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Potential Storm 11/7-11/8

Snow_Miser

By Snow_Miser,
in New York City Metro

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rygar

rygar

Posted
Posted

Sure most have read it, but really detailed (and wonderful) long term discussion from Mt Holly

.LONG TERM /WEDNESDAY THROUGH MONDAY/...

DUE TO SURFACE LOW TRACK DIFFERENCES EARLY THIS MORNING...WE WILL BE

STANDING PAT ON THE HIGH WIND WATCH FOR WEDNESDAY AND WEDNESDAY

NIGHT. PERHAPS THE BIGGEST CHANGE TO THE FORECAST WILL BE EXPANDING

THE POTENTIAL FOR SNOW ACROSS PORTIONS OF CENTRAL AND NORTHERN NEW

JERSEY WEDNESDAY NIGHT.

MODELS ARE IN GENERAL AGREEMENT WITH MASS FIELDS FOR WEDNESDAY AND

WEDNESDAY NIGHT AS THE SHORT WAVE OVER SOUTHERN ALBERTA EARLY THIS

MORNING PHASES WITH THE CLOSING MID LEVEL SYSTEM OVER NORTHWEST

ALABAMA. THEY ARE SIMILAR WITH THE CLOSED MID LEVEL SYSTEM WEDNESDAY

INTO WEDNESDAY NIGHT. HOWEVER...THERE ARE ENOUGH DIFFERENCES IN THE

WIND AND PRECIPITATION FIELDS TO RESULT IN A LOWER THAN AVERAGE

FORECAST FOR WEDNESDAY INTO WEDNESDAY. BECAUSE OF THIS...THE HIGH

WIND WATCH WILL BE ALLOWED TO STAY IN PLACE WITH THE EARLY MORNING

FORECAST PACKAGE.

THE 0000 UTC MODEL SUITE IS...FOR THE MOST PART...FURTHER EAST WITH

THE SURFACE DEVELOPMENT AND THE STRONGEST WINDS FIELD (THE 0000 UTC

NAM IS THE EXCEPTION HERE). WITH THE CONSENSUS OF THE MODEL

SOLUTIONS NOW JUST A BIT FURTHER OFFSHORE...THE CORE OF THE

STRONGEST LOW LEVEL WINDS (UP THROUGH 925 MB) REMAINS JUST OFFSHORE

OVER THE COASTAL WATERS AND NORTHEAST OF THE AREA. THE CHANGE WOULD

IMPLY THAT THE STRONGEST WINDS WOULD REMAIN EAST OF THE AREA...WITH

THE HIGH WIND POTENTIAL A LITTLE LOWER (BASED ON THE 0000 UTC

OUTPUT).

MODEL SOUNDINGS FROM BOTH THE NAM AND GFS SHOWS THE LOWERED

POTENTIAL...AS THE DEPTH OF THE MIXED LAYER MAY NOT BE AS DEEP AS

EARLIER THOUGH. THIS WOULD BE PRIMARILY DUE TO THE COOLER AND

SHALLOWER BOUNDARY LAYER. HOWEVER...GIVEN THAT THE TRACK IS STILL

PROBABLY NOT SET...THERE IS STILL ENOUGH UNCERTAINTY TOP LET THE

HIGH WIND WATCH REMAIN IN PLACE.

DRY AIR IN PLACE SHOULD SLOW THE INTRODUCTION OF PRECIPITATION

WEDNESDAY MORNING AS THE SURFACE SYSTEM STARTS TO RESPOND TO THE

CLOSED MID LEVEL SYSTEM. AS THE MID LEVEL FRONTOGENETIC FORCING

ROTATES BACK TOWARD THE WEST AROUND THE MID LEVEL SYSTEM...BANDS OF

PRECIPITATION SHOULD MOVE WEST ACROSS THE FORECAST AREA. THE DRY AIR

IN PLACE SHOULD SLOW THE PROCESS...AND COULD EVEN STOP THE WESTWARD

PROGRESS IN THE LEHIGH VALLEY AND SOUTHERN POCONOS DURING THE MID TO

LATE AFTERNOON.

PRECIPITATION TYPE COULD END UP BEING MORE INTERESTING THAT PREVIOUS

FORECASTS. THE 0000 UTC UPPER AIR ANALYSIS SHOWS THE COLD AIR IN

ALREADY IN PLACE...AND DOES NOT REALLY MOVE OUT WITH THE APPROACH OF

THE MID LEVEL SYSTEM. THERE IS EVAPORATIVE COOLING IN PLACE DURING

THE EARLY PART OF THE PRECIPITATION...AND DYNAMIC COOLING BECOMES

IMPORTANT LATE WEDNESDAY AFTERNOON AND WEDNESDAY EVENING.

THE BOUNDARY LAYER MAY END UP BEING TOO WARM FOR SNOW TO ACCUMULATE

DURING THE DAY WEDNESDAY OUTSIDE OF THE HIGHER TERRAIN. DUE TO

EVAPORATIVE COOLING AND PRECIPITATION WEDNESDAY...HIGHS WERE

GENERALLY 2 TO 4 DEGREES BELOW THE MOS BLEND.

THE MAIN PRECIPITATION TYPE PROBLEM COULD OCCUR WEDNESDAY EVENING.

DURING THAT TIME...DYNAMIC COOLING WILL BE AT IT PEAK...WITH

LOWERING HEIGHTS RESULTING IN AN OVERALL COOLER COLUMN. MOST MODELS

SHOWS THE BEST MID LEVEL FRONTOGENETIC FORCING SETTING UP ACROSS NEW

JERSEY DURING THE EVENING. THIS IMPLIES THE BEST CHANCE OF

BANDING...AND THE BEST VERTICAL VELOCITY FIELDS. MODEL SOUNDINGS

SHOW THE BEST DENDRITIC GROWTH ZONES ACROSS NEW JERSEY DURING THE

EVENING AS WELL.

ALL OF THIS ADDS UP TO THE POTENTIAL FOR A PERIOD OF ACCUMULATING

SNOW ACROSS CENTRAL AND NORTHERN NEW JERSEY DURING WEDNESDAY

EVENING. THIS IS THE AREA WITH THE BEST OVERLAPPING MID LEVEL

FORCING AND DENDRITIC GROWTH. IF THIS WERE A MONTH LATER...THERE

WOULD BE POTENTIAL FOR ADVISORY LEVEL SNOWFALL. HOWEVER...THE

BOUNDARY LAYER TEMPERATURES AND GROUND TEMPERATURES MAKE FORECASTING

SNOWFALL AMOUNTS HERE PROBLEMATIC. RIGHT NOW...IT WOULD APPEAR

COLDER SURFACES WOULD HAVE A BETTER CHANCE TO SEE SOME

ACCUMULATIONS...WITH TRAVEL SURFACES TOO WARM FOR MUCH IN THE WAY OF

SNOWFALL ACCUMULATION.

FOR NOW...THERE IS POTENTIAL FOR ACCUMULATING SNOW IN THE

ABOVEMENTIONED AREA WEDNESDAY NIGHT...BUT THERE IS STILL

CONSIDERABLE UNCERTAINTY CONCERNING AMOUNTS. LOWS WERE MAINLY BASED

ON THE MOS BLEND...AND DROPPED A TAD DUE TO THE COOL COLUMN.

MOS MODELS SHOW THE BEST PRESSURE GRADIENT AND AND STRONGEST 925 MB

WIND BETWEEN 0000 UTC AND 0600 UTC. AS MENTIONED EARLIER...MODELS

ARE STARTING TO HINT THAT THE BEST LOW LEVEL WIND FIELD MAY STAY

JUST OFFSHORE...BUT THERE IS TOO MUCH UNCERTAINTY TO MAKE ANY

CHANGES TO THE HIGH WIND WATCH RIGHT NOW.

AS THE MID LEVEL SYSTEM TRUNDLES OFF TO THE NORTHEAST THURSDAY...THE

STEADIEST PRECIPITATION SHOULD END FROM SOUTHWEST TO NORTHEAST. THE

COLUMN MAY STILL BE COLD ENOUGH FOR MIXED PRECIPITATION THURSDAY

MORNING. HOWEVER...WITH THE LOSS OF SIGNIFICANT UPWARD LIFT WITH THE

MID LEVEL SYSTEM...THE PRECIPITATION TYPE PROBLEMS PROBABLY SHIFT TO

THE HIGHER TERRAIN. DRIER AIR WILL TRY TO GET INTO THE REGION DURING

THE AFTERNOON...AND THIS MAY FINALLY ALLOW THE SHOWERS TO END

GRADUALLY DURING THE MID TO LATE AFTERNOON ACROSS EASTERN AREAS.

THE COLUMN GRADUALLY WARMS DURING THURSDAY AFTERNOON...BUT CLOUDS

AND PRECIPITATION IN THE MORNING SUGGEST THAT THERE WOULD NOT BE

MUCH IN THE WAY OF TEMPERATURE RECOVERY IN THE AFTERNOON. WITH THIS

IN MIND...HIGHS WERE GENERALLY BASED ON THE COLDER NAM MOS NUMBERS.

THE BEST GRADIENT SHOULD OCCUR IN THE MORNING HOURS...WITH WIND

GUSTS NEAR ADVISORY LEVELS STILL POSSIBLE ACROSS EASTERN SECTION AS

WELL AS ACROSS THE HIGHER TERRAIN. THE GRADIENT SLOWLY BACKS OFF IN

THE AFTERNOON...BUT THIS MAY END UP BEING MITIGATED BY DEEPER MIXED

LAYERS. IN ANY EVENT...THURSDAY AFTERNOON STILL LOOKS WINDY...BUT

GUSTS SHOULD DROP BELOW ADVISORY LEVELS ACROSS ALL AREAS.

DRYING SHOULD RETURN THURSDAY NIGHT...AS MID LEVEL HEIGHTS START TO

RISE IN THE WAKE OF THE STORM. DRY CONDITIONS ARE EXPECTED FRIDAY

INTO THE WEEKEND AS MID LEVEL HEIGHTS CONTINUE TO RISE...AND SURFACE

HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY. THERE IS SOME

INDICATION THAT MOISTURE COULD TRY TO POOL ALONG A DEVELOPING

SURFACE WARM FRONT FOR SATURDAY NIGHT AND SUNDAY MORNING...BUT

LITTLE CHANGE WAS MADE TO THE PART OF THE FORECAST. 850 MB

TEMPERATURES OVER THE WEEKEND SUGGEST HIGHS WELL INTO THE 60S...

WHICH WOULD 10 DEGREES ABOVE NORMAL.

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PB GFI

PB GFI

Posted
Posted

40 degrees , cold rain , 40 mph wind gusts , 1 inch QPF for city and surrounding suburbs

I think its goin to be hard pressed to see any accumulating snow anywhere close to the city . surface temps are too warm

and without the system deepening rapidly , dynamic cooling not in the cards in my opinion for this one .

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