Apr 2, 2012 0600 UTC Day 1 Convective Outlook | |
Updated: Mon Apr 2 06:03:33 UTC 2012 | |
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic |
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Probabilistic Tornado 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. |
Probabilistic Damaging Wind 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. |
Probabilistic Large Hail 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. |
SPC AC 020600 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT MON APR 02 2012 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND CENTRAL PLAINS EWD INTO E TX/SRN AR AND MUCH OF LA... ...SYNOPSIS.... MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING THE SRN EXTENT OF THE WRN U.S. TROUGH BECOMING CUT-OFF FROM THE NRN STREAM BY THE START OF DAY 1. THE CLOSED LOW WILL MOVE SLOWLY EWD TODAY ACROSS NM...GIVEN THE PRESENCE OF A RATHER STRONG DOWNSTREAM RIDGE EXTENDING NWD FROM THE LOWER MS VALLEY/CENTRAL GULF COAST STATES TO THE WRN GREAT LAKES. MEANWHILE...HEIGHTS WILL RISE ACROSS THE SERN STATES AS A TROUGH LOCATED ALONG THE MIDDLE/NRN ATLANTIC COAST MOVES EWD. A WEAK MIDLEVEL CIRCULATION...CURRENTLY MOVING SLOWLY NWD INLAND FROM THE MID-UPPER TX COAST...SHOULD TRACK NEWD TODAY THROUGH E TX/ARKLATEX AND LOWER MS VALLEY REACHING THE OZARKS AND NRN MS BY 12Z TUESDAY. THE NRN EXTENT OF THE WRN TROUGH...CURRENTLY MOVING EWD THROUGH THE NRN INTERMOUNTAIN WEST PER WATER VAPOR IMAGERY...IS EXPECTED TO TRACK ENEWD THROUGH THE NRN HIGH PLAINS THIS AFTERNOON AS IT PHASES WITH A SEPARATE TROUGH MOVING THROUGH CENTRAL CANADA. MODELS DIFFER WITH THE EFFECT THE SRN PORTION OF THESE PHASED TROUGHS HAS ACROSS NRN MN...BUT THE 12Z ECMWF/00Z GFS AGREE THAT 40-60 METER HEIGHT FALLS SHOULD OCCUR ACROSS THAT REGION MONDAY NIGHT. AT THE SURFACE...A COLD FRONT WILL ADVANCE E/SEWD INTO THE UPPER MS VALLEY THIS FORECAST PERIOD...AND SWD WHERE IT WILL MERGE WITH A NE-SW ORIENTED DRY LINE ACROSS CENTRAL KS THIS AFTERNOON. THE DRY LINE WILL THEN EXTEND SWD FROM A TRIPLE POINT OVER SWRN-SOUTH CENTRAL KS THROUGH WRN OK TO CENTRAL TX THIS AFTERNOON. THE WRN EXTENT OF A WARM FRONT...INITIALLY LOCATED OVER NRN MO...IS EXPECTED TO SPREAD NWD AND REACH ERN IA/NWRN IL BY THIS EVENING. MEANWHILE...A COLD FRONT WILL MOVE SWD THROUGH THE CAROLINAS REACHING ERN GA BY 12Z TUESDAY. ...CENTRAL TX/WRN AND CENTRAL OK/CENTRAL AND ERN KS... A SHORTWAVE TROUGH...CURRENTLY MOVING INTO THE BASE OF THE WRN TROUGH OVER SWRN AZ PER WATER VAPOR IMAGERY...IS EXPECTED TO MIGRATE THROUGH THE SERN-ERN PERIPHERY OF THE PARENT CLOSED LOW TODAY ACROSS SW-W TX INTO WRN OK AND POSSIBLY SWRN KS BY 03/00Z. WEAK HEIGHT FALLS ACROSS THE SRN PLAINS...DPVA ATTENDANT TO THE MIGRATORY SHORTWAVE TROUGH...AND DIFFLUENT MID-UPPER LEVEL FLOW ALL EXPECTED ACROSS THE DRY LINE DURING THE MID-LATE AFTERNOON SUGGEST TSTM DEVELOPMENT WILL BE LIKELY FROM CENTRAL/SOUTH CENTRAL TX NWD THROUGH WRN OK TO SOUTH CENTRAL KS. THE STRONGEST LOW LEVEL CONVERGENCE SHOULD EXTEND FROM NWRN OK/ADJACENT KS NEAR THE TRIPLE POINT NEWD ALONG THE COLD FRONT/DRY LINE MERGER INTO CENTRAL KS...WITH MUCH OF THE KS TSTM ACTIVITY EXPECTED TO BE MORE ANAFRONTAL-TYPE DEVELOPMENT. SURFACE HEATING WITHIN THE WARM SECTOR COMBINED WITH VERY STEEP MIDLEVEL LAPSE RATES /EXCEEDING 8 C PER KM/...AND SURFACE DEWPOINTS IN THE 60S WILL RESULT IN MODERATE TO VERY STRONG INSTABILITY WITHIN THE TX/OK/KS PORTION OF THE SLIGHT RISK AREA. EFFECTIVE BULK SHEAR WILL BE STRONGEST ACROSS S TO N CENTRAL TX WITH SHEAR VECTORS ORIENTED PERPENDICULAR TO THE DRY LINE. THIS WILL PROVE FAVORABLE FOR DISCRETE SUPERCELLS PRODUCING HAIL...SOME VERY LARGE /EXCEEDING 2 INCH DIAMETER/...AND A COUPLE OF TORNADOES. ALTHOUGH DEEP LAYER SHEAR WILL DECREASE WITH NWD EXTENT...WITH A GREATER POTENTIAL FOR PULSE-TYPE STORMS INTO KS...THE PRESENCE OF STRONG INSTABILITY WILL SUPPORT VERY LARGE HAIL WITH THIS ACTIVITY AS WELL. THE THREAT FOR AN ISOLATED TORNADO WILL ALSO EXTEND NWD THROUGH WRN OK TO THE TRIPLE POINT IN SWRN-S CENTRAL KS. ...E TX/MUCH OF LA/SRN AR... THE AIR MASS IS EXPECTED TO BECOME MODERATELY UNSTABLE ACROSS MUCH OF THIS REGION INTO THE AFTERNOON. FORCING FOR ASCENT ATTENDANT TO THE NEWD MOVING MIDLEVEL CIRCULATION WILL SUPPORT WIDESPREAD TSTM DEVELOPMENT. EFFECTIVE BULK SHEAR AROUND 30 KT SUGGESTS MULTICELLS WILL BE THE PRIMARY STORM MODE WITH AN ATTENDANT THREAT FOR HAIL AND STRONG WIND GUSTS. ...UPPER MS VALLEY/WRN GREAT LAKES TO NRN IL/IND... A FEW STRONG TO ISOLATED SEVERE ELEVATED STORMS ARE POSSIBLE AT THE START OF DAY 1 FROM ERN SD INTO NRN MN WITHIN A STRONG LOW LEVEL WAA REGIME. WEAK-MODERATE ELEVATED INSTABILITY AND 25-30 KT OF EFFECTIVE BULK SHEAR SUPPORT THIS MARGINAL SEVERE HAIL THREAT. ELEVATED CONVECTION/EMBEDDED TSTMS ARE POSSIBLE FROM NERN SD INTO NRN MN THROUGH THE DAY...BUT WEAKER INSTABILITY WILL PRECLUDE A SEVERE WEATHER THREAT. A GREATER COVERAGE OF TSTMS...AGAIN MAINLY ELEVATED...IS EXPECTED TO DEVELOP BY EARLY EVENING ACROSS PARTS OF SRN MN/POTENTIALLY NRN IA...NEAR AND N OF A SURFACE LOW MOVING INTO NWRN IA FROM NEB TODAY. IF SURFACE BASED STORMS CAN DEVELOP NEAR THE LOW IN IA...THEN THE SLIGHT RISK AREA MAY NEED TO BE EXTENDED NWD...AS MODERATE TO STRONG INSTABILITY WOULD SUPPORT A GREATER SEVERE WEATHER THREAT. OTHERWISE...A STRENGTHENING/VEERING LLJ FROM THE UPPER MS VALLEY INTO THE WRN GREAT LAKES IS EXPECTED TO SUPPORT ELEVATED TSTMS DEVELOPING AND SPREADING ESEWD ACROSS THESE AREAS. ALTHOUGH EFFECTIVE BULK SHEAR IS FORECAST TO WEAKEN OVER THE WRN GREAT LAKES TO NRN IL/IND MONDAY NIGHT...STEEP MIDLEVEL LAPSE RATES AND MODERATE ELEVATED INSTABILITY WILL SUPPORT PRIMARILY ISOLATED HAIL WITH THE STRONGER STORMS. ...SRN APPALACHIANS/SC/ERN GA... THE AIR MASS IS EXPECTED TO BECOME MODERATELY UNSTABLE BY AFTERNOON WITH TSTMS DEVELOPING ALONG AND S OF THE COLD FRONT MOVING THROUGH THIS REGION. WEAK DEEP LAYER SHEAR WILL RESULT IN GENERALLY PULSE-TYPE STORMS WITH AN ATTENDANT THREAT FOR ISOLATED STRONG WIND GUSTS AND/OR SOME HAIL. ..PETERS/ROGERS.. 04/02/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z