SWODY2
SPC AC 260522
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1222 AM CDT FRI OCT 26 2007
VALID 271200Z - 281200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
THE CLOSED LOW...WHICH BECAME CUT-OFF EAST OF THE LOWER MISSISSIPPI
VALLEY...IS NOW IN THE PROCESS OF LIFTING NORTH NORTHWESTWARD INTO
THE MIDDLE MISSISSIPPI VALLEY. AND...A NORTHEASTWARD ACCELERATION
IS FORECAST BY MODELS LATER TODAY INTO SATURDAY...AS A SIGNIFICANT
SHORT WAVE TROUGH DIGS FROM THE LEE OF THE CANADIAN ROCKIES INTO THE
UPPER GREAT LAKES REGION...WITHIN THE MAIN BELT OF THE POLAR
WESTERLIES. THE CLOSED LOW IS ULTIMATELY PROGGED TO EVOLVE INTO AN
OPEN SHORT WAVE TROUGH BEFORE MERGING INTO THE STRONGER WESTERLIES
ACROSS THE EASTERN CANADIAN PROVINCES...AS THE UPSTREAM IMPULSE
TURNS EAST OF THE UPPER GREAT LAKES SATURDAY NIGHT INTO EARLY
SUNDAY.
MODELS INDICATE THAT THE EVOLVING UPPER PATTERN WILL BE ACCOMPANIED
BY SIGNIFICANT SURFACE CYCLOGENESIS FROM LAKE HURON/GEORGIAN BAY
THROUGH EASTERN QUEBEC. AND...A TRAILING COLD FRONT IS PROGGED TO
ADVANCE THROUGH THE NORTHEASTERN STATES AND THE NORTHERN/MID
ATLANTIC SEABOARD. IN ADVANCE OF THE FRONT...AND IN THE WAKE OF A
RETREATING SURFACE RIDGE...STRONG DEEP LAYER SOUTHERLY FLOW IS
EXPECTED TO RESULT IN A FAIRLY SUBSTANTIAL MOISTURE RETURN...WITHIN
A NARROW TONGUE ACROSS THE DELMARVA PENINSULA INTO THE LOWER HUDSON
VALLEY BY EARLY SATURDAY.
..PARTS OF MID ATLANTIC STATES INTO SRN/WRN NEW ENGLAND...
FORECAST SOUNDINGS WITHIN AFOREMENTIONED NARROW PRE-FRONTAL MOIST
TONGUE ARE CHARACTERIZED BY POSITIVE BOUNDARY LAYER BUOYANCY /ALBEIT
VERY WEAK/ AND SIZABLE CLOCKWISE-CURVED LOW-LEVEL HODOGRAPHS BENEATH
A 40-50+ KT LOW-LEVEL JET BY MID DAY SATURDAY. JUST TO THE EAST OF
A 70-90 KT 500 MB JET CORE PROGGED TO SHIFT EAST OF THE UPPER OHIO
VALLEY/LOWER GREAT LAKES THROUGH NEW ENGLAND...THESE PARAMETERS WILL
PROVIDE A RISK FOR DAMAGING WINDS...PERHAPS A TORNADO OR TWO...IN
ASSOCIATION WITH CONVECTION DEVELOPING IN RESPONSE TO STRONG FORCING
ALONG/JUST AHEAD OF FRONT. HOWEVER...WITH COLD AIR ALOFT LAGGING TO
THE WEST OF THE SURFACE FRONT...WARM MID-LEVELS AND NEARLY SATURATED
PROFILES THROUGH MID/UPPER LEVELS COULD BE INHIBITIVE TO VIGOROUS
UPDRAFTS AND SEVERE POTENTIAL. MODELS ARE SUGGESTIVE THAT ANY
APPRECIABLE CONVECTIVE POTENTIAL WILL DIMINISH BY LATE SATURDAY
AFTERNOON OR EARLY EVENING...AS STRONGER MID-LEVEL FORCING FOR
UPWARD VERTICAL MOTION SHIFTS NORTHEAST OF REGION...FOLLOWED BY
VEERING WIND FIELDS/DRYING THERMODYNAMIC PROFILES.
.KERR.. 10/26/2007
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