SPC AC 170544
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1244 AM CDT SAT JUN 17 2006
VALID 181200Z - 191200Z
...NO SVR TSTM AREAS FORECAST...
MODELS INDICATE STRONGER WESTERLIES WILL PERSIST IN A BELT EXTENDING
OUT OF THE NORTHERN PACIFIC...THROUGH THE NORTHWESTERN AND NORTH
CENTRAL U.S....INTO SOUTHEASTERN CANADA THROUGH THIS FORECAST
PERIOD. A COUPLE OF WAVES EMBEDDED WITHIN THIS REGIME ARE PROGGED
TO REMAIN PROGRESSIVE...ONE ADVANCING FROM THE NORTH CENTRAL
CANADIAN/U.S. BORDER AREA INTO THE GREAT LAKES...ANOTHER ADVANCING
INLAND ACROSS THE PACIFIC NORTHWEST INTO THE NORTHERN INTERMOUNTAIN
REGION.
IN ADVANCE OF LATTER FEATURE...AN UPPER RIDGE IS FORECAST TO BUILD
ACROSS THE SOUTHERN U.S./NORTHERN MEXICAN PLATEAU REGION INTO THE
CENTRAL/SOUTHERN PLAINS BY LATE SUNDAY NIGHT. WITH A SHARP UPPER
RIDGE REMAINING STRONG THROUGH MUCH OF THE PERIOD ACROSS THE EASTERN
STATES...SHEARING OF AN UPPER TROUGH TO THE SOUTH OF THE STRONGER
WESTERLIES WILL CONTINUE ACROSS EASTERN PORTIONS OF THE SOUTHERN
PLAINS INTO THE LOWER HALF OF THE MISSISSIPPI VALLEY.
...EAST OF ROCKIES...
CONSIDERABLE UNCERTAINTY EXISTS CONCERNING SEVERE POTENTIAL
SUNDAY/SUNDAY NIGHT. IT WILL REMAIN VERY MOIST FROM THE WESTERN/
CENTRAL GULF STATES NORTHWARD AHEAD OF A PRE-FRONTAL CONFLUENCE INTO
THE LOWER GREAT LAKES REGION. HOWEVER...FLOW FIELDS ARE PROGGED TO
WEAKEN CONSIDERABLY ACROSS THE SOUTH CENTRAL STATES IN RESPONSE TO
EVOLVING UPPER PATTERN. AND...WHERE STRONG LOW/MID-LEVEL FLOW
FIELDS PERSIST AHEAD OF NORTH CENTRAL U.S. UPPER TROUGH...WEAK
LAPSE RATES WILL TEND TO MINIMIZE DESTABILIZATION. THIS WILL
FURTHER BE LIMITED BY EXTENSIVE CLOUD COVER ASSOCIATED WITH A COUPLE
OF DAYS OF WIDESPREAD CONVECTIVE DEVELOPMENT. STABILIZING INFLUENCE
OF SURFACE COLD POOLS GENERATED BY THIS CONVECTION IS ALSO
UNCERTAIN.
IN WAKE OF PRE-FRONTAL CONFLUENT ZONE...PROGGED TO SHIFT ACROSS THE
OHIO VALLEY/LOWER GREAT LAKES REGION DURING THE DAY SUNDAY...
DIFFERENTIAL THERMAL ADVECTION ALONG/JUST AHEAD OF COLD FRONT SEEMS
TO OFFER BEST POTENTIAL/FOCUS FOR VIGOROUS CONVECTIVE DEVELOPMENT.
BY LATE AFTERNOON...THE FRONT IS EXPECTED TO CURVE FROM THE UPPER
GREAT LAKES REGION THROUGH THE NORTH CENTRAL PLAINS. THOUGH
MOISTURE WILL BE LIMITED NEAR THIS FEATURE ...SUFFICIENT
DESTABILIZATION APPEARS LIKELY FOR AT LEAST SCATTERED THUNDERSTORMS.
PERHAPS ENHANCED BY FAVORABLE SHEAR BENEATH SEASONABLY STRONG
CYCLONIC MID-LEVEL FLOW...A FEW STORMS COULD PRODUCE HAIL/GUSTY
WINDS APPROACHING OR BRIEFLY EXCEEDING SEVERE LIMITS. ACTIVITY MAY
SPREAD SOUTHEASTWARD THROUGH LOWER GREAT LAKES AND PARTS OF THE
MIDDLE MISSISSIPPI VALLEY BEFORE DIMINISHING SUNDAY EVENING.
FARTHER SOUTH...POTENTIAL FOR SURFACE HEATING APPEARS MUCH BETTER
FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY...WHERE
70F SURFACE DEW POINTS SHOULD PERSIST. BENEATH LINGERING MID-LEVEL
COOL POCKET...THIS COULD CONTRIBUTE TO A FAVORABLE THERMODYNAMIC
ENVIRONMENT FOR STRONG/LOCALIZED SEVERE STORMS WITH HAIL/GUSTY
WINDS.
...WEST OF ROCKIES...
FORCING/SHEAR ASSOCIATED WITH A 40-50 KT MID-LEVEL JET STREAK IS
EXPECTED TO ENHANCE CONVECTIVE POTENTIAL NEAR LOW/MID-LEVEL
BAROCLINIC ZONE ACROSS PARTS OF EASTERN OREGON/CENTRAL AND SOUTHERN
IDAHO LATE SUNDAY AFTERNOON/EVENING. MOISTURE WILL BE LIMITED...BUT
LAPSE RATES WILL BECOME QUITE STEEP AND SUPPORTIVE OF AT LEAST
WIDELY SCATTERED STORMS WITH POTENTIAL FOR MICROBURSTS.
..KERR.. 06/17/2006
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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