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 220911 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 511 AM EDT TUE JUL 22 2014 .SYNOPSIS...
-- Changed Discussion --
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER PENNSYLVANIA TODAY. A POTENT COLD FRONT WILL MOVE SOUTHEAST FROM THE GREAT LAKES AND CROSS THE COMMONWEALTH LATE WEDNESDAY AND WEDNESDAY NIGHT. A REFRESHINGLY COOLER AND LESS HUMID AIRMASS WILL OVERSPREAD THE COMMONWEALTH FOR THE END OF THE WEEK INTO THE WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
1022 MB SFC HIGH PRES CENTERED NEAR KPHL /WITH A RIDGE EXTENDING TO ITS NW/ WAS PROVIDING TRANQUIL CONDITIONS ACROSS THE CWA EARLY THIS MORNING. TEMPS...MAINLY IN THE MID TO UPPER 60S...WERE A FEW DEG F ABOVE NORMAL FOR AN EARLY MORNING LOW. A DISTINCT...AND NEARLY NORTH/SOUTH AXIS OF HIGH THETA-E AIR WITHIN THE 925-850 MB LAYER /AND PWATS AROUND 1.5 INCHES/ CREATED A RATHER EXTENSIVE LAYER OF STRATUS/STRATOCU ACROSS THE CENTRAL AND EASTERN ZONES. EXPECT THESE CLOUDS TO PERSIST IN A BKN-OVC LAYER THROUGH 13 OR 14Z. AFTER THE EARLY TO MID MORNING LOW CLOUDS AND PATCHY FOG MIXES OUT...TODAY WILL FEATURE NOTICEABLY WARMER TEMPERATURES AS AN UPPER RIDGE SLIDES EAST FROM THE GRT LKS. HIGHS MONDAY WERE IN THE M/U80S UPSTREAM OVR MICHIGAN AND EXPECT SIMILAR READINGS THROUGHOUT THE VALLEYS OF CENTRAL PA THIS AFTERNOON. THE HIGHER TERRAIN OF THE ALLEGHENY PLATEAU WILL LIKELY ONLY REACH THE L80S. DIURNAL HEATING SHOULD RESULT IN MODERATELY HIGH CAPES THIS AFTN...HELPING TO DEVELOP JUST A FEW PULSE-TYPE SHRA/TSRA DURING THE MID TO LATE AFTN. THE BEST CHC FOR THE ISOLATED CONVECTION SHOULD BE ACROSS SOUTHERN PA AND PERHAPS THE LOWER SUSQ VALLEY...WHILE SURGING MID LVL TEMPS /EXCEEDING 9C AT 700 MB/ OVR NW PA MAY COMPLETELY SUPPRESS CONVECTION UP THERE.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
-- Changed Discussion --
SIMILAR /AND PERHAPS EVEN MUGGIER/ CONDITIONS ARE EXPECTED FOR TONIGHT WITH A LIGHT SOUTHERLY FLOW AND 1.5 INCH PWAT AIR KEEPING TEMPS ABOUT 6-8F ABOVE NORMAL. VERY WARM MID LEVEL TEMPS /AVERAGING 9C AT 700 MB OVER CENTRAL PENN/ WILL KEEP CONDITIONS DRY TONIGHT THROUGH MUCH OF WEDNESDAY MORNING. THE ARRIVAL OF A STRONG COLD FRONT AND UPPER LEVEL DISTURBANCE WEDNESDAY AFTERNOON AND EVENING WILL CREATE SEVERAL BANDS OF DEEP UVVEL...HELPING TO BREAK THIS CAP AND FIRE OFF ONE OR MORE BKN LINES OF STRONG TO POTENTIALLY SVR TSRA. SPC HAS THE ENTIRE CWA IN THEIR DAY 2 /SEE TEXT/ OUTLOOK. GIVEN THE PROJECTED HIGH CAPE AND WEAK-MDT DEEP LAYER SHEAR TYPE OF ENVIRONMENT THE PRIMARY STORM TYPE WILL BE PULSE AND MULTI-CELL CLUSTERS CAPABLE OF PRODUCING LOCALIZED SVR HAIL AND WET MICROBURSTS /WITH A FEW MIN-BOW ECHOES POSSIBLE AS WELL/ WEDNESDAY AFTERNOON THROUGH EARLY WED EVENING. THANKS TO A WARMING/LLVL...WSW DOWNSLOPE FLOW AHEAD OF THE CFRONT...HIGH TEMPS WED WILL BE THE WARMEST OF THE WEEK...RANGING FROM THE LOWER 80S ACROSS THE HIGHEST TERRAIN OF THE NORTH AND WEST...TO THE MID AND UPPER 80S IN THE CENTRAL VALLEY...AND LOWER 90S IN THE GREATER YORK/HARRISBURG AREA.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
-- Changed Discussion --
OVERALL SCENARIO REMAINS UNCHANGED IN THE LONG TERM PERIOD AS A LARGE UPPER RIDGE BUILDING OVER THE FOUR CORNERS REGION IS FORECAST TO EXPAND NORTH AND EAST INTO THE ROCKIES AND PLAINS DURING THE PERIOD. DOWNSTREAM...THIS WILL LEAD TO LONG WAVE TROFFING OVER THE EASTERN THIRD OF THE COUNTRY. UPPER LOW TO THE EAST OF HUDSON BAY WILL BE STRENGTHENED AT TIMES BY SHORTWAVE ENERGY IN THE STRONGER JET STREAM FLOW ACROSS CANADA. SOUTHWARD EXTENSION OF THIS LOW/TROF WILL AT TIMES DURING THE PERIOD STRENGTHENING THE TROFFING ACROSS THE NORTHEASTERN U.S./OUR REGION. TODAYS TREND OF MEDIUM RANGE MODEL GUIDANCE IS FOR STRONGER/DEEPER TROFFING DOWNSTREAM ACROSS THE EASTERN U.S...DEVELOPING AN ALMOST FULL LATITUDE TROF EXTENDING FROM THE EASTERN CANADA LOW SWD TO FLORIDA. THIS WILL LIKELY SERVE TO EXPAND AND PROLONG THE CHANCES FOR PCPN THIS WEEKEND. GUIDANCE FORECASTS CONTINUE TO BRING A FRONT AND INCREASED CHANGES FOR PRECIPITATION TOWARD PA IN THE WEDNESDAY/THURSDAY TIME FRAME AND SHOW A SECOND...POTENTIALLY STRONGER SYSTEM LATE NEXT WEEKEND. THE TREND OF STRONGER TROUGHING MENTIONED ABOVE HAS LEAD TO SLOWER ARRIVAL AND DEPARTURE OF THE FRONTAL SYSTEM IN THE DAILY PROGS. A WARM FRONT WILL BE ON THE DOORSTEP OF PA SUNDAY MORNING...A BIT SLOWER THAN FORECAST YESTERDAY. HAVE THUS ADJUSTED POPS/TIME TO SUIT. ASSOCIATED COLD FRONT DOES NOT CROSS THE STATE TIL MONDAY AT THIS POINT...LEADING TO A POTENTIAL PROLONGED PERIOD OF SHOWERS AND THUNDERSTORMS. AT THIS TIME FRAME HOWEVER...A LOT WILL LIKELY CHANGE BEFORE WE REACH NEXT WEEKEND.
-- End Changed Discussion --
&& .AVIATION /09Z TUESDAY THROUGH SATURDAY/... NOCTURNAL COOLING OF RATHER MOIST BLYR /SFC DEWPTS IN THE LOW-MID 60S/ COMBINED WITH NEARLY CALM WINDS WILL ALLOW FOR EXPANSION OF LOW CIGS AND REDUCED VISBYS IN FOG/BR EARLY THIS MORNING ACRS CNTRL PA AIRSPACE. WHILE A PERIOD OF IFR CONDS CANNOT BE RULED OUT PRIOR TO DAYBREAK...KEPT ALL TERMINALS AOA MVFR USING A BLEND OF PERSISTENCE AND CURRENT TRENDS WITH GUIDANCE AND LAST NGTS OBS. EXPECT VISBYS TO IMPROVE FASTER THAN CIGS THIS MORNING WITH VFR LKLY BY 17-18Z. WARMING TEMPS ALOFT AND VIRTUALLY NO SYNOPTIC FORCING SUGGESTS VERY LOW PCPN PROBS FOR THE AFTN/EVE. HOWEVER..THERE WILL LKLY BE ENOUGH INSTABILITY AND MOISTURE TO PRODUCE AN ISOLD TSTM OR TWO WITH THE HIGHER TERRAIN PERHAPS ACTING AS TRIGGER. NO MENTION OF PCPN IN TAFS AS POINT PROBS/CVRG WILL BE VERY LOW/SPARSE. DIURNAL CU SHOULD FACE AFTER DARK WITH SOME PATCHY FOG DEVELOPING OVRNGT. OUTLOOK... WED...SCT TSTM IMPACTS LKLY ASSOCD WITH COLD FRONT. THU...SCT TSTM IMPACTS PSBL SERN AIRFIELDS AS COLD FRONT SLOWS AS IT APPROACHES THE MID-ATLC COAST. FRI-SAT...PATCHY A.M. FOG PSBL. OTHRWISE NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT/GARTNER AVIATION...STEINBUGL

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