Feb 26-28 MidAtl/NE Winter Storm, Possibility: Medium Range (4-7 Days Out) Forecasts Options

[Mike W IN herkim...]

local met

All of the latest data coming into the Weather Center continues to point to a mixed precipitation event for late Tuesday Night and Wednesday. This evening on the weather map a storm system is situated over the state of Arkansas. This storm is rather intense with a central pressure of 993 mbar. The low pressure center is expected to track into Indiana by late Tuesday afternoon and evening. Typically when a storm system tracks to our west it means a mixed bag of precipitation turns to rain for our area. That still is likely to be the case but it’s not as clear cut of a situation as usual.

During the day Tuesday the storm system will still be hundreds of miles away. The good news for commuters is that both the ride to work and the ride home from work should be free of any weather related travel problems. In fact, temperatures all across the northeast are at worst seasonably cold. With clouds and peeks of sun, afternoon mercury readings will climb well into the 30’s, perhaps even into the lower 40’s, in some areas.

As the storm system moves into the Upper Midwest we’ll see some precipitation break out over CNY. One thing to keep in mind is that as this precipitation breaks out, it’s going to be falling into an air mass that will likely have had temperatures climb several degrees above freezing for a time Tuesday afternoon. Indeed, the latest model output statistics (MOS) from the NAM model suggest it may take some time for the mercury to fall back to the freezing mark in the lower elevations.

How about precipitation type? This is been the toughest call in tracking this event over the past couple of days. The aforementioned low, by itself, would imply a mix to rain situation for CNY. But model consensus has shown a secondary storm system developing over the Mason-Dixon line as precipitation begins to break out locally. This secondary area of low pressure is likely to employ a “holding pattern” with any existing cold air, keeping temperatures locally lower than they would otherwise be without the second low. There’s also a chance that as this low develops, the pressure falls could lead to a process called “dynamic cooling” – where the air cools due to the expansion process created by the lower pressure. Temperatures aloft are expected to hover precariously close to the zero degree (Celsius) mark in the forecast temperature profiles. What that translates to is a probable mixed bag of precipitation types. We could see some bursts of snow during times of heavier precipitation, where the column of air cools completely below freezing from cloud base to ground. There’s also the good chance that at any time, somewhere between cloud and ground some layer of above freezing air could make for some freezing rain and sleet. This is especially likely during times of relatively lighter precipitation intensity. The bottom line is that from the time precipitation starts late Tuesday evening, right on through daybreak Wednesday, all forms of wintry precipitation, including snow, sleet, freezing rain are on the table.

On Wednesday, particularly once the precipitation begins to lighten up by afternoon, enough solar radiation is likely to find its way to ground level in this environment to allow temperatures to climb above freezing, particularly in valley locations. Patchy light rain and drizzle and some high elevation wet snow showers and flurries appear likely at this point.

http://www.wktv.com/weather/blogs

[NYCSuburbs]

I'm starting to wonder if this one also fails to break the T-2" event stretch... my main concerns are the warm nose at 850mb with precip type changing over faster in the Hudson Valley, along with how much precip makes it here while it's still cold enough for snow. For now I'd go with 2-4" but wouldn't surprise me to see it bust on the low side, like all but 3 or 4 storms this winter did.

[Mike W IN herkim...]

60 hrs worth of precip on the ggem

Total precip


total snow

[Weatherwatcher00...]

Is the Euro any colder for CT? Hoping more for a bit more than a few snowflakes here lol.

[Mike W IN herkim...]

Sounds like euro is warmer and less precip..Another storm bites the dust in the short range

[NYCSuburbs]

Sounds like euro is warmer and less precip..Another storm bites the dust in the short range

Wundermaps show the same observation, drier and warmer... secondary low is also a bit weaker with a slightly stronger primary. The primary is further west and holds on longer.

[Mike W IN herkim...]

kalb snowmap

[Mike W IN herkim...]

KALB

AS OF 430 AM...WE HAVE ISSUED A WINTER STORM WATCH TONIGHT THROUGH
EARLY THURSDAY MORNING FOR OUR EASTERN CATSKILLS...SOUTHERN GREENS
AND BERKSHIRES.

OVERALL MODEL GUIDANCE HAS TRENDED A SHADE COLDER...AT LEAST THROUGH
THE COLUMN. THE EUROPEAN MODEL STILL WAS THE COLDEST BUT EVEN IF WE
BLEND THEM...THERE IS CONCERN THAT SIGNIFICANT SNOW COULD ACCUMULATE
IN THE WATCH AREAS. ALSO...AN ANOMALOUSLY STRONG ESE WIND...REACHING
UP TO 65KTS AT THE H850 LEVEL...AND 40TS AT THE H925...COULD PRODUCE
ENHANCEMENT OF PRECIPITATION AS WELL AS RATHER STRONG GUSTY WINDS.
THE COMBINATION OF THE WIND...SNOW...MIXED WITH SLEET AND PERHAPS A
LITTLE FREEZING RAIN...COULD LEAD TO SCATTERED POWER OUTAGES IN
THESE AREAS.

LOW PRESSURE OVER NORTHERN ARKANSAS HAS ALREADY PRODUCED A LEGACY OF
WINTER WEATHER ACROSS PORTIONS OF THE PLAIN...THE SECOND BLIZZARD IN
ABOUT A WEEK!

THIS LOW WILL TRACK INTO THE OHIO VALLEY TODAY. AS IT ENCOUNTERS
SOMEWHAT COLDER AIR AND STRONG HIGH PRESSURE TO THE NORTHEAST...IT
WILL "SPLIT" INTO TWO PIECES OF ENERGY...ONE WHICH WILL SLOWLY
MEANDER INTO NEW YORK STATE BY THURSDAY. HOWEVER...A SECONDARY LOW
PRESSURE WILL FORM ACROSS INTERIOR VA BY THIS EVENING...THEN TRACK
ALONG OR JUST EAST OF THE I-95 CORRIDOR TONIGHT THROUGH WEDNESDAY.

THIS SECONDARY PIECE OF ENERGY WILL BRING THE FIRST ROUND OF
PRECIPITATION TO THE REGION BEGINNING LATER THIS EVENING. A STRONG
LOW LEVEL JET WILL BRING AN EXCEPTIONALLY STRONG U COMPONENT UP TO 5
STANDARD DEVIATIONS ABOVE NORMAL LATE TONIGHT THROUGH WEDNESDAY.
THIS WILL DRAW PWAT VALUES OF NEARLY AN INCH (TWO STANDARDS ABOVE
NORMAL) TOWARD OUR SOUTHEASTERN ZONES.

STRONG UPWARD MOTION LOOKS TO KEEP THE COLUMN COLD ENOUGH FOR MOSTLY
SNOW ACROSS AT LEAST THE HIGHER ELEVATIONS OF THE
CATSKILLS...SOUTHERN GREENS AND BERKSHIRES. THE DEEP MOISTURE DOES
NOT LOOK TO MAKE IT INTO THE ADIRONDACKS SO WHILE IT WILL BE
SLIGHTLY COLDER THERE...SNOWFALL DOES NOT LOOK TO BE ENOUGH TO
JUSTIFY A WATCH.

NORTH/SOUTH VALLEYS LOOK TO HAVE SOME SORT OF SHADOWING...AS THE ESE
WIND WILL RESULT IN SOME DOWNSLOPING OVERNIGHT INTO WEDNESDAY
MORNING...ALTHOUGH THE FLOW DOES NOT LOOK PERFECTLY ORTHOGONAL TO
THE HIGHER TERRAIN. HOWEVER...WE BELIEVE THERE WILL SOME
MINIMIZATION OF THE QPF IN THESE AREAS. ALSO...THIS DOWNSLOPING
WOULD SERVE TO WARM THE LOWEST LEVELS OF THE COLUMN (NAMELY THE
SURFACE) A BIT.

FOR THESE REASONS...WE DO NOT EXPECT A LOT OF SNOW IN THE VALLEYS
DESPITE THE FACT THE SOUNDINGS INDICATE MOSTLY SNOW COULD FALL EVEN
IN PLACES NORTH OF KINGSTON.

HOWEVER...THE TIMING OF THE SNOW...POTENTIALLY HEAVIEST AS WE HEAD
TOWARD THE MORNING DRIVE ON WEDNESDAY...COULD NEVERTHELESS IMPACT
TRAVEL AT THIS TIME. FOR NOW...NO ADVISORIES WILL BE ISSUED BUT
SOMETHING TO MONITOR.

LATER WEDNESDAY...AS SECONDARY LOW MOVES TO OUR EAST...THERE LOOKS
TO BE A TIME WHERE DRIER AIR INTRUDES THE MID LEVELS OF THE
ATMOSPHERE. THIS DRYING WILL LIKELY NOT BE ENOUGH FOR ANY
CLEARING...BUT MOST IF NOT ALL OF THE CLOUDS COULD LOOSE THEIR ICE
BY AFTERNOON...REDUCING PRECIPITATION TO LIGHT RAIN...DRIZZLE OR IN
THE CASE OF THE MOUNTAINS...A LIGHT WINTRY MIX.

TEMPERATURES ON WEDNESDAY WILL START OUT FROM THE MID 20S HIGHER
TERRAIN TO LOWER 30S MOST OF THE VALLEY LOCATIONS ON WEDNESDAY. THEY
SHOULD SLOWLY RISE TO NEAR 40 IN THE VALLEYS...LOWER TO PERHAPS MID
30S HIGHER TERRAIN.

THEN...BY WEDNESDAY EVENING...AS WHAT IS LEFT OF THE PLAINS
STORM...MAINLY AN UPPER LEVEL FEATURE...WILL NEVERTHELESS INTERACT
WITH SLOWLY DEEPENING LOW PRESSURE PUSHING NEAR CAPE COD AT THIS
POINT EVENTUALLY FORCING IT TO BECOME STACKED. THIS WILL PRODUCE
SOME SORT OF DEFORMATION PRECIPITATION...LIKELY ENHANCED DUE TO
UPSLOPE AGAINST HIGHER TERRAIN. FOR THIS REASON...WE EXTENDED THE
WINTER STORM WATCH AS ANOTHER ROUND OF SEVERAL INCHES OF SNOW COULD
ACCUMULATE ACROSS THE CATSKILLS/SOUTHERN GREENS AND BERKSHIRES. AN
INCH OR TWO COULD CERTAINLY ACCUMULATE IN VALLEY LOCATIONS AS WELL.
TEMPERATURES WEDNESDAY NIGHT LOOK TO BOTTOM OUT AT OR A BIT BELOW
FREEZING.

RIGHT NOW...THE POTENTIAL IS THERE FOR AT LEAST 6-12 INCHES OF SNOW
ACROSS THE WATCH AREA....MIXED WITH A SOME SLEET AND FREEZING RAIN.
AT THIS TIME...THERMAL PROFILES DID NOT INDICATE AN EXTENDED PERIOD
OF FREEZING RAIN...ALTHOUGH IT IS STILL REMOTELY POSSIBLE. THE SNOW
LOOKS TO BE OF THE WET VARIETY...PROBABLY NOT MUCH DRIFTING BUT IT
WILL BE HEAVY. FACTOR THAT WITH PROJECTED WIND GUSTS APPROACHING 40
MPH AT TIMES...COULD BRING SOME TREES AND WIRES DOWN...PERHAPS
LEADING TO SCATTERED POWER OUTAGES.

WIND WILL BE A CONCERN ACROSS ALL OF THE HIGHER TERRAIN...INCLUDING
THE ADIRONDACKS. HOWEVER...RIGHT NOW WE BELIEVE WIND GUSTS SHOULD
FALL SHORT OF WARNING CRITERIA (58 MPH)...PERHAPS REACHING WIND
ADVISORY THRESHOLDS OF GUSTS TO BETWEEN 40 AND 50 MPH. SINCE THAT IS
THE CASE...WE DECIDED TO HOLD OFF ONE MORE PERIOD TO SEE IF
ADVISORIES WILL REALLY BE NEEDED. WILL CONTINUE TO MENTION THIS
POSSIBILITY IN OUR HAZARDOUS WEATHER OUTLOOK.

IN THE VALLEYS AS WELL AS THE ADIRONDACKS...SNOWFALL LOOKS TO RANGE
FROM 2 TO 6 INCHES...HIGHEST NORTH OF ALBANY. THESE VALUES COULD
REACH ADVISORY THRESHOLDS IN SOME CASES...BUT AGAIN...DECIDED NOT
TO HEADLINE ANY ADVISORIES YET.

THURSDAY WE WILL STILL BE DEALING WITH LEFTOVER LIGHTER
PRECIPITATION IN THE FORM OF SNOW CHANGING TO RAIN SHOWERS IN THE
VALLEYS...OR MAINLY MOUNTAIN SNOW AS THE LARGE STACKED STORM SLOWLY
DRIFTS TO THE GULF OF MAINE. AT THIS POINT...ADDITIONAL
PRECIPITATIONS AMOUNTS LOOK FAIRLY LIGHT ON THURSDAY...WITH PERHAPS
ONE
EXCEPTION...SOUTHERN VERMONT WHERE SNOWFALL COULD BECOME MORE
ENHANCED. HIGH TEMPERATURES LOOK TO REACH 40-45 IN THE HUDSON
VALLEY...WHILE HOLDING IN THE LOWER TO UPPER 30S ACROSS THE HIGHER
TERRAIN.

http://forecast.weather.gov/product.php?si...mp;highlight=on

[PA ROAD DAWG]

kalb snowmap

Wow. Theyre really going gun ho on this one

[JDClapper]

According to the 21z SREF's..
http://www.spc.noaa.gov/exper/sref/fplumes...mp;mTYP=roadmap

<1" = 1 of 23 (5% chance)
1-3" = 7 of 23 (30% chance)
3-6" = 9 of 23 (39% chance)
>6" = 6 of 23 (26% chance)

Compare to the 15z SREF's..
<1" = 1 of 23 (5% chance)
1-3" = 10 of 23 (43% chance)
3-6" = 9 of 23 (39% chance)
>6" = 3 of 23 (13% chance)

Ever so slightly "colder"... but pretty much unchanged...

3z SREFs for IPT.. noticeably "warmer"
<1" = 5 of 23 (22% chance)
1-3" = 12 of 23 (52% chance)
3-5" = 6 of 23 (26% chance)

[NorEaster07]

kalb snowmap

Bit shocking to wake up to seeing half foot+ for litchfield... then again, Norfolk is called the ice box of CT and their average snowfall is over 4 feet a year so not surprising to see them get that much snow from this.

I'll get an OBS going in a bit..Putting some stuff together now

[JDClapper]

CPA snowmap.. NWS

[NorEaster07]

OBS Thread: http://forums.accuweather.com/index.php?showtopic=30651

[telejunkie]

WWWatch hoisted by KALY:
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE ALBANY NY
346 AM EST TUE FEB 26 2013


MAZ001-025-NYZ047-051-058-063-VTZ013-014-262200-
/O.NEW.KALY.WS.A.0002.130227T0400Z-130228T1100Z/
NORTHERN BERKSHIRE-SOUTHERN BERKSHIRE-SCHOHARIE-WESTERN ALBANY-
WESTERN GREENE-WESTERN ULSTER-BENNINGTON-WESTERN WINDHAM-
INCLUDING THE CITIES OF...PITTSFIELD...NORTH ADAMS...
GREAT BARRINGTON...LEE...LENOX...HOUSATONIC...COBLESKILL
..
MIDDLEBURGH...ALTAMONT...HUNTER...TANNERSVILLE...W
NDHAM...
SUNDOWN...ELLENVILLE...WOODSTOCK...WEST HURLEY...KERHONKSON...
NAPANOCH...PHOENICIA...BENNINGTON...JACKSONVILLE..
NEWFANE
346 AM EST TUE FEB 26 2013

...WINTER STORM WATCH IN EFFECT FROM THIS EVENING THROUGH LATE
WEDNESDAY NIGHT...

THE NATIONAL WEATHER SERVICE IN ALBANY HAS ISSUED A WINTER STORM
WATCH...WHICH IS IN EFFECT FROM THIS EVENING THROUGH LATE
WEDNESDAY NIGHT FOR THE EASTERN CATSKILLS...SOUTHERN GREENS AND
BERKSHIRES.


* HAZARD TYPES...SNOW...POSSIBLY HEAVY AT TIMES...MIXED WITH SLEET
AND SOME FREEZING RAIN.

* ACCUMULATIONS...POTENTIAL SNOW ACCUMULATIONS OF 6 TO 12 INCHES.


* ICE ACCUMULATIONS...A MINOR COATING OF ICE UP TO A TENTH OF AN
INCH POSSIBLE.


* MAXIMUM SNOWFALL RATES...AN INCH PER HOUR...MAINLY LATE TONIGHT
THROUGH WEDNESDAY MORNING.

* TIMING...SNOW...OR A WINTRY MIX ARRIVES AROUND MIDNIGHT. SNOW
HEAVY AT TIMES...MIXED WITH SLEET AND PERHAPS SOME FREEZING RAIN
THROUGH WEDNESDAY MORNING...BECOMING A LIGHT WINTRY MIX DURING
THE AFTERNOON. PRECIPITATION LIKELY CHANGING BACK TO ALL SNOW
WEDNESDAY NIGHT WITH ADDITIONAL SNOWFALL ACCUMULATIONS POSSIBLE.

* IMPACTS...THE POTENTIAL FOR TREACHEROUS TRAVEL LATER TONIGHT
THROUGH WEDNESDAY NIGHT.

* WINDS...EAST 15 TO 25 MPH WITH OCCASIONAL GUSTS UP TO 40 MPH.
THE COMBINATION OF WIND AND SNOW COULD CAUSE VERY LOW
VISIBILITIES UNDER A QUARTER OF A MILE. THE SNOW WILL LIKELY BE
HEAVY AND WET AND COMBINED WITH THE WIND COULD PRODUCE SCATTERED
POWER OUTAGES.

* TEMPERATURES...MID 20S TO LOWER 30S.

Slopfest 2013

This post has been edited by telejunkie: Feb 26 2013, 07:37 AM