from the southeast only once every 100 years. Clearly not true. So then, what did he mean?

[Cyclone1]

I think what he was saying was that a storm hits the Mid-Atlantic from a diagonal southeast path, like Isabel, only perhaps further north.

[ROCK]

future Fiona looks like a great deal south and I would not discount the long range CMC run...hard to tell beyond 6 days how the pattern will change but its going to. All this talk about "recurve" is premature.... and to be honest every time I hear it (which is every other post) makes want to puke....

[Steve H.]

Yes I agree. 97L is way displaced right now to be affected by the previous storms. We will have to see how it evolves, whether it be a Caribbean cruiser or an east coast threat.

[perk]

future Fiona looks like a great deal south and I would not discount the long range CMC run...hard to tell beyond 6 days how the pattern will change but its going to. All this talk about "recurve" is premature.... and to be honest every time I hear it (which is every other post) makes want to puke....

I agree Rock, but what i don't get is why all of a sudden the GFS which has been bad mouthed on this board for years suddenly the model of choice and the Euro is the outlier, at least to some.

[perk]

Great posts Chris and Frank. The natives on the 97 model thread are getting excited. Nice to see there might be little reason for the excitement.

You might want to take a look at the last couple of runs of the euro.

I've seen the last two runs of the euro and both show a system a couple of hundred miles at least off the US East Coast. Taking into account wxman57's observation that the Euro has been too far west with most systems this year why should anyone be concerned yet...not saying it won't happen but 10 days out a lot can happen.

The point being the westward trend, and that can't be ignored.

[wxman57]

... but what i don't get is why all of a sudden the GFS which has been bad mouthed on this board for years suddenly the model of choice and the Euro is the outlier, at least to some.

The GFS had a major physics revision/upgrade back in June. It's still not clear what if it has any particular bias or not with respect to predicting TC tracks. So it's sort of an unknown at this point. The Euro has tended to be too far west on the previous 5 systems, keeping too strong a ridge to the north of each system.

Is the Euro doing it again? Don't know that. Canadian is sort of in agreement with the Euro, and the Canadian was the best performer beyond 72 hours the last 2 years. I don't trust the new GFS yet, particularly the way it keeps trying to merge Danielle/Earl and now Earl/Fiona.

[ncweatherwizard]

And the updated GFS didn't go live until late July even. Hard to say if there will be any major affect on TC track. My understanding was that the biggest concern was to reduce the occurrence of precipitation "bombs" and to yield a more realistic precipitation field for mid-latitude systems.

[WeatherGuesser]

I don't get that either...

Hazel, Hugo, David are three in about 60 years.

How strong were they? Maybe he's thinking this will be stronger. We've had quite a few '100 year' floods and other storms in the last few years.

[StormClouds63]

Just an opinion and not an official forecast.

97L might be a threat to the Bahamas and eventually the SE U.S. coastline ... Isabel or Floyd track is not of the question. Still possible that this follows the recurve script and pushes out into the Atlantic. Much less likely is a westward track into the Caribbean. I don't think the ridge would hold. Florida northward to the Carolinas will be watching next week. After Danielle and Earl depart, future Fiona will take center stage in the tropics. She'll have her 15 minutes of fame, perhaps more. The signature storm of 2010 has yet to emerge. Maybe the obvious choice will be the one (Igor)!

GOM and Caribbean remain quiet for the time being.

[cycloneye]

Remains at 80%.

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT SAT AUG 28 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON MAJOR
HURRICANE DANIELLE...LOCATED ABOUT 345 MILES SOUTHEAST OF BERMUDA
...AND ON TROPICAL STORM EARL...LOCATED ABOUT 965 MILES EAST OF THE
NORTHERN LEEWARD ISLANDS.

A BROAD LOW PRESSURE SYSTEM...ASSOCIATED WITH A VIGOROUS TROPICAL
WAVE...IS LOCATED ABOUT 175 MILES SOUTHWEST OF THE SOUTHERNMOST CAPE
VERDE ISLANDS. THIS SYSTEM CONTINUES TO SHOW SIGNS OF ORGANIZATION
...AND ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR A TROPICAL
DEPRESSION TO FORM DURING THE NEXT COUPLE OF DAYS. THERE IS A HIGH
CHANCE...80 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT 15 TO 20 MPH.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BRENNAN

[ColinDelia]

Vorticity




Dvorak examples


Most recent Dvorak Classification (0600 UTC)
28/0600 UTC 12.7N 27.2W T1.5/1.5 97L

[ColinDelia]

Satellite winds compilation. Some westerlies. Must be close.
http://rammb.cira.colostate.edu/product ... 1008280600

[Blown Away]

The 72 hour TAFB is much farther south and seems to indicate a close run into the NE Caribbean.

[KWT]

Its got a decent enough structure but seems to be lacking a little in terms of convection so probably only slow strengtheningm, still a decent convective burst will probably be enough to upgrade this one...

[WeatherGuesser]

Still unchanged at 80%


1. A BROAD LOW PRESSURE SYSTEM...ASSOCIATED WITH A VIGOROUS TROPICAL
WAVE...IS LOCATED ABOUT 250 MILES SOUTHWEST OF THE SOUTHERNMOST CAPE
VERDE ISLANDS. ALTHOUGH THIS SYSTEM HAS CHANGED LITTLE IN
ORGANIZATION DURING THE LAST SEVERAL HOURS...ENVIRONMENTAL
CONDITIONS REMAIN FAVORABLE FOR A TROPICAL DEPRESSION TO FORM
DURING THE NEXT COUPLE OF DAYS. THERE IS A HIGH CHANCE...80
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WESTWARD AT 15 TO 20 MPH.


Isn't 15-20 MPH kinda quick?

[HURAKAN]

not looking too hot atm, but should develop down the road

[cycloneye]

12z Best Track

AL, 97, 2010082812, , BEST, 0, 134N, 284W, 25, 1008, LO

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 010.invest

[BigA]

not looking too hot atm, but should develop down the road

Agreed. They can't all hit the water and immediately go gangbusters. It's taking it's time, but shear is low, SAL is to the north (though it could inhibit some) and waters are steaming. It should develop. There's too much model consensus for it not to; I think every model that I can remember (CMC, NOGAPS, GFS,GFDL,HWRF,WRF,ECMWF,UKMET all develop this)

[Gustywind]

Tropical Weather Discussion http://www.crownweather.com/?page_id=325
Issued: Saturday, August 28, 2010 815 am EDT/715 am CDT

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Discussion

Invest 97-L/Fiona In The Far Eastern Atlantic:
Now for Invest 97-L which will likely become Tropical Depression 8 and then Fiona over the next few days. This system is a broad area of low pressure located about 200 miles southwest of the Cape Verde Islands this morning. Invest 97-L continues to become better organized and I suspect we will see it upgraded to Tropical Depression 8 sometime this weekend. The track model guidance continues to shift further south with each model cycle and I suspect we will see further track model shifts to the south this weekend. As for strengthening, given the favorable environmental conditions, I suspect we will have Tropical Storm Fiona probably late Monday or early Tuesday and then Hurricane Fiona by around Wednesday. In the long range, the GFS and European model differ on the amount of strengthening with the GFS model forecasting a weak system that becomes entrained into the circulation of Earl. As I mentioned earlier, I don’t believe the GFS model’s forecast of this happening and instead I think this system will keep its distance from Earl and develop and intensify. The European model continues to be downright scary in terms of how intense it forecasts this system to become. It forecasts 97L/Fiona to have a central pressure of 941 millibars next Sunday and 934 millibars on Labor Day. This would be equivalent to a Category 4 hurricane.

The forecast track of 97L/Fiona posed by the global model guidance is very worrisome. The European model implies an ultimate strike from eastern North Carolina northward into the Mid-Atlantic States around Labor Day. The Canadian model implies a close brush with the outer banks of North Carolina on Labor Day. Now, it should be noted that the European ensemble models are further south than the operational model and imply a landfall somewhere on the South Carolina coast on Labor Day.

Now, let’s not forget the islands of the northeast Caribbean. This area may also be looking at a very real threat from this system around Wednesday. So, all interests in the islands of the northeast Caribbean should be aware that you may be looking at impacts from two separate tropical cyclones within two or three days.

Let’s look at how the overall weather pattern may setup for next week into the Labor Day weekend. A ridge of high pressure is currently setting up to the south of the Aleutian Islands with a trough of low pressure over the eastern Gulf of Alaska and into western Canada. This in turn forces high pressure to build over southeastern Canada and into the northeastern United States. So, the result may be that 97L/Fiona may be trapped from curving out into the open Atlantic and instead be directed right into the US East Coast during the Labor Day weekend. If I were to make an educated guess, I would say that based on the overall synoptic setup forecast for next week into the Labor Day weekend, the highest risk area for a hit from 97L/Fiona would be from South Carolina northward to Virginia. With that said, this is a very early educated guess and a lot can change. This does have the look of a classic US East Coast threat.

Obviously this potential threat is a long, long ways out, however, this system will be monitored extremely closely and I will keep you all updated. As I mentioned yesterday, don’t cancel your Labor Day weekend plans just yet as this threat is still way, way out there and a lot can change between now and next weekend.

The next tropical weather discussion will be issued sometime on Sunday morning.

Disclaimer: All forecasts herein are made to the best ability of the forecaster. However, due to standard forecasting error, these forecasts cannot be guaranteed. Any action or inaction taken by users of this forecast is the sole responsibility of that user.