[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 131642
SWODY1
SPC AC 131640

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1040 AM CST MON MAR 13 2006

VALID 131630Z - 141200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER SERN LOWER MI..ERN
INDIANA..CENTRAL/ERN KY..OH..WRN NY..WRN PA..AND WRN WV....

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
EAST OF THE MS VALLEY INTO THE TN VALLEY AND NEWD INTO THE MID
ATLANTIC REGION AND ERN NY....

...SYNOPSIS...
VIGOROUS LOW ALOFT OVER THE UPPER MS VALLEY REGION IS EXPECTED TO
LIFT ENEWD ACROSS THE UPPER LAKES TODAY REACHING ERN ONTARIO
TONIGHT...AS 120 KT MID LEVEL JET STREAK ROTATES FROM THE MIDDLE MS
VALLEY ACROSS THE OH VALLEY AND LOWER GREAT LAKES.  DEEP SURFACE LOW
OVER SRN WI IS FORECAST TO CONTINUE INTENSIFYING AS IT LIFTS NEWD
TOWARD ERN LAKE SUPR/NRN LAKE MI THIS AFTERNOON TO NEAR THE
ONTARIO/QUEBEC BORDER AREA BY THE END OF THE PERIOD. A COLD FRONT
EXTENDING SWD FROM THE LOW WILL MOVE EWD REACHING WRN LAKE ERIE/N
CENTRAL KY/NRN MS/SWRN LA LINE LATE THIS AFTERNOON...AND NEW
ENGLAND/DELMARVA/UPSTATE SC/NWRN FL LINE BY 14/12Z...AS THE NRN PART
OF THE FRONT SURGES EWD MORE RAPIDLY.  A WARM FRONT FROM THE
DELMARVA INTO WRN NY WILL MOVE SLOWLY NWD.

...GREAT LAKES INTO OH VALLEY AND MID ATLANTIC STATES...
MORNING CONVECTION IS CONTINUING FROM NY INTO SRN LOWER MI AND SWWD
INTO THE MID SOUTH IN ADVANCE OF AFOREMENTIONED COLD FRONT.  THIS
HAS SPREAD CLOUDS ACROSS MUCH OF THE AREA FROM THE LOWER GREAT LAKES
INTO THE OH VALLEY...WHICH WILL LIKELY INHIBIT STRONG DIURNAL
HEATING ACROSS PARTS OF THIS REGION WEST OF THE APPALACHIANS. 
SURFACE DEW POINTS ARE EXPECTED TO BE IN THE 55-60F RANGE ACROSS
MUCH OF THE REGION...WITH A NARROW AXIS OF LOW 60S DEW POINTS MAY BE
LOCATED IMMEDIATELY AHEAD OF THE ADVANCING COLD FRONT. INSTABILITY
IS EXPECTED TO BE MODEST AT BEST THIS AFTERNOON WITH MLCAPE VALUES
OF 500-1000 J/KG...ALTHOUGH LOCALLY GREATER INSTABILITY MAY DEVELOP
ALONG/IMMEDIATELY AHEAD OF THE COLD FRONT WHERE A NARROW ZONE OF
CLEAR SKIES AND ENHANCED INSOLATION ARE LOCATED.

WINDS ALOFT ARE VERY STRONG ACROSS THE REGION WITH 12Z RAOBS AND
CURRENT VWPS INDICATING 50 KT FLOW AS LOW AS 500-1000 M AGL. 
VERTICAL SHEAR WILL REMAIN VERY STRONG WITH 50-60 KT IN THE LOWEST 6
KM WHICH WILL ENHANCE STORM ORGANIZATION INCLUDING POTENTIAL FOR
SUPERCELLS.  VERY FAVORABLE LOW LEVEL SHEAR AND CLOCKWISE TURNING
LOW LEVEL HODOGRAPHS WILL ALSO BE SUPPORTIVE OF A FEW TORNADOES...
ESPECIALLY FOR ANY DISCRETE SUPERCELLS THAT MAY DEVELOP.

CONVECTIVE EVOLUTION IS EXPECTED TO BE COMPLEX THIS AFTERNOON...WITH
POTENTIAL FOR MULTIPLE BANDS OF STRONG/SEVERE STORMS MOVING EWD
ACROSS THE WARM SECTOR IN ADVANCE OF THE COLD FRONT.  IN
ADDITION...MORNING MODEL GUIDANCE FROM RUC/ETA/AND PARALLEL NAM-WRF
ALL INDICATE REDEVELOPMENT OF STORMS ALONG THE COLD FRONT FROM SRN
LOWER MI SSWWD INTO THE MID SOUTH DURING THE MID AFTERNOON WHICH
WILL ACCELERATE EWD AS THE FRONT SURGES EWD THROUGH TONIGHT.  THERE
IS POTENTIAL FOR WIDESPREAD DAMAGING WINDS TO OCCUR AS THE MULTIPLE
BANDS MOVE RAPIDLY EWD/NEWD ACROSS THE LOWER GREAT LAKES AND OH
VALLEY REGION...IN ADDITION TO POSSIBLE TORNADOES AND HAIL.  GIVEN
THE STRONG DYNAMIC FORCING AND PROGRESSIVE PATTERN...STRONG/SEVERE
CONVECTION MAY SPREAD EWD INTO THE MID ATLANTIC REGION DURING THE
OVERNIGHT HOURS WITH PRIMARY THREAT OF A LOW-TOPPED CONVECTION
CAPABLE OF PRODUCING DAMAGING WIND GUSTS.

...TN VALLEY/LOWER MS VALLEY INTO SERN STATES...
ALTHOUGH PRIMARY FORCING FOR LARGE SCALE ASCENT WILL MOVE FARTHER
NORTH...THREAT FOR THUNDERSTORM DEVELOPMENT IS EXPECTED TO INCREASE
THIS AFTERNOON AS THE COLD FRONT MOVES EWD FROM THE LOWER MS VALLEY
TOWARD THE SRN APPALACHIANS.  ALTHOUGH MID LEVEL TEMPERATURES ARE
RELATIVELY WARM...SURFACE DEW POINTS IN THE MID 60S COUPLED WITH
STRONG DEEP LAYER SHEAR OF 50 KT OR GREATER WILL PROVIDE AN
ENVIRONMENT SUPPORTIVE OF STRONG/SEVERE STORMS...INCLUDING ISOLATED
SUPERCELLS...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS.

..WEISS/GUYER.. 03/13/2006