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    Day 2 Outlook >
Sep 3, 2015 0600 UTC Day 1 Convective Outlook
Click to see valid 1Z - 12Z Day 1 Convective Outlook
Updated: Thu Sep 3 05:49:41 UTC 2015 (Print Version | 20150903 1200Z Day 1 shapefile | 20150903 1200Z Day 1 KML)
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 Forecast Discussion
   SPC AC 030549

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1249 AM CDT THU SEP 03 2015

   VALID 031200Z - 041200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   THUNDERSTORMS ARE EXPECTED TODAY FROM THE FOUR CORNERS TO THE
   NORTHERN HIGH PLAINS AND ACROSS MUCH OF THE GREAT LAKES AND MIDWEST
   REGION INTO THE NEW ENGLAND...MID ATLANTIC AND GULF COAST REGIONS.

   ...SYNOPSIS...
   LARGE-SCALE PATTERN WILL BE CHARACTERIZED BY MEAN TROUGHING OVER W
   COAST AND RIDGING FROM SRN PLAINS NNEWD ACROSS HUDSON BAY REGION. 
   GEN-TSTM POTENTIAL OVER PAC NW WILL BE SUPPORTED BY SEVERAL
   VORTICITY MAXIMA ORBITING LARGE/COMPLEX CYCLONE OVER SRN BC...AS IT
   SHIFTS SLOWLY SWD ACROSS PAC NW.  WEAK SHORTWAVE TROUGH -- NOW
   EVIDENT IN MOISTURE-CHANNEL IMAGERY FROM 4 CORNERS SSWWD ACROSS ERN
   AZ -- IS FCST TO EJECT SLOWLY NNEWD...REACHING ROCKIES OF CENTRAL CO
   AND N-CENTRAL NM BY 4/00Z THEN FROM WRN DAKOTAS TO ERN CO BY 4/12Z. 
   WEAK PERTURBATION NOW OVER WRN/CENTRAL UPPER MI AND LM SHORE OF WI
   WILL MOVE GENERALLY EWD TO LOWER MI AND LH BY 4/00Z...THEN WEAKEN
   AND DRIFT SEWD/SWD.

   AT SFC...COLD FRONT NOW OVER QUE IS FCST TO MOVE SWD...REACHING SRN
   NEW ENGLAND AND CENTRAL/NWRN NY BY END OF PERIOD.  WRN SEGMENT OF
   THIS FRONTAL ZONE -- INITIALLY QUASISTATIONARY FROM CENTRAL LOWER MI
   ACROSS CENTRAL WI AND CENTRAL/NWRN MN -- IS EXPECTED TO MOVE LITTLE
   THROUGH PERIOD EXCEPT AS WARM FRONT ACROSS NWRN MN.  MI SEGMENT OF
   FRONT SHOULD CONTINUE TO BE DIFFUSED BY CONVECTIVE PROCESSES. 
   WAVY/QUASISTATIONARY DRYLINE WILL PERSIST FROM WRN DAKOTAS SWD TO
   BIG BEND REGION OF SW TX.

   AN ISOLATED/BRIEF TSTM NEAR SVR LIMITS CANNOT BE RULED OUT OVER ANY
   OF THESE AREAS...HOWEVER IN EACH...SVR POTENTIAL APPEARS TOO POORLY
   FOCUSED AND/OR LOW TO ASSIGN CATEGORICAL AREAS ATTM...

   ...LOWER MI TO MID/UPPER OH VALLEY REGION AND CENTRAL
   APPALACHIANS/PIEDMONT...
   SCATTERED TSTMS IN CLUSTERS ARE EXPECTED TO DEVELOP THROUGH MORNING
   AND AFTN...PERHAPS EVEN INTO EVENING...OVER THIS AREA IN RESPONSE TO
   PLENTIFUL LOW-LEVEL MOISTURE...WEAK MLCINH...DIURNAL HEATING FOR
   AFTN CONVECTION...AND OVER AFFECTED GREAT LAKES STATES...LARGE-SCALE
   ASCENT AHEAD OF SMALL SHORTWAVE TROUGH.  FCST SOUNDINGS SUGGEST
   SUFFICIENT HEATING MAY OCCUR TO OFFSET WEAK MIDLEVEL LAPSE RATES FOR
   AROUND 2000 J/KG MLCAPE TO DEVELOP...AND MOISTURE CONTENT MAY
   SUPPORT A LOCALLY DAMAGING/WATER-LOADING-RELATED DOWNBURST. 
   HOWEVER...DEEP-LAYER FLOW IS EXPECTED TO REMAIN VERY WEAK OVER THIS
   REGION...LIMITING POTENTIAL FOR ORGANIZED SVR.  AS USUAL...SUB-SVR
   GUSTS UNDER 50 KT STILL MAY DO LOCALIZED/MINOR DAMAGE OR AFFECT
   TREES.  WEAKENING OF MID/UPPER-LEVEL PERTURBATION WITH TIME...ALONG
   WITH NOCTURNAL STABILIZATION...SHOULD REDUCE CONVECTIVE
   COVERAGE/STRENGTH CONSIDERABLY THIS EVENING INTO TONIGHT.

   ...NRN/CENTRAL PLAINS...
   ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE THIS AFTN INVOF
   DRYLINE FROM DAKOTAS TO WRN NEB...AS STG SFC HEATING/MIXING REMOVES
   MLCINH AND LIFT IS AIDED BY WEAK CONVERGENCE.  FCST SOUNDINGS
   SUGGEST ABUNDANT DCAPE AND LARGE DEW-POINT DEPRESSIONS IN SUPPORT OF
   AT LEAST STG/BRIEFLY DAMAGING GUST POTENTIAL FROM A STORM OR TWO
   SOMEWHERE UP AND DOWN DRYLINE CORRIDOR.  HOWEVER...MIXING/DRYING
   ALSO SHOULD LIMIT LIQUID-WATER CONTENT OF DRYLINE STORMS AND ALSO
   KEEP MLCAPE CONSTRAINED TO LESS THAN 800 J/KG IN MOST AREAS. 
   HIGHER-BUOYANCY EXCEPTION MAY BE OVER PORTIONS ND WHERE DEEPER MOIST
   LAYER AND STRONGER DEEP SHEAR WILL EXIST CLOSER TO DRYLINE COMPARED
   TO FARTHER S.  HOWEVER...MLCINH WILL BE STRONGER AS WELL...RENDERING
   TSTM INITIATION MORE UNCERTAIN.  LARGE-SCALE ASCENT AHEAD OF
   EJECTING/WEAK 4-CORNERS SHORTWAVE MAY ENCOURAGE CONVECTIVE GROWTH
   ACROSS PARTS OF CENTRAL/ERN CO...EVEN BEHIND DRYLINE. 
   HOWEVER...WEAK FLOW SHOULD LIMIT OVERALL ORGANIZATION.

   ...SERN AZ TO CENTRAL/SRN ROCKIES...
   WIDELY SCATTERED TO SCATTERED TSTMS ARE EXPECTED TO FORM AGAIN TODAY
   OVER THIS REGION...INITIALLY OVER HIGHER TERRAIN AS DIABATIC HEATING
   PREFERENTIALLY REMOVES MLCINH.  MUCH OF THIS AREA WILL BE BEHIND
   INFLUENCE OF EJECTING 4-CORNERS PERTURBATION...BUT STILL WITHIN
   PERSISTENT PLUME OF LOW/MIDDLE-LEVEL MOISTURE.  FCST SOUNDINGS
   SUGGEST PRECONVECTIVE MLCAPES 500-1000 J/KG ARE POSSIBLE...WITH
   SPOTTY AREAS WHERE INVERTED-V BOUNDARY-LAYER THERMODYNAMIC PROFILES
   DEVELOP IN SUPPORT OF STG GUSTS.  HOWEVER...CONVECTION SHOULD REMAIN
   RATHER DISORGANIZED GIVEN WEAK LOW/MIDDLE-LEVEL WINDS AND LACK OF
   SUBSTANTIAL UPPER SUPPORT.

   ..EDWARDS/COOK.. 09/03/2015

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z

        
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