2015 Global model runs discussion

[gatorcane]

One other thing that is a bit interesting is that the ECMWF ensembles are now depicting a weak area of below normal pressure traversing the MDR and actually has it around the area the GFS has it at 192 hours:

[CrazyC83]

Could a Cape Verde storm develop farther north - say around the islands or north of them in the 20-25N region - and actually survive for a while?

[Hammy]

Could a Cape Verde storm develop farther north - say around the islands or north of them in the 20-25N region - and actually survive for a while?

At least a few I can think of
http://weather.unisys.com/hurricane/atlantic/1992/CHARLEY/track.gif
http://www.atmos.albany.edu/student/ppapin/maps/gridsat/1992/atl/ir_sat_atl_9_152.png
Charley and it's wave in 1992

http://weather.unisys.com/hurricane/atlantic/2012/GORDON/track.gif
http://weather.unisys.com/hurricane/atlantic/2003/DANNY/track.gif
two more examples more recently.

[Hammy]

GFS dropped it of course and now shows nothing developing until near the end of the month (which at this point essentially means nothing will form until the first or second week of September.)

[Alyono]

will be very surprised if anything were to form in August.

To be honest, I only expect 1 or 2 more storms the remainder of the year. Conditions are simply too hostile

[gatorcane]

The ECMWF is showing a Cape Verde storm on the 12Z run for Aug 23rd but it is in the long-range:

[gatorcane]

Other model updates:

NAVGEM is still liking the Cape Verde storm:


Nice to see the CMC is back spinning up phantom storms (in the Caribbean this time):

[tailgater]

Wow August 13, and all the entire globe can offer up is 1 TD and 3 little invest.

[Siker]

Wow August 13, and all the entire globe can offer up is 1 TD and 3 little invest.

To be fair, two of those invests are poised to become Category 5's.

[gatorcane]

Looking at the GFS runs today, it has not completely dropped this system. In fact the latest 18Z run that just ran shows a 1008-1010MB closed low that heads west across the MDR where it remains in tact through the Leewards/Eastern Caribbean and eventually into the Bahamas and Florida after that way out in the long-range. In fact it shows a sharp increase in convection as it moves into the Leewards, something we haven't seen any of the previous model runs do with waves heading west so far this season:

18Z GFS 10 day graphic below, with the low around the leewards:


The NAVGEM is more bullish on the 18Z run too but deepens more quickly than the GFS and turns it NW:

[Hurricaneman]

and not to mention the 12 EURO has a sharp surface wave near the Bahamas from that system at day 10

[floridasun78]

can you post 12 EURO show sharp surface wave near the Bahamas from that system at day 10???

[Hurricaneman]

Its the 2nd one on the page

[Siker]

00z Euro keeps its Cape Verde depression in the long range.

[Hammy]

http://www.tropicaltidbits.com/analysis/models/ecmwf/2015081400/ecmwf_mslp_uv850_atl_6.png
Euro shows a TD off of Africa in 120 hours, but dissipates it a few days later, with the second system reaching storm intensity in 240 hours.
http://www.tropicaltidbits.com/analysis/models/ecmwf/2015081400/ecmwf_mslp_uv850_atl_11.png

A few things stick out here: the first being that these are fairly close together, and I wonder if its possible that they interfere with each other and neither develop. The other possibility is that the first system acts as a humidifier for the second system.

The other question for any of the pro-mets is, can this model be trusted at all now after the fiasco with the trough at the end of July.

Comparing this run to the other models, the GFS develops the first system in 72-96 hours (gee, where have I seen this happen before), takes it into the Caribbean as either a weak storm or wave, and seems to send it up towards Florida (pure fantasy land, but the first system it's shown making it all the way across so it at least bears watching) but does not develop the Euro's system until 288 hours (in roughly the same place, but it appears to move it more slowly.)


Canadian develops the GFS's system in little under a week and moves it into the Caribbean, and south of Jamaica by 240 hours. It develops the Euro's system a bit earlier, but also shows two lows simultaneously (more so than the Euro) and keeps both fairly weak.

Navy model develops same system as Canadian, but keeps it much more broad and takes it further north, and shows a large gyre moving off at 180 hours.

If nothing else, this is at least the first model consensus that has occurred in the MDR this season, and seems to coincide with the arrival of the MJO as per the CPC outlook.

[tolakram]

GFS is showing a slightly better mid level environment at 192 hours but not by much. This is the time of year you would expect to see CV activity, and back to back systems, with the leading system improving the environment for the second system, is fairly typical.


... but I don't believe it.

[gatorcane]

Long-range ECMWF day 10 continues to show a Cape Verde storm:

[blp]

Very good blog today by Bob Henson about the model upgrades and the Intensity forecasts.

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3072

[TheStormExpert]

Like to see several more runs of the Euro showing the storm before I become somewhat more interested.

[Ntxw]

From the guidance as well there is wall to wall anomalous shear from the Caribbean to the eastern Atlantic. These "modeled" waves will have to develop quickly as soon as they come off in order to survive otherwise if they wait too far west it will be a much tougher path.