SPC AC 220712
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0212 AM CDT THU JUN 22 2006
VALID 241200Z - 251200Z
...NO SVR TSTM AREAS FORECAST...
CONSIDERABLE VARIABILITY EXISTS AMONG THE MODELS CONCERNING THE
DETAILS OF SMALLER SCALE FEATURES WITHIN THE DEVELOPING UPPER FLOW
PATTERN DURING THIS FORECAST PERIOD. HOWEVER...GUIDANCE IS IN
GENERAL AGREEMENT...INDICATING THAT STRONG UPPER RIDGING WILL
CONTINUE ACROSS MUCH OF THE WESTERN U.S...AND THAT A POLAR LOW WILL
CONTINUE GRADUALLY LIFTING OUT OF THE EASTERN CANADIAN PROVINCES.
WEAK UPPER TROUGHING WILL LINGER ACROSS THE EASTERN HALF OF THE
NATION...WITH ANOTHER SOUTHERN STREAM SHORT WAVE TROUGH DIGGING INTO
THE UPPER MISSISSIPPI VALLEY. BUT...STRONGER WESTERLIES WILL
GENERALLY REMAIN NORTH OF THE CANADIAN/U.S. BORDER.
...MISSISSIPPI VALLEY TO ATLANTIC COAST...
SOUTH OF WEAKENING SURFACE FRONT ACROSS PARTS OF THE UPPER OHIO
VALLEY/NORTH CENTRAL APPALACHIANS INTO SOUTHERN NEW ENGLAND...AND
EAST OF WEAK REMNANT CONVECTIVELY GENERATED BOUNDARY ACROSS THE
TENNESSEE/LOWER MISSISSIPPI VALLEY...LOW-LEVELS WILL REMAIN
SEASONABLY MOIST. WITH AT LEAST WEAK TO MODERATE INSOLATION...
MIXED LAYER CAPE ON THE ORDER OF 1500-2000 J/KG IS EXPECTED BY
SATURDAY AFTERNOON...SUPPORTING SCATTERED VIGOROUS CONVECTIVE
DEVELOPMENT. A LINGERING MID-LEVEL SHEAR AXIS APPEARS LIKELY TO
PROVIDE THE FOCUS FOR THE MOST WIDESPREAD LATE AFTERNOON/EVENING
THUNDERSTORM ACTIVITY. TONGUE OF HIGHER PRECIPITABLE WATER CONTENT
AIR ALONG/SOUTHEAST OF THIS FEATURE...ALONG WITH STEEPER LOW-LEVEL
LAPSE RATES...MAY BE FAVORABLE FOR HEAVY DOWNPOURS... ACCOMPANIED BY
A FEW LOCALIZED DOWNBURSTS.
...PLAINS...
FORCING ASSOCIATED WITH THE SOUTHERN BRANCH SHORT WAVE TROUGH COULD
SUPPORT WIDELY SCATTERED STORMS ACROSS PARTS OF THE NORTHERN PLAINS
SATURDAY AFTERNOON. A COUPLE OF THESE COULD BRIEFLY BECOME
STRONG/SEVERE IN AN ENVIRONMENT WITH STEEP LAPSE RATES. BETTER
LOW-LEVEL MOISTURE BY THIS TIME...HOWEVER...MAY ONLY RETURN AS FAR
NORTH AS THE CENTRAL HIGH PLAINS. THIS IS WHERE MODELS SUGGEST
FORCING FOR CONVECTIVE DEVELOPMENT MAY BECOME ENHANCED BY A WEAK
SUBTROPICAL IMPULSE CIRCULATING AROUND WESTERN HIGH CENTER. BOTH
NAM/GFS ARE RATHER SIMILAR WITH CONVECTIVE SIGNAL SOUTHWARD
ALONG/JUST EAST OF THE KANSAS/COLORADO BORDER LATE SATURDAY
AFTERNOON AND EVENING. DESPITE THIS SIMILARITY...GIVEN EXPECTED
LACK OF MORE EXTREME INSTABILITY...AND GENERAL LOW PREDICTABILITY OF
THESE TYPE OF FEATURES...CONFIDENCE IS TOO LOW TO DEPICT A SLIGHT
RISK AREA AT THIS TIME.
..KERR.. 06/22/2006
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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