cbmclean

39 minutes ago, NorthHillsWx said:

Another underperformer in Raleigh, though we’re at 0.68” including yesterday’s shower. Good rain but was pretty certain we’d get at least an inch given forecasts and models. MTD 0.82” which equals our entire month of April rainfall here. It’s still raining a little so these are not final totals 

Blame the gravity waves.

RAH AFD mentioning the possibility of losing QPF due to a "gravity wave".  Wikipedia essentially describes a gravity wave as any wave where gravity is the restorative force, which describes a lot of waves.  There is a section on atmospheric examples but it's very broad.  Anyone care to share on what gravity wave means in the context of NC weather?

Waves of moderate showers and storms will continue to be
directed across the Carolina Wed evening into Thurs morning
ahead of a back-door cold frontal passage slowly sagging south
across the southern Mid-Atlantic. Precip chances may be
negatively impacted by any gravity wave development during this
time, which can rapidly erode precip generation in this type of
pattern. By Thurs morning, the combination of frontogentical
forcing and an area of low pressure rippling along the front
will likely bring another round of widespread showers and
isolated storms before shifting east of the area by late Thurs
evening. Uncertainty in timing of the fropa is resulting in
lower confidence in the development of an unstable air mass
supportive of surface-based convection Thurs afternoon, which
will be needed to realize any severe potential. Strong and
increasing shear with height will be highly favorable for storm
organization, but conditional on development of deep convection
first.

Storm total rainfall through Thurs evening looks to bring much
needed rain to the area with the reasonable low-end from the
HREF still producing a swath of 0.75 to 1" somewhere over the
Carolinas. However, the experimental REFS paints a troubling
alternate scenario with reasonable low-end amounts closer 0.25
to 0.5". With the potential for gravity wave development and
more quickly eroding shields of precipitation, this scenario
can`t be ruled out.

8 hours ago, WxUSAF said:

But we can actually measure and quantify this and see that’s not true?

What is "truth"?  And did you really mean to phrase that as a question.

0.43" for the day.  1.32" for the week.  1.53" since last Saturday.  Together with reduced evaporation from cool temps, the bleeding is stopped...for now.

0.55 last night.  1.10 for the week.

0.17".  At least enough to lay the pollen for a bit.

Didn't think I was going to need long pants anymore until the fall, but here we are.  Currently 56.1 F, which is also the daily low (so far).  Blustery as well.

0.18".

28.6 for a low last night.  Last hard freeze of the season?

19 minutes ago, Stormchaserchuck1 said:

Early signs are El Nino is developing as east-based

 

Crap.

11 hours ago, Stormchaserchuck1 said:

Sorry to dwell on the Winter West Coast ridge again, but this really stands out to me as an extreme anomaly

Most extreme West Coast DJF ridge analogs

The news is, the ridge really sticks around +time in analog cases.. this is the following year:

March (not included in my visual analog picks.. yet almost as strong of an anomaly!)

April (+60dm over the SW, US is extreme!)

May

Summer (June-August)

Following Winter (26-27 analog)

^75% of the N. Hemisphere is +H5 in the following Winter, which fits a warming sequence possibly associated with El Nino. The main point is just the skew warm-general +time. 

This is the mid-latitudes the following Winter (26-27 analog)

Winter PNA DJF 25-26 was negative, so interesting that they got a #1 record warm Winter on the West coast. Monthly PNA:

-1.41
2026   0.79  -0.56

How is it possible for there to be a -PNA with that much of a western ridge?  What exactly is the definition of the PNA index?

3 hours ago, GaWx said:

 Even if RONI ends up peaking +1.5+, the DC area could still have a BN averaged winter based on the 2009-10, 1965-6, and 1957-8 analogs. What did these 3 analogs have in common? -NAO and -AO, both of which were lacking in nearly all of the other +1.5+ ENSO winters. It wasn’t the Pacific that made the difference as they almost always had +PNA and no -EPO/-WPO for all +1.5+ ENSO.

 So, a -NAO/-AO would appear to be the deciders. The major challenge though for getting a -NAO is going to be sunspots almost for sure still not getting down to low (say, sub 35/month). There hasn’t been even one -NAO winter since 1980 with a >35 sunspot avg! So, the odds would be heavily against a cold DC area winter should ENSO get to +1.5+. In that case, the best hope would be for a NN instead of mild DC winter. Your better hope for a cold winter would as you’d suspect be for a sub +1.5 RONI peak this fall/winter.

What is the hypothesized physical mechanism of causation between sunspots (or solar cycle in general) and high latitude blocking?

10 minutes ago, wxman said:

You would think that this is the exact type of thing the the AI models would address?  At least where I am the euro AI never really loved the blizzard and while I'm happy with my 16.3" it was not the 2 feet shown on many non-AI models.  In some respects outside the immediate coast up through NYC-BOS the euro AI was closer to reality. 

I had a similar thought about cold chasing moisture, especially east of the Apps and double especially east of the taller Apps down in my neck of the woods.  Every model run in history overestimates how fast the cold gets over the mountains and frequently hallucinates phantom snow as a result.  Since the AIs are trained on historical data one would think that this bias should go poof on an AI model.

56 minutes ago, psuhoffman said:

Not sure this is the right thread but...  something to keep in mind for future miller b storms, almost every single one going back to the 80s, tends to trend west up until about 24-36 hours out, and then shifts east and pulls the rug out at the last minute to some extent.  Some didn't do it to us...like Jan 2015 which did that rug pull to NYC, or Feb 89 that rug pulled me in NJ, but they all do it.  Some recent examples for our area are Dec 2000, Boxing day, March 8, 2018, Feb 1 2021, and this week.  Where around 24-48 hours out things were trending west and we got excited and then at the very end reality set in and the storm ended up just a little northeast.  That is the MO.  That happens ALWAYS every single time.  Expect it.  It just is how the models are with these miller b storms.  I don't know why.  I have just observed they tend to be under amplified and too far east around days 4-7 then over correct and get us excited around day 2-3 and then shift back at the last minute and everything shifts 50-75 miles east the final 24 hours.  

That doesn't mean we can't EVERY get a lot of snow from a miller B, but it's super rare and we want it amplifying well west not relying on getting the very back edge of the developing CCB zone because that will almost always end up further east than guidance shows 2-3 days out.  

I have seen some debate if this was a Miller A or B or hybrid or what (which is not unusual).  I'm beginning to wonder if how useful those categories really are, but I was under the impression that one of the hallmarks of a B was a Ohio Valley low that transfers, and I didn't think that there was one of those in this case.  In your perception, what made this storm more "B-ish"?

1 minute ago, Terpeast said:

Yeah. If the PDO doesn’t take its annual nosedive this summer, we may have a shot at more +pna now that coastal storm tracks seem to be coming back, and we may also get more blocking up top. Couple that with storms (both tropical and midlatitude) getting more intense with more moisture than in the past, we may have an above normal shot at a MECS if the nino doesn’t go ape. I don’t think it will because the WWBs have been struggling and the SOI is still positive, and subsurface is only mildly AN. If this was gonna be a super, we’d already be seeing +6 subsurface with a negative SOI by now. 

Webb seems to be really hyping the strength.  I suspect he would be gleeful with a strong east-based episode.

1 minute ago, fujiwara79 said:

so we currently have a -PNA and +NAO, and yet we have a 970mb low crawling up the coast with blizzard warnings in NYC.  When was the last time something like that happened?

Isn't there going to be a western ridge spike, aka +PNA?

4 minutes ago, bncho said:

he surface deception

Dang Euro with its surface deceptions...

This SE weenie is rooting for you guys!!

OK, honest thermodynamics/atmospheric physics questions that has puzzled me for a long time.  Right now my temp is 60.3 °.  Temps are dropping very slowly.  Sometimes on nights like tonight's the temps completely steady out.  The ground is warm so it radiates energy at a high rate.  To slow (or even stop) the temperature decrease, something must be adding energy, but what is it?  The sky is clear so there is no downwelling radiation from clouds.  There is no wind so there is no warm-air advection or turbulent mixing.  Where is the energy coming from?  Is it radiating from the water vapor in the air?     

Down to 23 F this morning.  Really impressed with the cold hanging on as much as it can. 

I propose consideration to replace all normal water in the biosphere with heavy water (D2O).  Since it freezes at ~38.9 °F we could gain a lot of marginal events.  We'd have to maintain a supply of regular water for drinking since in large quantities heavy water is toxic.  

Some background on AI models.  https://x.com/i/status/2021333729088585882

49 minutes ago, psuhoffman said:

Average highs might be too warm but what is the mean 850 and wet bulb temp?  Again why do you act like we need a cold regime to snow. We have needed that recently but historically we got so many snowstorms in marginal thermal regimes if we get a good storm track. Do you know how many Baltimore snows were 45 the day before and after it snowed. We need those to return. Because cold regimes are often dry!  A big part of our snow climo was from snowstorms in marginal temp regimes not cold ones. One of the reasons we are stuck in the worst snow drought EVER is that for the last 10 years or only snows when it’s cold. We need to get snow when the pattern isn’t perfect or Baltimore is going to continue to average half of what it’s long term 140 year average actually is. 

Do you actually think there is a chance to recover any of that loss?  I fear that ship may have sailed.

This is getting surreal.

3 minutes ago, psuhoffman said:

Because we had a god damn perfect epo/pna pattern. Of course it can still get cold if everything is fucking perfect. We’re talking about losing snow along the margins. losing those snows we used to sneak in when the pattern wasn’t good. 

Next year will be extremely telling.  If a decent central or even west-based El Nino develops, can you guys score with marginal homegrown cold, without crazy EPO blocking?  Are we starting an exit out of the dreg -PDO minimum?  Can we ever have regular bad pattern that isn't a shit the blinds?