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wdrag

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  1. wdrag
    This is the NWS Blend of Models---differs from the local NWS interoffice collaborated forecast (posted earlier in this thread around 627P) and basically a statistical use of the guidance output. This from the 18z cycle. This may be the way the NWS is going in the future. Right now it serves as a baseline for some of the NWS product grids, whereby forecasters modify this guidance per additional model input and forecaster collaboration. Early next week I hope to have more info on the timing of the departure of the NAM/HRRR etc in lieu of the Unified Forecast System (UFS). Some suggestion not for two more years.
  2. wdrag
    Hi: Delayed Interesting guidance herein. 1) 18z GGEM op... snowfall. Max near ABE. in MM. Looks like 20" 2) 00z GGEM op... snowfall. Max near ABE. in MM Looks like 20" 3) Prob of 8" our the next 72 hrs. NYC sitting on about 70% chance. See legend for probs your area. 4) Prob of 18"...bullseye west of Harrisburg so my thinking of Poconos could be very much too far north? I'm still going with that but use your best judgement. 5) NWS 4PM collaborated snowfall only through 7PM Tuesday, 6) NWS 4PM Storm Severity index which takes into account snow load, wind, snowfall etc. 7) Potential Allentown top 20 two - day snow storm? XMACIS evaluation attached. If this is wrong, please let me know. Thanks! I śaw the GFSv16 holding onto 10-24" I78 through LI. Could be right but I am trusting the NWS probs and thinking that eventually modeling will shift a little more north but, jury out. This not only could be power outage snow but also heart attack snow, especially in areas where snow is mostly 31-33F and water equiv over 1.5" I don't think traveling I80-I78 PA/NJ into w LI is a good idea and anticipate many cancels. Check back tomorrow and will begin the OBS thread at that time with baselined snow depth to start. Have a good night.
  3. wdrag
    Heres some SPC HREF from the 12z run showing snowfall (ensembled and not guaranteed but something to consider) by sunrise Monday. I also added the 48 hr mean precip type. These are all subject to error but an idea. Finally the snow depth as analyzed-modeled at 14z/today.
  4. wdrag
    Hi! Will post NWS collaborated snowfall for the PA/NYS/NJ area and hopefully by that time I have an updated NWS ensemble prob of >12" of snow for 72 hours and some SREF probs. It's going to be a nice front end thump for LI. I see models continue edging north and I think they will continue to do so into the 12z/31 cycle and then it's almost here. It definitely begins mid -late Sunday afternoon central NJ, then to NYC-MPO ~ midnight and pummels Monday, probably mostly afternoon-eve. Then the dreaded dry slot LI eastward, tho could be overcome by new IR leafs of WAA which would help change rain back to snow on LI (if my read of rain is correct there on LI???which is debatable). My opinion from op NAM and EC (I don't have any confirmation date yet on the NAM being replaced by the FV3 based UFS and I don't see any SCN, so I presume its' going to be later than March 2021). Anyway from the NAM and EC OP IR and 12z/30 EPS 60 knot ene inflow stagnated over the ne corner of PA, and better snow ratios there, I could be VERY WRONG but I think the 20 to maybe low chance 25" bullseye (or one of?) will be ne NE PA Poconos where best lift. Here's the EC op IR that tells me somewhere upslope region in the Poconos to near BGM or Catskills, will be the eventual bullseye of 20-25" powder. Drifts to 3 or 4 feet. Pummel for 12-18 hours Monday afternoon-night there, under or the east side of the edge of the IR from this 12z/30 operational EC IR projection This lift and favored area is supported by 60KT of ene inflow at 850 MB over southern New England and temps in the Poconos mostly 20-27F. I think modeling currently favors a little to the se of my projected. Use your best judgement. Hopefully in sequence: EC IR 18z/1, 00z/2, 06z/2; dayshift WPC D1-3 qpf with 1.5" NYC area, example EPS inflow at 850MB. Thats lot of moisture transport in weakening 700 MB flow-slower moving once it gets in there; also the 12z/30 EPS snowfall (includes sleet/mix as 10 to 1 so am a little cautious se side of this, and can see boosting the nw side with higher drier fluffier wind blown snow ratios). Strongest wind gusts interior 30-40 MPH late Monday afternoon-evening, while 50+MPH in the probably warning for LI (snow to periods of rain/mix?).
  5. wdrag
    NWS severity index through 00z/2 and their snowfall forecast through 00z/2. NWS
  6. wdrag
    Original Posted Monday at 08:11 AM Jan 25. Del 615AM Saturday: Imperfect probably messy big snowstorm is coming, imperfect in that modeling the past 24 hours is drifting north and suggesting a dry slot late Monday will allow enough warming for sleet (rain LI) to I80 including all of I95 Monday night so that the stratiform burst of 1-2"/hr Heavy snow during Monday, especially afternoon, becomes bands of snow in the interior late Monday night-Tuesday, some areas probably recovering Tuesday with several hours of no precip. So, my own single forecaster point of failure but use of ensembles could be too pessimistic about the sleet/rain intrusion. For NYC... I'll start with 6" with possibly as much 1/2" late 31. Hope that its mostly snow after 00z/2 but even if, snow ratios may be down to 7 or 8 to 1?? I dont' want to cap NYC since am uncertain about dry slot. Sleet/rain/freezing rain may be getting involved Philly to Toms River during Monday morning. There may be a period of near blizzard conditions on LI centered Monday afternoon? BUT, I don't want to call it a blizzard for fear of easily missing criteria. The point of this paragraph, is that I think Monday, especially afternoon should be the worst period of travel and if models continue this, in future cycles through Sunday morning, then I think it would be a recommended no travel for that 6-12 hour period to limit accidents and allow plows to maintain passable-less slippery conditions for first responders. Snow may be wet on LI/Monmouth-northern Ocean Counties in NJ if 6" at 32-33F, we would have power outages... still too early to be sure. CT I84... continue to notice some multimodeled lesser snowfall there, so while I think a big snow there, cautioning myself. Coastal flooding: see NWS statements/flood watches already posted and no change from yesterday with the late Monday evening high tide cycle most favored for flooding (within 2 hours either side of the time of high tide) Graphics are the 00z/30 EPS as a base amount, the 00z/30 EC IR prediction for 06z/Tue showing the dry slot penetration, and the NWS 09z/30 prob for 6" or more of snow by 12z Tues. That's the reasoning basis for this update.
  7. wdrag
    Been away for 5 hours. No change to headline tonight...my guess is that we're locking onto an 8-16" event somewhere between I95-i84 with banding and downslope valley shadows modifying amounts. Usually where the max qpf is where mix/rain intrudes. My guess is we'll see a mix to I95 but I could be too far northwest on that, which benefits all our LI/PA/NJ big snowstorm folks. For now, I suspect somewhat lower amounts NORTH of I84 but reserve the right to change... Yes I could see pockets ~20" but that's with 24 hours snow and no sleet. Not confident enough to make any thread headline adjustments. Here's from WPC this afternoon. Will revisit around 615A
  8. wdrag
    I don't plan on any thread headline upgrades til at least 5P (I'll be offline 1230-4P). Prefer to see the multitude of 12z/29 model solutions/ensembles. No matter the lesser reliability of the NAM after 60 hours and debate on transfer and thence further northward or more eastward development, and the process quite sensitive to the confluence latitude to our north, I am heartened that it is this far north.
  9. wdrag
    Saw EPS 06z ensemble lows...slightly deeper and maybe slightly closer but still southeastward to the BM. Insignificant change? Attached: GGEM op 06z version qpf in MM for snow/sleet/rain. Continues to look promising but with the EPS uncertainty. GEM op by 1P Monday nearly a foot vicinity ABE.
  10. wdrag
    Added a statement from WPC this morning:
  11. wdrag
    No modeling insights: Drew my conclusions from modeling consensus. Patience needed. 554AM Friday 1/29: 00z06z/29 GEFS/00z/29 GEPS are the heavies including 00z-06z/29 V16 and now the 00z/29 UKMET. Yikes? Where is the EPS? SO... big snowstorm potential but rather than overcommit, especially since WPC followed the EPS downgrade fairly close. Still 3 days away. Watch the NAM trends... this is it's game, imo. NOT much change from previous due to still variable model solutions. Left rain in for LI and I95 sewd sometime Monday afternoon-early Tue?; changed ice to ice pellets, and held onto wind event which would probably be restricted to the coasts. Added coastal flooding: too long a duration of gale force ne winds acting upon an astronomically normal tide will result in a substantial surge. Coastal flooding could be multiple high tide cycles beginning midday Monday through midday Tuesday and current outlooks are for the greatest threat with the midnight Monday night high tide cycle. Minor coastal flooding seems probable for one of the high tide cycles, but moderate not out of the question. Stay tuned to NWS products as we draw closer Timing UNCERTAIN: Held the 31st for the start in our forum, but probably restricted to PA/NJ/LI, with the heaviest snow there slated for sometime Monday before a possible dry slot changes to mixed pcpn parts of the I95 corridor?. The I84 region may have to wait til sunrise Monday and I90 possibly til Monday afternoon?? Not worried about the ending yet, since first it has to start, but probably bands circling south and southeastward through at least part of Tuesday. EPS/EC 12z/28 and 00z/289 surprisingly southeast of multiple op's and ensembles. WPC overnight responded southeastward. The upcoming planned March implementation of the GFS v16 was quite robust again on the 00z and a bit less so on the 06z/29 cycle so rather than shift too far south and have to go back north, am holding onto a widespread snowstorm. Best axis: ? unknown. Long duration, especially NJ/PA. There could be heavy snow in the comma head deformation zone north of modeled qpf, but far too early to find consensus on the comma head, due to modeling differences. Not a major concern but monitoring for WET 32-33F snow near the coasts... not going into this any further till we have consensus on temps/amounts.
  12. wdrag
    fwiw: coms problems somewhere. Some of the WPC probabilistic and D4-7 not displaying properly and the GFS 06z V16 is running a tad late.
  13. wdrag
    Regionalize. If it stands out... it's no good if a loner and a typo. Thanks, Walt
  14. wdrag
    More messenger: NWS is tightening the collaboration with CPC. Note the changes ne USA issued around 3P. Suspect the story headline changes tomorrow afternoon from W coast to the eastern USA, so NJ-PA-MD-VA's EM not surprised Monday morning, going home for the weekend. OKX has had 6" in its HWO since early this morning, which i think a good move. PHI has gone to the enhanced HWO color coded...not good imo in that it won't flag snow potential beyond 72 hours. However, it is what the NWS is gravitating to so that leaves forums/private sector available to attempt to fill the gap. They do have one graphic out: It's recently added since 3P and attached. No EM briefing package yet, nor do I expect today.
  15. wdrag
    I have no answers... just a messenger... 12z/28 NAEFS slightly slower which fits the ensembles you've seen. Just as cold but with BL temp problems LI-PHL. NAEFS is a good look for the I95s corridor PHL-BOS with the usual I95 sewd uncertainty.
  16. wdrag
    Did you see my just 10 min ago post. It's posted..rudimentary. Sometimes, if the model misses a vendor call window, it may not get caught up til later. Think there have been some internet problems on the east coast late this morning. No factual info.
  17. wdrag
    Yes... 26th my burn. Love the interest by everyone and keeping everyone up to speed. Definitely of interest.
  18. wdrag
    WPC keeps stats as does NHC, in season... I don't know the answer. Think the general consensus is EC/EPS best and tends to be conservative on qpf. GFS clearly a more convective model than the EC and a high bias on qpf, tho suspect if it flags big... need to take an extra look. Sometimes it's fantastic...many others... secondary to other models. GGEM- I like it. Many do not. I do know this winter tells the truth on all these threads. IF the GGEM doesn't have it big, forget it! Time after time. Folks can look back. Doesn't mean that the GGEM is more accurate areally & placement but does mean it garners, at least my respect. Models evolve and so results may not be valid 2 years from now. If models were static as back in the 60s/70s... then your proposal would be more useful. There may be others that can provide more info... i do agree, 500MB does not do it for me. I don;'t get a chance to view many WPC qpf/extended discussions but they may tuck some info in there. Was good that someone posted the EFP discussion from WPC earlier this morning. Thank you.
  19. wdrag
    Hi everyone, Despite the stark southward shift-shrift of the 12z/28 EPS, the 12z/28 GFSv16 op (seen previously I think) and GGEM op continue on course with WPC's 16z qpf...if not heavier. Attached the 12z/28 EPS (last) and the 12Z GGEM panels and 240 hour snowfall in MM. 25MM=1" (reds). BIG but only an op. Its' mostly rain or ice for 2/5ish so that is not a snowfall contributor. The good news...GGEM still on board. Whether that's right or wrong??????? What this all tells me... wait on commitment north-south or in between. My gut tells me more northwest but that's not science. It could be as one poster ID wish casting. Need to wait it out. There is lots of interactive sensitivity that will take a few more cycles to convince us one way or the other.
  20. wdrag
    You're right... I used to pay more attention to this model and it's global stat ranking but over the last year that I've tried to use this...much more miss than hit. just another member of the 12z cycle, serving as downside reminder for those who want snow near 40N. Would like to see UK ensemble but have no source.
  21. wdrag
    Is i not the trend of GFS to virtually always be too far south on these ne storms at days 3 and beyond? If it doesn't close off, then it's close now, but if it closes off, then I expect a northward drift to the GFS solutions.
  22. wdrag
    Internet slow here in nw NJ. Another WPC placeholder till we all can fully evaluate all the modeling. This is the 12z/28 WPC D4-8, may be difficult to view? It's not yet updated on normal displays there, but my interp...they are going more and more in, certainly more likely than the 00z/28 stat version off D4-8.
  23. wdrag
    Anyway, thought some of us might like this as a placeholder. 1553z/28 WPC D4-5 Hope it's right for all of us. Still plenty of variability.
  24. wdrag
    As a placeholder, thought you'd like to see this from WPC D4-5s. AGREED 100% Don..this for my forecaster friends in New England and elsewhere who doubt. At least one or two others have noticed. I've no answers, except to hold onto ensembles/WPC and then use your own judgement. Just have to hang on ...all those EPS's posted earlier... they could be wrong, but it would imo be a formidable EPS bust on the axis of max snowfall. (note not amount but axis). This whole system has above normal SST's off NJ/DE. That may aid development? Later, Walt
  25. wdrag
    V16 and GGEM are now slowly posting.
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