Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 051300 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 800 AM EST THU MAR 5 2015 .SYNOPSIS... A WAVE OF LOW PRESSURE WILL TRACK SOUTH OF PENNSYLVANIA THIS MORNING. HIGH PRESSURE WILL BUILD SOUTHEAST INTO THE STATE FRIDAY AND SATURDAY. A STRONG UPPER-LEVEL RIDGE WILL BUILD INTO THE REGION EARLY NEXT WEEK. THIS SHOULD PROVIDE GENERALLY FAIR WEATHER AND SEVERAL DAYS OF NEAR NORMAL TEMPERATURES AND RELATIVELY DRY WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WATER VAPOR/SATL DERIVED PWAT IMAGERY SHOWING AN ATMOSPHERIC RIVER OF ANOMALOUS PWATS EXTENDING FROM THE S PACIFIC OCEAN NEWRD INTO THE MISS VALLEY AND EVENTUALLY PA AND THE NEW ENGLAND STATES. THIS DEEP MOISTURE PLUME IS OVERRUNNING AN EXPANSIVE ARCTIC HIGH PRES TO THE NORTH. ASIDE FROM SOME RAIN OR SLEET BEING MIXED IN FOR ANOTHER HOUR ACROSS FAR SOUTHERN YORK AND LANCASTER COUNTIES...BANDS OF LIGHT TO MDT SNOW WERE SEEN ON REGIONAL 88D MOSAIC ACROSS SOUTHERN PENN. AS A WEAK WAVE OF LOW PRESSURE AT THE SFC MOVES EAST ALONG THE NC/VA BORDER THIS MORNING /AND BANDS OF LOW-MID LEVEL FGEN TIGHTEN UP/STRENGTHEN BENEATH THE RIGHT ENTRANCE REGION OF A POWERFUL...165 KT UPPER JET/ SNOWFALL RATES ACROSS THE ADVISORY AND WARNING AREAS WILL INCREASE FOR SEVERAL HOURS...WITH BRIEF PERIODS OF 1/4-1/2SM VBSYS LIKELY ACROSS THE LOWER SUSQ REGION SOUTH OF THE I-81/I-78 CORRIDOR. EMPLOYING A HOST OF 00/03Z OPERATIONAL AND ENSEMBLE DATA...ALONG WITH HOURLY HIGH RES MODELS...WE TRIMMED THE WINT WEATHER ADVISORIES FROM MOST OF THE COUNTIES BORDERING INTERSTATE 80 /EXCEPT FOR NORTHUMBERLAND WHERE ITS NWD EXTENDING CHIMNEY WILL SEE MUCH LESS SNOW THAN SOUTHERN PORTIONS OF THE COUNTY WHERE 2-3 INCHES IS LIKELY/. OTHERWISE...A CONSENSUS BLEND OF LATEST HIGH RES AND ENS MODELS CONTINUE TO POINT TOWARD A GENERAL 2-4 INCH STORM TOTAL SNOWFALL ACROSS THE SOUTHERN COUNTIES BY THIS AFTERNOON...WITH PERHAPS A FEW AMTS UP TO 6 OR 7 INCHES TO THE SOUTH OF THE TURNPIKE IN THE LOWER SUSQ VALLEY...AND ON THE RIDGES OF SOMERSET COUNTY. 09Z TEMPS RANGED FROM THE MID TO UPPER TEENS OVER THE NW MTNS...TO THE LOWER 30S THROUGHOUT THE LOWER SUSQ VALLEY. COLDER AIR WILL CONTINUE TO FILTER INTO THE REGION ON NW FLOW...AND TEMPS WILL SLOWLY FALL ALL DAY THROUGHOUT CENTRAL PENN AND THE SUSQ VALLEY. BLEND OF LATEST MDL DATA INDICATE SNOW WILL TAPER OFF BY LATE AM ACROSS THE CENTRAL COUNTIES...AND MAY LAST UNTIL LATE AFTN ACROSS YORK/LANCASTER COUNTIES. ARCTIC HIGH AND ASSOC DRY AIR MASS WILL ARRIVE EARLY OVR THE NW COUNTIES...RESULTING IN DRY/COLD WX THE ENTIRE DAY UP THERE. SOME PARTIAL CLEARING APPEARS LIKELY ACROSS THE NW COUNTIES LATE IN THE DAY. ELSEWHERE...MDL SOUNDINGS INDICATE A MID LVL CLOUD DECK WILL LINGER EVEN AFTER THE SNOW ENDS. OVERCAST SKIES AND COLD ADVECTION WILL LIKELY BLUNT ANY DIURNAL WARMING AND RESULT IN STEADY TEMPS THRU EARLY AFTN...THEN FALLING TEMPS LATE. CONSALL OUTPUT SUPPORTS DAYTIME TEMPS FROM ONLY ARND 10F ACROSS THE NW MTNS...TO THE L20S ACROSS THE SOUTHEAST COUNTIES...ANOTHER EXCEPTIONALLY COLD DAY FOR THE TIME OF YEAR. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... HIGH PRESSURE AND BELOW NORMAL LOW-LEVEL TEMPERATURES WILL DOMINATE THE REGION TONIGHT INTO LATE FRIDAY. UNSEASONABLY COLD AIR...PERHAPS THE LAST OF THE SIGNIFICANT ARCTIC SURGES OF OUR ENDLESS WINTER. BASED ON THE LOW TEMPERATURES NEAR AND BELOW 0F AND THE WINDS...THE POTENTIAL EXISTS FOR SOME AREAS TO EXPERIENCE WIND CHILLS LOW ENOUGH LATE TONIGHT INTO FRIDAY WHICH MIGHT REQUIRE AN ADVISORY ACROSS THE NORTHERN TIER COUNTIES /AND PERHAPS EVEN THE LAUREL HIGHLANDS/. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... SFC HIGH PRESSURE RIDGE WILL SAG JUST TO THE SOUTH OF THE MID ATLANTIC REGION FRIDAY NIGHT...ALLOWING FOR AN INCREASE IN SWRLY SFC WINDS AND CLOUDS ACROSS THE NW HALF OF THE CWA...WITH MAINLY CLEAR SKIES AND LIGHTER WIND PERSISTING ACROSS THE LOWER SUSQ VALLEY...MUCH CLOSER TO THE SFC RIDGE. COLD TEMPS IN THE LOW-MID TEENS ACROSS THE NW MTNS FRIDAY WILL STAY NEARLY STEADY OR EVEN RISE A FEW DEG F FRIDAY NIGHT...WHILE A MORE NORMAL NOCTURAL TEMP DROP OF 12-15F IS EXPECTED ACROSS THE LOWER SUSQ VALLEY. SATURDAY THE TEMPERATURES AT 850 MB RETURN CLOSER TO NORMAL AND HIGH PRESSURE DRIFTS TO OUR SOUTH. PENNSYLVANIA SHOULD REMAIN NORTH OF THIS WEAK HIGH....CUTTING OFF ANY MOISTURE TO THE SOUTH...KEEPING THE REGION IN WEAK WESTERLY FLOW INTO MONDAY. THE PERIOD SHOULD BE RELATIVELY DRY WITH ANY FRONTAL PRECIPITATION SUPPRESSED TO OUR SOUTH AND ONLY WEAK NORTHERN STREAM WAVES TO OUR NORTH TO GENERATE ANY PRECIPITATION. SO...KEPT THE POPS LOW THROUGH THE PERIOD AND ANY LIGHT PRECIPITATION WOULD LIKELY BE SNOW AS 850 HPA TEMPS STAY BELOW 0C. BEST CHANCE OF ANY PRECIPITATION WOULD BE IN NORTHERN AREAS SHOULD ONE OF THE NORTHERN STREAM WAVES PROVE TO BE STRONGER THAN GUIDANCE IMPLIES. A RIDGE IS FORECAST TO BUILD OVER THE REGION TUESDAY INTO WEDNESDAY AND OUR LOWER TROPOSPHERE TEMPERATURES SHOULD GET AT LEAST SLIGHTLY....ABOVE NORMAL....BOTH TUESDAY INTO WEDNESDAY. THIS SHOULD PROVIDE AT LEAST 2 DAYS OF NEAR SEASONAL TEMPERATURES FOR A CHANGE. RELATIVELY WARM DAYS AND COLD NIGHTS...A GOOD SLOW WAY TO MELT SNOW WITHOUT FLOODING. THE NAEFSBC AND GEFSBC SUGGEST A FRONTAL PASSAGE THURSDAY WITH SLIGHTLY COLDER TEMPERATURES AS ANOTHER HIGH PRESSURE SYSTEM IS FORECAST TO MOVE OVER THE NORTHEASTERN UNITED STATES THURSDAY INTO SATURDAY NEXT WEEK. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... WIDESPREAD MVFR/IFR WILL CONTINUE ACROSS THE CENTRAL AND SRN AIRFIELDS THROUGH AT LEAST MID DAY TODAY BEFORE DRIER AIR BEGINS MOVING INTO THE REGION FROM THE WEST AND NORTH BRINGING IMPROVING CONDITIONS THIS AFTERNOON AND EVENING. NORTHERN SITES...ESPECIALLY KBFD MAY STAY MVFR OR HIGHER. EXPECT SKIES TO LIFT AND CLEAR OVERNIGHT. OUTLOOK... FRI-SAT...MAINLY VFR. SUN-MON...MVFR WITH CHC -SHSN MAINLY NORTH AND WEST. VFR SE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR PAZ024>028-034-035-050-052-056>059-063. WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR PAZ033- 036-064>066. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...GRUMM/LAMBERT AVIATION...CERU/GARTNER

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.