[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 241712
SWODY2
SPC AC 241711

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1211 PM CDT MON JUL 24 2006

VALID 251200Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS DURING THE AFTERNOON OVER
EXTREME NRN MAINE....

...SYNOPSIS...
MID/UPPER LEVEL RIDGE WILL CONTINUE TO DOMINATE THE SOUTHWEST
QUARTER OF THE U.S.  FIRST MID/UPPER LEVEL SHORTWAVE TROUGH NOW OVER
ONTARIO IS FORECAST TO MOVE EWD INTO QUEBEC THEN LIFT NNEWD SKIRTING
WRN AND NRN EDGES OF MAINE TUESDAY AFTERNOON.  SECOND SHORTWAVE
TROUGH NOW OVER WRN SASKATCHEWAN IS EXPECTED TO MOVE ACROSS THE NRN
PLAINS AND UPPER MIDWEST DURING THE SECOND HALF OF THE PERIOD. 
FINALLY...MID/UPPER LEVEL TROUGH OVER NERN SECTIONS OF MEXICO IS
PROGGED TO INTENSIFY SLIGHTLY AND BECOME A CLOSED LOW OVER SOUTH
CENTRAL TEXAS BY THE END OF THE PERIOD.

...NRN PARTS OF MAINE...

ANALYSIS OF NAM...GFS AND NMM-WRF MODELS REVEAL MORE NEGATIVES THAN
POSITIVES FOR SEVERE POTENTIAL ACROSS THIS AREA.  THE SHORT RANGE
ENSEMBLE SEEMS TO BE THE SOLUTION THAT IS A LITTLE MORE AGGRESSIVE
DETAILING A 30 PERCENT PROBABILITY FOR SUPERCELLS AS IT BANKS ON THE
FAVORABLE SHEAR PROFILES IN THE FORECAST SOUNDINGS.  GIVEN THAT THE
INDIVIDUAL MODELS ARE TAKING THE SHORTWAVE TROUGH INTO THE ST.
LAWRENCE RIVER VALLEY IN SRN QUEBEC THEN LIFTING IT NNEWD DURING THE
AFTERNOON...PLUS FORECAST SOUNDINGS ARE INDICATING PERSISTENT CLOUD
COVER AS WELL AS LIMITED INSTABILITY /MLCAPE MAXING OUT AT 900 J/KG/
AND MOIST ADIABATIC LAPSE RATES OF 6C/KM...SEEMS THAT THE SEVERE
POTENTIAL COULD BE MARGINAL AT BEST.  COLD FRONTAL BOUNDARY
ACCOMPANYING THE MID/UPPER LEVEL TROUGH LOOKS TO BECOME
QUASISTATIONARY JUST WEST OF MAINE LEAVING A WEAKENING LINE OF
THUNDERSTORMS TO MOVE OVER THE REGION TOMORROW.

IF THERE IS ANY PROBABILITY FOR SEVERE...IT WILL BE STRONG WINDS
OVER THE EXTREME NWRN AND NRN MAINE WHERE BEST DYNAMICS WILL BRUSH
BY THE AREA.

...UPPER MIDWEST/WRN GREAT LAKES REGION...

SECOND MID/UPPER LEVEL TROUGH WILL DROP SEWD INTO THE NRN PLAINS AND
UPPER MIDWEST REGION DURING THE LATTER HALF OF THE PERIOD.  THIS
WILL BE ACCOMPANIED BY WEAK FRONTAL BOUNDARY/SURFACE TROUGH THAT
WILL EXTEND FROM N CENTRAL MN SWWD INTO SWRN SD BY 12Z WEDNESDAY. 
MODELS DEPICT AREA OF SCATTERED THUNDERSTORMS WILL DEVELOP ALONG THE
SURFACE TROUGH EARLY IN THE PERIOD THROUGH EARLY EVENING...GIVING
WAY TO CLUSTER OF STORMS/MCS OVER WI/IA TUE NIGHT AND WED MORNING. 
STEEP LOW LEVEL LAPSE RATES JUST ABOVE 7.5C/KM INDICATES THAT SOME
OF THE STORMS COULD PRODUCE STRONG DOWNBURSTS WITH PROBABILITIES
DIMINISHING AFTER SUNSET.

...SOUTHWESTERN U.S....

PERSISTENCE INDICATES THAT SCATTERED STRONG THUNDERSTORMS COULD
OCCUR ONCE AGAIN ACROSS THE REGION.  ELY MID LEVEL FLOW WILL
CONTINUE ACROSS AZ AND PARTS OF NM WITH VERY STEEP LAPSE RATES BELOW
600 MB.  THIS ALONG WITH VERY HIGH DCAPE VALUES OVER 1000 J/KG
INDICATES THE THREAT FOR STRONG DOWNBURSTS WITH SCATTERED
AFTERNOON/EVENING THUNDERSTORMS.

...SOUTH CENTRAL TEXAS EWD INTO LOWER MS VALLEY...

MID/UPPER LEVEL LOW IS FORECAST TO DEVELOP OVER S CENTRAL TX DURING
THE PERIOD.  AIR MASS WILL REMAIN VERY WARM AND MOIST WITH  MOIST
ADIABATIC LAPSE RATES AND LIMITED INSTABILITY WITH MOST UNSTABLE
CAPES BETWEEN 500 AND 800 J/KG.  SHEAR PROFILES INCREASE ACROSS S
CENTRAL TX AS LOW DEVELOPS INDICATING THE POSSIBILITY OF ISOLATED
SUPERCELLS LATE IN THE PERIOD.

..MCCARTHY.. 07/24/2006