SWODY1
SPC AC 011956
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT SAT SEP 01 2007
VALID 012000Z - 021200Z
..NO SVR TSTM AREAS FORECAST...
..ERN ND/NWRN MN...
AFTERNOON WATER VAPOR IMAGERY SHOWS LEAD SHORT WAVE TROUGH
TRANSLATING ENEWD INTO WRN MANITOBA WITH WEAKER UPSTREAM IMPULSE
MOVING INTO WRN SASKATCHEWAN. IN THE LOW-LEVELS...SURFACE PRESSURE
TROUGH WAS SITUATED OVER THE CNTRL DAKOTAS AS OF 19Z WITH TRAILING
COLD FRONT SLOWLY PUSHING SWD THROUGH NRN MT. AS MENTIONED IN
PREVIOUS OUTLOOK...AIR MASS REMAINS STRONGLY CAPPED BY WELL-DEFINED
ELEVATED MIXED LAYER WITH SURFACE TEMPERATURES OF 95-100 F NECESSARY
TO BREAK CAP. CLOUD DEBRIS REMNANT FROM NOCTURNAL ELEVATED TSTMS
HAS SLOWED DAYTIME HEATING ACROSS MUCH OF PRE-FRONTAL WARM
SECTOR...THOUGH LOCALLY STRONGER HEATING IS OCCURRING INVOF TROUGH
OVER CNTRL ND WHERE TEMPERATURES HAVE WARMED TO AROUND 90 F.
WATER VAPOR IMAGERY AND SHORT TERM MODEL GUIDANCE SUGGEST THAT THE
STRONGER LARGE-SCALE FORCING FOR ASCENT ATTENDANT TO LEAD IMPULSE IS
QUICKLY LIFTING NEWD INTO MANITOBA AND WRN ONTARIO. AS SUCH...ANY
DIURNAL...SURFACE-BASED STORM DEVELOPMENT WILL BE LARGELY DEPENDENT
ON CONVERGENCE ALONG BOUNDARY AND DIABATIC HEATING. SHOULD STORMS
DEVELOP AND BECOME SUSTAINED...THE PRESENCE OF STEEP LAPSE
RATES...SBCAPES OF 1000-1500 J/KG AND 30-35 KT OF EFFECTIVE BULK
SHEAR INDICATE POTENTIAL FOR ORGANIZED STORMS CAPABLE OF DAMAGING
WINDS AND HAIL. LOW WIND/HAIL PROBABILITIES WILL BE MAINTAINED
GIVEN THE UNCERTAINTIES IN STORM INITIATION AND COVERAGE.
..CNTRL HIGH PLAINS...
VISIBLE SATELLITE SHOWS GROWING CUMULUS ALONG SRN EXTENSION OF
PRESSURE TROUGH FROM LIC AND AKO NNEWD INTO WRN NEB. RUC OBJECTIVE
SOUNDING AND PLAN VIEW DATA INDICATE THAT AIR MASS HAS BECOME
MODERATELY UNSTABLE OWING TO STRONG DIABATIC HEATING WITH SBCAPES OF
1000-1500 J/KG. REGIONAL PROFILERS SHOW THAT VERTICAL SHEAR REMAINS
RELATIVELY WEAK ACROSS INSTABILITY AXIS...HOWEVER THE PRESENCE OF
RATHER STEEP LOW TO MID-LEVEL LAPSE RATES MAY SUPPORT A FEW STRONGER
STORMS CAPABLE OF LOCALLY DAMAGING WINDS AND SOME HAIL.
..AZ/NM...
MORE WIDESPREAD TSTM DEVELOPMENT HAS OCCURRED SO FAR TODAY ALONG WRN
FRINGE OF MID-LEVEL MOIST PLUME FROM E-CNTRL AZ EWD INTO NM WITH
MORE ISOLATED DEVELOPMENT OCCURRING WITHIN DRIER MID-LEVEL
ENVIRONMENT OVER NRN AND CNTRL AZ /PER WATER VAPOR IMAGERY/. 12Z
SOUNDINGS FROM THE PHOENIX AND TUCSON AREAS SHOWED INVERTED-V
PROFILES WHICH HAVE LIKELY BECOME MORE PRONOUNCED AS TEMPERATURES
HAVE WARMED THROUGH THE 90S TO 100-105 F. DESPITE THE RATHER WEAK
TROPOSPHERIC WIND FIELDS...SOME POTENTIAL FOR LOCALLY STRONG WET
MICROBURSTS WILL EXIST AS ONGOING STORMS MOVE/DEVELOP SWWD INTO
LOWER ELEVATIONS WHERE BOUNDARY LAYER IS HOT...DEEPLY MIXED AND
SUPPORTIVE OF STRONG EVAPORATIONAL COOLING IN THE SUB CLOUD LAYER.
.MEAD.. 09/01/2007
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