[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 261308
SWODY1
SPC AC 261306

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0806 AM CDT FRI MAY 26 2006

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE NRN/CENTRAL PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID ATLANTIC REGION
INTO THE APPALACHIANS AND TN VALLEY/MID SOUTH...

...SYNOPSIS...
UPPER LOW OVER THE GREAT LAKES IS FORECAST TO CONTINUE EWD TODAY
ACROSS THE LOWER LAKES...OPENING INTO A TROUGH TONIGHT AS IT MOVES
TOWARD THE ATLANTIC COAST.  WATER VAPOR IMAGERY INDICATES THE
UPSTREAM FLOW PATTERN IS BEGINNING TO AMPLIFY PER MODEL FORECASTS
WITH A RIDGE BEGINNING TO BUILD OVER THE PLAINS AS TROUGH DEEPENS
ALONG THE PACIFIC COAST.  THESE SYSTEMS WILL PROGRESS EWD THROUGH
THE PERIOD WITH THE RIDGE REACHING THE MS VALLEY WHILE THE TROUGH
SETTLES OVER THE PACIFIC NORTHWEST BY 27/12Z.

AT THE SURFACE...A LOW OVER LOWER MI IS EXPECTED TO MOVE EWD INTO NY
THIS AFTERNOON AND ACROSS NEW ENGLAND TONIGHT. COLD FRONT TRAILING
SWWD FROM THE LOW WILL MOVE ACROSS THE APPALACHIANS TOWARD THE MID
ATLANTIC COAST...CONTINUING WWD AS A STATIONARY FRONT THROUGH THE TN
VALLEY...THEN LIFTING NWD AS A WARM FRONT INTO THE MO RIVER VALLEY
AS A LOW MOVES INTO THE NRN HIGH PLAINS TONIGHT.  A SERIES OF
CONVECTIVE OUTFLOW BOUNDARIES ARE LOCATED AHEAD OF THE FRONT FROM VA
WWD INTO THE TN VALLEY AND CENTRAL PLAINS...AND THESE MAY PROVIDE
ADDITIONAL FOCI FOR REDEVELOPMENT OF THUNDERSTORMS LATER TODAY. 
LASTLY...A NORTH-SOUTH DRY LINE IS EXPECTED TO BECOME BETTER
ESTABLISHED THIS AFTERNOON ACROSS THE CENTRAL/SRN HIGH PLAINS.

...MID ATLANTIC STATES INTO CAROLINAS AND SRN APPALACHIANS...
DYNAMIC FORCING FOR LARGE SCALE ASCENT ASSOCIATED WITH GREAT LAKES
UPPER LOW IS EXPECTED TO SPREAD EWD ACROSS THIS REGION
TODAY...ENHANCED BY MESOSCALE CONVERGENCE ALONG SURFACE TROUGH
EXPECTED TO DEVELOP IN THE LEE OF THE APPALACHIANS. EARLY VISIBLE
IMAGERY SHOWS CLEAR SKIES FROM THE DELMARVA ACROSS SERN VA INTO MUCH
OF THE CAROLINAS.  ALTHOUGH SOME CLOUDS ARE SPREADING EWD ACROSS THE
APPALACHIANS BREAKS IN THE CLOUD COVER ARE LIKELY TO OCCUR.  THIS
WILL ALLOW STRONGER DIURNAL HEATING ACROSS PARTS OF THIS REGION
TODAY WHERE DEW POINTS ARE EXPECTED TO INCREASE INTO THE 65-70F
RANGE. 12Z REGIONAL SOUNDINGS EXHIBIT MODERATE STEEP LAPSE RATES
WHICH WILL INCREASE MAGNITUDE OF INSTABILITY THIS AFTERNOON /MLCAPE
OF 1500-2000 J/KG/.

SEVERAL BANDS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON ALONG THE LEE TROUGH EAST OF THE APPALACHIANS...AND
ALONG/AHEAD OF THE COLD FRONT OVER WV/WRN VA/WRN PA REGION AS UPPER
SYSTEM MOVES ACROSS THE AREA DURING THE AFTERNOON.  STRONGEST DEEP
LAYER SHEAR OF 30-35 KT IS EXPECTED ACROSS THE CAROLINAS NWD INTO
THE DELMARVA REGION WHICH WILL ENHANCE STORM ORGANIZATION AND
INTENSITY.  A FEW SEVERE THUNDERSTORMS WILL BE POSSIBLE MAINLY THIS
AFTERNOON AND EVENING WITH PRIMARY THREAT FOR DAMAGING WINDS AND
LARGE HAIL.  ADDITIONAL SEVERE STORMS MAY DEVELOP WWD INTO PARTS OF
GA AND AL ALONG REMNANTS OF OUTFLOW BOUNDARIES ALONG SRN EDGE OF
UPPER TROUGH WHERE UNSTABLE ENVIRONMENT (MLCAPE OF 2000-3000 J/KG)
WILL BE LOCATED.

...MID SOUTH REGION...
ANIMATED RADAR IMAGERY SUGGESTS MCS MOVING ACROSS SERN KS/NERN OK
HAS GENERATED AN MCV.  THIS FEATURE MAY CONTINUE MOVING SEWD TOWARD
AR TODAY...WHERE 12Z LZK SOUNDING SHOWS VERY STEEP LAPSE RATE IN THE
800-550 MB LAYER.  THE CAP IS EXPECTED TO GRADUALLY WEAKEN AS LOW
LEVEL HEATING COUPLES WITH POSSIBLE ASCENT ASSOCIATED WITH THE
UPSTREAM MCV...WITH POTENTIAL FOR THUNDERSTORMS TO REDEVELOP THIS
AFTERNOON.  STRONG INSTABILITY WITH MLCAPE OF 2000-3000 J/KG
SUGGESTS THREAT FOR SEVERE THUNDERSTORMS ACROSS THIS AREA.

...CENTRAL/NRN PLAINS...
ONGOING ELEVATED THUNDERSTORMS FROM SOUTH CENTRAL NEB INTO PARTS OF
KS ARE EXPECTED TO CONTINUE MOVING EWD/ESEWD THIS MORNING.  STRONGER
CELLS IN KS MAY HAVE POTENTIAL TO PRODUCE HAIL.  OTHER SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATER THIS AFTERNOON AND
EVENING OVER THE HIGH PLAINS FROM NERN CO NWD ACROSS WRN PARTS OF
THE DAKOTAS AND ERN MT...AS WEAK PERTURBATIONS WITHIN STRENGTHENING
SWLY FLOW ALOFT MOVE ACROSS WRN EDGE OF LOW LEVEL MOISTURE FIELD. 
12Z SOUNDINGS SHOW STEEP MID LEVEL LAPSE RATES IN PLACE...AND CLEAR
SKIES WILL PROMOTE STRONG INSOLATION WHICH WILL CONTRIBUTE TO
DESTABILIZATION.  DEEP LAYER SHEAR WILL BE THE STRONGEST OVER THE
NRN HIGH PLAINS REGION WITH 40-50 KT IN THE LOWEST 6 KM...WITH SHEAR
OF 30-35 KT EXTENDING SWD INTO THE CENTRAL PLAINS.  SEVERAL CLUSTERS
OF STRONG/SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGH
PLAINS AND MOVE NEWD LATE THIS AFTERNOON AND EVENING...WITH SOME OF
THE ACTIVITY LIKELY PERSISTING INTO THE OVERNIGHT HOURS AS THE LOW
LEVEL JET INTENSIFIES AFTER DARK.

...SRN HIGH PLAINS...
VERY UNSTABLE ENVIRONMENT IS EVIDENT IN 12Z SOUNDINGS AT AMA AND MAF
WITH NEARLY DRY ADIABATIC LAPSE RATES PRESENT ABOVE THE PBL.  THIS
WILL CONTRIBUTE TO STRONGLY UNSTABLE ENVIRONMENT EAST OF THE DRY
LINE WHERE MLCAPE OF 2000-3000 J/KG IS EXPECTED.  FORCING FOR LARGE
SCALE ASCENT WILL BE MINIMAL AS THE UPPER RIDGE MOVES OVER THE AREA
AND DRY LINE CONVERGENCE IS ALSO EXPECTED TO BE WEAK SUGGESTING
THUNDERSTORM ACTIVITY WILL BE ISOLATED AT BEST.  HOWEVER...THE 06Z
ETA AND NAM-WRF PARALLEL AND THE 00Z EXPERIMENTAL HIGH RESOLUTION
WRF-NMM ALL DEVELOP CONVECTION OVER PARTS OF WRN TX LATE THIS
AFTERNOON/EVENING.  GIVEN THE WEAK SHEAR A FEW PULSE STORMS OR
MULTICELL CLUSTERS MAY DEVELOP WITH POTENTIAL FOR ISOLATED LARGE
HAIL/DOWNBURSTS.

...SRN FL...
WILL MAINTAIN LOW PROBABILITY FOR SEVERE STORMS ACROSS THIS AREA
TODAY AS STRONGER BRANCH OF MID LEVEL FLOW IS FORECAST OVER THE
AREA...ENHANCING DEEP LAYER SHEAR.  PRIMARY THREAT IS EXPECTED OVER
THE INTERIOR AND EAST COAST OF SOUTH FL AS STORMS PROGRESS EWD
TOWARD EAST COAST SEA BREEZE FRONT.

..WEISS/JEWELL.. 05/26/2006