SWODY1
SPC AC 220533
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1233 AM CDT SUN APR 22 2007
VALID 221200Z - 231200Z
..THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL PLAINS TO
WI...
..SYNOPSIS...
MID/UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER
NERN NM AND SERN CO -- IS FCST TO CONTINUE EJECTING NEWD DURING
DAY-1 FROM WRN KS TO VICINITY IA/WI BORDER. NEARLY COLLOCATED SFC
LOW LIKEWISE WILL LIFT NEWD...MOVING FROM N-CENTRAL KS NEWD ACROSS
SERN NEB TO SWRN IA THROUGH AFTERNOON HOURS. SFC FRONTAL ZONE WILL
EXTEND NWD FROM THIS LOW ACROSS CENTRAL NEB...THEN NEWD OVER SERN SD
AND MN...DRIFTING EWD ACROSS NERN PLAINS AND UPPER MS VALLEY AS COLD
FRONT. DRYLINE WILL ARC SEWD THEN SWD FROM VICINITY SFC
LOW...ACROSS CENTRAL/ERN KS AND CENTRAL/ERN OK...MOVING NEWD ACROSS
KS/MO BORDER AND INTO NWRN MO BY AROUND 23/00Z.
FARTHER W...NEXT SIGNIFICANT TROUGH -- WHICH WILL SUBSTANTIALLY
IMPACT DAY-2 AND DAY-3 SVR POTENTIAL OVER CENTRAL CONUS -- IS FCST
TO MOVE INLAND FROM PACIFIC COAST. BROAD MID/UPPER LEVEL CYCLONE
SHOULD CONSOLIDATE BY 23/12Z CENTERED OVER NV. ISOLATED GEN TSTM
POTENTIAL EXISTS ACROSS PORTIONS WRN INTERMOUNTAIN REGION AND
WRN/NRN GREAT BASIN.
..CENTRAL PLAINS TO UPPER MS VALLEY...
PRIND SOME DESTABILIZATION WILL OCCUR BEHIND INITIAL ARC OF
CLOUDS/PRECIP THAT WILL MOVE NEWD ACROSS THIS AREA BY LATE MORNING
AND EARLY AFTERNOON. SCATTERED TSTMS ARE FCST TO DEVELOP AS EARLY
AS MIDDAY INVOF SFC LOW...BUILDING SEWD ALONG LEADING EDGE OF DRY
SLOT. THIS ACTIVITY WILL SHIFT NEWD ACROSS NERN KS...SERN
NEB...NERN MO..SWRN IA REGION.
FCST SOUNDINGS SUGGEST LIMITED SFC HEATING AND VERTICAL SHEAR
PROFILES E AND ESE OF SFC LOW SHOULD BE FAVORABLE...WITH 45-55 KT
DIURNAL LLJ ENLARGING HODOGRAPH. DURING TIME FRAME WHEN TSTMS
REMAIN RELATIVELY DISCRETE...0-1 KM SRH ABOVE 200 J/KG AND ROUGHLY
50 KT 0-6 KM SHEAR WILL FAVOR SUPERCELLS AND POTENTIAL FOR TORNADOES
OVER PORTIONS ERN KS AND W-CENTRAL/NWRN MO. DEEP-LAYER SHEAR
PROFILES SHOULD WEAKEN FARTHER NW ACROSS S-CENTRAL/E-CENTRAL
NEB...BENEATH COLD CORE REGION OF UPPER LOW. HOWEVER...FCST LOW
LEVEL LIFT AND VORTICITY ALSO WILL BE FAVORABLE FOR TORNADO
POTENTIAL CLOSER TO SFC/UPPER LOW...IN COLD CORE REGION. COMPLEX OF
SVR TSTMS WITH DAMAGING WIND AND LARGE HAIL MAY EVOLVE AND MOVE NEWD
ACROSS PORTIONS IA/NRN MO DURING EVENING HOURS.
SOME PORTION OF THIS AREA MAY REQUIRE UPGRADE ONCE SOME MESOSCALE
UNCERTAINTIES ARE RESOLVED REGARDING DESTABILIZATION AND TIMING/MODE
OF CONVECTIVE FORCING.
SCATTERED TSTMS ALSO MAY DEVELOP ALONG BAROCLINIC ZONE EXTENDING
POLEWARD OF LOW...WITH HAIL AND DAMAGING GUSTS POSSIBLE. THIS
POTENTIAL SHOULD BE MAINLY BEFORE DARK...AND STRONGLY TIED TO
STRENGTH/DURATION OF SFC HEATING ALONG AND S OF BAROCLINIC
BOUNDARY...WITH DEW POINTS GENERALLY 50S F.
..ERN OK...OZARKS...
SVR POTENTIAL BECOMES MUCH MORE CONDITIONAL WITH SWD EXTENT FROM
SERN KS AND SWRN MO SWD ACROSS ERN OK AND NWRN AR. VERTICAL SHEAR
PROFILES ARE FCST TO BE FAVORABLE FOR SUPERCELLS WITH 45-60 KT 500
MB FLOW AND 0-6 KM SHEAR VECTOR MAGNITUDES ALSO IN 45-60 KT RANGE.
SFC DEW POINTS MID 50S TO LOW 60S SHOULD BE
COMMON...HOWEVER...CONVECTIVE INITIATION AND ESPECIALLY SUSTAINED
TSTM POTENTIAL BECOMES LESS PROBABLE WITH DISTANCE FROM
COMPACT/DEEP-LAYER CYCLONE AND ASSOCIATED MID/UPPER LEVEL ASCENT
MAXIMA. WITH SWD EXTENT...PRIND LOW-MIDLEVEL LAPSE RATES ABOVE
BOUNDARY LAYER WILL DIMINISH...AND MLCINH WILL INCREASE. ALSO...
STRONGEST ISALLOBARIC FORCING WILL BE N OF THIS AREA --- FROM LOWER
MO VALLEY INTO IA -- SO SFC WINDS SHOULD HAVE WLY COMPONENT THAT
WILL LIMIT CONVERGENCE. ANY SUSTAINED CONVECTION THAT MAY DEVELOP
THIS AFTERNOON MAY PRODUCE LARGE HAIL AND DAMAGING GUSTS...BUT
POTENTIAL APPEARS TOO CONDITIONAL FOR CATEGORICAL OUTLOOK ATTM.
.EDWARDS/JEWELL.. 04/22/2007
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