Post by Randy - Brandon, MS on Feb 14, 2009 4:12:24 GMT -6
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0223 AM CST MON FEB 16 2009
VALID 181200Z - 191200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE SERN
STATES...
...SYNOPSIS...
MODEL CONSENSUS IS THAT SRN BRANCH UPPER JET WILL ADVANCE INTO THE
LOWER MS...TN AND OH VALLEYS WED WHERE IT WILL INTENSIFY AS IT
MERGES WITH AMPLIFYING NRN STREAM. SUBSEQUENT CONSOLIDATION AND
AMPLIFICATION OF THE TROUGH WILL CONTINUE OVER THE ERN STATES WED
NIGHT. SURFACE LOW TRACK WILL REMAIN TIED TO STRONGER FORCING WITHIN
UPPER JET EXIT REGION. THIS FEATURE WILL LIFT NE THROUGH THE OH
VALLEY DURING THE DAY. TRAILING COLD FRONT WILL SWEEP EWD THROUGH
THE OH VALLEY AND SERN STATES.
...SERN STATES...
DEGREE OF SEVERE WEATHER THREAT REMAINS CONTINGENT ON AMOUNT OF
INSTABILITY THAT CAN DEVELOP IN WARM SECTOR. DEEPER GULF FRONTAL
INTRUSION WILL OCCUR MONDAY OVER THE CNTRL AND ERN GULF AS AREA OF
SURFACE HIGH PRESSURE ADVANCES THROUGH THE SERN STATES. EFFECTS OF
THE COLD ADVECTION WILL BE MUCH LESS OVER A PORTION OF THE SWRN GULF
WHERE DEWPOINTS WILL REMAIN IN THE UPPER 60S. BY WEDNESDAY AN AXIS
OF PARTIALLY MODIFIED GULF AIR WILL ADVECT NWD THROUGH THE LOWER MS
VALLEY AND A PORTION OF THE SERN STATES ALONG A STRONG SWLY LOW
LEVEL JET ASSOCIATED WITH THE EWD MIGRATING CYCLONE. ELEVATED STORMS
WILL BE ONGOING OVER A PORTION OF THE SERN U.S. AND OH VALLEY WITHIN
ZONE OF STRONG ISENTROPIC ASCENT. THE STORMS WILL SHIFT EAST DURING
THE DAY...BUT IN THEIR WAKE...WIDESPREAD CLOUDS WILL LIKELY PERSIST
OVER MUCH OF WARM SECTOR WHICH WILL TEND TO LIMIT INSTABILITY.
CLUSTERS OF STORMS MAY REDEVELOP ALONG AND EAST OF ADVANCING FRONT
WITHIN ZONE OF HEIGHT FALLS AND LOW LEVEL CONFLUENT FLOW REGIME FROM
THE LOWER MS VALLEY INTO PARTS OF THE SERN STATES. ACTIVITY WILL BE
EMBEDDED WITHIN VERY STRONG KINEMATIC PROFILES WHICH WOULD SUPPORT
AN ORGANIZED SEVERE THREAT INCLUDING POTENTIAL FOR SUPERCELLS AND
BOWING STRUCTURES WITH ANY SURFACE BASED DEEP CONVECTION. POTENTIAL
FOR A MARGINAL THERMODYNAMIC ENVIRONMENT COULD STILL POSE A LIMITING
FACTOR FOR A HIGHER END SEVERE EVENT.
...SRN PORTIONS OF THE OH VALLEY...
COLDER AIR ALOFT AND PLUME OF STEEPER MID LEVEL LAPSE RATES WILL
ATTEND THE UPPER JET EXIT REGION THROUGH SRN PARTS OF THE OH
VALLEY...AND THIS COULD COMPENSATE FOR MORE LIMITED LOW LEVEL
MOISTURE IN THIS AREA. STRONG AGEOSTROPHIC FORCING ATTENDING THE
UPPER JET WILL LIKELY CONTRIBUTE TO REDEVELOPMENT OF CONVECTION
SOUTH AND EAST OF SURFACE LOW TRACK. PRIMARY UNCERTAINTY AT THIS
TIME IS HOW MUCH THE BOUNDARY LAYER CAN DESTABILIZE IN WAKE OF
MORNING CONVECTION GIVEN POTENTIAL FOR LOW CLOUDS TO PERSIST. STRONG
VERTICAL SHEAR AND STEEP LAPSE RATES IN THIS REGION WOULD SUPPORT
ORGANIZED SEVERE STORMS. HOWEVER...DUE TO THE CONDITIONAL NATURE OF
THE THREAT ONLY 5% SEVERE PROBABILITIES WILL BE ADDED AT THIS
TIME...BUT AN CATEGORICAL RISK MIGHT BE NEEDED FOR A PORTION OF THIS
REGION IN LATER OUTLOOKS.
) up around 500 J/KG just won't cut it. There should be plenty of moisture around here, and directional shear looks good.
