Monday, October 27, 2014

Opening season! Snow on the maps for 11/1 -11/2

10-31 Morning

Precip shifting west  - below are some run comparisions.  LP seems to track over or inside BM on GFS/Euro and their ens.  Yet precip, is still minimal.  Wonder if the trend of increasing will continue.
Euro supports snow aloft after 18z on Saturday - temps warm at surface but if it snows/rains hard enough could turn over.
12z 10-30 Euro precip

0z 10-21 euro precip
 GFS Also increases, but the cold air stays west. LP track though is very conducive for a snow storm.

12z 10-30 gfs precip

6z 10-31GFS  precip
NAM also has pushed back, and keeps the cold to the west until precip winds down

12z 10-30 NAM precip
6z 10-31 NAM precip
CMC still pushes offshore, but has the cold air aloft, go figure.


10/30 afternoon
Nothing really changed, GFS and Euro operationals are still a little too far offshore to bring much precip other than showers of some sort.  Ensembles still further west.  Precip shield comes to abrupt end on the west side, which is suspicious. NAM on board with two storm solution, both SE of 40/68.  The first sends a plume of moisture into the NYC area though.  JMA has solid snowstorm for many in the NE.  UKMET has 990 low over or just inside BM.  CMC looks similar to NAM as it has two storms, first throwing in some moisture. Both don't have the cold arriving in time for snow.

Many are calling for snow on the boards and through social media and on the radio.  More hype than it should be at this point.


10/29  afternoon

Euro is taking one storm off this stalled front passing today and bringing it out to sea about 40/68.   Very little precip hits LI/NJ from that one. As the upper low closes off, another storm forms off southern NC.  This blows up nicely, down to 988 as it passes just SE of the BM.  Very little precip falls from throwback moisture, mostly SNJ and eastern MA and most of the area has .01 - .1 qpf.  Euro has been steady on this yesterday and today, backing off the 27th runs.  A little concerning, and what is causing confusion with forecasting this is that the ensembles bring it west of the BM with the cold air in place.

GFS never fully forms a separate storm off the front. It shows signs of it, but its ultimately absorbed by a new storm over northern NC. That storm also deepens to 988, but goes to 40/68 instead.   Without the lead storm, the cold takes longer to settle in.  The cape gets some precip, but not snow.
Precip is scant, but as with the Euro, its ens are also spread west, though not as much as the euro.




10/27 lunch/afternoon

GFS develops storm closer in, warms up the 850's but puts down over 2" of qpf while 850 temps are below 0. 

12z gfs
FRI 06Z 31-OCT   4.7    -1.8    1017      86      44    0.00     557     544   
FRI 12Z 31-OCT   5.2    -2.2    1017      83      58    0.00     556     542   
FRI 18Z 31-OCT  10.8    -2.4    1014      53      96    0.00     552     541   
SAT 00Z 01-NOV   5.6    -2.0    1013      73      79    0.00     549     539   
SAT 06Z 01-NOV   6.2    -1.3    1009      76      87    0.00     545     538   
SAT 12Z 01-NOV   5.1    -0.2    1006      98      99    0.26     542     537   
SAT 18Z 01-NOV   1.6    -1.3    1004      99      99    1.13     539     536   
SUN 00Z 02-NOV   1.4    -2.5    1011      96      99    0.68     543     534   
SUN 06Z 02-NOV  -0.7    -2.7    1017      92      84    0.04     546     533   


10/27 morning
We've had several runs indicating that snow may be in the air, as well as on the ground over the weekend after Halloween.  Not much, but Euro run 10/27 0z showing as much as 3" in NW CT with 1-2" for DXR area.  With temps at 850 at -7 to -8C, 925 at -3 and ground temps right around 0c, there is support for snow, with .2" qpf.   Northern Fairfield, Northern Westchester, Putnam and Orange are the southern extent of the snow line on the Euro.

0z/6z GFS has similar temp profile, but keeps the clipper/sw moving through with snow showers.  Yesterday's GFS had slower pattern, as did DGEX, but now both move the sw out quicker.

Important to note:  its rare that you get snow on the south side of a clipper, even in the middle of winter, so the models make me suspicious.   Granted, this isn't a true clipper, its more of a shortwave which meets another low off the coast and deepens, but its still rare to have snow in this situation.

6z  gfs
FRI 06Z 31-OCT   4.4    -1.5     131    3906    32004           0.00    0.00   
FRI 12Z 31-OCT   4.6    -2.3     131    3528    33003           0.00    0.00   
FRI 18Z 31-OCT  10.6    -2.0     132    3790    30003     RA    0.00    0.00   
SAT 00Z 01-NOV   5.8    -1.5     132    4098    07002           0.00    0.00   
SAT 06Z 01-NOV   6.1    -2.0     132    3837    04005     RA    0.01    0.00   
SAT 12Z 01-NOV   2.6    -5.0     130    1752    35012     SN    0.24    0.17   
SAT 18Z 01-NOV   2.7    -7.8     128    1231    33017     SN    0.05    0.14   
SUN 00Z 02-NOV  -0.4    -8.6     128     355    33012     SN    0.00    0.11   

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