An area of low pressure originating along the Gulf Coast moved northeast over the Appalachians, producing a wintry mix of snow, sleet and freezing rain across central Pennsylvania. Heavy snow was observed over the Northwest Mountains with light to moderate snow and sleet accumulations common across the Central Mountains and Susquehanna Valley.
Every event with a place to put it; 25 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.
An area of low pressure originating along the Gulf Coast moved northeast over the Appalachians, producing a wintry mix of snow, sleet and freezing rain across central Pennsylvania. Heavy snow was observed over the Northwest Mountains with light to moderate snow and sleet accumulations common across the Central Mountains and Susquehanna Valley. Occasional freezing rain and drizzle resulted in a glaze of icing in most locations with significant ice accretion over the Lower Susquehanna Valley.
Widespread hazardous winter weather resulted in numerous vehicle accidents and road closures. Sporadic power outages were also reported across the region.
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 27, 3:32 PM EST, 2 hours 28 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 332 PM EST TUE JAN 27 2009 .SYNOPSIS... LOW PRESSURE WILL CONSOLIDATE ALONG A FRONTAL BOUNDARY...THAT STRETCHED FROM THE LOWER MISSISSIPPI VALLEY TO SOUTHERN APPALACHIANS...AND MOVE NORTHEAST OVER THE NEXT 36 HOURS. THIS STORM WILL TRACK JUST TO THE SOUTH OF PENNSYLVANIA WEDNESDAY AFTERNOON...AND BRING HEAVY SNOWFALL TO NORTHERN PENNSYLVANIA...WITH A SIGNIFICANT SNOWFALL FOLLOWED BY MIXED PRECIPITATION ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE STATE. A COLD FRONT WILL LIKELY MOVE THROUGH PENNSYLVANIA LATE FRIDAY...FOLLOWED BY A RIDGE OF HIGH PRESSURE AND NEAR NORMAL TEMPERATURES FOR THIS UPCOMING WEEKEND. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... WINTER STORM WARNING IS IN EFFECT THIS EVENING THROUGH WEDNESDAY FOR THE ENTIRE FORECAST AREA. THE WELL DEFINED...EAST/WEST ZONE OF FRONTOGENESIS IN THE 925 TO 850 HPA LAYER THAT BROUGHT A GENERAL 1 TO 2 INCHES OF SNOW TO SOUTHERN PENN EARLY TODAY HAS TEMPORARILY SETTLED JUST TO THE SOUTH OF THE MASON/DIXON LINE AT MIDDAY. EXPECT GENTLE OVERRUNNING/WARM ADVECTION VIA THE INCREASING SOUTHWESTERLY FLOW ALOFT TO SPREAD LIGHT SNOW BACK ACROSS THE SW PART OF OUR CWA LATE IN THE DAY/EARLY THIS EVENING...BEFORE IT ADVANCES NE ACROSS THE REGION AND BECOMES STEADIER AND HEAVIER TONIGHT. TEMPERATURES THROUGH LATE THIS EVENING WILL STAY WITHIN A FEW DEGREES OF THEIR CURRENT LATE AFTERNOON READINGS THANKS TO THE LOWERING/THICKENING CLOUD COVER AND NEUTRAL...TO WEAK WARM ADVECTION AT LLVLS. && .SHORT TERM /11 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SIMILAR TO SEVERAL OTHER STORMS THIS WINTER...WE ARE FACED WITH QPF AND RESULTANT SNOW/ICE ACCUMULATION TEETERING ON THE THRESHOLD OF WARNING CRITERIA (BOTH WITH RESPECT TO AMOUNT...AND TIME DURATION). MORE SPECIFICALLY...THERE IS HIGH CONFIDENCE THAT WE SEE 6 TO 8 INCHES ACROSS MUCH OF THE NORTHERN MOUNTAINS OF PENN...BUT IT MAY OCCUR OVER SLIGHTLY MORE THAN A 12 HOUR PERIOD. SEVERAL INCHES OF SNOW...FOLLOWED BY A SIGNIFICANT PERIOD OF SLEET (WITH POTENTIALLY 0.25-0.35 OF ICING) WILL OCCUR TO THE SOUTH OF INTERSTATE 80 WHERE A BLEND OF THE 12Z NAM AND WRFARW INDICATES THE NRN EXTENT OF THE 800-850 HPA WET BULB SLIDING ACROSS THE AREA NEAR OR JUST TO THE NORTH OF INTERSTATE 80 DURING THE MID TO LATE MORNING HOURS WED. BEST CHC FOR HEAVY FZRA ACCUMULATION WILL BE ACROSS THE LAUREL HIGHLANDS DURING THE MID MORNING HOURS OF WEDNESDAY. 15Z SREF PLUMES REMAIN VERY SIMILAR IN TYPE AND PRECIP AMOUNTS WHEN COMPARED TO ITS PAST SEVERAL RUNS AT ALL GRID POINTS. AGAIN...THE MOST NOTICEABLE INCREASE HAS BEEN IN THE FZRA/SLEET CATEGORY ACROSS THE SOUTHERN ZONES. THE MAIN REASONING FOR FALLING OFF THE FENCE AND ENDING UP ON THE WARNING SIDE OF THE EVENT WILL BE THE WIDESPREAD HIGH IMPACT OF THE STORM...WITH THE GREATEST PRECIP RATES (OF AROUND 0.10+ PER HOUR) DURING THE PEAK MORNING COMMUTE HOURS AND JUST PRIOR TO THAT TIME PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... PRECIP WILL BE QUICKLY TAPERING OFF FOR MOST WED EVE AS STORM RAPIDLY MOVES INTO NEW ENGLAND. BUT SCATTERED SNOW SHOWERS WILL LINGER OVR THE ALLEGHENIES THRU THURSDAY AS RESIDUAL MOISTURE ASCENDS THE HIGH TERRAIN. OTHERWISE...PARTIAL CLEARING EXPECTED EAST OF MTNS AS HIGH PRESSURE RIDGE BUILDS INTO THE REGION. TEMPS WILL REMAIN SEVERAL DEGREES BELOW NORMAL /WITH LARGER RANGES AT NIGHT/ BUT NOT BE BITTERLY COLD AS SEEN EARLIER THIS MONTH. SCATTERED SNOW SHWRS COULD ACCOMPANY A COLD FRONTAL PASSAGE LATE FRIDAY...MAINLY IN THE HIGHER TERRAIN. HOWEVER...SFC RIDGE BUILDS IN QUICKLY SAT...INDICATING LITTLE CHC FOR MUCH LAKE EFFECT. COULD BE A BREEZY DAY ON SAT. A SHORT PERIOD OF MODERATING TEMPS STILL APPEARS LIKELY SUN/MON AHEAD OF THE NEXT WAVE. BOTH THE GFS AND ECMWF IN AGREEMENT ON TROUGH AND POTENTIAL NEXT STORM ARRIVING TUE-WED OF NEXT WEEK SO POPS ABOVE CLIMO. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... LATEST SFC OBS INDICATE THAT THE HIGH PRESSURE OVER THE REGION REMAINS STRONG AND CIGS AND VSBYS ARE ALL VFR. THE HIGH WILL SLIDE A BIT TO THE EAST THIS EVENING...AS THE WARM ADVECTION FROM THE GATHERING STORM BEGINS TO LOWER PRESSURES OVER THE OH VALLEY. THE SNOW SHOULD BEGIN AROUND OR SLIGHTLY AFTER 00Z...AS THE 150+KT WINDS ALOFT QUICKLY SPREAD IT NORTH AND EAST. THIS SNOW WILL QUICKLY DROP THE CIGS AND VSBYS THIS EVENING TO IFR...AND HOLD THEM THERE THROUGH MOST OF WED. THE PRECIP TYPE WILL CHANGE TO SLEET AND PERHAPS THEN TO FREEZING RAIN IN ALMOST ALL TERMINALS EXCEPT KBFD DURING THE LATE NIGHT OR EARLY WED AM. KJST MAY SEE A PROLONGED PD OF FZRA OVERNIGHT AND WED AM. A DRY SLOT MAY MOVE IN WED MORNING AS THE MAIN SFC LOW CROSSES JUST TO THE SOUTH OF THE AREA...BUT AN INVERTED TROUGH OR EVEN A SECONDARY LOW CENTER WILL SLIDE OVERHEAD. THIS COULD TURN MOST PRECIP TO FZDZ OR EVEN PLAIN RAIN BEFORE THE COLD AIR MOVES BACK IN AND TURNS THE PRECIP BACK TO SNOW FROM NW TO SE WED AFTN/EVENING. AGAIN...CIGS WILL REMAIN IFR THROUGH MOST OF WED. VSBYS MAY BOUNCE UP AFTER THE MAIN SLUG OF PRECIP MOVES BY US LATE WED AM. WED NIGHT THROUGH FRIDAY LOOKS TYPICAL FOR POST-FRONTAL NW FLOW...GENERALLY IFR IN UPSLOPE SNOW SHOWERS N&W AND MVFR CENTRAL WITH MDT/LNS MOST LIKELY VFR. SOME LINGERING SHSN IN THE WEST SAT...BUT FAIR/VFR OVER THE REST OF THE AREA. SUNDAY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 8 PM EST WEDNESDAY FOR PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066. && SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...RXR AVIATION...DANGELO
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 1258 PM EST TUE JAN 27 2009 PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066-281800- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD- NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON-MIFFLIN- JUNIATA-SOMERSET-BEDFORD-FULTON-FRANKLIN-TIOGA-NORTHERN LYCOMING- SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR- NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND- ADAMS-YORK-LANCASTER- 1258 PM EST TUE JAN 27 2009 ...WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO 8 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...WEDNESDAY THROUGH MONDAY. 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... WEATHER SPOTTERS ARE REQUESTED TO REPORT SNOW AND ICE ACCUMULATIONS TO THE NATIONAL WEATHER SERVICE IN STATE COLLEGE. LAMBERT
The national radar mosaic for the moment the first event began.
25 winter storm. Local standard time, as filed.
Eight to twelve inches of snow was reported across Warren County.
Six to ten inches of snow was reported across McKean County.
Three to six inches of snow and sleet along with a light glaze of ice was reported across Potter County.
Three to six inches of snow and sleet along with a light glaze of ice was reported across Elk County.
Three to six inches of snow and sleet along with a light glaze of ice was reported across Cameron County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Northern Clinton County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Northern Centre County.
Three to six inches of snow and sleet along with a moderate ice accretion was reported across Clearfield County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Tioga County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Northern Lycoming County.
Two to four inches of snow and sleet along with a moderate ice accretion was reported across Southern Lycoming County.
Three to six inches of snow and sleet along with a light glaze of ice was reported across Sullivan County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Northumberland County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Montour County.
Two to four inches of snow and sleet along with a light glaze of ice was reported across Columbia County.
Two to four inches of snow and sleet along with a moderate ice accretion was reported across Schuylkill County.
One to three inches of snow and sleet along with a moderate ice accretion was reported across Perry County.
One to three inches of snow and sleet along with a moderate ice accretion was reported across Cumberland County.
One to three inches of snow and sleet along with a moderate ice accretion was reported across Franklin County.
One to three inches of snow and sleet along with a moderate ice accretion was reported across Adams County.
One to three inches of snow and sleet along with a significant ice accretion was reported across York County.
One to three inches of snow and sleet along with a significant ice accretion was reported across Dauphin County.
One to three inches of snow and sleet along with a significant ice accretion was reported across Lebanon County.
Two to four inches of snow and sleet along with a significant ice accretion was reported across Cambria County.
Two to four inches of snow and sleet along with a significant ice accretion was reported across Somerset County.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2009Every state in 2009This day in weather historyWarnings in Pennsylvania, January 2009
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: 143907, 143908, 143909, 143910, 143911, 143912, 143913, 143914, 143915, 143916, 143917, 143918, 143919, 143920, 143921, 143922, 143923, 143924, 143925, 143926, 143927, 143928, 143929, 143930, 143931.