[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 220609
SWODY1
SPC AC 220607

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0107 AM CDT SAT APR 22 2006

VALID 221200Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN VA AND THE CAROLINAS
TO FL...

...SYNOPSIS...
HIGHLY AMPLIFIED MULTI-STREAM UPPER FLOW WILL PERSIST ACROSS NORTH
AMERICA THROUGH THE WEEKEND WITH A HIGH PLAINS UPPER RIDGE AXIS
SEPARATING CLOSED LOWS OVER THE SOUTHWEST AND GREAT LAKES. A SRN
BRANCH SHORT WAVE TROUGH UNDERCUTTING THE GREAT LAKES LOW WILL
CONTINUE TO DRIVE A DEEP LAYER FRONTAL ZONE EWD ACROSS THE ATLANTIC
COAST STATES FROM FL TO NJ. IN THE WAKE OF THIS SYSTEM... LOW LEVEL
SLY FLOW WILL GRADUALLY STRENGTHEN FROM THE RIO GRANDE VALLEY ACROSS
THE PLAINS AS LEE-SIDE TROUGHING BECOMES RE-ESTABLISHED OVER THE
REGION. LOW LEVEL MOISTURE FLUX WILL ALSO INCREASE THROUGH TONIGHT
FROM THE SRN HIGH PLAINS NWD/NEWD TO THE MO VALLEY AS BUILDING UPPER
RIDGE TRANSPORTS ELEVATED MIXED LAYER AIR MASS EWD OFF THE ROCKIES
ESCARPMENT. LASTLY...GREAT LAKES CUT-OFF LOW WILL BEGIN TO BE
DISPLACED ESEWD THIS PERIOD AS A STRONG UPSTREAM TROUGH...CURRENTLY
OVER BC...MOVES EAST.

...EAST COAST FROM SERN VA TO FL...
LARGE SCALE ASCENT WILL SPREAD EAST ATOP MOIST BUT ONLY MARGINALLY
UNSTABLE AIR MASS FROM THE APPALACHIANS EWD ACROSS MUCH OF NC AND VA
THROUGH THE DAY. STRONGER INSTABILITY OVER MUCH OF THIS REGION MAY
BE INHIBITED BY WIDESPREAD CONVECTIVE DEBRIS FROM ONGOING MCS
CURRENTLY CROSSING THE SRN APPALACHIANS. HOWEVER...A NARROW WINDOW
OF OPPORTUNITY FOR GREATER DESTABILIZATION IS SUGGESTED IN LATEST
GUIDANCE FROM ERN SC ACROSS ERN NC WHERE MLCAPE IN THE RANGE OF
500-1500 J/KG MAY DEVELOP AHEAD OF MORE FOCUSED FORCING AND
STRENGTHENING DEEP-LAYER FLOW NEAR POSSIBLE FRONTAL WAVE. THIS
SHOULD ALLOW STORMS TO INCREASE IN INTENSITY/ORGANIZATION AS THE
FRONT MOVES EAST FROM AFTERNOON THROUGH EVENING. A FEW MARGINAL
HAIL/WIND EVENTS APPEAR POSSIBLE WITH THIS ACTIVITY...ALONG WITH A
LOW PROBABILITY TORNADO THREAT.

FARTHER SOUTH...STRONG IMPULSE ROTATING THROUGH THE BASE OF THE
LARGE SCALE TROUGH WAS RESULTING IN STORMS INTENSIFYING ACROSS THE
FL PANHANDLE EARLY TODAY. THIS ACTIVITY MAY CONTINUE EAST INTO SRN
GA AND NRN FL THIS MORNING WITH THE CHANCE FOR WIND DAMAGE AND HAIL
CONTINUING. LARGE SCALE HEIGHT FALLS WITH THE UPPER TROUGH WILL
COMBINE WITH INCREASING DIURNAL INSTABILITY ACROSS FL TO PROMOTE
ADDITIONAL STORM DEVELOPMENT THROUGH THE DAY. DEEP LAYER SHEAR OVER
THE REGION WILL STRENGTHEN AND...COUPLED WITH POTENTIAL FOR
SEABREEZE INTERACTIONS...RESULT IN ORGANIZED STORM UPDRAFTS WITH A
CHANCE FOR HAIL/WIND AND PERHAPS A TORNADO.

...WEST TX/ERN NM...
UPSLOPE FLOW AND RETURN OF 50S F DEWPOINTS TO THE SRN HIGH PLAINS
WILL COMBINE WITH STRONG HEATING/MIXING TO SUPPORT ISOLATED
HIGH-BASED CONVECTIVE DEVELOPMENT OVER THE HIGHER TERRAIN BY LATE
AFTERNOON. EFFECTIVE SHEAR WILL BE MORE THAN ADEQUATE TO PROMOTE
UPDRAFT ROTATION WITH A COUPLE OF THE MORE PERSISTENT CELLS POSSIBLY
PRODUCING LARGE HAIL OR A SEVERE WIND GUST. LACK OF GREATER
INSTABILITY AND STRONGER FORCING SHOULD KEEP SEVERE POTENTIAL
LIMITED TO A FEW HOURS EITHER SIDE OF MAX HEATING.

...SERN LOWER MI/NRN IND/NWRN OH...
LIMITED CLOUD COVER AND BOUNDARY LAYER HEATING SHOULD ALLOW FOR
LAPSE RATES TO STEEPEN ACROSS LOWER MI AND PARTS OF THE UPPER
MIDWEST AS CUT-OFF LOW SPREADS ESEWD DURING THE DAY. WEAK CAPE AND
FORCING FOR ASCENT ON THE NOSE OF MID LEVEL JET STREAK DEVELOPING
SEWD ACROSS IL/IND SHOULD SUPPORT LOW-TOPPED TSTM INITIATION WITH
THE CHANCE FOR SCATTERED HAIL GIVEN LOW FREEZING LEVELS BENEATH/NEAR
THE UPPER LOW.

...NERN KS TO MO...
LOW LEVEL MOISTURE BEING TRANSPORTED BENEATH STRONG CAP WILL
ENCOUNTER A ZONE OF FRONTOGENESIS ACROSS THE SCNTRL PLAINS/MO RIVER
VALLEY FROM LATE TONIGHT INTO EARLY SUNDAY. MODEL GUIDANCE IS IN
GOOD AGREEMENT THAT THIS PROCESS SHOULD ENHANCE THE CHANCES FOR
ELEVATED TSTM DEVELOPMENT IN A BAND FROM EXTREME SERN NEB...ACROSS
NERN KS...AND INTO NRN MO. IT IS POSSIBLE THAT ONE OR TWO STORMS
COULD PRODUCE MARGINALLY SEVERE HAIL BEFORE DAYBREAK SUNDAY.

..CARBIN/TAYLOR.. 04/22/2006