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Friday, November 21, 2014

Thanksgiving(eve)

11-24 early afternoon.  GFS tweaked a little to the right, but still keeps the precip in the .9-1 range. Most precip falling as snow, but not accum right away.  Some printouts below.  UKMET came in with a low over NYC?!  NAM HiRes is in and its got cold 850's and a lot of precip with surf temps near 0.  9z SREF over BM with 850s only a problem south of NJ and at the coast, and 700 temps warm for SE Mass and RI.  RGEM 12z has the R/I/S line right on us.

ukmet 12z mslp 850




GFS printouts 12z
                             12Z NOV24   * - APPROXIMATED
                              2 M     850    1000    FZING    SFC     SFC    6 HR    SNCVR
                              TMP     TMP     850     HGT     WIND    PCP     QPF     LIQ
                                   (C)     (C)     THK    (FT)    (KTS)   TYPES   (IN)    (IN)
WED 12Z 26-NOV   2.9     1.1     130    5212    03008     SN    0.00    0.00   
WED 18Z 26-NOV   0.8    -3.0     129     801    01010     SN    0.55    0.40   
THU 00Z 27-NOV   0.7    -3.7     129     801    35012     SN    0.31    0.63   
THU 06Z 27-NOV   0.1    -4.7     129     500    32008     SN    0.07    0.69   
THU 12Z 27-NOV  -0.7    -6.4     129     278    30005     SN    0.01    0.69   
THU 18Z 27-NOV   0.5    -7.1     128     634    31008     SN    0.00    0.69   

PRESS LEVEL  SFC  1000   925   850   700   600   500   400   300   200
WED 12Z 26-NOV    4     3    -1     1    -9    -8   -12   -22   -36   -60      
WED 18Z 26-NOV    3     1    -2    -3    -8    -6   -12   -22   -34   -58      
THU 00Z 27-NOV    2     1    -2    -4    -8   -11   -20   -24   -34   -54      
THU 06Z 27-NOV    2     0    -2    -5   -12   -19   -25   -33   -39   -50      
THU 12Z 27-NOV    1     0    -3    -6   -14   -22   -30   -40   -43   -47      
THU 18Z 27-NOV    3     0    -4    -7   -15   -23   -32   -43   -45   -47     


11-24 morning - Winter Storm Watch in effect for 4-8 inches.  GFS runs cold and with over .9" qpf.  Euro has mostly snow, with a mix at 0z thurs with total qpf of 1.26.   GFS all snow, accumulations iffy as surface is above freezing for some of it, but it should come down hard enough for 5:1 ratios then 10:1 ratios as colder air enters the column.  NAM is still east of the benchmark, but has all the temps at or below freezing for DXR through the event.  Nam precip in CT goes from .5-.75  to 1-1.25" west to east, but the snow maps only showing 3-6 inches.

Euro moves east 100 miles. LP now passing east of LI, still within the Benchmark

Euro printout looks like its mostly snow, though surface temps are a little warm.  I don't always believe the surface temps on the Euro as whenever there is a heavier precip event, the temps usually get to 32-33 and it accumulates.  Total qpf 1.26.  Looking at temps in the 850-500mb layers, there is one time at 0z that the 700mb temps are over 0.  So there could be a good amount of sleet during that time period.
                                2 M     850    1000   FZING    SFC     SFC    6 HR    SNCVR
                                TMP     TMP  850  HGT     WIND    PCP     QPF     LIQ
                                (C)     (C)     THK    (FT)    (KTS)   TYPES
WED 12Z 26-NOV   3.7    -1.2     130    1702    0300       0.02           
WED 18Z 26-NOV   1.7    -2.6     130     713    04010      0.34           
THU 00Z 27-NOV   1.2    -2.7     129   11049    0201      0.48           
THU 06Z 27-NOV   0.4    -6.4     128     404    34013      0.32           
THU 12Z 27-NOV  -1.9    -5.3     128     197    30009      0.10           
(IN)    (IN)

GFS 0z shows nice storm at 72 hrs. Its printout is colder at the surface and at 850mb.  Total qpf for dxr of .96. Snow map with 8-10 inches.

Then 6z snow map is a bit less further south, but still solid 6+ for most of CT.  .93 qpf on the printout with 850's of -2 to -6 through the event.  700 and 500mb temps are also all snow.

 
 
NAM runs show a little NW push with the precip, less impressive on the location of the LP.  Seems like the earlier hours have the greater shift, and later in the run the are more similar.  Its QPF for DXR on the printout is over .7, but only shows in the 3-6 range.  Temps are very cooperative.
----------------------------------------------------------------------------------------------------------------------

11-23 evening
18z GFS at 06z Thurs
12z GFS Off SC at 7am with 1012 mb, to east of OBX, hits BM late Wed nite, and off Cape Cod as 992 mb low by 1am.  Drops from 1012 to 984 in 24 hrs. 18z run is slightly more west and noticeably weaker. 12z offers 6-6" on the snow map, 18z offers 8-10" 

12z Euro starts off SC at 7am with 1008 low, looks like it goes inside OBX, off Delmarva as 1000mb low at 7pm, crosses ISP  as 992 low at 1am.  988 low off Portsmouth at 7am.  So only 20mb drop for the Euro.  Euro still puts out 12-18 inches though, which based on the track does not seem right as the 850s are too warm. Meanwhile the Euro ens control is a benchmark storm with 10-12" legit.  Euro ens mean is in between.

Euro at 6z Thurs.  Center over LI  -warm 850s


12z CMC still way offshore, brushing the coast with snow, RGEM has rain south of NYC with some snow N of NYC, but little. 12z JMA still way offshore.  GFS.25 parallel is way offshore. NAM way off shore, but brushes us.

NWS has an interesting approach - their forecast
  • Wednesday Snow likely, mainly after noon. Cloudy, with a steady temperature around 34. Chance of precipitation is 60%.
  • Wednesday Night Snow likely. Cloudy, with a low around 29. Chance of precipitation is 60%.
Their Haz Watch:


DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

A COASTAL STORM IS EXPECTED TO AFFECT THE REGION WEDNESDAY INTO
WEDNESDAY NIGHT...BUT UNCERTAINTY STILL EXISTS IN HOW CLOSE TO THE
REGION THIS STORM WILL TRACK. A COMBINATION OF SNOW...RAIN...AND
WIND ARE LIKELY WITH THIS SYSTEM.

ALTHOUGH IT IS TOO EARLY TO DETERMINE EXACT SNOW AND RAIN
AMOUNTS...THERE IS A LOW PROBABILITY OF 6 OR MORE INCHES OF SNOW
ACROSS AREAS TO THE NORTH AND WEST OF THE NYC METRO AREA BY THE
TIME THE STORM WINDS DOWN LATE WEDNESDAY NIGHT. CONTINUE TO
MONITOR NWS FORECASTS FOR THE LATEST ON POTENTIAL STORM RELATED
HAZARDS AND IMPACTS DURING THE BUSY MIDWEEK HOLIDAY TRAVEL PERIOD.

11-23 morning
0z gfs forms 1012 low off SC 12z Wed, light precip enters NY metro 15z, 1008 lp goes off OBX 125 miles east or so by 18z and snow is falling moderately.  0z Thurs storm center is just south of BM east of NJ, 6z and still 1008 225 miles east of Cape Cod, snow is tapering off in NY metro.  QPF below - most is snow as surface temps inland are under 0c and very close until the immediate coast. 3-6 inches generally in the areas shown getting qpf below.
6z gfs runs low about 50 miles off OBX, really close to the BM and deepening more than the 0z run. So much closer to shore and down to 992 as it passes the Cape.  Timing similar. Way different qpf map. However, there are temp issues with the 850 and 925 line just offshore (except RI, SE MA and Cape). Result is a widespread 6-9" storm for most areas away from the coast.
 


Euro meanwhile shifts further west, with the low going inside OBX, right off ACY and 992 over eastern LI and 984 into Gulf of ME. 850 line backs for some of the storm to about Rt 8 in CT and Cross ISL Pky in NY. Brings rain to most of CT, MA and all of RI for some of the heaviest parts of the storm.  Also interesting is that the 700mb 0 degree line is actually further north/west than the 850 and 925 lines, indicating sleet. Surface temps are above freezing for most of the area, but the Euro snow map still lays down 12-16"
Other models:  UKMET as close if not closer to coast than Euro.  My guess on that is a snow/rain/snow event for most inland areas. CMC looks like a lone wolf - no precip as low is too far offshore.  DGEX comes to CMC's rescue also with a completely offshore event. NAVGEM in between with it brushing the coast, moreso in SNE. GFS ens and parallel are east of the det. GFS.  Euros ensembles support the det. though are slightly east.  Not talking about the NAM yet. 

11-22 evening
18z DGEX brushes CT East and Jersey shore
18z GFS  moves further west.  GFS.25 is not buying it yet. The parallel gfs keeps the GL low strong and separate from the coastal.  It does bring some snow to the Cape.


18z GFS mslp 850
18z gfs snow


12z Euro seems to have moved a bit further west, but same result as 0z. Ensembles are a bit east, but close enough to support the idea of a storm.

 11-22

0z Euro and UKMEt showing a solid storm for the EC.   850 and 925 temps are cold.  Surface temps still marginal, but with values seen on the 700mb Vert velocity, there should be heavy enough snow to convert the surface to at or below freezing. 

Vertical Velocity showing heavy snow
Snow accumulation on Thanksgiving

mslp and 850 Wed evening
UKMET at hr 120

CMC and JMA still not showing anything close to the coast. NAVGEM is between 12z GFS and Euro, brushing us.
0z GFS brushes us with some snow, but is further off the coast. 6z is offshore and is less enthusiastic about forming a low. Same with 12z.  GFS ensembles showing some love for the Euro.  GFS .25 a little stronger of a low, but still offshore.

So, in summary Euro/UKMET (strong storm)  vs. GFS/CMC/JMA (offshore)  with DGEX/NAVGEM in between.




11-21 evening . 18z GFS is close to this mornings Euro solution.  Hmmm..
18z DGEX still has nothin, JMA has a little snow along the coast at hr 144.




11-21  Models all over the place, most have had a front come through Wednesday. Once in a while a wave would be seen either coming through the Lakes or off the coast.  Todays Euro is interesting though.  Morning run had snow Wed into Thurs.  Waiting for 12z graphics, but that run has a cut off upper low, stacked over a 995 surface low on Thurs nite/Fri Morn with it bombing to 980 offshore.  GFS .25 also has storm, but OP GFS does not. Still too early to look at ensembles. GGEM is offshore, GFS offshore, DGEX offshore.

12z run has a weaker storm Wed into Thurs, more offshore.  Focus on that run has an upper low meet a surface low off OBX, which then meanders a while in that area before heading ENE to a 40/65 position E of the benchmark as a 970 low. 

0z pics



12z Pics


12z pics

Wednesday, November 19, 2014

Record Cold and Historic LES

November has been pretty darn cold .  Supertyphoon Nuri, with winds over 180mph, recurved around Nov 2, headed north and recurved again on the 5th/6th.  General rule is that recuving typhoon results in trough in the east.  Nuri didn't go quietly though, becoming an explosive 920mb low in the Northern Pacific and one of the strongest storms to enter the Bering sea in history.  Nuri did weaken right after reaching its peak, but meandered until the 13th until it dissipated over the Aleutians.  Typhoons pump the ridge in front of them (think counterclockwise circulation) bringing up warmer air from the south and disrupting the circulation around the arctic (ie polar vortex)   If a ridge is created, then a trough needs to develop, and a rather large trough did develop, moving over the US resulting in the PV breaking off and sliding over the US, bringing waves of record cold.

The set up for the 5-6 feet of snow in one day over Buffalo's southtowns was perfect.  Warmer lakes, a piece of the PV, winds SW able to pick up moisture over the entire Lake Erie.


ERIE COUNTY...
   4 S CHEEKTOWAGA       65.0  1004 AM 11/19  ESTIMATED
   LANCASTER             63.0   944 AM 11/19  NWS EMPLOYEE
   GARDENVILLE           60.0   800 PM 11/18  TRAINED SPOTTER
   WEST SENECA           57.0   800 PM 11/18  TRAINED SPOTTER
   2 W WEST SENECA       51.0   700 AM 11/19  COCORAHS
   ELMA                  51.0   800 PM 11/18  TRAINED SPOTTER
   ORCHARD PARK          48.0   800 PM 11/18  TRAINED SPOTTER
   WALES CENTER          48.0   946 AM 11/19  TRAINED SPOTTER
   1 N HAMBURG           48.0   905 AM 11/19  NWS EMPLOYEE
   4 SSE BUFFALO         45.0   700 AM 11/19  COCORAHS
   2 SSW BLASDELL        44.0   700 AM 11/19  COCORAHS


But don't believe that this is the end of global warming.  While record cold hits the Eastern 2/3 of the US, there is record warmth in Alaska, Greenland and Europe.  





http://mashable.com/2014/11/10/u-s-polar-vortex-record-cold/

Thursday, November 13, 2014

Looking for first snow..

..tonite! NWS pretty aggressive with at least a dusting to two inches for the higher elevs of SW CT.  I'm always skeptical about moisture following a cold front, but every model has this happening.  It will be overnight, so perhaps a winter wonderland to wake.

 Results - not so much a winter wonderland, but a dusting.  It snowed from 10-3am, but temps stayed 33-34 degrees and it didn't snow hard enough to accumulate at that temp.