SPC AC 180729
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT FRI MAR 18 2011
VALID 201200Z - 211200Z
...SYNOPSIS...
MODELS SUGGEST THAT A SIGNIFICANT SHORT WAVE IMPULSE...LIFTING
THROUGH THE NORTHERN ROCKIES REGION LATE SATURDAY NIGHT INTO EARLY
SUNDAY...WILL TURN EASTWARD WITHIN A GENERALLY CONFLUENT REGIME
ACROSS THE NORTHERN PLAINS DURING THE DAY SUNDAY. THIS FEATURE MAY
CONTRIBUTE TO THE DEVELOPMENT OF A MODEST FRONTAL WAVE FROM THE
NORTH CENTRAL PLAINS THROUGH THE GREAT LAKES REGION BY LATE SUNDAY
NIGHT...WHILE FLATTENING THE CREST OF THE UPPER RIDGE AXIS CENTERED
NEAR THE MISSISSIPPI VALLEY. HOWEVER...A MUCH MORE
SIGNIFICANT...AMPLIFIED UPPER TROUGH IS PROGGED TO GRADUALLY MIGRATE
INLAND ACROSS THE CALIFORNIA COAST...AS THE UPSTREAM PATTERN ACROSS
THE MID LATITUDE PACIFIC BEGINS TO BECOME MORE ZONAL. AS THIS
OCCURS...UPPER RIDGING PROBABLY WILL MAINTAIN STRENGTH
DOWNSTREAM....ACROSS MUCH OF THE SOUTHERN INTO CENTRAL
PLAINS...WHILE ALSO BEGINNING TO BUILD TO THE IMMEDIATE LEE OF THE
ROCKIES.
HIGHEST THUNDERSTORM PROBABILITIES SUNDAY ARE EXPECTED TO REMAIN
FOCUSED WITHIN A LOWER/MID TROPOSPHERIC WARM ADVECTION REGIME
GRADUALLY DEVELOPING NORTHEAST OF THE MIDDLE MISSISSIPPI VALLEY...
WITH ADDITIONAL STORM DEVELOPMENT PROBABLE ALONG A REMNANT FRONTAL
ZONE FROM THE LOWER OHIO VALLEY SOUTHWARD INTO THE EASTERN GULF
COAST AND FLORIDA PENINSULA. HOWEVER...CONDITIONS MOST CONDUCIVE TO
SEVERE STORM DEVELOPMENT ARE EXPECTED TO REMAIN CONFINED TO PORTIONS
OF THE PLAINS INTO UPPER PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY.
THIS IS WHERE MID-LEVEL LAPSE RATES WILL REMAIN STEEP AND LOW-LEVEL
MOISTURE SUFFICIENT TO SUPPORT MODERATE CAPE IN THE PRESENCE OF
STRONG DEEP LAYER SHEAR...BUT INHIBITION TOO STRONG/LARGE-SCALE
ASCENT TOO WEAK TO SUPPORT APPRECIABLE THUNDERSTORM PROBABILITIES.
ADDITIONALLY...CONSIDERABLE VARIABILITY EXISTS AMONG MODEL DATA
CONCERNING LOW-LEVEL FOCUS FOR STORM INITIATION. CURRENTLY...IT
SEEMS MOST PROBABLE THAT A DRY LINE SETTING UP ACROSS NORTH CENTRAL
OKLAHOMA THROUGH NORTHEAST KANSAS/NORTHWEST MISSOURI COULD BECOME A
FOCUS FOR ISOLATED SUPERCELLS LATE SUNDAY AFTERNOON OR EVENING.
ADDITIONAL ACTIVITY IS POSSIBLE NEAR THE DEVELOPING FRONTAL WAVE
ACROSS IOWA LATER SUNDAY EVENING.
..KERR.. 03/18/2011
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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