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Wednesday, January 28, 2015

Feb 2 - all kinds of crazy

2-3 RESULT - most of Interior CT has totals in the 6-10 inch range, with the SE portion having 3-4  The storm dumped 7" first, then switched to sleet for several hours, before dropping another 3" in 3 hours at the end.  Total of 10" in Danbury.  There were several spots in CT which had 12-14, but not widespread.  Central NJ had 2-4, NE NJ had 4-8 and Sussex cty, and northern Passaic had generally 6-10.   Most of Hudson Valley north of 287 had 6-10.  Where I didn't forecast was LI, which had I it would have busted low.  They had mostly 4-8 (I was thinking 2-4) with a few under and one report of 10".  The bigger surprise to me was Albany which ended up with 10-14" and some higher.
Snowfall amounts

2-1  Southern CT remains right along the r/s line. Really should be snow/sleet/zr line. 0z GFS and 0z NAM went all snow for most of the state, 6z GFS and NAM went back to a 3 hr period of above 0c temps at 850.  Euro holding steady at keeping the 0 line closer to NYC. NWS still has us in a 10-14 inch range.  But 6zGFS (.88),0z Euro (.87)  and 6zNAM(.88)  all have less than 1" qpf.  The SREF's have over 1" but also have the 0c line at 850 on the CT MA border and only puts out 4" of snow in Oxford.  So with only the SREFs having over a 1" of qpf and it being the warmest with the least snow, and the other models either with less than 1" qpf and a chance for mixing, the call remains 6-10" for most of CT north of the Merrit.  4-8" for the coast.  We'll be closer to high end of the range if it doesn't mix, closer to the low end if it does.   


Euro qpf

NAM qpf

6z GFS precip

6z GFS snow map


SREF for oxford
In summary, with the qpf under 1" and temp profile close to marginal, I have a difficult time buying a 10-14" snow fall for north and central CT, and also think the 8-10 NWS call for SE CT is a bit high.  I'm thinking  6-10 for most of central to northern CT with 12" possible along the MA border NW of 84.  4-8 for southern CT. 
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1-31 -Temps now an issue. Nam run become borderline for DXR and rain/ice for south of DXR.  Then 12z went back to all snow for all of CT.  GFS 12z came in much warmer at 850, with little snow south of DXR and snow/ice for DXR, still at 6-8 inches though. Areas north of 84 still mostly snow.  0z Euro held firm.  SREF's dropped from 9" of snow to 4" with ice introduced in the 9z run, not a good solution for us.  Still like 6-8 maybe 10 inches here, mostly front end snow.  Worried about liquid precip falling onto a wet snow on the trees and lines.


12z gfs at its warmest

12z nam at its warmest


6z nam at its warmest



1-30  Temps don't seem to be an issue (yet)  so just looking at latest precip maps most are .5 to 1".  This supports a 6-10 inch storm, perhaps a bit more depending on ratios.  Most models have the 850 line in between Philly and NYC.  This will cause some variability in forecasts depending on how that trends.  NAM is warmest so far and pulls the 850 line as far north as the CT coast.  North of NYC should be all snow though.  Need to watch any further shifts north.

Euro 12 precip

GFS 18z precip

NAM 18z precip

CMC 12z precip
Here's a view of the warmest run at 850. Most of NJ, NYC and LI get rain or freezing rain



1-30  No pics just yet, but the gfs, nam, cmc and euro all trending north and wetter.  Some qpf #s:  GFS: 0z  .51; 6z .54; 12z .63.  NAM 0z .25; 6z .5-.75; 12z .75-1 (note this is the end of the NAM range so the 0z run doesn't capture the entire storm)  Euro 0z .73 and 12z .95. UKMET is pretty far north, but cold enough from what I can tell for snow.  CMC went from exiting CONUS at OBX to exiting at NJ.   Euro snow map below seems overdone, but the way things are trending  could end up like this.   We should see at least warning criteria (6+) snow from this storm. 



CMC snow map

Attached Image

1-29 - models are no longer mayhemic.  Instead they are remarkably aligned, with some differences as to whether the storm exits ene or ne, and if it exits off OBX or Delmarva.  But no storms to the lakes, or off SC today.
GFS - all runs show system exiting off OBX and tracking ENE outside the BM.
GFS ensembles - also support the southeast solutions
But there is some precip associated:  0z is .41, 6z is .13 12z is.14

Euro - 0z misses us completely (0 precip) , 12z is more robust and brushes our area with .3 precip.  BTW it crushes us on the 5th with 1.34 qpf (-1 850s though)
12z euro


JMA is difficult between frames, but leaves us with about an inch of precip, so its the most aggressive now.

JMA
CMC 0z run looks great, 12z misses us completely
cmc 0z
 12z UKIE is similar to the 0z CMC.  0z ukie looked the same, but difficult to see between frames


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ts MODEL MAYHEM for next Monday - 5 days out and they are all over the place.  Lots of images for this nuttiness

First lets start with the GFS - 18z yesterday had solid snow storm, 0z today goes to our north, 6z kinda right over us, 12z doesn't even have a storm, just a wave sliding south. 



Then there is the CMC and UKMET which have it running west of us, similar to the 0z GFS

Euro and DGEX are showing snowstorm
DGEX

Euro
And yesterdays JMA which has nothing, not even a wave
GFS and Canadian Ensembles have a low south of LI as well.

12z Euro comes in looking like the 12z GFS - southern wave slides out.

Todays JMA came to the table

Tuesday, January 27, 2015

Activity on Feb 2nd, 5th and 7th

2-3  opened separate posts for these, but the 7th became the 9th,

1-27 evening
Euro operational looks awful, but the ensemble looks great for the 2nd.  18z GFS came in with the three title storms still as well.


1-27
Looks like someone turned the winter switch on. After todays storm, we have a clipper with some light snow perhaps overnight thurs/fri. In the long range, the Euro control as storms running from the gulf to the midatlantic on the 2nd, 5th and 7th.  The 7th hits the NYC area, while the others slide off south of DC. Something to watch at least.   Euro determinstic has a similar look to the 12z gfs for the 2nd with some good front end snows, but eventually warms aloft.  Could be similar to last Saturday.


GFS long range - more snow with clipper thurs/fri, storm on 2nd hits us square on, but may give us front end snow (oddly my accuweather forecast has a high of 19 and low of -9).  The 6th and 7th have separate systems that just slide south.  Like the Euro control, somethings to watch.

GFS 12z run has a nice hit for the 2nd, 6th and almost 7th.


CMC slides the LP the 2nd to our south, but does bring some snow.  Then it gets funky around the 6th.
DGEX is rain on the 2nd.
JMA slides a wave way to our south on the 2nd.
UKMET looks like it wants to rain, but doesn't go that far out.

Saturday, January 24, 2015

1-27 "clipper" or Miller B

1-27  From my facebook post
 I tried to demonstrate what your local meteorologists go through with a snow storm.  While they get the day to day and most storms correct, when there is a bust like this, its good to see what they were looking at and realize that with all the info out there, snowstorms are still really tricky.   With this one, the mid range models caught on late (Saturday), but did get the track of the storm mostly correct from there.  The precip field was wrong though.  The short term model (NAM) held off until Sunday then went nuts with precip, only to back off once or twice, and then last night at 7pm, backed off completely.  The real time models (HRRR/RAP) run 18 hours out, so they couldn't be used until yesterday.  They showed basically no precip for NNJ, Western CT, though did have it for NYC east and east of Bridgeport.   Models aside, the satellite looked good, and right before I went to sleep at midnight, it was snowing hard and the radar looked like it had a fire hose pointed right at NYC/Danbury.  But bands are hard to predict, and so was the sharp cutoff of precip.   Normally a 980mb low slowly moving over the 40/70 benchmark would yield 12-18 inches here, but it didn't.  So congrats to those east of Hartford and LaGuardia where 1 to 3 feet fell.  I'm up to 5.5" and wondering if that last band makes it here.

1-25
 Just got back home and checked on these two things first. QPF trends - NAM from 0z run to 12z run moved west and increased. 18z didn't shift east much with the bulk of the precip, but did lower the amounts. Next run may show a trend.






GFS 0z came to the party in Newark (1.21qpf ewr) , 6z GFS came with booze (1.57qpf), 12z left the party (.94) and the 18z drove away(.92). So there is something to watch.






Second - SREFs. Compare the 15z with each run before and watch the spread lessen, but amounts increase. This is good (at least for Oxford)
15z - lowest member 7", range 7"-30" but only 1 member under 15"


9z 1" to 43" 5 membs

3z range 2" to 30"

JMA seems onboard
CMC has a bit of a different approach, but still produces alot



NWS Upton AFD
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
     A LIFE THREATENING...HISTORIC WINTER STORM EXPECTED FROM LATE
MONDAY INTO TUESDAY...

NWP GUIDANCE CONTINUES TO BRING THE INGREDIENTS TOGETHER FOR A
DANGEROUS...HISTORIC BLIZZARD AS A SECONDARY LOW FORMS OFF THE
MID ATLANTIC COAST ON MON. THIS LOW WILL UNDERGO RAPID
INTENSIFICATION AS THE PARENT UPPER LOW CUTS OFF ALOFT NEAR THE
MID ATLANTIC MON NIGHT...STALLING SE OF MONTAUK LATE MON NIGHT
INTO TUE. MSLP DROPS NEARLY 30 MB IN 24 HR FROM MON AM TO TUE
AM... BEFORE GRADUALLY FILLING.

THIS WILL PLACE THE FORECAST AREA ON THE NW FLANK OF THE
LOW. AFTER LIGHT WARM ADVECTION SNOWFALL OF 1-3 INCHES DURING THE
DAYTIME HOURS MON IN ADVANCE OF THE SECONDARY LOW...A PROLONGED
PERIOD OF MDT-HVY SNOW EXPECTED IN THE DEFORMATION ZONE.
FOLLOWED 12Z NAM/ECMWF CLOSELY...WITH BOTH MODELS SUPPORTING QPF
UPWARDS OF 2 INCHES LIQUID EQUIVALENT...WITH THE HIGHEST AMOUNTS
NOW EXPECTED NOT ONLY ACROSS ERN LONG ISLAND/CT BUT ALSO FARTHER
WEST INTO SW CT AND THE NYC METRO AREA/WESTERN LONG ISLAND...AS
MODELS OFTEN DO NOT PLACE THE AREA OF MOST INTENSE MID LEVEL
FRONTOGENESIS FAR ENOUGH WEST. SNOWFALL RATES OF 2-4 INCHES PER
HOUR EXPECTED LATE MON NIGHT INTO TUE MORNING. MUCH OF THE AREA
SHOULD SEE AMOUNTS OF 20-30 INCHES...LOCALLY HIGHER WHERE BEST
MESOSCALE SNOW BANDING SETS UP.

IN ADDITION...THE DEEP LOW PRESSURE COMBINED WITH STRONG HIGH
PRESSURE TO THE NORTH AND WEST AND HEAVY FALLING/BLOWING SNOW WILL
CREATE BLIZZARD CONDITIONS ACROSS THE ENTIRE REGION. A BLIZZARD
WARNING IS NOW IN EFFECT...WITH POTENTIAL FOR SUSTAINED WINDS UP
TO 40 MPH ON LONG ISLAND...AND WIND GUSTS RANGING FROM 40 MPH
INLAND...TO 50-55 MPH MOST ELSEWHERE...TO 65 MPH ACROSS ERN LONG
ISLAND...WHERE A BRIEF HURRICANE FORCE GUST CANNOT BE RULED OUT.

TEMPS DURING THE STORM WILL GENERALLY BE IN THE 20S...EXCEPT
FALLING TO 15-20 MON NIGHT INLAND. WIND CHILLS WILL BE MOSTLY IN
THE SINGLE DIGITS TO MID TEENS...BUT AS LOW AS ZERO TO 5 BELOW
ACROSS SOUTHERN CT.

THANKS TO ALL NEIGHBORING WFOS...ERH AND WPC FOR COLLABORATION
THIS AFTERNOON.


 1-25 morning


1-24 afternoon
12z ukmet is on board too.  CMC has it, east, but its kinda loopy
SREF's for Oxford Airport


Euro bombs low to 980, upper low stacks over it just east of ACY.  The result is the snow map below

30+ inches 12z euro


1-24
Models have been pushing the clipper coming through further south - this has been the case all year and they usually have resulted in nothing or less than an inch.  I wrote this one off a few days back and have watched models push it south.  But now there seems to be some blocking, probably due to the current low.  Instead of the clipper going through S. IL, KY, VA/NC and out to sea, it bombs once off the coast and heads N just off the Cape (per Euro).  Actually looks like the trough goes negative, a 500mb low forms and stalls the LP as it deepens. Interestingly, its further out to sea than todays storm, but has the same amount of moisture - red flag.  With the qpf being .5-.75 per below map, and colder air and higher snow ratios, this should be another 6"+ storm. Don't see any mixing issues for anyone in NJ, NY, CT, RI

NAM agrees! No temp issues there either.  This qpf should be a foot or more.
12z GFS (as usual lately) is further east, but still impressive for E. Mass. Only puts .2" down for DXR.