Mar 4, 2015 1300 UTC Day 1 Convective Outlook
Updated: Wed Mar 4 12:39:30 UTC 2015 (20150304 1300Z Day 1 shapefile | 20150304 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150304 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20150304 1300 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20150304 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Large Hail Graphic
20150304 1300 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 041239

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0639 AM CST WED MAR 04 2015

   VALID 041300Z - 051200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   ISOLATED THUNDERSTORMS MAY OCCUR FROM THE SOUTHERN ROCKIES AND
   SOUTHERN PLAINS TO THE TENNESSEE VALLEY AREA.

   ...SYNOPSIS...
   MAIN FEATURE OF MID/UPPER-LEVEL SYNOPTIC-SCALE PATTERN THIS PERIOD
   WILL BE TROUGHING FROM ERN CANADA TO NWRN MEX...TRAVERSED BY SEVERAL
   SHORTWAVE PERTURBATIONS.  IN NRN STREAM...500-MB VORTICITY FIELD
   ACCOMPANYING SHORTWAVE TROUGH NOW OVER DAKOTAS/MN IS EXPECTED TO
   BECOME VERY STRETCHED/ELONGATED FROM MAINE TO LOWER MI BY 12Z.  SWRN
   PART OF THAT PLUME WILL MERGE WITH INITIALLY SEPARATE PERTURBATION
   NOW OVER SK/MT...AND FCST TO MOVE SEWD ACROSS NRN/CENTRAL PLAINS
   THROUGH PERIOD.  SHORTWAVE TROUGH NOW OVER NRN GULF OF CA AND
   CENTRAL BAJA IS FCST TO WEAKEN CONSIDERABLY AS IT EJECTS NEWD TO
   CHIHUAHUA AND FAR W TX BY 00Z...THEN BECOMING ABSORBED INTO
   PROGRESSIVE/NW-FLOW VORTICITY FIELD OVER OK NEAR END OF PERIOD.  BY
   12Z...PRIMARY TROUGH SHOULD EXTEND FROM LM/WI SWWD ACROSS ERN
   KS...TX PANHANDLE AND SONORA.

   AT SFC...11Z ANALYSIS SHOWED COLD FRONT FROM NRN NY SWWD ACROSS
   NRN/WRN KY...OZARKS...DFW METROPLEX...AND E-CENTRAL NM.  THIS FRONT
   WILL PROCEED SWD/SEWD TO 00Z POSITION NEAR
   IAD...TRI...JAN...LFK...DRT LINE.  BY 12Z FRONT SHOULD REACH NC
   OUTER BANKS...NRN GA...SERN LA...NWRN GULF...AND NERN MEX S OF BRO.

   ...SRN PLAINS TO TN VALLEY...
   BROAD SWATH OF MODEST LOW-LEVEL WAA AND MOISTURE TRANSPORT WILL
   PERSIST THROUGH PERIOD...SUPPORTING EPISODIC PRECIP PLUMES AND
   ISOLATED/EMBEDDED TSTMS MAINLY ALONG AND BEHIND SFC FRONT.  THIS
   REGIME IS EXPECTED TO SHIFT SLOWLY EWD/SEWD BUT BECOME NARROWER
   ALONG NW-SE SHORT AXIS AS DEEPER WEDGE OF POSTFRONTAL COLD AIR
   PENETRATES BENEATH THIS PLUME.  RESULT SHOULD BE NET LATERAL
   SHRINKAGE WITH TIME...ESPECIALLY AFTER 00Z.

   WITH SUBSTANTIAL MID/UPPER-LEVEL LARGE-SCALE FORCING REMAINING
   BEHIND SFC COLD FRONT...EXPECT WARM-SECTOR LAPSE RATES TO REMAIN
   WEAK.  MAIN CONTRIBUTOR TO LOW-LEVEL LIFT FOR CONVECTION WILL BE
   FRONTAL ZONE ITSELF...BOTH AT SFC AND FOR ELEVATED LIFTED PARCELS
   FARTHER NW.  ISOLATED/SHORT-LIVED WARM-SECTOR TSTMS CANNOT BE RULED
   OUT AS WELL OVER PORTIONS LOWER MS VALLEY REGION THIS AFTN INTO
   EVENING...GIVEN POCKETS OF DIURNAL HEATING AMIDST WEAK CINH.  IF ANY
   SUCH CONVECTION OCCURS...FCST SOUNDINGS SUGGEST AROUND 50 KT
   EFFECTIVE SHEAR MAGNITUDES AND CONDITIONAL POTENTIAL FOR A SVR TSTM.
    HOWEVER...
   1. RELATIVELY STABLE LAYERS AROUND 700 AND 500 MB WILL SUBSTANTIALLY
   REDUCE DEEP BUOYANCY...AND
   2. FOCI FOR SUSTAINED PREFRONTAL LIFT OF PARCELS OUT OF BOUNDARY
   LAYER APPEAR TOO WEAK/UNCERTAIN TO DRAW UNCONDITIONAL SVR
   PROBABILITIES ATTM.

   ...SRN ROCKIES AND VICINITY...
   STEEPENING LAPSE RATES...AND RELATED POCKETS OF 100-300 J/KG MUCAPE
   INTO LTG-SUITABLE ICING LAYERS...ARE POSSIBLE TODAY AS EJECTING BAJA
   SHORTWAVE TROUGH AND OVERALL COOLING ALOFT WITH SYNOPTIC TROUGH
   AFFECT PARTS OF THIS AREA.  LACK OF MORE ROBUST LOW-LEVEL THETAE
   SHOULD KEEP TSTMS WEAK...WITH ONLY ISOLATED COVERAGE AND VERY
   SPORADIC INSTEAD OF CONTINUAL OCCURRENCE.

   ..EDWARDS/GLEASON.. 03/04/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z