February 2013 Major KU Nor'easter/Blizzard

[srainhoutx]

Since this appears to be one of the potentially bigger Winter Weather events in many years and will affect the major Megalopolis of the NE I-95 Corridor for the Philadelphia/New York City/Boston areas, we will keep information and photos here as we did with Super Storm Sandy. The latest short range meso guidance is spitting out totals of nearly 3 feet of snow and winds nearing Hurricane force beginning tomorrow and continuing into the weekend. It should be noted that major societal impacts from such an event, should it actually happen could be rather far reaching affecting air travel across the Globe. There are indications of 3-4 inch per hour snow fall rates with thunder snow as the dynamics will be very conducive a potentially crippling blizzard across that Region.

[srainhoutx]

Very impressive 12Z Global operational (Euro/GFS/SREF/NAM/CMC) and GEFS totals now suggested for New York City and Boston. QPF amount suggest 3+ inches liquid equivalent may well be possible which would conservatively add up to measurements in the feet of snow fall across the NE.

[MontgomeryCoWx]

Lordy, I'd love to fly up there today and experience this.

[srainhoutx]

Blizzard Warnings now hoisted for Newark, NJ/New York City and all of Long Island/All of CT/RI/Eastern Massachusetts and Coastal Maine/NH. Hurricane Force Wind Warning hoisted for Coastal waters off the NE Coast as well.

SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
348 PM EST THU FEB 07 2013

VALID 00Z FRI FEB 08 2013 - 00Z SUN FEB 10 2013

...MAJOR WINTER STORM EXPECTED FROM THE GREAT LAKES INTO THE
NORTHEASTERN U.S. WITH BLIZZARD CONDITIONS POSSIBLE FOR PORTIONS
OF NEW ENGLAND...

...NEAR OR ABOVE AVERAGE TEMPERATURES WILL PERSIST THROUGH THE
SHORT RANGE ACROSS THE CENTRAL U.S...

A COMPLEX WEATHER SCENARIO WILL UNFOLD ACROSS THE EASTERN HALF OF
THE NATION OVER THE NEXT 24 HOURS...IN WHICH TWO WEATHER SYSTEMS
FROM THE POLAR AND SUBTROPICAL JET STREAMS WILL COMBINE TO PRODUCE
A MAJOR AND POTENTIALLY HISTORIC WINTER STORM FOR THE NORTHEASTERN
U.S. THE NORTHERN STREAM SYSTEM IS MOVING THROUGH THE MIDWEST THIS
AFTERNOON...BRINGING RAIN TO THE MISSISSIPPI AND OHIO RIVER
VALLEYS...AND SNOW TO THE GREAT LAKES. THE SOUTHERN STREAM LOW
PRESSURE SYSTEM IS MOVING ACROSS THE GULF COAST THIS
AFTERNOON...AND SPREADING LOCALLY HEAVY RAIN ACROSS THE
SOUTHEASTERN STATES. THE GULF COAST SURFACE LOW WILL MOVE
NORTHEASTWARD TO NEAR CAPE HATTERAS BY EARLY FRIDAY MORNING AS IT
BEGINS TO INTERACT WITH THE SYSTEM OVER THE GREAT LAKES. THIS
INTERACTION WILL RESULT IN A RAPID STRENGTHENING OF THE COASTAL
SURFACE LOW DURING THE DAY ON FRIDAY AND INTO FRIDAY NIGHT AS THE
STORM CONTINUES TO MOVE UP THE COAST. THE STORM SHOULD REACH ITS
PEAK INTENSITY EARLY SATURDAY MORNING JUST EAST OF CAPE COD...WITH
A CENTRAL PRESSURE FORECAST TO DROP BELOW 975 MB. SNOW WILL BEGIN
TO SPREAD FROM THE GREAT LAKES INTO THE NORTHEASTERN STATES
TONIGHT AND WILL QUICKLY EXPAND ACROSS MOST OF THE NORTHEAST BY
FRIDAY AFTERNOON AS THE TWO SYSTEMS APPROACH. MODERATE TO HEAVY
SNOW WILL BE WIDESPREAD...AND STRONG WINDS OF 25 TO 35 MPH...WITH
GUSTS AS HIGH AS 75 MPH ARE POSSIBLE...RESULTING IN DANGEROUS
BLIZZARD CONDITIONS FOR SOUTHEASTERN NEW ENGLAND. IN
GENERAL...SNOWFALL TOTALS OF 1 TO 2 FEET ARE EXPECTED FROM THE
EASTERN GREAT LAKES INTO THE NORTHEAST. LOCALLY HIGHER SNOWFALL
AMOUNTS ARE POSSIBLE...WITH THE HEAVIEST SNOW FORECAST TO FALL
ACROSS AREAS OF SOUTHEASTERN NEW ENGLAND. FOR MORE DETAILS
SPECIFIC TO YOUR AREA...PLEASE REFER TO PRODUCTS ISSUED BY YOUR
LOCAL NWS FORECAST OFFICE.

ELSEWHERE...A PACIFIC STORM SYSTEM CURRENTLY ACROSS THE WESTERN
U.S. WILL MOVE EASTWARD RATHER SLOWLY THROUGH THE SHORT RANGE
FORECAST PERIOD. SCATTERED RAIN AND SNOW SHOWERS WILL OCCUR ACROSS
THE INTERMOUNTAIN WEST THROUGH SATURDAY AS THIS SYSTEM CROSSES THE
REGION. AHEAD OF THE SYSTEM...A RELATIVELY WARM AIR MASS WILL BE
IN PLACE ACROSS THE CENTRAL U.S....KEEPING TEMPERATURES NEAR OR
SLIGHTLY ABOVE AVERAGE ACROSS THIS REGION ON FRIDAY AND SATURDAY.

RYAN

[srainhoutx]

MESOSCALE DISCUSSION 0123
NWS STORM PREDICTION CENTER NORMAN OK
1150 AM CST FRI FEB 08 2013

AREAS AFFECTED...NRN NJ...SERN NY THROUGH SRN NEW ENGLAND

CONCERNING...HEAVY SNOW

VALID 081750Z - 082145Z

SUMMARY...SNOW WILL CONTINUE TO EXPAND NWD FROM NRN NJ AND SERN NY
THROUGH SRN NEW ENGLAND. SNOWFALL INTENSITY WILL GRADUALLY INCREASE
THROUGH THE DAY WITH RATES APPROACHING 1 INCH PER HOUR BY LATE
AFTERNOON OR EARLY EVENING. HEAVIEST RATES /2+ INCH PER HOUR/ ARE
EXPECTED TO EVOLVE DURING THE EVENING.

DISCUSSION...EARLY THIS AFTERNOON A DEEP SURFACE LOW WAS LOCATED
JUST OFF THE MID ATLANTIC COAST WITH A WARM FRONT EXTENDING EWD FROM
THE LOW INTO THE WESTERN ATLANTIC. THIS AREA OF LOW PRESSURE HAS
DEVELOPED IN ASSOCIATION WITH A VORT MAX NEAR THE CNTRL VA COAST AND
WITHIN A COUPLED UPPER JET STRUCTURE. AN EXPANSIVE AREA OF
PRECIPITATION IS IN PROGRESS FROM NJ INTO SRN NEW ENGLAND WITHIN
ZONE OF ISENTROPIC ASCENT NORTH OF WARM FRONT. SNOW RATES WITHIN
THIS AREA SHOULD GENERALLY REMAIN AOB 0.5 INCH PER HOUR THROUGH MID
AFTERNOON. PRECIPITATION MOSTLY IN THE FORM OF RAIN OVER LONG ISLAND
SHOULD TRANSITION TO SNOW DURING THE EVENING AS THE WARM NOSE AOB
850 MB BEGINS TO COOL WITH THE ONSET OF COLD ADVECTION NW OF THE LOW
CENTER.

LATEST OBJECTIVE ANALYSIS INDICATES A ZONE OF STRONG 850-700 MB
FRONTOGENETIC FORCING WITHIN DEFORMATION AXIS JUST NE OF THE LOW
CENTER OFF THE SRN NJ COAST. THIS ZONE OF STRONG FORCING AND MID
LEVEL ASCENT WILL DEVELOP NWD THROUGH TODAY AS THE LEAD IMPULSE
INTERACTS WITH UPSTREAM TROUGH OVER THE GREAT LAKES AND EJECTS
TOWARD SRN NEW ENGLAND. THEREFORE...SNOWFALL RATES WILL UNDERGO A
SUBSTANTIAL INCREASE FROM NRN NJ INTO SRN NEW ENGLAND BY EARLY
EVENING AS ZONE OF ASCENT DEVELOPS NWD AND DEEPENS THROUGH THE
DENDRITIC GROWTH LAYER. THE SNOW SHOULD EVENTUALLY DEVELOP BANDED
STRUCTURES THIS EVENING WITHIN THE NWD DEVELOPING FRONTOGENETIC
ZONE...AND THERE IS ALSO SOME INDICATION THAT THERE COULD BE SOME
SLANTWISE CONVECTIVE ENHANCEMENT WITHIN THE BANDS.

..DIAL.. 02/08/2013


ATTN...WFO...BOX...OKX...ALY...PHI...

[srainhoutx]

MESOSCALE DISCUSSION 0124
NWS STORM PREDICTION CENTER NORMAN OK
0351 PM CST FRI FEB 08 2013

AREAS AFFECTED...SRN NEW ENGLAND...LONG ISLAND AND SRN NY...FAR NERN
NJ

CONCERNING...HEAVY SNOW

VALID 082151Z - 090145Z

SUMMARY...SNOWFALL RATES ARE EXPECTED TO INCREASE MARKEDLY THIS
EVENING ...WITH RATES OF 1-2 INCHES PER HR OVER SRN NY/NERN NJ...TO
2-3 INCHES ACROSS SRN NEW ENGLAND. ADDITIONALLY...STRENGTHENING
WINDS MAY RESULT IN LOCALIZED BLIZZARD CONDITIONS...ESPECIALLY NEAR
THE COAST.

DISCUSSION...SFC OBS FROM 21Z CONTINUE TO REFLECT A RAPIDLY
DEEPENING OFFSHORE CYCLONE...WITH PRESSURE FALLS OF 3-4 MB/HR
OBSERVED. RADAR REFLECTIVITY MOSAIC SHOWS HIGHER PRECIPITATION RATES
ARE BEGINNING TO SPREAD INLAND ACROSS LONG ISLAND AND TOWARDS RI/SRN
MA/SRN CT. HOWEVER...SOME BRIGHT-BAND ENHANCEMENT MAY BE OCCURRING
AS MIXED P-TYPE OF RAIN AND/OR SNOW IS PREDOMINANT ACROSS LONG
ISLAND...WHERE SFC TEMPERATURES ARE CURRENTLY RANGING FROM 33-35 F.
INITIALLY...NEAR- OR ABOVE-FREEZING TEMPERATURES MAY SUPPRESS RATES
IMMEDIATELY ALONG THE COAST...BUT WITH LOW-LEVEL COLD ADVECTION
INCREASING AS THE CYCLONE TRACKS N-NE...A CHANGEOVER TO
PREDOMINANTLY SNOW IS EXPECTED WITHIN THE NEXT 2-3 HRS ACROSS MOST
OF THE HIGHLIGHTED AREA.

SNOWFALL RATES WILL BE INCREASING IN CONCERT WITH INTENSE ISENTROPIC
LIFT AND LOW-LEVEL FRONTOGENESIS WITHIN A DEFORMATION ZONE.
ADDITIONALLY...AN UPSTREAM SHORTWAVE UPPER TROUGH /LOCATED OVER THE
UPPER OH VALLEY PER 2130Z WATER VAPOR IMAGERY/ IS FORECAST TO PHASE
WITH THE OFFSHORE DEEP-LAYER CYCLONE. AS THIS OCCURS...THE
COMBINATION OF STRONG MIDLEVEL HEIGHT FALLS AND UPPER DIVERGENCE
WITHIN A COUPLED UPPER JET STRUCTURE WILL CONTRIBUTE TO INCREASING
DEEP-LAYER ASCENT. FORECAST MODEL SOUNDINGS SHOW A NEARLY SATURATED
COLUMN WITH A DEEP ISOTHERMAL LAYER LOCATED BENEATH THE DENDRITIC
GROWTH ZONE. THESE FACTORS WILL BE FAVORABLE FOR EXTREMELY HIGH
SNOWFALL RATES...ESPECIALLY FROM ERN LONG ISLAND INTO SRN NEW
ENGLAND...INCLUDING THE BOSTON METRO AREA...AS SUPPORTED BY THE
RECENT SUITE OF HIGH-RESOLUTION NUMERICAL GUIDANCE.

..ROGERS.. 02/08/2013


ATTN...WFO...GYX...BOX...OKX...ALY...PHI...