SPC AC 021741
DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1141 AM CST FRI JAN 02 2015
VALID 031200Z - 041200Z
...THERE IS A SLGT RISK OF SVR TSTMS SATURDAY INTO SATURDAY NIGHT
ACROSS PARTS OF SOUTHEAST LOUISIANA...AND MUCH OF CENTRAL/EASTERN
MISSISSIPPI INTO WESTERN ALABAMA...
...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT RISK AREA
ACROSS THE LOWER MISSISSIPPI VALLEY INTO PARTS OF THE TENNESSEE
VALLEY...
CORRECTED FOR TYPOS
...SUMMARY...
SEVERE STORMS ARE POSSIBLE SATURDAY INTO SATURDAY NIGHT EAST OF THE
LOWER MISSISSIPPI VALLEY. STRONGEST STORMS MAY BE CAPABLE OF
PRODUCING DAMAGING WIND GUSTS AND PERHAPS A COUPLE OF TORNADOES.
...SYNOPSIS...
STRONGER BELTS OF WESTERLIES REMAIN SPLIT AROUND A BLOCKING UPPER
HIGH CENTER OVER ALASKA...EMERGING FROM THE MID-LATITUDE PACIFIC AND
THE ARCTIC LATITUDES...BEFORE CONVERGING OVER NORTH AMERICA...TO THE
NORTHWEST OF AN EXPANDING SUBTROPICAL HIGH CENTER NEAR THE BAHAMAS.
WHILE FURTHER STRENGTHENING OF THE SUBTROPICAL HIGH CENTER APPEARS
PROBABLE THROUGH THIS FORECAST PERIOD...A CLOSED LOW WITHIN ONE BELT
OF WESTERLIES OVER THE SOUTHWEST IS FORECAST TO FINALLY ACCELERATE
NORTHEAST OF THE SOUTHERN ROCKIES...AS A SHORT WAVE TROUGH WITHIN
ANOTHER STREAM DIGS ACROSS THE NORTHERN ROCKIES THROUGH THE SOUTH
CENTRAL PLAINS. AS YET ANOTHER SIGNIFICANT SHORT WAVE TROUGH DIGS
ACROSS THE CANADIAN PRAIRIES INTO THE CENTRAL CANADIAN/U.S. BORDER
AREA...MODELS CONTINUE TO INDICATE THE CONSOLIDATION/EVOLUTION OF
AMPLIFIED LARGER SCALE UPPER TROUGHING CENTERED OVER THE MISSISSIPPI
VALLEY BY EARLY SUNDAY. THIS IS EXPECTED TO BE ACCOMPANIED BY
STRONG SURFACE CYCLOGENESIS ACROSS THE OHIO VALLEY INTO THE LOWER
GREAT LAKES REGION SATURDAY NIGHT...FOLLOWED BY ANOTHER SIGNIFICANT
COLD INTRUSION TO THE LEE OF ROCKIES. WHILE THE FRONT TRAILING
SOUTHWARD FROM THE DEVELOPING CYCLONE ON THE LEADING EDGE OF THIS
INTRUSION MAY SURGE EAST OF THE MID/LOWER MISSISSIPPI VALLEY BY
EARLY SATURDAY EVENING...MODELS SUGGEST THAT COLD AIR WILL REMAIN
DAMMED TO THE SOUTH AND EAST OF THE APPALACHIANS.
...MID/LOWER MS VALLEY INTO THE APPALACHIANS...
MODELS INDICATE THE NORTHEASTWARD ACCELERATION OF THE LEAD IMPULSE
WILL BE ACCOMPANIED BY CONSIDERABLE STRENGTHENING OF SOUTHWESTERLY
MID/UPPER FLOW FROM THE SOUTHERN PLAINS RED RIVER VALLEY INTO THE
LOWER GREAT LAKES REGION. IT APPEARS THAT THIS PROBABLY WILL
INCLUDE A 500 MB JET CORE INCREASING IN EXCESS OF 110 KT.
HOWEVER...STRONGEST MID/UPPER FORCING FOR UPWARD VERTICAL MOTION
SHOULD REMAIN WELL INLAND OF COASTAL AREAS...AND MAY REMAIN MOSTLY
DISPLACED TO THE WEST AND NORTH OF THE WARM SECTOR OF THE INITIALLY
MODEST SURFACE FRONTAL WAVE EXPECTED TO TRACK ACROSS UPPER PORTIONS
OF THE LOWER MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY SATURDAY
AFTERNOON AND EVENING.
AS A SOUTHERLY PRE-COLD FRONTAL RETURN FLOW CONTINUES OFF THE
WESTERN GULF OF MEXICO...SUBSTANTIVE BOUNDARY LAYER MOISTENING DOES
APPEAR POSSIBLE WITHIN A LEAST A NARROW PRE-FRONTAL
CORRIDOR...PERHAPS AS FAR NORTH AS WESTERN INTO MIDDLE TENNESSEE BY
SATURDAY EVENING. DESPITE THE LACK OF SUFFICIENT DIFFERENTIAL
THERMAL ADVECTION TO YIELD SUBSTANTIVE STEEPENING OF MID-LEVEL LAPSE
RATES...THE DEVELOPMENT OF MIXED LAYER CAPE ON THE ORDER OF 500 J/KG
IS GENERALLY EXPECTED. THIS SHOULD CONTRIBUTE TO A FAVORABLE
ENVIRONMENT FOR ORGANIZED SEVERE STORM DEVELOPMENT...INCLUDING
SUPERCELLS...AS MODELS INDICATE 40-50+ KT SOUTHERLY 850 MB FLOW WILL
EXTEND SOUTHWARD THROUGH THE WARM SECTOR...SUPPORTING
SIZABLE...CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS.
STRONGEST THUNDERSTORM DEVELOPMENT SEEMS MOST PROBABLE INLAND OF
COASTAL AREAS...WITH THE PRIMARY SEVERE WEATHER POTENTIAL DEVELOPING
WITHIN A WINDOW COINCIDING WITH STRONG SURFACE LOW DEEPENING OVER
THE OHIO VALLEY...BEFORE BOUNDARY LAYER INSTABILITY WANES WITH THE
LOSS OF DAYTIME HEATING AND FRONTAL PASSAGE SATURDAY EVENING.
..KERR.. 01/02/2015
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0700Z
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