SPC AC 090601
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0101 AM CDT WED APR 09 2008
VALID 101200Z - 111200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF AR/FAR NORTHEAST
TX/NORTHERN LA/MUCH OF MO INTO SOUTHERN IL/WESTERN KY/WESTERN
TN/NORTHWEST MS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE ARKLATEX/MISSISSIPPI
VALLEY/OHIO VALLEY...
...ARKLATEX/MID SOUTH/OZARKS INTO THE MIDDLE MISSISSIPPI/OHIO
VALLEYS...
CONFIDENCE CONTINUES TO INCREASE THAT A SEVERE WEATHER OUTBREAK MAY
OCCUR ACROSS THE ARKLATEX/MID SOUTH/OZARKS INTO PORTIONS OF THE
MIDDLE MISSISSIPPI/OHIO VALLEYS. THIS INCLUDES DAMAGING WINDS/LARGE
HAIL AND TORNADOES...SOME OF WHICH MAY BE STRONG/LONG-TRACKED.
LATEST 00Z BASED MODEL GUIDANCE CONTINUES TO GRADUALLY CONVERGE ON
THE DETAILS OF THE DEEPENING/PROGRESSIVELY CLOSED CYCLONE ACROSS THE
NATIONS MID SECTION ON THURSDAY. WHILE THE MID/UPPER TROUGH SHIFTS
NORTHEASTWARD ACROSS THE CENTRAL PLAINS...THE CORRESPONDING SURFACE
LOW IS EXPECTED TO DEEPEN ACROSS THE CENTRAL PLAINS/CORNBELT. AS
GULF OF MEXICO TRAJECTORIES CONTINUE TO IMPROVE AHEAD OF THIS
SYSTEM...RELATIVELY RICH BOUNDARY LAYER MOISTURE WILL ADVECT
NORTHEASTWARD ACROSS THE REGION...WITH 60-65F SURFACE DEWPOINTS
LIKELY TO BECOME ESTABLISHED AS FAR NORTH AS NORTHERN MO/CENTRAL
IL/CENTRAL IND THURSDAY AFTERNOON/EVENING.
A MULTI-MODE SEVERE DAY IS LIKELY ON THURSDAY IN AND NEAR THE
MODERATE RISK AREA. STRONG/SEVERE STORMS WILL BE ONGOING THURSDAY
MORNING ACROSS PORTIONS OF CENTRAL/EASTERN OK AND NORTH TX INTO
ADJACENT PORTIONS OF MO/KS/NORTHERN AR. AHEAD OF THIS ACTIVITY AND
THE EAST-ADVANCING SYNOPTIC COLD FRONT...AMIDST A DESTABILIZING
BOUNDARY LAYER WITH PROGRESSIVELY WEAK CINH IN THE WARM
SECTOR...SURFACE BASED QUASI-DISCRETE SUPERCELLULAR DEVELOPMENT IS
LIKELY DURING THE AFTERNOON/EARLY EVENING ACROSS THE
ARKLATEX/OZARKS/MID SOUTH REGION. WITH A WARM FRONT EXPECTED TO LIFT
NORTHWARD FROM OK/AR INTO THE OHIO VALLEY DURING THE DAY...RAPID
DESTABILIZATION IS LIKELY TO OCCUR DURING THE AFTERNOON/EVENING
NORTHWARD ACROSS MO/IL/IND. GIVEN THE POTENTIAL IMPACTS OF EARLY DAY
STORMS...THE REALIZATION OF APPRECIABLE INSTABILITY/TIMING THEREOF
IS SOMEWHAT MORE QUESTIONABLE WITH NORTH EXTENT ACROSS MO/IL/IND.
HOWEVER...VERY STRONG KINEMATICS/FLOW FIELDS WILL LEAD TO A MARKED
SEVERE RISK EVEN WHERE MODEST MLCAPE MATERIALIZES...I.E. 500-1000
J/KG...IN THE WAKE OF THE WARM FRONT. ASIDE FOR THE QUASI-DISCRETE
DEVELOPMENT IN THE WARM SECTOR...EVENTUAL EVOLUTION OF A BROKEN
SQUALL LINE APPEARS LIKELY ALONG THE COLD FRONT BY LATE
AFTERNOON/EVENING. THIS SHOULD GRADUALLY OVERTAKE LEADING-LINE
ACTIVITY FROM WEST TO EAST ACROSS THE REGION THROUGH THE EVENING.
OVERALL...VERY STRONG SOUTH TO SOUTHWESTERLY WINDS IN THE LOW TO MID
TROPOSPHERE...WITH 80-110 KT AT 500 MB AND 50-70 KT AT 850 MB...WILL
FAVOR BOTH FAST MOVING SUPERCELLS AND THE EVENTUAL EVOLUTION OF
QUASI-LINEAR BOW ECHOES ACROSS A BROAD PORTION OF THE ARKLATEX/MID
SOUTH REGION NORTHWARD INTO THE MIDDLE MISSISSIPPI/OHIO VALLEYS.
BOTH WITH QUASI-DISCRETE SUPERCELLS OR LEWP EVOLUTIONS...A HIGH
HELICITY ENVIRONMENT /WITH 250-450 MS/S2 0-1 KM SRH IN MUCH OF THE
MODERATE RISK AREA/ AND MOIST BOUNDARY LAYER WILL SUPPORT AN
APPRECIABLE RISK FOR TORNADOES...SOME OF WHICH COULD BE STRONG/LONG
TRACKED. OTHERWISE...WIDESPREAD DAMAGING WINDS AND LARGE HAIL ARE
LIKELY.
AS DETAILS REGARDING EARLY DAY STORMS AND CONVECTIVE MODE BECOME
BETTER RESOLVED WITH TIME...AN UPGRADE TO A CATEGORICAL HIGH RISK IS
POSSIBLE IN SUBSEQUENT OUTLOOKS.
..GUYER.. 04/09/2008
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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