More on Storms for later today

Here are the latest discussions and risk assessment for the area later this afternoon.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CDT FRI JUN 13 2008

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS PARTS OF THE S
CNTRL PLAINS AND MID MS VLY...THRU MUCH OF THE OHIO VLY AND SRN
GREAT LAKES REGION....

...SYNOPSIS...
MODELS INDICATE THAT THE CLOSED LOW NEAR THE CENTRAL CANADIAN/U.S.
BORDER WILL TAKE A MORE NORTHEASTWARD TURN...TOWARD HUDSON BAY...
DURING THIS FORECAST PERIOD. THIS APPEARS LIKELY TO OCCUR IN
RESPONSE TO A SIGNIFICANT IMPULSE PIVOTING AROUND ITS IMMEDIATE
SOUTHERN AND EASTERN PERIPHERY...WHILE ANOTHER UPSTREAM IMPULSE DIGS
TO THE LEE OF THE CANADIAN ROCKIES.

WHILE STRONGEST MID/UPPER FLOW IS PROGGED TO BEGIN SHIFTING TO THE
NORTHEAST OF THE UPPER GREAT LAKES EARLY IN THE DAY...SEASONABLY
MODERATE TO STRONG CYCLONIC MID-LEVEL FLOW IS FORECAST TO PERSIST
ACROSS THE NORTHERN/CENTRAL PLAINS THROUGH THE UPPER HALF OF THE
MISSISSIPPI VALLEY...THE OHIO VALLEY AND GREAT LAKES REGION. WITHIN
THIS REGIME...AND A DISTINCT BELT OF STRONGER FLOW TO THE SOUTH OF
THE MAIN CLOSED LOW...A SIGNIFICANT LOW AMPLITUDE IMPULSE IS IN THE
PROCESS OF TURNING EAST OF THE CENTRAL ROCKIES THROUGH THE CENTRAL
PLAINS. AND...MUCH OF MODEL GUIDANCE INDICATES THAT THIS FEATURE
WILL CONTINUE EAST NORTHEASTWARD THROUGH THE DAY...CONTRIBUTING TO
MID-LEVEL HEIGHT FALLS ACROSS THE OHIO VALLEY AND LOWER GREAT LAKES
REGION BY THIS EVENING...AND PARTS OF THE TENNESSEE VALLEY/NORTHERN
AND CENTRAL APPALACHIANS BY 12Z SATURDAY.

WHILE SHARP UPPER RIDGING PERSISTS NEAR THE ATLANTIC SEABOARD...
MODELS INDICATE THAT SUBTROPICAL RIDGING WILL SLOWLY BUILD NORTHWARD
THROUGH THE SOUTHWESTERN STATES...WHILE REMAINING STRONG ACROSS THE
CENTRAL/EASTERN GULF STATES...BEFORE BECOMING SUPPRESSED EAST OF THE
LOWER MISSISSIPPI VALLEY LATER TONIGHT.

...S CNTRL PLAINS THROUGH THE OHIO VALLEY/LWR GREAT LAKES...
THE SURFACE FRONT ASSOCIATED WITH NORTH CENTRAL STATES UPPER TROUGH
WILL MAKE ONLY SLOW PROGRESS EAST/SOUTHEASTWARD INTO THE REGION
TODAY. THE BOUNDARY WILL BE PRECEDED /AND PROBABLY MASKED/ BY
COMPOSITE CONVECTIVELY GENERATED OUTFLOW BOUNDARIES WHICH...IN
CONJUNCTION WITH AT LEAST A COUPLE OF MESOSCALE CONVECTIVE
VORTICES...LIKELY WILL PROVIDE THE FOCUS FOR NEW CONVECTIVE
DEVELOPMENT BY THIS AFTERNOON. THE BOUNDARY LAYER ALONG/AHEAD OF
THE SURFACE BOUNDARIES REMAINS SEASONABLY MOIST... AND WILL AGAIN
BECOME MODERATE TO STRONGLY UNSTABLE WITH DAYTIME HEATING.

IN THE PRESENCE OF MIXED LAYER CAPE AT OR ABOVE 2000 J/KG...AND AT
LEAST A MODERATELY SHEARED 30-50 KT WESTERLY DEEP LAYER MEAN
FLOW...ORGANIZED STORM CLUSTERS ARE EXPECTED TO EVOLVE/INTENSIFY IN
THE PEAK AFTERNOON HEATING. THIS SHOULD BE AIDED BY LARGE SCALE
FORCING ASSOCIATED WITH THE IMPULSE EMANATING FROM THE CENTRAL
ROCKIES...AND PROGGED TO SPREAD EAST OF THE MIDDLE MISSISSIPPI
VALLEY BY THE 13/18-21Z TIME FRAME...THROUGH THE LOWER GREAT
LAKES/UPPER OHIO VALLEY BY 14/03-06Z.

HODOGRAPHS MAY BE SUFFICIENT FOR SUPERCELLS WITH POTENTIAL FOR
TORNADOES/HAIL IN INITIAL STORMS...BUT SWATHS OF DAMAGING WINDS ARE
EXPECTED TO BE A MORE PROMINENT THREAT...PARTICULARLY AS COLD POOLS
STRENGTHEN/CONSOLIDATE ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES
REGION LATE THIS AFTERNOON AND EVENING.

..KERR/GRAMS.. 06/13/2008