[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 131737
SWODY2
SPC AC 131735

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1235 PM CDT TUE JUN 13 2006

VALID 141200Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE NRN ROCKIES TO NRN
PLAINS...

...SYNOPSIS...
STRONGLY AMPLIFIED BUT RELATIVELY PROGRESSIVE UPPER FLOW WILL
PERSIST ACROSS THE CONUS THROUGH MIDWEEK. AN IMPULSE ROUNDING THE
BASE OF THE ELONGATED WEST COAST TROUGH IS FORECAST TO PIVOT NEWD
AND PRODUCE MODERATE HEIGHT FALLS FROM THE NRN GREAT BASIN TO THE
NRN HIGH PLAINS INTO EARLY THURSDAY. MEANWHILE...UPPER RIDGE
CURRENTLY SITUATED ACROSS THESE AREAS WILL SHIFT EWD OVER THE PLAINS
STATES THROUGH THE PERIOD...AND EXTEND NWD INTO SCNTRL CANADA.

CIRCULATION ASSOCIATED WITH T.D. ALBERTO WILL BECOME INCREASINGLY
ABSORBED BY THE WLYS WHICH WILL ACT TO ACCELERATE THE REMAINS OF THE
TROPICAL SYSTEM NEWD ACROSS THE CAROLINAS EARLY IN THE PERIOD. THIS
WILL OCCUR AHEAD OF SHORT WAVE TROUGHING DEVELOPING SEWD ACROSS THE
OH VALLEY AND NORTHEAST AND CONTRIBUTING TO THE AMPLIFICATION OF THE
MEAN UPPER TROUGH COVERING THE ERN U.S.

...NRN ROCKIES/NRN PLAINS...
POTENT LARGE SCALE FORCING FOR ASCENT WILL ACCOMPANY THE IMPULSE
EJECTING NEWD FROM THE NRN GREAT BASIN EARLY IN THE DAY. THIS WILL
LIKELY SUSTAIN TSTMS ACROSS THE HIGHER TERRAIN THROUGH THE
MORNING...WITH THIS ACTIVITY SPREADING ACROSS THE CONTINENTAL DIVIDE
AND INTO CNTRL MT BY AFTERNOON. SHARPENING LEE-TROUGH WILL ENHANCE
UPSLOPE FLOW AND ACT TO FOCUS GREATER LOW LEVEL MOISTURE BENEATH THE
STRONG CAP FROM CNTRL MT/NRN WY EWD TO THE NRN HIGH PLAINS WHERE
STRONG DESTABILIZATION WILL TAKE PLACE. AS DIFFLUENT MID LEVEL FLOW
AND HEIGHT FALLS SPREAD ATOP THE CAPPED INSTABILITY AXIS THROUGH
LATE AFTERNOON...OROGRAPHIC AND DIABATIC FORCING WILL CONTRIBUTE TO
WEAKENING THE CAP SUFFICIENTLY FOR STORM INTENSIFICATION FROM NRN WY
ACROSS THE ERN HALF OF MT. DIRECTIONAL AND VERTICAL SPEED SHEAR
FORECAST ACROSS THE REGION WILL PROVE MORE THAN ADEQUATE FOR
SUPERCELLS WITH GOOD POTENTIAL FOR LARGE HAIL...HIGH WINDS...AND
PERHAPS A COUPLE TORNADOES.

LARGE SCALE FORCING AND FORECAST EVOLUTION OF CONVECTION STRONGLY
SUGGESTS THAT AN FORWARD PROPAGATING MCS OR TWO SHOULD DEVELOP EAST
INTO THE DAKOTAS THROUGH LATE EVENING. DEGREE OF POTENTIAL
INSTABILITY FEEDING INTO THIS ACTIVITY ON PLAINS LOW LEVEL JET
SHOULD MAINTAIN THE THREAT FOR SEVERE WEATHER EAST ACROSS THE NRN
PLAINS WELL INTO EARLY THURSDAY.

...CAROLINAS...
STRONG LOW LEVEL SHEAR WITHIN RIGHT FRONT QUADRANT OF ALBERTO
CIRCULATION WILL DEVELOP ACROSS THE ERN CAROLINAS DURING THE DAY.
RECENT FRONTAL PASSAGE ACROSS THE AREA HAS BROUGHT IN LOWER
DEWPOINTS/MORE STABLE AIR MASS. DESPITE STRONG MOISTURE ADVECTION
AHEAD OF THE TROPICAL SYSTEM...WIDESPREAD PRECIPITATION IN ADVANCE
OF THE LOW MAY KEEP DESTABILIZATION LIMITED GIVEN ANTECEDENT
RELATIVELY DRY BOUNDARY LAYER. WHILE AN ISOLATED/BRIEF TORNADO
CANNOT BE RULED OUT WITH SUCH A SYSTEM...POTENTIAL FOR WEAK
INSTABILITY PRECLUDES GREATER PROBABILITIES AT THIS TIME.

STRONGER INSTABILITY MAY...HOWEVER...DEVELOP IN THE WAKE OF
ALBERTO...ACROSS SRN NC/SC...AS SKIES CLEAR DURING THE AFTERNOON.
INCREASING WLY FLOW ACROSS THE REGION AHEAD OF OH VALLEY/SRN
APPALACHIANS SHORT WAVE TROUGH COULD PROMOTE SCATTERED ORGANIZED
STORMS OVER PARTS OF THE REGION BY LATE AFTERNOON/EARLY EVENING. A
SMALL CLUSTER OF SEVERE STORMS APPEARS POSSIBLE FROM SERN NC ACROSS
ERN SC DURING THIS TIME FRAME. IF THIS SIGNAL REMAINS COHERENT IN
LATER FORECASTS...SEVERE PROBABILITIES MAY NEED TO BE INCREASED OVER
PARTS OF THE AREA.

...MO VALLEY TO MIDWEST...
BAND OF SCATTERED CONVECTION MAY BE ONGOING FROM ERN SD...ACROSS
PARTS OF IA...AND INTO SRN WI/NRN IL...WITHIN WARM CONVEYOR ON THE
EDGE OF THE CAP EARLY WEDNESDAY. IT IS POSSIBLE THAT SOME OF THIS
ACTIVITY MAY ROOT INTO MARGINALLY UNSTABLE BOUNDARY LAYER FROM SRN
WI INTO NRN IL/NWRN IND DURING THE DAY AND INTO THE EVENING. THIS
ACTIVITY MIGHT BE FURTHER SUSTAINED BY STRONGER SHEAR/FORCING
ASSOCIATED WITH A SHORT WAVE DEVELOPING SEWD ACROSS THE REGION.
LATEST NAM-WRF INDICATES THE POTENTIAL FOR A FEW SEVERE STORMS WHILE
NAM-ETA IS NOT AS STRONG WITH THE MID LEVEL IMPULSE. GIVEN THESE
DIFFERENCES...WILL ONLY OUTLOOK LOW SEVERE PROBABILITIES AT THIS
TIME.

...MID ATLANTIC/NORTHEAST...
FORCING ASSOCIATED WITH OH VALLEY SHORT WAVE WILL CONTRIBUTE TO
SCATTERED TSTM DEVELOPMENT WITHIN WEAKLY UNSTABLE AIR MASS FROM
WV/NRN VA NEWD TO NEW ENGLAND DURING THE AFTERNOON. WHILE FORCING
AND SHEAR APPEAR SUPPORTIVE OF A FEW STORMS WITH MARGINALLY SEVERE
HAIL OR ISOLATED DAMAGING WINDS...LACK OF STRONGER DESTABILIZATION
SHOULD PREVENT THESE THREATS FROM BECOMING MORE WIDESPREAD.

..CARBIN.. 06/13/2006