wxmeddler Posted October 28, 2011 Share Posted October 28, 2011 November 6-7, 1953: (only 9 days off!) This is the earliest recorded major snowfall (4 or more inches) with 5.9 inches recorded in Baltimore. From our weather records here at Millersville 17" in York, PA and 13.5 in Lancaster Some guy on a mountain top outside of Harrisburg got 30". So Its is possible!... but not likely.. Link to comment Share on other sites More sharing options...
stormtracker Posted October 28, 2011 Author Share Posted October 28, 2011 NAM much warmer it looks at initialization. Enjoy your 5post status. Use them wisely. Link to comment Share on other sites More sharing options...
usedtobe Posted October 28, 2011 Share Posted October 28, 2011 Looks like the 09z SREFs takes the h5 vort in to S VA at hr 36 and 39 That would be a decent track. Link to comment Share on other sites More sharing options...
MN Transplant Posted October 28, 2011 Share Posted October 28, 2011 Looks like the 09z SREFs takes the h5 vort in to S VA at hr 36 and 39 which would be beneficial for us I believe 850 line just parks itself over DC from 12z to 18z. Link to comment Share on other sites More sharing options...
chris87 Posted October 28, 2011 Share Posted October 28, 2011 850 line just parks itself over DC from 12z to 18z. 850 line is worthless in an ensemble mean though...need to make sure you don't have any warm/cold members causing bias Link to comment Share on other sites More sharing options...
MN Transplant Posted October 28, 2011 Share Posted October 28, 2011 850 line is worthless in an ensemble mean though...need to make sure you don't have any warm/cold members causing bias Yes, true, the perils of an ensemble . Link to comment Share on other sites More sharing options...
chris87 Posted October 28, 2011 Share Posted October 28, 2011 Yes, true, the perils of an ensemble . true, thanks for posting, that's a lot of rainy members Link to comment Share on other sites More sharing options...
yoda Posted October 28, 2011 Share Posted October 28, 2011 I think I counted 11 of the 19 members being in favor of the 850 0c line being over or east of us on the SREF map posted above at 18z Link to comment Share on other sites More sharing options...
yoda Posted October 28, 2011 Share Posted October 28, 2011 Comparing the 1000-500 thickness maps from the 12z at hr 21 and the 06z at hr 27, it would appear that the NAM is coming in a lil bit warmer (but not by much at all). Link to comment Share on other sites More sharing options...
clskinsfan Posted October 28, 2011 Share Posted October 28, 2011 I am stunned that I am tracking a potential 3-6 storm this early in the season. Those of us to the west have a little elevation on our side. But I will believe 3-6 when I see it. A dusting in October? OK. I am down with that. Link to comment Share on other sites More sharing options...
MN Transplant Posted October 28, 2011 Share Posted October 28, 2011 Following along on instantweathermaps.com Through 24hrs (12z), the R/S line in SW to NE through the inner NW DC suburbs. 850s are fine, maybe even -2 at DCA, even at 950 we seem to be below freezing. Link to comment Share on other sites More sharing options...
chris87 Posted October 28, 2011 Share Posted October 28, 2011 12z NAM was a bit warmer in the earlier periods in the low levels but DCA to BWI never get above -2C at 850 hPa and by 12z things are close to changing over Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted October 28, 2011 Share Posted October 28, 2011 I really don't know if anyone, especially the mets, put any faith in these maps, but I try to see trends in them. FWIW, heres the new probs map. Edit: BTW, this is better, but it is still a razor edge for the DC-Balt corridor Link to comment Share on other sites More sharing options...
MN Transplant Posted October 28, 2011 Share Posted October 28, 2011 850 location Link to comment Share on other sites More sharing options...
yoda Posted October 28, 2011 Share Posted October 28, 2011 12z NAM seems to be producing more QPF on this run in South Central VA than on the 06z run... or is that the expanse of the QPF field being larger at hr 24? Link to comment Share on other sites More sharing options...
eurojosh Posted October 28, 2011 Share Posted October 28, 2011 I really don't know if anyone, especially the mets, put any faith in these maps, but I try to see trends in them. FWIW, heres the new probs map. I think the key feature of all these maps - whether operational models or probability maps - is the sharp cutoff close to I-95. Based on this, I think it's relatively safe to make forecasts for, say, Winchester VA or Hagerstown MD at this point, the problem is just that a couple of degrees difference could make all the difference in DC/Balt when it comes to bust - and the distance between boom and bust is within the model margins of error. Rather than trying to pin down a number, can't we just leave it at 'slight chance of accumulating snow for I-95 areas, with accumulation likelihood and potential increasing to the west and north'? Link to comment Share on other sites More sharing options...
MN Transplant Posted October 28, 2011 Share Posted October 28, 2011 Closest the 850 line gets to DC is around 16z, looks like it is turning after that. By 18z-19z it is snowing in DC. Link to comment Share on other sites More sharing options...
yoda Posted October 28, 2011 Share Posted October 28, 2011 h5 vort very strong entering SW VA at hr 27 -- http://mag.ncep.noaa...500_vort_ht.gif At 30 -- http://mag.ncep.noaa...500_vort_ht.gif Looks like its going to go through South Central VA over RIC Link to comment Share on other sites More sharing options...
chris87 Posted October 28, 2011 Share Posted October 28, 2011 Closest the 850 line gets to DC is around 16z, looks like it is turning after that. By 18z-19z it is snowing in DC. Agreed, takes a bit longer to change over than the 6z, but seems to be in line with the ECMWF....great deformation band.... Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted October 28, 2011 Share Posted October 28, 2011 I think the key feature of all these maps - whether operational models or probability maps - is the sharp cutoff close to I-95. Based on this, I think it's relatively safe to make forecasts for, say, Winchester VA or Hagerstown MD at this point, the problem is just that a couple of degrees difference could make all the difference in DC/Balt when it comes to bust - and the distance between boom and bust is within the model margins of error. Rather than trying to pin down a number, can't we just leave it at 'slight chance of accumulating snow for I-95 areas, with accumulation likelihood and potential increasing to the west and north'? I think you've stated the reason that this is probably a forecasting nightmare for the areas in and around DC. The forecasters face the wrath of an angry public with either forecast (provided its wrong). I do not envy those guys their jobs on this one. Link to comment Share on other sites More sharing options...
TalcottWx Posted October 28, 2011 Share Posted October 28, 2011 Agreed, takes a bit longer to change over than the 6z, but seems to be in line with the ECMWF....great deformation band.... Music to the ears of those wishing for snow in the 95 corridor and just NW of the interstate... Link to comment Share on other sites More sharing options...
MN Transplant Posted October 28, 2011 Share Posted October 28, 2011 Enough with standard atmospheric analysis, here's the clown map Link to comment Share on other sites More sharing options...
chris87 Posted October 28, 2011 Share Posted October 28, 2011 I think you've stated the reason that this is probably a forecasting nightmare for the areas in and around DC. The forecasters face the wrath of an angry public with either forecast (provided its wrong). I do not envy those guys their jobs on this one. This forecast can make the best look really dumb..i don't envy anyone in that position today...we're talking gradients that even a 12 km mesoscale model like the NAM shouldn't' be expected to be entirely correct. Link to comment Share on other sites More sharing options...
chris87 Posted October 28, 2011 Share Posted October 28, 2011 the changeover in the I-95 corridor is actually delayed this run by a warm layer around 700 hPa....the low level temps (850 and below) support changeover closer to 12z... Link to comment Share on other sites More sharing options...
stormtracker Posted October 28, 2011 Author Share Posted October 28, 2011 h5 vort very strong entering SW VA at hr 27 -- http://mag.ncep.noaa...500_vort_ht.gif At 30 -- http://mag.ncep.noaa...500_vort_ht.gif Looks like its going to go through South Central VA over RIC Wes should like this. N and W still look to be the place to be, but even DCA gets in on the fun Link to comment Share on other sites More sharing options...
yoda Posted October 28, 2011 Share Posted October 28, 2011 This forecast can make the best look really dumb..i don't envy anyone in that position today...we're talking gradients that even a 12 km mesoscale model like the NAM shouldn't' be expected to be entirely correct. I don't envy the forecasters at all... DC could get nothing to rain to at the most extreme close to warning criteria snows... Link to comment Share on other sites More sharing options...
usedtobe Posted October 28, 2011 Share Posted October 28, 2011 Closest the 850 line gets to DC is around 16z, looks like it is turning after that. By 18z-19z it is snowing in DC. That's later then the 06Z run. Link to comment Share on other sites More sharing options...
yoda Posted October 28, 2011 Share Posted October 28, 2011 h7 fields show -15 UVVs hrs 27 and 30 acorss the LWX area Link to comment Share on other sites More sharing options...
TalcottWx Posted October 28, 2011 Share Posted October 28, 2011 Enough with standard atmospheric analysis, here's the clown map Thought would be more in Metro Link to comment Share on other sites More sharing options...
eurojosh Posted October 28, 2011 Share Posted October 28, 2011 This forecast can make the best look really dumb..i don't envy anyone in that position today...we're talking gradients that even a 12 km mesoscale model like the NAM shouldn't' be expected to be entirely correct. Delete this if it's storm-mode-necessary, but this all sounds like an argument for improving the teaching of statistics and probability in our high schools... there should be a Union of Concerned Meterologists pushing this stuff or something. It would lead to massive productivity savings over a lifetime if people understood probability better (especially low probability/high impact) based on reaction to weather alone... Link to comment Share on other sites More sharing options...
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