Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | 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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 052043 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 343 PM EST THU MAR 5 2015 .SYNOPSIS... A WAVE OF LOW PRESSURE WILL TRACK SOUTH OF PENNSYLVANIA BY LATER TODAY AND THIS EVENING. 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 AM FRIDAY MORNING/... HAVE CANCELED PART OF THE WEATHER ADVISORY...OTHERWISE THE NEAR TERM FORECAST HAS NOT CHANGED. AS OF MID DAY THE MOST INTENSE MESOSCALE SNOW BAND EXTENDS FROM FRANKLIN COUNTY THROUGH LEBANON COUNTY. MORE OR LESS ON TRACK WITH RAP PLACEMENT AND TIMING OF BEST FRONTOGENTIC FORCING. HRRR SHOWS THE SNOW GRADUALLY SETTLING SOUTHEAST OVER THE NEXT 2-4 HOURS...WITH A RAPID TAPERING OFF AFTER 21Z. THIS SUPPORTS FINAL SNOW TALLIES IN THE 6-10 INCH RANGE ON AVERAGE. DRIER AIR AND HIGH PRESSURE WILL BUILD IN FOR THE OVERNIGHT LEADING TO YET ANOTHER NIGHT OF WIDESPREAD LOWS OF ZERO OR BELOW. AT THIS POINT...WE ARE COUNTING ON THE WIND TO DROP OFF ENOUGH TO MINIMIZE WIND CHILLS... SO NO HEADLINES ARE PLANNED AT THIS TIME. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... HIGH PRESSURE WILL PROVIDE A MUCH BRIGHTER DAY FRIDAY. FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SOME STRATOCU TO GATHER UNDER THE STRONG SUBSIDENCE INVERSION...BUT A FAIR AMOUNT OF SUNSHINE SHOULD MANAGE TO MIX WITH ANY CLOUDS THAT FORM. ONCE AGAIN IT WILL BE MUCH COLDER THAN NORMAL WITH HIGHS GENERALLY IN THE 20S. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
SFC HIGH PRESSURE RIDGE AXIS WILL MIGRATE EWD ACROSS THE MID ATLANTIC REGION FRIDAY NIGHT AND SETTLE INTO THE SOUTHEAST STATES ON SATURDAY. AN INCREASE IN SW GRADIENT WINDS AND CLOUDS ARE EXPECTED ACROSS THE NW HALF OF THE CWA IN ADVANCE OF A WEAK LOW MOVING ACROSS THE GREAT LAKES. MEANWHILE MAINLY CLEAR SKIES AND LIGHTER WINDS ACROSS THE LOWER SUSQ VALLEY SHOULD PREVAIL NEAR THE DEPARTING SFC RIDGE. THIS PATTERN FAVORS A NON-DIURNAL TREND WITH LOWS IN THE MID TEENS OCCURRING EARLY ACROSS THE NW MTNS FRIDAY NIGHT WITH A STEADY TO SLOW RISE INTO SATURDAY MORNING. A MORE TYPICAL NOCTURNAL TEMP CURVE SHOULD ALLOW TEMPS TO FALL TO AROUND 10F OVER THE LOWER SQV. BROAD UPPER CYCLONIC FLOW WILL CONTINUE INTO EARLY NEXT WEEK AS ADDITIONAL SHORTWAVE IMPULSES MOVE FROM CENTRAL CANADA THROUGH THE NORTHERN TIER OF THE U.S. THERE ARE FEWER DIFFERENCES NOTED OVERALL COMPARED TO PREVIOUS MODEL CYCLES WITH RESPECT TO THE TIMING AND DEPTH OF EACH IMPULSE. ONE IMPULSE WILL DRIVE A SURFACE WAVE AND ASSOCIATED FRONT THROUGH THE GREAT LAKES REGION ON SAT AND THEN INTO NEW ENGLAND ON SUN. AN ADDITIONAL IMPULSE WILL TAKE A SIMILAR TRACK THROUGH THE GREAT LAKES LATER SUN INTO EARLY MON ALONG WITH A WEAK FRONT. GIVEN THE FAST DEEPER LAYER WEST NORTHWEST FLOW OVER THE REGION...THE AMPLITUDE OF EACH IMPULSE SHOULD BE RATHER SMALL WITH MOISTURE AVAILABILITY QUITE LIMITED. THEREFORE EXPECT OCCASIONAL SNOW SHOWERS MAINLY OVER THE HIGHER TERRAIN OF THE NORTHERN ALLEGHENIES WITH 48 ACCUMS OF 1-2" POSSIBLE OVER THE NW MTNS BY 12Z MON. THE MODELS AND ENSEMBLE MEANS ARE AGREEABLE/CONSISTENT WITH THE MAIN THEMES OF THE LARGE SCALE PATTERN INTO NEXT WEEK. THESE INCLUDE AN INCREASINGLY ZONAL/PROGRESSIVE NRN STREAM FLOW ACROSS SRN CANADA...AND SRN ROCKIES/PLAINS INTO MEXICO MEAN TROUGH AND STRONG RIDGE E OF THE BAHAMAS. AS THE MEAN PATTERN ALOFT BECOMES INCREASINGLY FLATTER...CONFIDENCE IS RELATIVELY HIGH IN A MAINLY DRY PERIOD WITH STEADILY INCREASING/MODERATING TEMPERATURES TO AT OR SLIGHTLY ABOVE EARLY-MID MARCH CLIMATE NORMALS.
-- End Changed Discussion --
&& .AVIATION /20Z THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
MOST OF THE FLYING AREA WILL REMAIN VFR NORTH OF THE BANDED PRECIPITATION THAT IS CAUSING MVFR-IFR/LIFR FROM JOHNSTOWN EAST THROUGH THE LOWER SUSQ VALLEY. CONDITIONS WILL SLOWLY IMPROVE OVER SOUTHERN AND SOUTHEASTERN AREAS THIS AFTERNOON...WITH LANCASTER-HARRISBURG LIKELY BEING THE LAST TO ENJOY IN THE IMPROVING CONDITIONS. EXPECT MOST TERMINALS TO BE VFR OVERNIGHT. JST MAY BE THE EXCEPTION WITH LOW CLOUDS HANGING IN TOUGH UNDER THE UPSLOPE FLOW. OUTLOOK... FRI-SAT...MAINLY VFR. SUN-MON...MVFR WITH CHC -SHSN MAINLY NORTH AND WEST. VFR SE. TUE...NO SIG WX.
-- End Changed Discussion --
&& .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR PAZ036- 057>059-063>066. WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR PAZ033>035. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...STEINBUGL AVIATION...LA CORTE

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