GaWx

A pretty strong CAD for the main CAD areas has been shown on some runs of the GFS, including the strongest version yet on the 18Z resulting in a very cold rain with only low to middle 30s during the day Fri 3/1. A few spots even have ZR or IP. The earlier 0Z GFS was similar though not quite as cold. However, the Euro and CMC as well as the 12Z and 6Z GFS don’t have anything like that for Fri. So, the 18Z GFS is very likely too cold with it being such an outlier and thus the worst scenario would probably be just a 40s cold rain.

2017, 20 I showed stats for NYC and especially Boston that suggest a modest correlation likely really does exist in the NE. Keep in mind that any correlation is likely not strong thus meaning a good number of exceptions and also that it is more for the NE US, especially Boston area, and not so much if any for the Mid Atlantic.

More or less. The lowlands from the upper GA coast to CHS (not downtown and nearby in SAV as it fortunately is 20-40 feet up on a bluff) were devastated by storm surge, especially many poor African Americans living on islands. It was the most destructive US natural disaster at the time. Very sad. “Unfortunately, not all communities received the warnings. Home to more than 30,000 African Americans who farmed, worked in rice fields, and plied nearby waters for fish, oysters, shrimp, and crabs, the Sea Islands were accessible only by boat. Their remote location allowed for the preservation of the unique Gullah and Geecheeculture, but limited communication with the mainland—a fact that would carry dire consequences for residents unprepared for the coming storm.” https://www.georgiaencyclopedia.org/articles/history-archaeology/1893-sea-islands-hurricane/

The 1893 Sea Islands hurricane drowned ~2,000 in GA/SC and left ~30K homeless. https://hurricanescience.org/history/storms/pre1900s/1893/

Others in the top 13 from another era, when tropical activity was probably undercounted: #3: 1893, a devastating season for the US #4: 1926, a very bad season for FL/Gulf/Bermuda #8: 1950 FL hard hit #9: 1961 #11: 1887 #12: 1878 Hoping if there is another very active ACE that they mainly stay offshore and not like 1893, 1926, 1950, 2004, 2005, 2017, 2020, etc.

2020 only barely missed the top 10 at #13 just behind 1887 and 1878.

Today’s Euro Weeklies are warmer for 3/11-18 and not as cold 3/18-25 vs yesterday’s run.

Today’s Euro Weeklies are warmer for 3/11-18 and not as cold 3/18-25 vs yesterday’s run.

https://atlas.niu.edu/forecast/aam/cfsv2_aam_fcst_current.png

Consistent with this, much of the SE will end up only 1-2 F AN this DJF. I consider that within the NN range. To compare, 2022-23 was 4-5 AN in the same areas or 3F warmer (270 fewer heating degree days) resulting in a very mild winter.

OHC steep drop continues with it down to -0.2, an indicator of a good chance for La Niña later this year.

GLAAM prediction fwiw from CFS ens: goes slightly negative for next 10 days followed by a rise to weak/moderate positive mid to late March meaning an attempt of one last El Niñoish pattern then?

I agree that being in phase 5 in March isn’t itself a warm signal. We happened to have talked about this same thing earlier today in the SE. I had myself assumed it was similar to met winter and thus had at first assumed phases 4 and 5 had a warm signal. Then I was corrected and I agreed with the correction when I saw what’s below. Looking closely at it, it shows both 4 and 5 averaging near normal for FMA in both the SE and TN Valley fwiw with average anomalies between -0.3C and +0.3C. I say fwiw because as we know the MJO is just one factor even though an important one. These are averages of numerous cases with some BN, some NN, and some AN. Phase 8 is also mainly near normal while 6 and 7 have averaged generally warmer than normal while 1-3 have averaged mainly colder than normal per the same source. I saw that today’s Weeklies start off mild for most days of Mar 1-10 in much of our areas with a transition to cold dominating the 2nd half of Mar. However, I’m taking especially the 2nd half of Mar cold prediction with a huge grain due to recent too cold predictions by all of the models. The Weeklies have strong -AO/-NAO blocking along with a moderate +PNA/Aleutian troughing. The problem though is that the AO and NAO forecasts made just 2 weeks ago for now/late Feb were a huge bust: Also, the +PNA ended much more quickly than forecasted. So, it remains to be seen to say the least whether or not these will verify though it appears that the forecast for -AO and -NAO would probably have a weak SPV to support them.

Indeed. The one exception this winter was in late Dec, when they were still predicting mainly mild for that mid Jan week that was then just over two weeks out and that turned out to be the coldest of the winter. What an odd curve ball that was. Some areas predicted on this map to be +5 for that week ended up -20 instead!

They and all the models, including ensembles only 10 or so days out, were fooled by this non existing strong AO/NAO block predicted for mid-Feb. So, then it looked to me like the Bleaklies, extended GEFS, and the CFS ensemble were going to score a big victory once mid Feb. would arrive since the medium range ensembles all now had this. The GEFS as I posted about still had very strong blocking through the Feb 8 run and then it backed off each day more and more til it vanished. So, I had fallen for it.

For the purpose of making the readers laugh and not to be taken seriously, the Euro Bleaklies have for March a mild first third, a short transition, and then a cold last half due to a combo of +PNA/Aleutian Low and a strong -NAO/-AO. I feel like I’m having deja vu all over again as Yogi Bera would say. Don’t shoot the messenger as I’m just messaging the super important inaccurate Bleaklies. Nothing much else is happening anyway.

Even down in this area, we’re in a wintry precip “drought” of sorts. It has been 6 years, 1.5 months since the last T of wintry precip. Not getting even a T has happened in ~50% of seasons and not getting measurable has happened in ~5/6 of seasons. So, for any one cold season, not getting any isn’t the least bit unusual and getting any measurable is a special treat. But not getting even a T for over 6 years is highly unusual as it hasn’t happened since at least the 1880s-1870s. In the 1920s, there was a 5 years, 11 month drought.

FMA fwiw

Morning lows at KSAV 2/19-21: 33, 34, 36 One last sub 40 in the string likely tonight and then Sun (2/25). Another beautiful, very low dewpoint day with another high in the middle 60s expected today. A great time to be outside with pollen still moderate, no bugs, and near perfect wx!

My bad. I was in DJF mode. In reality, phases 4 and 5 average near normal in the SE for FMA with 6 and 7 the warmest ones averaged out. Coldest averaged out are 1, 2 and 3. But regardless, MJO phase correlations are only moderate:

Today’s MJO forecasts suggest an increased chance for moderate or stronger phases 4 and 5 starting ~March 5. The folks wanting it mild to warm then should be happy about this though the correlation of those phases to warmth isn’t that strong as MJO correlations tend to be moderate. Also although very much a fwiw being how poorly they’ve done, yesterday’s Euro Weeklies are mainly mild Mar 1-10.

It wasn’t just the extended models that failed badly. Failing that far out isn’t at all unusual due to low skill. But look at how badly the GEFS (other models were similar) busted with the very strong -AO predictions made 2/6-8 for 2/13-20: 2/6 predicted -3.5 2/7 predicted -3.0 2/8 predicted -3.2 2/6 AO prediction: -3.5 for 2/13-20 (all days sub -3.0!) Actual AO: -0.6 for 2/13-20 (2/16-20 all ended up above all 30 2/6 prediction’s members!)(2/20 ended up +2 vs -3 progs!) https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.gefs.z1000.120days.csv

I was curious because I had never analyzed this. The following analysis of the top 10 ACE seasons suggests to me that a weak to moderate correlation of ACE to BOS/NYC snowfall the next cold season quite possibly exists, especially BOS, though ACE definitely shouldn’t be weighted heavily: Top 10 ACE years/snowfall following cold season 1933 NYC: 52.0”; BOS: 62.7”; mod La Nina 2005 NYC: 40.0”; BOS: 39.9”; wk La Nina 1893 NYC: 39.2”; BOS: 64.0”; mod La Nina 1926 NYC: 22.3”; BOS: 41.1”; neutral 1995 NYC: 75.6”; BOS: 107.6”; mod La Nina 2004 NYC: 41.0”; BOS: 86.6”; wk El Niño 2017 NYC: 40.9”; BOS: 59.9”; mod La Niña 1950 NYC: 9.3”; BOS: 29.7”; neutral 1961 NYC: 18.1”; BOS: 44.7”; neutral 1998 NYC: 12.7”; BOS: 36.4”; strng La Nina AVG NYC for top 10 ACE: 35.1” vs 28.5” mean of all years since 1868-9 or 23% above mean snowfall 2 MAN (including record heaviest), 4 AN, 0 NN, 2 BN, 2 MBN; 60% of top 10 ACE seasons had above snowfall median to follow —————————————- AVG BOS for top 10 ACE: 57.3” vs 43.1” mean all years since 1890-1 or 33% above mean snowfall 2 MAN (both in top 5), 3 AN, 4 NN, 1 BN, 0 MBN; 70% of top 10 ACE seasons had above snowfall median to follow ———————————— ACE: https://en.m.wikipedia.org/wiki/Accumulated_cyclone_energy#:~:text=Accumulated cyclone energy (ACE) is,into a single index value. NYC: https://www.weather.gov/wrh/Climate?wfo=okx BOS: https://www.weather.gov/wrh/Climate?wfo=box *Edit: This is a small sample but is it possible that a moderate La Niña has a notable correlation to heavier snow in BOS and/or NYC? Anyone know?

The historical data (each year's ACE and each winter's snowfall by EC city) is out there in case someone wanted to see if there's any significant correlation.

This EPO dipped only down to -218 vs the models showing -300: 2024 02 12 -47.15 2024 02 13 -167.32 2024 02 14 -186.38 2024 02 15 -187.46 2024 02 16 -216.35 2024 02 17 -218.04 2024 02 18 -150.94