Friday, March 29, 2013

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 291552
SWODY1
SPC AC 291551

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1051 AM CDT FRI MAR 29 2013

VALID 291630Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN PLNS...

...SYNOPSIS...
SPLIT FLOW PATTERN WILL BECOME MORE PROMINENT ACROSS THE LWR 48 THIS
PERIOD AS REX-TYPE BLOCK EVOLVES OVER THE NE PACIFIC AND THE
DOWNSTREAM NRN BRANCH OF FLOW BECOMES MORE DOMINANT ACROSS THE NRN
PLNS...THE MID MS VLY...AND CNTRL/SRN APPALACHIANS. SATELLITE AND
UPR AIR DATA SHOW A SRN STREAM IMPULSE NOW ENTERING WRN NM THAT
SHOULD CONTINUE E INTO W TX THIS EVE AND TO THE ARKLATEX EARLY SAT.
THIS FEATURE...IN CONJUNCTION WITH SFC HEATING AND MODEST BUT
PERSISTENT LOW-LVL MOISTURE RETURN ACROSS THE SRN PLNS...WILL
SUPPORT SOME RISK FOR STRONG TO SVR STORMS OVER PARTS OF THE REGION
LATER TODAY INTO TNGT.

...SRN PLNS TODAY INTO TNGT...
WAA AND MOISTURE TRANSPORT ATOP FAIRLY STOUT EML CAP LIKELY WILL
CONTINUE TO SUPPORT AREAS OF HIGH-BASED AND ELEVATED STORMS ABOVE
THE CAP INTO TNGT...BOTH IN DEVELOPING WARM SECTOR OVER OK AND NW
TX...AND ATOP DEVELOPING SFC WARM/STNRY FRONT ACROSS THE SRN/CNTRL
OZARKS. SOME OF THIS ACTIVITY MAY YIELD MARGINALLY SVR HAIL. BUT
MOST OF THE STORMS SHOULD REMAIN ROOTED ABOVE THE CAP. COUPLED WITH
RELATIVELY MODEST SHEAR...DEGREE OF ELEVATED CAPE SHOULD REMAIN TOO
LIMITED TO POSE AN APPRECIABLE RISK FOR SVR WEATHER.

A SOMEWHAT GREATER RISK FOR SVR STORMS...MAINLY WITH HAIL BUT ALSO
POSSIBLY WITH LOCALLY DMGG WIND...MAY EVOLVE LATER THIS AFTN INTO
TNGT OVER PARTS OF WRN AND NW TX AND ADJACENT WRN/SRN OK. IN THIS
REGION...FAVORABLY-TIMED APPROACH OF NM UPR IMPULSE WITH MAX SFC
HEATING MAY YIELD A SUFFICIENT COMBINATION OF DESTABILIZATION AND
ASCENT TO PROMOTE STRONG STORM DEVELOPMENT ON WRN FRINGE OF LOW-LVL
MOISTURE RETURN.

WHILE WLY DEEP SHEAR ACROSS REGION WILL REMAIN SEASONABLY MODEST
/30-35 KTS/...UNIDIRECTIONAL NATURE OF CLOUD-LAYER FLOW AND PRESENCE
OF DEEP EML/STEEP MID-LVL LAPSE RATES COULD YIELD NUMEROUS STORMS
WITH SVR HAIL AS MUCAPE INCREASES TO NEAR 1500 J/KG. CONTINUED EWD
MOTION OF UPR IMPULSE AND EXPECTED AMALGAMATION OF STORM-GENERATED
COLD POOLS MAY LEAD TO THE DEVELOPMENT OF ONE OR TWO ESE-MOVING
STORM CLUSTERS OVER NW TX AND OK. THIS ACTIVITY COULD PRODUCE
ADDITIONAL SVR HAIL AND LOCALLY DMGG WIND INTO LATER TNGT...BEFORE
DIURNAL COOLING WEAKENS UPDRAFT STRENGTH.

...CNTRL HIGH PLNS LATE AFTN/EARLY EVE...
A MORE ISOLD SVR RISK MAY EXTEND NWD INTO THE CNTRL HIGH PLNS OF
WRN/CNTRL NEB AND NW KS LATER TODAY...WHERE STRONG SFC HEATING AND
WEAK CONVERGENCE WILL EXIST ALONG LEE TROUGH. BOUNDARY LAYER
MOISTURE WILL REMAIN QUITE LIMITED...BUT SOME DEGREE OF ASCENT WILL
BE PROVIDED BY NRN STREAM DISTURBANCE NOW MOVING ESE ACROSS WY. ANY
SVR THREAT /MARGINALLY SVR HAIL/ SHOULD DIMINISH WITH LOSS OF
DAYTIME HEATING.

..CORFIDI/ROGERS.. 03/29/2013

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