[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 230615
SWODY2
SPC AC 230614

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0114 AM CDT SUN APR 23 2006

VALID 241200Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN PLAINS TO THE
LOWER OH VALLEY...

...SYNOPSIS...
LARGE WRN STATES UPPER TROUGH...THOUGH WEAKENING WITH TIME...WILL
MOVE NE TOWARD ROCKIES/HIGH PLAINS...WITH SHORT WAVE TROUGH WITHIN
BASE OF THIS SYSTEM APPROACHING CENTRAL/SRN HIGH PLAINS BY 12Z
TUESDAY.  HEIGHT FALLS WITH APPROACH OF WRN TROUGH AND ALSO WITH
STRONGER UPPER TROUGH DIGGING SEWD ACROSS THE GREAT LAKES AND MID
MS/OH VALLEYS EXPECTED TO EFFECTIVELY BREAK DOWN RIDGE OVER
CENTRAL/SRN PLAINS.  BAND OF 40-50 KT WSWLY FLOW SHOULD EXTEND FROM
SWRN STATES ACROSS THE SRN PLAINS TO OH/TN VALLEY AND MID-ATLANTIC
STATES.

MID/UPPER LEVEL CONFLUENT FLOW REGIME TRANSLATING SEWD ALONG MID/
LOWER MO VALLEY WILL ALLOW LARGE SURFACE ANTICYCLONE TO BUILD S/SEWD
ACROSS THE PLAINS/MS VALLEY IN WAKE OF STRONG/PROGRESSIVE COLD FRONT
ASSOCIATED WITH NRN STREAM SYSTEM.  BY LATE MONDAY AFTERNOON...COLD
FRONT EXPECTED TO EXTEND FROM CENTRAL GREAT LAKES SWWD ACROSS LOWER
MO VALLEY TO CENTRAL OK...AND THEN WSWWD THROUGH NWRN TX-NERN NM.  A
SURFACE LOW SHOULD TRACK NEWD THROUGH THE OH VALLEY MONDAY NIGHT AS
NRN EXTENT OF COLD FRONT SPREADS EWD TOWARD THE LOWER GREAT
LAKES/CENTRAL APPALACHIANS.  ANOTHER SURFACE WAVE/TRIPLE POINT IS
EXPECTED TO EVOLVE OVER CENTRAL OK BY MONDAY AFTERNOON...AS A DRY
LINE MIXES EWD AND THE COLD FRONT CONTINUES ITS TREK SSEWD THROUGH
THE SRN PLAINS.

...SRN PLAINS ENE TO OZARKS/LOWER MO VALLEY...
LOW-LEVEL MOISTURE WILL CONTINUE TO ADVECT NWD DAY 1 INTO DAY 2
ACROSS THE SRN PLAINS BENEATH ELEVATED MIXED LAYER...WITH SOMEWHAT
MORE SUBSTANTIAL WARM SECTOR MOISTENING EXPECTED MONDAY THAN HAS
BEEN OBSERVED ACROSS THIS REGION PAST SEVERAL DAYS.  THIS WILL
CONTRIBUTE TO A VERY UNSTABLE AIR MASS /MLCAPE 2500+ J/KG/ ACROSS
NRN TX TO SERN KS/SWRN MO ALONG/S OF COLD FRONT AND EAST OF TRIPLE
POINT AND TRAILING DRY LINE.

ONE OR TWO MCS/S SHOULD BE ONGOING 12Z MONDAY ACROSS LOWER MO VALLEY
TO OZARKS REGION ALONG/N OF QUASI-STATIONARY BOUNDARY WHICH SHOULD
REMAIN LOCATED FROM ERN KS/SRN MO TO TN VALLEY PRIOR TO COLD FRONTAL
PASSAGE.  THIS ACTIVITY WILL BE ASSOCIATED WITH WAA REGIME ALONG
NOSE OF STRONG NOCTURNAL SWLY LLJ.  THIS ACTIVITY SHOULD TEND TO
WEAKEN MONDAY MORNING WITH EWD EXTENT AS LLJ WITHIN WARM SECTOR
BACKS TO SLY IN ADVANCE OF APPROACHING SRN STREAM SHORT WAVE TROUGH.
 
EML IS EXPECTED TO CAP WARM SECTOR THROUGH MID AFTERNOON...WITH NEW
THUNDERSTORM DEVELOPMENT LIKELY BY LATE AFTERNOON ACROSS SWRN
MO/SERN KS INTO NRN OK BY MID AFTERNOON AS STRONG SURFACE
HEATING...INCREASING LOW-LEVEL CONVERGENCE...AND WEAK HEIGHT FALLS
AID IN WEAKENING CINH. STRONG DEEP LAYER SHEAR ORIENTED NORMAL TO
DRY LINE SHOULD RESULT IN POTENTIAL FOR DISCRETE SUPERCELLS WITH
INITIAL ACTIVITY CAPABLE OF PRODUCING TORNADOES...VERY LARGE
HAIL...AND DAMAGING WINDS.  ACTIVITY SHOULD EVOLVE INTO A LINEAR
STRUCTURE AS THE COLD FRONT PROGRESSES S/SEWD INTO THE LOWER OH
VALLEY AND OZARKS TO NRN TX MONDAY NIGHT.

...OH/TN VALLEYS TO NC...
MOISTURE RETURN IS EXPECTED INTO THE OH VALLEY ALONG NWRN PERIPHERY
OF SERN STATES SURFACE HIGH.  SURFACE HEATING WITHIN THIS MOISTENING
AIR MASS EXPECTED TO RESULT IN SUFFICIENT INSTABILITY ACROSS THE
LOWER OH VALLEY IN ADVANCE OF EARLY MORNING MCS OVER SRN MO.  THIS
MAY ALLOW FOR SOME INCREASE IN STORM INTENSITY AND/OR SPORADIC STORM
DEVELOPMENT ALONG BAROCLINIC ZONE ACROSS PARTS OF KY/TN TO WRN NC
WHERE WEAK-MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR WOULD
SUPPORT ISOLATED SEVERE STORMS.

GREATER STORM COVERAGE AND OVERALL SEVERE THREAT IS EXPECTED MONDAY
EVENING/NIGHT AS AFTERNOON STORMS ACROSS MO GROW UPSCALE INTO A
FORWARD PROPAGATING MCS THROUGH THE OH VALLEY. STRONG WSWLY LLJ
DEVELOPING ALONG OH VALLEY AFTER 25/00Z IN RESPONSE TO STRONG HEIGHT
FALLS MAY INCREASE THE THREAT FOR DAMAGING WINDS... WITH GREATEST
THREAT INTO THE LOWER OH VALLEY WHERE INSTABILITY WILL BE THE
GREATEST.

..PETERS.. 04/23/2006