Central PA - Severe Threat

[NeffsvilleWx]

 

 ZCZC SPCSWOD48 ALL   ACUS48 KWNS 270930   SPC AC 270930      DAY 4-8 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0330 AM CST SUN JAN 27 2013      VALID 301200Z - 041200Z      ...DISCUSSION...   THERE IS REASONABLE AGREEMENT AMONGST THE LATEST SUITE OF GUIDANCE   THAT A POWERFUL AND HIGHLY AMPLIFIED UPPER TROUGH WILL MAKE RAPID   PROGRESS TOWARD THE ERN SEABOARD THROUGH LATE D4/WEDNESDAY. A MID   LEVEL WIND MAX IN EXCESS OF 100KT IS FORECAST TO ROTATE THROUGH THE   BASE OF THE TROUGH FROM THE TN VALLEY TO THE MID ATLANTIC COINCIDENT   WITH THE ADVANCING COLD FRONT ACROSS THESE AREAS. MODELS ALSO   SUGGEST THAT LOW AND DEEP-LAYER MOISTURE WILL INCREASE RAPIDLY   IMMEDIATELY AHEAD OF THE FRONTAL ZONE WITH ECMWF DEPICTING A PLUME   OF AT LEAST 1.5 INCH PW VALUES EXTENDING AS FAR NORTH AS PHL AREA BY   WEDNESDAY EVENING. QPF AND VERTICAL MOTION FIELDS FROM LATEST EC AND   GFS MODELS SUGGEST A CONTINUATION AND/OR RESURGENCE OF CONVECTION   ALONG NEARLY THE ENTIRE FRONT AMIDST INTENSE CLOUD-BEARING SHEAR.   WHILE CAPE ACROSS MUCH OF THE RISK AREA WILL REMAIN LOW...EXPECT   BOUNDARY LAYER WARMING/MOISTENING TO BECOME SUFFICIENT ENOUGH TO   SUPPORT THE DOWNWARD TRANSPORT OF HIGH MOMENTUM AIR TO THE SURFACE   WITH DAMAGING WINDS EXPECTED TO ACCOMPANY THE PASSAGE OF THE   CONVECTIVE LINE.      THE STRONG COLD FRONT SHOULD BE CLEAR OF ALL BUT FAR SRN FL BY   D5/THURSDAY. COLD AND DRY AIR IN THE WAKE OF THIS SYSTEM APPEARS TO   SHUT DOWN FURTHER PROSPECTS FOR STRONG TO SEVERE TSTMS AT LEAST   THROUGH THE REMAINDER OF THE WEEK.      ..CARBIN.. 01/27/2013