HM Posted March 3, 2013 Share Posted March 3, 2013 HM, are you talking about the s/w at hr 96 on the euro? I think at the point the damage is done and it doesn't matter much. I don't think so. Its influence of adding momentum on the backside is going on long before and it prevents it from going more negatively tilted along the coast. I know it is subtle but it makes a difference for DC-PHL corridor. The differences between the GFS and ECMWF with the Atlantic Low right now are also ridiculous. Link to comment Share on other sites More sharing options...
EasternUSWX Posted March 3, 2013 Share Posted March 3, 2013 Those HPC probabilities are determined by the GFS. Can't be. GFS doesn't give southern PA enough GFS for anywhere close to 18" Link to comment Share on other sites More sharing options...
lester Posted March 3, 2013 Share Posted March 3, 2013 Jim Cantore has been dispatched....... Hopefully it's not in DC, then it'll really go south and east and miss us Link to comment Share on other sites More sharing options...
swimmatte Posted March 3, 2013 Share Posted March 3, 2013 Those HPC probabilities are determined by the GFS. We go over this every time...... it's computer generated based on SREF's plus the rest of the model runs. Link to comment Share on other sites More sharing options...
Ian Posted March 3, 2013 Share Posted March 3, 2013 Jim Cantore has been dispatched....... Where? He mentioned DC last night. Hopefully he means west of town for his sake. Last place id go at this pt is the Mall. Link to comment Share on other sites More sharing options...
BristowWx Posted March 3, 2013 Share Posted March 3, 2013 Jim Cantore has been dispatched....... Oh no...where is he headed? Downtown DC? Link to comment Share on other sites More sharing options...
winter_warlock Posted March 3, 2013 Share Posted March 3, 2013 I don't think so. Its influence of adding momentum on the backside is going on long before and it prevents it from going more negatively tilted along the coast. I know it is subtle but it makes a difference for DC-PHL corridor. The differences between the GFS and ECMWF with the Atlantic Low right now are also ridiculous. SO basically its who do you trust, gfs or euro Link to comment Share on other sites More sharing options...
swimmatte Posted March 3, 2013 Share Posted March 3, 2013 That graphic uses the following: 21 NCEP Short-Range Ensemble Forecast (SREF) members 1 NCEP North American Mesoscale (NAM) 12Z (day) or 00Z (night) operational run1 NCEP Global Forecast System (GFS) 12Z (day) or 00Z (night) operational run1 European Center for Medium-Range Weather Forecasts (ECMWF) latest operational run1 Canadian Model (CMC) latest operational run1 ECMWF latest ensemble mean1 NCEP Global Ensemble Forecast System (GEFS) latest ensemble mean (6-h SLRs)1 GEFS latest ensemble mean (24-h mean SLR) Link to comment Share on other sites More sharing options...
WxMan1 Posted March 3, 2013 Share Posted March 3, 2013 Those HPC probabilities are determined by the GFS. Incorrect. GFS is one out of the 28 members. http://www.hpc.ncep.noaa.gov/pwpf/about_pwpf_products.shtml Link to comment Share on other sites More sharing options...
HM Posted March 3, 2013 Share Posted March 3, 2013 Well, this is the sort of unbiased analysis we need. HM, I think you are discussing an elongated vorticity complex that is vertically oriented just a bit north of the Great Lakes. It appears muted and weak on the GFS and much more intense on the EURO. How soon will we know which is correct? I'm hoping the EURO ensembles shed some light. I think if the ECMWF keeps this up on tonight's run and we see the other data start trending that way, then I would keep expectations in check on the northern edge of this thing. The good news is that these situations are so bad in the modeling (waves underneath blocking...subtle features etc.) that this can easily be taken away on the 00z runs. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 3, 2013 Share Posted March 3, 2013 I don't think so. Its influence of adding momentum on the backside is going on long before and it prevents it from going more negatively tilted along the coast. I know it is subtle but it makes a difference for DC-PHL corridor. The differences between the GFS and ECMWF with the Atlantic Low right now are also ridiculous. I don't know..looks pretty far separated still when the ULL exits off of HSE. I do agree right after it helps give it a boot..but I'm not sure if it's that big of a deal quite yet. Link to comment Share on other sites More sharing options...
mitchnick Posted March 3, 2013 Share Posted March 3, 2013 87 hr from the new SREF looks the same as last run http://mag.ncep.noaa.gov/Image.php?model=sref&area=namer¶m=500_vort_ht&cycle=15ℑ=sref%2F15%2Fsref_namer_087_500_vort_ht.gif Link to comment Share on other sites More sharing options...
CoastalWx Posted March 3, 2013 Share Posted March 3, 2013 Regardless, the euro op just seems to occlude too fast which can happen...it did it in the Feb blizzard we had as well. Link to comment Share on other sites More sharing options...
mitchnick Posted March 3, 2013 Share Posted March 3, 2013 87 hr from the new SREF looks the same as last run http://mag.ncep.noaa.gov/Image.php?model=sref&area=namer¶m=500_vort_ht&cycle=15ℑ=sref%2F15%2Fsref_namer_087_500_vort_ht.gif better actually 24 hr precip at 87 hrs http://mag.ncep.noaa.gov/Image.php?model=sref&area=namer¶m=precip_p24&cycle=15ℑ=sref%2F15%2Fsref_namer_087_precip_p24.gif Link to comment Share on other sites More sharing options...
HM Posted March 3, 2013 Share Posted March 3, 2013 The ECMWF doesn't have a stretched out Atlantic Low setup at Day 3 where the GFS does. This is having an effect on negatively titled timing too. These subtle differences can easily change in the coming days. Link to comment Share on other sites More sharing options...
MN Transplant Posted March 3, 2013 Share Posted March 3, 2013 I don't think so. Its influence of adding momentum on the backside is going on long before and it prevents it from going more negatively tilted along the coast. I know it is subtle but it makes a difference for DC-PHL corridor. The differences between the GFS and ECMWF with the Atlantic Low right now are also ridiculous. Very good point. The Nova Scotia low in the GFS gets dismantled between our storm and the big low dropping from E of Greenland. On the ECMWF it is still acting as its own entity longer, likely affecting the path of our low. Link to comment Share on other sites More sharing options...
EasternUSWX Posted March 3, 2013 Share Posted March 3, 2013 SREF still not budging. If anything it is north this run. Link to comment Share on other sites More sharing options...
PhineasC Posted March 3, 2013 Share Posted March 3, 2013 better actually 24 hr precip at 87 hrs http://mag.ncep.noaa.gov/Image.php?model=sref&area=namer¶m=precip_p24&cycle=15ℑ=sref%2F15%2Fsref_namer_087_precip_p24.gif The SREFs are going total ape mode now. Link to comment Share on other sites More sharing options...
NOVAForecaster Posted March 3, 2013 Share Posted March 3, 2013 I think this is one of the most important maps from the HPC. >50% chance of more than 8" for the northwest suburbs, and 40% chance downtown and just southeast. Th think the number DC hould be focusing on at this point for possible totals is 6"-10". Link to comment Share on other sites More sharing options...
mitchnick Posted March 3, 2013 Share Posted March 3, 2013 The SREFs are going total ape mode now. I saw that 1' qpf during the 24 hrs ending 87 hrs and nearly needed a nitro Link to comment Share on other sites More sharing options...
HM Posted March 3, 2013 Share Posted March 3, 2013 I don't know..looks pretty far separated still when the ULL exits off of HSE. I do agree right after it helps give it a boot..but I'm not sure if it's that big of a deal quite yet. The blocking takes on an "omega" look between that wave, the Atlantic Low and the Quebec Ridge. The less influence from the back-end wave would increase ridging out West and diminish the increasing momentum of this thing diving down under the block. I think these small differences can have an effect on the negative tilt timing and therefore its subsequent occluding process. I guess we will found out. Good talk... Link to comment Share on other sites More sharing options...
EasternUSWX Posted March 3, 2013 Share Posted March 3, 2013 Regardless, the euro op just seems to occlude too fast which can happen...it did it in the Feb blizzard we had as well. You mean the model occluded too fast compared to actual or it seemed like it was modeled to occlude too fast but, that was the actual result? Link to comment Share on other sites More sharing options...
vinylfreak89 Posted March 3, 2013 Share Posted March 3, 2013 I don't know..looks pretty far separated still when the ULL exits off of HSE. I do agree right after it helps give it a boot..but I'm not sure if it's that big of a deal quite yet. from what I see on WunderMaps (great btw, never knew those existed before) because it is so far upstream from the ULL, the jet is oriented in such a way it becomes a kicker, and increases the forward momentum of the bowling ball. Link to comment Share on other sites More sharing options...
PhineasC Posted March 3, 2013 Share Posted March 3, 2013 Who cares if the probability maps are computer-generated? The model runs themselves are computer-generated. It is just another product to look at. Link to comment Share on other sites More sharing options...
yoda Posted March 3, 2013 Share Posted March 3, 2013 I saw that 1' qpf during the 24 hrs ending 87 hrs and nearly needed a nitro The 1" shows up at 72 on the 24hr QPF as well fyi Link to comment Share on other sites More sharing options...
WxMan1 Posted March 3, 2013 Share Posted March 3, 2013 Regardless, the euro op just seems to occlude too fast which can happen...it did it in the Feb blizzard we had as well. Yes, and the fact that the operational EC has been on the outer (southern) fringes of it's 50 member ensemble spread with the low track, now within 96 hours, has to be a concern. Certainly wouldn't toss out the op EC, but I also wouldn't put as much weight into that deterministic run. Certainly not as much as the GFS and GEFS/SREF means at this point, which are locked in, and compare more favorably with the EC mean than the op EC does. Link to comment Share on other sites More sharing options...
vinylfreak89 Posted March 3, 2013 Share Posted March 3, 2013 Yes, and the fact that the operational EC has been on the outer (southern) fringes of it's 50 member ensemble spread with the low track, now within 96 hours, has to be a concern. Certainly wouldn't toss out the op EC, but I also wouldn't put as much weight into that deterministic run. Certainly not as much as the GFS and GEFS/SREF means at this point, which are locked in, and compare more favorably with the EC mean than the op EC does. Adding to your point, I think its pretty rare for the OP to be on its own and to have been right. Anyone know any notable examples (either good or bad for us)? Link to comment Share on other sites More sharing options...
nflwxman Posted March 3, 2013 Share Posted March 3, 2013 Yes, and the fact that the operational EC has been on the outer (southern) fringes of it's 50 member ensemble spread with the low track, now within 96 hours, has to be a concern. Certainly wouldn't toss out the op EC, but I also wouldn't put as much weight into that deterministic run. Certainly not as much as the GFS and GEFS/SREF means at this point, which are locked in, and compare more favorably with the EC mean than the op EC does. The GFS is locked in? 12 hours ago it was showing the heaviest axis of snow 75-100 miles South. Link to comment Share on other sites More sharing options...
Ian Posted March 3, 2013 Share Posted March 3, 2013 Who cares if the probability maps are computer-generated? The model runs themselves are computer-generated. It is just another product to look at. Still worth noting as the other product is done by hand. Link to comment Share on other sites More sharing options...
mitchnick Posted March 3, 2013 Share Posted March 3, 2013 Adding to your point, I think its pretty rare for the OP to be on its own and to have been right. Anyone know any notable examples (either good or bad for us)? I just remember it was very south with the 12/09 bliz and joined the party last sometimes it's fickle and wrong once we're within 48 hrs, it'll join the party Link to comment Share on other sites More sharing options...
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