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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 280834 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 434 AM EDT SAT MAR 28 2015 .SYNOPSIS... A DEEP UPPER LEVEL TROUGH WILL SWING EAST ACROSS PENNSYLVANIA TODAY. THE UPPER LEVEL FLOW WILL BECOME MORE ZONAL NEXT WEEK LEADING TO A SLOW MODERATION IN TEMPERATURES. && .NEAR TERM /THROUGH TONIGHT/... ANOMALOUSLY DEEP AND COLD UPPER TROUGH IS DROPPING OUT OF THE EASTERN GR LAKES TO PASS PRETTY MUCH OVERHEAD EARLY TODAY. STRONG HEIGHT FALLS ALOFT HELPING SUPPORT AN AREA OF LARGE SCALE WEAK ASCENT. LOW LEVEL FLOW HAS BECOME WEAKLY CYCLONIC AND THE RAP SHOWS A SMALL AREA OF LOW LEVEL CONVERGENCE/FRONTOGENETIC FORCING THAT COINCIDES FAIRLY CLOSELY WITH THE LOCALIZED SNOW SHOWERS WE HAVE GOING ON FROM JUST EAST OF THE OFFICE OUT TO ABOUT WILLIAMSPORT. THE RAP WEAKENS THIS SLOWLY OVER THE NEXT SEVERAL HOURS AND STRETCHES IT OUT FROM NNW TO SSE AS THE UPPER LOW/HEIGHT FALLS SETTLE SOUTHEAST. GUIDANCE IN GOOD AGREEMENT WITH THE UPPER LOW/TROUGH MOVING OVERHEAD THIS MORNING HEADING OFF TO SE TO BE MOVING OUT OF PA BY LATE DAY. MODELS USE THE COLD AIR ALOFT TO CREATE AN AREA OF STEEP LAPSE RATES IN EXCESS OF 8C/KM FROM 850-700MB. I WOULD NORMALLY GET A LITTLE MORE EXCITED AT THIS TIME OF YEAR ABOUT LOW TOPPED THUNDER AND PERHAPS SMALL HAIL...BUT MODEL SOUNDINGS SHOW A GREAT DEAL OF DRY AIR ABOVE 700MB WHICH LIMITS DEEPER INSTABILITY. STILL WITH UPPER TEMPS SO COLD...IF WE CAN BREAK OUT WITH SOME SUNSHINE THIS MORNING INTO EARLY AFTERNOON...I WOULDN`T BE SURPRISED IF THERE ARE A FEW SQUAT STORMS. CONFIDENCE IS LOW HOWEVER. AT THIS POINT I USED A MODEL BLEND OF POPS SINCE THE SREF LOOKED TOO WET AND DISPLACED FROM THE BEST LAPSE RATES...AND THE MOS POPS LOOKED TOO LOW. BASICALLY ENDED UP WITH CHC POPS THIS MORNING INTO THE FIRST PART OF THE AFTERNOON WITH THE END OF THE DAY BECOMING DRY. I`LL STICK WITH MY ASSESSMENT FROM YESTERDAY ABOUT TODAY BEING THE COLDEST DAY WE WILL EXPERIENCE UNTIL LATER NEXT FALL OR EARLY WINTER. HIGHS FROM THE LOWER 20S TO MID 30S WILL BE SOME 20-30 DEG BELOW NORMAL. A GUSTY WIND WILL MAKE IT FEEL EVEN COLDER...MORE LIKE JANUARY THAN THE LAST DAYS OF MARCH. SKIES WILL CLEAR EARLY THIS EVENING ALLOWING TEMPS TO PLUNGE INTO THE SINGE NUMBERS OVER THE NORTH TO AROUND 20 OVER THE SOUTH. IF WINDS DROP OFF TO CALM...SOME READINGS NEAR ZERO COULD HAPPEN OVER THE FAR NORTH. && .SHORT TERM /SUNDAY/... SUNDAY WILL BE BRIGHT AND SUNNY WHICH WILL HELP TEMPERATURES REBOUND AFTER THE VERY COLD START TO THE DAY. HOWEVER HIGHS FROM THE MID 30S TO MID 40S...WHILE MILDER THAN TODAY...WILL STILL BE SEVERAL DEG BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... NAEFS CONTINUES TO ADVERTISE A BREAKDOWN OF THE WESTERN NOAM RIDGE WHICH EVENTUALLY TRANSLATES INTO A MORE ZONAL FLOW OVER THE EASTERN CONUS. BUT BEFORE THAT HAPPENS WE WILL HAVE AT LEAST A COUPLE OF SHORTWAVES THAT WILL KEEP CONDITIONS SOMEWHAT UNSETTLED AND ON THE COOL SIDE. THE FIRST SYSTEM IS A COLD FRONT THAT WILL BRING SOME LIGHT RAIN OR SNOW SHOWERS SUNDAY NIGHT INTO MONDAY...FOLLOWED BY A BOUT OF THE ALL TOO FAMILIAR CHILLY POST FRONTAL STRATOCU AND MOUNTAIN RAIN OR SNOW SHOWERS DURING THE DAY MONDAY. THIS IS FOLLOWED IN QUICK SUCCESSION BY ANOTHER SHORTWAVE FOR TUESDAY. THE OPERATIONAL GFS/ECMWF BOTH HAVE AN INTERESTING LOOKING SURFACE LOW THAT THEY TAKE SE THROUGH CENTRAL OR SOUTHERN PA ALONG A TIGHT THERMAL RIBBON. AT THIS TIME ALL I HAVE MENTIONED FOR PRECIP IS RAIN. FCST 850 TEMPS WOULD NORMALLY BE COLD ENOUGH TO CONSIDER SNOW AT LEAST NORTH OF THE LOW...BUT THE FACT IT IS COMING THROUGH DURING THE DAY AT THIS TIME OF YEAR...I AM RELUCTANT TO FORECAST SNOW WITH HIGHS EXPECTED IN THE 40S AND 50S. BY MIDWEEK WE SHOULD SEE UPPER HEIGHTS REBOUND AS THE MAIN TROUGH AT LEAST TEMPORARILY SHIFTS INTO THE CANADIAN MARITIMES. HOWEVER THE PARENT UPPER LOW REMAINS OVER HUDSON`S BAY AND EVEN DROPS SOUTH IN TIME...REINFORCING THE TROUGHING OVER THE NRN US BY WEEK`S END. BUT THE GOOD NEWS IS THE FLOW INTO THE LOCAL AREA WILL BE ORIGINATING OVER THE PACIFIC NW MORE THAN THE DEEP ARCTIC...SO TEMPS WHILE STILL EXPECTED TO BE BELOW NORMAL...SHOULD MOVE AWAY FROM THE EXTREME COLD WE HAVE ENDURED FOR SO MUCH OF THE TIME SINCE FEBRUARY. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... DEEP UPPER LEVEL LOW RESULTING IN DEFORMATION SNOW DEVELOPING BETWEEN UNV AND IPT AS OF 1 AM. MADE SOME CHANGES TO THE TAFS BASED ON THIS...HARD TO SEE MUCH CHANGE IN CONDITIONS UNTIL LATE AFTERNOON TODAY. AS THE COASTAL LOW PULLS AWAY SATURDAY NIGHT...BREEZY CONDITIONS WILL PREVAIL. MORE LESS THAN GREAT WEATHER WILL WORK BACK INTO THE AREA BY EARLY MONDAY MORNING. OUTLOOK... SUN...NO SIG WX/VFR. MON...CHANCE OF LIGHT RAIN /LIGHT SNOW EARLY/ ACROSS THE WESTERN HALF WITH MVFR REDUCTIONS. VFR SE. TUE...CHANCE OF LIGHT RAIN ACROSS NW HALF WITH MVFR REDUCTIONS. VFR SE. WED...MAINLY VFR...AS HIGH PRESSURE BUILDS INTO THE AREA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...LAMBERT/CERU/MARTIN

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