GaWx

Interesting dichotomy when looking at # of TCs producing H force winds summer/fall somewhere VA north broken down by ENSO : 1956-2023: La Nina: 0 storms out of 23 seasons Neutral: 4 El Nino: 3 1851-1955: La Nina: 12 storms during 24 seasons/9 seasons of the 24 (3 during 1954 and 2 during 1869) Neutral: 5 El Nino: 2 1851-2023: La Nina: 12 storms during 47 seasons/9 seasons of the 24 Neutral: 9 El Nino: 5 So, for the period 1851-1955, somewhere VA north had H winds on average once every other La Nina/during 38% of them but have had none the last 23 La Nina seasons! Also, whereas a portion of VA north during 1851-1955 had H winds on avg once every 5.5 years, that has dropped to only once every 9.5 years 1956-2023. Could climate change be playing a role or are these changes mainly due to other factors including randomness?

CCer, Now that you point it out, I agree with you that the longest stretch was, indeed, 1936-49 (13 years) vs 11 years (2012-23). Good catch. My bad for not catching that. I hope to reply to your overall posts when I get time.

TheCCer, Is the bolded really true? Credit: Chris Kuball for the following Des Moines data from the heart of the Corn Belt ++++++++++++++++ “Out of those top 21 longest stretches of a 100+ Heat Index, only 5 have occurred since 2000. It does not go back to prior to 1936 but there were several other Dust Bowl years prior to 1936 with extreme heat in IA, as well as previous decades with extreme heat. Decade and # of times on the list 30's-1(doesn't include the very hot years 1930-35) 40s-1 50s-2 60s-1 70s-4 80s-5 90s-2 00s-1 10s-3 20s-1. In fact, last year, 2023 getting back up there in the top 21, stopped the longest streak of NOT having a year in the top 21 (11 years from 2012-2023)." The above doesn't suggest an increase in long dangerously high heat index streaks at Des Moines over the last few decades. If anything, there was a peak in the 70s to 80s. So, with regard to the longest 100+ HI streaks at Des Moines, where's the beef?

Another beautiful day, this time with a bonus of a 70% partial solar eclipse. The peak was at 3:08PM. The temp dropped ~2 F from ~2:30PM to 3:15PM (~72 to ~70) under sunny skies with the drop helped by low RH (dewpoints in 40s). The sun didn’t feel nearly as hot as normal this time of year when sunny. The temp has since risen back. Here’s a pic of what it looked like through my eclipse glasses at 3:12PM (I got lucky to be able to get this pic because I had my phone in one hand and my glasses, which I was able to point right at the sun, in another):

The entire weekend was near perfection here. Loved every moment when outdoors!

Latest NMME has a -PDO in Dec (no surprise). I see no reason to not remain firm at least as of now on a -PDO next winter.

You’re welcome. I’d like to make one more clarification. I wasn’t trying to say they’ve ended up too bullish on average with their April forecasts overall as they, indeed, have actually averaged too bearish with them overall. It is only when they’ve been their most bullish in April that they’ve averaged too bullish. For example, I’ll look at their 29 April # of NS forecasts. Although their five most bullish April forecasts ended up 2.8 too high on average, the 29 April forecasts (which include those five very bullish forecasts) actually ended up 2.7 too low on average! Interesting dichotomy of sorts.

In bold for seven categories I’m referring to where the respective seasons ended up on average vs the 3-6 seasons’ most active CSU April forecasts for each category. There’s lots of overlap from category to category, which is intuitive, though they’re not necessarily all the same years from category to category. To clarify in case anyone is wondering, I do not think CSU is trying to sensationalize as I respect them for their objectivity, knowledge, analytical abilities, and clear communication showing how they get their numbers. I still think the season will be very active even if this April CSU forecast ends up being a bit too bullish.

There is good reason to hope that this April CSU forecast is going to end up too high based on past very active April CSU predictions. They’ve been making April predictions since 1995. I see a pretty clear pattern when they’ve gone very active in April: 1. # NS: They’re predicting 23. Prior to this the highest they predicted in April was 17-19 (five times). Four of those five progs ended up too high. For those 5, they averaged 2.8 too high. 2. NS days: They’re predicting 115. Prior to this the highest they predicted in April was 85-95 (four times). All four of those progs ended up too high. The highest actual of these four was only 58 and they averaged a whopping 40.5 too high! 3. # H: They’re predicting 11. The prior highest predicted in April was 9 (six times). All of those 6 progs ended up too high by an average of 3. 4. H days: They’re predicting 45. The prior highest progs in April were 40-45 (five times). Of these five, four progs came in too high. The five averaged a whopping 19 too high! 5. # MH: They’re predicting 5, which they’ve predicted three other times in April. All three of those progs came in too high by an average of 2.33. 6. MH days: They’re predicting 13, which is tied for the highest ever predicted in April. They’ve progged 10-13 five times. Of those five, three progs were too high. The five averaged 3.25 too high. 7. ACE: They’re predicting 210. The prior highest April progs were 160-183 (five times). Of these five, all progs ended up too high with even the closest being 34 too high! The five averaged a whopping 85.8 too high! Conclusion: If I were a betting man, I’d short CSU’s April ‘24’s forecast overall, especially NS Days, # H, and ACE.

Charlie, 1) This chart was posted by Chris in his thread on the Midwest warming hole: note the reduced warming or even slight cooling in much of the MW during summer vs most other areas. This is despite large increases in crop sizes. 2) From Midwest pro meteorologist Mike Maguire: “On the albedo of global greening absorbing more sunshine and warming the planet. I can debunk that myth quickly. We know that the MOST warming is taking place in the coldest places and at the coldest times (higher latitudes during the Winter and at night). Those are also the times when albedo from the sun has the LEAST impact.” “The nights (with no sun) have been warming the most, days the least. Also, the driest locations with the lowest humidity are warming the most. This is because of the radiation physics of CO2 and H2O and not albedo. In areas with the highest water vapor content, water vapor crowds out much of the CO2 absorption from the same bands of absorption. Some of the radiation absorption bands are already saturated from H2O in areas with very high dew points. In drier areas........which includes ALL cold places, CO2 is able to absorb more long wave radiation because of the absence of H2O absorbing at the same bands. There's no disputing this proven law of radiation physics!”

It has been ~tied w/‘22 & ‘23 since ~Mar 23rd.

Starting yesterday, absolutely awesome wx from my perspective. This will continue through the weekend.

This reminds me of an important point, the CO2 fertilization effect. Increased atmospheric CO2 increases plant growth due to increased photosynthesis. Also, warmer higher latitudes can lead to an increase in vegetation at higher latitudes due to a longer growing season. This increased plant growth has increased the net greenness of the earth over the last few decades (see image below). That includes much of the US Midwest, which has lead to a cool down there in summer: “Carbon dioxide is not only a pollutant but a fertilizer — a key ingredient in photosynthesis that helps plants grow. Some farmers inject CO2 into their greenhouses to accelerate plant growth. But now we’re fertilizing plants on a global scale: In the last two centuries, NASA reports, humans have increased the CO2 content in the air by roughly 50 percent. All that extra CO2 is accelerating leaf growth, and satellites can see it.” The above writeup and the image below are from here: https://www.vox.com/down-to-earth/2024/2/7/24057308/earth-global-greening-climate-change-carbon So, this is a natural negative feedback to AGW. Between the cooling due to increased greenness blocking the sunlight as well as holding soil moisture better and an increase in the amount of CO2 being absorbed due to increased vegetation, there is an increase in uncertainty as to how much the globe will actually end up warming in total. Could it eventually cause an equilibrium and halt GW at some point? Is this negative feedback being properly modeled? Furthermore, the increase in crop sizes has been resulting in an increase in food supply. So, although I’m not trying to minimize the negative effects of increased CO2, I’m saying the effects of increased CO2 are not all bad and thus the good effects should be included in any discussion to give a more honest assessment of the effects of increased CO2. Bad effects include: - worse/more frequent land heat waves, which increases deaths from excess heat - increased sea level due to melting land ice leading to increased coastal inundation - increased energy usage for AC - increased marine heatwaves/coral bleaching - increased frequency/intensity of flooding events due to increased atmospheric moisture content that can be held by warmer air - increased/stronger hurricanes due to warmer oceans - increased flooding from hurricanes due to slower average movement speed due to slower average steering Good effects include: - increased food supply due to CO2 fertilizer effect - less frequent/intense cold waves. There’s evidence that extreme cold has killed more people than extreme heat. Thus, more lives may be saved when netting out decreased cold related deaths vs increased heat related deaths: https://www.forbes.com/sites/joshuacohen/2023/07/19/excessive-summer-heat-can-kill-but-extreme-cold-causes-more-fatalities/amp/ - decreased energy usage for heating. Current US natural gas storage is near record high levels for late March due largely to the warm winter. In summary, increased CO2 has many very detrimental effects. However, there are some beneficial effects that should also be acknowledged in an honest assessment even if we assume that CO2 increases are more harmful than beneficial. Also, is it possible that negative feedbacks due to increased vegetation eventually will halt GW and can climate models accurately account for this?

Hopefully for the US 2024 will end up like 2010, one of their analogs. That year there were zero H hits and only 2 TS hits (one on the low end) on the lower 48.

Today’s NAO is -2.00, which is the most negative of any day Feb 15th through April 7th for the years 1950-present. The old record for that period was -1.84. Also, there have been record daily -NAOs the last five days: https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.gefs.z500.120days.csv

Today’s NAO is -2.00, which is the most negative of any day Feb 15th through April 7th for the years 1950-present. The old record for that period was -1.84. Also, there have been record daily -NAOs the last five days: https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.gefs.z500.120days.csv

The Conyers, GA, tornado was rated as EF-2. Fortunately no more than a couple of minor injuries were a result: "An EF-2 tornado with maximum winds of 115 mph traveled ENE 9.5 miles across Rockdale County, including the city of Conyers, downing hundreds of trees, many on homes, cars and businesses. Two injuries were reported.”

So far it has been a warm spring averaged out. April will likely end up warmer than normal, too. These intermittent cooldowns can’t keep up with the warm periods.

This very strong -NAO has included record daily strong -NAOs Mar 31 through today with another record for the date expected tomorrow. Tomorrow’s is being forecasted by GEFS to be the strongest -NAO daily of this stretch. Daily records go back to 1950.

And this -NAO has consisted of record daily strong -NAOs Mar 31 through today with another record for the date expected tomorrow. Daily records go back to 1950.

That Conyers tornado looked very scary on the radar with a clearcut circulation. Hopefully nobody got hurt and the damage wasn’t too bad. ———— “There have been 71 recorded wind events in Conyers. The most severe event was an F2 tornado, which occurred in 1973. Spotlight: An F2 Tornado Damages: $275,000,000 Date: Mar 31, 1973” https://riskfactor.com/city/conyers-ga/1319336_fsid/wind

They’ve just increased the tornado threat level somewhat for tomorrow for E NC/far SE VA/far NE SC from 2-5% to 5-10%.

Eastern AL/western GA overnight... In response to the amplifying midlevel trough/deepening cyclone over the MS/OH Valleys, deep-layer flow and low-level moisture advection will increase tonight across AL/GA. A surge of upper 60s boundary-layer dewpoints and strengthening low-level shear both appear supportive of supercells/tornadoes overnight in a broken band ahead of the synoptic cold front. An isolated strong tornado or two will be possible. https://www.spc.noaa.gov/products/outlook/day1otlk.html

Regarding just GA/NC/SC/FL: Look out for potential tornadoes tonight in much of GA, especially W portion, as well as in the W portions of NC/SC/N FL. The overall threat is higher than it appeared on Sunday when I last posted about this. Eastern AL/western GA overnight... In response to the amplifying midlevel trough/deepening cyclone over the MS/OH Valleys, deep-layer flow and low-level moisture advection will increase tonight across AL/GA. A surge of upper 60s boundary-layer dewpoints and strengthening low-level shear both appear supportive of supercells/tornadoes overnight in a broken band ahead of the synoptic cold front. An isolated strong tornado or two will be possible. https://www.spc.noaa.gov/products/outlook/day1otlk.html

In GA, new record high minimums will likely be set for April 2nd in Atlanta, Athens, Rome, Gainesville, Macon, and Valdosta among other locations. Among the official obs in GA, all lows as of this morning were 61-68. The warmest was at Peachtree City, which is often one of the cooler cities. In SC/NC Greenville, Charlotte, Asheville, Raleigh, and Fayetteville among others look to set new record high lows while Columbia looks to tie. If Asheville’s 63 holds, it would be the warmest low so early in the season.