[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 221703
SWODY2
SPC AC 221702

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1202 PM CDT SAT JUL 22 2006

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM CHESAPEAKE BAY INTO PARTS
OF THE CAROLINAS...

...SYNOPSIS...

ERN U.S. TROUGH IS FORECAST TO WEAKEN AS IT LIFTS NEWD IN RESPONSE
TO APPROACH OF UPSTREAM SHORT WAVE TROUGH MOVING THROUGH ONTARIO. 
IN THE W...SOME FLATTENING OF RIDGE WILL OCCUR ACROSS THE PACIFIC NW
INTO NRN ROCKIES WITH MID-LEVEL HIGH REMAINING ANCHORED OVER THE
GREAT BASIN.  IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH
WEAKENING TROUGH WILL DEVELOP NEWD FROM ME INTO THE CANADIAN
MARITIMES WITH TRAILING COLD FRONT PUSHING OFF THE NEW ENGLAND AND
MIDDLE ATLANTIC COASTS.  FARTHER TO THE S...FRONT WILL BE SLOWER TO
PUSH EWD FROM CHESAPEAKE BAY SWD THROUGH THE PIEDMONT AND COASTAL
PLAIN. A SECONDARY COLD FRONT WILL PUSH SWD INTO THE N-CNTRL TIER
OF STATES IN ASSOCIATION WITH ONTARIO IMPULSE.

...CHESAPEAKE BAY INTO THE CAROLINAS...

AS MENTIONED ABOVE...SURFACE FRONT WILL BE SLOW TO SHIFT EWD THROUGH
THE PERIOD OWING TO WEAKENING LARGE-SCALE FORCING AND INCREASINGLY
PARALLEL ORIENTATION OF BOUNDARY TO MID AND UPPER-LEVEL FLOW FIELDS.
PRE-FRONTAL AIR MASS WILL REMAIN QUITE MOIST WITH DEWPOINTS IN THE
UPPER 60S TO LOW/MID 70S...AND WHEN COUPLED WITH DIABATIC
HEATING...BOUNDARY LAYER WILL BECOME MODERATELY UNSTABLE BY
AFTERNOON WITH MLCAPES OF 1000-2500 J/KG.

NEUTRAL TO SLIGHT HEIGHT RISES DURING TIME OF PEAK HEATING WOULD
SUGGEST THAT LARGE-SCALE FORCING WILL REMAIN QUITE NEGLIGIBLE...AND
THAT TSTM DEVELOPMENT WILL LIKELY BE DRIVEN BY A WEAK CAP AND
LOW-LEVEL CONVERGENCE ALONG FRONTAL ZONE.  DESPITE NEAR MOIST
ADIABATIC MID-LEVEL LAPSE RATES...THE PRESENCE OF MODESTLY STRONG
/30-35 KT/ MID-LEVEL FLOW...THE MODERATE INSTABILITY AND RELATIVELY
STEEP LOW-LEVEL LAPSE RATES...SCATTERED SEVERE STORMS WILL BE
POSSIBLE WITH THE PRIMARY SEVERE WEATHER THREAT BEING LOCALLY
DAMAGING WINDS.  STORMS SHOULD TEND TO WEAKEN BY MID TO LATE EVENING
AS BOUNDARY LAYER SLOWLY STABILIZES.

...UPPER MS VALLEY INTO NRN HIGH PLAINS...

BOUNDARY LAYER MOISTURE WILL REMAIN QUITE LIMITED AHEAD OF COLD
FRONT MOVING SWD OUT OF CANADA WITH DEWPOINTS IN THE 40S TO PERHAPS
LOW/MID 50S.  HOWEVER...FORECAST SOUNDINGS INDICATE THE PRESENCE OF
RELATIVELY STEEP LOW TO MID-LEVEL LAPSE RATES WHICH WILL LARGELY
CONTRIBUTE TO MLCAPES OF 500-1000 J/KG.  STORMS WILL LIKELY DEVELOP
NEAR OR JUST N OF THE INTERNATIONAL BORDER DURING THE LATE AFTERNOON
OR EARLY EVENING HOURS ALONG OR SLIGHTLY BEHIND SURFACE FRONT. 
ACTIVITY SHOULD THEN MOVE/DEVELOP SWD INTO NRN MN...ND AND MT SUNDAY
EVENING AND NIGHT WITH A THREAT OF ISOLATED SEVERE HAIL AND GUSTY
WINDS.

...SRN ROCKIES INTO AZ DESERTS...

ERN PERIPHERY OF WRN U.S. HIGH IS FORECAST TO BE CONVECTIVELY ACTIVE
SUNDAY AFTERNOON AND EVENING OWING STRONG HEATING ALONG THE ELEVATED
TERRAIN AND THE SUBTLE INFLUENCE OF WEAK IMPULSES EMBEDDED IN
LARGER-SCALE CIRCULATION.  STRONG BOUNDARY LAYER HEATING/MIXING WILL
RESULT IN A DEEP SUB-CLOUD LAYER WITH SBCAPES INCREASING TO 500-800
J/KG...WHICH WILL BE SUPPORTIVE OF ISOLATED SEVERE STORMS CAPABLE OF
LOCALLY DAMAGING WINDS.  A POTENTIALLY GREATER THREAT OF MORE
ORGANIZED STORMS CAPABLE OF DAMAGING WINDS WILL EXIST FROM ERN AZ
INTO THE LOWER DESERTS WHERE DEEPER 20-30 KT NELY/ELY SHEAR WILL
FAVOR COLD POOL ORGANIZATION WITH ANY STORM CLUSTERS MOVING OFF THE
MOGOLLON RIM.

..MEAD.. 07/22/2006