Christmas Eve/Day Annual Scrooger Event

[CT Rain]

3km NAM has some epic upslope precip for the Poconos and Catskills. Have to worry about some flash flooding there especially with snow melt. 

[powderfreak]

6 minutes ago, OceanStWx said:

Therein lies the problem. PoP from models are created from QPF. The more QPF the higher the PoP (to a certain extent, it's not like you need 5 inches to get 100% PoP). So even if a model is spitting out a lot of 0.01" amounts, that will translate to a low PoP. And if you blend a bunch of models with 0.01" in different locations, the PoP can go even lower. 

So you manually need to increase the values. That's usually the failure point in the forecasts.

It makes sense how it's calculated in the model sense.  A bunch of models showing 0.05"-0.10" over say Connecticut probably should be a different POP than a bunch of models showing that same thing in the Northern Greens and Northern Whites.  In CT relying on synoptic lift, there's still a decent chance that doesn't happen or it's more scattered/spread out... but in the mountains that signal is going to result in precipitation falling from the sky much more often than not.  Maybe its a quarter inch of snow, maybe it's 3-4"... but something will fall.

[Ginx snewx]

1 hour ago, powderfreak said:

Who is John Bagioni? lol.

He posts here. Met FXWX, great guy and excellent Met

[weatherwiz]

I wish there was a stronger signal for convection. Oh well...another 6 weeks to go until our annual February event 

[powderfreak]

This is why we put 100% pops on NW flow?  Like Phin said, quite a distraction from the coming Grinch.

That escalated quickly.  Full dendrites now, the wall of precip developed fast with the nocturnal inversion trying to get going.  Mountain is getting hammered all the sudden.

Did a black and white filter on the cell phone off the back porch.  POPs near 100%, ha.

[Ginx snewx]

Outside climo I would assume is not good

 

[Ginx snewx]

Is this current obs thread or Grinch?

[Ginx snewx]

Anomalously strong low level jet crosses the region Christmas Eve 
night into Christmas morning. Both ensemble systems NAEFS and ECMWF 
have 850 mb and 1000 mb wind anomalies 5+ standard deviations along 
with percentiles MAXED out! In addition, deterministic guidance 
continues to trend upward with low level 925 mb jet up to 75-85 kt 
of wind streaming across CT-RI and eastern MA Thu night into Fri 
morning. While models do struggle with low level lapse rates on 
southerly wind events, model time sections indicate 50-60 kt of wind 
extending downward to below 1 kft! That's typically a good signal 
for 50+ kt reaching the surface. Another rule of thumb, taking 60-
70% of 925 mb (75-85 kt) jet, which still yields 50+ to the surface. 
Furthermore, model guidance advecting dew pts into the mid 50s ahead 
of the front. This low level moisture and warmth will ease the low 
level inversion and increase the wind threat. Even MOS guid for some 
of coastal locations indicating 40+ kt of sustained wind! So in a 
nutshell, ensembles, deterministic guidance and model soundings all 
scream the potential for a high end wind event and residents need to 
prepare for possible power outages Christmas Eve night into 
Christmas morning. This combined with holiday approaching will issue 
a 5th period High Wind Watch for RI and Eastern MA, this includes 
Boston, Providence, Cape Cod and the Islands. After collaboration 
with WFO ALY & OKX will hold off on interior CT given highest threat 
is RI and Eastern MA as low level jet continues to increase as it 
advects across those areas. However later shifts may have to expand 
high wind watch westward into CT. 

[Damage In Tolland]

 

[Ginx snewx]

7 minutes ago, Damage In Tolland said:

 

Wish we were here

[Damage In Tolland]

2 minutes ago, Ginx snewx said:

Wish we were here

Yup . He’s a mean one for sure.Nothing to track or look forward to for weeks 

[Ginx snewx]

4 minutes ago, Damage In Tolland said:

Yup . He’s a mean one for sure.Nothing to track or look forward to for weeks 

6Z Euro 

[CoastalWx]

3 minutes ago, Ginx snewx said:

6Z Euro 

I hope there’s cactus and Joshua trees in Taunton this summer. 

[Ginx snewx]

2 minutes ago, CoastalWx said:

I hope there’s cactus and Joshua trees in Taunton this summer. 

Lol. Drought is such a joke in NE.

[weatherwiz]

I still think it's going to be tough to generate widespread (or region wide 50-60 knot) winds. The core of the LLJ still looks to coincide with the timing of the heaviest rainfall. Not good when looking to draw down big winds. Yes, any inversion looks weak to "non-existent" (I don't totally buy a non-existing inversion in these setups) but you still have to get some mixing going and those llvl lapse rates are a joke. It seems we do better wind wise when they start exceeding 6.5 C/KM...they're pretty meh here. 

[Ginx snewx]

Just now, weatherwiz said:

I still think it's going to be tough to generate widespread (or region wide 50-60 knot) winds. The core of the LLJ still looks to coincide with the timing of the heaviest rainfall. Not good when looking to draw down big winds. Yes, any inversion looks weak to "non-existent" (I don't totally buy a non-existing inversion in these setups) but you still have to get some mixing going and those llvl lapse rates are a joke. It seems we do better wind wise when they start exceeding 6.5 C/KM...they're pretty meh here. 

Models can't handle low level lapse rates in these low top convective situations.  You have downplayed winds pretty much everytime while we end up with power loss and trees in houses. Think out of the box you have put yourself in.

[Great Snow 1717]

LOL

[HIPPYVALLEY]

13 minutes ago, CoastalWx said:

I hope there’s cactus and Joshua trees in Taunton this summer. 

I said yesterday, let’s get all the precipitation out-of-the-way this winter and hope that it doesn’t rain JJA.  Summer delight. 
Plus we’ll get the enjoyment of a few S of Boston posters cryin’ about reservoirs. 

[weatherwiz]

1 minute ago, Ginx snewx said:

Models can't handle low level lapse rates in these low top convective situations.  You have downplayed winds pretty much everytime while we end up with power loss and trees in houses. Think out of the box you have put yourself in.

I've played up the past several wind events..didn't downplay any of them. 

This isn't a low topped convective situation either. Outside of the intense forcing this is very little instability to work with aloft...certainly not enough for any convective elements. And that whole "models can't handle low level lapse rates" thing made zero sense. Low-level lapse rates are going to be garbage...all you have to do is look at the thermal profile in the lowest 10,000 feet.

Torrential rainfall is not going to mix winds down, in fact, torrential rainfall will help to induce an inversion. This is not a big wind setup. Sure...winds at 925 and 850 are off the charts, but that means nothing at the surface is they can't be tapped into. Sustained winds will be the most impressive (20-30 mph) with gusts 40-50 and the typical spots that get above 60 will do so. But this isn't a region wide 60+ gust setup

[Baroclinic Zone]

This is looking like a fun storm.  2-4" of salt-scouring rain and 60mph leaf dropping winds.

[Ginx snewx]

4 minutes ago, weatherwiz said:

I've played up the past several wind events..didn't downplay any of them. 

This isn't a low topped convective situation either. Outside of the intense forcing this is very little instability to work with aloft...certainly not enough for any convective elements. And that whole "models can't handle low level lapse rates" thing made zero sense. Low-level lapse rates are going to be garbage...all you have to do is look at the thermal profile in the lowest 10,000 feet.

Torrential rainfall is not going to mix winds down, in fact, torrential rainfall will help to induce an inversion. This is not a big wind setup. Sure...winds at 925 and 850 are off the charts, but that means nothing at the surface is they can't be tapped into. Sustained winds will be the most impressive (20-30 mph) with gusts 40-50 and the typical spots that get above 60 will do so. But this isn't a region wide 60+ gust setup

Hmmm

The guidance continues to beat the drum on potential for a high end,
potentially damaging wind event. As the parent low generates a
secondary low along the frontal boundary over the mid Atlantic a
very robust low level jet develops that would be unusually strong
for this time of year. We`re talking 75 to 85 kts at 925 mb and 85
to 95 kts at 850 mb. As mentioned by the previous forecaster, the
EPS and NAEFS ensembles continue to depict anomalies of >5 standard
deviations and maxed out percentiles! So, while historically these
southerly wind events struggle to mix down and modeled soundings
would indicate as much, the anomalous warmth that comes with it
should help to break that subtle inversion enough to mix down some
of those wind, and with that magnitude, even 50-60% would cause
scattered downed trees and power outages. Compounding that risk is
the heavy downpours and potential fine line of convection moving
through in the morning that would help to mix down the stronger
gusts

 

n additional concern is with strong to potentially damaging
winds Thursday night into early Friday morning. Models continue
to show 65 to 75 kt winds at 950 mb during this period. The core
of this low level jet is most likely to pass over Long Island
and southeast Connecticut. Forecast soundings indicate an
inversion around or just below these high winds and this is
typically a difficult forecast on how much will mix down to the
surface, but with models continuing to show signs of a potential
squall line or convective cold frontal band, this would enhance
the chances for stronger winds to mix down to the surface. If
this type of rain band/squall line materializes, the winds would
effectively weaken considerably once it passes, similar to what
occurred on November 15. Advisory-criteria winds could occur
for the inland areas. Strongest sustained winds and gusts would
be from late evening Thursday through around daybreak Friday.

[Great Snow 1717]

3 minutes ago, weatherwiz said:

I've played up the past several wind events..didn't downplay any of them. 

This isn't a low topped convective situation either. Outside of the intense forcing this is very little instability to work with aloft...certainly not enough for any convective elements. And that whole "models can't handle low level lapse rates" thing made zero sense. Low-level lapse rates are going to be garbage...all you have to do is look at the thermal profile in the lowest 10,000 feet.

Torrential rainfall is not going to mix winds down, in fact, torrential rainfall will help to induce an inversion. This is not a big wind setup. Sure...winds at 925 and 850 are off the charts, but that means nothing at the surface is they can't be tapped into. Sustained winds will be the most impressive (20-30 mph) with gusts 40-50 and the typical spots that get above 60 will do so. But this isn't a region wide 60+ gust setup

I

 

4 minutes ago, weatherwiz said:

I've played up the past several wind events..didn't downplay any of them. 

This isn't a low topped convective situation either. Outside of the intense forcing this is very little instability to work with aloft...certainly not enough for any convective elements. And that whole "models can't handle low level lapse rates" thing made zero sense. Low-level lapse rates are going to be garbage...all you have to do is look at the thermal profile in the lowest 10,000 feet.

Torrential rainfall is not going to mix winds down, in fact, torrential rainfall will help to induce an inversion. This is not a big wind setup. Sure...winds at 925 and 850 are off the charts, but that means nothing at the surface is they can't be tapped into. Sustained winds will be the most impressive (20-30 mph) with gusts 40-50 and the typical spots that get above 60 will do so. But this isn't a region wide 60+ gust setup

It is just too bad that your met degree and years of experience pales in comparison to the knowledge that some individuals  have acquired on the internet........

[CoastalWx]

I will say this has a bit more of an inversion than other storms, but also a stronger LLJ. And maybe inversion is too aggressive......more like shitty low level lapse rates. I’m not sure how it shakes, but if those lapse rates steepen a tad....look out.

Also, there may be a quick one hour pulse of strong SW winds as we start to CAA. Right after the line of heavy rains and we get quiet for an hour or two. This probably happens more in RI and SE MA. 

[Ginx snewx]

6 minutes ago, Great Snow 1717 said:

I

 

It is just too bad that your met degree and years of experience pales in comparison to the knowledge that some individuals  have acquired on the internet........

Lol if you only knew

[Ginx snewx]

5 minutes ago, CoastalWx said:

I will say this has a bit more of an inversion than other storms, but also a stronger LLJ. And maybe inversion is too aggressive......more like shitty low level lapse rates. I’m not sure how it shakes, but if those lapse rates steepen a tad....look out.

Also, there may be a quick one hour pulse of strong SW winds as we start to CAA. Right after the line of heavy rains and we get quiet for an hour or two. This probably happens more in RI and 

Any dry slot in between bands could promote quick mixing as well

[weatherwiz]

4 minutes ago, Ginx snewx said:

Hmmm

The guidance continues to beat the drum on potential for a high end,
potentially damaging wind event. As the parent low generates a
secondary low along the frontal boundary over the mid Atlantic a
very robust low level jet develops that would be unusually strong
for this time of year. We`re talking 75 to 85 kts at 925 mb and 85
to 95 kts at 850 mb. As mentioned by the previous forecaster, the
EPS and NAEFS ensembles continue to depict anomalies of >5 standard
deviations and maxed out percentiles! So, while historically these
southerly wind events struggle to mix down and modeled soundings
would indicate as much, the anomalous warmth that comes with it
should help to break that subtle inversion enough to mix down some
of those wind, and with that magnitude, even 50-60% would cause
scattered downed trees and power outages. Compounding that risk is
the heavy downpours and potential fine line of convection moving
through in the morning that would help to mix down the stronger
gusts

 

n additional concern is with strong to potentially damaging
winds Thursday night into early Friday morning. Models continue
to show 65 to 75 kt winds at 950 mb during this period. The core
of this low level jet is most likely to pass over Long Island
and southeast Connecticut. Forecast soundings indicate an
inversion around or just below these high winds and this is
typically a difficult forecast on how much will mix down to the
surface, but with models continuing to show signs of a potential
squall line or convective cold frontal band, this would enhance
the chances for stronger winds to mix down to the surface. If
this type of rain band/squall line materializes, the winds would
effectively weaken considerably once it passes, similar to what
occurred on November 15. Advisory-criteria winds could occur
for the inland areas. Strongest sustained winds and gusts would
be from late evening Thursday through around daybreak Friday.

If there is convection involved then we certainly would see high wind potential...in fact, we would probably see widespread damage and power outages. There is no doubt this LLJ is about as anomalous as you'll ever see, but we need to tap into that. It's always tough to gauging what percentage can be mixed down...sometimes its as high as 50%...other times it can be more around 30%. 

I also agree, the llvl warmth here plus the dews is something you certainly want to see when looking for wind potential...but the issue here is the distribution of warmth in the lowest say 4-5km is just too even...hence the crappy lapse rates. Sure this warmth will help to mix somewhat, but due to clouds and precipitation (you'd have to figure lots of showers ahead of the main line) that mixing is going to be very limited...and the best mixing would occur well prior to the core of the LLJ.

 

If the core of the LLJ was ahead of the main rain rain then there would certainly be a window for very damaging winds. However, given it coincides with the timing of the heaviest rain, we are likely going to be rather stable and probably have a tough time mixing even close to 1,000'.

 

Even looking at bufkit soundings for BDL...you have to change the mixing depth to a 20 to even get big gusts. 

2 minutes ago, Great Snow 1717 said:

I

 

It is just too bad that your met degree and years of experience pales in comparison to the knowledge that some individuals  have acquired on the internet........

Well too be fair school is like 95% math and not a ton of forecasting. forecasting is really more about experience and applying knowledge and someone who has been doing that for day 20 years will probably outforecast someone who just freshly graduated. 

[weatherwiz]

6 minutes ago, CoastalWx said:

I will say this has a bit more of an inversion than other storms, but also a stronger LLJ. And maybe inversion is too aggressive......more like shitty low level lapse rates. I’m not sure how it shakes, but if those lapse rates steepen a tad....look out.

Also, there may be a quick one hour pulse of strong SW winds as we start to CAA. Right after the line of heavy rains and we get quiet for an hour or two. This probably happens more in RI and SE MA. 

bufkit soundings actually hint at this very well.

Also, it seems from past experiences that a stronger LLJ can often lead to a stronger inversion (especially if the strength of the WAA aloft exceeds the strength of WAA at the sfc). 

[dendrite]

8 minutes ago, weatherwiz said:

, I've played up the past several wind events..didn't downplay any of them. 

This isn't a low topped convective situation either. Outside of the intense forcing this is very little instability to work with aloft...certainly not enough for any convective elements. And that whole "models can't handle low level lapse rates" thing made zero sense. Low-level lapse rates are going to be garbage...all you have to do is look at the thermal profile in the lowest 10,000 feet.

Torrential rainfall is not going to mix winds down, in fact, torrential rainfall will help to induce an inversion. This is not a big wind setup. Sure...winds at 925 and 850 are off the charts, but that means nothing at the surface is they can't be tapped into. Sustained winds will be the most impressive (20-30 mph) with gusts 40-50 and the typical spots that get above 60 will do so. But this isn't a region wide 60+ gust setup

Rain can stabilize things, but not always. Even if we’re “mixed” it’s going to be moist adiabatic with the high dews advecting in over the pack. It gets more difficult in the foothills and sheltered valleys where the latently cooled air can put up an easier fight, but there’s going to be a corridor just inland where the pack will go relatively quickly and the winds will be roaring off the deck with 59/59 at 2m. Idk...I can kinda see this going either way, but I feel like you’re getting a little Popeish here with the angry anti-wind posts and trying to pound your chest while going against the grain. I mean we get it, we know where you stand. But the NWS is hitting the concern pretty hard and some other mets too. Hey, I hope you’re right...we don’t need trees falling on travelers Christmas morning.

[Ginx snewx]

3 minutes ago, weatherwiz said:

If there is convection involved then we certainly would see high wind potential...in fact, we would probably see widespread damage and power outages. There is no doubt this LLJ is about as anomalous as you'll ever see, but we need to tap into that. It's always tough to gauging what percentage can be mixed down...sometimes its as high as 50%...other times it can be more around 30%. 

I also agree, the llvl warmth here plus the dews is something you certainly want to see when looking for wind potential...but the issue here is the distribution of warmth in the lowest say 4-5km is just too even...hence the crappy lapse rates. Sure this warmth will help to mix somewhat, but due to clouds and precipitation (you'd have to figure lots of showers ahead of the main line) that mixing is going to be very limited...and the best mixing would occur well prior to the core of the LLJ.

 

If the core of the LLJ was ahead of the main rain rain then there would certainly be a window for very damaging winds. However, given it coincides with the timing of the heaviest rain, we are likely going to be rather stable and probably have a tough time mixing even close to 1,000'.

 

Even looking at bufkit soundings for BDL...you have to change the mixing depth to a 20 to even get big gusts. 

Well too be fair school is like 95% math and not a ton of forecasting. forecasting is really more about experience and applying knowledge and someone who has been doing that for day 20 years will probably outforecast someone who just freshly graduated. 

1717 is just a trouble maker. You and I know Wiz, we can discuss anything without personal attacks. I agree with most of your assumptions however 2 concerns, fine line convection and dry slots in between rain bands. I so don't want this storm

[Great Snow 1717]

1 minute ago, Ginx snewx said:

1717 is just a trouble maker. You and I know Wiz, we can discuss anything without personal attacks. I agree with most of your assumptions however 2 concerns, fine line convection and dry slots in between rain bands. I so don't want this storm

LOL......