Thursday's Mothrazilla, Part II: First Forecast

Icon definitely expanding the precip north.

18z



00z



Run hasn’t finished

Great potential for this storm and looking forward to what it does. Great write up Frank as usual. What are looking at with timing? Start-Finish? It's looking like it may continue into Friday as well.

This jet streak is as Frank said the.most impressive so far this winter for its strength and ...length stretching back to the GOM



JMAN its a long duration storm

Fededle22 wrote:Great potential for this storm and looking forward to what it does. Great write up Frank as usual. What are looking at with timing? Start-Finish? It's looking like it may continue into Friday as well.

Depends

If the storm consists of just the WAA then 9am-4pm

If the storm consists of WAA and CCB then 9am-9am

Uptons discussion this am.


.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
The focus this period shifts to another southern branch storm
system that will interact with a polar airmass across the
region, continuing in what has been an active month.

A departing polar vortex across eastern Canada and a deep-
layered SW flow emanating from the southern branch longwave
trough over the Plains will provide confluent flow to the north,
allowing polar high pressure to strengthen across the NE
tonight. At the same time, an active frontal zone along the
eastern Gulf of Mexico, extending along the SE and Mid Atlantic
coasts, will funnel a series of lows that will pass south and
east of the area Thursday into Friday. Ahead of the first wave,
snow will break out from SW to NE Thursday morning into the
afternoon.

Guidance continues to trend colder with the system with the low
track generally near the 40n...70W benchmark. However, global
models are in good agreement with a long period of light to
occasionally moderate snow through Friday as multiple waves
passes to the SE. The NAM remains an outlier with strong
frontogenetic banding to the NW of the first low on Thursday
with the potential for heavy snow, especially along the coast.
It produces liquid equivalent amounts of a half inch at the far
NW corner of the Lower Hudson Valley to over an inch across the
NYC metro and LI by early Thursday evening. There is also a
strong upper jet to the NW of the area. However, in assessing
the guidance, the better jet dynamics appear to come in Friday
as the RRQ of the upper jet approaches. Additionally, while
there is a strong baroclinic zone to the NW of the low track,
the low is fairly weak and the best thermal forcing may reside
just south of the area. Overall,the NAM seems to be overdone
with the lift, but at the same time it has been consistent over
the last several runs. Still though, it like the global models
has continued to shift to the south with the frontal zone and
low tracks. This will have to be watched closely today to see if
it falls into the consensus with a longer, drawn out snowfall
event. In fact, much of the guidance points to snowfall amounts
of 6 to 8 inches across the area, but over a 24 to 36h period.
Warning criteria is 6 inches or more in 12h, or 8 inches or
more in 24h. The latter is looking more likely at this time.

Additionally. the ECMWF and GGEM indicate some of this snow
could hang on into Friday evening/night as the last piece of
southern branch energy kicks out. The GGEM even brings moderate
to heavy snow into eastern LI/SE CT. Thus, the Winter Storm
Watch has been extended into Friday.

As for ptype, this is looking to be a mainly snow event with
perhaps some mixing with sleet across LI and the NYC metro
Thursday night into Friday. If that does not happen, the higher
snowfall totals could very well be at the coast. For now,
going with a uniform 4 to 8 inches across the entire forecast
area.

Models are struggling with how far north to bring the frontogenesis and how much an effect the coastal will have.  Any chance to approach 1' on this truly depends on good frontogenesis from the WAA.  Without that we are < 8" on this one IMO.  

I like what Mt Holly and Upton have for now.

GM all so after reading the Upton discussion it appears the NAM is being discounted for tgat heavy banding front end thump? And this may end up being a long WWA for 6 to 8 inches over 36 hrs? That's pretty darn light snow. I'd like to hear what Frank's take on that is cuz he was talking about a super heavy area for a period. I thought at this point the hi res models would be do better than globals. Guess we will see.

jmanley32 wrote:GM all so after reading the Upton discussion it appears the NAM is being discounted for tgat heavy banding front end thump? And this may end up being a long WWA for 6 to 8 inches over 36 hrs? That's pretty darn light snow. I'd like to hear what Frank's take on that is cuz he was talking about a super heavy area for a period.  I thought at this point the hi res models would be do better than globals. Guess we will see.

Certainly not discounted Jon but taken as an outlier since it is regarding its temp profiles and strength of vertical lifting.  That said is has been consistent in its runs including 12z today.  Cant discount consistency.

12z NAM

sroc4 wrote:

jmanley32 wrote:GM all so after reading the Upton discussion it appears the NAM is being discounted for tgat heavy banding front end thump? And this may end up being a long WWA for 6 to 8 inches over 36 hrs? That's pretty darn light snow. I'd like to hear what Frank's take on that is cuz he was talking about a super heavy area for a period.  I thought at this point the hi res models would be do better than globals. Guess we will see.

Certainly not discounted Jon but taken as an outlier since it is regarding its temp profiles and strength of vertical lifting.  That said is has been consistent in its runs including 12z today.  Cant discount consistency.

I agree I hope we see a period of heavy snow if it's light I dunno how much will accumulate other than on top snow as it was super muddy here but it's 24 now so that prolly hardened up. Will be interesting to see how this pans put. Kinda a weird set up.

The 'mega' band that was shown yesterday seems to be off the table. The trend on the hi-res NAM shows how the frontogenic forcing has weakened in four consecutive model runs.



My updated snow map:

Frank_Wx wrote:12z NAM

looks like nam backed off on the totals by a few to several inches but still within ur map area and amount, do u think theres still a chance somewhere sees 12+ or do u think the NWS is right in that the qpf is too high.  Are you in FL now?  If so kudos to stay on this for us even on vacation, don't party too hard haha

OMG its wed. duhh. wow that surely is a flurry at best for that long.

Well nvm frank haha, that stinks only 3-6 meh thanks for your efforts still. So no snow today in otherwords.  4am today? Its def not snowing since 4am. or 4pm today or 4am Friday morning, confused at the timing?

jmanley32 wrote:

Frank_Wx wrote:12z NAM

looks like nam backed off on the totals by a few to several inches but still within ur map area and amount, do u think theres still a chance somewhere sees 12+ or do u think the NWS is right in that the qpf is too high.  Are you in FL now?  If so kudos to stay on this for us even on vacation, don't party too hard haha

Not yet, I leave for FL late Friday. I'll be there until the 28th.

As for 12+ - that is not likely and really never was. The highest I was thinking was 8-12, but those amounts will be concentrated to specific areas who benefit from the WAA (front end thump) of snow AND the CCB band that tries to develop late Thursday into Friday. The coast - ESE of 95 - is going to battle temperature issues.

Areas where there is 90% snow I think widespread 6" with locally higher amounts to 8".  The problem is the warm nose is just not possible to know at this lead time, but the less intense WAA probably means less chance of warm nose too.  It may just be a trade off in some regards.  One thing that seems to be off the table are locally 1' amounts at least right now.  But you just never know how the game unfolds and that's why this is so fascinating to me.

jmanley32 wrote:Well nvm frank haha, that stinks only 3-6 meh thanks for your efforts still. So no snow today in otherwords.  4am today? Its def not snowing since 4am. or 4pm today or 4am Friday morning, confused at the timing?

Today is Wednesday....



Although it seems long duration, the precip will be pretty light outside of some moderate bands from the WAA. Then the CCB wraps around Thursday night through Friday morning but I don't think that will be 100% snow for the coast.

Frank_Wx wrote:

jmanley32 wrote:

Frank_Wx wrote:12z NAM

looks like nam backed off on the totals by a few to several inches but still within ur map area and amount, do u think theres still a chance somewhere sees 12+ or do u think the NWS is right in that the qpf is too high.  Are you in FL now?  If so kudos to stay on this for us even on vacation, don't party too hard haha

Not yet, I leave for FL late Friday. I'll be there until the 28th.

As for 12+ - that is not likely and really never was. The highest I was thinking was 8-12, but those amounts will be concentrated to specific areas who benefit from the WAA (front end thump) of snow AND the CCB band that tries to develop late Thursday into Friday. The coast - ESE of 95 - is going to battle temperature issues.

With ur new snow map it appears you feel its going to be well below the NAM amounts too? I mean u basiucally cut it in half, is there a chance that banding still happens? Its kinda odd how this got it really wrong 24 hrs out.

sroc4 wrote:

jmanley32 wrote:GM all so after reading the Upton discussion it appears the NAM is being discounted for tgat heavy banding front end thump? And this may end up being a long WWA for 6 to 8 inches over 36 hrs? That's pretty darn light snow. I'd like to hear what Frank's take on that is cuz he was talking about a super heavy area for a period.  I thought at this point the hi res models would be do better than globals. Guess we will see.

Certainly not discounted Jon but taken as an outlier since it is regarding its temp profiles and strength of vertical lifting.  That said is has been consistent in its runs including 12z today.  Cant discount consistency.

AND it was the one first storm to see the warm tongue and show rain through NNJ before any other caught this. It has done very well with these storms and has ben consistent for 4 runs now on the jet dynamics and the evolution. RGEM has had it and now the GFS. EURO not so much and  CANADIAN. EURO has had us cooler (last storm) and less snowier with storms - it has sniffed them out to back track on them but its EPS shows a snowier solution last night at 0Z. Lets see what the rest of the model suite brings into play here today.

Frank_Wx wrote:

jmanley32 wrote:Well nvm frank haha, that stinks only 3-6 meh thanks for your efforts still. So no snow today in otherwords.  4am today? Its def not snowing since 4am. or 4pm today or 4am Friday morning, confused at the timing?

Today is Wednesday....



Although it seems long duration, the precip will be pretty light outside of some moderate bands from the WAA. Then the CCB wraps around Thursday night through Friday morning but I don't think that will be 100% snow for the coast.

yes i edited my comment to reflect that, im tired and been unemployed (well i work for myself right now, love being my own boss) so sometimes i do not realize what day it is especially first thing in morning.

This is where your moisture fetch comes from

Frank_Wx wrote:

jmanley32 wrote:

Frank_Wx wrote:12z NAM

looks like nam backed off on the totals by a few to several inches but still within ur map area and amount, do u think theres still a chance somewhere sees 12+ or do u think the NWS is right in that the qpf is too high.  Are you in FL now?  If so kudos to stay on this for us even on vacation, don't party too hard haha

Not yet, I leave for FL late Friday. I'll be there until the 28th.

As for 12+ - that is not likely and really never was. The highest I was thinking was 8-12, but those amounts will be concentrated to specific areas who benefit from the WAA (front end thump) of snow AND the CCB band that tries to develop late Thursday into Friday. The coast - ESE of 95 - is going to battle temperature issues.

You didn't leave in time that's why it trended less, thanks for nothing!! LOL totally kidding.

GFS

Frank_Wx wrote:GFS

wow dying out big time nyc area falls right in ur low end. Looking like a minor event at best, but we will see, things can happen as surprises.

I suspect most WSW will go to WWA sometime today. Being the duration does not fall in the category of a warning level event as Upton stated and if Franks totals of 3-6 are right I do not think thats a risky thing to say.

I trust the NAM more this winter inside of 24 hours and the last GFS run looks weird to me. For now I'm expecting a solution closer to the NAM, but that includes an extended period of sleet. I still think most people on this board end up with 4-6" with isolated amounts around 8" depending on banding and mixing.

I think the only way we'll see the higher end totals would be to pool our cash and get Frank on an earlier flight. I see a few open seats on the red eye tonight

essexcountypete wrote:I think the only way we'll see the higher end totals would be to pool our cash and get Frank on an earlier flight. I see a few open seats on the red eye tonight

This actually is the only way, and I would be open to it