After this week's warmth and rain, as expected, things start to cool down and our first chance at some light mix/snow is Thursday night into Friday, as this system now appears to be moving closer to us. Best guess now is some light rain changing to light snow late Thursday night, especially S and E of I-95, where an inch or two could fall (same in NYC and LI, i.e, more towards LI), although 3-4" is possible, as is nearly nothing - very borderline event with the amount of precip in question, as well as the type. It's most likely this will just be a nuisance event with borderline boundary layer (surface) temps at or above 32F, such that accumulations would likely be limited to colder surfaces, although at night it's always possible with enough intensity there could be small accumulations on paved surfaces. This system may completely miss places more than 20-30 miles NW of I-95.
Next threat is Monday into Tuesday, which is looking a bit more serious, although it's still 5+ days out, so not worth worrying about yet. But this has the potential to bring significant snow (6" or more) to most of the I-95 corridor from Philly to NYC (at least). This far out is also has the potential to mostly miss us out to sea or come further inland with more rain/mix for I-95/coast. Don't need to sound any alarms, but worth watching this one. For comparison sake, at the same point for the recent blizzard, there was much more indication of that being a huge snowstorm (although not necessarily for NYC) vs. this one. Great write-up by the NWS, below and also included a link to the AmericanWx site. And it looks to get colder after Tuesday...
FOR THURSDAY NIGHT AND FRIDAY...A FAIRLY NARROW UPPER-LEVEL
TROUGH
IS FORECAST TO SHARPEN UP SOME AS IT NEARS THE EAST COAST. THIS
ALLOWS FOR A SURFACE LOW TO DEVELOP ALONG THE OFFSHORE
FRONT, AND
OVERALL THE MODEL GUIDANCE IS FARTHER WEST WITH THE WESTERN EDGE OF
THE PRECIPITATION SHIELD. THERE APPEARS TO BE ENOUGH SHARPENING OF
THE
TROUGH TO ALLOW LIFT TO GET TO AT LEAST THE EASTERN ZONES FOR A
TIME DURING THURSDAY NIGHT AND FRIDAY MORNING, AND IF THE
TROUGH CAN
BECOME A BIT MORE NEGATIVELY TILTED THEN THE PRECIPITATION COULD BE
PULLED FARTHER WEST. THERE IS COOLING FORECAST TO TAKE PLACE AS THIS
IS OCCURRING AND WE ARE NOTING THE MODEL GUIDANCE LOWERING THE
SURFACE
DEW POINTS AS WELL /WEST TO EAST/. THIS COULD ALLOW FOR A
PERIOD OF RAIN TO MIX WITH AND EVEN CHANGE TO SNOW BEFORE ENDING.
THE FORECAST SOUNDINGS IN GENERAL SUPPORT MORE RAIN THAN SNOW AS THE
BOUNDARY LAYER MIGHT JUST BE TO MILD, HOWEVER IT MAY NOT TAKE MUCH
TO FLIP TO A PERIOD OF SNOW TOWARD THE COAST BEFORE IT ENDS WHICH
MAY ALLOW FOR AT LEAST SOME ACCUMULATION ON NON-PAVED SURFACES.
WE RAISED
POPS TO THE
LIKELY RANGE AND ALSO EXPANDED SOME
POPS
FARTHER INLAND, AND WE INCLUDED SOME LIGHT SNOW ACCUMULATIONS
OVERNIGHT AND EARLY FRIDAY MORNING. WE CONTINUED THE IDEA OF THE
RAIN MIXING WITH AND CHANGING TO WET SNOW BEFORE ENDING. SNOW
ACCUMULATIONS ARE LESS CERTAIN AS TEMPERATURES MAY REMAIN ABOVE
FREEZING DURING THE ENTIRE TIME PRECIPITATION IS FALLING. IT SHOULD
BE NOTED THAT THE WESTWARD EDGE OF THE MEASURABLE PRECIPITATION AND
ALSO PRECIPITATION TYPE/TRANSITION IS OF LOWER CONFIDENCE
ATTM,
HOWEVER GIVEN TRENDS IN THE MODEL GUIDANCE WE INCREASE
POPS,
QPF AND
INTRODUCED SOME SNOWFALL FOR THIS EVENT. THE SYSTEM THEN DEPARTS
FARTHER OFFSHORE DURING THE DAY FRIDAY WITH SOME CLEARING TAKING
PLACE FROM WEST TO EAST, THEN COLDER FRIDAY NIGHT.
FOR MONDAY AND TUESDAY...THE PATTERN MAY THEN TAKE ON SIGNIFICANT
AMPLIFICATION AS A ROBUST
TROUGH MOVES ACROSS THE PLAINS AND INTO
THE EAST DURING THIS TIME FRAME. THIS LOOKS TO RESULT IN LOW
PRESSURE INTO THE GREAT LAKES, HOWEVER THEN HANDING OFF ENERGY
EASTWARD THAT REDEVELOPS LOW PRESSURE OFF THE MID ATLANTIC COAST
LATE MONDAY AND TUESDAY. THE DEVELOPMENT/TRACK OF THIS STORM MAY
DEPEND ON THE ACTUAL TRACK AND INTENSITY OF THE PREVIOUS ONE. THERE
MAY ALSO BE HIGH PRESSURE ANCHORED JUST NORTH OF NEW ENGLAND. THIS
HAS THE POTENTIAL TO BECOME A DECENT COASTAL STORM WITH COLD AIR
COMING INTO PLAY. WHILE THERE IS A SIGNAL IN THE GUIDANCE REGARDING
THE STORM, THE TRACK AND INTENSITY IS LESS CERTAIN AND THAT WILL
DETERMINE THE ACTUAL DETAILS IF ANY FOR OUR AREA WHICH INCLUDES
RAIN, SNOW, WIND AND COASTAL IMPACTS.
FOR WEDNESDAY...A POTENTIALLY STRONG
TROUGH IS FORECAST TO BE IN THE
EAST, BASICALLY MOVING OVER OUR AREA. THIS WOULD TAKE ANY COASTAL
STORM OFF TO OUR NORTHEAST ALLOWING FOR IMPROVING CONDITIONS. AN
ARCTIC
FRONT MAY BE WAITING TO OUR NORTHWEST WEDNESDAY, HOWEVER
CYCLONIC
FLOW WILL RESULT IN SOME CLOUDS AND COLDER AIR WITH
POSSIBLY EVEN SOME SNOW SHOWERS.
http://forecast.weather.gov/product...&format=CI&version=1&glossary=1&highlight=off
http://www.americanwx.com/bb/index.php/forum/11-new-york-city-metro/