SWODY1
SPC AC 191012
DAY 1 CONVECTIVE OUTLOOK RESENT 1
NWS STORM PREDICTION CENTER NORMAN OK
0512 AM CDT MON MAY 19 2008
VALID 191200Z - 201200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
PRIMARY FEATURE OF INTEREST WILL BE SHORT WAVE TROUGH /CURRENTLY
OVER SASKATCHEWAN/ WHICH WILL INTENSIFY WHILE TRANSLATING SEWD
THROUGH THE NRN PLAINS AND MID MS VALLEY...BEFORE TURNING MORE EWD
ACROSS OH VALLEY BY TUESDAY MORNING. A WEAKER IMPULSE WILL PRECEED
THE MAIN SHORT WAVE TROUGH SEWD THROUGH THE MID MS AND OH
VALLEYS...AND EVENTUALLY TO THE MID ATLANTIC COAST.
IN THE LOW LEVELS...SURFACE CYCLONE OVER ERN KS AT THE START OF THE
FORECAST PERIOD IS EXPECTED TO DEVELOP ESEWD ALONG RETREATING WARM
FRONT INTO SERN MO BY LATE AFTERNOON...AND THEN EWD ACROSS KY INTO
VA TONIGHT. MEANWHILE...A TRAILING COLD FRONT WILL SAG SWD THROUGH
THE CNTRL PLAINS AND OZARK PLATEAU...EVENTUALLY INTO THE SRN PLAINS
AND LOWER MS VALLEY BY THE END OF THE FORECAST PERIOD.
...LOWER OH/TN VALLEYS...
LARGE-SCALE PATTERN EVOLUTION WILL ALLOW FOR THE EWD ADVECTION OF
WARM EML AIR MASS INTO THE MS VALLEY FROM THE CNTRL/SRN HIGH PLAINS.
LOW-LEVEL MOISTURE WILL INCREASE THROUGH THE DAY BENEATH THE EML
PLUME WITH DEWPOINTS RISING THROUGH THE 50S WITH MLCAPES APPROACHING
1000-1500 J/KG THIS AFTERNOON OVER THE SRN LOW PLAINS INTO OZARK
PLATEAU. HOWEVER...FORECAST SOUNDINGS INDICATE THAT THE CAP WILL
REMAIN QUITE STRONG...LIKELY INHIBITING SURFACE-BASED...DIURNAL
STORM DEVELOPMENT.
ELEVATED TSTMS WILL BECOME INCREASINGLY LIKELY BETWEEN 20/00-03Z
AHEAD OF SURFACE LOW AND N OF WARM FRONT ALONG THE OH RIVER AS
LARGE-SCALE HEIGHT FALLS ASSOCIATED WITH PRIMARY SHORT WAVE TROUGH
BEGIN TO OVERSPREAD THE REGION. CLOUD BEARING SHEAR WILL BE
RELATIVELY STRONG...HOWEVER IT APPEARS THAT ELEVATED INSTABILITY
WILL REMAIN SOMEWHAT MARGINAL WITH MUCAPES GENERALLY LESS THAN 1000
J/KG. SOME SEVERE HAIL AND STRONG WIND GUSTS WILL BE POSSIBLE WITH
THE MORE INTENSE STORMS MOVING/DEVELOPING EWD/SEWD ACROSS PORTIONS
OF KY/TN TONIGHT.
UNCERTAINTIES EXIST WITH RESPECT TO: 1) WHETHER ANY SURFACE-BASED
STORM DEVELOPMENT WILL OCCUR ALONG THE FRONT...AND 2) HOW FAR W/SW
STORMS WILL DEVELOP INTO THE STRONG CAP IN PLACE OVER THE OZARK
PLATEAU. AS A RESULT...ONLY LOW PROBABILITIES WILL BE INCLUDED IN
THIS FORECAST. SHOULD LATER DATA INDICATE A HIGHER LIKLIHOOD OF
SURFACE-BASED STORMS WITHIN THE AXIS OF STRONGER INSTABILITY...
HIGHER PROBABILITIES AND A CATEGORICAL SLIGHT RISK MAY HAVE TO BE
REINTRODUCED.
...ERN SD/SWRN MN/NWRN IA...
NW-SE ORIENTED LOW-LEVEL BAROCLINIC ZONE IS EXPECTED TO FOCUS
LOW-TOPPED TSTMS THIS AFTERNOON WITHIN A STEEP LAPSE RATE
ENVIRONMENT. WHILE CONVECTIVE INSTABILITY WILL REMAIN MARGINAL
/SBCAPES AOB 300 J PER KG/...THE STEEP LAPSE RATES AND COOL
THERMODYNAMIC PROFILES MAY SUPPORT A FEW STRONGER STORMS CAPABLE OF
SOME HAIL. LOCALLY STRONG WIND GUSTS ARE ALSO POSSIBLE GIVEN THE
RELATIVELY STRONG...UNIDIRECTIONAL WIND PROFILES.
..MEAD/CROSBIE.. 05/19/2008
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