Febuary 22-24

[ag3]

Even at hr 132 the surface freezing line is directly over the city and the north shore of Long Island with precip beginning to come to an end.

SV doesn't have soundings.

[bluewave]

If the SE ridge wasn't bridging with the Canadian "block", then I'd actually be excited for this threat.

But I suppose it's possible we could pull a rabbit out of a hat. A dynamic system off the coast in late February shouldn't be scoffed at, though this pattern warrants extreme skepticism right now.

 

Yeah, the rabbit out of the hat that we need is for the OP to be correct with the closed low solution at day 6.

The ensembles look more progressive at this point which makes me a little weary of the 0z OP.

 

[jm1220]

The danger is that with the SE Ridge in place, the Euro trends a little further north and this turns into an inland jackpot

ending as some slop at the coast.

 

00zECMWFENS500mbHeightAnomalyNA120.gif

With the blockiness to the north, I would imagine there being resistance to the storm getting too far north. But this winter, you can't bank on anything.

[PB GFI]

Yeah, the rabbit out of the hat that we need is for the OP to be correct with the closed low solution at day 6.

The ensembles look more progressive at this point which makes me a little weary of the 0z OP.

 

Geopotential32at32500hPa_North32America_144.gif

The Euro 0z control run goes berserk 132 - 138 , its been on it for 3 runs now , and with the last 2 systems the Euro ensembles and operational have come too it ... its probably overdone but it has been 1 st to pin these systems out .

[RUNNAWAYICEBERG]

With the blockiness to the north, I would imagine there being resistance to the storm getting too far north. But this winter, you can't bank on anything.

 

true..but it kinda looks like a fake block to me. it might get the job done for a thread the needle, but it could easily be shoved out of the way.

[mikemurph44]

Before people go nuts and start predicting a snowstorm with totals for saturday night, keep in mind that the euro ensemble mean did not agree with the operational run.

[IsentropicLift]

The 12z GFS can not seem to make up its mind. Shows signs of a coastal in the Delmarva at hr 99, then a low down in Georgia at hr 102 and then very broad low pressure by hr 108 along the SE coast. Hr 111 weak low pressure about 75 miles east of Ocean City, MD. Brushes Long Island and southern New England but it's a miss. Slightly better and further north than 6z though. Looks nothing like the Euro.

[MJO812]

The 12z GFS can not seem to make up its mind. Shows signs of a coastal in the Delmarva at hr 99, then a low down in Georgia at hr 102 and then very broad low pressure by hr 108 along the SE coast.

 

Weak warm coastal at 114 hours. It did look like the GFS wanted to get the coastal going further south.

[Allsnow]

Gets it going to late this run. Congrats sne

[IsentropicLift]

Weak warm coastal at 114 hours. It did look like the GFS wanted to get the coastal going further south.

See my edited post.

[MJO812]

Gets it going to late this run. Congrats sne

 

Not really. Nothing like the Euro. It's weird that the energy gets sheared out like that in the southeast.

[IsentropicLift]

Gets it going to late this run. Congrats sne

Not even, it's pretty warm even for them. At hr 120 the surface freezing line is north of Boston. Verbatim probably a sloppy few inches. Waiting for the snowfall maps to finish updating but so far nothing through hr 114.

 

Edit: The GFS is 1-3" for interior parts of central New England. Mostly where MA, VT and NH meet.

[mikemurph44]

Not really. Nothing like the Euro. It's weird that the energy gets sheared out like that in the southeast.

Look at the overall pattern setup this weekend, it's really not that surprising, the long wave synoptic setup sucks

[Zir0b]

The 12z GFS can not seem to make up its mind. Shows signs of a coastal in the Delmarva at hr 99, then a low down in Georgia at hr 102 and then very broad low pressure by hr 108 along the SE coast. Hr 111 weak low pressure about 75 miles east of Ocean City, MD. Brushes Long Island and southern New England but it's a miss. Slightly better and further north than 6z though. Looks nothing like the Euro.

There's 5 different shortwaves/impulses across the CONUS hr 120, interacting with each other in some way...very convoluted setup and I don't expect any model to have a good handle on things for another 3 days 

[NEG NAO]

There's 5 different shortwaves/impulses across the CONUS hr 120, interacting with each other in some way...very convoluted setup and I don't expect any model to have a good handle on things for another 3 days 

i think the events chances increase by at least 10% every run the EURO keeps showing the same solution from here on in

[Weathergun]

We need to see better interaction between the northern and southern streams on the GFS. The ECMWF last night had both streams phasing to our SE, at the last minute.

[NEG NAO]

HPC Discussion from late this morning favors the Euro solution

 

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1049 AM EST TUE FEB 19 2013

VALID 12Z FRI FEB 22 2013 - 12Z TUE FEB 26 2013

...WET AND ACTIVE WEATHER PATTERN TO CONTINUE ACROSS THE US... 

OVERVIEW...
MANUAL SURFACE GRAPHICS CONTINUE WITH THE PROGRESSION OF SYSTEMS
ACROSS THE MIDWEST AND EAST COAST. THE 19/00Z ENSEMBLE GUIDANCE
WAS BEST REPRESENTED BY THE ECMWF THROUGH DAY 5...WHICH REMAINS ON
THE SLIGHTLY SLOWER SIDE OF THE SPREAD VS THE CANADIAN/GEFS AND
NAEFS. SPREAD ENLARGES ACROSS THE EAST PACIFIC AND DOWNWIND INTO
THE CENTRAL PLAINS/GREAT LAKES FOR DAYS 6-7...AND MUCH OF IT...IS
TIED TO TIMING INDIVIDUAL SHORTWAVE STRENGTH EJECTING OUT OF THE
CENTRAL ROCKIES.

SYSTEM RELEVANCE...
THE DAY 3 SYSTEM TRACKING ACROSS THE CENTRAL STATES REMAINED ON
TRACK WITH LITTLE VARIATION FROM CONTINUITY.
DOWNSTREAM...CONDITIONS REMAINED FAVORABLE FOR SECONDARY
CYCLOGENESIS ALONG THE CAROLINA COAST/PIEDMONT REGION AND BROAD
ISENTROPIC LIFT/ UPGLIDE OF GULF MOISTURE INTO THE MID- TO
UPPER-LEVEL CIRCULATION POSITIONED INVOF THE GREAT LAKES.

THE DAY 4-5 SYSTEM EMERGING OFF THE CAROLINA COAST REMAINS IN A
FAVORABLE POSITION FOR INTENSIFICATION BETWEEN SATURDAY NIGHT AND
SUNDAY MORNING AS IT TRACK NORTHEASTWARD ALONG THE EASTERN
SEABOARD. TO FULLY RESPECT THE 19/00Z GEFS/GFS SOLUTION WOULD BE
TO SWIFTLY EJECT THE SYSTEM AWAY FROM THE NORTHEAST. AT THIS
POINT...THE UPSTREAM PATTERN IS DRIVING THIS SOLUTION AND RECENT
TRENDS IN THE GFS/ECMWF AND CANADIAN SUGGEST THERE WILL BE A
SLOWER PROGRESSION OF THE PATTERN THAN WHAT THE 19/00Z GFS
PACKAGES SUGGEST.

THE DAY 4-5 SYSTEM INTENSIFYING OUT WEST IN THE GREAT
BASIN...APPEARS TO EJECT SEVERAL SHORTWAVES NORTHEASTWARD INTO THE
CENTRAL PLAINS...AND THE DETERMINISTIC THICKNESS/TEMPERATURE
FIELDS DO NOT SUPPORT A 'LONE' OR SINGLE (VERTICALLY-STACKED)
CYCLONE. RATHER A COMPLEX 'TROWAL'...AND TRIPLE POINT LOW
STRUCTURE. ONE THAT EJECTS AND INTENSIFIES AN ADDITIONAL SHORTWAVE
AND SURFACE WAVE ACROSS THE SOUTHEAST AND INTO THE CAROLINAS
BETWEEN DAYS 6-7. THE 'TROWAL' STRUCTURE IS DEPICTED ON THE
SURFACE GRAPHICS AS A COMPLEX OCCLUSION...WITH THE PRIMARY WAVE
EMERGING ACROSS THE PIEDMONT REPRESENTING SOMETHING THAT PATTERNS
ITSELF MORE LIKE A NEGATIVELY-TILTED TROUGH.

VOJTESAK
 

[MJO812]

GGEM is less phased than previous runs

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

[mikemurph44]

Negnao, The hpc mentioned favoring the euro ensemble which did not agree with the operational snowstorm run at 0z

[MJO812]

Negnao, The hpc mentioned favoring the euro ensemble which did not agree with the operational snowstorm run at 0z

 

Ukie has  a Sub 995 low just east of the benchmark at 120.

[IsentropicLift]

12z GFS ensemble mean tracks the coastal from off the Delmarva to just south of the benchmark. It's warm.

[mikemurph44]

Ukie has a Sub 995 low just east of the benchmark at 120.

the hpc doesn't even mention the ukmet in their discussion

[IsentropicLift]

GGEM is less phased than previous runs

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

It's all rain.

[PB GFI]

Negnao, The hpc mentioned favoring the euro ensemble which did not agree with the operational snowstorm run at 0z

Where do you see that ?

AH JUST READ HIS PIECE ,

Still like the control , its been spot on for the last 3 weeks

[mikemurph44]

Ukie has a Sub 995 low just east of the benchmark at 120.

rain, there is no cold air, just because a low follows that track does not mean snow when you don't have a cold dome in place

[mikemurph44]

12z GFS ensemble mean tracks the coastal from off the Delmarva to just south of the benchmark. It's warm.

You hit the nail on the head, people see a low on or near the benchmark and say "oh my God it's gonna be a snowstorm!" It doesn't snow when you don't have cold air, which we won't...

[MJO812]

You hit the nail on the head, people see a low on or near the benchmark and say "oh my God it's gonna be a snowstorm!" It doesn't snow when you don't have cold air, which we won't...

 

How do you know we won't? You are talking like the storm is tomorrow. It's  4-5 days out.

[mikemurph44]

what are you basing this on ?

Show me where the cold air is. How is it going to snow without cold air? You would have to rely on the low producing its own cold from massive uvv lifting and dynamic cooling of the column.

[Zir0b]

Show me where the cold air is. How is it going to snow without cold air? You would have to rely on the low producing its own cold from massive uvv lifting and dynamic cooling of the column.

I haven't seen the maps but if the UKMET does indeed have <995 low near the benchmark, that would be similar to the 0Z Euro and I'd imagine the picture would look more wintry 

 

[mikemurph44]

How do you know we won't? You are talking like the storm is tomorrow. It's 4-5 days out.

There is no cold, do you think a cold high/cold air damming is going to magically appear out of nowhere by saturday? Again, you will have to rely on severe uvv lifting and dynamic cooling to create its own cold down to the surface