Jul 19, 2012 2000 UTC Day 1 Convective Outlook | |
Updated: Thu Jul 19 20:04:30 UTC 2012 | |
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic |
---|
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 192000 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CDT THU JUL 19 2012 VALID 192000Z - 201200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE OH VALLEY/MID-SOUTH/CENTRAL APPALACHIANS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL PORTION OF THE NRN PLAINS... ...OH VALLEY/MID-SOUTH/CENTRAL APPALACHIANS... DAMAGING WIND/SOME SEVERE HAIL POTENTIAL WILL CONTINUE INTO EARLY EVENING WITH AN MCS ACROSS EASTERN KY/NEARING THE CENTRAL APPALACHIANS...AND SPATIAL ADJUSTMENTS HAVE BEEN MADE TO THE SLIGHT RISK ACROSS PORTIONS OF THE REGION. OTHER SEVERE TSTMS WILL CONTINUE TO DEVELOP FARTHER WEST ESPECIALLY ACROSS PORTIONS OF INDIANA AND ADJACENT PARTS OF KY/OH. DAMAGING WINDS/SEVERE HAIL REMAIN PRIMARY HAZARDS...BUT A BRIEF TORNADO THREAT MAY EXIST ACROSS AREAS SUCH AS CENTRAL INDIANA IN VICINITY OF OUTFLOW BOUNDARY. REFERENCE MESOSCALE DISCUSSION 1502 AND WATCHES 495/496 FOR ADDITIONAL SHORT-TERM INFORMATION. OTHERWISE...THE SLIGHT RISK WAS ALSO EXPANDED SOUTHWESTWARD ACROSS PORTIONS OF THE MID-SOUTH. ...ELSEWHERE... NO CHANGES...SEE PRIOR DISCUSSION BELOW AND MESOSCALE 1501 REGARDING PORTIONS OF THE DAKOTAS/MN. ..GUYER.. 07/19/2012 .PREV DISCUSSION... /ISSUED 1126 AM CDT THU JUL 19 2012/ ...MID/LWR OH VLY... LATEST MESOANALYSIS PLACES A 1012 MB LOW OVER NRN IL WITH A FRONT DRAPED EWD INTO THE NRN MID-ATLANTIC REGION AND WWD INTO KS. THE LOW WILL MOVE TO VCNTY KCVG BY FRIDAY MORNING WHILE THE TRAILING FRONT MOVES INTO THE MID-SOUTH/SRN PLAINS. AIR MASS ALONG/S OF THE FRONT WILL REMAIN VERY MOIST WITH PRECIPITABLE WATER VALUES IN EXCESS OF 1.75 INCHES. MULTI-LAYERED CLOUDS WILL MITIGATE STRONG DESTABILIZATION ACROSS THE UPR OH VLY. BUT...AREAS TO THE SW FROM SWRN OH/IND AND INTO THE MID-SOUTH WILL EXPERIENCE STRONG INSOLATION WITH MLCAPES TO 2500 J/KG. TSTMS ARE EXPECTED TO GRADUALLY INCREASE ALONG BOTH THE FRONT AND RESIDUAL BOUNDARIES TIED TO OUTFLOW AND DIFFERENTIAL HEATING FROM THE MID-OH VLY SWWD INTO SERN MO THIS AFTN. CURRENT BLEND OF VWP AND FCST HODOGRAPHS INDICATE THAT WNW BULK SHEAR WILL REMAIN MODEST AT BEST...AROUND 30 KTS. HOWEVER... GIVEN OVERALL INSTABILITY...MULTICELL STORM CLUSTERS WILL BRIEFLY ORGANIZE INTO FORWARD-PROPAGATING SYSTEMS AND PERHAPS BRIEF SUPERCELLS GIVING DMGG WIND GUSTS AND HAIL. STORMS MAY PERSIST INTO TONIGHT BUT WITH DECREASING SVR THREATS. SMALL MCS OR TWO WILL BE MOST LIKELY VCNTY KY/WV/ERN TN. FARTHER E...SVR THREAT MAY BE A BIT LESS ORGANIZED/MORE SPORADIC EWD ACROSS MOUNTAINS TO THE MID ATLANTIC CST. SCTD STG TO OCCASIONALLY SVR STORMS SHOULD...NEVERTHELESS...FORM ALONG AFOREMENTIONED BOUNDARIES. CONCENTRATED MULTICELLS COULD YIELD LOCALLY DMGG WIND AND MARGINALLY SVR HAIL INTO THIS EVE. ...NRN PLAINS... ELEVATED TSTMS WERE ONGOING LATE THIS MORNING OVER ND/SD AMIDST WEAK LOW/MID-LVL WARM ADVECTION. THESE STORMS MAY PRODUCE SOME HAIL...BUT MAIN CONDITIONAL SVR THREAT WILL EVOLVE THIS AFTN/EVE. ON THE LARGER SCALE...BUILDING HEIGHTS/STRENGTHENING EML WOULD ARGUE AGAINST SFC-BASED TSTM DEVELOPMENT AS PARCELS FAIL TO REACH THEIR LFC/S. HOWEVER...RICH BOUNDARY LAYER MOISTURE AND MAINTENANCE OF CONVERGENCE ALONG THE LEE TROUGH WILL LIKELY BE SUFFICIENT FOR A COUPLE STORMS OVER CNTRL/ERN ND BY LATE THIS AFTN. THIRTY-35 KT 0-8KM SHEAR AND MAGNITUDE OF MID-LVL LAPSE RATES...ON THE ORDER OF 8 DEG C PER KM...WILL BE SUFFICIENT FOR SUPERCELLS AND MULTICELL CLUSTERS GIVING VERY LARGE HAIL AND DMGG WIND GUSTS. A TORNADO OR TWO CANNOT BE RULED OUT IN THE RED RIVER VLY AND ADJACENT ERN ND. OVERNIGHT...A SSE PROPAGATING CLUSTER OF STORMS...WILL CLIP PARTS OF NWRN MN AND NERN SD WITH AT LEAST LOW-END RISKS FOR LARGE HAIL AND PERHAPS HIGH WINDS. ...INTERIOR PAC NW... MUCH LIKE YESTERDAY...WDLY SCTD TO LOCALLY SCTD AFTN/EVE TSTMS EXPECTED WITH SFC HEATING IN ZONE OF MODERATE MOISTURE OVER HIGHER TERRAIN IN NE QUADRANT OFF OFFSHORE LOW...FROM THE ORE CASCADES ENE INTO ERN WA/WRN ID. ISOLD SVR HAIL/GUSTS MAY OCCUR. SOME OF THE STORMS MAY PERSIST/REDEVELOP THROUGH EARLY FRI AS UPR LVL DIFLUENCE INCREASES WITH THE NEWD ACCELERATION OF THE OFFSHORE LOW. GIVEN 40-50 KT CLOUD LAYER SHEAR AND CONTINUED NE ADVANCE OF UPR TROUGH...A FEW OF THE STORMS COULD REMAIN LOCALLY STRONG TO SVR. ...SERN U.S. THIS AFTN... SCTD TO LOCALLY NUMEROUS TSTMS IN CLUSTERS AND LOOSELY ORGANIZED BANDS LIKELY WILL FORM AGAIN TODAY OVER MUCH OF THE SERN STATES. AREA SOUNDINGS DO...HOWEVER...APPEAR SOMEWHAT STABILIZED RELATIVE TO YESTERDAY...LIKELY REFLECTING SIZABLE OVERTURNING THAT OCCURRED THERE. AFOREMENTIONED WEAK UPR CIRCULATIONS WILL ONCE AGAIN LARGELY GOVERN WHERE CONVECTION BECOMES MOST CONCENTRATED. A FEW STORMS MAY YIELD LOCALLY DMGG WIND. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z