Tropical Wave in East Atlantic (Is Invest 97L)

[SoupBone]

Do they run any separate modeling for high pressure over the U.S.? If so, what is it showing in place?

[Steve]

Ridge over Florida breaking down at 234 hours

Yeah, almost no chance of that at that timeframe. I could see the solution a few days later, but unless some oddball low pressure feature materializes in the temperate regions, I'd give the current GFS solution about 10% in that time frame.

[Caneman12]

I am just gonna point out something the long range 150 plus hours for the GFS consistently overdoes troughs it always has and it always under dues the ridge something to note also usually it has a northern bias the end of the latest Euro run shows a ridge building back in i am with the model that is good on track

[USTropics]

Looks like landfall somewhere between Panama City Beach and Port St. Joe, booking it north:

[StormClouds63]

Heads right up the east coast after landfall. A lot of population affected if this run were to verify.

[gatorcane]

I am just gonna point out something the long range 150 plus hours for the GFS consistently overdoes troughs it always has and it always under dues the ridge something to note also usually it has a northern bias the end of the latest Euro run shows a ridge building back in i am with the model that is good on track

Well the 10 day Euro doesn't show much ridging left over Florida or the Gulf, less than what the GFS shows. So perhaps the cyclone would slowly move north or NNW on that Euro run if we extended it out. It is all long-range and we know things are not accurate that far out.

[Caneman12]

I am just gonna point out something the long range 150 plus hours for the GFS consistently overdoes troughs it always has and it always under dues the ridge something to note also usually it has a northern bias the end of the latest Euro run shows a ridge building back in i am with the model that is good on track

Well the 10 day Euro doesn't show much ridging left over Florida or the Gulf, less than what the GFS shows. So perhaps the cyclone would slowly move north on that Euro run if we extended it out. It is all long-range and we know things are not accurate that far out.

Actually at the end of the Euro a ridge builds back in which would cause it to go back west but too far out.

[Blown Away]

I am just gonna point out something the long range 150 plus hours for the GFS consistently overdoes troughs it always has and it always under dues the ridge something to note also usually it has a northern bias the end of the latest Euro run shows a ridge building back in i am with the model that is good on track

Well the 10 day Euro doesn't show much ridging left over Florida or the Gulf, less than what the GFS shows. So perhaps the cyclone would slowly move north on that Euro run if we extended it out. It is all long-range and we know things are not accurate that far out.

After landfall seems to head NNE over SE CONUS and exit out @New York... No sharp NE turn...

[USTropics]

One reason the models are really latching onto P39L is an expected convectively-coupled equatorial Kelvin wave (CCKW) passing through the region, lowering shear in the area. The MJO is also forecasted to be favorable.

[Steve]

I am just gonna point out something the long range 150 plus hours for the GFS consistently overdoes troughs it always has and it always under dues the ridge something to note also usually it has a northern bias the end of the latest Euro run shows a ridge building back in i am with the model that is good on track

Well the 10 day Euro doesn't show much ridging left over Florida or the Gulf, less than what the GFS shows. So perhaps the cyclone would slowly move north on that Euro run if we extended it out. It is all long-range and we know things are not accurate that far out.

Actually at the end of the Euro a ridge builds back in which would cause it to go back west but too far out.

It is. But again the telegraph is already there in the WPAC. There will almost assuredly not be a trough on the US East Coast next weekend early into the following week. At some point after that one will be there, 7-10 days, almost no chance. 4-6 days probably does have one as the first high moves out.

Where the GFS I think gets this wrong is that the second high is centered too far north.

[GCANE]

GFS 350K PV Forecast shows a sudden clearing out of an PV anomolies as this enters the east Carib and stays very conducive for intensification as it travels the Carib.
http://tc.met.psu.edu/tcgengifs/GFS/201 ... 350PV.anim
Once in the GOM, a very large area clears out allowing for even further intensification pretty much anywhere it could potentially track.
IMHO given the momentum it will likely pick up in the Carib, any loss of vorticity if it travels over Cuba or the Yucatan will be regained quickly in the GOM.
This looks very likely for a major in the GOM at this point as pretty much all operational models are now indicating.

[Emmett_Brown]

The big eye opener IMO on the 18z GFS was that it's near Jamaica in just 186 hours. Edit, actually, the 12z Euro brings it to a similar longitude by 12z 10/02, so maybe the GFS is not that far out there, it's just a bit further north at that time.

[Hypercane_Kyle]

One reason the models are really latching onto P39L is an expected convectively-coupled equatorial Kelvin wave (CCKW) passing through the region, lowering shear in the area. The MJO is also forecasted to be favorable.

If this occurs then it would be a very favorable environment for upward motion, whereas with Hermine we saw a lot of downward motion that made the system struggle (that and persistent wind shear).

[cycloneye]

Here is the discussion from the pouch group about why they now add pouch 43L for the system the models develop.

** WARNING: Previous forecasts of a fast westward P39L now being replaced with a slow forecast for P39L and the initiation of this P43L as the separate, fast pouch. Part of the reason for this interpretation change is a shift toward the consistent GFS two-pouch solution in today’s ECMWF. **

[GCANE]

Currently sitting under an anti-cyclone

http://tropic.ssec.wisc.edu/real-time/e ... wm7shr.GIF

SYNOPSIS 2016092400

P43L
12N, 25W
700 hPa

http://met.nps.edu/~mtmontgo/synopses20 ... 092400.txt

** WARNING: Previous forecasts of a fast westward P39L now being replaced with a slow forecast for P39L and the initiation of this P43L as the separate, fast pouch. Part of the reason for this interpretation change is a shift toward the consistent GFS two-pouch solution in today’s ECMWF. **

Used 24-120 hours in both models for phase speeds.

ECMWF: Initially, simply an area of positive OW initially on the northern side of the large P39L/soon-to-be-P43L complex. Tracks quickly to the WSW for a couple days, with no CL-trough intersection until 60 hours. Then, finally as a separate pouch, P43L intensifies, with OW increasing from below zero at 60 hours to 12x10-9 s-2 at 120 hours near 13N, 62W.

GFS: Very uncertain positions on the north and northwest side of the P39L/P43L complex for the first 12 hours, then a separate, larger P43L is depicted by 24 hours (sooner than in ECMWF, which is no surprise since GFS has been hinting at this two-pouch solution for a couple days now).

[cycloneye]

Up to 70% in 5 days

A tropical wave, accompanied by a broad area of low pressure, is
located several hundred miles southwest of the Cabo Verde Islands.
This disturbance is expected to move rapidly westward across the
tropical Atlantic Ocean at 20 to 25 mph for the next several days.
Environmental conditions are expected to become conducive for
gradual development as the system moves into the western tropical
Atlantic early next week, and a tropical depression could form
while the system approaches the Lesser Antilles and moves into the
Caribbean Sea by the middle of next week.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...high...70 percent

[fci]

I was surprised this afternoon when it was 60% chance in 5 days and not tagged so they up it to 70% and still not an Invest......

[Kazmit]

How is it still not an invest if it has a high (70%) chance of developing?

[SFLcane]

Wow 70% no invest ... concerning trend here for FLorida BUT longggggggg time to go.

[RL3AO]

They've generally tagged invests once they get to 20 or 30% within two days.