SWODY2
SPC AC 270543
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1243 AM CDT TUE MAY 27 2008
VALID 281200Z - 291200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
LARGE TROUGH OVER THE ERN PACIFIC/WRN CONUS IS FORECAST TO BEGIN
MAKING SOME EWD PROGRESS ACROSS THE ROCKIES DURING THE LATTER HALF
OF THIS PERIOD. THIS COMBINED WITH AN EWD SHIFT IN THE ERN NOAM
TROUGH SHOULD RESULT IN SOME AMPLIFICATION OF THE CENTRAL U.S. RIDGE
THROUGH THE PERIOD.
AT THE SURFACE...A BAROCLINIC ZONE EXTENDING WWD ACROSS THE SERN
QUARTER OF THE CONUS SHOULD MAKE SLOW SWD PROGRESS...WHILE RELATIVE
LOW PRESSURE SHOULD PREVAIL OVER THE WEST IN CONJUNCTION WITH THE
APPROACHING UPPER TROUGH.
...PARTS OF THE PAC NW EWD INTO MT...
MARGINAL INSTABILITY COMBINED WITH THE PASSAGE OF SEVERAL
SMALL-SCALE VORTICITY MAXIMA WITHIN DIFFLUENT/SSWLY MID-LEVEL FLOW
FIELD AHEAD OF THE LARGER-SCALE TROUGH OFF THE W COAST SHOULD YIELD
FAIRLY WIDESPREAD CONVECTIVE DEVELOPMENT ACROSS THE NWRN CONUS THIS
PERIOD. COMBINATION OF AMPLE SHEAR FOR A FEW STRONGER/ORGANIZED
UPDRAFTS AND THE LIKELIHOOD FOR SUB-CLOUD EVAPORATION SUGGESTS THAT
LOCALLY GUSTY/DAMAGING WINDS WILL BE POSSIBLE ACROSS A LARGE
AREA...FROM ERN WA/ERN ORE/NERN CA NEWD INTO WRN MT. GREATEST
THREAT IS EXPECTED DURING THE AFTERNOON/EARLY EVENING...FOLLOWED BY
A GRADUAL DECREASE IN STORM COVERAGE/INTENSITY.
...NRN HIGH PLAINS...
WHILE 500 TO 1000 J/KG MIXED-LAYER CAPE SHOULD EVOLVE OVER THE NRN
HIGH PLAINS DURING THE AFTERNOON...CAPPING INVERSION SHOULD INHIBIT
CONVECTIVE DEVELOPMENT THROUGH MOST OF THE AFTERNOON. PERSISTENT
HEATING/MIXING MAY EVENTUALLY WEAKEN THE CAP SUFFICIENTLY IN A FEW
AREAS TO PERMIT THE DEVELOPMENT OF ISOLATED STORMS -- AND WITH
MODERATE/VEERING FLOW WITH HEIGHT...SHEAR WOULD SUPPORT
ORGANIZATION/ROTATION WITH ANY DEVELOPING UPDRAFT. THUS...WILL
INTRODUCE CONDITIONAL 5% SEVERE PROBABILITY FROM PARTS OF ERN MT SWD
INTO CO ALONG THE FRONT RANGE.
...ERN NM INTO ADJACENT PORTIONS OF TX...
SELY LOW-LEVEL FLOW MAY PROVIDE AMPLE UPSLOPE COMPONENT TO DRIVE THE
DEVELOPMENT OF ISOLATED/HIGH-BASED STORMS OVER ERN NM...AS MARGINAL
AIRMASS DESTABILIZATION OCCURS THROUGH THE AFTERNOON.
WITH MODEST/WSWLY MID-LEVEL FLOW ATOP LOW-LEVEL SELYS...DEGREE OF
VEERING/SHEAR MAY SUPPORT SOME UPDRAFT ORGANIZATION.
THEREFORE...WILL MAINTAIN LOW PROBABILITY/5% SEVERE THREAT ACROSS
PARTS OF ERN NM AND ADJACENT PARTS OF WRN TX.
...ARKLATEX REGION EWD INTO THE TN VALLEY/NRN GULF COAST STATES...
MOIST BOUNDARY LAYER COMBINED WITH SOME HEATING SHOULD YIELD AREAS
OF MODERATE INSTABILITY NEAR AND AHEAD OF SWD-MOVING FRONT.
CONVECTION SHOULD BE ONGOING INVOF THE FRONT EARLY...AND SHOULD
CONTINUE/INCREASE THROUGH THE AFTERNOON AS AIRMASS DESTABILIZES.
WHILE DEEP-LAYER WIND FIELD SHOULD REMAIN FAIRLY WEAK...DEGREE OF
MOISTURE/INSTABILITY SUGGESTS A THREAT FOR A FEW STRONGER/PULSE-TYPE
STORMS CAPABLE OF PRODUCING MARGINAL HAIL AND LOCALLY GUSTY WINDS.
..GOSS.. 05/27/2008
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