Jun 3, 2014 2000 UTC Day 1 Convective Outlook | |||||||||||||||||
Updated: Tue Jun 3 20:03:44 UTC 2014 (![]() ![]() | |||||||||||||||||
Probabilistic to Categorical Outlook Conversion Table | |||||||||||||||||
Public Severe Weather Outlook | |||||||||||||||||
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The SPC is forecasting ...Severe thunderstorms expected over parts of the middle and lower Missouri Valley into the middle Mississippi Valley this afternoon and tonight.... Please read the latest public statement about this event. View What is a Watch? clip. |
Categorical Graphic | |||||||||||||||||
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Probabilistic Tornado Graphic | |||||||||||||||||
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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. |
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Probabilistic Damaging Wind Graphic | |||||||||||||||||
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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. |
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Probabilistic Large Hail Graphic | |||||||||||||||||
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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. |
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SPC AC 032000 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CDT TUE JUN 03 2014 VALID 032000Z - 041200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF EASTERN NEBRASKA...WESTERN AND SOUTHERN IOWA...AND FAR NORTHEAST MISSOURI THIS AFTERNOON THROUGH LATE EVENING... ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK FROM PARTS OF NORTHERN AND EASTERN NEBRASKA TO NORTHERN MISSOURI AND WESTERN ILLINOIS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK AREA FROM THE NORTHERN HIGH PLAINS TO THE MID MISSISSIPPI VALLEY/MIDWEST... ...SUMMARY... AN OUTBREAK OF SEVERE STORMS IS FORECAST THIS AFTERNOON THROUGH TONIGHT FROM PARTS OF NEBRASKA THROUGH IOWA...NORTHERN MISSOURI...AND INTO ILLINOIS. DESTRUCTIVE WINDS...VERY LARGE HAIL...AND A COUPLE OF STRONG TORNADOES ARE EXPECTED. ...NEB TO IA/MO THROUGH LATE EVENING... AN ONGOING BOW THAT HAS BEEN PRODUCING DAMAGING WINDS AND VERY LARGE HAIL /EXCEEDING 2-2.5 INCH DIAMETER/ IS EXPECTED TO PROGRESS ESEWD THROUGH ERN NEB INTO WRN AND SRN IA THROUGH THE LATE AFTERNOON INTO THE EVENING. GIVEN THE ENVIRONMENT DOWNSTREAM OF THIS BOW INTO SRN IA HAS BEEN DESTABILIZING WITH MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR ALREADY SUPPORTIVE OF CONTINUED STORM ORGANIZATION...A NARROW CORRIDOR FROM MAINLY ERN NEB INTO WRN AND SRN IA HAS BEEN UPGRADED TO A HIGH RISK. ...NRN HIGH PLAINS... SEVERE PROBABILITIES HAVE BEEN ADJUSTED TO INCLUDE MORE OF NWRN SD...SERN MT AND INTO FAR SWRN ND IN THE SLIGHT RISK FOR MAINLY A THREAT FOR HAIL AND STRONG/DAMAGING WIND GUSTS. HOWEVER...A TORNADO THREAT CANNOT BE RULED OUT. FOR ADDITIONAL DETAILS...REFER TO SPC MESOSCALE DISCUSSION 795 AND WW 208. ..PETERS.. 06/03/2014 .PREV DISCUSSION... /ISSUED 1129 AM CDT TUE JUN 03 2014/ ...SYNOPSIS... FAST-MOVING SHORTWAVE TROUGH AND ASSOCIATED 70KT MID-LEVEL SPEED MAX CURRENTLY CROSSING THE GREAT BASIN/INTERMOUNTAIN WEST WILL CREST A STRONG SUB-TROPICAL RIDGE AND PRODUCE MODEST MID-LEVEL HEIGHT FALLS ACROSS THE CENTRAL PLAINS THROUGH THIS EVENING. IN ADDITION TO SPURRING LEE-SIDE CYCLOGENESIS ACROSS THE CENTRAL HIGH PLAINS...LARGE SCALE ASCENT ASSOCIATED WITH THE MID/UPPER DISTURBANCE WILL BE FOCUSED ALONG AND NORTH OF A WARM FRONT SITUATED FROM NEB PANHANDLE ESEWD TO NEAR THE IA/MO BORDER. A BROAD ZONE OF SFC LOW PRESSURE OVER ERN WY/CO WILL CONSOLIDATE INTO LEE-CYCLONE AND TRACK TO WRN NEB BY THIS EVENING. ADDITIONAL MESO-LOWS/FRONTAL WAVES MAY FORM AND TRACK EAST ALONG THE WARM FRONT...AIDED BY LATENT HEATING/DEEP CONVECTION...INTO LATE EVENING. SOUTH OF THE LOW/WARM FRONT...A DRYLINE/THERMAL TROUGH WILL STRENGTHEN THROUGH THE AFTERNOON AND EXTEND FROM WRN NEB SSWWD THROUGH WRN KS TO FAR ERN NM. IN THE EAST...COLD FRONT ASSOCIATED WITH DEEP LOW PRESSURE NEAR JAMES BAY WILL CONTINUE EAST FROM ERN GREAT LAKES TO NEW ENGLAND. ...SD/NEB TO IA/MO THROUGH LATE EVENING... INTENSE STORMS POSING PRIMARILY A THREAT FOR LARGE HAIL ARE ALREADY UNDERWAY NORTH OF SFC WARM FRONT AND NEAR THE SD/NE BORDER THIS MORNING /REF WW 206/. THIS CONVECTION WAS LIKELY ROOTED ABOVE THE 850MB LEVEL IN AN ENVIRONMENT CHARACTERIZED BY STEEPENING MID-LEVEL LAPSE RATES AND STRONG VERTICAL SHEAR. EXPECT THESE ELEVATED STORMS TO PERSIST GIVEN MASS AND MOISTURE FLUXES NOW UNDERWAY IN RESPONSE TO LARGE SCALE ASCENT AND DIABATIC PROCESSES. BY MID-AFTERNOON...ELEVATED STORMS WILL CONTRIBUTE TO... 1) A REINFORCEMENT OF THE EXISTING LOW LEVEL BAROCLINIC ZONE/WARM FRONT...AND 2) A DEEPENING COLD POOL ALONG AND NORTH OF THE FRONT. MODEST TO LOCALLY STRONG WARM SECTOR SFC HEATING WILL CONTRIBUTE TO WEAKENING INHIBITION AND AN INCREASING POTENTIAL FOR CONVECTION TO BECOME ROOTED IN A VERY UNSTABLE BOUNDARY LAYER NEAR THE FRONT BY LATE AFTERNOON. ADDITIONAL STORMS ARE EXPECTED TO INCREASE WITHIN THE LOW-LEVEL UPSLOPE FLOW REGIME OVER PARTS OF SD/NEB. A FEW MODELS SUPPORT AT LEAST ISOLATED WARM SECTOR DISCRETE STORMS BY LATE AFTERNOON/EARLY EVENING ACROSS CNTRL/ERN NEB. ANY DISCRETE STORMS INITIATING NEAR THE WARM FRONT WILL EXIST IN AN IDEAL ENVIRONMENT FOR TORNADIC SUPERCELLS WITH EFFECTIVE SRH IN EXCESS OF 200 M2/S2 AND RELATIVELY LOW LFC. AWAY FROM THE FRONT AND NEAR THE DRYLINE...HEATING AND DEEPER MIXING MAY OFFSET THE TORNADO POTENTIAL SOMEWHAT AND RESULT IN MORE OUTFLOW-DOMINANT STORMS WITH HIGH WIND AND VERY LARGE HAIL POTENTIAL. WHILE ABOVE SCENARIO HAS LOW TO MODEST CONFIDENCE...GREATER CONFIDENCE EXISTS IN THE CONTINUATION AND GRADUAL UPSCALE GROWTH OF ONGOING CONVECTION INTO AN COMPLEX OF EVEN MORE INTENSE STORMS...INCLUDING EMBEDDED SUPERCELLS...MOVING ESEWD TO ERN NEB AND THEN TO SRN IA/NRN MO THROUGH THE LATE EVENING. THIS CONVECTION WILL DEVELOP INTO AN AXIS OF STRONG INSTABILITY /SBCAPE TO 3000-4000 J PER KG/ COINCIDENT WITH INTENSIFICATION OF A WLY 60-70KT MID-LEVEL JET. BOTH PARALLEL ARW/NMMB HIRES WINDOWS DEPICT THIS SCENARIO QUITE WELL BUT STILL OFFER DIFFERING OUTCOMES IN TIME/INTENSITY AND PLACEMENT OF GREATEST HIGH WIND POTENTIAL. THUS...WILL MAINTAIN A RELATIVELY HIGH CONFIDENCE FORECAST IN DERECHO EVOLUTION ACROSS NEB/IA/MO AREA THROUGH THE LATE EVENING. EXPECT AN INCREASING CHANCE FOR WIDESPREAD DAMAGING WINDS...LARGE HAIL...AND A COUPLE OF POTENTIALLY STRONG TORNADOES IN THESE AREAS. IF CONFIDENCE CONTINUES TO INCREASE IN THIS WIDESPREAD SEVERE WIND SCENARIO...A HIGH RISK AREA MAY BE ADDED IN THE AFTERNOON SWODY1 UPDATE. ...ACROSS THE MS RIVER TO IL/IND BEFORE DAYBREAK WED... MCS/DERECHO SHOULD MAINTAIN DAMAGING WIND AND SOME HAIL POTENTIAL EAST ACROSS THE MS RIVER AND INTO IL/IND...ESPECIALLY AFTER MIDNIGHT CDT. WHILE BOUNDARY LAYER STABILIZATION MAY ACT TO OFFSET MORE SUBSTANTIAL WIND THREAT WITH TIME...UPSCALE STORM ORGANIZATION AND CONTINUING LARGE SCALE SUPPORT FOR ASCENT SUGGESTS AT LEAST MODEST SEVERE WIND PROBABILITIES/SLGT RISK AREA IS WARRANTED AS FAR EAST AS CENTRAL IND THROUGH DAYBREAK WED. ...LOWER GREAT LAKES/OH VALLEY NEWD TO CHAMPLAIN VALLEY... DIURNAL HEATING OF MIDDLE 60S-LOWER 70S PRE-FRONTAL SFC DEWPOINTS WILL SUPPORT POCKETS OF MLCAPE FROM 1000 TO 2000 J/KG THIS AFTERNOON. THE STRONGEST INSTABILITY IS FORECAST TO OCCUR ACROSS THE OHIO VALLEY -- I.E. IN THE WAKE OF A BAND OF WEAK H85-H7 WARM ADVECTION AND ASSOCIATED CLOUDS/PRECIPITATION CROSSING THE CNTRL APPALACHIANS. LOW-LEVEL ASCENT ALONG AND AHEAD OF A COLD FRONT CROSSING THE GREAT LAKES WILL BE WEAK...BUT SHOULD BE SUFFICIENT FOR ISOLATED TO WIDELY SCATTERED THUNDERSTORMS. THIS ASCENT WILL BE LOCALLY AUGMENTED BY DIFFERENTIAL-HEATING-INDUCED BAROCLINICITY AHEAD OF THE ZONE OF WARM ADVECTION -- I.E. ACROSS NRN NY TO THE CHAMPLAIN VALLEY. HOWEVER...GIVEN THE MAGNITUDE OF THE AFOREMENTIONED BUOYANCY AND 30-40 KT OF MID-LEVEL FLOW...SPORADIC INSTANCES OF DMGG WINDS AND MARGINALLY SVR HAIL WILL BE POSSIBLE WITH CONVECTION PRIMARILY ORGANIZED IN MULTICELL CLUSTERS. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |