Jan 15-16 MidAtl/NE Winter Storm, Reality: Short Range (0-3 Days) Forecast Options

[Undertakerson]

WWA for most all of the interior of PA - good thing the timing is in evening as this looks nasty for road conditions.

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 PM THIS EVENING TO
11 AM EST WEDNESDAY...

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS ISSUED A WINTER
WEATHER ADVISORY FOR A WINTRY MIX OF PRECIPITATION...WHICH IS IN
EFFECT FROM 7 PM THIS EVENING TO 11 AM EST WEDNESDAY.

* LOCATIONS...MUCH OF CENTRAL PENNSYLVANIA ALONG AND SOUTH OF
INTERSTATE 80.

* HAZARD TYPES...A COATING OF FREEZING RAIN...SLEET AND SNOW.

* ACCUMULATIONS...A THIN GLAZE OF ICE FROM FREEZING RAIN...AS WELL
AS LIGHT TO MODERATE ACCUMULATIONS OF SNOW AND SLEET. THE
HEAVIEST SNOW WILL FALL OVER THE POCONOS...WHERE 2 TO 3 INCHES
OF SNOW SHOULD FALL. THE PRECIPITATION MAY TURN TO RAIN IN THE
VALLEYS.

* TIMING...THIS EVENING INTO EARLY WEDNESDAY MORNING.

* IMPACTS...SLOWED TRAVEL DUE TO MINOR ACCUMULATIONS OF ICE FROM
FREEZING RAIN AND A LIGHT ACCUMULATION OF SLEET AND SNOW

I mentioned yesterday that even my zone will be way close to the boundary zone - should be interesting Nowcast later on today. Noticing how CTP uses past events for analogy to potential precip types. Some in here have been using a similar analogy, and are thus supported by the "pros".

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
WAVE FROM THE LOWER MS VALLEY RUNS POLEWARD ALONG THE STATIONARY
BOUNDARY TO OUR SOUTH. ALL MODEL SOLUTIONS MATCH VERY WELL ON
TIMING...QPF AND AS WELL AS CAN BE EXPECTED ON PRECIP
TYPE/VERTICAL THERMAL PROFILES. ARRIVAL OF PRECIP IN THE S IS IN
THE EVENING...AND AROUND MIDNIGHT IN THE NERN COS. QPF OF 0.2 TO
0.4 IS EXPECTED WITH MUCH OF THE PRECIP NORTH OF ROUTE 22 FALLING
AS SNOW OR SLEET. THE SRN AND CENTRAL AREAS WILL BE WARM ENOUGH
ALOFT TO HAVE SOME FREEZING RAIN. BUT THE ACCUMULATIONS SHOULD BE
MINOR DUE TO RELATIVELY HIGH BUT STILL SUB-FREEZING TEMPS. AREAS N
OF I-80 AND IN THE HIGHER TERRAIN OF THE POCONOS WILL BE MOST
LIKELY TO APPROACH OR EXCEED 3 INCHES OF SNOW FOR THE EVENT. THE
PRECIP WILL MOST LIKELY STAY RAIN SE OF BLUE MTN...EXCEPT OVER THE
HIGHER TERRAIN OF WRN/NRN ADAMS CO. VALLEYS FARTHER TO THE N COULD
ALSO BE MAINLY RAIN OR HAVE JUST MINOR ACCUMS OF SLEET/SNOW. BUT
ENOUGH OF A THREAT FOR A GLAZE OF ICE FROM FZRA EXISTS OVER A
GREAT PORTION OF THE AREA TO WARRANT AN ADVY. THE PRECIP THUS FAR
IN THE WINTER HAS BEEN MORE-SNOWY THAN SLEET OR FZRA. THIS EVENT
MAY BE THE SAME WITH DRY AIR BELOW THE CLOUDS AT FIRST WHICH WILL
ALLOW FOR GOOD EVAP COOLING...AND THE PRECIP SHOULD BE MAINLY
OVERNIGHT. BUT THE WARM AIR ALOFT DOES MAKE IN-ROADS OVER THE SRN
HALF OF THE AREA TO CREATE A WINTRY MESS...ALBEIT A MINOR MESS.

DUE TO THE HIGH CONFIDENCE AND CONTINUOUS FORECAST OF A POSSIBLE
GLAZE OF ICE AND 2-3 INCHES OF SNOW IN THE EAST...WINTER WX ADVYS
HAVE BEEN POSTED.

AGAIN...THE TIMING FOR EXIT OF PRECIP IS VERY CONSISTENT. EXPECT
ONLY LIGHT SNOW OR DRIZZLE TO BE LEFT AFTER 8 OR 9 AM...AS THE
DEEPENING LOW MOVES OFF THE DELMARVA IN THE MORNING. WILL HOLD THE
ADVY FOR ALL AREA THROUGH THE MORNING...PADDING THE ENDING TIME
FOR SOME UNCERTAINTY ON HOW QUICKLY IT WILL TAPER OFF.

http://forecast.weather.gov/product.php?si...p;highlight=off

This post has been edited by Undertakerson: Jan 15 2013, 05:11 AM

[Undertakerson]

I could be wrong, but the SKEWT readings look like a small chance of rumbling during mid evening hrs.

http://www.twisterdata.com/index.php?sound...p;archive=false

I'll have to remember to keep a monitor on that situation. This could, quite literally, be an event where I can look from atop my perch and south and watch it rain beyond my front yard AND then turn in my seat to the north and watch is snow beyond my back yard.

This post has been edited by Undertakerson: Jan 15 2013, 05:26 AM

[Undertakerson]

starting to see the crit thickness lines move south and east. They previously bisected PA' northwest corner - now have moved to almost exactly bisect PA from its S/W corner to its N/E corners (extrapolate northward and southward from there, up towards ME and back towards KY)

Meso discussion for FZRA down southwest of here - may have to follow that trajectory throughout the day

http://www.spc.noaa.gov/products/md/md0034.html