[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 300523
SWODY2
SPC AC 300522

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1222 AM CDT WED AUG 30 2006

VALID 311200Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THU AFTN AND EVE ACROSS
PARTS OF THE CNTRL HIGH PLAINS....

VARIABILITY STILL EXISTS AMONG THE MODELS WITH REGARD TO THE
SPECIFICS OF THE EVOLUTION OF THE LARGE-SCALE UPPER FLOW PATTERN
DURING THIS FORECAST PERIOD.  IN GENERAL...THOUGH...A MORE
AMPLIFIED...AND LESS PROGRESSIVE/BLOCKED REGIME IS FORECAST TO
CONTINUE TO DEVELOP.  A WEAK CLOSED LOW IN THE SOUTHERN BRANCH OF
THE POLAR WESTERLIES IS PROGGED TO BECOME CUT-OFF OVER THE LOWER
OHIO VALLEY BY THURSDAY...WITH A PERTURBATION...EMANATING FROM THE
TROPICS...LIFTING OUT OF THE NORTHWESTERN GULF OF MEXICO AROUND ITS
SOUTHERN PERIPHERY.  TO THE SOUTHEAST OF THE LOW...AN INCREASINGLY
SHEARED ERNESTO IS PROGGED TO ACCELERATE FROM SOUTH ATLANTIC COASTAL
AREAS THROUGH MUCH OF THE EASTERN CAROLINAS BY 12Z FRIDAY.

UPSTREAM...MODELS SUGGEST A SUBTROPICAL HIGH CENTER WILL EXPAND ONCE
AGAIN ACROSS THE NORTHERN MEXICAN PLATEAU.  BUT...THIS WILL BE
TEMPERED TO THE NORTH BY THE CONTINUING SLOW EASTWARD MIGRATION OF
AN AMPLIFIED POLAR TROUGH...AND EMBEDDED SHORT WAVES...EASTWARD
INTO/THROUGH THE CENTRAL CANADIAN PRAIRIES AND NORTHERN U.S. PLAINS.


...SOUTHEAST...
CONSIDERABLE UNCERTAINTIES REMAIN CONCERNING TORNADO POTENTIAL WITH
ERNESTO.  LOW-LEVEL CIRCULATION CENTER MAY NOT MAKE LANDFALL ACROSS
COASTAL EASTERN SOUTH CAROLINA UNTIL NEAR OR SHORTLY AFTER DARK
THURSDAY EVENING.  A BRIEF PERIOD OF SOMEWHAT ENHANCED RISK OF AN
ISOLATED TORNADO OR TWO COULD EXIST IN FAVORABLE LOW-LEVEL
CONVERGENCE AND SHEAR...MAINLY ALONG COASTAL AREAS TO ITS NORTHEAST.
 HOWEVER...SLIGHT BOUNDARY LAYER COOLING AFTER DARK... AS ERNESTO
CONTINUES INLAND...MAY ULTIMATELY MITIGATE THREAT.

...CENTRAL HIGH PLAINS...
ALTHOUGH A RETURN FLOW OF GULF MOISTURE IS NOT LIKELY...MODELS
INDICATE MOISTENING WILL OCCUR IN LEE SURFACE TROUGH NEAR THE
KANSAS/COLORADO BORDER.  SURFACE DEW POINTS NEAR 60F APPEAR
LIKELY...AND THIS SHOULD BE SUFFICIENT FOR MODERATE DESTABILIZATION
AS LAPSE RATES STEEPEN WITH DAYTIME HEATING...ALONG WITH AT LEAST
WEAK MID-LEVEL COOLING.  BOUNDARY LAYER CAPE ON THE ORDER OF 2000
J/KG IS ANTICIPATED BY LATE THURSDAY AFTERNOON...WHEN FORCING NEAR
INTERSECTION OF COLD FRONT AND SURFACE TROUGH/WEAK DRY LINE IS
EXPECTED TO ELIMINATED CAPPING ASSOCIATED WITH ELEVATED MIXED LAYER.
 THIS SEEMS MOST PROBABLE ACROSS NORTHEAST COLORADO OR NORTHWEST
KANSAS...WHERE WEAK BUT VEERING WINDS WITH HEIGHT FROM LOWER TO
MID-LEVELS...BENEATH MODERATE WESTERLY HIGH LEVEL FLOW...SHOULD BY
SUFFICIENT FOR ISOLATED SUPERCELLS.

FORCING ASSOCIATED WITH DIFLUENT/DIVERGENT UPPER FLOW FIELD BETWEEN
BASE OF POLAR TROUGH AND CREST OF SUBTROPICAL RIDGE SHOULD ENHANCE
DEVELOPMENT.  AND...ONE OR MORE SMALL CONVECTIVE CLUSTERS COULD
EVOLVE THROUGH EARLY THURSDAY EVENING...PROPAGATING SOUTHWARD ACROSS
THE CENTRAL HIGH PLAINS...ALONG INSTABILITY AXIS NEAR LEE SURFACE
TROUGH.

..KERR.. 08/30/2006