GaWx

Despite the noted tendency for the GFS to be too far right with recurving TCs, it was interestingly enough way too far LEFT with both of the 2022 Ian SE US landfalls and also too far left with last month's Idalia FL landfall. Thus I'm wondering if the GFS really still has a too far right bias for recurves and instead now has a net neutral or possibly even a left bias: 1. FL Ian landfall 1-4 days out: - GFS was still way up at Apalachee Bay just 68 hours from landfall (0Z 9/26 run) vs the actual Port Charlotte (PC) landfall point. That's a 200 mile error to the left at just 68 hours out! - At that point, UKMET was dead-on at PC and ICON was at Venice, only 25 miles from PC. - GFS wasn't close to PC until the 12Z 9/27 run, just 32 hours out. Until then it was too far left on all runs out going back at least several days: 2. SC Ian landfall 1-4 days out: - GFS was still way down at Hilton Head just 54 hours from landfall (12Z 9/28 run). That's 100 miles to the left of the actual track. - GFS wasn't close to the actual landfall location of Georgetown until the 12Z 9/29 run, just 30 hours out. Until then it was too far left on all runs out going back at least several days: 3. FL Idalia landfall: - GFS was on the left side of the model consensus for several days of runs before landfall and about as far left as any - Just 30 hours out with the 8/29 6Z run, the GFS was still 50 miles too far left of the actual landfall - The Euro and ICON were almost always to the right of the GFS (as well as much closer to the actual track), and the UKMET was usually to the right of the GFS.

9/14 18Z EPS had a mere two (4%) US landfalling members and they were on the far E end of ME. It's looking very good for no US landfall. 9/15 0Z UKMET into SW NS PM of 9/16

I saw this paper before. It may increase the chance for a multi-year Nino during 2025-9. A good hint of this is warm NW/cool SE in N America in DJF, rather typical of El Niño. Also, note the cold Scandinavia and Australia in winter. One of the reasons for the cool anomalies appears to be heavier than normal precip related if I'm recalling correctly as the volcano itself apparently favors net increased global warmth.

What are the implications of "huge amounts of water vapor" in NH polar cap as regards the most likely effects on E US winters over the next 5 years or so? Do you have any idea based on what experts are saying? If so, please answer this as objectively as possible. Based on you making a post about this, I'm assuming you think there are potentially significant implications. TIA

9/14 12Z: 11 (22%) 10 ME, 1 MA (CC) So, the 12Z EPS had an increase in ME along with one MA outlier, but this still suggests a high chance (78%) for no US landfall. So, I'm going with no US landfall.

OHC per this graph dropping back some more to <+1.2:

-Out of twelve 0Z models including the 4 tropical models and excluding the NAM, the only one showing a US landfall is the lowly JMA (central ME). And the JMA shifted away from Cape Cod since 12Z. How far off does this 0Z JMA, even after its significant NE shift, appear to be? It is to the left of all 51 members of the last three EPS runs ending with today's 6Z run: -Recent EPS Runs' US Landfalls: going down 9/14 6Z: 6 (12%) 6 ME 9/14 0Z: 7 (14%) 7 ME 9/13 18Z: 10 (20%) 10 ME 9/13 12Z: 14 (27%) 13 ME, 1 MA 9/13 6Z: 35 (69%) 27 ME, 6 MA, 2 RI 9/12 18Z: 36 (71%) 21 ME, 9 MA, 3 RI, 3 NY (LI)

0Z run landfalls: -Arpege: SW NS early 9/16 968 mb (faster and E shift vs 12Z's NB) -ICON: NB early 9/17 981 mb (similar to 12Z) -GFS: NB early 9/17 976 mb (similar to 12Z) -CMC: SW NS late 9/16 980 mb (slight W shift vs 12Z) -UKMET: SW NS late 9/16 970 mb (slight E shift vs 12Z) -JMA (inferior): C ME early 9/17 973 mb (NE shift vs 12Z, which crossed CC) -Euro: NB early 9/17 976 mb (similar to 12Z) -KMA: SW NS midday 9/16 ~960 mb (big E shift vs 12Z's E ME)

The NAM is a horrible model to use for the tropics. That being said, the JMA may not be all that much better and I still post about it.

Agreed. The past five days have averaged for NE US landfalls ~25-30% on the EPS and ~20% on the GEFS. So, under 25% for the two, combined. Also, the GEPS (considered inferior and thus not as closely followed) has had a significantly lower % than the GEFS. Many of those runs had no more than 1-2 hits (10% or lower). So, yes, the totality of the GEFS/EPS/GEPS suggested about a four times better chance of no US landfall vs a landfall. But of course, it is easy to hindsight. Next time may be different. Just going with the 1 out of 5 chance for a landfall, the next time may be one of those 20%. And we shouldn't forget that there still is a chance at a ME landfall with Lee.

A bit more than that for the ensemble runs. Yesterday's 18Z EPS was the peak with ~70% NE US landfalls with 30% (15 members) just for NE US excluding Maine. At least two other EPS runs since yesterday had ~50% landfalling in New England. The GEFS for NE US landfalls peaked at over 40% on one run three days ago and also had a run over 30% two days ago. But since yesterday, it has been mainly ~20% or less. Thus the EPS peaked after the GEFS backed down.

Indeed as expected, Aug of 2023 of ~29.7 is 2nd warmest for Nino 4 since 1950. So, that point should be emphasized. The current +1.3 in Nino 4 is pretty impressive. But OTOH beside the current strong Nino, the graph clearly shows that it's getting a good boost from more general warming. Since 1980, it has trended up ~1C. After taking that trend into account, the 29.7 is arguably less impressive than the 29.4 of 1987 and the 29.5 of 1994 and about on par with the 28.8 of 1982, the 29.25 of 1991, the 29.3 of 1997, and the 29.45 of 2002.

On OISST, Nino 3.4 (nearly +1.7) and Nino 4 (nearly +1.2) are at new highs while Nino 3 is about tied for the high (nearly +2.3). Nino 1+2 bounced back some (to nearly +2.9) as a correction as expected after its recent plunge.

UKMET has also done pretty well overall with the tropics for track (not intensity though). It was doing the best for Lee with the Euro second best as per graphs that were posted earlier. Also, it did great for Ian last year as regards both the FL and SC landfalls and I think it was pretty good for Idalia.

Did he drop his 920 mb peak restrengthening prediction yet? The lowest it got back down to was 946 mb per NHC advisories.

12Z Euro landfall NB hour 90 early 9/17 974 mb

12Z Euro landfall NB hour 90 early 9/17 974 mb

Some 12Z run landfalls: -Arpege: NB very late 9/16 980 mb -ICON: NB early 9/17 975 mb -GFS: NB early 9/17 976 mb -CMC: SW NS early 9/17 981 mb -UKMET: SW NS late 9/16 966 mb

Some 12Z run landfalls: -Arpege: NB very late 9/16 980 mb -ICON: NB early 9/17 975 mb -GFS: NB early 9/17 976 mb -CMC: SW NS early 9/17 981 mb -UKMET: SW NS late 9/16 966 mb -JMA: Cape Cod 8PM 9/16 963 mb -Euro: NB hour 90 early 9/17 974 mb -KMA: E corner ME 5PM on 9/16 962 mb

0Z Euro landfall E ME at 102 hours very early 9/17 975 mb

0Z Euro 96 close to 12Z Euro 108 after passing 100 miles E of CC

0Z Euro 72 is 75 miles NW of 12Z 84

0Z JMA tracks just E of Cape Cod to landfall WC ME late 9/16.

Meteo-France's Arpege big shift W from 12Z's Bay of Fundy/NB to 0Z's C ME

Some more 0Z runs: -Meteo-France big shift W from 12Z's Bay of Fundy/NB to 0Z's C ME -ICON similar to last two runs into SW NS early 9/17 973 mb -CMC 75 mile W shift to W NS at 988 mb early 9/17 -0Z JMA tracks just E of Cape Cod to landfall WC ME late 9/16 (slightly E of 12Z, which was on Cape Cod) 0Z Euro landfall E ME at 102 hours very early 9/17 975 mb