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 200000 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 800 PM EDT SUN APR 19 2015 .SYNOPSIS... AN APPROACHING FRONTAL SYSTEM WILL BRING A SOAKING RAIN TO THE REGION TONIGHT AND EARLY MONDAY. ADDITIONAL SHOWERS AND SCATTERED STRONG...TO POTENTIALLY SEVERE THUNDERSTORMS WILL DEVELOP ALONG AND AHEAD OF A COLD FRONT AS IT PUSHES EAST ACROSS THE STATE MONDAY AFTERNOON AND EVENING. A LARGE UPPER LEVEL LOW WILL SET UP OVER ONTARIO AND QUEBEC FOR THE MIDDLE AND LATTER PART OF THE WEEK...USHERING IN UNSEASONABLY COOL AIR WHICH WILL LAST INTO THE WEEKEND OR LONGER. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... CLOUDS ARE THICKENING AHEAD OF THE RAIN THAT IS DEVELOPING OVER MY SOUTHWESTERN ZONES. THE RAIN WILL CONTINUE NORTHEASTWARD REACHING A BRADFORD TO STATE COLLEGE TO YORK LINE BY AROUND 01-02Z...THEN ACROSS THE SUSQ VALLEY BETWEEN 03Z-05Z. A STEADY SOAKING RAIN IS IN STORE FOR MUCH OF TONIGHT AS THE AXIS OF A HIGHLY ANOMALOUS...APPROX 4 SIGMA...SOUTH-SOUTHEASTERLY LLJ SLIDES NE ACROSS THE REGION...WITH PWATS OF 1-1.5 INCHES FALLING IN THE PLUS 2-3 SIGMA RANGE. THE BEST CHANCE FOR OVER 1 INCH OF RAIN TONIGHT WILL BE FOUND ACROSS THE CENTRAL AND SCENT MTNS. HIGHEST PROBABILITY OF THE 1 INCH/12 HOURS WILL BE ACROSS THE LAURELS AND SOUTHERN TIER COUNTIES. THERE`S ACTUALLY A SMALL AREA OF LOW PROBABILITY FOR UP TO 2 INCHES ALONG THE EASTERN SLOPES AND CREST OF THE LAURELS. IF RAINFALL AMOUNTS DO REACH 2 INCHES IN THAT 12 HOUR PERIOD...THERE COULD BE SOME SMALL STREAM...MAINLY MINOR FLOODING CONCERNS. TEMPS THROUGHOUT THE NIGHT TONIGHT WILL BE 7-10F ABOVE NORMAL...WITH MINS EARLY MONDAY IN THE MID 40S TO LOWER 50S. SOUTHEAST SFC WINDS WILL BE GUSTY AS AN AXIS OF 60-70 KT S-SE WIND IN THE 3-5 KFT AGL LAYER MOVES EAST ACROSS THE REGION. TYPICALLY MOST RESIDENTS OF CENTRAL PA DO NOT GET MUCH IN THE WAY OF STRONG WIND GUSTS DURING STABLE SERLY FLOW RAIN EVENTS. HOWEVER...SOME BORDERLINE WIND GUSTS OF 40 TO 45 MPH WILL BE POSSIBLE ON THE RIDGE TOPS...AND JUST TO THE NORTH OF THESE HIGHER RIDGE-LINES /AND GAPS IN THOSE SAME RIDGES/. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... THE STEADY STRATIFORM...WARM FRONTAL RAINS GRADUALLY TAPER OFF THEN END FOR A WHILE DURING THE MID TO LATE MORNING HOURS. THE WARM FRONT WILL LINGER ACROSS THE CENTRAL MTNS AND LOWER TO MID SUSQ VALLEY MONDAY AFTERNOON AND EARLY EVENING. HOWEVER...THE STRONG LOW AND MID LEVEL FLOW AND APPROACHING STRONG COLD FRONT /AND LEFT EXIT REGION OF AN UPPER LEVEL JETLET/ WILL COMBINE WITH THE 1-1.5 INCH PWATS TO TRIGGER ADDITIONAL TSRA MON AFTERNOON AND EVENING. ADDITIONAL RAINFALL AMOUNTS FROM THIS CONVECTION WILL AVERAGE 0.25 TO 0.50. THE POTENTIAL EXISTS FOR SKIES TO AT LEAST PARTIALLY CLEAR DURING PEAK HEATING MONDAY ACROSS SOUTHERN PA. SHOULD THIS OCCUR...MANY CONVECTIVE AND SHEAR PARAMETERS...NEAR AND JUST SOUTH OF THE QUASI STNRY FRONT...ACROSS SCENT PENN AND THE MIDDLE-LOWER SUSQ VALLEY WILL COMBINE TO BRING THE POTENTIAL FOR SVR TSRA. THE MAIN SVR THREAT WILL BE ISOLATED LARGE HAIL AND LOCALIZED DAMAGING STRAIGHT-LINE WIND GUSTS. HOWEVER...WITH EHI`S IN THE 2-4 M2/S2 RANGE NEAR THE I-81 CORRIDOR BETWEEN 19Z MONDAY AND 00Z TUESDAY...THE POTENTIAL EXISTS FOR SOME SUPERCELLS AND ONE OR TWO TORNADOES CLOSE TO THE FRONTAL BOUNDARY. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... THE PATTERN WILL BE DOMINATED BY A LARGE UPPER LEVEL LOW MOVING THROUGH THE NORTHERN GREAT LAKES...AND THROUGH SOUTHERN CANADA MIDWEEK TO THE WEEKEND. THERE IS GOOD MODEL CONSENSUS THROUGH THE MID RANGE PERIOD. AFTER THE FRONT LIFTS OUT BY TUESDAY MORNING THE UPPER LOW HANGS AROUND S CANADA/NEW ENGLAND FOR SEVERAL DAYS KEEPING FAIRLY BRISK W/NW FLOW ACROSS PA. THIS WILL BRING A STEADY STREAM OF COLDER AIR AS TEMPS SLOWLY SLIP A BIT LOWER EACH DAY WITH BELOW NORMAL READINGS FOR A SEVERAL DAY PERIOD LINGERING INTO NEXT WEEKEND. PROXIMITY OF UPPER LOW WILL ALSO KEEP MENTION OF SCT SHOWERS IN THE FORECAST. A SHORTWAVE SHOULD DROP THROUGH THE REGION WEDNESDAY AFTERNOON INTO THURSDAY MORNING. THIS COULD DROP EVEN COLDER AIR INTO THE REGION BRINGING THE POSSIBILITY OF SNOW TO THE NW TO THE CENTRAL REGIONS OF PA. THE MODELS THEN DIVERGE ON A SOLUTION BUT THE UPPER LEVEL LOW SHOULD CONTINUE ITS EASTWARD TREK...WITH ONLY A SLIGHT CHANCE FOR PRECIPITATION NEXT WEEKEND. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS AT 00Z WILL TREND LOWER OVERNIGHT WITH WIDESPREAD MVFR TO IFR CIGS EXPECTED BY EARLY MONDAY MORNING. RAIN WILL CONTINUE TO OVERSPREAD THE AIRSPACE EARLY TONIGHT WITH MODERATE INTENSITY LKLY FOR A PERIOD LATE TONIGHT INTO EARLY MONDAY MORNING. THE STEADY RAIN SHOULD TAPER OFF FROM SW TO NE BTWN 12-15Z. A TIGHT PRESSURE GRADIENT WILL PRODUCE GUSTY WINDS FROM 120 TO 160 DEGREES...AND LOW LEVEL WIND SHEAR CONDITIONS GIVEN STRONG WINDS IN THE LOWEST FEW THOUSAND FEET AGL. THE WIND SHEAR WILL END IN A SIMILAR FASHION TO THE RAIN. ANTICIPATE MORNING RESTRICTIONS TO TREND TOWARD VFR BY THE EARLY AFTERNOON HOURS ON MONDAY. LOOK FOR MAINLY VFR TO CONTINUE INTO LATE IN THE DAY WHEN SCT STG TO LOCALLY SVR TSTMS MAY DEVELOP ALONG/AHEAD OF A COLD FRONT. FOR NOW HAVE INDICTED VCTS IN THE LAST FM GROUP...BUT AS CONFIDENCE CONTINUES TO BUILD LATER ISSUANCES MAY ADD A TEMPO GROUP TO SHOW THE MOST LKLY TIMING FOR TSTM IMPACTS ON LOCAL TAF AIRFIELDS. OUTLOOK... TUE-FRI...PERSISTENT NW FLOW PATTERN EACH DAY WILL FAVOR MVFR CIGS OVER THE NW AIRSPACE IN ZOB SECTOR...WITH MAINLY VFR CONDITIONS PREVAILING IN ZNY DOMAIN. SCT SHOWERS WILL BE POSSIBLE ACROSS ALL OF THE AIRSPACE THROUGH THE REMAINDER OF THE WEEK. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT LONG TERM...CERU/RXR AVIATION...STEINBUGL

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