Nor'easter Brewing for East

[iwantsnow321]

How the GFS has changed! Still a pretty big storm for the east, but a much different setup, and a good bit drier because of it.

Our focus is now all day Wednesday and Thursday morning of next week.

Verbage:
The GFS now takes this system that was coming through TX and the Gulf, and sends it through OK ans straight to the Mid-Atlantic as a relatively moist system for one coming from the due west. It now develops this low as it heads offshore off of the Delmarva, and deepens it as it heads into New England. Overall, a much drier storm for the Mid-Atlantic, and much wetter for New England, as a powerful low develops further off the coast earlier in the week and heads ashore into the Canadian Maritimes.

Graphics:
Our focus now shifts to the 204-240hr time frames.

204hr
216hr
228hr
240hr

QPFs are down for Mid-Atlantic, especially a good bit of PA and WV, and still down a bit for VA, MD, DE, and southern NJ.
Most of New England's have risen, due to the new northward component of the track and the previous low to move onshore in the Tuesday time frame.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_240m.gif

Temps are a larger factor then ever, and it appears as if the majority of the event will be frozen from the Mason-Dixon line northward, possibly a brief rain at the beginning, and moreso of an exception on the coast.
As for these frozen precip amounts, MD, DE, and VA should see about 4" guaranteed snow at this point, the Poconos, most of NJ and eastern NY should see 6-8" frozen, whereas most of New England will see a good bit of rain at the start, swiching over to a decent (12"+?) snowfall, especially in inland Maine.

Two parting words: One, this is an 18Z run which I (like I said) tend not to favor as much as the 00Z and 12Z ones, and two, this is still Days 9 and 10. Plenty can change and these numbers are rather simple approximations from a long-range prediction. Take them rather lightly for the next day or two, until some more experienced forecasters have a chance to analyze the situation.

Windrunner, you didnt mention anything about PA. Will philly be in the 4-6 range with VA, DE and MD?

[wxwatcher91]

Code: Select all

000
FXUS61 KBOX 292107
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
406 PM EST TUE NOV 29 2005

THE CONFIDENCE IN THE FORECAST GOES DOWN CONSIDERABLY IN THE SUNDAY
THROUGH TUESDAY TIME FRAME. ON SUNDAY...A WEAK WAVE IS PROGGED TO
PASS TO OUR SOUTH. THE GFS DOES NOT SHOW ANY QPF IN OUR
REGION...HOWEVER IT DOES SHOW SOME 700 OMEGA WHICH RAISES SOME
CONCERN. IN ADDITION...MID LEVEL FLOW IS A BIT WEST SOUTHWEST SO
THERE COULD BE SOME OVER RUNNING OF THE COLD DOME AT THE SURFACE.
THEREFORE...WILL CARRY LOW CHANCE POPS FOR SOME SNOW
SHOWERS/FLURRIES ON SUNDAY BUT THIS DOESN NOT LOOK SIGNIFICANT.

THINGS TURN EVEN MORE INTERESTING COME MONDAY INTO PART OF TUESDAY.
THE GFS CONTINUES TO INDICATE A POTENTIAL FOR A SIGNIFICANT STORM
SYSTEM FOR SEVERAL RUNS NOW. HOWEVER...EACH RUN DIFFERS ON THE EXACT
TRACK SHOWING THE POTENTIAL FOR AN INLAND RUNNER TO A COASTAL STORM
THAT GRAZES OUR REGION. THE 12Z CANADIAN SHOWS MORE OF AN INLAND
RUNNER WHILE THE 12Z ECMWF SHOWS MORE OF A COASTAL STORM.

WITH ALL THIS SAID...THERE IS PLENTY OF UNCERTAINTY TO WHERE EXACTLY
THIS STORM WILL TRACK. HOWEVER...AT THIS TIME FEEL THAT THE MIDDLE
GROUND IS THE WAY TO GO. A TRUE INLAND RUNNER APPEARS UNLIKELY WITH
LOTS OF COLD AIR THAT OVER THE NORTHERN TIER OF THE U.S. THAT WOULD
TEND TO PREVENT THE STORM FROM MOVING NORTHWARD INTO THE COLD AIR.
IN ADDITION...THE UPPER LEVEL PATTERN APPEARS TO BE MORE AMPLIFIED
AND WITH THE OCEAN STILL SO WARM THAT MIGHT PROVIDE A THERMAL
GRADIENT TO BRING THE STORM UP THE COAST. AS FOR PRECIPITATION
TYPE...MOST AREAS WILL PROBABLY BE COLD ENOUGH TO START AS SNOW. IF
THE STORM TRACKS CLOSER TO THE COAST...SNOW MAY TURN TO ICE ACROSS
THE INTERIOR AND RAIN ALONG THE COAST. OF COURSE...THIS TIME OF YEAR
WITH THE OCEAN TEMPERATURES AROUND 50 IT DOES NOT TAKE MUCH OF AN
EASTERLY COMPONENT TO CHANGE SNOW TO RAIN ON THE COAST.

[krysof]

Code: Select all

000
FXUS61 KBOX 292107
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
406 PM EST TUE NOV 29 2005

THE CONFIDENCE IN THE FORECAST GOES DOWN CONSIDERABLY IN THE SUNDAY
THROUGH TUESDAY TIME FRAME. ON SUNDAY...A WEAK WAVE IS PROGGED TO
PASS TO OUR SOUTH. THE GFS DOES NOT SHOW ANY QPF IN OUR
REGION...HOWEVER IT DOES SHOW SOME 700 OMEGA WHICH RAISES SOME
CONCERN. IN ADDITION...MID LEVEL FLOW IS A BIT WEST SOUTHWEST SO
THERE COULD BE SOME OVER RUNNING OF THE COLD DOME AT THE SURFACE.
THEREFORE...WILL CARRY LOW CHANCE POPS FOR SOME SNOW
SHOWERS/FLURRIES ON SUNDAY BUT THIS DOESN NOT LOOK SIGNIFICANT.

THINGS TURN EVEN MORE INTERESTING COME MONDAY INTO PART OF TUESDAY.
THE GFS CONTINUES TO INDICATE A POTENTIAL FOR A SIGNIFICANT STORM
SYSTEM FOR SEVERAL RUNS NOW. HOWEVER...EACH RUN DIFFERS ON THE EXACT
TRACK SHOWING THE POTENTIAL FOR AN INLAND RUNNER TO A COASTAL STORM
THAT GRAZES OUR REGION. THE 12Z CANADIAN SHOWS MORE OF AN INLAND
RUNNER WHILE THE 12Z ECMWF SHOWS MORE OF A COASTAL STORM.

WITH ALL THIS SAID...THERE IS PLENTY OF UNCERTAINTY TO WHERE EXACTLY
THIS STORM WILL TRACK. HOWEVER...AT THIS TIME FEEL THAT THE MIDDLE
GROUND IS THE WAY TO GO. A TRUE INLAND RUNNER APPEARS UNLIKELY WITH
LOTS OF COLD AIR THAT OVER THE NORTHERN TIER OF THE U.S. THAT WOULD
TEND TO PREVENT THE STORM FROM MOVING NORTHWARD INTO THE COLD AIR.
IN ADDITION...THE UPPER LEVEL PATTERN APPEARS TO BE MORE AMPLIFIED
AND WITH THE OCEAN STILL SO WARM THAT MIGHT PROVIDE A THERMAL
GRADIENT TO BRING THE STORM UP THE COAST. AS FOR PRECIPITATION
TYPE...MOST AREAS WILL PROBABLY BE COLD ENOUGH TO START AS SNOW. IF
THE STORM TRACKS CLOSER TO THE COAST...SNOW MAY TURN TO ICE ACROSS
THE INTERIOR AND RAIN ALONG THE COAST. OF COURSE...THIS TIME OF YEAR
WITH THE OCEAN TEMPERATURES AROUND 50 IT DOES NOT TAKE MUCH OF AN
EASTERLY COMPONENT TO CHANGE SNOW TO RAIN ON THE COAST.

intresting, and that would mean a significant snowfall for me

[WindRunner]

Windrunner, you didnt mention anything about PA. Will philly be in the 4-6 range with VA, DE and MD?

Based on that run, probably a little either side of 6. But that is a "minimum" of frozen precip, and it could be higher, as the freezing line will ultimately determine how much any one place will get.



I'll look at the new model run as soon as they get all of it up, so I should have an update later this evening. So far, it looks like our time frame will be moved up a good bit again.

[WindRunner]

Well, I'd have an update for you now, but the new run of the GFS (18Z 11/29) has a rather strange situation that I feel is very unlikely to occur and I'm not going to waste your time or mine explaining it. I'll just say that it shows warm precip for the entire Mid-Atlantic (PA through VA) coming through at the end of the weekend/early in the week, and a much weaker late-week system that hardly produces any rain at all. If it keeps a similar solution in further runs, I'll talk, but the GFS has proven itself as a rather, well, unsteady model that (as others have said) is known for its flipping, and it's too early to say what this change is.

The 18Z runs for those who want to see it:
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/model_m.shtml

[wxwatcher91]

Well, I'd have an update for you now, but the new run of the GFS (18Z 11/29) has a rather strange situation that I feel is very unlikely to occur and I'm not going to waste your time or mine explaining it. I'll just say that it shows warm precip for the entire Mid-Atlantic (PA through VA) coming through at the end of the weekend/early in the week, and a much weaker late-week system that hardly produces any rain at all. If it keeps a similar solution in further runs, I'll talk, but the GFS has proven itself as a rather, well, unsteady model that (as others have said) is known for its flipping, and it's too early to say what this change is.

The 18Z runs for those who want to see it:
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/model_m.shtml

it appears the last run of the GFS has two separate storms... one around Monday Night and Tuesday (cold and dry)

and another one Friday (warm and wet)

[WindRunner]

Well, the situation appears to have rather dissapated on us at this point, as the 18Z 11/30 GFS develops a rather strong nor'easter that's too far off the coast for any precip anywhere in the Atlantic corridor. At this point, our best chance for snow in the east (Metro areas from NY south to just north of Richmond) is after a system passes us by during the day Monday, probably an inch or two of snow, assuming the ground isn't too wet from the rain beforehand.

Some reference frames from this run:

Sunday/Monday system:

84hrs
90hrs
96hrs
102hrs
108hrs
120hrs

QPFs (mostly rain, don't get excited)
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_p48_120m.gif

The Thursday Miss:
162hrs
168hrs
174hrs
180hrs
192hrs

However, the cold outbreak on Tuesday does appear to be happening at this point, and it appears mid to late week will be rather cold and mostly dry for the east.

As always, remember that models can drasticly change their tune in a relatively short amount of time, and any one solution could get completely thrown out by the time next run comes. In other words, nothing is solidified this far out! Watch this one closely, as this could still change!

[WindRunner]

And this from the Sterling NWS (DC/Balt)

.LONG TERM (THURSDAY NIGHT THROUGH WEDNESDAY)...

AN UPPER LOW WILL MOVE OVER THE NORTHEAST WITH A NEGATIVE TILT AND
ACTIVATE A WEAK SFC LOW OFF THE MID ATL COAST. THAT LOW WILL DEEPEN
AS A SIG STORM FOR NEW ENGLAND AND EASTERN CANADA. AS IT DOES...
COLDER AIR WILL BE DRAGGED IN ON NW WINDS AS 850MB TMPS DROP TO -8C
TO -13C BY FRIDAY EVENING.

HIGH PRES SLIPS BY SATURDAY...THEN A STATIONARY FRONT DEVELOPS OVER
THE REGION FROM THE WEST. LATEST 12Z GFS HAS A DOUBLE SHOT OF RIPPLE
LOW PRES COMING ALONG THAT STALLED FRONT. THE FIRST LOW IS RATHER
WEAK... BUT SLIPS THROUGH OUR S COUNTIES. THE TEMP PROF AT THE
MOMENT APPEARS THAT A MIX OF SNOW AND RAIN WILL FALL LATE SAT INTO
EARLY SUN. SNOW MORE PROB IN THE N... WITH RAIN RATHER LIKELY IN THE
SOUTH. WILL NOT PUT TOO MUCH DETAIL IN THE GRIDS AS THIS IS ALL
LIKELY TO SHIFT BACK AND FORTH A FEW TIMES BEFORE THEN. AT 120HR THE
LATEST GFS HAS A SECOND STRONGER LOW PASSING BY TO OUR S ON MONDAY.
00Z AND OTHER MODELS CERTAINLY GIVE UNCERTAINTY FOR THIS SCENARIO...
SO WILL ONLY HAVE A 30 POP FOR NOW FOR THE SECOND LOW.

TEMPS THROUGH THE EXTENDED WILL RANGE FROM BELOW NORMAL TO MUCH
BELOW NORMAL THROUGH THE EXTENDED.

[WindRunner]

I'll officially call this idea dead now, as the 18Z 12/1 GFS has clear, cold skies for most of the east late Wed into Thurs, and the best nor'easter we'll get will be for central PA north, as a strong low stays a good ways off the coast and brings some precip and cold air to most of New England and surrounding areas. By now, there are enough threads on this other system to keep you up-to-date, so you can most likely consider this the last post on this idea unless some model brings it back over the next couple of days, though that is very unlikely.

[WindRunner]

Turns out that there is still a nice LP center off the coast late week, it's just late Thurs into Fri and doesn't appear to be having much of an effect for most of the east coast, so I'll still let this end assuming the low doesn't move back closer to shore.

[wxwatcher91]

000
FXUS61 KBOX 020955
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
455 AM EST FRI DEC 2 2005

.LONG TERM (SATURDAY THROUGH THURSDAY)...
LATEST MODELS IN DECENT AGREEMENT WITH THE MAIN SYNOPTIC PLAYERS
THROUGH SUNDAY. A LARGE HIGH PRESSURE PUSHES EAST OFF THE COAST OF
THE SOUTHEAST UNTIED STATES. MEANWHILE...THE STAGNANT LOW PRESSURE
OVER QUEBEC AND LABRADOR CONTINUES TO SPIN ITS WHEELS INTO SATURDAY
NIGHT. A FAST MOVING LOW PRESSURE EXPECTED TO ZIP BY TO OUR SOUTH
SUNDAY...BRINGING LIGHT PRECIPITATION TO SOUTHERN NEW ENGLAND.

BEYOND THAT TIME...THERE IS PLENTY OF UNCERTAINTY TO GO AROUND.
01/18Z GFS ENSEMBLES HAD A 4-8 STANDARD DEVIATION VARIANCE FOR MEAN
SEA LEVEL PRESSURE...AS WELL AS A 60-80 M VARIANCE IN 500 MB HEIGHTS
INTO TUESDAY. BOTH THE GFS AND UKMET BRING THE STORM ACROSS OR JUST
INSIDE THE BENCHMARK OF 40N/70W WHICH WOULD RESULT IN A BIG
NOREASTER. THE GGEM AND THE ECMWF KEEP THIS SYSTEM SUPPRESSED FARTHER
TO THE SOUTH AND EAST...WHICH WOULD BE A NEAR MISS. AS A RESULT...
DID NOT CHANGE THE PREVIOUS FORECAST AFTER 12Z MONDAY TO AVOID
SETTING UP A FLIP-FLOP SITUATION WITH THIS POTENTIAL WINTER STORM
MONDAY NIGHT INTO TUESDAY. THE PREVIOUS FORECAST IS RELATIVELY
CONSISTENT WITH THE GFS ENSEMBLE CONSENSUS MEAN.

LATEST GUIDANCE TEMPERATURES LOOKED REASONABLE THROUGH...SO DID NOT
STRAY TOO FAR THROUGH SUNDAY.

[truballer#1]

looking a lot better for I-95. The new 12z GFS came out and it looks very good in the I-95 corridor it shows 1"-1.5" of qpf that could be ova a foot

[wxwatcher91]

The low track across Mississippi and Alabama is the one to be watched.

[WindRunner]

It's definately looking better short term, but the late week event is the one we've been watching, even though it appears it will be the smaller of the two at this time. I'll talk more later. BTW, nice maps wxwatcher!

[Nimbus]

All depends on where the low initializes and how much the high pressure ridge to the east blocks the system.

The later runs seem to have that high moving southeast out of the way rather rapidly. What models are verifying the best currently?

[wxwatcher91]

the models are trending further out to sea...

000
FXUS61 KBOX 031004
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
504 AM EST SAT DEC 3 2005

.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
MODELS CONTINUE TO EXHIBIT GREAT UNCERTAINTY IN THEIR SOLUTIONS
OF A POTENTIAL WINTER STORM MONDAY NIGHT INTO TUESDAY. ALTHOUGH...
MORE MODELS ARE NOW TRENDING THE STORM TRACK FARTHER OUT TO
SEA. EVEN THE 03/00Z GFS ENSEMBLE MEAN IS FOLLOWING THIS TREND.
HOWEVER...AM NOT CONFIDENT ENOUGH TO DROP THE MENTION OF STORM
ENTIRELY. THE 03/00Z UKMET STILL KEEPS THE LOW TRACK CLOSER TO THE
COAST...BUT IT IS NOW A MINORITY OPINION. HPC ALSO OPTING TO KEEP
LOW TRACK A LITTLE TO THE NORTHWEST OF THE 03/00Z GFS TRACK. HAVE
STARTED TO SHIFT THE HEAVIEST PRECIPITATION FARTHER EAST WITH THIS
FORECAST PACKAGE...AND LOWERED SNOW ACCUMULATIONS SLIGHTLY TO AVOID
A POSSIBLE FLIP-FLOP IN THE MODELS. HANDLED TEMPERATURES THE SAME
WAY...BY USING A BLEND OF LATEST GUIDANCE AND PREVIOUS FORECAST.

CURRENT THINKING OF THE SYNOPTIC PATTERN IS TO HAVE THE FAST-MOVING
STORM WELL OUT TO SEA SUNDAY EVENING. WEAK HIGH PRESSURE TAKES
OVER FOR MONDAY. THEN BRINGING A DEVELOPING STORM AROUND THE
BENCHMARK OF 40N/70W LATE MONDAY NIGHT INTO TUESDAY. THIS SYSTEM
DEPARTS TUESDAY AFTERNOON. A COLD FRONT PUSHES TROUGH
WEDNESDAY...FOLLOWED BY A HIGH PRESSURE RIDGE THURSDAY INTO FRIDAY.

SPENT MOST OF MY TIME ON THE POTENTIAL STORM MONDAY NIGHT INTO
TUESDAY...SO NO CHANGES MADE AFTER 00Z WEDNESDAY. SHOULD BE JUST
FINE WITH A STRONG HIGH PRESSURE EXPECTED TO MOVE INTO THE EASTERN
UNITED STATES.

[Lowpressure]

Starting to look more like a Mid Atlantic event i.e. N.C. Mountains, Virginia and Southern MD. Central Virginia looking to be the bullseye.

[krysof]

I'm thinking the snow will extend as far north as northern New Jersey, maybe eastern PA. Long island could also receive heavy amounts of snow.

[truballer#1]

new models just came out and shows it more north!

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_072s.gif

[wxwatcher91]

bumping for update...

on the low track forecast map, the northern track is the first storm (tonight into tomorrow) and the southern one the nor'easter for Monday and Tuesday.