[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 150559
SWODY1
SPC AC 150557

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT SAT APR 15 2006

VALID 151200Z - 161200Z

...THERE IS A MDT RISK OF SVR TSTMS CENTRAL/ERN NEB...PORTIONS
WRN/SRN IA...N-CENTRAL/NWRN MO...PORTIONS N-CENTRAL/NERN KS....

...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM WRN NEB AND ERN
KS TO CENTRAL INDIANA....

...THERE IS A SLGT RISK OF SVR TSTMS SERN OH...CENTRAL APPALACHIANS
TO COASTAL MD/VA/NERN NC....

...SYNOPSIS...
IN MID/UPPER LEVELS...EXPECT PROGRESSIVE SHORTWAVE TRAIN WITHIN
LARGER SCALE PATTERN THAT FEATURES CENTRAL CONUS RIDGE...AND TROUGHS
 OVER NERN PACIFIC AND QUE/NEW ENGLAND REGIONS.  MOST CRITICAL DAY-1
 SYSTEM WILL BE STRONG TROUGH AND EMBEDDED MIDLEVEL CYCLONE -- NOW
EVIDENT IN MOISTURE CHANNEL IMAGERY OVER LOWER CO RIVER VALLEY. 
THIS FEATURE WILL CONTINUE TO MOVE NEWD FROM S-CENTRAL ROCKIES
ACROSS CENTRAL PLAINS...DECELERATING LATE IN PERIOD OVER ERN NEB/SRN
IA/NERN MO REGION AS IT PENETRATES LARGE SCALE RIDGE POSITION. 
MEANWHILE...WEAK/LOW-AMPLITUDE SHORTWAVE PERTURBATION NOW INVOF MEAN
RIDGE -- OVER SERN SASK/SRN MB -- SHOULD MOVE SEWD ACROSS GREAT
LAKES TOWARD DELMARVA REGION BY 16/00-16/06Z TIME FRAME.  STRONG
SHORTWAVE TROUGH NOW OVER NERN/ERN ONT SHOULD DIG ESEWD ACROSS QUE
AND NRN NEW ENGLAND THROUGH PERIOD.

AT SFC...QUASISTATIONARY FRONTAL ZONE IS ANALYZED FROM CENTRAL/WRN
PORTIONS KS/OK BORDER NEWD ACROSS CENTRAL IL...THEN SEWD OVER
CENTRAL VA.  PORTION FROM IL-WV IS CONVECTIVELY
REINFORCED...DISPLACED SW OF MORE DIFFUSE SYNOPTIC WARM FRONTAL
POSITION OVER LOWER GREAT LAKES REGION.  THIS BOUNDARY SHOULD REMAIN
NEARLY STATIONARY FROM IL THROUGH CENTRAL APPALACHIANS DURING MOST
OF PERIOD...WHILE MOVING SWD ACROSS VA.  WRN PORTION SHOULD RETREAT
NWD AS WARM FRONT ACROSS CENTRAL PLAINS AND MID MS VALLEY...AHEAD OF
VIGOROUS CENTRAL PLAINS CYCLOGENESIS.  THIS LOW -- NOW WEAKLY
EVIDENT OVER SERN CO -- SHOULD DEEPEN CONSIDERABLY AS IT MOVES NEWD
TO N-CENTRAL/NERN NEB BY 16/00Z.  DURING DAY...BLENDED DRYLINE AND
PACIFIC FRONT WILL MOVE EWD ACROSS PORTIONS SRN NEB...WRN/CENTRAL KS
AND WRN/CENTRAL OK S OF SFC LOW.

...CENTRAL PLAINS...
POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT -- RELATIVELY CONFINED
GEOGRAPHICALLY BUT WITH THREAT OF SEVERAL VERY DAMAGING SUPERCELLS
-- IS POSSIBLE IN AND NEAR MDT RISK AREA.  TORNADOES AND DAMAGING
HAIL/GUSTS ARE EXPECTED.

PRIMARY CONCERN WILL BE FROM MID-AFTERNOON THROUGH EVENING...THOUGH
EARLIEST SFC-BASED SEVERE TSTMS MAY INITIATE DURING EARLY AFTERNOON
OVER CENTRAL HIGH PLAINS...JUST AHEAD OF EJECTING SFC CYCLONE. 
DESTABILIZATION ALOFT SHOULD BE VIGOROUS WITH THIS SYSTEM AS IT
APCHS...GIVEN -22 DEG C 50 MB TEMPS OBSERVED IN 15/00Z NKX
RAOB...100-120 M/12 HOUR HEIGHT FALLS OBSERVED IN MIDLEVELS FROM
THERE NEWD ACROSS NRN AZ...CONSIDERABLE AMOUNT OF THUNDER DETECTED
IN PAST FEW HOURS ACROSS SRN NV/UT...AND INTENSE DPVA FCST TO SHIFT
ENEWD ACROSS KS/NEB BY 16/00Z.

ANY SUPERCELLS DEVELOPING ALONG/AHEAD OF DRYLINE DURING AFTERNOON
SHOULD MOVE NEWD OVER KS AND NNEWD TO NNWWD OVER NEB.  TORNADO
POTENTIAL SHOULD BE GREATEST INVOF WARM FRONT WHERE INDIVIDUAL TSTMS
THAT DEVELOPED FARTHER SW HAVE HAD TIME TO MATURE...AND TO ENCOUNTER
AREA OF ENHANCED VORTICITY/SRH AND LOWERED LCL CHARACTERIZING
BAROCLINIC ZONE.  CONVECTIVE COVERAGE SHOULD DIMINISH WITH SWD
EXTENT ACROSS KS/OK BECAUSE OF DIMINISHING LOW AND MIDDLE LEVEL
FORCING...STRENGTHENING CINH...AND WEAKER MLCAPE RELATED TO MORE
VIGOROUS MIXING/DRYING OF MOIST SECTOR BOUNDARY LAYER. 
LARGE/DAMAGING HAIL...SEVERE GUSTS AND PERHAPS A FEW TORNADOES ARE
POSSIBLE FROM ANY TSTMS THAT DO FORM FROM CENTRAL/ERN KS SWD ALONG
DRYLINE.  HOWEVER...SEVERE POTENTIAL BECOMES MORE STRONGLY
CONDITIONAL WITH SWD EXTENT UNTIL THUNDER POTENTIAL GETS TOO LOW TO
JUSTIFY SEVERE PROBABILITIES.

...MID MS VALLEY -- ERN MO/IL/INDIANA...
ADDITIONAL SEVERE TSTMS MAY DEVELOP DURING AFTERNOON/EVENING FARTHER
SE ACROSS WARM FRONT AND ADJACENT MOIST SECTOR...OVER PORTIONS
MO/IL. VERTICAL SHEAR PROFILES...WHILE NOT AS INTENSE AS IN ZONE OF
STRONG ISALLOBARIC FORCING NEAR SFC LOW -- STILL MAY  SUPPORT SEVERE
MULTICELLS...AND PERHAPS A FEW HEAVY-PRECIP SUPERCELL/BOW
MORPHOLOGIES.  MOST FAVORABLE KINEMATIC AND THERMODYNAMIC PROFILES
WILL BE INVOF SFC WARM FRONT WHERE BACKED SFC WINDS ENHANCE
DEEP-LAYER SHEARS...THOUGH WEAK LOW LEVEL WINDS MAY KEEP BOUNDARY
LAYER HODOGRAPHS RELATIVELY SMALL.  LITTLE OR NO MID/UPPER LEVEL
FORCING IS LIKELY FOR MUCH OF PERIOD...THOUGH CONVECTION MAY BE
AIDED BY LOW LEVEL WAA...FRONTAL LIFT AND WEAK CINH RESULTING FROM
AFTERNOON INSOLATION.  ALTHOUGH MODEL FCST DEW POINTS APPEAR
OVERDONE ONCE AGAIN...WELL HEATED/MIXED BOUNDARY LAYERS AND UPPER
50S/LOW 60S DEW POINTS MAY SUPPORT 2000-2500 J/KG MLCAPES FROM
15/21Z-16/00Z. SUPERCELL POTENTIAL MAY INCREASE AFTER DARK OVER
CENTRAL/ERN MO AS STRONGER WINDS ALOFT OVERSPREAD AREA AHEAD OF
MIDLEVEL LOW.

... CENTRAL APPALACHIANS TO TIDEWATER REGION...
CONTINUED POTENTIAL EXISTS THROUGH MUCH OF PERIOD FOR CLUSTERS OF
STRONG-SEVERE TSTMS TO FORM INVOF PERSISTENT BAROCLINIC ZONE.  MOST
PROBABLE SEVERE TSTM THREAT WILL BE FROM AFTERNOON THROUGH EVENING
FROM WV THROUGH WRN/CENTRAL VA...SHIFTING ESEWD ACROSS PORTIONS
ERN/SRN VA AND NRN NC. STEEP MIDLEVEL LAPSE RATES WILL CONTRIBUTE
TO MLCAPES POTENTIALLY EXCEEDING 2000 J/KG IN SOME PARTS OF THIS
REGION.  INVERTED-V THERMODYNAMIC PROFILES IN FCST SOUNDINGS RESULT
FROM STRONG HEATING/MIXING OF BOUNDARY LAYER ALONG AND S OF FRONTAL
ZONE...CONTRIBUTING TO POTENTIAL FOR BOTH HAIL AND DAMAGING GUSTS TO
REACH SFC.

...NERN CONUS...
POCKETS OF FAVORABLE SFC HEATING WITH WEAK CINH MAY CONTRIBUTE TO
CONVECTIVE POTENTIAL FROM LATE MORNING THROUGH AFTERNOON...WITH SOME
HAIL/GUSTS NEAR SEVERE LEVELS POSSIBLE.  SFC DEW POINTS MID
50S...ISOLATED NEAR 60 F...ARE POSSIBLE FROM ERN PA ACROSS PORTIONS
NJ/SERN NY W OF WARM FRONT THAT WILL BE MOVING EWD OVER THIS REGION.
 NEARLY UNIDIRECTIONAL WLY-WNWLY WIND PROFILES ARE FCST THROUGH MOST
OF TROPOSPHERE.  THIS SHOULD LIMIT CONVERGENCE AND OVERALL COVERAGE
OF TSTMS...AS WELL AS STRENGTH OF DEEP-LAYER SHEAR. 
HOWEVER...MID/UPPER FLOW WILL BE ENHANCED S OF ONT/QUE
TROUGH...AIDING ORGANIZATION OF ANY SUSTAINED TSTMS THAT DO DEVELOP.

..EDWARDS/GRAMS.. 04/15/2006