[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 010635
SWODY2
SPC AC 010634

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1234 AM CST SAT APR 01 2006

VALID 021200Z - 031200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF EASTERN
IOWA...NORTHERN MISSOURI...AND NORTHERN ILLINOIS...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
FROM THE SRN/CNTRL PLAINS TO THE OH/TN VALLEYS AND PORTIONS OF THE
LOWER MS VALLEY...

...SIGNIFICANT SEVERE WEATHER EPISODE APPEARS POSSIBLE ACROSS
PORTIONS OF THE MIDDLE MS VALLEY AND MIDWEST ON SUNDAY...

...SYNOPSIS...
ACTIVE AND PROGRESSIVE WAVE TRAIN WILL CONTINUE TO CROSS THE LOWER
48 STATES THROUGH THE WEEKEND. A LEAD SHORT WAVE TROUGH WILL CROSS
THE NORTHEAST TODAY AS THE NEXT SHORT WAVE TROUGH MOVES QUICKLY OVER
THE WRN STATES AND THEN EMERGES OVER THE GREAT PLAINS THROUGH EARLY
SUNDAY MORNING. THIS NEXT SIGNIFICANT SHORT WAVE FEATURE WILL THEN
APPROACH THE MS VALLEY DURING THE DAY SUNDAY WITH 70KT MID LEVEL JET
FORECAST TO ROTATE THROUGH THE BASE OF THE TROUGH AND ACROSS MO AND
IL THROUGH LATE SUNDAY EVENING. STRONG DYNAMICS ON THE NOSE OF THE
MID/UPPER LEVEL JET CORE AND LARGE SCALE HEIGHT FALLS OF 90-120M PER
12H WILL INDUCE SURFACE CYCLOGENESIS OVER THE HIGH PLAINS THROUGH
THE DAY 1 PERIOD. THE SURFACE CYCLONE SHOULD TRACK INTO IA BY SUNDAY
AFTERNOON AS ASSOCIATED WARM FRONT LIFTS ENEWD ACROSS ERN IA AND NRN
IL. AS THE INTENSIFYING LOW TRACKS ALONG THE WARM FRONT OVER ERN IA
AND NRN IL THROUGH SUNDAY EVENING...ASSOCIATED STRENGTHENING COLD
FRONT SHOULD SWEEP ESEWD FROM THE CNTRL PLAINS TO THE LOWER OH RIVER
VALLEY THROUGH EARLY MONDAY.

...CNTRL PLAINS ACROSS THE MS VALLEY/MIDWEST...
WIDESPREAD DEEP CONVECTION EXPECTED TO BE ONGOING EARLY IN THE DAY
IN AN ARC FROM NEB/IA SEWD TO THE CONFLUENCE OF THE MS/OH RIVERS.
THIS ACTIVITY WILL BE SUSTAINED ALONG A WARM FRONT RETREATING NWD
ACROSS THE REGION AS SURFACE LOW CONSOLIDATES AND STRENGTHENS OVER
ERN NEB. THERE IS GOOD AGREEMENT AMONG A VARIETY OF NCEP MODEL
GUIDANCE THAT THIS CONVECTION...PRIMARILY ELEVATED IN NATURE WITH
SOME POTENTIAL FOR HAIL...WILL LIFT ENEWD ACROSS THE MS VALLEY
THROUGH THE AFTERNOON.

RAIN-COOLED AIR AND CLOUD COVER ASSOCIATED WITH THE MORNING
CONVECTION WILL ACT TO REINFORCE THE WARM FRONT EXPECTED TO EXTEND
EWD FROM THE SURFACE LOW NEAR IA. WARM SECTOR AIRMASS IS LIKELY TO
BECOME INCREASINGLY UNSTABLE THROUGH THE AFTERNOON AS STRONG
DYNAMICS AND COOLER TEMPERATURES ALOFT SPREAD EAST WITH THE
MID/UPPER LEVEL IMPULSE. IN ADDITION TO POTENTIAL FOR RELATIVELY
LOW-TOPPED STORMS FORMING WITHIN THE MID LEVEL VORTEX ACROSS ERN NEB
AND KS...INCREASINGLY DIFFLUENT MID LEVEL FLOW WILL SPREAD ACROSS
THE WARM SECTOR FROM MO INTO IA AND NRN IL. GIVEN CAPE VALUES
INCREASING TO OVER 1000 J/KG NEAR THE SURFACE LOW AND WARM
FRONT...LARGE SCALE FORCING IS EXPECTED TO RESULT IN RAPID
THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON. OVERALL PATTERN AS
CURRENTLY FORECAST BY NAM AND GFS STRONGLY SUGGESTS AN ENHANCED
POTENTIAL FOR LONG-TRACK SUPERCELLS FORMING ACROSS SRN IA/NRN MO AND
THEN MOVING ACROSS THE MS RIVER FROM AFTERNOON INTO EARLY EVENING.
FORECAST STORM RELATIVE SHEAR AND POTENTIALLY LOW LFC NEAR THE WARM
FRONT AND SURFACE LOW...FROM SERN IA INTO NRN IL...APPEAR SUPPORTIVE
OF STRONG TORNADOES IN THIS AREA. VERY LARGE HAIL WILL ALSO BE
POSSIBLE FROM MUCH OF THE ACTIVITY AND CELLS MAY MERGE THROUGH THE
EVENING HOURS...FORMING INTO A FAST MOVING BAND OF CONVECTION ON THE
NOSE OF MID LEVEL JET STREAK. ATTENDANT THREAT OF DAMAGING WINDS
COULD THEN SPREAD EAST ACROSS PARTS OF IL AND IND...AND PERHAPS AS
FAR AS SRN MI AND ERN OH THROUGH EARLY MONDAY AS INTENSIFYING
SURFACE LOW TRACKS INTO LOWER MI. IT IS POSSIBLE THAT PARTS OF THIS
REGION MAY BE UPGRADED TO HIGHER PROBABILITIES AND PERHAPS EVEN A
HIGH RISK IN LATER OUTLOOKS AS OVERALL SEVERE WEATHER SCENARIO
BECOMES CLEARER.

...OZARKS TO LOWER OH/MS VALLEYS AND TN VALLEY...
A MORE COMPLICATED FORECAST SCENARIO EXISTS ACROSS SRN PORTIONS OF
THE HIGH-PROBABILITY SLIGHT RISK AREA. SOME CONVECTION MAY BE
ONGOING EARLY IN THE PERIOD WITHIN WEAKLY UNSTABLE WARM CONVEYOR
BELT FROM NERN TX TO SERN MO/WRN TN. DEGREE OF DESTABILIZATION
WITHIN THIS CORRIDOR WILL DEPEND ON HOW RAPIDLY THIS EARLY ACTIVITY
DISSIPATES. EXPECT THAT FORCING AND INSTABILITY WILL GRADUALLY
INCREASE THROUGH LATE AFTERNOON AND THAT STORMS MAY TAKE SOME TIME
TO BECOME SURFACE-BASED GIVEN POTENTIAL FOR GREATER INHIBITION.
EVENTUALLY...AND PERHAPS NOT UNTIL EVENING...STRONGER STORMS SHOULD
DEVELOP IN A BAND FROM AR EWD ACROSS THE MS RIVER VALLEY AS LARGE
SCALE FORCING/PRE-FRONTAL TROUGH SPREAD EAST INTO THE REGION. SHEAR
AND INSTABILITY CURRENTLY APPEAR FAVORABLE FOR A FEW INTENSE
STORMS...POSSIBLY SUPERCELLS...WITHIN THIS BAND OF CONVECTION.
INCREASINGLY STRONG MID LEVEL FLOW AND MID LEVEL DRY INTRUSION
THROUGH LATE SUNDAY NIGHT ALSO SUGGEST THE DEVELOPMENT OF A SQUALL
LINE WITH OCCASIONAL DAMAGING WINDS MOVING EAST ACROSS THE TN
VALLEY...AND PERHAPS AS FAR EAST AS THE APPALACHIANS... THROUGH
MONDAY MORNING.

..CARBIN.. 04/01/2006