GaWx

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

According to your first link, the probability for a multi-year 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 (mild NW and cool SE). 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

The SOI has averaged solidly negative for over three weeks. What's interesting about that is that this has been driven by very high Darwin SLP rather than low Tahiti SLP. As a matter of fact, the three week period ending this Friday August 11th is going to end up having the highest three week averaged Darwin SLP on record by a good margin (records go back to 1991-2 El Niño). Here are the top five highest 21 day averaged Darwin SLPs on record: 1) 7/22-8/11/2023: ~1016.00 mb (exact # TBD on Friday) 2) 7/26-8/15/1997: 1015.83 mb 3) 8/4-8/24/1993: 1015.73 mb (not El Niño) 4) 7/11-31/2015: 1015.65 mb 5) 8/2-8/22/1994: 1015.54 mb

We just got slammed from 7:50PM til 8:20PM with the most severe thunderstorm I've seen this summer. It was severe warned in advance. The wind gusts at the start of it had to be in the 50s mph and the rain rates were torrential. Preliminary amounts were 1.5-2" within just 30 minutes. My street is completely flooded. Lights were out once for a minute or so with some CTG strikes. On the backside the lightning flashes are at ~35/minute! Everything about this storm was classic for a memorable summer thunderstorm. I'm glad I was inside! What Hunter AAF experienced is similar to what I saw: 0755 PM TSTM WND GST HUNTER ARMY AIRFIELD 32.01N 81.13W 08/08/2023 M53 MPH CHATHAM GA ASOS HUNTER ARMY AIRFIELD GUSTED TO 53 MPH.

At Atlanta and in much of the SE, both 2009-10 and 2010-1 had cold and wintry Dec-Jan making for two good winters in a row, overall. But Feb had major differences between the cold/wintry 2010 and the mild 2011 although even it had snow at Atlanta. Strictly in terms of snowfall, Atlanta had more snow in each of 2009-10 (5.3") and 2010-11 (7.1") than any others between 1983-4 and the present. I will note however that although 1987-8 had less (4.2"), that was all sleet meaning the water equivalent of ~8-9" of snow. Regardless of Feb, which is often mild during La Niña in the SE anyway, 2010-1 was one of the, if not the, coldest/wintriest moderate+ La Niñas in decades at Atlanta and much of the SE. That looks like it was Modoki. 1988-9 was another Modoki and was a bit warmer than normal overall, but Feb of 1989 was snowy in much of the SE, especially NC, and produced one deep SE snow (1" even way down here).

Do you happen to have the link to that met's Twitter video? TIA

Regarding 2024-5, Modoki La Niña?

Indeed, it plunged from mid June through most of July per this though it has steadied out since:

In addition to the TAO buoy 5 day averaged images, I follow all 3 daily index changes. However regarding absolutes, the closest of the 3 to ERSST, which ONI is based on, is OISST as CRW has tended to be too warm and CDAS has been too cool. ERSST has recently been slightly cooler than OISST but closer to it than to CDAS. Also, the weekly SST updates use OISST.

Indeed it did. Also, Nino 1+2 warmed even more than to my +3.3 guess to +3.4. Despite OISST catching that 3.4 cooling last week, things appear to now be reversing in a hurry in 3.4. The TAO buoys update today is another significantly warmer day similar to the last few. Also, today is significantly warmer in 3.4 than yesterday on OISST, the warm biased CRW, and the cool biased CDAS. The CDAS warmed a whopping 0.109 since yesterday, which is the strongest CDAS warming in one day in 3.4 since at least March 1st! Also, it exceeded +1.0 for the first time this El Niño. This along with the recent period of stronger -SOI tells me that we may finally have a period of sustained significant warming upcoming for 3.4, which would be the first time in two months.

Followup: 12Z GFS: Caribbean shear picks up Aug 12 and is strong the rest of the run. The 12Z GEFS also increases shear there Aug 12 and it is strong through at least Aug 17th (that's as far as run is out so far). Edit: 12Z GEFS strong Caribbean shear continues for about a week but then decreases to near normal Aug 20-23 while the strong shear zone shifts just to the north of the Greater Antilles. Meanwhile, E US 500 mb ridging takes over on this GEFS run 8/19-8/23, which if it were to verify would potentially open the door to the E US for anything that might be in the W Atlantic then. I hope that would be shortlived if it happens. The run has 4 hurricanes out of 31 members off the SE coast late fwiw.

I stand corrected. I didn't realize that that much shear was being modeled on the recent GFS/Euro runs 8/15-16. Yes, I see the strong westerly shear in the Caribbean that you posted. I need to reassess the model consensus for Caribbean shear from midmonth on.