SPC AC 170545
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1145 PM CST TUE NOV 16 2010
VALID 171200Z - 181200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A DEAMPLIFYING/INCREASINGLY PROGRESSIVE LARGE SCALE UPPER FLOW
PATTERN WILL DEVELOP OVER THE CONUS THROUGH THE PERIOD. A
CONSIDERABLE NEGATIVE TILT UPPER TROUGH WILL CONTINUE TO ACCELERATE
NORTHEASTWARD OVER THE NORTHEAST/NEW ENGLAND STATES TODAY. IN ITS
WAKE...A SOUTHERN SPLIT FAST MOVING SHORTWAVE TROUGH WILL CROSS THE
SOUTHERN PLAINS/ARKLATEX VICINITY THROUGH THIS EVENING...ALL AHEAD
OF ANOTHER UPPER TROUGH/COLD FRONT REACHING THE PACIFIC NORTHWEST.
...NORTHEAST STATES/NEW ENGLAND...
IN ASSOCIATION WITH THE AFOREMENTIONED UPPER TROUGH/STRONG POLAR
JET...A SURFACE LOW WILL CONTINUE TO STEADILY SPREAD NORTHEASTWARD
OVER THE LOWER GREAT LAKES REGION INTO SOUTHEAST ONTARIO/SOUTHERN
QUEBEC...WHILE A COLD FRONT CONTINUES TO STEADILY RACE OFF THE
ATLANTIC COAST...SAVE A GRADUALLY OCCLUDING PORTION OF THE FRONT
ACROSS NEW ENGLAND.
WHILE MUCH OF THE EARLY MORNING CONVECTION PUSHES OFFSHORE ATTENDANT
TO THE COLD FRONT...CURRENT THINKING IS THAT A STRONGLY FORCED
LOW-TOPPED CONVECTIVE LINE WILL BE ONGOING/RACING NORTHEASTWARD
ALONG/AHEAD OF THE ADVANCING COLD FRONT...PROBABLY ACROSS PORTIONS
OF NJ/EASTERN NY INTO WESTERN NEW ENGLAND THROUGH EARLY/MID MORNING.
APPRECIABLE DESTABILIZATION IS UNLIKELY TO OCCUR...WITH SBCAPE
LIKELY LIMITED TO ONLY A FEW HUNDRED J/KG. HOWEVER...ROBUST EARLY
DAY MOISTURE TRANSPORT JUST ABOVE THE SURFACE...STEEPENING LAPSE
RATES ALOFT...COUPLED WITH AN APPRECIABLE MAGNITUDE OF FORCING AND
FLOW ALOFT /ACCENTUATED BY 50 KT FLOW AROUND 1-2 KM/...WILL YIELD A
SCENARIO CONDUCIVE FOR CONVECTIVELY ENHANCED/AT LEAST NEAR-SEVERE
WIND GUSTS. WIND DAMAGE WILL BE MOST PROBABLE WITH ANY SMALL BOWING
SEGMENTS AND/OR UPDRAFTS VIGOROUS ENOUGH TO PRODUCE CG
LIGHTNING...WITHIN WHAT IS EXPECTED TO BE A DOMINANT
QUASI-LINEAR/LOW-TOPPED CONVECTIVE MODE. THE OVERALL SEVERE THREAT
SHOULD GRADUALLY WANE/SHIFT OFFSHORE THROUGH EARLY/MID AFTERNOON.
...PACIFIC NORTHWEST...
INLAND SPREADING EXIT REGION OF A STRONG UPPER JET/ASSOCIATED COLD
FRONT WILL SUPPORT INCREASING CONVECTION THIS AFTERNOON/EVENING.
MOST OF THE SHOWERY CONVECTION WILL BE VOID OF CG LIGHTNING...BUT
ISOLATED TSTMS WILL BE POSSIBLE MAINLY FOR WA COASTAL AREAS/OFFSHORE
WATERS ALONG/BEHIND THE INLAND ADVANCING FRONT.
...OZARKS/ARKLATEX...
AS A SHORTWAVE TROUGH/SPEED MAX STEADILY PROGRESSES EASTWARD OVER
THE ARKLATEX REGION THIS AFTERNOON/EVENING...MOISTURE
RETURN/RESULTANT DESTABILIZATION WILL BE QUITE MEAGER AHEAD OF AN
ADVANCING SURFACE LOW/COLD FRONT. BUT...POTENTIAL FOR LOW-TOPPED
TSTMS IS NON-ZERO /ESPECIALLY PER THE 00Z NAM/ LATE THIS AFTERNOON
AND EVENING ACROSS AR...AND PERHAPS ADJACENT PORTIONS OF NORTHERN
LA/WESTERN MS/SOUTHERN MO. HOWEVER...CURRENT EXPECTATIONS ARE FOR A
RATHER ISOLATED TSTM COVERAGE AND THE OVERALL PROBABILITY APPEARS TO
BE SUB 10 PERCENT.
..GUYER/HURLBUT.. 11/17/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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