GaWx

Followup to the above 12Z UKMET post regarding the new MDR AOI: I just looked at the last 4 UKMET runs and discovered that the reason the latest run recurves this AOI into Erin is because Erin is further SW due to a further W recurve and thus doesn’t exit until a couple of days later than yesterday’s runs:UKMET progs for 0Z 8/22:1) 0Z 8/15 run at 168 hrs:Erin 954 mb at 38N, 59W after recurve at 70WAOI 1011 mb at 20N, 61W, is 1,250 miles to the S2) 12Z 8/15 run at 156 hrs:Erin 949 mb at 42N, 57W after recurve at 70WAOI 1006 mb at 18N, 62W, is 1,700 miles to the SSW3) 0Z 8/16 run at 144 hrs:Erin 962 mb at 37N, 66W after recurve at 73WAOI 1007 mb at 16N, 59W, is 1,500 miles to the SSE4) 12Z 8/16 run at 132 hrs:Erin 958 mb at 35N, 71W after recurve at 74WAOI 1006 mb at 20N, 57W, is 1,350 miles to the SEmoving NW to the S of retreating H5 ridgeConclusion: It isn’t just about how fast the AOI moves W and develops, but also and possibly more crucially it is about how far W Erin recurves. The further W Erin recurves, the longer it will take for her to exit. The later the exit, the better chance the AOI would have to recurve before reaching the Conus.

Yes. I have no idea.

12Z UK has TS 3rd run in row but this recurves ~62W due to Erin to its N: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 102 HOURS FORECAST POSITION AT T+102 : 15.6N 48.6W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 21.08.2025 108 16.8N 50.3W 1009 26 1200UTC 21.08.2025 120 18.5N 54.0W 1008 31 0000UTC 22.08.2025 132 20.3N 56.7W 1006 31 1200UTC 22.08.2025 144 21.9N 59.3W 1005 36 0000UTC 23.08.2025 156 24.5N 61.2W 1006 35 1200UTC 23.08.2025 168 25.3N 61.8W 1006 38

Thunderstorms that popped up along the seabreeze have resulted in moderate to heavy rain here since 1:45. I’m >1” and adding to that. So, I’m >13” for MTD! Edit: I ended up with ~1.6” on 8/16. That gets me to a whopping ~13.6” for Aug 1-16! Some in the county got as much as ~3” around the Windsor Forest area.

1. 2024 (161 ACE) didn’t get 2nd major til late Sep. 2. 2023 (146) didn’t have 1st MH til 8/20. 3. 2021 (146) 1st MH 8/20. 4. 2020 (180) 8/26 5. 2019 (132) 8/30 6. 2018 (133) 9/10 7. 2017 (225) 8/25 8. 2016 (141) 8/30 ——— 2025 got 1st MH on 8/16. Seasons with 1st MH by 8/16: 2024, 2008, 2005, 2004, 2000, 1996, 1995…only 7 of last 30 (23%).

1. 2024 (161 ACE) didn’t get 2nd major til late Sep. 2. 2023 (146) didn’t have 1st MH til 8/20. 3. 2021 (146) 1st MH 8/20. 4. 2020 (180) 8/26 5. 2019 (132) 8/30 6. 2018 (133) 9/10 7. 2017 (225) 8/25 8. 2016 (141) 8/30 ——— 2025 got 1st MH on 8/16. Seasons with 1st MH by 8/16: 2024, 2008, 2005, 2004, 2000, 1996, 1995…only 7 of last 30 (23%). Edit: We don’t need another storm even near Erin’s incredible strength to end up with an AN ACE season. @snowman19

Due to Erin ACE is now rapidly rising with 2025 about to cross median for the date (of last 75) and should cross mean tomorrow. 2025 should reach top 20 for the date by Mon and top 15 or higher by Tue or Wed. @snowman19@mitchnick

Due to Erin ACE is now rapidly rising with 2025 about to cross median (of last 75) and should cross mean tomorrow. 2025 could reach top 20 by Mon and top 15 by Tue or Wed.

Is there any significance to the 2nd area of deep convection to the SW of the main area?

0Z UK is similar to the 12Z with a TS N of the Leewards moving WNW:NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 132 HOURSFORECAST POSITION AT T+132 : 15.6N 56.6WLEAD CENTRAL MAXIMUM WINDVERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)-------------- ---- -------- ------------- -------------1200UTC 21.08.2025 132 15.6N 56.6W 1009 260000UTC 22.08.2025 144 16.3N 58.8W 1007 321200UTC 22.08.2025 156 18.1N 60.9W 1006 370000UTC 23.08.2025 168 19.4N 63.3W 1005 38

Any chance his idea is the right one?

IF that happens, the seasonal ACE would reach ~34 as of 8/22. If then another multiday hurricane were to closely follow Erin like the GFS/GEFS are suggesting could occur, having 50ish ACE by the end of August would be a reasonable possibility especially considering there could easily abe an additional weaker storm or two, which would out 2025 notably above the normal ACE through August.

It’s getting dark in the N sky here and the radar says strong thunderstorms are on the way as an outflow boundary is coming through: SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHARLESTON SC 635 PM EDT FRI AUG 15 2025 GAZ118-119-SCZ047-051-152330- COASTAL CHATHAM GA-INLAND CHATHAM GA-COASTAL JASPER SC-INLAND JASPER SC- 635 PM EDT FRI AUG 15 2025 ...A STRONG THUNDERSTORM WILL IMPACT JASPER AND CHATHAM COUNTIES UNTIL 730 PM EDT... AT 635 PM EDT, DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR BELLINGER HILL AREA, MOVING SOUTHWEST AT 15 MPH. HAZARD...WIND GUSTS UP TO 50 MPH AND PENNY SIZE HAIL. SOURCE...RADAR INDICATED. IMPACT...GUSTY WINDS COULD KNOCK DOWN TREE LIMBS AND BLOW AROUND UNSECURED OBJECTS. MINOR DAMAGE TO OUTDOOR OBJECTS IS POSSIBLE. LOCATIONS IMPACTED INCLUDE... POOLER, BLUFFTON, HUTCHINSON ISLAND, DOWNTOWN SAVANNAH, BELLINGER HILL AREA, SAVANNAH INTERNATIONAL AIRPORT, GODLEY STATION, WILMINGTON ISLAND, GARDEN CITY AND PORT WENTWORTH. — Edit: I got only little. I’ll call it a T.

If Erin reaches cat 4 and sustains it for a couple of days or at least on and off, I think that getting close to 30 total ACE just for Erin would be attainable. @mitchnick

If Erin reaches cat 4 and sustains it for a couple of days or at least on and off, I think that at least getting close to 30 total ACE would be attainable. Latest from NHC: Hurricane Erin Discussion Number 18 NWS National Hurricane Center Miami FL AL052025 500 PM AST Fri Aug 15 2025 Erin continues to slowly become better organized, with convective banding increasing near the center and a couple of attempts to form an eye. Earlier Air Force Reserve Hurricane Hunter data did not show any increase in winds after the previous advisory, although the central pressure fell to near 993 mb. Satellite intensity estimates are in the 60-75 kt range and are gradually increasing. The initial intensity is held at 65 kt pending the arrival of the next NOAA and Air Force aircraft this evening. The initial motion is 290 to 295 degrees at 15 kt. The subtropical ridge to the north will continue to steer Erin west-northwestward through the weekend, although the motion during the next 36 h or so may be closer to 285 degrees. After that time, encroaching mid-latitude westerly flow is forecast to cause a weakness to develop in the ridge, and this will cause Erin to gradually turn northward with a decrease in forward speed. The guidance remains in fairly good agreement through about 72 hours. After that time, there are still differences in both the forward speed and cross-track spread with regards the turn toward the north. The regional hurricane models again lie along the western edge of the guidance envelope, while the GFS remains on the eastern edge. Overall, though, there again has been little change in the guidance envelope and the new forecast track has only minor adjustments from the previous track. Erin is forecast to be in an environment of light to occasionally moderate northwesterly vertical shear and over sea surface temperatures that warm to 29-30C along the forecast track. However, there is also a large area of mid-level dry and African dust to the north of the hurricane, and the satellite appearance suggests Erin is ingesting tongues of dry air. Although the environment may not be ideal, the regional hurricane models are in excellent agreement that Erin will reach a peak intensity at or above 120 kt during the next 2-4 days. Based on this, the new intensity forecast now calls for a peak intensity of 125 kt in 72 h, and it is possible Erin could get stronger than this. As the hurricane gets stronger, there is a high chance that eyewall replacement cycles will cause fluctuations in intensity that are not included in the current forecast. It is also expected that Erin will become very large and powerful hurricane by the end of the forecast period in the southwestern Atlantic, and the current forecast wind radii at 96-120 h may not be large enough. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 18.9N 57.6W 65 KT 75 MPH 12H 16/0600Z 19.6N 59.9W 75 KT 85 MPH 24H 16/1800Z 20.4N 62.7W 90 KT 105 MPH 36H 17/0600Z 21.2N 65.1W 105 KT 120 MPH 48H 17/1800Z 22.3N 67.1W 115 KT 130 MPH 60H 18/0600Z 23.4N 68.5W 120 KT 140 MPH 72H 18/1800Z 24.8N 69.5W 125 KT 145 MPH 96H 19/1800Z 27.9N 70.6W 120 KT 140 MPH 120H 20/1800Z 32.2N 69.7W 115 KT 130 MPH

Any guesses as to what Erin’s total ACE will be? She’s over 4 now.

Hey snowman, How do you define a “big tropical season”? Thanks.

Regarding the followup to Erin that GEFS remains pretty active with, the 12Z Euro ensemble is much quieter for the same time:

It goes out only to Aug 29th, when it is in phase 5.

Yeah, no change in winds, but the minimum SLP did drop 3 mb to 993 mb.

I count 8 of 30 (27%) of 12Z GFS ensemble members landfalling on the Conus from TX to ME within 8/27-9. GEFS suggests the MJO will most likely then be in phase 5, a rather active phase for Conus though not as active as phases 2 and 8. This is keeping me with a moderate concern for now: But the 12Z Euro like the 0Z has no TC from this. Also, it isn’t on the 12Z CMC. So, we’ll see. I already noted the 12Z UKMET with it.

From Dr. Viterito via JB 8/14/25: I've been keeping a very close eye on this area, as it has been a geothermal hotspot helping to feed the Kuroshio Current, the Pacific's equivalent to the Gulf Stream. Did you notice at the very end of the video the narrator talks about the fact that geothermal heating enables the major port to be ice-free year round and that the area is used as a submarine base? "The "culprit" here is the submarine activity of the Eastern Volcanic Front off the east coast of Kamchatka." As the map shows, there has been a tremendous amount of underwater seismic activity in this area for the past 30 days. For the record, there have been 1036 seismic events, the vast majority of which are associated with underwater magma displacement. Keep in mind, these magmas can reach temperatures of 400 degrees C! IRIS/Wilber 3, Mx >=3, July 15 - August 14, 2025. The water off the east coast of Kamchatka moves southward vis the Kamchatka current. Here is a map of this: Wikidata The Kamchatka Current then feeds the Kuroshio Current, and in this case, is providing exceptional warmth to the Kuroshio. This is starkly illustrated in today's sea surface temperature map. In this map the source region is clearly the southeast coast of Kamchatka, and we can see that excess warmth being transported by the Kamchatka Current, which then merges with the Kuroshio. By contrast, here is the seismic map for March, 2025. For that month, there were only 17 seismic events: IRIS/Wilber 3, Mx >=3, March 6, 2025 - April 5, 2025. Here is the resultant SST map (April 6, 2026 [sic]): Clearly, the "hot spot" was much weaker when the seismic activity was lower. It can be argued that the Kamchatka source region is responsible for the large temperature anomaly the Kuroshio is currently experiencing. It's about time the climate community starts to recognize the importance of geothermal inputs into the system. ————————— Any comments?

Unlike the 0Z, the 12Z UKMET is back (similar to yesterday’s 12Z that I’m quoting) with a followup AEW to Erin becoming a TD at 162 and nearly to a TS at 168 just N of the Virgin Islands moving WNW. This looks like the same AEW that the 12Z GFS has but is ~500 miles further WNW than the GFS at 168, which is then only near 16N, 58W. This is the AEW causing the commotion in the SE US on the 6Z GEFS during 8/26-30: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 162 HOURS FORECAST POSITION AT T+162 : 18.9N 62.8W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 22.08.2025 168 19.4N 64.7W 1005 33

Per elsewhere Special TWO drops it to 20/20 so looks like it's not going to happen.

The latest raw recon reports are showing SE winds to 43 mph and SSW winds to 32 mph fwiw.