Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280735 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 235 AM EST SAT FEB 28 2015 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE AREA FOR THE FIRST HALF OF THE WEEKEND. A LOW PRESSURE SYSTEM WILL LIFT OUT OF THE MIDWEST...BRINGING SNOW AND MIXED PRECIPITATION TO CENTRAL PENNSYLVANIA SUNDAY AND SUNDAY NIGHT. A STRONGER AREA OF LOW PRESSURE WILL LIKELY TRACK WEST OF PENNSYLVANIA IN THE MIDDLE OF THE WEEK...PRODUCING ANOTHER ROUND OF MIXED PRECIPITATION AND RAIN IN CENTRAL PENNSYLVANIA. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... WIND HAS GONE CALM ACROSS THE NW MTNS...ALLOWING TEMPS TO PLUMMET LATE THIS EVENING. AT 05Z...MESONET OBS INDICATE THE COLDER VALLEYS OF THE NW MTNS HAVE ALREADY DROPPED TO ARND -15F. ACROSS THE EASTERN HALF OF THE STATE...A LIGHT BREEZE HAS KEPT TEMPS FROM FALLING TOO QUICKLY. HOWEVER...AS HIGH PRES BUILDS IN...EXPECT DIMINISHING WIND AND PLUMMETING READINGS TOWARD DAWN. HAVE TWEAKED MIN TEMPS A BIT...WITH LOWS AVERAGING FROM ARND -15F OVR THE NW MTNS...TO 0-5F ACROSS THE LOWER SUSQ VALLEY. HOWEVER...GIVEN THE IDEAL RAD COOLING CONDS...EXPECT A WIDE RANGE IN LOWS FROM HILLTOPS/URBAN LOCATIONS TO NORMALLY COLDER RURAL VALLEYS. A BIT OF THIN CIRRUS WILL OVERSPREAD THE AREA EARLY THIS AM IN RESPONSE TO DEVELOPING WAA ALOFT. HOWEVER...IT SHOULD NOT SIGNIFICANTLY AFFECT RAD COOLING. REC MIN FOR THE 28TH IS -18F AT IPT AND -1F AT MDT. EVEN THE -1F AT MDT SEEMS LIKE A LONG SHOT GIVEN CURRENT READINGS. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SUNDAY/... FAIR AND STILL COLD WEATHER EXPECTED SATURDAY...AS SFC HIGH WILL BE RIGHT OVERHEAD. A FAST-MOVING MID LVL SHORTWAVE IS PROGGED BY ALL MDLS TO TRACK ACROSS THE AREA LATE IN THE DAY. LOW PWAT AIR MASS WILL PRECLUDE ANY PRECIP CONCERNS. HOWEVER...CIRRUS MAY DIM THE SUNSHINE AT TIMES. ENS MEAN 850/925MB TEMPS REMAIN WELL BLW NORMAL FOR THE DATE...LIKELY SUPPORTING HIGHS ONLY IN THE 20-25F RANGE. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A RELATIVELY MILD/ACTIVE SOUTHWEST FLOW ALOFT SHOULD PREVAIL THROUGH THE PERIOD AS THE PERSISTENT UPPER RIDGE OVER THE WRN U.S. TEMPORARILY BREAKS DOWN. NUMEROUS SHORTWAVES WITHIN THE NRN AND SRN STREAMS WILL MOVE EAST DURING THE PERIOD PROVIDING POTENTIAL FOR PRECIPITATION...SOME OF IT RAIN...FOR A CHANGE. AN ARCTIC HIGH PRESSURE SYSTEM OVER CENTRAL PA AT THE START OF THE PERIOD WILL MOVE EAST OF THE REGION BY SUNDAY NIGHT. THE COMBINATION OF SHORTWAVE ENERGY IN THE SRN STREAM EJECTING FROM A TROUGH AND A DIGGING NRN STREAM TROUGH MOVING SEWD FROM SOUTH CENTRAL CANADA TOWARD THE UPPER MIDWEST SEEMS TO DRIVE AN EXPANDING AREA OF WAA TYPE SNOWFALL SPREADING EASTWARD SUN-MON. WHILE THERE APPEARS TO BE LITTLE INDICATION OF A STRONG SURFACE LOW...MODELS STILL GENERATE 0.25-0.50 INCH QPF AMTS ALONG THE BAROCLINIC ZONE. THERMAL PROFILES SEEM TO FAVOR SNOW ACROSS THE NW 1/2 OF CENTRAL PA WITH MIXED PTYPES POSSIBLE IN THE SOUTH/SOUTHEAST. MEDIUM RANGE...ENSEMBLE AND WPC GUIDANCE SUGGEST SUFFICIENT QP FOR A SIGNIFICANT SNOW EVENT ACROSS PART OF CENTRAL PA. ACCORDINGLY...HAVE ISSUED A WINTER STORM WATCH ACROSS THE NORTHWEST MOST 5 COUNTIES STARTING LATE SATURDAY NIGHT/EARLY SUNDAY MORNING THROUGH MONDAY MORNING. ANOTHER NRN/SRN STREAM COMBO LOOKS TO AFFECT THE REGION MID WEEK AS ENERGY FROM THE SRN CAL UPPER LOW BEGINS TO EJECT EWD. TIMING DIFFERENCES ARE EVIDENT WITH THE GFS MORE BULLISH ON PCPN RETURNING EARLY TUE VS. SLOWER ECMWF (TUE NGT). MIXED PTYPE ISSUES ARE EXPECTED AGAIN WITH THIS NEXT SYSTEM...WITH A LEAN TOWARD RAIN AS SIGNIFICANT WARM AIR MOVES NORTH AHEAD OF THE SYSTEM. BEHIND THE MID WEEK SYSTEM...ANOTHER PUSH OF ARCTIC AIR WILL BRING TEMPS AND POPS BACK WELL BELOW NORMAL FOR LATE THURSDAY INTO FRIDAY. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
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LARGE 1044MB SURFACE HIGH PRESSURE AREA WILL KEEP CONDITIONS VFR INTO SAT NIGHT...WITH LITTLE MORE THAN SOME HIGH CLOUDINESS PASSING OVERHEAD. WINDS WILL BE LIGHT THROUGH THIS PERIOD. CONDITIONS WILL DETERIORATE LATER SATURDAY NIGHT INTO SUNDAY...AS THE COMBINATION OF SHORTWAVE ENERGY IN THE SRN STREAM EJECTING FROM A TROUGH AND A DIGGING NRN STREAM TROUGH MOVING SEWD FROM SOUTH CENTRAL CANADA TOWARD THE UPPER MIDWEST BEGINS TO DRIVE AN EXPANDING AREA OF WAA TYPE SNOWFALL SPREADING IN FROM THE OHIO VALLEY. CLOUDS THICKEN AND LOWER...AND SNOW DEVELOPS FROM WEST TO EAST ACROSS THE AREA. THE SNOW IS EXPECTED TO CHANGE TO A WINTRY MIX ACROSS SRN PA ON SUNDAY. THINGS SHOULD BEGIN TO IMPROVE ON MONDAY AND REMAIN GOOD INTO EARLY TUESDAY...BEFORE THE NEXT SYSTEM PUSHES ANOTHER ROUND OF PRECIP AND REDUCED FLYING CONDS INTO THE AREA LATER TUE INTO WED. OUTLOOK... SAT NIGHT-SUN...SNOW OVERSPREADING THE AREA FROM W TO E. PRECIP SHOULD REMAIN ALL SNOW ACROSS NRN PA...WHILE MIXING W/ SLEET AND FREEZING RAIN ACROSS THE SOUTH. MON...CONTINUED CIG/VIS REDUCTIONS POSSIBLE...MAINLY AM. TUE...VFR AM. MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE LATE. TUE NIGHT-WED...CIG/VIS REDUCTIONS CONTINUE IN WINTRY MIX/RAIN.
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&& .CLIMATE... THE COLDEST FEBRUARY ON RECORD IS STILL LOOKING LIKELY. MONTHLY MEAN TEMPERATURES THROUGH THE 26TH...IPT 18.2...MDT 20.7. THE CURRENT RECORD COLDEST FEBRUARY..IPT 19.3...MDT 21.4 BOTH SET IN 1934. SO FAR...THIS MONTH IS THE THIRD COLDEST EVER AT IPT...AND FOURTH COLDEST EVER AT MDT. && .EQUIPMENT... KMDT AND KIPT TEMPERATURES READING FAR TOO WARM. OBSERVER AT KMDT REPORTED 27F AS THE MAX BASED ON BACKUP OBSERVATION AND NEAREST NEIGHBOR. PARTS ON ORDER FOR KMDT BUT KIPT TEMP SPIKE/TROUBLE IS NEW TODAY AND WILL BE INVESTIGATED. USING 28F FOR MAX IN KIPT FOR TODAY 2/27 BASED ON NEAREST NEIGHBOR OBSERVATIONS. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR PAZ004-005-010-011-017. && $$ SYNOPSIS...LAMBERT NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD LONG TERM...FITZGERALD/GARTNER AVIATION...RXR CLIMATE... EQUIPMENT...

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