Area Forecast Discussion
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000 FXUS61 KPBZ 201828 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 228 PM EDT MON OCT 20 2014 .SYNOPSIS... RAINY AND COOL THROUGH MID-WEEK WHEN THE UPPER LOW PRESSURE SYSTEM SHIFTS EASTWARD. WARMER AND DRIER WEATHER IS EXPECTED TOWARDS THE END OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... SW TROF AND ATTENDANT VORT MAX EVIDENT ON WV IMAGERY CURRENTLY SWINGING THROUGH ERN INDIANA SOUTH OF THE SFC NEARING LAKE HURON. MID-LEVEL DEFORMATION PRODUCING HIGH CLOUDS AHEAD OF TROF AXIS OVER WV AND SW PA WILL PUSH EAST TONIGHT. THOSE CLOUDS WILL BE REPLACED BY LOWER CLOUDS THIS EVENING KEEPING TEMPS MODERATED. RADAR RETURNS HAVE BEEN QUITE NUMEROUS TODAY...BUT LITTLE MORE THAN VIRGA HAS BEEN REPORTED UP TO THIS POINT AS DRY AIR FROM THE MID LEVELS DOWN ARE KEEPING ANY RAIN SHOWERS FROM REACHING THE GROUND. RAIN SHOWERS ASSOCIATED WITH THE SW TROF ARE SHOWING UP OVER WRN OHIO AND ARE TIMED TO REACH OUR WRN PERIPHERY BY ABOUT 21Z. BY 00Z ALL OF THE NEAR TERM MODELS HAVE THE SW TROF AXIS THROUGH ERN OH WITH RAIN SHOWERS OVERSPREADING THE AREA FROM THE WNW. DEEPER MOISTURE AVAILABILITY AND BETTER FORCING WILL REMAIN CLOSER TO THE LOW NEAR LAKE ERIE...THUS WILL CONTINUE THE CATEGORICAL POPS THERE. ALTHOUGH THE MID TO UPPER LEVEL MOISTURE BEGINS TO OUTRUN THE TROF AXIS ACROSS OUR SOUTH...ENOUGH MOISTURE IS AVAILABLE TO PRODUCE SHOWERS ACROSS NRN WV. WILL NOT DEVIATE FROM THE LIKELY POPS. TONIGHT THE SFC LOW IS PULLED SOUTH AWAY FROM THE GREAT LAKES AS THE UPPER LOW BEGINS TO CUT-OFF. AS THIS HAPPENS...ABUNDANT LLVL MOISTURE WILL SHIFT OVER THE AREA KEEPING CLOUDS AND RAIN IN THE FORECAST. AS THE UPPER LOW SLOWLY PASSES TUES...THE SFC-H8 LOW CORE SHIFTS EAST BRINGING AN UPSLOPE COMPONENT TO THE LLVL WIND FIELD. WILL KEEP CATEGORICAL POPS IN FOR THE SE RIDGES AS A RESULT. DRIEST LOCATION IN THE CWA TUES LOOKS TO BE OVER ERN OHIO WHERE DRIER AIR ALOFT BEGINS FEEDING INTO THE UPPER LOW WHICH MAY WORK TO SUPPRESS ADDITIONAL SHOWERS. TAX && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A JET STREAK MOVG THROUGH THE WRN FLANK OF THE EWD SHIFT UPR TROF IS PROGGED TO CARVE A CUTOFF LOW OVR THE UPR OH VALLEY REGION BY LATE TUESDAY. COOLING MID LVLS WITH THAT SYSTEM WL LOWER CONVECTIVE THRESHOLDS AND SPPRT SHWR ACTIVITY THROUGH MIDWEEK...WITH PARTICULAR EMPHASIS OVR UPSLOPE REGIONS TO THE N AND E OF PITTSBURGH. BY THURSDAY...MDL WORLD PROJECTS SUFFICIENT COASTAL DVLPMNT/DEEPENING TO DIMINISH POPS OVR THE IMMEDIATE AREA...BUT CONFIDENCE IN SHRTWV/VORT PROJECTIONS THROUGH THE WRN QUADRANT OF THE SYSTEM IS MINIMAL...SO HAVE MAINTAINED AT LEAST SLGT POPS OVR THE RIDGES THROUGH THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... EWD PROGRESS OF THE AFOREMENTIONED UPR LOW WITH EXPANDING RIDGE OVR THE CNTRL CONUS SHOULD ENSURE A GENLY DRY AND SEASONABLY COOL CLOSE TO THE WEEK. TWEAKED WPC NMBRS WERE USED TO REPRESENT THE LONG TERM PD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS ARE EXPECTED WITH INCREASING CLOUDS THROUGH THIS EVENING AHEAD OF AN APPROACHING SHORTWAVE. THIS SHORTWAVE AND ASSOCIATED COLDFRONT IS EXPECTED TO BRING MVFR CONDITIONS AND INCREASING SHOWER CHANCES TONIGHT. AS THE UPPER LEVEL LOW PIVOTS AND DRIFTS SOUTH TUES LOW CLOUDS AND RAIN CHANCES ARE EXPECTED TO LINGER. MVFR CIGS MUCH OF TUES...BUT COULD SEE IFR IN ANY RAIN SHOWERS THAT PERSIST. .AVIATION /TUESDAY THROUGH FRIDAY/... PERIODIC RESTRICTIONS ARE POSSIBLE THROUGH MID WEEK AS AN UPPER LOW DRIFTS ACROSS THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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