SWODY2
SPC AC 021646
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1146 AM CDT THU OCT 02 2008
VALID 031200Z - 041200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
AN AMPLIFIED LONG WAVE PATTERN WILL EXIST OVER N AMERICA DURING THE
DAY TWO PERIOD. THIS REGIME WILL FEATURE AN INTENSIFYING TROUGH
OVER THE ERN PACIFIC INTO THE WRN U.S. AND CANADA...DOWNSTREAM
RIDGING OVER CNTRL CANADA INTO THE N-CNTRL STATES...AND A WEAKENING
TROUGH OVER ERN CANADA AND THE NERN U.S.
...SRN PLAINS INTO OZARK PLATEAU...
INTENSIFYING LEE TROUGH OVER THE HIGH PLAINS WILL SUPPORT THE NWD
DEVELOPMENT OF A WEAK WARM FRONT THROUGH TX INTO THE RED RIVER
VALLEY. A MODIFIED CP AIR MASS WITH DEWPOINTS IN THE 50S TO LOWER
60S WILL DEVELOP NWD THROUGH ERN TX...ALONG AND S OF THIS BOUNDARY.
THIS PROCESS WILL OCCUR BENEATH THE ERN EDGE OF EML/STEEP MIDLEVEL
LAPSE RATE PLUME ORIGINATING OVER THE SRN ROCKIES WITH ENVIRONMENT
BECOMING MODERATELY UNSTABLE WITH MLCAPE APPROACHING 1000-1500 J/KG.
IN THE ABSENCE OF ANY APPRECIABLE LARGE-SCALE FORCING
MECHANISMS...THERE IS SOME QUESTION AS TO WHETHER CAP WILL BE
OVERCOME ALONG WARM FRONT AND/OR WEAK DRYLINE/TROUGH THROUGH THE
DIURNAL HEATING CYCLE.
THE GREATER LIKELIHOOD FOR TSTM DEVELOPMENT /MAINLY ELEVATED/
APPEARS TO BE LATE FRIDAY NIGHT INTO SATURDAY MORNING OVER ERN OK
INTO THE OZARK PLATEAU AS STRENGTHENING...NOCTURNAL LLJ ENHANCES
WAA/ISENTROPIC ASCENT TO THE N OF RETREATING SURFACE FRONT. SOME
HAIL WILL BE POSSIBLE WITH THE MORE INTENSE STORMS GIVEN MODEST
CLOUD-BEARING SHEAR AND THE STEEP MIDLEVEL LAPSE RATES.
CURRENTLY...THIS THREAT APPEARS TOO MARGINAL TO WARRANT INCLUSION OF
ANY SEVERE PROBABILITIES.
...ROCKIES INTO HIGH PLAINS...
AGEOSTROPHY IN EXIT REGION OF UPPER-LEVEL JET STREAK AND BROADER
HEIGHT FALLS IN ADVANCE OF INTENSIFYING TROUGH WILL RESULT IN A
FAIRLY LARGE AREA OF INCREASED LARGE-SCALE FORCING FOR ASCENT
FRIDAY. THIS COMBINED WITH A STEEP LAPSE RATE ENVIRONMENT AND
OROGRAPHIC FORCING SHOULD RESULT IN WIDELY SCATTERED...DIURNAL TSTM
DEVELOPMENT AS FAR E AS CNTRL HIGH PLAINS INVOF OF LEE TROUGH. SOME
SMALL HAIL AND/OR GUSTY WINDS WILL BE POSSIBLE WITH THE MORE INTENSE
ACTIVITY. HOWEVER...THE LIMITED CONVECTIVE INSTABILITY WILL LIKELY
PRECLUDE A MORE ROBUST SEVERE THREAT.
...CNTRL/SRN FL...
LOW-LEVEL FLOW WILL VEER TO ELY...MAINTAINING A MOIST LOW-LEVEL AIR
MASS ACROSS THE SRN AND CNTRL PENINSULA. WHILE MIDLEVEL LAPSE RATES
WILL REMAIN WEAK...BOUNDARY LAYER DEWPOINTS IN THE 60S COUPLED WITH
DAYTIME HEATING WILL RESULT IN THE DEVELOPMENT OF WEAK TO
POTENTIALLY MODERATE CONVECTIVE INSTABILITY THROUGH THE DIURNAL
HEATING CYCLE. AS SUCH...SCATTERED TSTMS WILL BE POSSIBLE ALONG
DEVELOPING SEA BREEZE CIRCULATIONS WHERE LOW-LEVEL CONVERGENCE IS
MAXIMIZED. GUSTY WINDS MAY ACCOMPANY SOME OF THE STRONGER
STORMS...BUT NO SEVERE WEATHER IS EXPECTED.
..MEAD.. 10/02/2008
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