December 17th Clipper Discussion

[Damage In Tolland]

From Pete Bouchard's blog:

" Late this afternoon, some new weather maps came in showing a much more powerful and SLOW storm. One so slow that it keeps the snow going through the night and into the first half of Wednesday. I have two thoughts on this.

I'm not biting.

Yet."

Days and days of snow?

[ROOSTA]

So if the 00Z suite goes bazookas and nukes. Umm, well lets just say they all trend stronger, sooner than later. It looks as if this s/w starts bombing just 100 miles to the south and slows the second s/w phases. Just some of the little nuances to watch for.  

 

Man those HGTS. in the NPAC look mighty fine but transient. The recovery that follows looks sweet.   

[N. OF PIKE]

So anyone got any insight beyond the model mayhem.

Blizz, what are your thoughts. 1'st sw or 2'nd or both or neither.

I gotta catch Harv at 11

[Damage In Tolland]

So anyone got any insight beyond the model mayhem.

Blizz, what are your thoughts. 1'st sw or 2'nd or both or neither.

I gotta catch Harv at 11

I don't think there will be 2 seperate events or waves. I could see 2 periods between tomorrow morning and Wed noon where we see see much of the accumulations region wide with lighter snow interspersed but I think the idea of one more consolidated storm is probably a better idea

[Rjay]

I don't think there will be 2 seperate events or waves. I could see 2 periods between tomorrow morning and Wed noon where we see see much of the accumulations region wide with lighter snow interspersed but I think the idea of one more consolidated storm is probably a better idea

2 periods of snow from 2 different waves..........

[N. OF PIKE]

My weenie 18z btv wrf 4km dwindles qpf again. For bos/ne mass

Has first wave push thru durin day w a little less i thump (which i buy) then gets the storm wrapped up as more energy swings thru to far into the g.o.m except for down east (Portland on east).

Perhaps this is what we see a general 2-3 inches and then down east gets double +

[Clinch Leatherwood]

So if the 00Z suite goes bazookas and nukes. Umm, well lets just say they all trend stronger, sooner than later. It looks as if this s/w starts bombing just 100 miles to the south and slows the second s/w phases. Just some of the little nuances to watch for.

Man those HGTS. in the NPAC look mighty fine but transient. The recovery that follows looks sweet.

Look at the 0z euro vs the 12z. Talk about changes. Model chaos

[SnowGoose69]

If you look at the latest HRRR and what it shows from 10-15z there is zero doubt it's hinting the 18z GFS may be onto something it seems to show a light snow band passing through NYC into SNE 10-14z but there are interesting going ons way back to the SW

[CoastalWx]

I like the 18z BTV WRF.  CF near my fanny.

[kdxken]

Boy this GFS run evolution is all of a pubic hair away from being a short-duration ... no notice blizzard on the eastern coastal plain....  

 

1008 to 990mb and falling, in 10 hours passing from S of ISP to the outer GOM should produce a wind concern for the eastern shores and certainly the Cape and Islands.  Totally down to 978mb by 18 hours is well within the bombogenesis criteria.      

 

Jet dynamics relaying into the NP out of the Canadian western cordillera and we'll see how the 00z's run with this newer grid input.   I thought the GFS' quicker deepening rate and sharper mlv wave-break on he 18z to be intriguing.  As is, the GFS can't get any closer spatial-temporally without this being a much more important impactor.     

Like this one?

 

"A wild northeaster surprised Southern New England yesterday with near-blizzard conditions and a bizarre thunderstorm, closing Logan International Airport, gridlocking thousands of homeward-bound commuters, and dumping more than a foot of snow in some communities."

 

My street :

[Clinch Leatherwood]

If you look at the latest HRRR and what it shows from 10-15z there is zero doubt it's hinting the 18z GFS may be onto something it seems to show a light snow band passing through NYC into SNE 10-14z but there are interesting going ons way back to the SW[/quote

If and probably when we see this change tonight the question will be why. Why did it take models so long to latch on.

[SnowGoose69]

If you look at the latest HRRR and what it shows from 10-15z there is zero doubt it's hinting the 18z GFS may be onto something it seems to show a light snow band passing through NYC into SNE 10-14z but there are interesting going ons way back to the SW[/quote

If and probably when we see this change tonight the question will be why. Why did it take models so long to latch on.

Too many vorts and not sure which one to focus on or how to develop it

[Cold Miser]

I like the 18z BTV WRF.  CF near my fanny.

Do you have an estimated start time down here?

[Baroclinic Zone]

Do you have an estimated start time down here?

8-9am.

[N. OF PIKE]

I like the 18z BTV WRF. CF near my fanny.

We toss

[Cold Miser]

8-9am.

Thanks.

 

Have to prepare for the impending delay or cancelation of school panic for 2" of snow.

[N. OF PIKE]

Well there is still the chance we get sort of screw'd wrt to snow. I can see this first batch of precip becoming lighter from first Sw and second sorta hooking up further Ne ward and sort of slowing second one down half way between cape Ann and Arcadia national park.

We still could get a 1 inch screwgie, no?

[Tropopause_Fold]

Well there is still the chance we get sort of screw'd wrt to snow. I can see this first batch of precip becoming lighter from first Sw and second sorta hooking up further Ne ward and sort of slowing second one down half way between cape Ann and Arcadia national park.

We still could get a 1 inch screwgie, no?

Agree

[Baroclinic Zone]

We toss

 

Loved my back yard for QPF.  What the hell was that smoking?  0.75 for me with 1"+ 5mi away.  LOL

[Damage In Tolland]

We toss

Whats it got for other areas?

[Baroclinic Zone]

Whats it got for other areas?

http://www.erh.noaa.gov/btv/html/4kmwrf/index.php

[N. OF PIKE]

Whats it got for other areas?

A bit less qpf EXCEPT a little weenie streak in se mass of like .6 -1.0) qpf in 6 hrs ne to the fishes and Arcadia national park.

Also gives nyc .40 or so . .35-.45 ne mass

[Baroclinic Zone]

4pm discussion from BOX

 

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
FAST MOVING COASTAL LOW WILL BRING A PERIOD OF ACCUMULATING SNOW
TO SNE TUE INTO TUE EVENING. MODELS STILL SHOWING SOME DIFFERENCES
WITH THE TRACK OF THE LOW. NAM/SREF ARE ON THE NW ENVELOPE OF
SOLUTIONS WITH TRACK ACROSS THE CAPE COD CANAL. GFS/GEFS IS
FARTHEST S ACROSS ACK WHILE ECMWF OFFERS A NICE COMPROMISE
BETWEEN THE TWO CAMPS. WE THINK THE NAM IS TOO FAR N GIVEN ARCTIC
AIRMASS WHICH WILL BE MOVING INTO THE REGION AND BAROCLINIC ZONE
TO THE S. COASTAL LOW IS NOT VERY STRONG AND SHOULD PASS MOSTLY S
OF NEW ENG BUT CLOSE TO THE ISLANDS PER ECMWF SOLUTION.

MOST OF THE FORCING IS FOUND IN THE LOW LEVELS WITH STRONG LOW
LEVEL FRONTOGENESIS AND ISENTROPIC ASCENT INTO THE DENDRITIC
GROWTH ZONE. THIS BANDING SIGNAL IS PROGRESSIVE GIVEN WE ARE
DEALING WITH AN OPEN WAVE AS IT MOVES THROUGH SO DURATION OF
HEAVIEST SNOW WILL BE SHORT...BUT THE WILDCARD WITH THIS EVENT IS
THE INSTABILITY. MODELS SHOW VERY STEEP MID LEVEL LAPSE RATES NEAR
8 C/KM TUE AFTERNOON WHICH IS VERY IMPRESSIVE. TOTAL TOTALS ARE
IN THE MID/UPPER 50S. THIS INDICATES POTENTIAL FOR MESOSCALE
CONVECTIVE BANDS WITH HEAVY SNOWFALL RATES POSSIBLE AND
THUNDER...BUT THERE IS LOW PREDICTABILITY WHERE THESE BANDS MAY
DEVELOP.

WE USED A BLEND OF GFS/ECMWF TO DERIVE SNOWFALL. HIGHER QPF IS
EXPECTED NEAR THE COAST WITH LESS FURTHER IN THE INTERIOR BUT HIGH
SNOW RATIOS WILL BE A FACTOR...ESPECIALLY IN THE INTERIOR WHERE
TEMPS WILL BE IN THE TEENS. STRONG THERMAL GRADIENT ACROSS SNE TUE
WITH TEMPS RANGING FROM THE TEENS NW TO NEAR 40 OVER THE ISLANDS.
WE WILL ISSUE A WINTER WEATHER ADVISORY FOR A GENERAL 2-4 INCHES
ACROSS MOST OF SNE...LESS FOR THE CAPE/ISLANDS WHERE IT IS LIKELY
THERE WILL BE ENOUGH BL WARMING FOR A CHANGE TO RAIN MID/LATE
AFTERNOON. IN FACT ACCUM WILL PROBABLY BE LESS THAN 1" FOR THE
OUTER CAPE AND ISLANDS. AND RAIN/SNOW LINE COULD GET INTO SOUTHERN
RI AND SE MA AT THE END OF THE STORM TOWARD TUE EVENING.

WHERE CONVECTIVE BANDS DEVELOP...POTENTIAL IS THERE FOR 6+ INCHES
BUT NO WAY OF KNOWING WHERE THIS MAY OCCUR AND THESE HEAVIER
AMOUNTS WOULD BE ISOLATED. CURRENT THINKING IS MAX SNOWFALL MAY
END UP ACROSS CENTRAL/NE MA INTO NE CT AND NW RI...BUT THIS CAN
CHANGE. THE CONCERN IS HEAVIEST SNOW WILL LIKELY BE AFFECTING THE
EVENING COMMUTE ACROSS INTERIOR EASTERN NEW ENG.

PRECIP WILL TAPER OFF FROM SW TO NE LATE TUE AFTERNOON INTO THE
EVENING. NE MA AND S NH WILL BE THE LAST TO SEE THE SNOW END. NOT
SURE HOW MUCH CLEARING WILL OCCUR TUE NIGHT.

[N. OF PIKE]

Box obv not high confidence earlier , at least as of 430 no snowfall accum map.

Edit i see the new one.

[SouthCoastMA]

Loved my back yard for QPF. What the hell was that smoking? 0.75 for me with 1"+ 5mi away. LOL

Yea..gives MBY >1.0" in a weenie stripe, which likely won't verify. But fun to look at

[Clinch Leatherwood]

This may be a shocker to all of you...the new 0z NAM isn't going to be anything like the previous NAMs based on the first 6 hours at 5h.  Cracker Jack model...someone new gets the prize this run.

[N. OF PIKE]

I bet this one jackpots the fish ( betting on a weaker 1'st sw and second sw that bombs just off shore)

[ineedsnow]

Ill be happy with a couple inches tomorrow anything more is a bonus. Eastern areas look good though

[Clinch Leatherwood]

much weaker through 12 or so in PA.   Going to focus more on later developments this run.  This ought to be good.

[ORH_wxman]

21z SREFs sliced back...hopefully that isn't the 00z trend.