Global model runs discussion

[ninel conde]

GFS ensembles picking up activity on long range.

http://oi44.tinypic.com/2m3pute.jpg

http://oi41.tinypic.com/15e7bkp.jpg

i dont see any activity. can you explain?

[cycloneye]

GFS ensembles picking up activity on long range.

http://oi44.tinypic.com/2m3pute.jpg

http://oi41.tinypic.com/15e7bkp.jpg

i dont see any activity. can you explain?

I will let Levi Cowan explain his graphic. He posted in another board.

Single CFS runs don't mean much, but if you take a whole slew of them, you can tell if the model is showing a significant change in conditions. If you take the last 48 forecasts of the CFS for 25 days from now (August 8), you see many lows populating the MDR east of the Caribbean, with some passing north of the Antilles. Every red number is a closed low on one of the 48 runs.

[Dean4Storms]

GFS ensembles picking up activity on long range.

http://oi44.tinypic.com/2m3pute.jpg

http://oi41.tinypic.com/15e7bkp.jpg

i dont see any activity. can you explain?

All those little red numbers in the MDR are each individual ensemble members depictions of Lows. The yellow shading depicts overall lowering of pressures in the areas. When you see that many lows forecast for the MDR and lowering areas of pressure it simply is forecasting heightened chances of something developing, it's not actually showing in these maps an individual storm.

Hope this helps, best I can explain simplified. Maybe someone else can do better.

[TropicalAnalystwx13]

The GFS is being overzealous on the strength and location of the MJO pulse as it typically is, so I'd look for the time frame of the cyclone it's depicting to be pushed back some. Watch the first week of August and /especially/ thereafter.

[Hurricaneman]

The GFS has been persistent in developing a wave coming off of africa at day 10 so that needs to be watched the next few days in whether it keeps development a week from now or it completely drops it, and the wave currently coming off of africa has a chance according to the GFS

[cycloneye]

00z GFS continues the trend of the prior 3 runs developing a wave in 10 days. This is not the pouch PO9L that is about to emerge but the one behind. Here it is at 384 hours or fantasy territory.



Pouch PO9L is this wave that 00z GFS has in 189 hours.

[TreasureIslandFLGal]

Looks to me like the GFS is setting up a very weak ridge into the end of the month. Well, not weak, but significantly located/centered to the northeast in the Atlantic, making its west side periphery relatively weak and withdrawn into the atlantic.
If that is the "set up" for ridging during the meat of the season, it looks likek there would be a lot of recurves, rather than CONUS hits of CV systems.
Lately the ridge's west side has extended either over Florida, or just off the east coast --which would favor a pattern of either FL or Gulf bound storms.
Of course things can and do change...but if that is the setup the GFS is presenting, that appears to be good news for the US. Will need to continue to watch developing hurricane season pattern and see what the other models start predicting.

[TropicalAnalystwx13]

Looks to me like the GFS is setting up a very weak ridge into the end of the month. Well, not weak, but significantly located/centered to the northeast in the Atlantic, making its west side periphery relatively weak and withdrawn into the atlantic.
If that is the "set up" for ridging during the meat of the season, it looks likek there would be a lot of recurves, rather than CONUS hits of CV systems.
Lately the ridge's west side has extended either over Florida, or just off the east coast --which would favor a pattern of either FL or Gulf bound storms.
Of course things can and do change...but if that is the setup the GFS is presenting, that appears to be good news for the US. Will need to continue to watch developing hurricane season pattern and see what the other models start predicting.

That's nothing new. The Azores high has been shifted far, far northeast for a while now, it's just very potent. It still has a large influence across the Atlantic at the end of the GFS run, and in fact, it's reinforced by an area of high pressure near Newfoundland, something picked up by models for the ASO period months ago. Doesn't favor recurvatures much at all.

[ninel conde]

still, its only showing a 1006 low. the low over africa is deeper.

[NDG]

Looks to me like the GFS is setting up a very weak ridge into the end of the month. Well, not weak, but significantly located/centered to the northeast in the Atlantic, making its west side periphery relatively weak and withdrawn into the atlantic.
If that is the "set up" for ridging during the meat of the season, it looks likek there would be a lot of recurves, rather than CONUS hits of CV systems.
Lately the ridge's west side has extended either over Florida, or just off the east coast --which would favor a pattern of either FL or Gulf bound storms.
Of course things can and do change...but if that is the setup the GFS is presenting, that appears to be good news for the US. Will need to continue to watch developing hurricane season pattern and see what the other models start predicting.

Ridging across the subtropical Atlantic and NW Atlantic has been fairly strong for the past 2-3 months and I do not see a change in that over the next couple of months if not longer.
As we get into August and September you usually see a weakness of the Atlantic ridge "at the surface", or in another words lowering of surface pressures but ridging in the mid levels stay fairly strong, which is what steers the tropical systems.
I do not see much recurvetures this hurricane season if present mean conditions persists.

GFS Ensembles continue to show strong mid level ridging across the Atlantic through the end of the month, more often than not:

http://www.esrl.noaa.gov/psd/map/images ... ation.html

[SFLcane]

12z GFS (long-range) this afternoon once again has little to know ridgeing of the southeast which at that point any capeverde storm will most certainly recurve.

[cycloneye]

12z GFS (long-range) this afternoon once again has little to know ridgeing of the southeast which at that point any capeverde storm will most certainly recurve.

IMO,that is a pretty pronounced weakeness of the Bermuda High. Let's see down the road how the pattern evolves as August arrives in two weeks.

[SouthFloridawx]

12z GFS (long-range) this afternoon once again has little to know ridgeing of the southeast which at that point any capeverde storm will most certainly recurve.

IMO,that is a pretty pronounced weakeness of the Bermuda High. Let's see down the road how the pattern evolves as August arrives in two weeks.
[img]http://oi40.tinypic.com/zvewhz.jpg

Pretty far out to start judging that I'd say. We'll have to see if this continues on more runs in the future.

[Bocadude85]

12z GFS (long-range) this afternoon once again has little to know ridgeing of the southeast which at that point any capeverde storm will most certainly recurve.

IMO,that is a pretty pronounced weakeness of the Bermuda High. Let's see down the road how the pattern evolves as August arrives in two weeks.

Every season features a time when the ridge weakens and breaks down, doesn't mean the ridge won't build back in. August 2004 featured a weakness along the Southeast US Coast only to be replaced by ridging in September, and we all know how that season turned out. I doubt we will know what the pattern will be until we enter the first and second week of August.

[SouthFloridawx]

Should we be watching the Ridging on the 500mb Chart as well? Surface Ridging is not solely responsible for the steering of a system. What do you guys think?


Replaced Image to match 360HR

[Ntxw]

200+ hours of models runs won't get the pattern right, if it does it's mostly pure luck, even the strongest ridges can split temporarily or hold intact for short periods of time. We need to first identify a legit storm threat. Doesn't seem like any for awhile. I still like the second half of August seems best with climo and MJO timing.

[cycloneye]

Yeah really? Thankfully is the 18z run and is long range.

[blp]

Heads up!! Cycloneye. Ridge stronger on this run which keeps it further south early on. Weakness looks like it may fill in quicker on that run.

[cycloneye]

Heads up!! Cycloneye. Ridge stronger on this run which keeps it further south early on. Weakness looks like it may fill in quicker on that run.

http://imageshack.us/a/img27/6606/81ut.jpg

Is the first run that has it very strong so the 00z will be interesting to see if it continues with it and to see how the ridge is.

[blp]

Heads up!! Cycloneye. Ridge stronger on this run which keeps it further south early on. Weakness looks like it may fill in quicker on that run.

http://imageshack.us/a/img27/6606/81ut.jpg

Is the first run that has it very strong so the 00z will be interesting to see if it continues with it and to see how the ridge is.

Yes sir 974mb on that image you posted. Also Canadian agrees with GFS at 240hr.

12z Canadian