[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 231722
SWODY2
SPC AC 231721

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1221 PM CDT SUN JUL 23 2006

VALID 241200Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE UPPER
GREAT LAKES WWD INTO ERN SD...

...SYNOPSIS...

FLATTENING OF SWRN U.S. RIDGE IS FORECAST DURING THE DAY TWO PERIOD
OWING TO THE TRANSLATION OF WEAK IMPULSES FROM THE PACIFIC NW AND
NRN ROCKIES INTO THE NRN PLAINS.  IN THE NE...HEIGHTS WILL REBOUND
IN WAKE OF SHORT WAVE TROUGH LIFTING NEWD INTO THE CANADIAN
MARITIMES.  IN THE LOW-LEVELS...A COLD FRONT ASSOCIATED WITH A SHORT
WAVE TROUGH MOVING THROUGH ONTARIO WILL PUSH SEWD INTO THE UPPER
GREAT LAKES WITH THIS BOUNDARY EXTENDING WWD TO DEVELOPING LOW
PRESSURE OVER SD.  MEANWHILE IN THE SE...REMNANT BOUNDARY FROM THE
NC COAST INTO THE NWRN GULF OF MEXICO WILL WEAKEN THROUGH THE
PERIOD.

...UPPER GREAT LAKES INTO NRN PLAINS...

CLUSTERS OF ELEVATED TSTMS ARE EXPECTED TO BE ONGOING MONDAY MORNING
OVER PARTS OF WI INTO THE UP MI WITHIN LOW-LEVEL WAA REGIME
ASSOCIATED WITH SHORT WAVE TROUGH MOVING THROUGH ONTARIO.  WHILE
SOME HAIL WILL BE POSSIBLE WITH THESE STORMS THROUGH THE MORNING
HOURS...THIS ACTIVITY SHOULD GENERALLY MOVE EWD INTO SWRN ONTARIO BY
AFTERNOON.  ADDITIONAL...DIURNAL STORM DEVELOPMENT WILL BE POSSIBLE
BY AFTERNOON ALONG COLD FRONT PUSHING SEWD INTO REGION FROM LOWER MI
WWD THROUGH WI...CNTRL/SRN MN AND ERN SD.

LATEST MODEL GUIDANCE SUGGESTS THAT MODEST BOUNDARY LAYER MOISTURE
/DEWPOINTS OF 55-65 F...DECREASING TO GENERALLY 50S WWD OVER SD/
COUPLED WITH STEEP LOW TO MID-LEVEL LAPSE RATES WILL CONTRIBUTE TO
MODERATE INSTABILITY BY AFTERNOON WITH MLCAPES OF 1000-2000 J/KG.
THE STRONGEST VERTICAL SHEAR IS FORECAST TO EXIST IN CLOSER
PROXIMITY TO ONTARIO IMPULSE N OF THE INTERNATIONAL BORDER...AND TO
THE W OVER WRN/CNTRL SD WITH GENERALLY 25-35 KTS OF DEEP-LAYER SHEAR
EXPECTED ACROSS SLIGHT RISK PORTION OF FRONTAL ZONE.

SURFACE-BASED TSTMS WILL BECOME INCREASINGLY LIKELY BY AFTERNOON
ALONG FRONT OWING TO GLANCING INFLUENCE OF ONTARIO SHORT WAVE TROUGH
AND INCREASED LARGE-SCALE FORCING ASSOCIATED WITH WEAKER UPSTREAM
IMPULSE MOVING THROUGH THE NRN PLAINS. STORMS SHOULD REMAIN LARGELY
MULTICELLULAR FROM LOWER MI WWD INTO MN WITH A THREAT OF LARGE HAIL
AND DAMAGING WINDS.  DESPITE WEAKENING INSTABILITY WITH WWD EXTENT
INTO SD...POTENTIAL WILL EXIST FOR A COUPLE OF HIGH-BASED MARGINAL
SUPERCELLS...SUPPORTED BY THE STEEP LAPSE RATES AND AROUND 35 KTS OF
DEEP-LAYER SHEAR.  THESE STORMS WILL ALSO BE CAPABLE OF LOCALLY HIGH
WINDS AND HAIL.

...NRN HIGH PLAINS...

A FEW HIGH-BASED STRONG TO MARGINALLY SEVERE STORMS WILL BE POSSIBLE
MONDAY AFTERNOON AND EVENING ALONG WRN EXTENSION OF FRONTAL BOUNDARY
OVER MT.  LOW-LEVEL MOISTURE WILL REMAIN LIMITED...THOUGH THE
PRESENCE OF STEEP LAPSE RATES WILL SUPPORT MARGINAL INSTABILITY. 
FORECAST SOUNDINGS INDICATE THAT VERTICAL SHEAR WILL BE SUFFICIENT
FOR SOME STORM ORGANIZATION WITH A THREAT OF ISOLATED STRONG
WINDS/SEVERE HAIL.

...CNTRL ROCKIES TOWARD THE LOWER CO VALLEY...

DIURNAL TSTMS ARE EXPECTED TO DEVELOP ALONG THE HIGHER TERRAIN
AROUND PERIPHERY OF FLATTENING MID-LEVEL RIDGE MONDAY AFTERNOON AND
EVENING.  A SHORT WAVE TROUGH MOVING SWD THROUGH CO WILL LIKELY
FOCUS A MORE CONCENTRATED CLUSTER OF STORMS FROM S-CNTRL CO INTO
CNTRL NM...WITH MORE WIDELY SCATTERED DEVELOPMENT ANTICIPATED ALONG
OROGRAPHICALLY FAVORED AREAS.  DEEP BOUNDARY LAYER MIXING WILL
RESULT IN THE DEVELOPMENT OF STEEP LOW-LEVEL LAPSE RATES AND STRONG
EVAPORATIONAL COOLING POTENTIAL IN THE SUB-CLOUD LAYER WITH LOCALLY
DAMAGING WINDS POSSIBLE WITH THE STRONGEST STORMS.

...SRN ATLANTIC COAST...

RICH BOUNDARY LAYER MOISTURE COUPLED WITH DAYTIME HEATING ARE
EXPECTED TO CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS MONDAY TO
THE S OF WEAKENING FRONTAL ZONE WITH MLCAPES INCREASING TO 1500-2500
J/KG.  LITTLE OR NO CONVECTIVE INHIBITION SHOULD ALLOW TSTMS TO
BECOME FAIRLY WIDESPREAD ACROSS THE REGION BY PEAK HEATING WITH THE
POTENTIAL FOR ISOLATED...SEVERE WET MICROBURSTS.

..MEAD.. 07/23/2006