WxMan1 Posted January 15, 2013 Share Posted January 15, 2013 Has something changed at the HPC in the way they arrive at winter weather forecasts? They've been strangely aggressive this season so far. Like, what's up with this really high probability of more than a trace of freezing rain for the area? gymengineer, These values are generated based from HPC's "autoensemble", which is a 28 member ensemble that includes operational model runs as well as 21 SREF members...while the "mode" is the actually deterministic snow/ice forecast based from the HPC winter weather forecaster. I have too noticed that at times this autoensemble is a bit robust when it comes to the ice accumulation threat, especially with the lower thresholds. I think part of that's a function of being correlated with the high resolution SREF ARW and NMMB members. At any rate, while these autoensemble probabilities are unedited, the HPC winter weather forecaster does have the final call on the 10, 40, and 70% probabilities of the 4, 8, and 12" snowfall amounts as well as 0.25" ice amounts. A bit confusing probably, but this link will probably provide more clarity: http://origin.hpc.ncep.noaa.gov/pwpf/about_pwpf_products.shtml Link to comment Share on other sites More sharing options...
Bob Chill Posted January 15, 2013 Share Posted January 15, 2013 Once we get past this weekend (at the very least) it looks like any precip would be frozen. Models are mostly dry but there is plenty of room for a ns system to get below us. Especially after the gl low gets out of the way and the trough digs deep. Polar 500 loop on the last 2 runs of the gfs shows a pretty fast flow with some energy coming out of west central canada from time to time. It's going to be tough until the depth and axis of the eastern trough sets up more favorably. Early on the storm track is still to the north but things amplify by hr 150 or so. There is a big closed 500 low in the pac between baja and hawaii. It does drift towards mexico through time. PIeces will eject from this from time to time. Not an ideal placement for getting some sort of split flow phase type of scecnario but it's not a bad thing having that feature in the pac either. No signs of anything coming through the the sw anytime soon. Not that anything was expected though. The big ridge of HP in the west is quite the wall for any kind of system to hit the CA coast. IMO- there are only 2 options going forward for now. Having a juicy clipper take a good track once the trough deepens and the axis sets up in a better spot or some sort of phase from ns energy coming out of canada meeting up with a piece that gets ejected from the closed low in the pac. Otherwise we sit and wait until the closed low in the pac traverses mexico and hope we still have an amplified pattern at the time. All in all it looks cold with precip falling as snow if there is any precip in the area. Going to be tough for anything moisture laden to get here for a while. And things will change 100 times between now and next weekend anyway. I took some time this morning too look at the nh circ in the lr and this is what I'm seeing fwiw. Link to comment Share on other sites More sharing options...
Midlo Snow Maker Posted January 15, 2013 Author Share Posted January 15, 2013 gfs coming in much further north with the precip this run Link to comment Share on other sites More sharing options...
Ian Posted January 15, 2013 Share Posted January 15, 2013 im jogging up for the punt Link to comment Share on other sites More sharing options...
Deck Pic Posted January 15, 2013 Share Posted January 15, 2013 im jogging up for the punt lol..you haven't punted yet?.. Link to comment Share on other sites More sharing options...
Ian Posted January 15, 2013 Share Posted January 15, 2013 lol..you haven't punted yet?..my thoughts are littered above.. i mean, i wasnt really expecting anything but what else is there except wretched cold to talk about Link to comment Share on other sites More sharing options...
nflwxman Posted January 15, 2013 Share Posted January 15, 2013 This is generally when we see the GFS starting to correct north. However, it won't look like the train wreck NAM. I'm not sure it will help out DC, but RIC and maybe EZF could get in the light snow action. Link to comment Share on other sites More sharing options...
mitchnick Posted January 15, 2013 Share Posted January 15, 2013 my thoughts are littered above.. i mean, i wasnt really expecting anything but what else is there except wretched cold to talk about long range just looks bleh with cold and dry pattern Link to comment Share on other sites More sharing options...
clueless Posted January 15, 2013 Share Posted January 15, 2013 long range just looks bleh with cold and dry pattern I am hoping this changes in the next day or two. Ahem. Better yet run or two. Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted January 15, 2013 Share Posted January 15, 2013 Accuwx shows my coldest day as being next Wed with a high of 31F. Really? All this talk and tracking of the arctic air mass and the coldest air is 31F? Still a week away, and it's Accuwx, I guess. Link to comment Share on other sites More sharing options...
Ian Posted January 15, 2013 Share Posted January 15, 2013 Accuwx shows my coldest day as being next Wed with a high of 31F. Really? All this talk and tracking of the arctic air mass and the coldest air is 31F? Still a week away, and it's Accuwx, I guess.leesburg04 has had about the best record of anyone this year.. i'd seek out his thoughts Link to comment Share on other sites More sharing options...
mitchnick Posted January 15, 2013 Share Posted January 15, 2013 I am hoping this changes in the next day or two. generally speaking, that has pretty much been showing up on all the mr and lr models I now use the CFS2 to see if it has a lousy forecast for us because they always verify and the good ones don't FEB temp forecast is incredibly cold and the precip forecast is as dry as you can get http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/usT2mMonInd1.gif http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/usPrecMonInd1.gif thus I feel confident in saying that by March 1 those who wanted cold regardless of snowfall will have had it Link to comment Share on other sites More sharing options...
MN Transplant Posted January 15, 2013 Share Posted January 15, 2013 DC jackpot! Link to comment Share on other sites More sharing options...
mitchnick Posted January 15, 2013 Share Posted January 15, 2013 anyone else using NCEP stuck at 111 hrs? Link to comment Share on other sites More sharing options...
yoda Posted January 15, 2013 Share Posted January 15, 2013 ^ 20:1 ratios! Link to comment Share on other sites More sharing options...
Bob Chill Posted January 15, 2013 Share Posted January 15, 2013 Accuwx shows my coldest day as being next Wed with a high of 31F. Really? All this talk and tracking of the arctic air mass and the coldest air is 31F? Still a week away, and it's Accuwx, I guess. Accuwx just has automated output so their forecast past 5 days or so change like every 3 hours. I personally don't expect the coldest of the airmass to hit us until next weekend. It looks like it takes 5-6 days to start the real amplification process for the trough to dig deep. There will likely be a series of reinforcing shots after the gl lows crosses to our north next week. I personally think this cold shot is going to be impressive overall. Prob have to go back to 2005 or earlier to beat it. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 15, 2013 Share Posted January 15, 2013 DC jackpot! USA_PCPPRSTMP_850mb_162.gif if we can get any kind of pulse during that stretch we could get an inch out of very little liquid Link to comment Share on other sites More sharing options...
Deck Pic Posted January 15, 2013 Share Posted January 15, 2013 Accuwx shows my coldest day as being next Wed with a high of 31F. Really? All this talk and tracking of the arctic air mass and the coldest air is 31F? Still a week away, and it's Accuwx, I guess. why would you use some accuweather automated output for over a week from now?...do you even read this forum? Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 15, 2013 Share Posted January 15, 2013 I am hoping this changes in the next day or two. Ahem. Better yet run or two. Given the way its going, it will...............to a dry and much less cold look. Link to comment Share on other sites More sharing options...
clueless Posted January 15, 2013 Share Posted January 15, 2013 generally speaking, that has pretty much been showing up on all the mr and lr models I now use the CFS2 to see if it has a lousy forecast for us because they always verify and the good ones don't FEB temp forecast is incredibly cold and the precip forecast is as dry as you can get http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/usT2mMonInd1.gif http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/usPrecMonInd1.gif thus I feel confident in saying that by March 1 those who wanted cold regardless of snowfall will have had it Generally speaking any lousy forecast verifies. Rule of thumb regardless of the merit of any particular model. We are so easy... Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 15, 2013 Share Posted January 15, 2013 anyone else using NCEP stuck at 111 hrs? Getting ready to explode again? Link to comment Share on other sites More sharing options...
Bob Chill Posted January 15, 2013 Share Posted January 15, 2013 if we can get any kind of pulse during that stretch we could get an inch out of very little liquid I think we'll get a couple light qpf shots during the cold stretch. Spokes and vorts are likely and models won't pick up on those for a week. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 15, 2013 Share Posted January 15, 2013 GFS has maxes in the low 20s for next Tuesday and Wednesday...that is not too shabby if it comes to fruition...even a day with highs of 23-27 would be impressive Link to comment Share on other sites More sharing options...
Deck Pic Posted January 15, 2013 Share Posted January 15, 2013 I think we'll get a couple light qpf shots during the cold stretch. Spokes and vorts are likely and models won't pick up on those for a week. we did during the 2009 outbreak...light snow/flurries a few times..we had a T 6 times that month Link to comment Share on other sites More sharing options...
Bob Chill Posted January 15, 2013 Share Posted January 15, 2013 Doubt the gfs is right but the setup at 5h in the lr is a bit attractive. Active feed of pac energy into BC and nice trajectory downstream. We could get n-streamed to death. We'll make a dent 1" at a time. lol Link to comment Share on other sites More sharing options...
clskinsfan Posted January 15, 2013 Share Posted January 15, 2013 Given the way its going, it will...............to a dry and much less cold look. I am pretty confident the cold is coming. But I'm afraid the dry is coming with it. Once the cold starts to relax we may have a shot. And the models have hinted at something like that in the long range. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 15, 2013 Share Posted January 15, 2013 Doubt the gfs is right but the setup at 5h in the lr is a bit attractive. Active feed of pac energy into BC and nice trajectory downstream. We could get n-streamed to death. We'll make a dent 1" at a time. lol I imagine we'll get at least 1-2 events where the vort goes through PA and we get glorified cartoppers or maybe even an inch Link to comment Share on other sites More sharing options...
WVclimo Posted January 15, 2013 Share Posted January 15, 2013 12Z GFS finally starting to show some QPF from the fetch off the Lakes most of next week. Been waiting to see that, as you'd expect that with a NW flow of arctic air. Link to comment Share on other sites More sharing options...
Bob Chill Posted January 15, 2013 Share Posted January 15, 2013 I am pretty confident the cold is coming. But I'm afraid the dry is coming with it. Once the cold starts to relax we may have a shot. And the models have hinted at something like that in the long range. I think we can be confident that the dry is coming too. No signs of split flow / ss interaction. I agree with zwyts with one exception. We get at least one vort passing through central VA. GFS has that look at least. I'll gladly take an ice cold 1-3 / 2-4 over a melt in a day 4-6 slopfest. Link to comment Share on other sites More sharing options...
Kmlwx Posted January 15, 2013 Share Posted January 15, 2013 Doubt the gfs is right but the setup at 5h in the lr is a bit attractive. Active feed of pac energy into BC and nice trajectory downstream. We could get n-streamed to death. We'll make a dent 1" at a time. lol Meh. I don't want little quarter sized hail dents. I want this kind of dent Link to comment Share on other sites More sharing options...
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