12Z NAM fantasy; No thanks I wont Bite ; Review of my Midwest snowstorm forecast 11/29

Taking a look at the Midwest Big snowstorm... my prediction made Wed afternoon 243 pm EST.... "12z WED models support the Big Midwest Low/ snow WHAT ABOIUT 1ST SECS 12/4-5???" .... said this

6'' seem likely could be more ( up to 12 inches) but for one its warm now and transitioning to cold and the ground will be wet.... Big winners QUINCY ILL along with GALESBURG ILL JACKSONSVILLE ILL PEORIA ILL into DeKALB JOILET and maybe Chicago

I do aplogize to my Midwest fans who wnated to see my snowstorms maps broken out for this event. if I had the time I would of m,ap some maps in the 3 tier systems that I have nbeen usiong since 1999...2000.... 1st guess 1st call Last call


Well be 12z FRI NAM has an interesting solution for Monday recording the possible development of a coastal low over eastern NC and of course seeing this development causes a reaction by some within the meteorological community.

While it is true that the 12z NAM develops this wave of Low-pressure significantly closer to the coast so that it actually produces precipitation from eastern Virginia up into New York City coastal New Jersey Long Island and southern New England on Monday... there are some serious problems with this scenario and these problems are more than sufficient to cause me to look at the fantasy of 12 z NAM solution as well just that... a fantasy.

To be sure this trough is neutrally tilted by the time and reaches the Mississippi River and appears to develop or take on a slightly native tilt by Monday morning as it moves through the Tennessee Valley and the Appalachians. This shift in the trough axis from neutral along the Mississippi River to negatively tilted but time it reaches the Tennessee and the Appalachian Mountains IS ideal for coastal development.

The problem here is that s/w which appears to be fairly strong and swings through the Midwest on Sunday has no reason to slow down. There is no upstream blocking features such as a - NAO or 50/50 Low. Keep in mind as you look at this map you can see a strong Jet streak that is up stream which is associated with this Midwest trough as it reaches the Mississippi river
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/fp1_060.shtml

An addition the NAM/ WRF past 60 of hours is notoriously are unreliable... and any solution that the model is producing past 60 hours must be compared to other more liable models especially in the early stages of the medium-range. In this way one can do a check to see if the NAM/ WRF 66 to 84 hours solution is not bogus.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/fp1_072.shtml

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/fp1_078.shtml

And of course when we do that we find that there is no other model development which supports the operational 12z NAM. Sure the 12z GFS is a little closer to the coast and shows a bit more development but again this is because we are within the 72-hour time frame . Given how fast the system is moving and how there is no reason for to slow down I cannot find any stenotic lesions as to why he 12z NAM would have such heavy VVs over the coastal Plains of the Northeast-- from eastern VA to southern NJ to NYC the southeastern New England.
And lastly if arguendo the 12z Friday NAM solution is liable then there is the problem of Low level temperatures of which does not support all snow or barely supports a mixed event .
As for the next event December 8 -- 9 there is not much hope left this one either.
As for how long the warm interval is going to last... who knows? One thing that I do now is that the temperatures will not be as warm as what we saw in NOV. The operational European Canadian and GFS as well as those ensembles all show a seasonally mild pattern with a flat Ridge over the Southwest states and good Pacific jet slamming into northern California north to Br Columbia... and some sort weak shallow troughing over the Great Lakes and New England. Again this is a mild pattern with a lot of Pacific air but not the record or near record warmth we have seen for NOV 2006.

Interestingly the 12z GFS for DEC 17--- 372 hrs is fairly cold with some sort a significant trough developing over the central and eastern US and several other members showing a+ PNA redeveloping.
http://www.meteo.psu.edu/~gadomski/ENSHGT_12z/f372.gif

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