DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 171255
SWODY1
SPC AC 171254

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0754 AM CDT MON MAR 17 2014

VALID 171300Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL/SRN FL
PENINSULA...

...SYNOPSIS...
PROGRESSIVE UPPER-AIR PATTERN WILL FEATURE TWO PRIMARY SHORTWAVE
TROUGHS...WITH THEIR ASSOCIATED PATTERNS ALSO DESCRIBED.

1. LEADING PERTURBATION NOW LOCATED FROM TN VALLEY REGION SWWD OVER
TX COAST AND W-CENTRAL MEX. SWRN LOBE WILL BREAK AWAY AND WEAKEN
SLOWLY...WHILE DRIFTING EWD ACROSS CENTRAL MEX. REMAINDER OF THIS
FEATURE WILL DEAMPLIFY SOMEWHAT AND ASSUME MORE NEUTRAL TILT AS IT
CROSSES NRN GULF AND ADJACENT STATES. BY 12Z...TROUGH SHOULD BE
LOCATED OVER CAROLINAS...COASTAL GA AND NEAR EXTREME NERN FL. WEAK
SFC LOW NOW OVER NRN GA SHOULD DISSIPATE GRADUALLY...WHILE ANOTHER
WEAK LOW OVER NERN GULF MOVES EWD ACROSS N-CENTRAL FL PENINSULA.
LATTER LOW SHOULD STRENGTHEN SUBSTANTIALLY AFTER MOVING OVER ATLC
WATERS...CAUSING TRAILING COLD FRONT NOW OVER N-CENTRAL GULF TO
ACCELERATE SEWD OVER MOST OF FL PENINSULA TONIGHT.

2. UPSTREAM MID-UPPER-LEVEL TROUGH -- NOW EVIDENT IN
MOISTURE-CHANNEL IMAGERY OVER INLAND PAC NW AND NRN CA -- WILL MOVE
ESEWD ACROSS N-CENTRAL ROCKIES TO SD...NEB AND CO BY END OF PERIOD.
SFC CYCLOGENESIS NOW UNDERWAY OVER NERN MT WILL SHIFT SEWD
TODAY...LEADING TO PRONOUNCED LOW OVER SD BADLANDS REGION BY 00Z AND
NERN NEB BY 12Z. STG DEEP-LAYER FORCING WILL OCCUR INVOF SFC
CYCLONE...JUXTAPOSING LOW LEVEL WAA AND INCREASING DCVA ALOFT TO
YIELD STEEP LAPSE RATES AND MRGL BUOYANCY. MAIN LIMITING FACTOR FOR
THUNDER COVERAGE WILL BE LACK OF RICHER MOISTURE.

...FL...
BKN BAND OF TSTMS HAS BEEN CREEPING EWD ACROSS NERN GULF ALL
NIGHT...AND WILL MOVE OVER MORE OF WRN/CENTRAL FL THROUGH REMAINDER
MORNING. SVR POTENTIAL WILL INCREASE AS CONVECTION ENCOUNTERS
PROGRESSIVELY MORE MOIST/UNSTABLE BOUNDARY LAYER PER MODIFIED 12Z
TBW RAOB...AMIDST FAVORABLE LOW-LEVEL AND DEEP SHEAR FOR SVR. MAIN
CONCERN WILL BE DAMAGING GUSTS...ESPECIALLY FROM BOW/LEWP
FORMATIONS. ACCOMPANYING MESO/MISOCIRCULATIONS AND EMBEDDED
SUPERCELLS ALSO MAY POSE TORNADO RISK. REF SPC MESOSCALE DISCUSSION
196 FOR MORE DETAILED NEAR-TERM INSIGHTS.

SVR POTENTIAL IS EXPECTED TO SHIFT ACROSS ERN THROUGH SWRN FL THIS
AFTN...THEN PROGRESS GRADUALLY SEWD DOWN PENINSULA OVERNIGHT.
TYPICALLY STABILIZING EFFECTS OF DIABATIC/NOCTURNAL SFC COOLING WILL
BE MITIGATED CONSIDERABLY BY PRESENCE OF INCREASINGLY RICH
BOUNDARY-LAYER MOISTURE...WITH SFC DEW POINTS COMMONLY UPPER 60S TO
LOW 70S F. THIS SHOULD HELP TO MAINTAIN SFC-BASED EFFECTIVE-INFLOW
PARCELS...OFFSETTING WEAK MID-UPPER LEVEL LAPSE RATES TO KEEP
1000-1500 J/KG MLCAPE AND MINIMAL CINH.

MEANWHILE...PASSAGE OF TROUGH NW-N OF AREA WILL MAINTAIN
SUFFICIENTLY TIGHT HEIGHT GRADIENT ALOFT TO SUPPORT FAVORABLE DEEP
SHEAR...WHILE SFC COLD FRONT AND RELATED LIFT APPROACHES PREVIOUSLY
PREFRONTAL TSTM BAND. ISALLOBARIC FORCING RELATED TO ATLC
CYCLOGENESIS WILL VEER SFC FLOW SOMEWHAT OVER ERN/SRN
PENINSULA...HOWEVER INTENSIFYING LLJ SHOULD OFFSET THAT IN TERMS OF
MAINTAINING FAVORABLY LARGE HODOGRAPHS. FCST SOUNDINGS SUGGEST
40-50 KT EFFECTIVE SHEAR MAGNITUDES WILL REMAIN COMMON AFTER 00Z
OVER PRECONVECTIVE WARM SECTOR...COMBINING WITH AFOREMENTIONED
BUOYANCY TO MAINTAIN SVR RISK NOCTURNALLY.

..EDWARDS/MOSIER.. 03/17/2014

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.