A large winter storm brought periods of snow, sleet and freezing rain to central Pennsylvania. The initial round of mixed wintry precipitation (mainly snow and sleet) occurred during the early morning hours on the 1st, before tapering off to spotty freezing drizzle during the afternoon and evening.
Every event with a place to put it; 31 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CTP wrote it up.
A large winter storm brought periods of snow, sleet and freezing rain to central Pennsylvania. The initial round of mixed wintry precipitation (mainly snow and sleet) occurred during the early morning hours on the 1st, before tapering off to spotty freezing drizzle during the afternoon and evening. A steadier and much heavier round of freezing rain mixed with sleet overspread the region from the late evening on the 1st and continued until the early morning on the 2nd. A minor snow and sleet accumulation of 2 to 4 inches was common near and to the north of Interstate 80. Significant ice accumulations between one quarter to three quarters of an inch were observed over nearly the entire area.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS State College, PA wrote its last area forecast discussion before the first event at Jan 31, 10:20 PM EST, 2 hours 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1020 PM EST MON JAN 31 2011 .SYNOPSIS... A MESSY AND LONG-DURATION WINTER STORM WILL MOVE IN OVERNIGHT. THE STORM HAS THE POTENTIAL TO PRODUCE HEAVY SNOW ACROSS THE NORTHERN TIER OF PENNSYLVANIA...WITH A WINTRY MIX OF SNOW...SLEET AND FREEZING RAIN OVER CENTRAL AND SOUTHERN PARTS OF THE STATE. GUSTY WEST TO NORTHWEST WINDS IN THE WAKE OF THE STORM WILL CREATE SNOW SHOWERS OVER THE NORTHERN AND WESTERN MOUNTAINS WEDNESDAY NIGHT AND THURSDAY. HIGH PRESSURE BUILDS IN FOR FRIDAY BEFORE A STORM FORMS OVER THE DEEP SOUTH AND MOVES UP THE EAST COAST NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... PRECIP IS BEGINNING TO STREAK INTO THE AREA ON THE NOSE OF THE WARM ADVECTION. NEW OPERATIONAL NAM SHOWS WARM WEDGE ALOFT MOVING INTO SOUTHERN AREAS...FROM NORTHERN CAMBRIA TO SOUTHERN LANCASTER BY 12Z. HAVE ADJUSTED EXPECTED SNOW AMOUNTS OVERNIGHT DOWNWARD TO MATCH WHAT SHOULD BE A QUICK CHANGEOVER TO MIXED OR FREEZING PRECIP. DIDN'T TWEAK MUCH BEYOND THAT. 21Z SREF PLUMES CONTINUE TO ADVERTISE A SIGNIFICANT ICING THREAT WHILE DOWNPLAYING SNOW AMOUNTS SOUTH OF ABOUT I-80. MID SHIFT WILL HAVE A FULL SUITE OF PRODUCTS TO USE IN ADJUSTING SNOW AND ICE NUMBERS WITH THE EARLY MORNING PACKAGE. MIN TEMPS TONIGHT WILL RANGE FROM 10 TO 15 ACROSS THE NE MTNS...TO THE LOWER 20S ALONG THE MASON DIXON LINE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... SREF MEAN BALANCES SOME OF THE PRECIP TYPE AND AMOUNT DIFFERENCES SEEN IN THE OPERATIONAL NAM/GFS AND EC. LLVL THERMAL PATTERN OF THE SREF AND NAM LOOKS MORE REASONABLE WITH RESPECT TO COLD AIR DAMMING EAST OF THE ALLEGHENY PLATEAU. SREF AND NAM ALSO KEEP SFC TEMPS NEAR TO SLIGHTLY BELOW FREEZING FOR THE SECOND AND MORE SIGNIF ROUND OF THIS STORM LATER TUESDAY AND WEDNESDAY. THE STEADIER SNOW WILL DIMINISH TO PERIODS OF LIGHTER SNOW...SLEET AND EVEN SOME -FZRA FROM LATE TUES MORNING THROUGH EARLY TUESDAY EVENING. THIS WILL LEAVE A GOOD 6-10 HOUR PERIOD BETWEEN THE 2 SYSTEMS WHEN JUST LIGHT ADDITIONAL SNOW...AND/OR ICE ACCUMS WILL OCCUR. STEADY AND HEAVIER SNOW/SLEET WILL QUICKLY OVERSPREAD THE AREA FROM THE SW EARLY TUESDAY NIGHT AND CONTINUE THROUGH WED MORNING. THE PRECIP WILL BE MAINLY SLEET AND FREEZING RAIN TO THE SOUTH OF INTERSTATE 80. HOWEVER...MULTIPLE TRANSITIONS IN PRECIP TYPE WILL LIKELY OCCUR ACROSS CENTRAL PENN...SINCE THE WEDGE OF MILDER AIR ALOFT /BETWEEN 850 AND 750 MB/ COULD BE JUST 1-2 DEG C ABOVE ZERO IN A SHALLOW LAYER MEANDERING AROUND INTERSTATE 80. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... AS THE WARM AIR ADVECTS NORTHWARD THE SECOND PHASE OF THIS EVENT WILL BEGIN. COLD AIR DAMMING AT THE SURFACE WILL KEEP SURFACE TEMPS BELOW FREEZING AT FIRST AS A STRONG WARM SECTOR MOVES IN ALOFT. MOST MODELS SHOW A WARM LAYER FROM 3 TO 5 THOUSAND FEET ABOVE THE SURFACE. AT THE HIGHER ELEVATIONS SPECIFICALLY THE LAUREL HIGHLANDS THERE WILL BE PERIODS OF ABOVE FREEZING TEMPS. THE NAM AND SREF RUNS HAVE SHOWN A COOLING TREND...WITH A WEAKER WARM SECTOR. THIS SECTOR LOOKS TO REMAIN WARM ENOUGH TO ALLOW FOR PERIODS OF RAIN TO FREEZING RAIN AND SLEET TUESDAY NIGHT. SURFACE TEMPS WILL DROP BELOW FREEZING LATE TUESDAY AFTERNOON BEFORE A PERIOD OF FREEZING RAIN AND SLEET. THE SYSTEM WILL TRANSITION TO SNOW. THE PRIMARY LOW TRAVERSES THROUGH THE REGION DURING THE DAYLIGHT HOURS ON WEDNESDAY. PRECIPITATION WILL TAPER OFF LATE WEDNESDAY. AS THE UPPER LEVEL LOW MOVES THROUGH THERE WILL BE A SHARP CHANGE IN TEMPERATURES AS A STRONG COLD FRONT MOVES THROUGH THE AREA WEDNESDAY AFTERNOON. WITH THIS STRONG TEMPERATURE GRADIENT THERE WILL BE STRONG GUSTY WINDS. WIND GUSTS COULD EXCEED 20 TO 30 MPH IN SOME AREAS WEDNESDAY AFTERNOON. THE TEMPS DROP SIGNIFICANTLY AND SHSN SHOULD BE LIKELY IN THE AFTN AND WEDNESDAY NIGHT. THE PREVIOUSLY ANTICIPATED BITTER COLD FOR THURS/FRI HAS NOW BEEN MODIFIED SLIGHTLY. IT WILL STILL BE COLD...BUT MINS BELOW 0F DOESN'T LOOK LIKE THE GREATEST PROBABILITY PER THE LATEST GUIDANCE. THE HIGH PRESSURE THAT BUILDS IN THURSDAY NIGHT THROUGH FRIDAY NIGHT CLEARS THE SKIES AND THERE COULD STILL BE COLD TEMPS..ESPECIALLY IF THE TRAJECTORIES OF THE NEW SNOW/ICE PACK OVER THE MIDWEST AND LOCAL LEAD TO/ALLOW LESS MODIFICATION TO THE AIRMASS THAN WOULD BE EXPECTED WITH BARE GROUND. ALL IN ALL...FRI LOOKS LIKE THE DRIEST DAY. THE NEXT SYSTEM WOULD BE A COASTAL LOW TO FORM ON FRIDAY OVER THE DEEP SOUTH AND RIDE UP THE COAST. THIS POTENTIAL WEEKEND STORM LOOKS MUCH MORE LIKE WHAT WE HAVE SEEN ALREADY THIS YEAR -ALL SNOW FOR THE REGION...WITH THE BEST CHANCE OF DEEP SNOW TO THE EAST OF STATE COLLEGE. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... A WEAK AREA OF LOW PRESSURE APPROACHING FROM THE MIDWEST WILL BRING DETERIORATING FLYING CONDS TO CENTRAL TONIGHT IN THE FORM OF FREEZING PRECIPITATION...LOW CIGS AND VSBYS. HEAVIEST PRECIP IS LOCATED OVER INDIANA/ILLINOIS AS OF 00Z AND MDL DATA SUGGESTS IT WILL OVERSPREAD CENTRAL PA BTWN 06Z-09Z. SREF AND MDL SOUNDINGS INDICATE PTYPE WILL BE SNOW ACROSS NORTHERN PA /BFD AND IPT/...WITH A WINTRY MIX OF FZRA AND SLEET ACROSS THE SOUTH. WIDESPREAD IFR CIGS/VSBYS ARE EXPECTED WHEN THE HEAVIER PRECIP ARRIVES LATE TONIGHT. AS CORE OF STRONGER WINDS ALOFT MOVE THRU TUE MORNING...LOW LEVEL WIND SHEAR CRITERIA MAY BE MET AT IPT...WHERE LOW LVL WIND IS CHANNELED BY THE TERRAIN. A LULL IN THE PRECIP IS EXPECTED TUE AFTN...AS LOW PRES SYSTEM PASSES EAST OF PA. HOWEVER...MOIST EASTERLY FLOW WILL REMAIN OVR THE AREA...LIKELY SUSTAINING WIDESPREAD LOW CIGS. A MUCH STRONGER STORM SYSTEM WILL APPROACH FROM THE OHIO VALLEY TUE NIGHT...BRINGING A MIX OF SLEET AND FZRA TO THE REGION ALONG WITH WIDESPREAD LOW CIGS. OUTLOOK... WED...AM WINTRY MIX/IFR CONDS...IMPROVING CONDS BY AFTN. THU-FRI...NO SIG WX EXPECTED. SAT...CHANCE OF SNOW. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 5 PM EST WEDNESDAY FOR PAZ004>006- 010>012-037-041-042. WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR PAZ017>019- 024>028-033>036-045-046-049>053-056>059-063>066. && SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...DANGELO/LAMBERT LONG TERM...DANGELO AVIATION...FITZGERALD
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 342 PM EST MON JAN 31 2011 PAZ004>006-010>012-037-041-042-012045- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-TIOGA- NORTHERN LYCOMING-SULLIVAN- 342 PM EST MON JAN 31 2011 ...WINTER STORM WARNING IN EFFECT FROM 1 AM TUESDAY TO 5 PM EST WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER STORM WARNING. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER STORM WARNING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. PAZ017>019-024>028-033>036-045-046-049>053-056>059-063>066-012045- CLEARFIELD-NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON- MIFFLIN-JUNIATA-SOMERSET-BEDFORD-FULTON-FRANKLIN-SOUTHERN CLINTON- SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR-NORTHUMBERLAND-COLUMBIA-PERRY- DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER- 342 PM EST MON JAN 31 2011 ...WINTER STORM WARNING IN EFFECT FROM 1 AM TUESDAY TO 1 PM EST WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER STORM WARNING. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. WINTER STORM WARNING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The national radar mosaic for the moment the first event began.
31 winter storm. Local standard time, as filed.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 2 to 4 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 2 to 4 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 2 to 4 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 2 to 4 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 2 to 4 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 2 to 4 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 1 to 2 inches on the 1st, with 0.25 inch of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 1 to 2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 1 to 2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation ranged from 1 to 2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1-2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1-2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1-2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1-2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1-2 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1-3 inches on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
A large winter storm produced periods of snow, sleet and freezing rain over the area. Snow and sleet accumulation was around 1 inch on the 1st, with 0.25 to 0.50 inches of ice on the 2nd.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2011Every state in 2011This day in weather historyWarnings in Pennsylvania, February 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 270858, 270859, 270860, 270861, 270862, 270863, 270864, 270865, 270866, 270867, 270868, 270869, 270870, 270871, 270872, 270873, 270874, 270875, 270876, 270877, 270878, 270879, 270880, 270881, 270882, 270883, 270884, 270885, 270886, 270887, 270888.