[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 091257
SWODY1
SPC AC 091256

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0756 AM CDT SAT SEP 09 2006

VALID 091300Z - 101200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
HIGH AMPLITUDE FLOW PATTERN IS FORECAST TO PERSIST TODAY WITH
PRIMARY BAND OF WESTERLIES CURVING FROM BRITISH COLUMBIA INTO
CENTRAL CANADA THEN SEWD ACROSS THE UPPER GREAT LAKES/ST LAWRENCE
VALLEY.  A SHORT WAVE TROUGH WILL MOVE EWD FROM THE NRN GREAT LAKES
ACROSS NEW ENGLAND...FORCING A STRONG SURFACE COLD FRONT SEWD ACROSS
THE NERN STATES AND THE OH VALLEY.  THIS BOUNDARY WILL EXTEND WWD AS
A QUASI-STATIONARY FRONT INTO THE CENTRAL PLAINS.

IN THE WEST...A BROAD UPPER TROUGH WITH MULTIPLE VORTICITY MAXIMA
ACROSS THE GREAT BASIN/CENTRAL ROCKIES WILL PROGRESS EWD INTO
CENTRAL PLAINS.  SURFACE LOW PRESSURE DEVELOPING OVER SERN CO WILL
MOVE SLOWLY EWD INTO KS BY THE END OF THE PERIOD.  A DRY LINE IS
EXPECTED TO DEVELOP SWD FROM THE LOW THIS AFTERNOON NEAR THE TX/NM
BORDER.

...NEW ENGLAND INTO OH...
CONVECTION ALONG/AHEAD OF THE ADVANCING COLD FRONT HAS BEEN SLOWLY
INCREASING THIS MORNING FROM SRN LAKE ERIE INTO WRN PA...AND
ADDITIONAL THUNDERSTORMS ARE EXPECTED TO DEVELOP NEWD ALONG THE
FRONT INTO NRN NEW ENGLAND LATER THIS MORNING AND EARLY AFTERNOON. 
THE DEGREE OF INSTABILITY AHEAD OF THE FRONT IS EXPECTED TO BE
TEMPERED BY MODEST LOW LEVEL MOISTURE /SURFACE DEW POINTS GENERALLY
55-60 F/ AND GENERALLY WEAK MID LEVEL LAPSE RATES WHICH WILL INHIBIT
HEATING/DESTABILIZATION...WITH MAXIMUM MLCAPE OF 1000-1200 J/KG IN A
RELATIVELY NARROW AXIS AHEAD OF THE FRONT.  MODERATE WESTERLY WINDS
ALOFT WITH 30-40 KT 500 MB FLOW OVER NEW ENGLAND AND NY WILL
CONTRIBUTE TO SUFFICIENT SHEAR TO AID STORM ORGANIZATION.  WEAKER
WINDS ALOFT/VERTICAL SHEAR IS FORECAST SWWD ALONG THE FRONT INTO THE
OH VALLEY.  ISOLATED STRONG/SEVERE STORMS ARE POSSIBLE FROM LATER
THIS MORNING THROUGH THE AFTERNOON WITH MORE INTENSE CELLS CAPABLE
OF PRODUCING MARGINALLY SEVERE HAIL AND LOCALLY STRONG WIND GUSTS. 
THUNDERSTORM ACTIVITY IS EXPECTED TO DIMINISH BY LATE THIS AFTERNOON
OR EVENING AS THE FRONT GRADUALLY MOVES INTO A LESS FAVORABLE
ENVIRONMENT.

...CENTRAL PLAINS/SRN HIGH PLAINS...
LARGE SCALE ASCENT IN ADVANCE OF THE CENTRAL ROCKIES UPPER TROUGH
COUPLED WITH LOW LEVEL WARM ADVECTION IS RESULTING IN WIDESPREAD
CONVECTION FROM NERN CO INTO KS.  THE EXTENSIVE CLOUD COVER AND
PRECIPITATION IS EXPECTED TO INHIBIT DIURNAL HEATING TODAY AND LIMIT
MLCAPE TO 500-1000 J/KG.  GREATER HEATING IS EXPECTED TO OCCUR SWD
ACROSS PARTS OF WRN TX AS MID/UPPER LEVEL DRYING OVERSPREADS THE SRN
HIGH PLAINS FROM THE WEST.  SURFACE DEW POINTS OF 55-60F AND
TEMPERATURES WARMING GENERALLY INTO THE 80S WILL CREATE MLCAPE
AROUND 1000 J/KG THIS AFTERNOON.

VERTICAL WIND PROFILES ARE EXPECTED TO EXHIBIT STRONG DIRECTIONAL
SHEAR AS 20 KT SLY/SELY LOW LEVEL WINDS VEER TO 25-30 KT WNWLY WINDS
IN THE MID LEVELS...RESULTING IN 30-35 KT DEEP LAYER SHEAR ACROSS
THE REGION.

NEW CONVECTION MAY DEVELOP SWD ALONG THE DRYLINE THIS AFTERNOON...AS
WELL AS OVER WRN KS IN THE WAKE OF CURRENT CONVECTION IN THAT AREA. 
ALTHOUGH INSTABILITY WILL GENERALLY BE WEAK...SUFFICIENT VERTICAL
SHEAR SUGGESTS POTENTIAL FOR ISOLATED SEVERE STORMS TO
DEVELOP...WITH ACTIVITY SPREADING SLOWLY EWD TOWARD CENTRAL KS AND
POSSIBLY INTO WRN OK TONIGHT.

...NRN AZ/SRN UT...
WIDELY SCATTERED STRONG THUNDERSTORMS ARE CONTINUING ACROSS NWRN AZ
AND EXTREME SWRN UT IN ASSOCIATION WITH A VORTICITY MAX MOVING EWD
ACROSS EXTREME SRN NV. CURRENT ACTIVITY IS LOCATED WITHIN AXIS OF
HIGHER PRECIPITABLE WATER/INSTABILITY ACROSS NWRN AZ...WITH MOISTURE
DECREASING EWD ACROSS NRN AZ BASED ON GPS WATER VAPOR SENSORS. 
HOWEVER...PERSISTENT LARGE SCALE ASCENT IS EXPECTED TO RESULT IN
DEEP LAYER MOISTENING AHEAD OF THE VORTICITY MAX WITH CONTINUED
POTENTIAL FOR ISOLATED STRONG/SEVERE STORMS TO DEVELOP EWD TOWARD
THE FOUR CORNERS REGION THROUGH THIS EVENING.

..WEISS/GUYER.. 09/09/2006