A powerful storm system will continue to bring heavy mountain snow, rain, and high winds to the Pacific Northwest and northern California through midweek. Heavy rain and flash flooding potential exists across the central Gulf Coast over the next few days, including the Florida Panhandle. A Slight Risk (level 2 of 4) of excessive rainfall is in effect Tuesday. Read More >
Overview
A late season snow storm blanketed Central PA with a general 6 to 10 inches of snow on Friday the 16th, the day before St. Patrick's Day, 2007. This storm developed quickly, as it developed along an old frontal boundary that produced some rain (that combined with snow melt to cause minor flooding), and even ended as some slushy snow in the Northern PA counties on Thursday (the 15th). However, the front had pushed well off to the south and east of PA on Friday morning, and the primary low pressure center developed in the Carolinas during the day on Friday (the 16th), moving to the northeast. Despite the placement of the surface low on Friday morning (just deepening over South Carolina), the deep easterly flow of moisture into the state Thursday Night and Friday Morning began producing light snowfall in the southern half of the state before sunrise on Friday. The jet stream then dipped sharply to the south over the Appalachian Mountains, and intensified the storm rapidly during the day on Friday. The snow started as a fine, needle-like snow for most of the area, with rain falling in York and Lancaster. The rain changed to sleet, then to snow, during the daylight hours over those lower Susquehanna Valley Areas, with New Holland (Eastern Lancaster County) not changing completely to snow until 8 pm Friday. The rest of the region saw the heaviest of the snow fall during the Afternoon and Evening on Friday, as the also snow became a heavier, wetter, more-dendritic snow. See the Skew-T, Log-P diagrams below for representative atmospheric soundings for KLWX (Sterling, VA) and KPIT (Pittsburgh, PA) at 12z Friday (8 am) and 00z on Saturday (8 pm EDT Friday). Note the warm layer aloft on Friday morning at both LWX and PIT, which gets erased by the evening, showing the change to a snow-supportive sounding/atmosphere.Maps & Figures
Area Skew-T, Log-P Diagrams for 0000 UTC 3/17/2007 (8pm EDT, 16th) | Area Skew-T, Log-P Diagrams for 1200 UTC 3/16/2007 (8am EDT) | 2000UTC IR Satellite Picture 3/16/2007 (4pm EDT Friday) |
US Upper Air Chart (500HPa), Friday Morning (3/16/2007), 1200UTC (8am EDT) | US Surface Chart, Thursday Morning (3/15/2007), 1200UTC (8am EDT) | US Surface Chart, Friday Morning (3/16/2007), 1200UTC (8am EDT) |
Storm Reports
NOUS41 KCTP 171717 PNSCTP PAZ004>005-010>012-017>019-024>028-033>034-037-041>042-045>046- 049>053-056>059-063-065>066-180400- PUBLIC INFORMATION STATEMENT SPOTTER REPORTS NATIONAL WEATHER SERVICE STATE COLLEGE PA 115 PM EDT SAT MAR 17 2007 THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN DURING THE STORM THAT AFFECTED OUR REGION ON 16 MARCH 2007. APPRECIATION IS EXTENDED TO HIGHWAY DEPARTMENTS...COOPERATIVE OBSERVERS...SKYWARN SPOTTERS THE MEDIA...AND THE PUBLIC FOR THESE REPORTS. THIS SUMMARY IS ALSO ON OUR HOME PAGE AT WEATHER.GOV/CTP ********************STORM TOTAL SNOWFALL******************** LOCATION STORM TOTAL TIME/DATE COMMENTS SNOWFALL OF (INCHES) MEASUREMENT PENNSYLVANIA ...ADAMS COUNTY... GETTYSBURG 8.0 1200 PM 3/17 PENNDOT NEW OXFORD 9.0 100 AM 3/17 PUBLIC REPORT ORRTANNA 10.0 848 PM 3/16 PUBLIC REPORT YORK SPRINGS 9.7 700 AM 3/17 PUBLIC REPORT ...BEDFORD COUNTY... BUFFALO MILLS 5.9 700 AM 3/17 COOP REPORT EVERETTE 5.7 700 AM 3/17 COOP REPORT SAXTON 5.0 700 AM 3/17 COOP REPORT WOLFSBURG 5.0 700 AM 3/17 COOP REPORT ...BLAIR COUNTY... ALTOONA 4.8 700 AM 3/17 COOP REPORT TYRONE 4.0 700 AM 3/17 COOP REPORT WILLIAMSBURG 5.7 700 AM 3/17 COOP REPORT ...CAMBRIA COUNTY... JOHNSTOWN 7.8 400 AM 3/17 PUBLIC REPORT PRINCE GALLITZIN 8.3 700 AM 3/17 COOP REPORT ...CAMERON COUNTY... EMPORIUM 9.0 700 AM 3/17 COOP REPORT SINNEMAHONING 9.4 700 AM 3/17 COOP REPORT STEVENSON DAM 10.0 700 AM 3/17 COOP REPORT ...CENTRE COUNTY... BOALSBURG 8.0 932 PM 3/16 NWS EMPLOYEE CLARENCE 10.5 700 AM 3/17 COOP REPORT SPRING MILLS 9.0 632 AM 3/17 PUBLIC REPORT STATE COLLEGE 9.0 632 AM 3/17 PUBLIC REPORT PENN STATE 8.2 700 AM 3/17 COOP REPORT PHILIPSBURG 2S 7.7 700 AM 3/17 COOP REPORT ...CLINTON COUNTY... LOCK HAVEN 9.6 700 AM 3/17 COOP REPORT RENOVO 10.0 700 AM 3/17 COOP REPORT ...CUMBERLAND COUNTY... CARLISLE 8.6 917 AM 3/17 PUBLIC REPORT ENOLA 8.5 810 PM 3/16 PUBLIC REPORT NEW CUMBERLAND 8.0 857 PM 3/16 PUBLIC REPORT SHIPPENSBURG 6.2 700 AM 3/17 COOP REPORT SHIREMANSTOWN 10.5 923 PM 3/16 PUBLIC REPORT ...DAUPHIN COUNTY... DAUPHIN 8.3 800 AM 3/17 PUBLIC REPORT DEHART DAM 6.0 700 AM 3/17 COOP REPORT ELIZABETHVILLE 9.8 926 AM 3/17 PUBLIC REPORT HARRISBURG 9.0 221 AM 3/17 PUBLIC REPORT HARRISBURG AIRPORT 9.5 700 AM 3/17 COOP REPORT HARRISBURG 1NE 7.0 700 AM 3/17 COOP REPORT HERSHEY 8.0 700 AM 3/17 COOP REPORT MATAMORAS 7.0 700 PM 3/16 PUBLIC REPORT ...ELK COUNTY... RIDGWAY 5.0 700 AM 3/17 COOP REPORT ...FRANKLIN COUNTY... GREENCASTLE 6.0 811 PM 3/16 PUBLIC REPORT UPPPER STRASBURG 7.5 700 AM 3/17 COOP REPORT ...HUNTINGDON COUNTY... HUNTINGDON 7.0 700 AM 3/17 COOP REPORT ...LANCASTER COUNTY... GLEN MOORE 2.5 700 AM 3/17 COOP REPORT HOLTWOOD 5.0 700 AM 3/17 COOP REPORT MARIETTA 9.0 243 AM 3/17 PUBLIC REPORT MILLERSVILLE 7.0 812 PM 3/16 PUBLIC REPORT NEW HOLLAND 4.4 700 AM 3/17 COOP REPORT SAFE HARBOR 4.0 700 AM 3/17 COOP REPORT ...LEBANON COUNTY... LEBANON 12.0 1043 AM 3/17 PUBLIC REPORT PALMYRA 8.0 816 PM 3/16 PUBLIC REPORT ...LYCOMING COUNTY... HUGHESVILLE 10.4 700 AM 3/17 PUBLIC REPORT WILLIAMSPORT 9.7 700 AM 3/17 COOP REPORT ...MCKEAN COUNTY... CLERMONT 7.0 700 AM 3/17 COOP REPORT CYCLONE 6.0 855 PM 3/16 PUBLIC REPORT KANE 6.6 700 AM 3/17 COOP REPORT PORT ALLEGHENY 12.0 700 AM 3/17 COOP REPORT ...MONTOUR COUNTY... DANVILLE 7.0 700 AM 3/17 COOP REPORT ...NORTHUMBERLAND COUNTY... SHAMOKIN 12.0 812 PM 3/16 PUBLIC REPORT SUNBURY 7.6 700 AM 3/17 COOP REPORT ...PERRY COUNTY... NEW BLOOMFIELD 8.0 831 PM 3/16 PUBLIC REPORT ...POTTER COUNTY... BROOKLAND 13.0 800 AM 3/17 PUBLIC REPORT COUDERSPORT 13.5 851 PM 3/16 COOP REPORT GALETON 11.2 900 AM 3/17 PUBLIC REPORT ROULETTE 6.0 813 PM 3/16 PUBLIC REPORT ...SCHUYLKILL COUNTY... ASHLAND 9.2 1200 AM 3/17 PUBLIC REPORT MAHANOY CITY 10.2 700 AM 3/17 COOP REPORT PINE GROVE 9.0 700 AM 3/17 COOP REPORT SHENANDOAH HEIGHTS 10.6 800 AM 3/16 PUBLIC REPORT TAMAQUA 12.0 721 AM 3/17 PUBLIC REPORT ...SNYDER COUNTY... SELINSGROVE 8.0 700 AM 3/17 COOP REPORT ...SOMERSET COUNTY... CONFLUENCE 3.5 700 AM 3/17 COOP REPORT GLENCOE 6.1 700 AM 3/17 COOP REPORT LAUREL SUMMIT 7.5 700 AM 3/17 COOP REPORT MEYERSDALE 5.0 700 AM 3/17 COOP REPORT MOUNT DAVIS 5.3 700 AM 3/17 COOP REPORT SOMERSET 5.8 700 AM 3/17 COOP REPORT ...SULLIVAN COUNTY... LAPORTE 10.0 700 AM 3/17 COOP REPORT ...TIOGA COUNTY... COVINGTON 10.1 700 AM 3/17 COOP REPORT COWANESQUE DAM 7.0 700 AM 3/17 COOP REPORT GAINES 8.0 938 PM 3/16 PUBLIC REPORT SABINSVILLE 6.7 700 AM 3/17 COOP REPORT WELLSBORO 8.8 700 AM 3/17 COOP REPORT ...UNION COUNTY... LEWISBURG 7.0 700 AM 3/17 COOP REPORT LEWISBURG 10.0 1044 AM 3/17 PUBLIC REPORT MIFFLINBURG 10.5 800 AM 3/17 NWS EMPLOYEE ...WARREN COUNTY... CHANDLERS VALLEY 9.0 700 AM 3/17 COOP REPORT STARBRICK 6.0 100 PM 3/17 PENNDOT WARREN 5.0 848 PM 3/16 PUBLIC REPORT ...YORK COUNTY... DOVER 10.5 814 PM 3/16 PUBLIC REPORT HANOVER 10.4 213 AM 3/17 PUBLIC REPORT WELLSVILLE 10.0 815 PM 3/16 PUBLIC REPORT YORK HAVEN 6.0 700 AM 3/17 COOP REPORT YORK 11.5 814 PM 3/16 PUBLIC REPORT $$ CONNELLY
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