Saturday, February 2, 2008

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 021732
SWODY2
SPC AC 021729

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CST SAT FEB 02 2008

VALID 031200Z - 041200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
A BROAD LONGWAVE TROUGH CURRENTLY CENTERED ACROSS THE CONUS IS
EXPECTED TO UNDERGO CHANGE THROUGH THE DAY 2 FORECAST PERIOD AS A
SHORT WAVE TROUGH...NOW LOCATED IN THE NERN PACIFIC /VICINITY OF 50N
140W/...DIGS SEWD CARVING OUT A TROUGH IN THE WEST. MEANWHILE...A
LEAD SHORT WAVE TROUGH ENCOUNTERING HEIGHT RISES DOWNSTREAM OF
AMPLIFYING WRN TROUGH IS EXPECTED TO WEAKEN ON SUNDAY AS IT TRACKS
NEWD FROM THE SRN HIGH PLAINS TO THE GREAT LAKES REGION. A SERIES
OF WEAKER MID LEVEL IMPULSES WILL TRACK NEWD FROM NRN MEXICO THROUGH
LOWER MS VALLEY TO MID ATLANTIC REGION WITHIN SWLY FLOW REGIME.

SURFACE CYCLOGENESIS IE EXPECTED IN THE CENTRAL HIGH PLAINS BY 12Z
MONDAY. REMNANT SURFACE BOUNDARY EXTENDING FROM THE OH VALLEY TO
THE SRN PLAINS AT 12Z SUNDAY IS EXPECTED TO RETREAT NWD AS A WARM
FRONT AND SHOULD EXTEND ENEWD FROM THE LOW THROUGH KS TO OH.

..LOWER MS VALLEY/NORTH CENTRAL GULF COAST TO MO AND OH VALLEY...
INCREASING SSWLY LOW LEVEL WINDS FROM THE SRN PLAINS/LOWER MS VALLEY
INTO THE OH VALLEY DURING DAY 2 WILL ALLOW WRN GULF MOISTURE TO
RETURN NWD TO THE ARKLATEX AND PART OF LOWER MS VALLEY. ASCENT
ATTENDANT TO LOW LEVEL WAA AND A WEAK SRN STREAM IMPULSE TRAVERSING
THIS REGION SHOULD AID IN SHOWERS/EMBEDDED TSTM DEVELOPMENT. MODELS
SUGGEST INSTABILITY WILL BE GREATER ACROSS E TX...BUT STRENGTH OF
CAPPING INVERSION SHOULD LIMIT LIKELIHOOD FOR DEEP CONVECTION.
ALTHOUGH FORECAST HODOGRAPHS SUGGEST A NONZERO POTENTIAL FOR STORM
ROTATION WITH ANY SURFACE BASED STORMS FROM LA INTO SWRN MS...WEAKER
INSTABILITY WITH EWD EXTENT INTO THIS REGION SUGGESTS TOO MUCH OF A
NEGATING FACTOR TO INCLUDE ANY SEVERE PROBABILITIES AT THIS TIME.

FARTHER N...ASCENT WITH SRN HIGH PLAINS TROUGH SHOULD BE SUFFICIENT
FOR ELEVATED TSTM DEVELOPMENT FROM THE OZARKS SUNDAY AFTERNOON AND
SPREADING NEWD INTO THE MID OH VALLEY REGION SUNDAY NIGHT. ALTHOUGH
DEEP-LAYER SHEAR WITHIN THE CLOUD-BEARING LAYER WOULD BE SUFFICIENT
FOR ROTATION...IT APPEARS THAT WEAK INSTABILITY SHOULD LIMIT ANY
HAIL TO SUB-SEVERE SIZE.

..PARTS OF CENTRAL/SRN CA TO GREAT BASIN/FOUR CORNERS...
STEEPENING LAPSE RATE ENVIRONMENT SHOULD SUPPORT LOW TOPPED
CONVECTION...IN THE WAKE OF THE PRIMARY BAROCLINIC ZONE EXPECTED TO
SPREAD ACROSS SAN JOAQUIN VALLEY DURING THE MID-LATE MORNING AS
PACIFIC TROUGH AMPLIFIES SEWD INTO GREAT BASIN/LOWER CO RIVER
VALLEY. SOME OF THIS ACTIVITY MAY BECOME DEEP ENOUGH FOR CHARGE
SEPARATION/ LIGHTNING PRODUCTION. RESIDUAL COOL LOW LEVEL AIR MASS
ACROSS THIS REGION TODAY WILL LIMIT GREATER INSTABILITY FROM
DEVELOPING ON DAY 2. TRACK OF SYSTEM ALOFT TO THE N/NE OF THIS PART
OF CA SUGGESTS TERRAIN INFLUENCE OF LOW LEVEL WINDS /I.E. BACKED TO
SELY/ MAY NOT OCCUR AND THUS PRECLUDE FAVORABLE LOW AND DEEP LAYER
SHEAR FROM DEVELOPING FOR ORGANIZED STORMS. THUS... WILL NOT
INTRODUCE ANY SEVERE WEATHER PROBABILITIES...BUT WILL EXTEND DAY 2
GENERAL TSTM AREA WWD TO INCLUDE PARTS OF CENTRAL/SRN CA.

FURTHER E...SHOWERS AND SPORADIC LIGHTNING STRIKES CAN BE EXPECTED
AS STEEP LAPSE RATES SPREAD EWD ACROSS NV/AZ TO FOUR CORNERS REGION
IN CONJUNCTION WITH THE MAIN MID-UPPER LEVEL TROUGH.

.PETERS.. 02/02/2008

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