ATL: EARL - Models

[Riptide]

It really does look like trailing Fiona helps to erode the western edge of the ridge, allowing Earl to find a weakness. That is my theory on this model run.

[KWT]

You've gotta look at the upper flow ISC...

The truth is whilst there is a upper ridge its centered over the E.coastal states of the US, then as the upper troughing comes along the whole thing deflates pretty much and shifts to the west from the looks of things.

The high looks strong, but believe me its not really that strong and could erode pretty quickly even if there is only weak upper troughing coming along...thats why run after run keeps recurving, because there is just too much troughing and the pattern is too progressive...in other words no sooner is one upper trough and weakness gone, 2-3 days later a new one develops over Canada and moves eastwards. The combo of Upper level Troughs over E.Canada and Upper high pressure to the south over the E.Coast means a E.coast hit is VERY hard to come by, not impossible but its certainly the outside risk...

Its also why I was so sure about Danielle recurving in the last 2 weeks, because that pattern rarely leads to a US threat.

[gatorcane]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

24 hours later since my last post on this thread and not a whole lot has changed. Models trended a bit more left today so the threat to the islands has increased but not by alot. Still calling for Earl to miss the islands to the NE and recurve east of the Bahamas and U.S. Reasons are the same as before. Until I see the GFS and ECMWF not bend NW at the end, still looks fishy to me (barring a Bermuda hit of course).

[gatorcane]

One thing for amusement. Though the cone is bending NW at the end, there are examples of how the models have underestimated the strength of a ridge badly. Check out the 5-day cone loop of Ike which kept getting pushed more and more west (the curve NW did not happen until it got into the Western GOM though it was supposed to hit a weakness in the Bahamas at one point. That is nearly a 1000 mile error). Of note, the GFDL did forecast a large ridge and did very well with this system.

http://www.nhc.noaa.gov/archive/2008/gr ... p_5W.shtml

So though I do think it should curve away from the SE US and probably CONUS all together, I am not completely sure yet. It's too early to call. Curiously the 18Z GFS shows only a very weak shortwave traversing Southern Canada, so its not alot to break the ridge if the ridge is stronger than the models are forecasting.

[OuterBanker]

18z was a lot more south but a lot more east. Back to normal.

I thought that 12z was too far west.

Just an outlier as I thought.

Looks like the strong troughing this year will help protect the east coast from CV storms.

A good thing.

[Typhoon_Willie]

Well Gatorcane that loop just illustrates the fact that when it comes to the models one has to monitor the trends they may be showing.

[cycloneye]

00z Tropical Models

Code: Select all

WHXX01 KWBC 270034
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0034 UTC FRI AUG 27 2010
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
TROPICAL CYCLONE EARL (AL072010) 20100827 0000 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        100827  0000   100827  1200   100828  0000   100828  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    15.6N  39.6W   16.2N  42.6W   17.0N  45.8W   18.0N  49.4W
BAMD    15.6N  39.6W   16.3N  42.4W   16.9N  45.4W   17.4N  48.7W
BAMM    15.6N  39.6W   16.4N  42.6W   17.2N  45.9W   18.1N  49.7W
LBAR    15.6N  39.6W   16.4N  42.6W   17.2N  46.0W   17.9N  49.8W
SHIP        40KTS          45KTS          53KTS          60KTS
DSHP        40KTS          45KTS          53KTS          60KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        100829  0000   100830  0000   100831  0000   100901  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    19.4N  53.3W   22.2N  59.7W   24.1N  64.7W   24.0N  70.0W
BAMD    18.0N  52.0W   19.2N  57.9W   20.9N  61.8W   24.2N  65.3W
BAMM    18.9N  53.4W   20.6N  59.4W   22.1N  63.4W   24.0N  67.0W
LBAR    18.7N  53.4W   19.8N  58.7W   20.8N  61.8W   23.9N  65.2W
SHIP        68KTS          76KTS          86KTS          91KTS
DSHP        68KTS          76KTS          86KTS          91KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  15.6N LONCUR =  39.6W DIRCUR = 280DEG SPDCUR =  16KT
LATM12 =  14.9N LONM12 =  36.3W DIRM12 = 281DEG SPDM12 =  16KT
LATM24 =  14.5N LONM24 =  33.3W
WNDCUR =   40KT RMAXWD =   60NM WNDM12 =   40KT
CENPRS = 1003MB OUTPRS = 1012MB OUTRAD =  225NM SDEPTH =   M
RD34NE =   75NM RD34SE =   60NM RD34SW =    0NM RD34NW =  75NM

[Blown Away]

Pretty healthy west shift for the 00Z BAM's.

[Riptide]

00z Tropical Models

Code: Select all

WHXX01 KWBC 270034
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0034 UTC FRI AUG 27 2010
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
TROPICAL CYCLONE EARL (AL072010) 20100827 0000 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        100827  0000   100827  1200   100828  0000   100828  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    15.6N  39.6W   16.2N  42.6W   17.0N  45.8W   18.0N  49.4W
BAMD    15.6N  39.6W   16.3N  42.4W   16.9N  45.4W   17.4N  48.7W
BAMM    15.6N  39.6W   16.4N  42.6W   17.2N  45.9W   18.1N  49.7W
LBAR    15.6N  39.6W   16.4N  42.6W   17.2N  46.0W   17.9N  49.8W
SHIP        40KTS          45KTS          53KTS          60KTS
DSHP        40KTS          45KTS          53KTS          60KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        100829  0000   100830  0000   100831  0000   100901  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    19.4N  53.3W   22.2N  59.7W   24.1N  64.7W   24.0N  70.0W
BAMD    18.0N  52.0W   19.2N  57.9W   20.9N  61.8W   24.2N  65.3W
BAMM    18.9N  53.4W   20.6N  59.4W   22.1N  63.4W   24.0N  67.0W
LBAR    18.7N  53.4W   19.8N  58.7W   20.8N  61.8W   23.9N  65.2W
SHIP        68KTS          76KTS          86KTS          91KTS
DSHP        68KTS          76KTS          86KTS          91KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  15.6N LONCUR =  39.6W DIRCUR = 280DEG SPDCUR =  16KT
LATM12 =  14.9N LONM12 =  36.3W DIRM12 = 281DEG SPDM12 =  16KT
LATM24 =  14.5N LONM24 =  33.3W
WNDCUR =   40KT RMAXWD =   60NM WNDM12 =   40KT
CENPRS = 1003MB OUTPRS = 1012MB OUTRAD =  225NM SDEPTH =   M
RD34NE =   75NM RD34SE =   60NM RD34SW =    0NM RD34NW =  75NM

[img]http://my.sfwmd.gov/sfwmd/common/images/weather/plots/storm_07.gif

Wow, it looks like the Hebert box is highlighted.

[KWT]

Models still shifting westwards but I don't really think there is much more westward mileage left ig the models now and they should be starting to get fairly close to the final end game, which IMO is something close to 70W.

[Emmett_Brown]

Ok, mods, sorry for quoting the image, but bear with me... Thanks for posting this Gatorcane. To me, something is screwy with this map. There is clearly an H500 ridge over the E CONUS... and yet Earl is moving N at this point in time. It would appear that the wedging of Fiona next to Earl is causing a weakness to the E of Earl, which cancels out the W component of motion, and causes Earl to drift N slowly until inevitable recurve. So, the question is, what proximity will these storms have? If Earl can stay ahead of Fiona, I think he gains more longitude in this scenario.

[KWT]

Take a look further north Emmett, you've got an upper trough moving through to the north...its weak but remember its all relative with heights....there is no closed upper ridge at all, at best its a very flabby region of slightly higher background heights centered over the states but make no doubts about it for this part of the ocean the upper troughs are what is driving the pattern at the moment...

So when you have a weak upper ridge feature over the East coast, another even weaker ridge in the central Atlantic then inbetween the two your going to have a trough, which in this case is also weak but is enough to slowly lift Earl out...but its not a strong feature by any means.

Now if we get an upper high over Canada then things change but until that happens, I can't see any major shift in the pattern overall, just enough to allow maybe 10 degrees variation from 55-60W pattern we seem to be locked into...

[Emmett_Brown]

Take a look further north Emmett, you've got an upper trough moving through to the north...its weak but remember its all relative with heights....there is no closed upper ridge at all, at best its a very flabby region of slightly higher background heights centered over the states but make no doubts about it for this part of the ocean the upper troughs are what is driving the pattern at the moment...

So when you have a weak upper ridge feature over the East coast, another even weaker ridge in the central Atlantic then inbetween the two your going to have a trough, which in this case is also weak but is enough to slowly lift Earl out...but its not a strong feature by any means.

Now if we get an upper high over Canada then things change but until that happens, I can't see any major shift in the pattern overall, just enough to allow maybe 10 degrees variation from 55-60W pattern we seem to be locked into...

Good points KWT... you are right, the ridge is quite weak upon further inspection... I was probably making too much out of the shape of the ridge and overlooked the lack of solid isobars. The West trend of the models has been interesting, however.

[Riptide]

Take a look further north Emmett, you've got an upper trough moving through to the north...its weak but remember its all relative with heights....there is no closed upper ridge at all, at best its a very flabby region of slightly higher background heights centered over the states but make no doubts about it for this part of the ocean the upper troughs are what is driving the pattern at the moment...

So when you have a weak upper ridge feature over the East coast, another even weaker ridge in the central Atlantic then inbetween the two your going to have a trough, which in this case is also weak but is enough to slowly lift Earl out...but its not a strong feature by any means.

Now if we get an upper high over Canada then things change but until that happens, I can't see any major shift in the pattern overall, just enough to allow maybe 10 degrees variation from 55-60W pattern we seem to be locked into...

And like always, climatology favors recurve with early-forming CV systems. Same old song and dance...

[Emmett_Brown]

At some point, La Nina is going to show up in the upper pattern and send one of these West...

[ConvergenceZone]

And like always, climatology favors recurve with early-forming CV systems. Same old song and dance...

I agree, there's way too much troughiness out there to think that these storms are going to do anything but recurve.....


The models wars are fun though for entertainment.....

[ronjon]

The pattern is one in transition from troughing to ridging and I don't believe the models have caught up to it yet. The GFS shows mid level ridging expanding over the eastern USA and western Atlantic - a synoptic setup like Frances. Now the key is how much latitude Earl gains, how quickly the weakness by Danielle is filled, and utimately how strong the ridging becomes, and how long it lasts. Sometimes hurricanes tend to pump up the ridging so I think the door is still open for this one to move west.

[AtlanticWind]

I do think Earl is a likely recurve , but is not out of the question that this could change . models in the 5 to 8 day range are pretty good but they dont always pick up a pattern change.

[TheDreamTraveler]

Getting way too close for comfort. Especially seeing as how they have it becoming a major hurricane.

[Steve H.]

Ronjon, you're spot on. Eventually the pattern shift will conclude, and the east coast trough will give way to ridging. It will not be a good thing for us in the CONUS. We are starting to head into the meat of the season. Maybe not Earl, but 97l may take a shot west. And there is always the home brew.