National Weather Service discussion this AM - MEANWHILE...THERE IS A GOOD CONSENSUS THAT REGARDLESS OF THE FATE OF AN EARLY MORNING MCS...THE ATMOSPHERE ACROSS THE MID-ATLANTIC WILL SUFFICIENTLY DESTABILIZE AND BE PRIMED FOR WHAT COULD BE A SIGNIFICANT SEVERE WEATHER EVENT DURING THE AFTERNOON AND EARLY EVENING. AN UNSEASONABLY STRONG SURFACE LOW WILL MOVE FROM THE OHIO VALLEY INTO SOUTHERN PENNSYLVANIA THURSDAY AFTERNOON. WARM FRONTAL BOUNDARY LOOKS BE DRAPED ACROSS NORTHEAST MARYLAND...WHILE A COLD FRONT APPROACHES THE APPALACHIANS. MODELS SHOW STRONG SYNOPTIC LIFT ACROSS THE CWA...JOINED BY DECENT DESTABILIZATION DURING THE AFTERNOON AND LIKELY CONTRIBUTING TO STRONG LAPSE RATES AND CAPE AOA 2000 J/KG. MODELS ALSO INDICATE STRONG VERTICAL WIND SHEAR ACROSS THE CWA /BULK SHEAR GTE 50 KT/. THESE FACTORS WILL RESULT IN WIDESPREAD THUNDERSTORMS DURING THE AFTERNOON...SOME PRODUCING DAMAGING/DESTRUCTIVE WIND GUSTS...LARGE HAIL AND ALSO A FEW TORNADOES. IN ADDITION...THUNDERSTORMS WILL BE CAPABLE OF PRODUCING FLASH FLOODING. PRECIPITABLE WATER VALUES ARE NOT FORECAST TO BE QUITE AS HIGH AS A FEW DAYS AGO...BUT RECENT RAINFALL HAS RESULTED IN LOW FLASH FLOOD GUIDANCE ACROSS MUCH OF THE CWA /EXCEPT PERHAPS THE NORTHWEST CORNER/. THIS ANTECEDENT CONDITION COMBINED WITH THE EXPECTATION FOR HEAVY DOWNPOURS FROM THUNDERSTORMS MAY LEAD TO FLASH FLOODING IN SOME AREAS. A FLASH FLOOD WATCH MAY BECOME NECESSARY.
Posted on: Wed, 12 Jun 2013 13:34:42 +0000