Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 261219 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 819 AM EDT SAT JUL 26 2014 .SYNOPSIS... A SERIES OF DISTURBANCES WILL MOVE ACROSS THE FORECAST AREA THIS WEEKEND AS A DEEP UPPER TROUGH DEVELOPS OVER THE NORTHEASTERN UNITED STATES. THERE WILL BE SEVERAL CHANCES FOR PRECIPITATION BEFORE ANOTHER SHOT OF UNSEASONABLY COOL AIR MOVES IN AND REMAINS OVER THE REGION THROUGHOUT THE NEW WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... SHORTWAVE SLIDING EAST OUT OF CWA AT 12Z...TAKING MUCH OF THE SHOWER ACTIVITY ALONG WITH IT AS RIDGING ALOFT WILL PROVIDE A RESPITE IN THE SHOWER ACTIVITY. AS A RESULT...FORECASTED BELOW MODEL POPS AS HEIGHTS ALOFT RISE AHEAD OF THE NEXT TROUGH THAT WILL BE DIGGING INTO THE GR LAKES. MID LEVEL LAPSE RATES WILL BE FAIRLY STEEP SO I CANNOT RULE OUT A STRAY SHOWER OR T-STORM...BUT THINKING IS THAT COVERAGE WILL BE SMALL ENOUGH TO AVOID MENTION IN MOST AREAS. 850 TEMPS POP UP TO 16-18C WHICH SHOULD BE SUITABLE FOR DAYTIME HIGHS TO HIT 80 OR ABOVE OVER MOST OF THE AREA. MORE CLOUDS UP NORTH WILL PROBABLY KEEP READINGS IN THE UPPER 70S. HUMIDITY WILL BE ON A SLOW RISE...BUT NOT TERRIBLE GIVEN THAT WE ARE IN THE HEIGHT OF THE CLIMATOLOGICAL SUMMER. SPC HAS A MODERATE RISK FOR A GOOD CHUNK OF IL-IN EXPECTING AN MCS TO FORM AHEAD OF A COLD FRONT THAT WILL BE MOVING INTO THE MIDWEST. THESE DEVELOPMENTS WILL HAVE TO BE CLOSELY MONITORED FOR SOUTHWESTERN SECTIONS LATER TONIGHT AS MODELS SHOW A RARE LATE NIGHT SURGE OF INSTABILITY MOVING INTO WESTERN AREAS. WITH CONVECTIVE PLACEMENT CONFIDENCE BEING LOW AT THIS RANGE...I OPTED FOR CHANCE POPS CENTERED MAINLY AFTER MIDNIGHT. && .SHORT TERM /SUNDAY/... SUNDAY COULD BE A BUSY DAY AS AN UNSEASONABLY STRONG UPPER LOW DROPS THROUGH THE LOWER LAKES AND TAKES AIM AT THE LOCAL AREA. SPC HAS OUTLOOKED MUCH OF KY AND WV WITH A MODERATE RISK WHICH LOOKS REASONABLE GIVEN THE STRENGTH OF THE APPROACHING DYNAMICS AND INSTABILITY. WE COULD BE VULNERABLE LOCALLY INTO THE EVENING GIVEN THE EXPECTED TIMING OF THE COLD FRONT ENTERING THE REGION AND THE AMOUNT OF UPSTREAM INSTABILITY THE SYSTEM WILL HAVE AVAILABLE. WHERE THE OHIO VALLEY DEVELOPMENTS TAKE PLACE WILL HAVE MUCH TO SAY ABOUT HOW FAR NORTH INTO CENTRAL PA THE STRONGEST STORMS WILL MANAGE TO MOVE. AS USUAL...BEING ABOUT 2 DAYS OUT...THIS REMAINS MURKY BUT THIS IS A REMARKABLY ROBUST SYSTEM FOR MID SUMMER AND IT WILL BE SURPRISING IF IT PASSES WITHOUT CAUSING SEVERE STORMS. GIVEN CURRENT PROJECTIONS OF WIND AND INSTABILITY...THE AREA SOUTH OF I-80 WOULD SEEM TO BE THE REGION MOST UNDER THREAT FOR SEVERE WEATHER. HIGHS IN THE UPPER 70S TO MID 80S WILL BE TRENDING DOWN OVER THE NEXT FEW DAYS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... ALL THE ACTION OF NOTE WILL BE PRETTY MUCH OVER BY MONDAY WITH POST FRONTAL SHOWERS GRADUALLY DIMINISHING IN COVERAGE AS THE LOW AND FRONT SLIDE THROUGH NEW ENGLAND. IN A PATTERN THAT LOOKS MORE LIKE IT BELONGS IN MID WINTER THAN MID SUMMER...AN ANOMALOUSLY DEEP UPPER TROUGH IS MADE TO SET UP OVER THE EASTERN US AND REMAIN IN PLACE ALL WEEK. THE DETAILS OF MINOR SHORTWAVES SLIDING INTO THE TROUGH DIFFER AMONG THE AVAILABLE GUIDANCE...BUT DEEP MOISTURE WILL HAVE MOVED EAST SO WE`LL BE LEFT DEALING WITH MAINLY DIURNAL INSTABILITY UNDER THE COLD AIR ALOFT. WE COULD SEE MORE SIGNIFICANT MOISTURE RETURN LATER IN THE WEEK AS THE GFS/GEFS/ECMWF ALL HINT AT THE UPPER TROUGH RETROGRADING A BIT...POSSIBLY PAVING THE WAY FOR SOME ATLANTIC MOISTURE TO WORK UP THE EASTERN SEABOARD. 500MB HEIGHTS IN THE 3-4STD DEV BELOW NORMAL RANGE AND 850 TEMPS OF 1-3 STD DEV BELOW NORMAL POINT TO THE MOST CERTAIN PART OF THE FORECAST BEING SEVERAL DAYS OF TEMPERATURES AVERAGING WELL BELOW NORMAL. A SLOW MODERATION CAN BE EXPECTED BY LATE IN THE WEEK. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... NOT A LOT OF CHANGE FOR THE 12Z TAFS. ONE THING TO NOTE IS THAT THERE IS STILL PROBLEMS WITH THE AOO OB. ANYWAY...SEVERAL MORE HOURS OF WIDELY SCATTERED SHOWERS...BUT CONDITIONS SHOULD REMAIN VFR. SHOWERS SHOULD END BY LATE MORNING...AS VORT MAX MOVES EAST OF THE AREA. ANOTHER JET MAX MOVES ACROSS THE AREA THIS EVENING. THUS COULD BE A FEW MORE SHOWERS ACROSS THE NORTHERN AND WESTERN AREAS TONIGHT. THE COMBINATION OF DIRECTIONAL SHEAR AND WARM ADVECTION WILL LIKELY RESULT IN SOME STORMS BEING ON THE STRONG SIDE AT TIMES FROM SUNDAY INTO MONDAY. LOOKING AT MAINLY DRY CONDITIONS AFTER MONDAY. OUTLOOK... SUN...SCT TSRA IMPACTS EXPECTED. MON...AM LOW CIG POSS W MTNS. TUE-WED...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN

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