[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 181737
SWODY2
SPC AC 181736

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1236 PM CDT SUN JUN 18 2006

VALID 191200Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS MONDAY FROM THE OH VALLEY TO
NEW ENGLAND...

...THERE IS A SLGT RISK OF SVR TSTMS MONDAY/MONDAY NIGHT ACROSS
PARTS OF THE NRN ROCKIES INTO THE NRN PLAINS AND PARTS OF THE MID MO
VALLEY...

...SYNOPSIS...
AMPLIFIED NRN STREAM WILL REMAIN PROGRESSIVE THROUGH THE DAY 2
PERIOD...WHILE A SUB-TROPICAL RIDGE BUILDS EWD THROUGH THE PLAINS
STATES.  ONE LARGE SCALE TROUGH DEVELOPING SEWD ACROSS THE UPPER MS
VALLEY AND ONTARIO DURING DAY 1 PERIOD WILL MOVE EWD THROUGH THE
GREAT LAKES/OH VALLEY TO NERN STATES BY 12Z TUESDAY.

UPSTREAM PACIFIC TROUGH IS PROGGED TO TRACK EWD ACROSS THE NRN
INTERMOUNTAIN WEST REACHING THE WRN DAKOTAS LATE DAY 2.  WEAKER
IMPULSES...WITHIN SRN FRINGE OF STRONGER SWLY MID LEVEL FLOW
EXPECTED TO EXTEND FROM THE GREAT BASIN TO NRN PLAINS...WILL TRACK
OVER THE CENTRAL HIGH PLAINS BY LATE MONDAY AFTERNOON.

...GREAT LAKES/OH VALLEY INTO THE NORTHEAST...
UPPER TROUGH JUST SOUTH OF MAIN BELT OF WESTERLIES IS PROGGED TO
WEAKEN AS IT SPREADS E TOWARD THE ERN SEABOARD MONDAY. HOWEVER...
STRONGER IMPULSE...WITHIN NRN EXTENT OF THIS TROUGH AND CURRENTLY
LOCATED OVER THE MID MS VALLEY...IS EXPECTED TO ACCELERATE NEWD FROM
THE UPPER OH VALLEY TO NRN NEW ENGLAND/ST LAWRENCE VALLEY.  30-40 KT
SWLY LOW-MID LEVEL FLOW WILL LIKELY ACCOMPANY THIS FEATURE ACROSS
THE NERN STATES.  SURFACE FRONT ASSOCIATED WITH LEAD TROUGH WILL
SPREAD EWD ACROSS NY/CENTRAL-SRN APPALACHIANS THROUGH MONDAY
AFTERNOON REACHING VT TO ERN PA/MD AND CENTRAL VA BY 20/00Z.

A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS MAY BE ONGOING ACROSS THE
LOWER GREAT LAKES/UPPER OH VALLEY TO ERN TN AT 12Z MONDAY ALONG THE
FRONT. SURFACE HEATING DOWNSTREAM OF THIS ACTIVITY IS EXPECTED TO
RESULT IN MODERATE INSTABILITY NEWD FROM CENTRAL PA BY EARLY MONDAY
AFTERNOON.  THUNDERSTORMS ARE EXPECTED TO INCREASE IN
COVERAGE/INTENSITY AS THE FRONT MOVES EWD INTO THE GREATER
INSTABILITY WITH LINEAR FORCING SUGGESTING A SQUALL LINE WILL BE
POSSIBLE WITH DAMAGING WINDS AND HAIL THE PRIMARY THREATS.  SEVERE
THREAT SHOULD SPREAD ENE INTO WRN/NRN NEW ENGLAND BEFORE WEAKENING
MONDAY NIGHT WITH A DECREASE IN CONVECTIVE INSTABILITY.

FARTHER WEST...SURFACE HEATING IS EXPECTED IN THE WAKE OF MORNING
ACTIVITY ACROSS THE UPPER OH VALLEY AND ALONG/E OF A SECOND SURFACE
FRONT ASSOCIATED WITH GREAT LAKES UPPER TROUGH.  THIS FRONT SHOULD
EXTEND FROM LOWER MI TO CENTRAL IL BY EARLY MONDAY AFTERNOON.  A MID
LEVEL IMPULSE TRACKING THROUGH BASE OF UPPER TROUGH WILL MOVE ACROSS
OH VALLEY MONDAY AFTERNOON/EVENING.  RESULTANT STEEPENING OF LAPSE
RATES DUE TO SURFACE HEATING AND ADVECTION OF COLD MID LEVEL
TEMPERATURES WITH IMPULSE WILL SUPPORT MODERATE INSTABILITY ACROSS
THE OH VALLEY. ASCENT AHEAD OF IMPULSE WILL SUPPORT THUNDERSTORMS
ALONG SECONDARY FRONT MONDAY AFTERNOON WITH ACTIVITY SPREADING EWD
THROUGH THE OH VALLEY... REACHING SWRN NY/WRN PA AND WV MONDAY
EVENING.  50 KT MID LEVEL JET ACCOMPANYING IMPULSE WILL RESULT IN
SUFFICIENT DEEP LAYER SHEAR FOR STORM ORGANIZATION WITH DAMAGING
WINDS/HAIL THE PRIMARY THREATS.

...NRN ROCKIES THROUGH NRN/CENTRAL PLAINS....
MOISTURE RETURN WITHIN UPSLOPE FLOW REGIME ALONG THE HIGH PLAINS IS
EXPECTED TO BE MARGINAL WITH LOWER 60S SURFACE DEWPOINTS POTENTIALLY
EXTENDING INTO WRN NEB/NWRN KS MONDAY AFTERNOON.  DESPITE THIS
LIMITING FACTOR...STEEPENING LAPSE RATES AND STRONG FORCING
SPREADING EWD AHEAD OF THE APPROACHING PACIFIC UPPER TROUGH COMBINED
WITH OROGRAPHIC ASCENT ARE EXPECTED TO GENERATE DEEP CONVECTION BY
MID-LATE MONDAY AFTERNOON OVER SW MT/WRN WY.  HAIL AND DAMAGING
WINDS WILL BE POSSIBLE WITH THIS INITIAL ACTIVITY.  WARM MID LEVEL
TEMPERATURES TO THE S OF THE UPPER TROUGH AND WITHIN SUB-TROPICAL
RIDGE ARE EXPECTED TO CAP THE PLAINS STATES INCLUDING ERN MT/WY
THROUGH MUCH OF THE DAY.  HOWEVER...LARGE DEWPOINT DEPRESSIONS WILL
RESULT IN INVERTED-V THERMODYNAMIC PROFILES ALONG THE NRN HIGH
PLAINS.  THIS COMBINED WITH STRENGTHENING WLY MID LEVEL WINDS /50
KT/ SUGGEST THE SEVERE THREAT COULD TRANSITION INTO A GREATER
DAMAGING WIND POTENTIAL AS THE PACIFIC FRONT SPREADS EWD THROUGH
MT/NRN WY.

FARTHER S ALONG THE LEE TROUGH...ISOLATED STRONG TO SEVERE STORMS
WILL BE POSSIBLE INTO WRN NEB AS STRONG SURFACE HEATING WEAKENS THE
CAP BY LATE MONDAY AFTERNOON.  DAMAGING WINDS AND LARGE HAIL WILL BE
POSSIBLE WITH THIS ACTIVITY.

LOW/MID-LEVEL WARM ADVECTION ON EDGE OF CAP WILL PROBABLY SUPPORT AN
EVOLVING CONVECTIVE CLUSTER ACROSS ND/SD AS MID-LEVEL JET NOSES INTO
THE NORTHERN PLAINS MONDAY NIGHT.  HAIL AND DAMAGING WINDS WILL BE
POSSIBLE WITH THIS OVERNIGHT COMPLEX.

OTHER STORMS...PRIMARILY WITH LARGE HAIL POTENTIAL...STILL APPEAR
POSSIBLE LATE MONDAY NIGHT AS LIFT STRENGTHENS ON EDGE OF STRONGER
CAPPING EAST OF THE MID MO VALLEY.

..PETERS.. 06/18/2006