GaWx

GFS runs since 7/31 with hurricane: 3 of last 4 -7/31 12Z: hit SC 8/16 -8/3 6Z: hit MX/TX border 8/16 -8/6 0Z: MDR 8/18-21 -8/9 18Z: just off SC 8/25 -8/11 0Z: GOM just off LA 8/26 -8/13 0Z: GOM 8/26-8 -8/13 6Z: GOM 8/25-6 that hits MS 8/26-7. -8/13 18Z: GOM 8/25 hits S TX 8/26

- The stronger August JMA run is following the recent overall model consensus being stronger in 3.4. - It rose sharply to ~+2.2 for both OND and NDJ compared to a +1.76 peak for OND in last month's run. The run from two months ago was at +1.87. - The significance of the JMA being this warm is that unlike a number of models it has generally averaged slightly too cool on the order of 0.1 in nearby runs to 0.3 several months out. - Thus this along with the latest CFS, Euro, Meteo-France, and BoM all being pretty safely in super territory tells me that the chance for a super strong ONI peak has risen sharply (though I still feel that BoM is too warm). I haven't seen the new UKMET nor CANSIPS yet. July UKMET/CANSIPS peaked at +1.82/+1.61. -Based on this along with recent actual warming and a sharp SOI drop, I feel that the chance for a super ONI peak has risen sharply from slight to 50%. The main things holding me from raising it even more are that raising it to just 50% is quite a rise and the OHC fell sharply from +1.30 in mid June to +0.75 in late July. However, OHC looks to be warming now and I do expect significant warming over the next few months. - Nino 1+2 is also significantly warmer this month on the JMA for Dec with ~+2.4 vs ~+1.7 last month. - Nino 3, Nino 4, and IOD all also rose significantly.

On the 12Z EPS through 240, I counted 15 Hs (30% of members) at a minimum from just the wave now in the E MDR. There's something like 30 members from all of the waves, combined, with a H. There still are four different possibilities to watch during the next ten days.

Similar to the 12Z UKMET, the 12Z Euro has a recurving TS well out in the MDR, which appears to be from the subsequent AEW to emerge from Africa in a few days rather than the one west of there.

The 12Z GEFS has 6 hurricanes out of 31 members in the GOM or NW Caribbean on Aug 25th. Keep this in mind:

For the first time recently, the UKMET has Atlantic TCG (favoring recurving from the MDR): NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 138 HOURS FORECAST POSITION AT T+138 : 16.7N 42.6W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 19.08.2023 144 16.8N 42.7W 1009 29 0000UTC 20.08.2023 156 17.1N 43.1W 1008 31 1200UTC 20.08.2023 168 17.8N 43.8W 1007 33

It does look like the OHC plunge has ended and is starting to rebound per the following, which is consistent with your animation's warming west of 140W. I'm expecting mainly net warming the next few months:

1. I agree about the CFS run and the near term SAL. 2. Nevertheless, it is just one CFS run that inactive recently and it is an inferior model. 3. This map of SAL is for only for three days from now. SAL tends to decline rather rapidly past mid August. We'll see. Much of the EPS activity occurs well after the time of this map. Also, the TCGs of the last four GFS runs with TCG occur 9-10 days after this map, a near eternity during this period that ramps up rapidly climowise. I'm currently favoring the last week or so of August to be active with 2 TCGs just during that period a good possibility. Edit: 4. I have for the entire season felt that the hyper forecasts for 2023 are well overdone. Just look at my 2023 season forecast contest entry to see what I was thinking at the start. But that doesn't mean I think it will remain dead the rest of this month like was the case in 2022. Obviously I don't think that as per my recent posts. I think 2-3 TCGs this month, mainly during or just before the last week. That would be nothing like the zero TCGs of last August.

1. Today's 0Z CFS develops only 1 of the 4 possibilities now being watched. 2. Today's 0Z EPS while still quite active isn't quite as active as yesterday's 12Z with the AEW now in the E MDR. And it is still much more active than those from the same time last year. Like night and day. 3. Today's 6Z GFS is the 7th since 7/31 with a H, this one appearing to form from a southern extension of the wave now in the E MDR. Thus it looks to me like at least the 4th GFS run with a H from this AEW. Also, today's 0Z and 6Z GFS are the first consecutive runs since 7/31 with a H. Prior to this, the closest that two GFS runs since 7/31 had a H was five runs apart: -7/31 12Z: hit SC 8/16 -8/3 6Z: hit MX/TX border 8/16 -8/6 0Z: MDR 8/18-21 -8/9 18Z: just off SC 8/25 -8/11 0Z: just off LA 8/26 -8/13 0Z: GOM 8/26-8 -8/13 6Z: GOM 8/25-6 that hits MS 8/26-7

The 0Z GFS has a H in the GOM 8/26-8 moving slowly W. That makes 6 GFS runs out of 53 (11%) since 7/31 with a H on the run: -7/31 12Z: hit SC 8/16 -8/3 6Z: hit MX/TX border 8/16 -8/6 0Z: MDR 8/18-21 -8/9 18Z: just off SC 8/25 -8/11 0Z: just off LA 8/26 -8/13 0Z: GOM 8/26-8 The last three on this list are all from the AEW now in the E Atlantic, the same one the EPS has been harping on since August 4th.

The 18Z GEFS is very active in/near the SE US 8/23-8 largely due to the E Atlantic AEW. Based on the ensemble consensus, I'm thinking 2-3 TCG Aug 18-31 with a lean toward 3. Shutout chances low imo. The EPS a year ago was very quiet...like night and day!

This is about as active as it gets on the 12Z EPS with 4 different waves having a good # of members with TCG: 1) the AEW now near or just off Africa that has resulted in the strongest activity for many days going back to Aug 4th with some members threatening the CONUS 8/23+ 2) some members have TCG in the GOM ahead of the aforementioned AEW 8/19-20 with 5+ TS and 1 H 3) & 4) each of the 2 AEWs following the #1 AEW, one coming off 8/16 largely recurving early and one coming off 8/20 with most still moving westward at 240

The 12Z CMC is developing the wave about to come off/the one the EPS has been harping on to possibly threaten the CONUS 8/23-7. The 12Z Euro has this as a weak but possibly dangerous to Gulf Caribbean Cruiser.

Please elaborate on the connection of CC and the terrible Maui fires. I'm asking because I posted a detailed write-up about the causes in the relevant tropical thread (with NWS sources cited) and didn't realize CC was assumed to be a contributing factor:

1. Indeed, the 0Z GFS has a H south of LA on 8/26. That makes 5 GFS runs out of 45 (1 in 9) since 7/31 with a H on the run: -7/31 12Z: hit SC 8/16 -8/3 6Z: hit MX/TX border 8/16 -8/6 0Z: MDR 8/18-21 -8/9 18Z: just off SC 8/25 -8/11 0Z: just off LA 8/26 2. At 240, the 0Z EPS is once again quite active with that lead wave.

The new 0Z Euro has the active EPS system as a strengthening 1005 mb low just S of PR moving WNW at 240 and has very little for the followup wave that recurved on the 12Z.

Per the 12Z EPS and earlier runs, the key wave appears to me to be what produces the weak low on this map from yesterday's 0Z Euro that is near 15N, 58W at 240 and not the wave behind it that produces the depicted mid MDR 1006 mb low, which is the same low the 12Z Euro recurves. The 12Z EPS has a whopping 8 hurricanes out of the 51 members from the earlier wave, which is about as active as any EPS run in quite awhile. I think I can trace this to some extent all the way back to the 0Z Aug 4th EPS run. This wave is to come off Africa over this weekend, which is ahead of the AEW that leads to the aforementioned recurving 12Z Euro low.

The 100 & 101F SST measured at the buoy in Manatee Bay, FL, made the headlines in the typical sensationalized manner. They appear to have been true readings, but they weren't at all comparable to ocean buoy SSTs. Rather, they were measured in a very shallow and sheltered bay barely off land with the sunlight absorbing dark muddy bottom quite visible. They were measured in the equivalent of a large/deep mud puddle. There are likely numerous very small bodies of water that get that hot or hotter every year that aren't measured. It had 10F 24 hour ranges and it plunged to 84 2 1/2 days later. Even Dr Masters said this isn't a legitimate SST. Other buoys nearby were in the upper 90s, which also weren't legit. But what was/is legit is the Key West buoy's 92+F's hottest, which is itself breaking records.

Indeed. During winter, that study suggests a cooling effect from the volcano in places like Australia, Scandinavia, Korea, and the SE US especially years 3-7. Some of this is likely due to a favoring of El Niño and much of the cooling appears to correlate with increased clouds/precip if I recall correctly.

A devastating wildfire the night of August 8-9 (Tue night) destroyed the city of Lahaina on the west coast of Maui and has killed at least 36 folks. This is a result of a combination of plentiful vegetation (fuel) from a wet winter, it now being dry season, current D1 moderate drought/drier than normal ground due to recent below normal rainfall, low relative humidity, and unusually strong E to NE winds blowing from off the mountains resulting from the strong pressure gradient between major hurricane Dora passing 700 miles SSW of Honolulu, and high pressure to the north. From the following link to the 7/14/23 Drought Information Statement": "Maui County Reports from central Maui indicated that pasture conditions were poor from Kihei to Kaupo. Dry vegetation conditions have also resulted in brush fires in West Maui over the past month in the Olowalu and Kapalua areas. These fires briefly closed Honoapiilani Highway." and "The risk of fires during this year's dry season is elevated due to the abundance of fuels produced by the wet winter and spring, combined with the expectation of below average dry season rainfall." https://www.weather.gov/hfo/DGT Here was the NWS forecast issued Tue afternoon; MAUI LEEWARD WEST- INCLUDING LAHAINA, KAANAPALI 339 PM HST TUE AUG 8 2023 ..HIGH WIND WARNING IN EFFECT UNTIL 6 AM HST WEDNESDAY TONIGHT PARTLY CLOUDY. VERY WINDY. LOWS 69 TO 74. NORTHEAST WINDS 35 TO 45 MPH. GUSTS UP TO 65 MPH IN THE EVENING. A red flag warning had been in effect: URGENT - FIRE WEATHER MESSAGE NATIONAL WEATHER SERVICE HONOLULU HI 317 AM HST TUE AUG 8 2023 ...RED FLAG WARNING FOR LEEWARD AREAS DUE TO STRONG WINDS AND LOW HUMIDITY... .VERY DRY FUELS COMBINED WITH STRONG AND GUSTY EASTERLY WINDS AND LOW HUMIDITIES WILL PRODUCE CRITICAL FIRE WEATHER CONDITIONS THROUGH TONIGHT. ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 6 AM HST WEDNESDAY FOR STRONG WINDS AND LOW HUMIDITY... * AFFECTED AREA...LEEWARD PORTIONS OF ALL HAWAIIAN ISLANDS. * WIND...EAST WINDS 30 TO 45 MPH WITH GUSTS TO AROUND 60 MPH. * HUMIDITY...35 TO 45 PERCENT THROUGH THE AFTERNOON HOURS. * IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY. OUTDOOR BURNING IS NOT RECOMMENDED. NWS discussion just before fire got bad: AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 821 PM HST TUE AUG 8 2023 SYNOPSIS A VERY STRONG HIGH PRESSURE SYSTEM REMAINS IN PLACE NORTH OF THE STATE AND HURRICANE DORA CONTINUES TO MOVE WESTWARD, PASSING WELL SOUTH OF THE ISLANDS TONIGHT. THESE TWO PRESSURE SYSTEMS WILL CONTINUE TO PRODUCE VERY STRONG AND DAMAGING WINDS THROUGH THE OVERNIGHT HOURS. THESE STRONG WINDS COUPLED WITH LOW HUMIDITY LEVELS ARE PRODUCING DANGEROUS FIRE WEATHER CONDITIONS THAT WILL LAST THROUGH WEDNESDAY AFTERNOON. EXPECT DECREASING WIND SPEED TRENDS ON WEDNESDAY AND THURSDAY AS BOTH SYSTEMS MOVE WESTWARD AWAY FROM THE STATE. A MORE TYPICAL BREEZY TRADE WIND WEATHER PATTERN RETURNS FROM FRIDAY THROUGH THE WEEKEND WITH MORE MODERATE TRADE WIND SPEEDS IN THE FORECAST. PRELIMINARY LOCAL STORM REPORT...CORRECTED NATIONAL WEATHER SERVICE HONOLULU HI 1049 PM HST TUE AUG 8 2023 .TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON .DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE. ..REMARKS.. 1047 PM WILDFIRE LAHAINA 20.89N 156.67W 08/08/2023 MAUI HI EMERGENCY MNGR CORRECTS PREVIOUS WILDFIRE REPORT FROM LAHAINA REPORT SOURCE TO SHOW EMERGENCY MANAGER. SOME COMMUNITIES IN LAHAINA, MAUI ARE UNDER EVACUATION NOTICE DUE TO NEARBY WILDFIRE.

NS 14-21, H 6-11, MH 2-5 this forecast vs NS 12-17, H 5-9, MH 1-4 prior forecast Normal 14/7/3. So, higher numbers with near to above normal activity vs being centered near normal in the prior forecast. There's an even wider spread for NS/H. They really have quite the wide spread in this making it difficult to end up wrong.

For the 40 GFS runs since July 31st, an unusually low (for this time of year) 10% of them (four runs) have had a hurricane in the Atlantic basin at any point during the 384 hours (all have been within the fantasy range) with the latest run being just the first Happy Hour run with one: -7/31 12Z: hit SC 8/16 -8/3 6Z: hit MX/TX border 8/16 -8/6 0Z: MDR 8/18-21 -8/9 18Z: just off SC 8/25

Looking ahead to the possible effects on US winters 2024-5 through 2028-9 from the January of 2022 Tonga volcano, the chance of a multiyear El Niño MAY be enhanced while the volcano still has influence, especially during 2025-9. Note how the DJF temperature anomaly pattern over the US in figure 7a comes rather close to a typical El Niño, including the cool SE and warm NW. Also, note especially figure 11d, which shows an El Ninolike Pacific SSTa pattern. Maybe this will counteract the chance for the Niña that at least one model run (August CANSIPS) was suggesting to be possible for 2024-5?? "The MiMA simulations confirm the robustness of the SWV-induced wave structure in the Pacific (Fig. 11ef), and they produce tropical surface temperature anomalies consistent with an El Nino-like pattern (Fig. 11a-d). This heating is produced by the zonally asymmetric distribution of SWV in the tropics, and consistent with the increased surface downward longwave flux over the tropical Pacific in WACCM (Fig. 9a). Thus, it is possible that the SWV forcing from the eruption would favor a positive phase of ENSO on a multi-year timescale, but further work is required to confirm this, in particular with a model including fully interactive ocean and cloud feedbacks." https://www.researchgate.net/publication/372889143_Long-term_surface_impact_of_Hunga_Tonga-Hunga_Ha'apai-like_stratospheric_water_vapor_injection

Looking ahead to the possible effects on SE winters 2024-5 through 2028-9 from the January of 2022 Tonga volcano, the chance of a multiyear El Niño MAY be enhanced while the volcano still has influence, especially during 2025-9. Note how the DJF temperature anomaly pattern over the US in figure 7a comes rather close to a typical El Niño, including the cool SE and mild NW. Also, note especially figure 11d, which shows an El Ninolike Pacific SSTa pattern: "The MiMA simulations confirm the robustness of the SWV-induced wave structure in the Pacific (Fig. 11ef), and they produce tropical surface temperature anomalies consistent with an El Nino-like pattern (Fig. 11a-d). This heating is produced by the zonally asymmetric distribution of SWV in the tropics, and consistent with the increased surface downward longwave flux over the tropical Pacific in WACCM (Fig. 9a). Thus, it is possible that the SWV forcing from the eruption would favor a positive phase of ENSO on a multi-year timescale, but further work is required to confirm this, in particular with a model including fully interactive ocean and cloud feedbacks." https://www.researchgate.net/publication/372889143_Long-term_surface_impact_of_Hunga_Tonga-Hunga_Ha'apai-like_stratospheric_water_vapor_injection