Mega Nor'easter slams NE States: Web Cams from area posted

[srainhoutx]

Updated morning Prelim Disco is starting the stepping back and caution mode...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
859 AM EST WED DEC 22 2010

VALID 12Z SUN DEC 26 2010 - 12Z WED DEC 29 2010


...HIGH UNCERTAINTY WITH TRACK/IMPACT OF POWERFUL EAST
COAST/WESTERN ATLANTIC STORM SUN-MON...

AN AMPLIFIED ERN PAC TROF AND SHARPENING W-CNTRL NOAM RIDGE IN
PLACE AT THE START OF THE MEDIUM RANGE PERIOD EARLY SAT WILL
SUPPORT FURTHER DEEPENING OF AN EVOLVING ERN CONUS TROF THAT
SHOULD REACH THE EAST COAST AROUND DAY 5 MON. UPSTREAM FLOW
SHOULD TREND FLATTER WITH TIME AS ERN PAC TROF ENERGY LIFTS NEWD
INTO THE WEST BY SUN-MON AND CONTINUE EWD THEREAFTER... WHILE
ADDITIONAL ERN PAC ENERGY WITH GENERALLY MODEST AMPLITUDE
CONTINUES TOWARD/INTO THE WEST. THIS LOWER AMPLITUDE WRN FLOW IS
EXPECTED TO KICK OUT THE DEEP ERN TROF BY TUE-WED.

OPERATIONAL MODELS AND ENSEMBLES CONTINUE TO SHOW CONSIDERABLE
SPREAD WITH THE TRACK OF THE SYSTEM FCST TO DEEPEN AS IT TRACKS
FROM THE GULF COAST OR GULF OF MEXICO INTO THE WRN ATLC OR ALONG
THE EAST COAST. THE PAST 2-3 OPERATIONAL ECMWF RUNS HAVE
INDICATED A MASSIVE...DEEP...SLOW-MOVING CYCLONE HUGGING THE
CAROLINA AND MID ATLANTIC COASTS THE TWO DAYS FOLLOWING CHRISTMAS.
THE ECMWF AND UKMET WERE THE FIRST OF THE GLOBAL MODELS TO SWITCH
FROM TRACKING THIS WAVE ALONG 40N THROUGH THE MIDWEST...TO A
SUPPRESSED PATH ACROSS THE DEEP SOUTH. SINCE THIS ADJUSTMENT...
THE UKMET TRENDED EVEN FARTHER SOUTH...WITH THE ECMWF LOCKING ONTO
AN EVOLUTION THAT TAKES THE DEVELOPING LOW TO THE FLORIDA
PANHANDLE AND THEN SHARPLY UP THE EASTERN SEABOARD. THE 06Z GFS
HAS ALSO TRENDED TO A VERY SUPPRESSED SOLN ACROSS THE GULF...
ADDING SUPPORT FOR SUCH A SCENARIO FOR AT LEAST THAT PART OF THE
FCST.

THE TRACK OF THIS SYSTEM BEYOND THE GULF REGION STILL DEPENDS
HEAVILY ON SHRTWV DETAILS OF NRN STREAM FLOW... WITH WHICH MODELS
SOMETIMES HAVE CONSIDERABLE DIFFICULTY UNTIL WITHIN A COUPLE DAYS
OF THE VALID TIME. OF PARTICULAR NOTE THE 00Z/06Z GFS ARE ON THE
SHARP/WWD ELONGATED SIDE OF THE FULL GUIDANCE SPREAD WITH ENERGY
OVER THE WRN GRTLKS/UPR MS VLY AS OF EARLY DAY 4 SUN. THIS
ORIENTATION OF FLOW LIKELY PLAYS A PART IN THOSE GFS RUNS TRACKING
THE DEEPENING WRN ATLC SFC LOW WELL OFF THE COAST. THE 00Z
GEFS/ECMWF ENSEMBLE MEANS OFFER MORE SUPPORT FOR A SHARPER AND
MORE N-S ORIENTED TROF THAN RECENT GFS RUNS. WHILE THE 00Z AND
12Z/21 ECMWF EVOLUTIONS ARE FAIRLY EXTREME WITH THE DEPTH OF THE
MID LVL LOW THAT CLOSES OFF NEAR THE EAST COAST... THEY APPEAR A
LITTLE MORE COMPATIBLE WITH ENSEMBLE MEAN IDEAS VERSUS GFS RUNS.
AS THE LOW TRACKS ALONG THE EAST COAST THE 00Z ECMWF IS ON THE WRN
SIDE OF THE SPREAD OF 00Z ECMWF ENSEMBLE MEMBERS AND WWD OF ALL
00Z GEFS MEMBERS WHICH ARE ADMITTEDLY SOMEWHAT LOWER IN
RESOLUTION. WHILE THE STRONG DYNAMICS ALOFT MAY WELL SUPPORT THE
OPERATIONAL ECMWF SOLN... IT IS TOO EARLY TO SUBSCRIBE FULLY TO
ITS FCST. A SOLN IN THE WRN HALF OF THE GUIDANCE SPREAD STILL
APPEARS REASONABLE THOUGH. AS A RESULT WILL GO WITH A BLEND
CONSISTING OF 30 PCT EACH 00Z ECMWF AND 12Z/21 ECMWF RUNS WITH THE
REMAINING 40 PCT OCCUPIED BY THE 00Z ECMWF ENSEMBLE MEAN.

THE PREFERRED BLEND FOR THE ERN CONUS/WRN ATLC EVOLUTION TONES
DOWN THE 00Z ECMWF THAT IS ON THE SHARP/AMPLIFIED SIDE OF THE
ENVELOPE WITH THE MID LVL TROF ENTERING THE WEST ON DAY 4 SUN.
CONFIDENCE IN PARTICULARS OF ERN PAC TO PLAINS/GRTLKS FLOW
DECREASES AS AMPLITUDE OF THE MEAN FLOW LIKEWISE DECREASES. BY
DAY 7 WED THE MOST COMMON IDEAS OF ENSEMBLE MEANS ARE TOWARD A
WEAK SHRTWV REACHING THE GRTLKS AND VICINITY... A SHRTWV TROF
NEARING THE WEST COAST... AND A MODERATE TROF REACHING NWRN
MEXICO. ECMWF RUNS FIT THE ENSEMBLE MEANS BETTER THAN THE 00Z/06Z
GFS WHICH APPEAR SOME WHAT SLOW. EXPECT SOME LOCALLY MDT-HVY PCPN
OVER CNTRL-NRN CA DURING THE FIRST HALF OF THE PERIOD WITH THE
LEADING TROF EJECTING INTO THE WEST. EXPECT A DRIER PERIOD ALONG
THE SRN HALF OF THE WEST COAST MON-TUE... BUT THE DAY 7 SHRTWV MAY
PUSH PCPN SWD AGAIN BY NEXT WED.

RAUSCH/CISCO

[Ntxw]

A worrisome thing that I do have for those wishing this storm will bomb at the right place is that the Euro no longer has full support from it's ensembles. They as a consensus has it too far south and east overall.

[cycloneye]

Steve,I put again this=? at the title after that discussion by HPC.Let's see what the 12z package of models shows.

[Ntxw]

Steve,I put again this=? at the title after that discussion by HPC.Let's see what brings the 12z package of models.

GFS has quite a bomb unlike it's previous runs. It's a good sign that it has the monster, just a matter of where it tracks, close enough for adjustments. That thing has pressures comparable to hurricanes lol wow.

[srainhoutx]

The 12Z GFS certainly is a big step toward a sensible solution. The -NAO is key here folks. We often see in a transitory period of rising AO NAO periods some crazy jogs in numerical guidance. Let's see what the rest of the 12Z runs offer, but this is a positive step to a consensus, IMO.

[cycloneye]

Yes,12z GFS is much more closer to ECMWF on the track.

[cycloneye]

The 12z GFS does not have a block to the storm as it moves pretty fast,different from EURO that is slower.

[northjaxpro]

The 12z GFS does not have a block to the storm as it moves pretty fast,different from EURO that is slower.

Yeah, for most of this week the GFS had been the outlier, now it has finally come in line with the Euro playing catch up. The latest Euro runs do still have the system moving slower, so we will see if the GFS will trend slower in its motion in future runs.

[cycloneye]

12z CMC is fast as GFS.

http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[srainhoutx]

Another big hit coming from the Euro.

[cycloneye]

One word on the 12z EURO=EPIC!!

[northjaxpro]

One word on the 12z EURO=EPIC!!

WOW! Look at the massive size of that storm! If the Euro is spot on, this storm really really could be one for the ages folks!

[srainhoutx]

Some earlier estimates would suggest a crippling storm along the I-95 Corridor with 20-30 inches of snow and winds offshore near Hurricane force.

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

[Portastorm]

I've seen some references to March 1993 from some pro mets on other forums. This could indeed be one for the ages.

[cycloneye]

This afternoon's HPC discussion is still not buying completly the EURO scenario.

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
217 PM EST WED DEC 22 2010

VALID 12Z SAT DEC 25 2010 - 12Z WED DEC 29 2010


...CONTINUED HIGH UNCERTAINTY WITH TRACK/IMPACT OF POWERFUL EAST
COAST/WESTERN ATLANTIC STORM SUN-MON...

AN AMPLIFIED ERN PAC TROF AND SHARPENING W-CNTRL NOAM RIDGE IN
PLACE AT THE START OF THE MEDIUM RANGE PERIOD EARLY SAT WILL
SUPPORT FURTHER DEEPENING OF AN EVOLVING ERN CONUS TROF WHOSE AXIS
SHOULD REACH THE EAST COAST AROUND DAY 5 MON. UPSTREAM FLOW
SHOULD TREND FLATTER WITH TIME AS ERN PAC TROF ENERGY LIFTS NEWD
INTO THE WEST BY SUN-MON AND CONTINUES EWD THEREAFTER... WHILE
ADDITIONAL ERN PAC ENERGY WITH GENERALLY MODEST AMPLITUDE
CONTINUES TOWARD/INTO THE WEST. THIS LOWER AMPLITUDE WRN FLOW IS
EXPECTED TO KICK OUT THE DEEP ERN TROF BY TUE-WED.


OPERATIONAL MODELS AND ENSEMBLES CONTINUE TO SHOW CONSIDERABLE
SPREAD WITH THE TRACK OF THE SYSTEM FCST TO DEEPEN AS IT TRACKS
FROM THE GULF COAST OR GULF OF MEXICO INTO THE WRN ATLC OR ALONG
THE EAST COAST. THE PAST 2-3 OPERATIONAL ECMWF RUNS HAVE
INDICATED A MASSIVE...DEEP...SLOW-MOVING CYCLONE HUGGING THE
CAROLINA AND MID ATLANTIC COASTS THE TWO DAYS FOLLOWING CHRISTMAS.
THE ECMWF AND UKMET WERE THE FIRST OF THE GLOBAL MODELS TO SWITCH
FROM TRACKING THIS WAVE ALONG 40N THROUGH THE MIDWEST...TO A
SUPPRESSED PATH ACROSS THE DEEP SOUTH. SINCE THIS ADJUSTMENT...
THE UKMET TRENDED EVEN FARTHER SOUTH...WITH THE ECMWF LOCKING ONTO
AN EVOLUTION THAT TAKES THE DEVELOPING LOW TO THE FLORIDA
PANHANDLE AND THEN SHARPLY UP THE EASTERN SEABOARD. THE 06Z GFS
HAS ALSO TRENDED TO A VERY SUPPRESSED SOLN ACROSS THE GULF...
ADDING SUPPORT FOR SUCH A SCENARIO FOR AT LEAST THAT PART OF THE
FCST.

THE TRACK OF THIS SYSTEM BEYOND THE GULF REGION STILL DEPENDS
HEAVILY ON SHRTWV DETAILS OF NRN STREAM FLOW THAT ORIGINATES AT
MID TO HIGHER LATITUDES. MODELS SOMETIMES HAVE CONSIDERABLE
DIFFICULTY WITH HANDLING HIGHER LATITUDE ENERGY UNTIL WITHIN A
COUPLE DAYS OF AN EVENT. OF PARTICULAR NOTE THE 00Z/06Z GFS ARE
ON THE SHARP/WWD ELONGATED SIDE OF THE FULL GUIDANCE SPREAD WITH
ENERGY OVER THE WRN GRTLKS/UPR MS VLY AS OF EARLY DAY 4 SUN. THIS
ORIENTATION OF FLOW LIKELY PLAYS A PART IN THOSE GFS RUNS TRACKING
THE DEEPENING WRN ATLC SFC LOW WELL OFF THE COAST. THE 00Z
GEFS/ECMWF ENSEMBLE MEANS OFFER MORE SUPPORT FOR A SHARPER AND
MORE N-S ORIENTED TROF THAN RECENT GFS RUNS. MEANWHILE THE PAST
TWO ECMWF RUNS ARE QUITE DIFFERENT WITH THEIR HANDLING OF A CLOSED
LOW TO THE E OF HUDSON BAY AS OF DAY 3 SAT... SO THE ECMWF ALSO
HAS QUESTION MARKS EVEN THOUGH THEIR RUNS ARE MORE SIMILAR FARTHER
SWD.

AS THE SFC LOW TRACKS NEAR THE EAST COAST THE 00Z ECMWF IS ON THE
WRN SIDE OF THE SPREAD OF 00Z ECMWF ENSEMBLE MEMBERS AND WWD OF
ALL 00Z GEFS MEMBERS WHICH ARE ADMITTEDLY SOMEWHAT LOWER IN
RESOLUTION. THIS CORRESPONDS TO THE OPERATIONAL ECMWF RUNS BEING
A DEEP EXTREME WITH THE CLOSED LOW ALOFT. ASIDE FROM THE DEPTH
ALOFT THE ECMWF MID LVL EVOLUTION DOES APPEAR SOMEWHAT MORE
COMPATIBLE WITH GEFS/ECMWF ENSEMBLE MEAN IDEAS THAN THE 00Z/06Z
GFS. THUS PREFER A SFC SOLN IN THE WRN HALF OF THE GUIDANCE
SPREAD AND CLOSER TO THE ECMWF THAN 00Z/06Z GFS... BUT IT IS TOO
EARLY TO SUBSCRIBE FULLY TO THE 00Z ECMWF SPECIFICS. THUS WILL
PREFER A BLEND CONSISTING OF 30 PCT EACH 00Z ECMWF AND 12Z/21
ECMWF RUNS WITH THE REMAINING 40 PCT OCCUPIED BY THE 00Z ECMWF
ENSEMBLE MEAN TO YIELD A COMPROMISE AROUND 2/3 TOWARD THE ECMWF.

AS FOR SENSIBLE WEATHER IMPACT... THERE WILL LIKELY BE A TIGHT
SNOWFALL GRADIENT ALONG/INLAND FROM THE EAST COAST... MAKING IT
DIFFICULT TO DETERMINE AS FAR IN ADVANCE AS MAY BE DESIRED WHICH
AREAS WILL RECEIVE SNOW AND HOW MUCH WILL ACCUMULATE AT A
PARTICULAR LOCATION. HOWEVER EVEN WHERE THERE IS LITTLE OR NO
SNOW THERE SHOULD BE A PERIOD OF BREEZY/WINDY CONDS OVER THE ERN
STATES. THIS SYSTEM WILL BE TRAILED BY ANOTHER SIGNIFICANT SURGE
OF COLD AIR INTO THE EAST WITH SOME DAYTIME READINGS REACHING AT
LEAST 15 F BELOW NORMAL SUN-MON... AND FREEZING TEMPS FOR LOWS
EXTENDING INTO THE NRN FL PENINSULA BY EARLY MON-TUE.

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

[northjaxpro]

I remember the March '93 Superstorm so well. That system was unbelievably impressive in the way everything came together dynamically for so very late in the winter season. I always have wondered or even imagined what more severe impacts could happen if such a massive storm was to occur during the coldest portion of the winter season.

The fact that the models are now gaining more consensus of another potential mega storm developing over this holiday weekend is to me almost utterly astonishing! There is a potential that this system may even surpass the effects of the March '93 Superstorm in that the models are showing a 1035 mb Arctic High Pressure dome to drop straight down from the polar regions directly behind this storm. That is some very cold arctic air progged to come down and I have a hunch that snowfall totals up and down the Eastern US seaboard by early next week could reach historic proportions if the Euro runs pan out.

[cycloneye]

Afternoon discussion by NWS in Wakefield,VA.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
224 PM EST WED DEC 22 2010

.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM MOVES OFF THE NORTH CAROLINA COAST THIS
AFTERNOON...ALLOWING HIGH PRESSURE TO BUILD BACK ACROSS THE AREA
THIS EVENING THROUGH FRIDAY. LOW PRESSURE WILL DEVELOP OVER THE
GULF OF MEXICO FRIDAY NIGHT AND SATURDAY...AND WILL TRACK OFF THE
SOUTHEAST UNITED STATES COAST SATURDAY NIGHT. THE LOW IS EXPECTED
TO INTENSIFY WHILE MOVING UP THE EAST COAST ON SUNDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LATEST 00Z SUITE OF MODELS...GFS/ECMWF HAVE STAYED SIMILAR TO
THEIR PREV RUNS...THE GGEM HAS BECOME MORE LIKE THE FLATTER/WEAKER/MORE
SUPPRESSED GFS...WHILE THE UKMET REMAINS MORE LIKE THE ECMWF (SEE
LATEST PREEPD FROM HPC FOR DETAILS). ONE CHANGE IS THAT EVEN THE
WEAKER SOLN OF THE GFS/GGEM ARE SLOWER IN THE TRACK...AND HAVE
SCALED BACK A BIT FURTHER ON PRECIP CHANCES FOR SAT...PARTICULARLY
DURING THE MRNG AND OVER THE ERN SHORE. ANYTHING THAT DOES FALL
SAT/CHRISTMAS DAY LOOKS TO BE FAIRLY LIGHT DUE TO MAIN FORCING
REMAINING SEVERAL HUNDRED MILES TO OUR SOUTH AND WEAK SFC HIGH
PRESSURE STILL NOSING DOWN FROM THE UPR MIDWEST. OTHER THAN THE
SLOWER TIMING...DID NOT CHANGE THINKING FROM PREV FCST VERY MUCH.
THE MODEL DIFFERENCES ARE LIKELY DUE TO INTERACTIONS WITH THE
AMPLIFYING UPR PATTERN OVER THE CENTRAL CONUS (ECMWF MORE
AGGRESSIVE)...AS WELL AS WITH THE NORTH ATLANTIC BLOCKING LOW. THE
ECMWF FILLS IN/WEAKENS THIS LATTER FEATURE A BIT SLOWER THAN THE
GFS SOLUTION...WHICH IS MORE PROGRESSIVE AND HENCE...SIGNIFICANTLY
MORE ZONAL (LESS AMPLIFIED) WITH THE UPPER LONGWAVE PATTERN THAN
MOST ALL OTHER DETERMINISTIC GUIDANCE. AS SUCH...GIVEN THE STRONG
AND PERSISTENT -NAO AND AFOREMENTIONED BLOCKING PATTERN IN
PLACE...A BLEND TOWARDS THE SLOWER MORE AMPLIFIED SOLNS MAKE MORE
SENSE. FCST WILL FOLLOW A MODEL BLEND...BUT WEIGHTED MORE TWDS THE
MORE AMPLIFIED/SLOWER ECMWF/UKMET SCENARIO. POTENTIAL FOR SIGNIFICANT
WINTER STORM REMAINS...WITH HIGHEST CHANCES FOR PRECIP COMING SAT
NIGHT THROUGH SUNDAY...AND POSSIBLY PERSISTING THROUGH MON IF
ECMWF IS TAKEN AS A PERFECT PROG.

BIGGEST CAVEAT TO KEEP IN MIND IS THAT DESPITE GROWING MODEL
CONSENSUS FOR UPR LVL PATTERN DURING THE LTR SAT-MON
TIMEFRAME...THE TIMING/TRACK OF THE SYSTEM REMAINS VERY MUCH
UNCERTAIN (LATEST ENSEMBLE SPREADS REMAIN SIGNIFICANTLY LARGE FOR
SFC LOW TRACK...A FACTOR WHICH CANNOT BE OVERSTATED). THE DEGREE
OF PHASING UPON REACHING THE COAST...AND (THUS) THE IMPACT ON THE
LLVL THERMAL STRUCTURE WILL BE CRITICAL. AS IT APPEARS NOW USING
THE AFOREMENTIONED GUIDANCE...PREDOMINANT WX TYPE EARLY SATURDAY
WOULD BE LGT RAIN OVER FAR SE VA/NE NC...LGT SNOW OVER MOST OF
CENTRAL VA WITH A NARROW STRIP OF MIXED PCPN (RASN) IN BETWEEN.
COLDER AIR WILL EVENTUALLY TAKE OVER FOR LATER SAT NGT/SUN MRNG
AND ALL AREAS...EVEN THE TIDEWATER/HAMPTON ROADS AREAS INTO NE
NC...WL HAVE A CHANCE FOR SIGNIFICANT SNOW ACCUMULATION AS THE SFC
LOW EXITS AND BOMBS OFF THE MID-ATL COAST DURING THE DAY SUNDAY.

BASED ON THE GFS/ECMWF LLVL THICKNESSES (WHICH ARE ALSO CLOSE)
AND LIKELIHOOD OF EXTENSIVE CLOUDS/PRECIP...HIGHS MAY NOT GET OUT
OF THE LWR-MID 30S BOTH SAT/SUN OVER THE NRN HALF OF THE FCST
REGION. MEANWHILE... LIKELY COLDER THAN MOS ON SUN WITH THE STRONG
CAA AND PSBL CONTINUED CLOUDINESS/WRAP AROUND PCPN BEHIND
DEEPENING OFFSHORE LOW (AND TEMPS MAY ACTUALLY FALL DURING THE DAY
SUNDAY ALONG THE COAST AS LOW LVL FLOW BACKS FROM NE TO N THEN
NNW LATER IN THE DAY).

STILL QUITE A BIT OF TIME LEFT TO GET A BETTER EVALUATION OF THIS
SYSTEM...ASSESSING COMPARABLE ANALOGS (CIPS ANALOG GUIDANCE LESS
VALUABLE IN THIS INSTANCE WITH GFS SOLN DISREGARDED FOR THIS
PACKAGE).GIVEN THE TIMING (LIKELY HAVING AN IMPACT DURING ONE OF THE
BUSIEST TRAVEL TIMES OF THE HOLIDAY SEASON)...WILL CONTINUE TO
OUTLOOK THE WINTER WX THREAT IN THE HWO.

[Stephanie]

I don't believe this!!!!

[cycloneye]

Afternoon discussion from NWS in Mount Holly,NJ.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
349 PM EST WED DEC 22 2010

.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL SWING THROUGH OUR REGION
TONIGHT. AN AREA OF HIGH PRESSURE EXTENDING FROM SOUTHERN CANADA
INTO THE PLAINS STATES WILL TRY TO BUILD EASTWARD FOR THURSDAY
THROUGH SATURDAY AS LOW PRESSURE MEANDERS NEAR THE CANADIAN
MARITIMES. OVER THE WEEKEND, LOW PRESSURE IS EXPECTED TO DEVELOP
OVER THE GULF COAST STATES AND PASS OFF THE SOUTHEASTERN SEABOARD ON
SUNDAY. THIS LOW PRESSURE WILL THEN INTENSIFY AS IT TRACKS
NORTHEASTWARD.--.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...

AS HAS BEEN THE CASE FOR THE PAST FEW DAYS...THE FOCUS OF THIS
FORECAST PERIOD WILL BE THE SUNDAY INTO MONDAY TIMEFRAME.

SATURDAY NIGHT SHOULD BEING DRY AND COLD AS HIGH PRESSURE OOZES
EAST FROM WESTERN ONTARIO AND THE UPPER MIDWEST...WHILE LOW PRESSURE
STARTS TO DEVELOP ACROSS THE EASTERN GULF STATES. AT THIS POINT...
BASED ON THE GUIDANCE HAS BEEN TRENDING...SATURDAY NIGHT LOOKS DRY.

THERE IS STILL ENOUGH MODEL SPREAD FOR UNCERTAINTY TO REMAIN THE
BIGGEST PART OF THE FORECAST FOR THE SUNDAY INTO MONDAY TIMEFRAME.
THE JET STREAK COMING ASHORE NOW IN SOUTHERN CALIFORNIA WILL MOVE
QUICKLY THROUGH THE SOUTHERN STREAM...REACHING TEXAS FRIDAY
AFTERNOON...THEN THE GULF STATES INTO SUNDAY MORNING. THE MAIN
FORECAST PROBLEM APPEARS TO BE WHETHER SIGNIFICANT PHASING WILL
OCCUR...AS A NORTHERN JET STREAK DIPS INTO THE LONG WAVE TROUGH
POSITION.

A FAIR AMOUNT OF MID RANGE GUIDANCE SUGGESTS THAT THIS WILL OCCUR...
BUT PROBABLY TOO LATE TO HAVE A MAJOR IMPACT ON THE FORECAST AREA.
THE 1200 UTC GFS AND GLOBAL GEM SUGGEST THIS SCENARIO...WITH SOME
POTENTIAL FOR SIGNIFICANT ACCUMULATING IN DELAWARE AND COASTAL NEW
JERSEY...BUT PROBABLY NOT ELSEWHERE. THIS SCENARIO WOULD POSE A
GREATER THREAT TO OUT NORTHEAST.

THE 1200 UTC ECMWF HAS BEEN KEEPING THE FAITH WITH REGARD TO A
SIGNIFICANT STORM FOR THE REGION SUNDAY INTO MONDAY. IT IS SLOWER
AND DEEPER IN THE MID LEVELS...AS RESULT OF EARLIER PHASING ACROSS
THE SOUTHERN UNITED STATES. THE GREATEST DEEPENING WOULD OCCUR JUST
OFF THE MID ATLANTIC COAST...WITH ALMOST ALL OF THE FORECAST AREA
RECEIVED A SIGNIFICANT WINTER STORM (COMPLETE WITH STRONG WINDS).

RIGHT NOW...BECAUSE WE ARE CONSIDERING AN IMPULSE NOW JUST GETTING
TO THE SOUTHERN CALIFORNIA COAST...IT IS STILL TOO EARLY TO SPEAK
WITH ANY DEGREE OF CONFIDENCE. HOWEVER...THERE DOES NOW APPEAR TO BE
ENOUGH CONSENSUS TO RAISE THE CHANCE OF SNOW...ESPECIALLY NEAR THE
COAST...FOR SUNDAY NIGHT INTO MONDAY. AS THE IMPULSE GETTING INTO
SOUTHERN CALIFORNIA MOVE EASTWARD...PERHAPS WE CAN NAIL DOWN SOME OF
THE SPECIFICS...BUT FOR NOW THERE STILL EXISTS THE POTENTIAL FOR A
WINTER STORM IN THE SUNDAY INTO MONDAY TIMEFRAME.

AFTER THE LOVE WAVE PATTERN MOVES TO THE EAST...THE FLOW IN THE LOW
TO MID LEVELS BECOMES NORTH TO NORTHWEST. OTHER THAN SOME SNOW
SHOWERS IN THE HIGHER TERRAIN...THIS SHOULD RESULT IN A DRY PATTERN
FOR TUESDAY AND WEDNESDAY...AS HIGH PRESSURE BUILDS EAST FROM THE
GULF STATES.

[cycloneye]

Afternoon discussion from the New York's NWS.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
305 PM EST WED DEC 22 2010

.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM SOUTH OF NEWFOUNDLAND WILL SLOWLY MOVE
NORTH AND EAST THIS WEEK. MEANWHILE HIGH PRESSURE OVER SOUTH CENTRAL
CANADA AND THE MIDWEST WILL SLOWLY BUILD EAST. LOW PRESSURE OVER
THE LOWER MISSISSIPPI VALLEY CHRISTMAS EVE IS FORECAST TO MOVE OFF
THE SOUTHEAST COAST CHRISTMAS NIGHT...THEN INTENSIFY AS IT TRACKS
NORTHEAST. THIS LOW IS FORECAST TO PASS NEAR THE AREA SUNDAY NIGHT AND
MONDAY.

&&

...LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
BIG QUESTION THIS TIME FRAME IS HOW QUICKLY UPPER LOW CLOSES OFF AND
AMPLIFIES...WHICH WILL HAVE A HUGE IMPACT AND SFC LOW TRACK AND
STRENGTH. WILL FOLLOW HPC GUIDANCE...WITH A SFC LOW TRACK BETWEEN
OPERATIONAL NEW AND PREVIOUS RUN OF THE ECMWF AND OP GFS. THIS TRACK
HAS SUPPORT FROM MANY ENSEMBLE MEMBERS.

BEST GUESS FOR THIS FORECAST IS A SLIGHTLY FASTER TRACK THAN OP
ECMWF...AND JUST TO THE SOUTHEAST OF THE BENCHMARK.

NEED TO EMPHASIZE THAT PLENTY OF UNCERTAINTY REMAINS...AND A SHIFT
EAST OR WEST WILL HAVE A HUGE IMPACT ON FORECAST...BUT TIMING IS
BECOMING MORE CERTAIN...WITH A DELAY INTO SUNDAY AND MONDAY.

SFC LOW INITIALLY SOUTH INTO THE GULF WILL MOVE NORTHEAST TOWARD A
POSITION OFF THE MID ATLC/SE COAST BY SUNDAY MORNING. THIS DEPENDS
ON AMPLIFICATION OF UPPER TROUGH/CLOSED LOW. POTENTIAL FOR EXPLOSIVE
DEVELOPMENT OF THE SFC LOW AS IT TRACKS SOUTHEAST OF THE AREA LATE
SUNDAY AND MONDAY. WILL CONTINUE TO LAYER POPS FROM HIGHEST S/SE TO
LOWEST N/NW. FWIW...GFS ENSEMBLE MEAN QPF 1/2 TO 3/4 OF AN INCH OF
QPF...HIGHEST EAST. NEW OP ECMWF QUITE WET.

FOR NOW WILL CAP POPS IN OUR CWA AT HIGH CHANCE/LOW LIKELY FOR NOW.
AS FOR TEMPS...COLD ENOUGH FOR ALL SNOW. WILL CONTINUE TO FOLLOW
BELOW NORMAL GUIDANCE FOR TEMPS.

BY TUESDAY...THE UPPER LOW AND ASSOCIATED SFC LOW TRAVERSE TO THE
EAST WITH DEEP NORTHWEST FLOW IN ITS WAKE. WILL END ANY PRECIP
CHANCES BY TUESDAY...AND DRY WEATHER CONTINUES INTO WEDNESDAY AS
RIDGING BUILDS FROM THE WEST.-- End Changed Discussion --