New England Winter 2012-2013

[BigB0882]

We will keep an eye on it. Last time we went to NYC we landed early in the morning and by that night there was a foot of snow! We just made it in time. Maybe this year will be a repeat? If the airmass isn't cold enough then I wont worry, rain shouldn't delay any flights unless there is a ton of wind.

[cycloneye]

Well,if your stay in NYC extends to Christmas,you finnally may see snow and White Christmas as cold air will invade the city by the time another nor'ester moves thru. But caution as this is way ahead in time. (23rd)

[BigB0882]

We are supposed to fly back on the 23rd. LOL! I would love it that moved through a couple of days early, the wedding is on the 21st. I suppose I would rather get stuck IN NYC rather than not being able to get there at all.

[cycloneye]

We are supposed to fly back on the 23rd. LOL! I would love it that moved through a couple of days early, the wedding is on the 21st. I suppose I would rather get stuck IN NYC rather than not being able to get there at all.

Let's see what the models have in the next runs in terms of timing and if snow falls so you can see it I will continue to let you know in the comming days how things stand.

[cycloneye]

The models continue to change in timing and strengh of first low pressure so what I will do is to wait for the long term discussions from the NY NWS to see their thinking. Here is the long term until Sunday.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
408 AM EST MON DEC 10 2012


.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
SOUTHWEST FLOW ALOFT TUESDAY-WEDNESDAY WITH DRY CONDITIONS OVER THE
REGION...AS WEAK LOW PRESSURE SYSTEMS ARE CURRENTLY FORECAST TO STAY
FAR ENOUGH OFFSHORE THIS TIME FRAME TO PREVENT ANY PRECIPITATION
FROM REACHING THE AREA. NAM DOES OUTPUT LIGHT QPF ACROSS SERN
PORTIONS OF THE CWA LATE WED...WITH SOME BACKING FROM A FEW GFS
ENSEMBLE MEMBERS (PROB OF MEASURABLE). HOWEVER...WILL LEAN TOWARD
THE MAJORITY OF GUIDANCE AT THIS TIME...AND KEEP THE FORECAST DRY.

A 700-500 HPA TROUGH CROSSES THE AREA WEDNESDAY NIGHT...BUT WITH
LITTLE MOISTURE TO WORK WITH...CONTINUED A DRY FORECAST.

ZONAL FLOW WITH POSSIBLY SOME WEAK RIDGING BUILDS OVER THE AREA
THURSDAY AND THURSDAY NIGHT.

DIFFERENCES THEN EMERGE BETWEEN THE ECMWF AND GFS FOR THE REMAINDER
OF THE FORECAST...STARTING WITH THE STRENGTH AND TIMING OF A
NORTHERN STREAM SHORTWAVE PASSING TO OUR N FRIDAY...AND THE SFC HIGH
BEHIND IT. GIVEN THE TENDENCY OF THE GFS TO UNDER-DO THE STRENGTH
AND SOUTHERN EXTENT OF HIGHS ORIGINATING IN CANADA...LEANED TOWARDS
THE ECMWF SOLUTION FROM FRIDAY-SUNDAY AS PER PREV FCST.

MAIN IMPACT OF NORTHERN STREAM SHORTWAVE PASSING TO OUR N FRIDAY
NIGHT WILL BE TO DRIVE A COLD FRONT THROUGH...ALLOWING COLDER AIR
TO BUILD IN. WITH A DAMMING HIGH BUILDING IN BY SATURDAY...AND SW
FLOW ALOFT SETTING UP BY LATE SATURDAY - YIELDING AN OVER RUNNING
FLOW SET UP - HAVE SLIGHT CHANCE POPS IN FOR SATURDAY. OVER RUNNING
PRECIPITATION SHOULD BECOME MORE WIDESPREAD SATURDAY
NIGHT/SUNDAY...SO HAVE CHANCE POPS IN THESE PERIODS. APPEARS THAT
THERE COULD BE SUFFICIENT COLD AIR IN THE LOW LEVELS TO SUPPORT AT
LEAST A WINTRY MIX OVER NORTHERN INTERIOR ZONES SATURDAY
NIGHT/SUNDAY MORNING.

AS FOR TEMPERATURES...FOLLOWED A MAV/MET BLEND TUE NIGHT AND WED.
NAM SLIGHTLY COOLER WED DUE TO MORE CLOUD COVER (FURTHER NORTH
SOLUTION WITH SFC LOW).

[BigB0882]

Thanks!

[StormingB81]

Send snow to NC....lol

[cycloneye]

BigB0882,more differences between GFS and ECMWF in terms of timing of next week's nor'easter.That is why I prefer to see the discussions from the NWS offices to see their thinking.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
401 PM EST MON DEC 10 2012

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WEDNESDAY THROUGH SATURDAY IS FORECAST TO BE DRY WITH NEAR NORMAL
TEMPERATURES.

THERE IS GOOD MODEL AGREEMENT WITH A WAVE OF LOW PRES MOVING FAR
OFFSHORE WEDNESDAY THROUGH THURSDAY...GUIDED BY A WEAK POSITIVELY
SLOPED UPPER TROUGH OF LOW PRES. HIGH PRES WILL MOVE SLOWLY EAST
ACROSS THE AREA.

A WEAK COLD FRONT IS FORECAST TO MOVE SE AND PASS S OF THE AREA
FRIDAY NIGHT FOLLOWED BY HIGH PRES BUILDING E ACROSS NEW ENGLAND
THROUGH SATURDAY.

SAT NIGHT THROUGH MONDAY...ALTHOUGH MODELS DO SHOW THE POTENTIAL FOR
A HIGH IMPACT EVENT...THERE ARE LARGE DIFFERENCES IN FORECAST TRACK
THAT WOULD RESULT IN COMPLETELY DIFFERENT SOLUTIONS.

THE EURO MODEL DEVELOPS AN INTENSIFYING LOW OVER THE SE U.S. AND
TRACKS IT N-NE ACROSS NYC EARLY MONDAY THAT WOULD RESULT IN HEAVY
RAIN...STRONG WINDS AND POSSIBLE COASTAL FLOODING.

THE GFS MODEL DEVELOPS A LOW OFF THE COAST THAT DEEPENS RAPIDLY
SOUTHEAST OF THE 40 DEGS N AND 70 DEGS W BENCHMARK THAT WOULD LEAD
TO A COLDER SOLUTIONS WITH CHALLENGING PRECIP TYPE FORECASTS.

FOR THIS FORECAST UPDATE...LEANED TOWARD THE WARMER
EURO/CANADIAN/HPC SOLUTIONS.

IN EITHER CASE...MOISTURE IS FORECAST TO ADVECT EAST RESULTING IN A
CHC OF LIGHT PRECIP AFT MIDNIGHT SATURDAY. THERE IS A CHC FOR LIGHT
FREEZING RAIN WEST AND NORTH OF NYC INCLUDING INTERIOR SW CT THROUGH
AT LEAST SUNDAY MORNING.

STAY TUNED FOR THIS POTENTIAL STORM LATE THIS WEEKEND.


12z GFS at the 18th:



12z ECMWF at the 18th:

[cycloneye]

Doesn't look good for snow on the 17th but still changes can occur.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
501 AM EST TUE DEC 11 2012


.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS IN GOOD AGREEMENT THRU SAT SO A BLEND WAS USED.

A 1030 HIGH WILL SETTLE OVER THE REGION FOR THU...THEN GRADUALLY
MODIFY AND GET SUPPRESSED TO THE S BY A SHRTWV RACING ACROSS CANADA
ON FRI. THIS WILL RESULT IN DRY WEATHER THRU THE PERIOD. SEASONAL
TEMPS ON THU WILL GIVE WAY TO A SLIGHT WARMUP ON FRI. LARGE DIURNAL
SPREADS CAN BE EXPECTED DUE TO MAINLY CLEAR SKIES AND LGT WINDS.

A COLD FRONT LATE FRI NGT INTO SAT WILL REINFORCE COOLER TEMPS FOR
SAT. GULF AND ATLANTIC MOISTURE WILL BE CUTOFF BY THE HIGH TO THE
S...SO A DRY FROPA IS EXPECTED.

H5 PACIFIC LOW THEN TRAVERSES THE COUNTRY AND BEGINS TO ADVECT GULF
MOISTURE INTO THE REGION SAT NGT INTO SUN. WITH COLD AIR IN
PLACE...A PERIOD OF SNOW OR MIXED PCPN WILL BE POSSIBLE...ESPECIALLY
ACROSS THE INTERIOR...SAT NGT INTO SUN MRNG. SIGNIFICANT CHANGES
HAVE NOT BEEN MADE TO THE OFFICIAL FCST AT THIS JUNCTURE...BUT THE
ECMWF HAS TRENDED COOLER WITH THE SYSTEM...KEEPING THE WARM FRONT
INVOF THE NRN HALF OF THE CWA. WAA ALOFT WILL ELIMINATE SNOW CHANCES
BY SUN AFTN AND SUN NGT BASED ON THE LATEST PROGS...BUT SOME
SLEET/FZRA MIX WILL BE POSSIBLE ACROSS THE INTERIOR IF THE WARM
FRONT DOES NOT CLEAR THE CWA. THE SYSTEM EXITS ON MON WITH PCPN
ENDING AND SEASONALLY COOL TEMPS. BOTH THE 00Z GFS AND ECMWF HAVE
BACKED OFF ON DEEP CYCLOGENESIS WITH THIS SYSTEM. IT IS STILL TOO
EARLY TO DISCOUNT THIS POSSIBILITY HOWEVER. A NUMBER OF THE GFS
ENSEMBLE MEMBERS PLACE MID-UPR 980S LOWS INVOF THE BENCHMARK AT SOME
POINT SUN/MON. ONE OF THE MEMBERS PLACES A 979 LOW OVER BOSTON 18Z
MON.

[BigB0882]

Thanks for the updates. I would love some snow but I'd rather everyone arrive to NYC safely. I just hope it isn't cold and raining. That's always miserable.

[cycloneye]

BigB0882,check the 12z GFS Loop below and you see three nor'easters between the 17th and Christmas day swinging thru but the most strongest one is the second that throws snow to NC and VA but leaves only flurries for NYC. Let's see if there are more changes in next runs. StormingB81,there is your snow.

http://mag.ncep.noaa.gov/NCOMAGWEB/appc ... mageSize=M

[cycloneye]

12z ECMWF is like GFS showing a big nor'easter on the 20th but is off the coast.

[Ntxw]

The mid-Atlantic may not be good for snow without the cold air pipe, but you folks in New England are never out of supply with that . Will be fun to follow what you guys see up there, good potential for a major event!

[BigB0882]

Well that big one off the coast could easily end up in a different location so I will keep a close eye on it.

[cycloneye]

Well that big one off the coast could easily end up in a different location so I will keep a close eye on it.

Here is this afternoon long term discussion. I highlighted in blue the part that you want to know as it falls on the 18th.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
317 PM EST TUE DEC 11 2012


LONG TERM /THURSDAY THROUGH MONDAY/...
LARGE INLAND HIGH PRESSURE SYSTEM EXTENDING OVER THE AREA ON THU
WILL SINK SLOWLY SOUTH/EAST FRI INTO SAT...AS IT ALIGNS WITH A
DEVELOPING BROAD UPPER RIDGE OVER THE SOUTHEAST STATES. SKIES SHOULD
BE MOSTLY CLEAR DURING MUCH OF THIS TIME...WITH NEAR AVG TEMPS ON
THU MODERATING TO SLIGHTLY ABOVE AVG FRI-SAT AS H8-10 THICKNESSES
INCREASE IN RESPONSE TO THE UPPER RIDGING TO THE SOUTH...AND AS A
W-SW RETURN FLOW DEVELOPS ON THE NORTHERN FLANK OF THE SFC HIGH.
CLOUDS SHOULD INCREASE SOMEWHAT SAT AFTERNOON WELL IN ADVANCE OF LOW
PRESSURE ENTERING THE MID MISSISSIPPI VALLEY...WHILE AT THE SAME
TIME HIGH PRESSURE BUILDING S FROM ERN CANADA INTO NEW ENGLAND
FORCES A BACK DOOR COLD FRONT JUST TO OUR SOUTH SAT NIGHT.
ASSOCIATED WEDGE OF COLDER LOW LEVEL AIR COULD MAKE FOR COMPLICATED
P-TYPE INLAND LATE SAT NIGHT INTO SUNDAY MORNING AS THE LOW MOVES
INTO THE GREAT LAKES...AND PRECIP WITH A LEADING WARM FRONT ARRIVES.
GFS IS MORE AGGRESSIVE THAN ECMWF WITH H8 WARMING ON SUNDAY...BUT
EVEN THE ECMWF SHOWS SOME EVENTUAL H9 WARMING...SO P-TYPE WILL BE
DRIVEN BY THIS AND AMT OF SFC WARMING THAT MANAGES TO TAKE PLACE IN
THE PRESENCE OF COLD AIR DAMMING. HAVE FCST MAINLY SNOW INLAND TO
START LATE SAT NIGHT INTO SUNDAY MORNING...WITH SOME AREAS OF
FREEZING RAIN POSSIBLY INLAND NW OF NYC METRO SUNDAY MORNING AS WARM
AIR STARTS TO INTRUDE...FOLLOWED BY ENOUGH DEEP LAYER WARMING FOR
PLAIN RAIN THROUGHOUT SUNDAY AFTERNOON. COULD AGAIN SEE MIXED
PRECIP OR A CHANGE BACK TO SNOW INLAND SUNDAY NIGHT...ESPECIALLY
IN THE HIGHER ELEVATIONS...AS BOUNDARY LAYER COOLS OFF AND AS A
SECONDARY LOW DEVELOPS TO THE SOUTH.

THE SECONDARY SHOULD TAKE MOST OF THE HIGH/MID LEVEL MOISTURE WITH
IT AS IT PASSES TO THE E MON MORNING...LEAVING ONLY A 20-30 PERCENT
CHANCE OF SOME LIGHT RAIN OR SNOW SHOWERS FOR MON INTO MON NIGHT.
COULD SEE ADDITIONAL CHANCES FOR SOME LIGHT PRECIP ON TUE AS AN
UPPER LEVEL TROUGH AND WEAK SFC TROUGH REFLECTION APPROACH FROM THE
WEST. ECMWF MANAGES TO PHASE A SRN STREAM DISTURBANCE WITH THIS
TROUGH...INDUCING SFC CYCLOGENESIS OFF THE SRN MID ATLANTIC COAST
THAT WOULD BRING MORE WIDESPREAD PRECIP ON TUE ESPECIALLY OUT
EAST...BUT CONFIDENCE IN THIS SOLUTION IS VERY LOW GIVEN LACK OF RUN
TO RUN CONTINUITY AND LACK OF GEFS SUPPORT.

[cycloneye]

Here is the latest long term discission for NYC:


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
637 AM EST WED DEC 12 2012

LONG TERM /SATURDAY THROUGH TUESDAY/...
A LARGE AREA OF HIGH PRESSURE AND SLIGHT UPPER RIDGING REMAINS OVER
THE AREA ON SATURDAY AND SINKS SOUTH EARLY SUNDAY. GLOBAL MODELS IN
GOOD AGREEMENT ON THE APPROACH OF THE INITIAL LOW PRESSURE SYSTEM ON
SUNDAY WITH CLOUD COVER INCREASING. A WARM FRONT MOVES NORTH NEAR
THE AREA ON SUNDAY WITH LIGHT PRECIP BEGINNING EARLY SUNDAY MORNING.
WITH A HIGH TO THE NORTH OF THE AREA...MODELS ARE SHOWING SOME
LINGERING COLD AIR ON SUNDAY MORNING DUE TO HIGH PRESSURE TO THE
NORTH. AS THE WARM FRONT NUDGES NORTH...EXPECT SNOW INITIALLY INLAND
WITH RAIN/SNOW ELSEWHERE. IF THE WARM AIR MAKES IT IN ALOFT
BEFORE THE SURFACE WARMS...COULD SEE A VERY BRIEF PERIOD OF
FREEZING RAIN IN AREAS WELL NORTH AND WEST OF NYC...BUT TOO EARLY
TO SAY WITH CERTAINTY ON THE TIMING OR AMOUNT.

SUNDAY IS WHERE THE ECMWF/GEFS/GFS START TO DIVERGE ON THE OVERALL
PATTERN AND THE RESULTING PRECIP TYPE FOR SUNDAY. GFS IS SHOWING A
SECONDARY LOW DEVELOPING JUST SOUTHEAST OF LONG ISLAND AND MOVING
NORTHEAST. THIS SOLUTION COULD BRING IN MORE COLD AIR TO THE REGION
AND ALLOW FOR MORE OF THE AREA TO SEE SNOW. RIGHT NOW...WENT WITH A
CONSERVATIVE APPROACH AND LEFT IT ALL RAIN ON SUNDAY FOR MUCH OF THE
AREA OUTSIDE OF ORANGE/PUTNAM COUNTIES WHERE IT IS FORECAST TO BE
ALL SNOW. THE ECMWF IS DIGGING AN UPPER TROUGH DEEP INTO THE
SOUTHERN STATES WITH A RESULTING SURFACE LOW DEVELOPING NEAR THE
SOUTHEAST STATES MONDAY MORNING...STRENGTHENING OFF THE JERSEY COAST
AND TRACKING JUST OFF MONTAUK POINT MONDAY NIGHT. THIS TRACK WOULD
RESULT IN A MOSTLY RAIN EVENT AS IS FORECAST. GEFS MEAN IS SIMILAR
TO ECMWF BUT WITH A MORE NORTHERN TRACK OF THE SURFACE LOW.

TUESDAY NIGHT...GFS/ECMWF SIMILAR IN SHOWING ANOTHER UPPER TROUGH
DIGGING INTO THE SOUTHEAST STATES AND WITH A STRONG COASTAL LOW
DEVELOPING OF THE NORTH CAROLINA COAST AND THEN TRACKING VERY NEAR
THE 40N/70W BENCHMARK. THE BOUNDARY LAYER IS STILL WARM FOR THIS
EVENT BUT THE AREA COULD STILL SEE SNOW DEPENDING ON THE EVENTUAL
STRENGTH AND TRACK OF THE SYSTEM.

TEMPERATURES WILL BE NEAR NORMAL THROUGH THE LONG TERM PERIOD BUT
WILL DEPEND LARGELY ON THE TRACK OF THE LOW PRESSURE AREAS FORECAST
TO DEVELOP. ON SUNDAY...IF THE SECONDARY DOES NOT DEVELOP SOUTHEAST
OF LONG ISLAND AS THE GFS IS SHOWING...TEMPS COULD BE A DEGREE OR
TWO WARMER THAN FORECAST. IF THE LOW DOES FORM...COULD BE A BIT
COOLER.

[BigB0882]

Thanks again. Still a wait and see game!

[StormingB81]

Hopefully that stays in the forecast

BigB0882,check the 12z GFS Loop below and you see three nor'easters between the 17th and Christmas day swinging thru but the most strongest one is the second that throws snow to NC and VA but leaves only flurries for NYC. Let's see if there are more changes in next runs. StormingB81,there is your snow.

http://mag.ncep.noaa.gov/NCOMAGWEB/appc ... mageSize=M

[[/i]

[cycloneye]

Thanks again. Still a wait and see game!

You are right about still a wait and see game as GFS is weaker than Euro that bombs the nor'easter and with one day of difference.

12z GFS on the 19th.



12z Euro on the 20th.

[cycloneye]

They add the word uncertainty to the afternoon discussion and that means more model watching and more looking for clarity of things.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
333 PM EST WED DEC 12 2012

LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE OVER THE AREA FRIDAY SLOWLY MOVES OFFSHORE...AND THEN
DEPARTS ON SATURDAY. DRY WEATHER ON TAP FOR THE END OF THE WORK WEEK
AND START OF THE WEEKEND WITH TEMPS RUNNING ABOUT 5 DEGREES ABOVE
NORMAL WITH HIGHS IN THE MID TO UPPER 40S ACROSS MOST OF THE CWA AND
AROUND 50 IN/AROUND NYC.

STARTING ON SUNDAY...A PROLONGED PERIOD OF UNSETTLED WEATHER IS ON
TAP FOR THE AREA THROUGH THE MIDDLE OF NEXT WEEK. THE MODELS HAVE
DIVERGING SOLUTIONS AS TO WHAT IS GOING TO HAPPEN AND WHEN IT WILL
HAPPEN.

HIGH PRES BUILDS INTO EASTERN CANADA SATURDAY NIGHT AS LOW PRES
MOVES INTO THE GREAT LAKES. A WARM FRONT AHEAD OF THE LOW PUSHES
TOWARDS THE NORTHEAST ON SUNDAY. WINTRY PRECIP LIKELY FOR THE
INTERIOR AND LONG ISLAND SATURDAY NIGHT...CHANGING OVER TO PLAIN
RAIN SUNDAY AS THE WARM FRONT LIFTS NORTH THOUGH THE REGION AND
TEMPS WARM INTO THE 40S. TOO SOON TO DETERMINE HOW MUCH SNOW/ICE
ACCUMULATION WOULD FALL. THE PARENT LOW MOVES INTO CANADA...BUT A
WEAK SECONDARY LOW WILL FORM OVER THE DELMARVA AREA SUNDAY NIGHT...
AND WILL DEPART ON MONDAY.

FROM THERE...A DEEP MID-LEVEL TROUGH DIGS INTO THE CENTRAL PLAINS ON
MONDAY. THIS IS WHERE THE MODELS DIVERGE. THE ECMWF HAS A COASTAL
PASS SOUTH OF LONG ISLAND LATE MONDAY...WHEREAS THE GFS HOLDS OFF ON
THAT LOW UNTIL LATE MONDAY NIGHT/TUESDAY. THE GFS THEN HAS THAT LOW
DEPART TUESDAY NIGHT...AND THE ECMWF BRINGS ANOTHER COASTAL LOW TO
THE REGION ON WEDNESDAY.

BASED ON THE POSITIONING OF THESE SYSTEMS...LOOKS LIKE ENOUGH WARM
AIR WILL SURGE INTO THE REGION TO KEEP PRECIP RAIN...AT LEAST DURING
THE DAY. AT NIGHT...TEMPS WOULD BE COLD ENOUGH TO SUPPORT SNOW OR A
RAIN/SNOW MIX. HIGH UNCERTAINTY AT THIS TIME...SO WILL CARRY CHANCE
POPS THROUGH THE FORECAST PERIOD. DUE TO THE HIGH LEVELS OF
UNCERTAINTY...FOLLOWED HPC GUIDANCE FOR THE LONG TERM PERIOD.