May 19, 2010 2000 UTC Day 1 Convective Outlook
Updated: Wed May 19 20:00:21 UTC 2010
Probabilistic to Categorical Outlook Conversion Table
Public Severe Weather Outlook

The SPC is forecasting ...severe thunderstorms expected over parts of the southern plains this afternoon and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20100519 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20100519 2000 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20100519 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20100519 2000 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 191958
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0258 PM CDT WED MAY 19 2010
   
   VALID 192000Z - 201200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS CENTRAL OK...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA 
   OVER A LARGE PART OF OK AND NRN TX...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK 
   AREA...FROM SW KS INTO THE LWR MS VLY....
   
   PREVIOUS FORECAST ON TRACK WITH ONLY MINOR ADJUSTMENTS.
   
   CONVECTION HAS RECENTLY DEVELOPED NEAR WARM FRONT/DRYLINE
   INTERSECTION IN WRN OK AND MAY ALSO DEVELOP SHORTLY ALONG LOW LEVEL
   CONFLUENCE LOCATED EAST OF OKC. AS DRYLINE AND UPPER TROUGH
   SHIFT EWD...STORMS SHOULD INCREASE IN COVERAGE AND INTENSITY INTO
   THE EVENING HOURS...REFERENCE WW 190. SURFACE OBSERVATIONS SHOW
   BOUNDARY LAYER WINDS HAVE VEERED ACROSS SWRN OK AND WEAKENED
   SOMEWHAT ALOFT AS VORTEX2 SOUNDING IN WRN OK SHOWED 850 MB WINDS
   WERE 210/15KT COMPARED TO 35 KT AT OKC AT THE SAME TIME. REORIENTED
   THE HIGH RISK AREA ALONG WARM FRONT...WHERE LOW LEVEL JET/SHEAR WILL
   BE MAXIMIZED THROUGH EARLY EVENING. THE HIGH RISK EXTENDS FROM NW OF
   OKC ESEWD TO THE MUSKOGEE/MCALESTER AREAS AND HAS THE HIGHEST
   POTENTIAL FOR SIGNIFICANT TORNADOES AS WELL AS EXTREME HAIL/DAMAGING
   WINDS. MLCAPE VALUES TO 3000 J/KG SOUTH OF WARM FRONT AND STRONGER
   LOW LEVEL SHEAR NORTH OF WARM FRONT WILL FAVOR STRONG SUPERCELLS
   WITH TORNADOES...LARGE HAIL AND DAMAGING WINDS ESPECIALLY ACROSS THE
   MODERATE RISK AREA.
   
   LATER TONIGHT...STORMS ARE EXPECTED TO CONGEAL INTO AND ONE OR MORE
   MCS/S. IT APPEARS LIKELY THAT THESE SYSTEMS WILL ADVANCE FURTHER EWD
   THAN EARLIER ANTICIPATED...SO THE SLIGHT RISK HAS BEEN EXTENDED
   FURTHER EWD INTO PORTIONS OF SRN MO/AR FOR LATE TONIGHT. THE
   CONSOLIDATED OUTFLOW AND STRENGTHENING SWLY FLOW ALOFT INDICATES THE
   PRIMARY THREAT SHOULD BE DAMAGING WINDS.
   
   ..IMY.. 05/19/2010
   
   .PREV DISCUSSION... /ISSUED 1130 AM CDT WED MAY 19 2010/
   
   ...SIGNIFICANT SVR TSTM OUTBREAK EXPECTED THIS AFTN THROUGH TONIGHT
   FOR A LARGE PART OF OK AND ADJACENT N TX...
   
   ...SYNOPSIS...
   NE CO UPR LOW WILL MOVE SLOWLY E INTO CNTRL KS BY 12Z THU AS
   ASSOCIATED SHORTWAVE TROUGH NOW EXTENDING SSW INTO NM SWEEPS E INTO
   CNTRL OK/N CNTRL TX.  BAND OF SEASONABLY STRONG CYCLONIC WSW FLOW ON
   S SIDE OF LOW WILL PERSIST OVER THE SRN PLNS...ATOP MODERATE SSWLY
   LLJ.  MAIN SYNOPTIC FRONTAL ZONE EXTENDING SE FROM TX PANHANDLE SFC
   LOW SHOULD EDGE SLOWLY NE THROUGH THE PERIOD... WITH MOVEMENT OFFSET
   BY CONVECTIVE OUTFLOW.  S OF THE FRONT AND E OF LEE TROUGH/DRY LINE
   OVER THE ERN PANHANDLE...LOW LVL MOISTURE WILL CONTINUE TO SPREAD
   NWD WITH LLJ.
   
   ...SRN PLNS/ARKLATEX THROUGH EARLY WED...
   OVERNIGHT OK MCS SHOULD FURTHER WEAKEN AS CONTINUES GENERALLY ESE
   INTO NW AR EARLY THIS AFTN.  ELEVATED STORMS...A FEW OF WHICH MAY BE
   ACCOMPANIED BY HAIL...LIKELY WILL PERSIST THROUGH THE DAY ATOP W/E
   OUTFLOW BOUNDARY LEFT BY THE MCS.
   
   BY MID TO LATE AFTN...COMBINATION OF SFC HEATING...CONTINUED LOW LVL
   MOISTURE INFLOW...AND LEADING EDGE OF ASCENT WITH NM UPR TROUGH
   EXPECTED TO SUPPORT NEW SFC-BASED STORMS NEAR INTERSECTION OF
   OUTFLOW BOUNDARY WITH EWD-MOVING LEE TROUGH/DRY LINE OVER WRN OK.  A
   BIT LATER...SCTD DEVELOPMENT SHOULD EXTEND SWD ON THE TROUGH/DRY
   LINE INTO NW TX...AND EWD ALONG OUTFLOW BOUNDARY INTO CNTRL OK.
   
   THE STORMS WILL QUICKLY BECOME SUPERCELLS GIVEN 40-50 KT DEEP WSWLY
   SHEAR AND SBCAPE OF 2500-3000 J/KG.  THE SETUP APPEARS MOST
   FAVORABLE FOR LARGE...RELATIVELY SLOW MOVING INTENSE STORMS WITH
   LARGE HAIL.  GIVEN SIZABLE LOW LVL DIRECTIONAL COMPONENT TO
   SHEAR...ESPECIALLY NEAR REMNANT OUTFLOW BOUNDARY AND/OR FRONT...A
   COUPLE STRONG TORNADOES ALSO MAY OCCUR.
   
   WITH THE LLJ LIKELY TO STRENGTHEN AND VEER DUE TO DIURNAL INFLUENCES
   AND THE CONTINUED EWD MOVEMENT OF NM TROUGH...EXPECT THE OK/N TX
   STORMS TO EVOLVE INTO A LARGE MCS EARLY TONIGHT.  COUPLED WITH
   INCREASINGLY DIFLUENT HI LVL FLOW...THIS SYSTEM SHOULD CONTINUE ESE
   INTO AR BY EARLY WED...WITH AN ATTENDANT THREAT FOR DMGG WIND/HAIL
   AND VERY HEAVY RAIN.
   
   ...ARKLATEX TO CNTRL GULF CST THIS AFTN...
   SFC HEATING ALONG/S AFOREMENTIONED SYNOPTIC FRONT EXTENDING SE FROM
   SRN PLNS LOW MAY SUPPORT SCTD DIURNAL STORMS FROM THE ARKLATEX SE TO
   THE CNTRL GULF CST TODAY.  THIS ACTIVITY WILL BE CONDITIONAL ON
   HEATING AND LOW LVL CONVERGENCE BECOMING LOCALLY SUFFICIENT TO
   OVERCOME WEAK CIN OVER REGION.  AMPLE INSTABILITY/ PW WILL BE
   PRESENT FOR STRONG UPDRAFTS AND PERHAPS ISOLD SVR WIND GUSTS/HAIL. 
   BUT WEAK SHEAR SHOULD LIMIT STORM ORGANIZATION/ PERSISTENCE.
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z