Tracking JAN 29th 2022 'The Phase'

Nice improvements on the 6z GFS as well with the s/w energy and phasing, though still remains east of everything else. The improvements at 500mb is really all you need to see from the GFS as it probably won't catch on until he end lol

Sanchize06 wrote:Nice improvements on the 6z GFS as well with the s/w energy and phasing, though still remains east of everything else. The improvements at 500mb is really all you need to see from the GFS as it probably won't catch on until he end lol

Agree the Gfs closes off later than other guidance. 3 hours sooner would be great. But got ylto admit the trends are good

skinsfan1177 wrote:

Sanchize06 wrote:Nice improvements on the 6z GFS as well with the s/w energy and phasing, though still remains east of everything else. The improvements at 500mb is really all you need to see from the GFS as it probably won't catch on until he end lol

Agree the Gfs closes off later than other guidance. 3 hours sooner would be great. But got ylto admit the trends are good

Yeah, not much to dislike at all about the 0z and 6z suite

06z 12k NAM closes off the Delmarva.

What does that mean

The latest report from Mt Holly released just after 4 am. They are south of where most of you live, so their forecast and hype will be what most of you are hoping to start hearing out of Upton etc...over the next 24 hours (except LI, y'all locked in!). If you are at all familiar with Mt Holly's 'it just don't snow at the coast' mindset, this language is just incredibly encouraging at this point.



Their review of the model mayhem. Pretty colorful and quite accurate:

It has been a live-or-die-by-every-model-timestep sort of night here at the office. And what the models give, they also take away, which basically describes the model variability we have seen the past couple of days with the potential winter storm for our region Friday night and Saturday. The 00z suite has made a notable consensus shift westward with the low tracking just off the coast, but the high volatility/variability remains. The 00z GFS is a far-east outlier solution and basically brings little snow to the CWA for the whole event. Meanwhile, the 00z NAM returned the snow to our area, in a large return of departure from the 18z NAM no-show (no-snow) event. The 00z CMC brings a blockbuster storm to the area, with widespread warning criteria south and east of the Fall Line; the 00z ECMWF is only somewhat drier than its 12z predecessor run. The 00z UKMET went sharply west, with meaningful QPF/snow for much of the area.

The model volatility with this system has been something to behold. Such run-to-run spread is typical/expected for these types of events, given the highly complicated interdependent phenomena involved. However, simple analysis of the spread in the National Blend of Models is enlightening; the 04z NBM V4.0 (V4.1) 50th percentile storm total snow for the Philly area was around 1.5 (1) inch(es). The 75th percentile storm total snow was around 8 (10) inches, or roughly an order-of-magnitude difference between the median and the upper quartile. Bottom line here: the storm total snow forecast remains highly uncertain and subject to large changes in subsequent forecasts.



Next, they review what to watch for as the storm develops- which of course we already know, but it's a great reminder of how much work remains and the interim results that are still so necessary for success Friday night/Saturday:

Observation-wise, it will be critical to assess three regions/phenomena as the event unfolds: (1) the strength/depth, orientation, and speed of a northern-stream digging vort max through the Midwest on Friday morning, (2) the orientation and speed of a southern-stream vort max in the southern Plains around this same time, and (3) the low-level response to the phasing trough near/off the Southeast coast Friday night (e.g., the 850-mb heights and winds). The progressive solutions have a more compact and faster northern-stream vort max and a slower southern-stream vort max, which results in upper low development farther east (and generally too far east for our region to see substantive snow); the snowier solutions acquire phasing and neutral to negative tilt of the large-scale trough more quickly (and thus, farther west). Trends in the low-level response are obvious Friday night -- the NAM/CMC (aside from the errant 18z NAM simulation) are positioning the 850-mb low/trough farther southwest.



Then, they simply discard the GFS as an outlier that doesn't make sense and proclaim that their forecast will be made without it!!!  

The GFS is much noisier, exhibiting little trend. Notably, the 00z GEFS featured unusually low spread, which makes me wholly suspicious of the deterministic and ensemble output from its suite. With the model camps making the GFS more and more of an outlier, tonight`s forecast is generally a non-GFS consensus blend. This preserves a considerable amount of continuity to fields of importance such as PoPs, QPF, and snow amounts.



And then finally, their forecast. The takeaway on the forecast is, all snow and heavy snow, as long as you get the track...

The main changes were to sharpen the gradient of snow totals near/northwest of the I-95 corridor, with 1-3 inch totals northwest of the Fall Line, 3-6 inch totals in the urban corridor and immediately adjacent areas, and 6-12 inch totals roughly from Easton, MD, to New Brunswick, NJ. Again, there is enormous uncertainty with these forecast totals. If the more progressive solutions pan out, very little snow may occur in a large chunk of the area. If the slower/stronger solutions pan out, heavier totals would occur at least to the Fall Line. Continue to monitor the forecasts, as large changes may occur leading up to the event.

Based on the forecast totals, we have issued a winter storm watch for all of Delmarva, far southeastern Pennsylvania, and most of central and southern New Jersey from 7 pm Friday to 7 pm Saturday. Will fine-tune the timing once warnings/advisories are issued, but this is the general time window of concern for our area.

Other impacts and forecast considerations...Winds will be a big factor with this storm, with north winds of 10 to 20 mph becoming northwest 15 to 25 mph on Saturday. Gusts of 30 to 40 mph will be common, with higher gusts possible (especially near the coast and in the higher elevations). With snow falling for much of this time, very low visibilities and blowing snow are possible. Conditions may become very hazardous near the coast on Saturday.

Notice at the very end...that little tease to the B word. Man, o man...all I got to say to this storm was said something I learned on the radio 40 years ago: Burning the ground, I break from the crowd, I'm on the hunt, I'm after you!

Let's Get It!!!!

Carvin wrote:What does that mean

Pretty sure heehaw said that was the ideal location for the low to close off for a bench mark track which gives the best chance for an area wide hit. So, good news...

GREAT 500.MB ULL developemnets overnight.
Day of tracking!!
GFS IS LOST.makes baby steps west.

GAME IS ON!!

I have to say this is one of the more challenging snow maps I've put together.  I'm open for the good and the bad about it.  Just be respectful.

My method.  I looked at 7 different models including global operationals, their ensembles, as well as several short range hi res models.  I looked at all of their 500mb and surface tracks, then looked at all the total QPF maps and created my zones.  I then averaged the western and eastern parts of each individual zones QPF taking 4 numbers from each model within a given zone(an eastern number and western number).  I averaged the 4 values for each model first, and then took that avg for all 7 models to get my overall avg for a particular zone.  I then looked at temp profiles to account for ratios and sprinkled in a little intuition and that's how I came up with my totals.  Obv there is a high degree of uncertainty as if the GFS an the GEFS are correct, and their are a few others that are really east with this sucker, the overall QPF will drop off significantly.  If I removed the GFS and its ens from the equation all other models have a really nice event for all.  Let's see what today brings.  

SENJsnowman wrote:

Carvin wrote:What does that mean

Pretty sure heehaw said that was the ideal location for the low to close off for a bench mark track which gives the best chance for an area wide hit. So, good news...

Yes it is a great location for NYC C Metro.
You closest itboff and it will track NNW a bit indside the proverbial BM. IF and I say if we can close it off 3 hours sooner then OHHHH NELLIE!!

So are all possibilities still on the table ranging from area wide roidzilla to a much smaller event for most?

sroc4 wrote:I have to say this is one of the more challenging snow maps I've put together.  I'm open for the good and the bad about it.  Just be respectful.

Good call. Can’t wait till the short range models get in better range. If the low closes off the Delmarva the totals are doubled in all areas.

sroc4 wrote:I have to say this is one of the more challenging snow maps I've put together.  I'm open for the good and the bad about it.  Just be respectful.

I love the tolerance key there +/- !!
Engineering at its best. Usually we give 5% not 100 LOL!! Great work and thanks for sharing.

sroc4 wrote:I have to say this is one of the more challenging snow maps I've put together.  I'm open for the good and the bad about it.  Just be respectful.

My method.  I looked at 7 different models including global operationals, their ensembles, as well as several short range hi res models.  I looked at all of their 500mb and surface tracks, then looked at all the total QPF maps and created my zones.  I then averaged the western and eastern parts of each individual zones QPF taking 4 numbers from each model within a given zone(an eastern number and western number).  I averaged the 4 values for each model first, and then took that avg for all 7 models to get my overall avg for a particular zone.  I then looked at temp profiles to account for ratios and sprinkled in a little intuition and that's how I came up with my totals.  Obv there is a high degree of uncertainty as if the GFS an the GEFS are correct, and their are a few others that are really east with this sucker, the overall QPF will drop off significantly.  If I removed the GFS and its ens from the equation all other models have a really nice event for all.  Let's see what today brings.  

Good 1st call right in line with nws for my area anyways. I'm sure there will be shifts and you showed that which was really smart.

amugs wrote:

sroc4 wrote:I have to say this is one of the more challenging snow maps I've put together.  I'm open for the good and the bad about it.  Just be respectful.

I love the tolerance key there +/- !!
Engineering at its best. Usually we give 5% not 100 LOL!! Great work and thanks for sharing.

I hear you mugs. But like I said in my edit above, if the GFS is right that's how much you have to shift the totals. Just for perspective say for ZONE 2 if I remove the GFS and the GEFS avg QPF from my overall avg you get an avg QPF of 1.06". If you only avg the GFS and GEFS the avg QPF is 0.35". At a 12:1 conservative ratio that's a difference of 4.2"-12.72". So this really does have really high bust potential high and low.

You know I just realized where's Algae? He is usually very involved in storms and I don't think he has posted once hope he is ok.

Winter storm watch issued. This one going to be fun.

jmanley32 wrote:You know I just realized where's Algae? He is usually very involved in storms and I don't think he has posted once hope he is ok.

I was wondering the same.

He was always good for those 4:30am write ups, either good or bad but he gives it to you straight.

Al post!!!!!!!!!

Joe Snow wrote:Winter storm watch issued. This one going to be fun.

It depends on how you define fun. A gut punch to the solar plexis fun? That's still one of the options. An all out snow storm for many, that's fun but still not guaranteed. I'd have to say Doc and Alex are in the best locations right now.

Euro has trended more east this run

skinsfan1177 wrote:Euro has trended more east this run

saw that. A little more east and somewhat stronger. Not overly bad but not the direction we wanted.

Euro is east a tad but 500 closing off was a matter of 2-4hrs later than the prev run. 2-4 hrs earlier and it’s back to where it was maybe even stronger. These little minor details appear to be the wipers. We shall see at 12z

For a 1'+ snow on the 95 this ULL close off needs to be concentric and organized.  This as shown won't drop the big snows as it's in a consolidation phase.  That is the key in that how quickly that gets its act together.  If this it tight at that latitude NYC gets 12-18" no problem.

I remind everyone this can bust really high either way. Don't get too excited or down yet as intricacies of the storm will unfold.

But I'm looking for how close surface low forms near the GA coast. Closer it is more likely it goes inside BM.
That is determined by how quickly the 500mb trough can go neutral as that will spawn cyclogenesis closer to the coast. These are fine details but they determine a whole lot.

@sroc4 nice first call map! I agree with it whole heartedly.

@Sanchize06 and @skinsfan1177 thanks for doing some PBP early this morning. Easy enough for me to get caught up

heehaw453 wrote:For a 1'+ snow on the 95 this ULL close off needs to be concentric and organized.  This as shown won't drop the big snows as it's in a consolidation phase.  That is the key in that how quickly that gets its act together.  If this it tight at that latitude NYC gets 12-18" no problem.

We need to factor in one important detail not mentioned. We have record high STT’s for the month of January. That could lead to faster pressure falls/ ULL closing than what the global models are showing. Once in better range the meso models will have a better handle on this.

You can already see our lead energy coming down into Utah on water vapor imagery, which is frankly pretty far west-southwest. Remember, this is the southern energy which we badly need to eject east and phase into the mean trough.