Mar 28, 2009 0600 UTC Day 1 Convective Outlook
Updated: Sat Mar 28 05:41:17 UTC 2009
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20090328 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20090328 1200 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20090328 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20090328 1200 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 280538
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1238 AM CDT SAT MAR 28 2009
   
   VALID 281200Z - 291200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
   OH/TN VLYS INTO THE SERN STATES...
   
   ...SYNOPSIS...
   STACKED UPR LOW OVER OK/N TX AT THE START OF THE PERIOD WILL SLOWLY
   TRANSLATE EWD INTO THE LWR OH/TN VLYS AND DEEP SOUTH THROUGH
   SATURDAY NIGHT.  ATTENDANT SFC LOW WILL SHIFT FROM NEAR MEMPHIS NEWD
   INTO THE CNTRL GRTLKS REGION BY 12Z SUNDAY.  TRAILING CDFNT WILL
   SWEEP EWD TO THE S OF THE LOW FROM THE MS VLY EARLY SATURDAY TO THE
   APLCNS AND NRN FL BY SUNDAY MORNING.  AHEAD OF THE FRONT...A WARM
   FRONT WILL DEVELOP NWD INTO CNTRL/NRN GA...THE CNTRL CAROLINAS...AND
   INTO TIDEWATER VA/MD.
   
   ...SERN STATES INTO THE CAROLINAS/VA...
   ANOTHER COMPLEX CONVECTIVE FCST WITH GREAT UNCERTAINTY WILL EXIST
   FOR SATURDAY.  CNTRL GULF COAST MCS THAT IGNITED ALONG INCREASING
   MOIST SLY LLVL FLOW ON FRIDAY EVENING WILL BE ONGOING AT 12Z ACROSS
   ERN MS...AL AND THE FL PNHDL.  AHEAD OF THIS SYSTEM...GULF BOUNDARY
   LAYER THAT WAS SHUNTED SWD ON FRIDAY...IS EXPECTED TO SURGE NWD INTO
   AT LEAST SRN/CNTRL GA AND EVENTUALLY THE CNTRL CAROLINAS BY SATURDAY
   AFTN/EVE.  ALTHOUGH THERE IS SOME QUESTION ON HOW MUCH HEATING CAN
   BE REALIZED...MLCAPES SHOULD RANGE FROM 1000-1500 J/KG FROM SERN AL
   NEWD INTO THE CAROLINAS.  A LIKELY MCV...BORNE FROM THE MCS...WILL
   MOVE ENEWD INTO THIS INSTABILITY AXIS...SUPPORTING A CONTINUED SVR
   THREAT DOWNSTREAM INTO THE OVERNIGHT AS FAR NE AS VA.
   
   SUFFICIENT VERTICAL SHEAR WILL EXIST FOR ORGANIZED STORMS ACROSS THE
   REGION OWING TO SLY H85 FLOW OF 50 KTS VEERING TO WSWLY AT H5 IN
   EXCESS OF 60 KTS.  SUPERCELL MODES WILL LIKELY TRANSITION INTO
   BOWS/LEWPS GIVING DMGG WINDS AND LARGE HAIL.  HIGHEST TORNADO RISK
   WILL ACCOMPANY DISCRETE CELLS THAT CAN INTERACT WITH THE RETREATING
   WRMFNT...NAMELY FROM SERN AL...CNTRL/SRN GA NEWD INTO THE CNTRL
   CAROLINAS.
   
   ...TN/OH VLYS...
   A SEPARATE AREA OF SVR POTENTIAL WILL LIKELY DEVELOP ACROSS PORTIONS
   OF THE TN/OH VLYS DURING THE AFTN/EVE.  STRONGEST DCVA WILL
   TRANSLATE NEWD AWAY FROM THE RICH GULF MOISTURE SOURCE FARTHER SE.
   BUT...LINGERING 50S SFC DEW POINTS ARCING BACK ALONG THE CDFNT/SFC
   LOW INTO THE LWR OH VLY BENEATH STEEP MID-TROPOSPHERIC LAPSE RATES
   WILL CONTRIBUTE TO MLCAPES OF A FEW HUNDRED J PER KG.  EXPECT THAT
   SCTD TSTMS WILL DEVELOP AND SLOWLY INTENSIFY FROM PARTS OF WRN
   KY/MIDDLE TN AMIDST STRONG VERTICAL SHEAR.  A FEW LOW-TOPPED
   SUPERCELLS MAY EVOLVE AND ADVANCE INTO PARTS OF SRN IND...SWRN OH
   AND KY/ERN TN DURING THE EVENING.  LARGE HAIL AND ISOLD DMGG WIND
   GUSTS WILL BE POSSIBLE.  TORNADOES CANNOT BE RULED OUT...ESPECIALLY
   WITH MORE SUSTAINED STORMS AND CLOSE TO THE SFC LOW TRACK.  SVR
   THREATS WILL DIMINISH WITH NE EXTENT AND AFTER SUNSET.
   
   ..RACY/HURLBUT.. 03/28/2009
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z