Tri-State area to be impacted by Major Winter Storm

[cycloneye]

AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE UPTON NY
443 PM EST THU JAN 20 2005

...MAJOR WINTER STORM TO IMPACT TRI-STATE AREA THIS WEEKEND...

.SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...AFTER SEVERAL DAYS OF
WATCHING MODEL TRENDS ON A POTENTIAL SNOWSTORM FROM THE MID ATLANTIC
STATES INTO SOUTHERN NEW ENGLAND...CONFIDENCE IS NOW HIGH FOR A
MAJOR SNOWFALL EVENT FOR THE TRI-STATE AREA. MUCH OF THE REGION BY
SUNDAY MORNING WILL BE BLANKETED BY A FOOT OR MORE OF SNOW.

THE ETA...ECMWF...UKMET...AND CANADIAN MODELS HAVE ALL TRENDED TO A
MAJOR OCEANIC LOW FORMING TO THE SOUTH AND EAST OF LONG ISLAND SAT
EVE. PRIOR TO THAT...LOW PRESSURE DROPS SOUTHEAST FROM THE UPPER
MIDWEST AND INTO THE OHIO VALLEY BY DAYBREAK SAT. AS THE SYSTEM
APPROACHES THE MID ATLANTIC STATES SAT EVE...THE UPPER FORCING
SHIFTS TO THE COAST AND A STRONG OFFSHORE BAROCLINIC ZONE. THE GFS
HAS BECOME THE LONE MAN OUT...WITH A WEAKER AND FARTHER SOUTH
SOLUTION BY 12Z SUN. IRONICALLY...THE BEST FRONTOGENETIC FORCING IS
PLACED TO NORTH OF THE CENTER...WHERE HEAVY SNOWS ARE LIKELY TO FALL
IN ADDITION TO THE COMMA HEAD REGION OF THE DEEPENING OCEANIC LOW.
PRIOR TO THE SECONDARY LOW TAKING SHAPE...STRONG WARM ADVECTION WILL
PRODUCE MODERATE TO HEAVY SNOWS SAT AFTERNOON.

ADDITIONALLY...JUST IN...THE 18Z MESO ETA HAS TRENDED EVEN FATHER
NORTH WITH THE SFC LOW AND PRODUCES OVER 2 INCHES OF QPF ACROSS LONG
ISLAND...NYC...AND SOUTHEAST CT. HOWEVER...SOME WARMING EVIDENT IN
THE LOW-LEVELS MAY RESULT IN A WINTRY MIX FOR A PERIOD AT THE COAST.
THIS WILL HAVE TO BE WATCHED WITH SUBSEQUENT RUNS. FOR NOW
THOUGH...WILL KEEP THIS AN ALL SNOW EVENT.

DETAILS...ARCTIC HIGH PRESSURE BUILDS ACROSS THE AREA OVERNIGHT WITH
CLEAR SKIES EARLY...THEN MID AND HIGH LEVEL CLOUDINESS MOVES IN
TOWARD DAYBREAK. SNOWS BREAK OUT IN THE LATE MORNING FROM WEST TO
EAST AND PICK UP IN INTENSITY DURING THE MID TO LATE AFTERNOON.
SNOWFALL RATES OF 2 TO 3 INCHES AN HOUR ARE POSSIBLE DURING THE
HEIGHT OF THE STORM...MAINLY BETWEEN 00Z AND 06Z. THE COMBINATION OF
THE RAPIDLY DEEPENING LOW AND THE POOL OF ARCTIC AIR ALREADY IN
PLACE...WILL ALLOW FOR STEEP LAPSE RATES AND A DEEP MIXED
LAYER...THUS ALLOWING STRONG WINDS ALOFT TO MIX DOWN TO THE
SURFACE. THE TIGHTEST PRESSURE GRADIENT WILL LIKELY BE OVER THE
COASTAL PLAINS...WHERE BLIZZARD CONDITIONS ARE LIKELY TO BE MET
DURING THE OVERNIGHT. THUS...A WINTER STORM WARNING HAS BEEN ISSUED
FOR THE INTERIOR WITH A BLIZZARD WARNING ALONG THE COAST.

THE SNOW TAPERS OFF SUN MORNING FROM WEST TO...BUT MIGHT LINGER INTO
THE EARLY AFTERNOON FOR EASTERN ZONES AS A DEFORMATION ZONE ON THE
BACKSIDE OF THE SYSTEM LINGERS BACK TO THE SOUTHWEST. SKIES BEGIN TO
CLEAR DURING THE LATE AFTERNOON/EARLY EVENING HOURS. CONSIDERABLE
BLOWING AND DRIFTING IS EXPECTED DURING THE DAY SUN BEFORE WINDS
DIMINISH IN THE EVENING.


For those who live in the Tri-State area here is the very latest discussion from the NWS about what to expect.

[donsutherland1]

Great discussion by OKX.