Saturday, December 13, 2014

Mid Dec to Christmas

12-21 - dusting so far, light snow on and off from 3:30 on the 20th through now (10am 12/21)

12-19 No real changes, UKMEt has nothing, Euro has an open wave, yesterdays late JMA had a benchmark storm with no cold air. GFS shunts it out to sea.  Nothing more to see here, no further posts unless there is a change.


12-18 - this mornings models show either rain or nothing.  I think the storm on Christmas is overpowering it and pulling in a lot of warmer air.  CMC doesn't even have a storm.  Euro blows the weak  storm off to our south, but continues to warm up.  GFS actually develops the storm, brings it over the benchmark, but the flow aloft ahead of the storm is from the south.  Once the 850 low forms, the incoming Christmas storm doesn't allow it to pull in colder air.  So it results in rain.

12-17  0z Euro run develops a new coastal after the impulse brings light snow/rain in the area.  This coastal moves from 1016 off OBX, to 1012 in the pocket and 1008 over Cape Cod.  All rain for tristate.
Euro 1012 in pocket


0z GFS slides the first system out to sea off SC with nothing for us.  But now it also is forming another storm.  1012 off obx, but it moves east, but has an inverted trough/warm front hitting us Tuesday.  6z has more moisture for the original light snow event, also has a weaker low off NC heading NE which looks to throw back some moisture, but again, while at first it looks like an inverted trough, I'm thinking the moisture is actually from the warm front ahead of the Christmas storm.


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12-16  GFS and Euro in agreement on nuisance snow Sunday, DGEX further east with rain. NWS at 40% chance.  Thinking light snow, but still keeping an eye on it. Euro went negative tilt with the trough causing moisture to fall back in

Euro still has1-3/2-4 inch event for the 21st.  0z run was a trace-1" but the 12z came back with more.  Thickness and temp profiles look like all snow for most of the area, except perhaps coastal areas and SNJ.  Storm is weak and slides off the coast, SE of the BM, but leaves some moisture
Loading Maps...
12z Euro qpf 21st


GFS agrees, QPF similar to Euro, snow map as well
Loading Maps...
GFS Snow


JMA has an interesting map  -it throws back a lot of moisture
Loading Maps...
JMA

6z dgex looks much further east
Loading Maps...
dgex



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12-15 afternoon - ideas of snow fade away
12z
12z GFS 12-21
GFS showing snow showers T-1" of snow on the 21st.
JMA shows a nice hit, .5 or so precip, has 1014 low over PA and OBX  at 144hr and bombs out to a 988 low at 42N65W at 168hr.  900mb, 850mb and 700mb temps below freezing all of the area for hrs 144 and 168 (what happens in between, can't tell).
12z Euro is a miss for the TriState area and north.  Brushes Cape Cod and SNJ, but not measurable.
UKMET positions the low over the Delmarva, should be close enough for precip, mostly snow.
Canadian is out to sea
 Euro ensemble agrees with the UKMET with placement over delmarva
 




For Christmas...
Euro has a 998 low going right to our west, influenced by a low over the GL. Rain late on the 24th.  Ensemble agrees with GL low idea
Canadian has a GL low, but forms another one far off the coast.
GFS takes a low out to sea to the SE of us - Jacksonville to 100miles east of OBX, but then the GL low blasts through,  see below. Snow map has nothing though.









12-15 morning
0z Euro has storm on 21st moving up to the Delmvarva from SC, but then ENE out to sea, bringing snow to SNJ, and perhaps a little snow further north. Christmas storm now on Euro comes from the Lakes and probably isn't more than a dusting-2".  Last frame is Christmas eve.
0z and 6z GFS have the storm on the 21st very weak, with two sections moving NE, one hits us, one misses.  Total precip.25 to .5 so a 2-4 inch event.  Both runs have the Christmas storm moving to our west now.  0z gfs has a 980 low over Michigan moving north.

Loading Maps...
GFS precip for 12-21
12-14
0z euro det not much on the 17th, mostly light rain.  still a hit, though a little off the coast for the 21st
12z euro closer in and brings to 988mb.  850's are a little warm for LI, southern half CT and Southern NJ for a frame, but 700mb, 925mb and surface temps support frozen.  The track is dubious -VA/NC border 0z sunday, to Cape May, to just off ACY, to inside ACK (nantucket) - each spot 6 hrs later.  .75-1 qpf.  12+ from KY, WVA, Central PA to Catskills.  9-12 NNJ, EPA, WCT, HV, 6 elsewhere in New England.
 Euro EPS has the 21st storm a little to our west, with a mix, and a northern branch shortwave hitting us on Christmas for a nice couple of inches.

GFS

0z  17th some scattered rain showers, 21st a minor snow event/borderline rain, but it crushes the NE on Christmas - goes from 988 100 miles east of Cape May to 972 low over Boston with 1.2 of qpf.  925mb layer is above freezing for part of it resulting in sleet/fr rain mixing in. But surface temps, 850 and 700 all below freezing.
Merry Christmas


 The 12z run has rain on the 17th, a small snow, snow to rain event on the 21st as it has a northern and southern system to our north and south.  Then for Christmas, the low from the 0z run is 500 miles or so west, over the Great Lakes, but somehow reforms over Boston and hits us with a little snow on the backside.

12z gfs snow on Christmas

CMC
0z - light rain on 17th, nothing on the 21st, shortwave in Northern branch for snow on Christmas
12z doesn't really develop it and sends a weak storm out to sea off SC


 update  12z euro hits NJ/NY/CT/PA on the 21st

18z GFS hits on Christmas


12-13  Multiple opportunities through Christmas

The 17th has some precip coming through, looks like rain, but some runs have a storm forming as the front passes.  Worst case snow scenario would be 2" or less and thats a long shot.  Euro and GFS have this feature - NWS has mix forecast, but again its light.

Next opportunity is the 21st.   Euro EPS has been on this, the operational slid it out to sea yesterday but is moving it NE now.  GFS 6z has a nice run for snow
6z GFS - storm on 21st

Christmas Eve/Day - Models loading a system in the Gulf which looks like it will run up NE around Christmas Eve. Euro EPS has a upper low dropping into the middle of the country, which implies the storm will go to our west, but there could be a redevelopment off the coast.   GFS says it wants to deluge us.
6z gfs storm Christmas eve
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