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Monday, March 30, 2015

Late March Early April

Then there is this surprise for Easter night, via the Euro.  The snow over PA includes todays snow.

Storm for Easter Saturday is coming together on the models.  GFS has pulled back west of us, Euro is pushing east, but still west of us.  UKIE looks to track just west.  CMC is just west.  I don't expect a southerly shift, but it may not take much.  Still a possibility it ends as snow.

This mornings GFS snow map . RGEM is with it. NAM is drier. Euro kills the precip before it gets here

HRRR has more precip, but not as snow

HRRR precip


3-30   Still stuck with this trough in the east.  Brought snow each of the last three days, all melted by noon.  Still another opportunity exists for tomorrow afternoon, but being during daylight with temps over 32, shouldn't accumulate.  Path of clipper headed further south today, but they will have even warmer temps.  Easter weekend still looks interesting - Euro still having the low pass well to our NW bringing rain, GFS is flatter with it being very close to snowing, though temps ahead of front are in the 50's.   I'll go with a rain ending as wet snow for Easter Saturday.

After that, the Euro weekly has -10c temps at 850 as late as 4/22, with another trough coming in for the end of the month with 850 temps under 0c.  The good news is that its not locked in completely.  But no 70's or 80's on that run for the NE.  

Monday, March 16, 2015

Spring Snow

3-20 -  Didn't get to update yesterday.  NAM held steady with .17 qpf for DXR.  GFS and Euro backed down the heaviest 6hr period from .4 to .25.  Though totals went down a little, they spread out .05 to .1" qpf over several 6hr periods.  That shouldn't accumulate.  This mornings HRRR and RAP still suggested 4-5", until the 13z run which has 3".  Temps slightly higher than forecast.  They were not forecast by any model to go above freezing, current temp is 33.2.  DP and WB temps still quite low, teens and lower 20's. 

3-18  Afternoon - GFS is now onboard

3-18  Euro still onboard with 3" of snow for the Danbury area.  QPF is .46 but looking at .39 for the 10:1 ratio time frame.  Temps do support snow.  No holes in any layer, just a matter of where the precip goes now.

Euro snow 3-18 0z run

ECMWF Deterministic FORECAST FOR:  LAT =  41.38  LON =  -73.46

                                            00Z MAR18
                               2 M     850     6 HR
                              TMP    TMP    QPF 
                               (C)      (C)     (IN)   
FRI 12Z 20-MAR  -6.2    -4.7      0.00    
FRI 18Z 20-MAR  -1.1    -7.3      0.05 
SAT 00Z 21-MAR  -2.2    -3.5    0.30    
SAT 06Z 21-MAR  -2.2    -1.9    0.09    
SAT 12Z 21-MAR  -1.9    -4.5    0.02    

GFS still at .1 qpf, for an inch of snow, but temps support snow as well.  0z and 6z NAM is also further south with QPF, but 12z may see some changes.

3-17  Euro continues on a 3-4" snow for the morning of the 21st for NYC/LI north. 850s well below 0 with surface temps at or below 0, so snow is supported.   .52 liquid qpf is currently forecast - snow ratio likely under 10:1, but it may be close.  1000-500 thickness in the 535 range, also supporting all snow.
                 2 M     850     6 HR    
                 TMP     TMP     QPF     
                 (C)     (C)    (IN)      
FRI 18Z 20-MAR   0.2    -6.9    .12         
SAT 00Z 21-MAR  -0.4    -2.9    .34         
SAT 06Z 21-MAR  -0.8    -4.6    06        
SAT 12Z 21-MAR  -1.7    -2.8    0.00      

0z GFS is less robust, with colder temps.  Only snow showers. CMC and UKMET more like Euro


DGEX brushes us with 1", but reloads and makes it look like we will get hit on the 25th.
Early NAM looks south - complete miss.
JMA from 12z yesterday has a nice deepening storm off New England 12z 3-21 after spreading .5 qpf.

3-16  First weekend of spring.... snow/rain.

Friday night into Saturday, Euro calls for 2-4 inches throughout Tristate.  This is coming from a southern storm, fairly weak, sliding to our south that will pull some cold air down and change from rain to snow.
850s and 925s support snow on this one, really most of the time. 
12z euro mslp

12z euro snow map
Then Sunday, some snow showers and perhaps another inch or two?? Scenarios where the precip chase the front don't usually work out, but there should at least be snow showers.  850s are warm ahead though.
Then a little flurries/snow showers as a warm front moves through on the 25th
3-25 warm front action
GFS supports Euro

12z GFS snow  6" for tristate

Monday, March 2, 2015

Mar 3-5

3-4 evening

Have to go with a 3-6 inch storm. In support of the storm:
12z Euro per below
12z Ukie (has 3" but 5" worth of precip)
18z GFS  .93 of precip, most after the front passes and with -10c temps at 850
18z GEFS mean has 6" 

12z and 18z RGEM has 6"

Latest HRRR with 3-4 inches, through 9am
 RAP also with 3-4 inches

SREF's now have 6"  (but they've been all over)

Going against it:  NWS has us 1-2", not even an advisory, NAM, 0z-12z GFS runs, earlier SREF's

3-4 noon  No idea - GFS/NAM say nothing.  Even GFS ensembles have a good amount. 

The 12z US maps below say it all - then compare with the 0z euro and 12z GGEM????

Euro 6" snow

gfs no snow

NAM no snow

3-3 afternoon

18z GFS goes even further south, now with only .13 qpf falling as snow over 24 hrs once it changes back.  At that rate, it doesn't accumulate.

12z GFS goes a bit further south as well.  UKMET also drifted south.  Both now the I84 area getting only a minor nuisance snow.  Cold air has been impressive this year pushing weak systems south. With no upper feature behind to dive down, and there really being no well organized low to pump a ridge in front, the southern solution may be the right one, especially if the cold front doesn't lift north as much as modeled.   Then it becomes how the waves time with the frontal passage.  NAM's .9 qpf is not .49.  Euro's .66 qpf down to .29.  GFS .4 qpf down to .23.

3-3   Nothing changing too much overnight.  Models still have brief snow on front end turning to sleeet, freezing rain then drizzle. SREF's are all over the place.   Second round is where most of these totals are.

NAM seems to be drifting south, but still gives us a good amount. 6-7"

GFS clobbers SNJ - gives DXR 7-8"

Euro ens control 8-10"
Euro deterministic 9-10"

Then the 12z Hires NAM  10-12"

3-2  Complex system with stalled frontal boundaries coming up for a two day period.  Looks like a LP will ride up through Canada bringing a weak warm front up on Tuesday, into still very cold air.  Originally temps were forecast near 50, are down to 40 now and I am skeptical we get that unless some sun breaks through after the warm front passes.  There really isn't a strong surface wind and even Upton is skeptical as to how far north this front gets. 18z GFS from today only gets to 33.  Euro to 39.   This means a snow, sleet, freezing rain to possibly rain (definitely further south) scenario.  But the last snow never changed over as the warm front barely made it to LI.  Temps aloft look pretty warm though, so I like 2-3" for Tuesday into Tues night. QPF on the 18z GFS for this first part are .27 which will be a mix, then .19 as rain before it turns to the third part.  Euro is also .27, colder to start at 850 and then warmer.  Then .09 over 18hrs as drizzle before going back to snow.

NAM is juicier to start, with .5 for the first portion, .18 for the 18 hr drizzle.  Then .89 as snow!   Temps at surface make it to 35, but NAM has been warm at surface and aloft lately.  Its also slower than the Euro and GFS.

For the snow on the backend, the Euro has .41; NAM .89 and GFS .38.   It should be noted the GFS pulled back far to the NW with the axis of qpf between the 6z and 12z runs and a little more at 18z.  GFS also has Atlantic City getting a foot.

Some snow maps - note the accuweather gfs and nam include melting so it assumes that most of the front end melts. Also posting Instant Weather Maps version  which doesn't include melting

One last point on this storm - there really isn't an organized LP on the maps just yet.  Just waves moving along the frontal boundary as it lifts north, then south .