wdrag

Door opens for melting and rain as temps warm to normal. Timing.

Following up on Don's post of several days ago regarding the disconnect in the BOM QPF vs snowfall; here is a reply from Pivotal that confirms Don's post of several days ago. The is a frank response that I do not want shared as an insult-put down for anyone trying to improve our science. Thank you for your respect on this particular post. Hi Walter, Thanks for reaching out. The short answer is that there are sometimes internal inconsistencies within a single NBM run as you switch between forecast fields. The NWS NBM is a hodgepodge blend of numerous models and ensembles. Confusingly, the composition of which models are used in the blend changes depending on the forecast time and even the forecast field. We do see the discrepancy you mentioned from the 19z/04 NBM run, and have verified that this discrepancy between the snowfall and QPF variables actually exists in the raw NBM data files from NCEP. For example, in the 6-hour period between forecast hours 53-59 of that run, the data file shows ~0 QPF on Long Island but up to ~1" of snowfall. Our best guess is that NOAA MDL uses a different blend of models to produce the QPF field vs. the snowfall field, and in this case, one or more models that were only used for snowfall had a more northward storm track. The official NBM documentation here should provide more details, although it is pretty dense and loosely organized: https://vlab.noaa.gov/web/mdl/nbm-documentation It may also be worth reaching out directly to NOAA MDL if you want a definitive answer on how they compute a specific NBM variable at a specific forecast lead time. If you do reach out and they ask which NBM version we're using, you can let them know that we are using the publicly available grib2 files from NCEP. Best, PW Team

My only thought on 96 and even through 2010 ish... models weren't nearly as good. Those of us who're in our 70s and older (hands please) , have witnessed spectacular improvements in general model consensus through at least 5 days... even this storm just passed was thread started the 30th, couched in the uncertainty (see p1 of the Jan 6 thread if interested)). Maybe even those on here who're only `60 (born in 65), probably are aware of the spectacular improvement. ALL of us should now know how helpful the short term models are (HRRR(X) and RAP. Ditto the science of medicine but I won digress.

Today through Thursday I84 corridor: Check for black ice this morning-residual moisture freezing. Windy and winter cold. Scattered northwest wind gusts 40-50 MPH! Isolated power outages especially Thursday when ridge gusts in PA/northern NJ and eastern NYS might reach 55 MPH! January 19-22 mainly interior northeast USA just northwest of Interstate 95 from DC to Boston up through NYS and the Great Lakes. It becomes wet or white depending on location but storminess increases the last 10 days or so in January as temps moderate. This is when I think we have a decent chance of a snowstorm but timing is everything. Modeling continues to open up the eastern half of the country to moderating temps (seasonable) and better chances for significant precipitation.

DC-Baltimore through Philly-NYC-BOS along and north of I95... a small snow event seems likely Saturday the 11th with dustings to possibly at worst 4 inches but am not playing up a major event. This could have some travel impact but far too early to be sure. Maybe the most favored area for snowfall is the immediate coast of NJ/LI/CT. There's still a small chance this storm will blow up bigger and closer to the coast. Treated roads melt but timing of occurrence will have a bearing on the hazard potential, especially with ice cold surfaces preceding this event. I can handle a weenie roast, especially if 4+ for NYC on this event. Right now all modeling through the 06z/7 cycle is kind of merged into the above paragraph. I haven't seen all prior posts, but for what it's worth, I do not use analogs. I treat each event differently, not trying to profile it as one or the other category. Yesterday a good example up here (suppression factor). A lot of these events have a lot to do with banding physics...models are helpful but imperfect. I'll post the CoCoRaHs snow totals in the other thread at about 10A.

Not sure where this started outside of our subforum at least a day prior to us starting the thread. It's not good that we egg it on. For now, I'm pretty strongly against this happening... one big reason... the ECMWF ensembles 6th-12th are basically drier than normal... they can adjust on the edges closer to LI with time, but I dont see an above normal weekly amount of qpf 6th-12th... that would be your super bomb. I've been wrong before so my door is open to a low or very low prob possibility but I think the WPC WSSI P is the prudent way to keep this in perspective. Tone it down until the EC comes on board and through 18z/6... it is not, at least so far. We are hungry for a big snowstorm - I understand. I foresee about 0.1 to 2" from whatever happens the 11th in our NYC subfzorum... more or less similar to today's first January snowfall on LI. The bigger problems I think are further south somewhere in the interior of NC and interior Virginia/DE Cape May region where I'd monitor for delays and possible plan changing weather late 10th-11th.

Lets give some credit to the HRRR and RAP for modeling some snow up here to I84. Canadian was not very good. EC decent.

Hi... I'm reluctant to buy into a big storm right now... IF NO PHASE between the northern and southern streams, then no big storm. Many members of the 12z/6 GEFS are running the northern stream short wave out ahead of the southern stream. That to me is out to sea and snow ice favored NC-Delmarva- s NJ. The mean trough on the GEFS would allow snow up here but concerned this 5H flow is going to look different come Friday (less high amplitude N/S- troughing). For now the EPS is meager, and WPC D6 qpf and winter wx are also meager. That can change but am thinking conservatively and not planning big up here.

Wantage Nj 740' MSL flurries...small flake. SB 856A.

Flurries into Mt Cobb PA exit 8 I84 act 2000 feet, under the radar scope bright band east of Scranton.

nw NJ-nePA-Orange County NY and Kinnelon-NYC-LI 9AM-3PM...a dusting to possibly 1.5". We're on the fringe here. The northern part of Sussex County, northern Pike County PA to Lords Valley and Mt Cobb PA on I84 as well as all of Orange County might escape with just some late morning flurries-uncertainty? my 2c on expectations.

Not thinking any thread for 1/11ish tonight...and if it starts tomorrow, probably hold off til dinner time. Mainly NC-Delmarva, at least until the Canadian joins the intermittent fray up here on LI.

MPING is back. Delete app and reacquire. Certificates expired this morning per mPING

Bashing is social media. Many bashers are self centered with little care how their words play. wonder what their families are like? That’s the cost of freedom. Just take something good out of it, maybe that they pay attention to the forecast.

fwiw... Flight aware showing what I see as at least 50-70% flights cancelled in and out of MKC and STL at this time. Not a huge storm but a long narrow one.

mPing? anyone know what's happening. Getting a response about impersonating. Did we have to reload it? fwiw... might have more flakes today in Wantage then we see tomorrow??? lots of fluffy flakes coming down... been off and on the past 3 days but today is the best yet.

Seasonal since 11/20 via CoCoRaHs obs: If interested click for clarity.

Just have to wait it out... I think we'll be seeing 12-15-1 ratios on whatever we get that is more than .05 melted, in part due to banding. The banding graphics will post around 1P (if I have time-3 year old running around Opa=Grandpa in Dutch). Thank for very much your compliments! Many good-excellent posters herein, observers of the guidances and their nuances. I don't post elsewhere except on my FB group, due to the overall good history with AMWX since my BOX days, plus I don't like the insta-dissapear posts elsewhere-- I like to look back and take my words to be reasonably accurate with perspective and try to act responsibly, more so than even in my later NWS days. The Discord platform transition 2 years ago basically set me aside from sharing on 33andrain, but do know it too is valuable for interested community. I just did not like the Discord process, in part cause I couldn't follow events very well. I'll stay here til the NWS gets out there, like NHC, on getting the message out clearly and well advance- out to 7 days in each office Then I'm done and can sleep in. For now, I think the NWS is too steeped in it's own messaging imitations and is not simply and effectively communicating beyond 3 days. it just isn't. Guidance has outstripped the process. Just my opinion. Change for NWS will be driven by outside forces.... internally it is too conservative. Again, my opinion but I would not be welcomed back- I do live with that, even though I'm human and like to be wanted. I would not fit their process. Let's see how things evolve tomorrow... will this be the first measurable of January in CP.

I like the JM observation on HRRR especially valuable inside of 24 hours, but somewhat speculative maybe too amped beyond 24 hours. I think that is true..added the Philly area qpf and snowfall about 48 hours ago... HRRR and HREF too amped. RDPS too far south and so it was less. There was thunder in the DC area with that 48 hours ago event (late Friday afternoon). Here's the resultant qpf and snowfall per CoCoRaHs.

Letting it play out... fringe at most I80 north.

Not starting 1/10-11 thread till tomorrow is nearly done. Canadian is not buying it. It also is the one model pretty far south on this one. Maybe another behind it 17-20 with another shot of cold in between those two opportunities.

I think strong isentropic lift with sw jet at 7H/8H in the Virginia's with 8H trying to form a low in PA-NJ by 00z/7. The mesoscale models are holding onto the trough structure longer as we come toward T0 (Monday)... so presuming it has the upper low right in the OV, it wont disappear as fast as modeled-mushed by the globals. There wont be much northerly BL flow into the system prior to its arrival on the 6th so dry air advection I dont think is a player. It has basically what is out there now, a 15-20 degree T/Td spread. It will take awhile for snow aloft in any CSI Band to work down to the ground up here around I80. There may be some small ocean effect contribution along the NJ coast? I have to think the globals will drift north tomorrow... or I've interpreted wrong. First thing I have to see is there Canadian come way north. Just not what I expected from the Canadian (GDPS-RGEM). For now I think it the southerly outlier. That's it for me tonight. Thanks for the MDL NBM reply.

Watch the 18z EC and 00z/5 global models. Either the globals are too far south or you'll see a sudden shift north by 30-60 miles. I am seeing too many members trying to hook northeast at 5H up into NYS-CT. The 21z RAP continues its northward trend. Bothersome. Wouldn't take much for the confluence zone to shift north past I84. WPC and WFO's have all the guidance, more than what I'm seeing but something is going to eve to change south in the short term mesoscale models (ALA the oddly south Canadian) or the globals will be bleeding north in the next cycle or two. We'll know more by morning. Globals suppressed vs mesoscale modeling now. Compromise? I'll check the HSD and QPFPMD but I continue to think a little snow throughput NJ-LI til I see the mesoscale models move south from the 18z modeling.

I've notified Pivatol Weather via email regarding the qpf snowfall disconnect.

CTP and PHI hold the watch til at least one more forecast cycle. Guessing LWX will warn but unsure...still nothing from them at 346PM but they may be coordinating with partners, writing up whatever. No matter what happens Philly-DCA Monday, I think those cities and in-between I dont want to be trying to drive in a timely fashion and get to work that for most of us could easily hold off a day.