May-24-2004 1300 UTC Day 1 Convective Outlook
Created: Mon May 24 13:23:59 UTC 2004
Public Severe Weather Outlook

The SPC is forecasting an outbreak of severe thunderstorms today and tonight across portions of the United States. This is an extremely dangerous situation. Please read the latest public statement about this event.

Categorical Graphic
20040524 1300 UTC Day 1 Outlook Graphic
Probablistic Tornado Graphic
20040524 1300 UTC Day 1 Tornado Probabilities Graphic
Probablistic Damaging Wind Graphic
20040524 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probablistic Large Hail Graphic
20040524 1300 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 241310
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0810 AM CDT MON MAY 24 2004
   
   VALID 241300Z - 251200Z
   
   THERE IS A HIGH RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 NNW
   OMA 20 WNW MLI 35 N PIA 20 WSW BMI 15 SSE SPI 35 NW STL 30 E OJC 20
   ENE MHK 35 SW BIE 30 WSW LNK 25 NNW OMA.
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 SSW
   SUX 40 NNE MLI 10 W MMO 30 ENE BMI 15 SW CMI 10 SSW ALN 40 SSE SZL
   15 ESE EMP 20 E SLN 10 W CNK 25 ENE HSI 20 SW OLU 25 SSW SUX.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 SE
   MHE 30 N FOD 10 WNW DBQ 35 E RFD 40 SW SBN 30 E LAF 20 SSE HUF 40
   ESE TBN 25 WSW JLN 15 SW PNC 25 SSW LTS 25 SSW CDS 65 SW GAG 55 WNW
   CNK 25 NW GRI 30 ESE ANW 60 SSE 9V9 20 SE MHE.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 SE
   NEL 35 SW AVP 20 WNW ROC ...CONT... 25 NNE PBG 20 NNE EEN 10 W HYA.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 60 NNE BML 20 E BHB
   ...CONT... 30 E INL 50 W IWD 15 NW AUW 40 SW MKG 35 WSW TOL 10 WSW
   MFD 15 N CAK 20 NNE YNG 10 N ERI ...CONT... 40 NW CTB 50 WNW GTF 20
   NNE BZN 50 SW BIL 35 WNW SHR 25 WNW GCC 35 SE 81V 35 NE CDR 55 W VTN
   45 SSE PHP 35 ENE DIK 55 NNW ISN.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 65 SSW MRF 35 WNW MAF
   35 NNE PVW 55 S LBL LBL 30 W GCK 50 ENE LAA LHX 35 SSE MTJ 45 NNE
   4BL 60 E ELY 45 SSW EKO 45 NNW WMC 45 NNE 4LW 50 E SLE 10 S SEA 35
   NE BLI ...CONT... 35 SE JAX 35 N GNV 35 ESE VLD 35 WNW AYS 20 SSW
   MCN 20 NNW LGC 45 NW BHM 20 WNW UOX 20 SW LIT 25 SSE MLC 25 S ADM 35
   NNE BWD 55 SSE DRT.
   
   ...THERE IS A HIGH RISK OF SVR TSTMS THIS AFTERNOON AND EVENING
   ACROSS SERN NEB...NERN KS...SRN IA...NRN MO AND WEST CENTRAL IL...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA
   FROM SERN NEB/NERN KS TO CENTRAL PORTIONS IL...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
   AREA AND EXTENDS SWWD INTO WRN OK/ERN TX PANHANDLE...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS CENTRAL-ERN NY/NERN PA
   TO WRN/SRN NEW ENGLAND...
   
   ...OUTBREAK OF SEVERE THUNDERSTORMS INCLUDING STRONG TORNADOES...
   VERY LARGE HAIL...AND WIDESPREAD DAMAGING WINDS OVER PARTS OF THE
   LOWER MISSOURI AND MID MISSISSIPPI VALLEYS TODAY THROUGH TONIGHT...
   
   ...LOWER MO TO MID MS VALLEYS...
   SHORT WAVE TROUGH...CURRENTLY MOVING ACROSS SE CO...IS EXPECTED TO
   TRACK ENEWD TO NORTH CENTRAL KS BY 18Z...AND THEN EWD TO THE SRN
   GREAT LAKES BY 12Z TUESDAY.  INCREASING SLY LOW-LEVEL FLOW DURING
   THE LAST SEVERAL HOURS HAS RESULTED IN A RETURN OF A VERY MOIST AIR
   MASS INTO CENTRAL-ERN KS...WITH SURFACE DEWPOINTS ALREADY NEAR 70 F
   FROM ICT-EMP.  SURFACE LOW CURRENTLY OVER ERN CO WILL MOVE ENEWD
   REACHING SERN NEB BY 00Z...WITH MOIST SLY FLOW ALLOWING THE WARM
   FRONT TO RETREAT FARTHER NWD ACROSS NRN MO BY EARLY EVENING. 
   MID-HIGH LEVEL CLOUD SHIELD...CURRENTLY EXTENDING ACROSS CENTRAL-ERN
   PORTIONS OF NEB/KS IS EXPECTED TO MOVE EAST OF THE WRN PORTION OF
   THE MODERATE/HIGH RISK AREAS ALLOWING FOR STRONG SURFACE HEATING
   TODAY. THIS COMBINED WITH INCREASING SURFACE DEWPOINTS INTO THE
   UPPER 60S/LOWER 70S ALONG/S OF WARM FRONT AND PLUME OF STEEP LAPSE
   RATES /AOA 8 C/KM/ SPREADING ACROSS THIS REGION WILL RESULT IN VERY
   STRONG TO EXTREME INSTABILITY. INCREASING SWLY MID-LEVEL FLOW ATOP
   INCREASING SLY LLJ ACROSS ERN KS/WRN MO INTO IA BY AFTERNOON WILL
   SUPPORT SUFFICIENT DEEP LAYER SHEAR AND CURVED HODOGRAPHS FOR
   LONG-LIVED TORNADIC SUPERCELLS WITH VERY LARGE HAIL.  AS LARGE SCALE
   ASCENT SPREADS ACROSS ERN NEB/NERN KS BETWEEN 18-21Z AHEAD OF THE SE
   CO TROUGH...STORMS ARE EXPECTED TO INITIATE ACROSS SERN NEB AND THEN
   DEVELOP EAST/ESEWD ALONG THE RETREATING WARM FRONT INTO SWRN IA/NERN
   KS/NWRN MO WITH A CONTINUED ATTENDANT THREAT OF STRONG TORNADOES AND
   VERY LARGE HAIL.
   
   SHORT WAVE TROUGH MOVING EWD TOWARD SRN GREAT LAKES REGION THIS
   EVENING/OVERNIGHT WILL CAUSE THE LLJ TO VEER TO SWLY OVER NRN MO
   THIS EVENING...AND SUPPORT THE EVOLUTION OF A SEVERE FORWARD
   PROPAGATING MCS AROUND 00Z ACROSS SWRN-SOUTH CENTRAL IA/NWRN- NORTH
   CENTRAL MO.  DESTRUCTIVE WINDS CAN BE ANTICIPATED WITH THE FAST
   MOVING BOW ECHO AS IT MOVES EWD ACROSS SRN IA/NRN MO THIS EVENING
   AND INTO CENTRAL PORTIONS OF IL TONIGHT.
   
   CAP IS EXPECTED TO BE STRONGER SWD ACROSS THE SRN PLAINS...THOUGH
   POINT FORECAST SOUNDINGS SUGGEST THE CAP SHOULD WEAKEN ENOUGH ALONG
   THE DRY LINE SWD FROM SRN KS INTO WRN OK/ERN TX PANHANDLE FOR
   ISOLATED SUPERCELLS GIVEN THE EXPECTED CAPE/SHEAR VALUES.
   
   ...PORTIONS NY/NERN PA TO WRN/SRN NEW ENGLAND...
   SHORT WAVE TROUGH WILL TRACK FROM THE LOWER GREAT LAKES EWD TO NEW
   ENGLAND THIS FORECAST PERIOD.  POCKETS OF HEATING AHEAD OF ONGOING
   THUNDERSTORM COMPLEX OVER WRN-CENTRAL NY SHOULD ALLOW THE AIR MASS
   TO DESTABILIZE SUFFICIENTLY BY 18Z WHILE DEEP LAYER SHEAR WILL BE
   STRONG ENOUGH FOR ORGANIZED SEVERE STORMS.  A SECOND ROUND OF SEVERE
   STORMS IS POSSIBLE IN THE WAKE OF THIS ACTIVITY AS THE MAIN UPPER
   TROUGH MOVES ACROSS NY INTO WRN-SRN NEW ENGLAND LATE THIS AFTERNOON
   INTO THE EVENING.  50-60 KT OF WLY MID-LEVEL FLOW WILL SUPPORT
   PRIMARILY A DAMAGING WIND THREAT TODAY...THOUGH STEEP LAPSE RATES
   WILL ALSO FAVOR A HAIL THREAT.
   
   ...TN VALLEY TO SRN-CENTRAL APPALACHIANS TO MID ATLANTIC STATES...
   THE DEVELOPMENT OF MODERATE INSTABILITY ACROSS THIS REGION SHOULD
   PROVE FAVORABLE ONCE AGAIN FOR THE DEVELOPMENT OF PULSE-TYPE
   STORMS...WITH HAIL/DAMAGING WIND GUSTS THE PRIMARY THREATS GIVEN
   WEAK DEEP LAYER SHEAR/UPPER FORCING.
   
   ...NRN PLAINS...
   STRONGER SHORT WAVE TROUGH/SURFACE LOW...CURRENTLY OVER THE NRN HIGH
   PLAINS...WILL TRACK ENEWD ACROSS THE DAKOTAS TO NRN MN THIS FORECAST
   PERIOD.  WARM FRONT ASSOCIATED WILL MOVE NEWD ACROSS THE ERN DAKOTAS
   THIS AFTERNOON AND TOWARD THE WRN GREAT LAKES OVERNIGHT.  EXTENSIVE
   CLOUDINESS ACROSS THE NRN PLAINS/MN WILL LIMIT THE DEGREE OF SURFACE
   HEATING...THOUGH STEEP MID-LEVEL LAPSE RATES AND SURFACE DEWPOINTS
   IN THE 50S SHOULD RESULT IN MARGINAL INSTABILITY.  THIS COMBINED
   WITH LARGE SCALE ASCENT WITH THE UPPER TROUGH AND SUFFICIENT DEEP
   LAYER SHEAR SHOULD SUPPORT ISOLATED SEVERE STORMS MAINLY DURING THE
   AFTERNOON.
   
   ..PETERS/GUYER.. 05/24/2004
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 1630Z