GaWx

So, BoM has +2.5 for ASO. Though anything's possible, I feel that's way warmer than what will verify then and even probably for the peak. The record high ASO back to 1850 is only +2.2 and just about all other models so far haven't been as warm as this BoM. Plus there tends to be a warm bias overall at this time of year. This will be interesting to follow.

Asheville is another good one to analyze since they get so much more snow on average: - 32 of all 74 seasons (43%) since 1949-50 above their 12.7" mean - A whopping 16 of 26 El Niños (62%) above the 12.7" mean vs - Only 8 of 29 La Niña (28%) vs - 8 of 19 neutral (42%) So, going from La Niña to El Niño more than doubles the chance vs the prior winter for a snowy winter at Asheville. 15 seasons since 1949-50 had 20"+: - 7 of 26 El Niño (27%) - 5 of 19 neutral (26%) - 3 of 29 La Niña (10%) So, the chance for a very snowy winter at Asheville nearly triples from prior winter when going from La Niña to El Niño.

Indeed. Macon is another example. Six of the 26 El Niño seasons since 1950 had above the 1.0" mean. Whereas that's only 23% of them, only 13 of all 74 seasons or only 18% of all since 1949-50 have had above the mean. So, the 23% of El Niño seasons is actually higher than the 15% for other seasons (La Niña and neutral, combined). La Niña really brings it down with only 7%. So, going from La Niña to El Niño more than triples the chance at Macon for an above the mean snow for the season. Neutral is similar to El Niño as is the case for Atlanta.

For much of the SE US, most winters are below the mean. Example: Since 1950, only 1/3 of all seasons had above the mean snowfall at Atlanta. In El Niño seasons, 44% had above the mean snowfall. Whereas that is below 50%, it being well above 33% means El Niños are actually somewhat relatively snowy. Neutral are similar. But La Ninas are much less snowy with only ~20% of Atlanta winters above the mean. Example: This map makes it look like El Niño is a hindrance to snow at Florence, but it isn't at all. So, this map is deceptive for the SE US.

Very little rain in this part of the area. The seabreeze held much of it back. I did hear some loud thunder. The hail just outside Savannah in Richmond Hill, GA, is some of the worst hail in the area in many years, if not decades: https://www.wsav.com/weather-news/hail-rains-down-in-portions-of-chatham-county/amp/ Holy hail! The Melbourne area got hit hard with large hail: https://www.clickorlando.com/weather/2023/04/26/snow-way-hail-covers-i-95-in-florida Hail to this extent and size is very rare in both of these areas.

The Atlanta 1.5" April 25th snow and cold was truly amazing. However, the Atlanta based TWC actually got the year wrong. It was 1910 (same year as the noted Chicago snow), not 1920: https://site.extension.uga.edu/climate/2017/04/april-25-1910-snowfall-in-northern-georgia/#:~:text=From This Day in Weather,of the 30s in April. I've read the old Atlanta newspapers from then (on microfiche at public library) and they predicted for 4/25/1910 rain and warmer than the much colder than normal 4/24. Instead, 4/25 was even colder along with the snow. This snow still is much later in spring than any other measurable snow there on record. Chattanooga was in the same boat except they got 4"! Nashville got 1.5".

No, sorry I don't.

Indeed, the globe and its oceans are warmer overall.

Answer: the latest accumulating snowfall on record for much of the TN Valley and nearby. Nashville got 1.5" on 4/25/1910, which is their latest accumulating snow on record by 15 days (back to 1885)! Chattanooga got an amazing 4.1" that day, which is still their latest accumulating snow on record (back to 1879) by a whopping 17 days! Also, one has to go all of the way back to one full month prior to find as heavy a late season snowstorm (3/25/1971). Their high on 4/25/1910 was a mere 39!

To add to what you said, Atlanta had a high on 4/25/1910 of only 39. After March 26th (going back to 1879), they have had highs below 40 only three times: 39 on 4/3/1987, 36 on 4/5/1891, and 39 on 4/25/1910. So, the 4/25/1910 very cold high really stands out in the record books for how late it is. This accumulating snow so late in April could easily be a once in several hundred year event and could even be a once in a thousand year event. Edit: The old Atlanta newspapers that I read (on microfiche at the public library) and copied forecasted rain and warmer temperatures on April 25th, not snow and colder. April 24th was 18 BN (high of 56 and low of 38) and they thought that that was to be the coldest day of the cold snap. So, this was a big surprise even to the meteorologists!

Does anyone know what happened in your area exactly 113 years ago?

Does anyone here know what happened in Atlanta 113 years ago tomorrow (4/25)?

Today's weekly release (covers last week's mean) has the Nino 1+2 anomaly cooler but only barely. It is still a very impressive +2.5 vs +2.7 the prior two weeks. With only one more full April week left to be reported, this all but assures that this will be the warmest pre El Niño April in 1+2 on record back to 1870, assuming the table that shows the monthlies back to 1870 is going to be based on somewhat similar data. There's often a problem with different tables using different data. So, we'll see later. The more important Nino 3.4 rose from +0.1 to +0.3.

The Happy Hour Goofy is BN dominated in the SE throughout the run.

This afternoon is near ideal here! The temperatures are near normal (highs near 80) but with 30s dewpoints, beautiful blue skies, and a gentle breeze. I could take this all year round. This month has had quite a few similar days. Tomorrow looks similar but with more clouds.

Per two regular posters April is headed to ~58, warmest on record. NYC Mays have been colder than 58 six times since 1870 or once every 25 years. That implies ~4% chance. However, the last one was way back in 1967 during a colder climate. Also, each of those six sub 58 Mays followed a BN to NN April as the six preceding Aprils were 46.9-49.6. This all tells me that the true chance for next month being colder than 58 without knowing how May would start is probably <4%. With May progged to start off BN, I'd raise the chance back up some though probably not above 5% considering our warmer climate.

Not since at least 1870 at Central Park. The closest was 1945, when May was only 3.6 warmer followed by 2005, when May was only 3.8 warmer, and then followed by three that were only 4.6 warmer (2002, 1968, 1915).

Due to how extreme this event was, I feel this is quite possibly not just a 1 in 1,000 year event but also perhaps a once in several thousand year event as Erich Fischer suggests above. However, I also maintain for the reasons I already stated that there's no indication that AGW/CC had much, if anything, to do with the set of freak factors that lead to this. Keep in mind that this occurred over only a small area relatively speaking. Ft Lauderdale is 34 sq mi. I estimate that as much as 35 sq miles had 20+" of rain. And that's probably conservatively high. So, that's 35 sq miles out of 3.5 million sq miles in the entire US. So, there are 100,000 parcels of land the size of Ft Lauderdale in the US. Even though it is obviously a huge deal wherever it occurs, a 1 in several thousand year event occurring over 1/100000 of the US isn't hard to fathom. For that matter, the expectation is that on average several of these 1 in several thousand year events would occur somewhere in the US each year. Whereas I believe that events such as the extreme rains from Hurricane Harvey (covered a much larger area) for example, were made more probable due to AGW, I see no evidence of that for this event for the reasons I stated in my earlier post. But there are certain folks that do their best to blame AGW/CC for as many extreme events as possible even without ample evidence. Imho, that actually leads to more folks denying the existence of AGW.

An extremely dry airmass over N FL: Per KJAX: FAIR SKIES AND A NEAR RECORD DRY AIR MASS FOR MID-APRIL REMAIN ENTRENCHED OVER OUR AREA, WITH OUR MORNING SOUNDING AT JACKSONVILLE ONLY REGISTERING 0.24 INCHES OF PWAT (RECORD FOR 12Z ON APRIL 18 IS 0.20 INCHES). This along with other great radiational cooling parameters allowed lows for a number of major stations to get all of the way down into the low 40s, including Hogtown and Jacksonville at 42. All of the way down in north-central FL at Brooksville it was down to 43. That's only 50 miles NNE of Tampa. Currently the dewpoint is a mere 28 at Ocala with only 17% RH!

More on this huge Ft Lauderdale rain: - Records go back to 1913. - 25.91", which fell mainly within just a 12 hour period, far exceeds the greatest there on record in one calendar day. The old record was 14.59" on 4/25/1979 from a weak low in the NE GOM. Here are prior 10"+ 2 calendar day rains: - 16.74" 10/19-20/1924 from hurricane moving NE from NW Caribb. - 15.79" 4/24-5/1979 from weak NE GOM low - 13.72" 6/2-3/1930 with no tropical system anywhere nearby - 13.10" 10/11-12/1947 from hurricane moving NE from NW Caribb. - 12.25" 10/31-11/1/1969 near stationary front - 11.00" 10/4-5/1948 from hurricane moving NE from NW Caribb. - 10.89" 5/27-28/2003 (nothing tropical). - 10.75" 3/14-15/1919 (nothing tropical). - 10.68" 11/19-20/1973 (nothing tropical). - 10.14" 6/7-8/1999 (nothing tropical). The THREE day record is "only" 18.24" set 10/19-21/1924 per this: https://www.newsweek.com/fort-lauderdale-third-annual-rainfall-only-7-hours-1794169?amp=1 Interestingly, no 10"+ event has occurred from a tropical cyclone since way back in 1948! If someone had told me before I did this research that it had been 75 years since the last from a TC, I would have wondered if that was accurate. Is there any clearcut evidence that GW was a major factor? No clearcut evidence imho. Why? - It occurred with dewpoints in the low 70s and offshore SSTs no higher than the low 80s. Yes, those are above average for mid April. However, SSTs get into the mid to upper 80s and dewpoints into the upper 70s every summer and yet nothing even close to this heavy an event has occurred most years in S FL summers. - Look at the decades for the listed 11 heaviest Ft Lauderdale events since 1913: 1910s, 1920s, 1930s, 1940s (2), 1960s, 1970s (2), 1990s, 2000s, 2020s This looks like a pretty even distribution. If these records had been heavily influenced by the 3 or so degree F warmer globe, I would have expected a heavier concentration since the 1980s (and especially in summer/early fall). Yet, there have been only 3 of 11 since then.

The ONI peak has risen 3.0+ only once on record over the last 173 years from one fall/winter to the next and that was the 3.1 from 1971-2 to 1972-3. In order to get a super Nino in 2023-4, a rise of 3.0 would be needed. Based on this along with perceived warm ENSO model bias this time of year, whereas the chance isn't zero, I believe the odds are low. Like @snowman19 I favor strong (+1.5 to +1.9) right now with a chance of as weak as high end moderate and just a small chance at super.

Note that he said "perhaps the strongest ever in late summer" as opposed to saying "likely" or even just "good chance". "Perhaps" probably means fairly low chance. So, he's not actually predicting the strongest late summer 3.4 anomaly (warmer than +1.9 for JAS). But by saying that, he's sort of covering himself for that low possibility just in case based on the models. With several models being in the high 1's by late summer, saying "perhaps" strongest ever by late summer isn't far fetched imho. Personally, I'm leaning a fair bit lower than that (probably no warmer than mid +1 range) for that early based on perceived warm model bias.

Details mainly for entertainment due to it being a cold outlier: The 12Z Euro is its coldest run yet in the SE for early next week and is significantly colder than the 12Z GFS (both meaning it is likely too cold) with 0C 850s getting just about down to here and a low of 39 at ATL on 4/24 along with several inches of upslope snow in the mountains along the TN/NC border this weekend into early next week. Despite it likely being too cold, a BN pattern would be supported for then especially by a preceding sub -3 AO (lowest since December) and MJO phase 1. A dropping NAO probably helps, too, although by April correlations of -NAO to cold in the deep SE on average drop significantly vs March per charts. Even after then, the GEFS has a pretty strong +PNA for at least a few days very late this month. That could allow for still another cool/mild (BN and low dewpoints) shot of Canadian air then.

Early to mid next week is looking pleasantly cool at night and mild during the afternoons with very low RH. The AO is progged to go below -3 4/19-20, the lowest since December. Also, late next week the PNA is forecasted to get to its highest level since January. Today and tomorrow are looking to be similarly pleasant. Edit: The forecasted MJO phase 1 (and possibly 2 soon after) favors BN in the SE in April.

Doesn't he mean strongest 3.4 on record for the late summer, itself? I see almost no chance for strongest on record 3.4 by late summer. That would be well into the +2 range: +2.6 per 2015-6 and +2.9 per 1877-8. The strongest on record in JAS, alone, is +1.9. The model consensus is no warmer than the high +1 area by JAS and that's ignoring what I think is a warm bias.