Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Storm Prediction Center Aug 21, 2014 2000 UTC Day 1 Convective Outlook 12/12/14 12:36 PM Aug 21, 2014 2000 UTC Day 1 Convective Outlook Updated: Thu Aug 21 20:05:54 UTC 2014 ( | ) Probabilistic to Categorical Outlook Conversion Table Categorical Graphic Risk SLIGHT Area (sq. mi.) 241,344 Area Pop. 48,895,272 Some Larger Population Centers in Risk Area Chicago, IL...Philadelphia, PA...Indianapolis, IN...Columbus, OH...Baltimore, MD... Probabilistic Tornado Graphic http://tornado.sfsu.edu/geosciences/classes/m302/ConvectiveOutlooks/SlightRisk/SlightRisk_August_21_2014.html Page 1 of 5 Storm Prediction Center Aug 21, 2014 2000 UTC Day 1 Convective Outlook 12/12/14 12:36 PM 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. Tornado Risk 2% Area (sq. mi.) 106,089 Area Pop. 33,756,087 Some Larger Population Centers in Risk Area Chicago, IL...Philadelphia, PA...Baltimore, MD...Milwaukee, WI...Washington, DC... Probabilistic Damaging Wind Graphic http://tornado.sfsu.edu/geosciences/classes/m302/ConvectiveOutlooks/SlightRisk/SlightRisk_August_21_2014.html Page 2 of 5 Storm Prediction Center Aug 21, 2014 2000 UTC Day 1 Convective Outlook 12/12/14 12:36 PM 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. Wind Risk 15 % 5% Area (sq. mi.) 240,738 442,774 Area Pop. 48,757,210 53,749,928 Some Larger Population Centers in Risk Area Chicago, IL...Philadelphia, PA...Indianapolis, IN...Columbus, OH...Baltimore, MD... Phoenix, AZ...Atlanta, GA...Minneapolis, MN...Pittsburgh, PA...Toledo, OH... Probabilistic Large Hail Graphic http://tornado.sfsu.edu/geosciences/classes/m302/ConvectiveOutlooks/SlightRisk/SlightRisk_August_21_2014.html Page 3 of 5 Storm Prediction Center Aug 21, 2014 2000 UTC Day 1 Convective Outlook 12/12/14 12:36 PM 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. Hail Risk 15 % 5% Area (sq. mi.) 179,964 365,724 Area Pop. 39,475,100 51,652,352 Some Larger Population Centers in Risk Area Chicago, IL...Philadelphia, PA...Indianapolis, IN...Baltimore, MD...Washington, DC... Phoenix, AZ...Columbus, OH...Milwaukee, WI...Mesa, AZ...Minneapolis, MN... SPC AC 212005 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0305 PM CDT THU AUG 21 2014 VALID 212000Z - 221200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY INTO THE OH VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PART OF THE MID-ATLANTIC STATES... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF SERN CA INTO SWRN AZ... ...SUMMARY... SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED FROM PORTIONS OF THE UPPER MISSISSIPPI VALLEY INTO THE OHIO VALLEY AND CENTRAL APPALACHIANS. DAMAGING WINDS AND LARGE HAIL ARE THE PRIMARY THREATS WITH THIS ACTIVITY. STORMS WITH LARGE HAIL AND STRONG WINDS WILL ALSO BE POSSIBLE ACROSS THE LOWER COLORADO RIVER VALLEY. SCATTERED STRONG TO SEVERE STORMS WILL ALSO REMAIN POSSIBLE INTO THE EARLY EVENING ACROSS PORTIONS OF THE MIDDLE ATLANTIC STATES FROM SOUTHEAST PENNSYLVANIA INTO NORTHERN AND CENTRAL MARYLAND...WASHINGTON D.C. TO DELAWARE AND SOUTHERN NEW JERSEY. ...MID-ATLANTIC STATES... A SLIGHT RISK HAS BEEN INTRODUCED ACROSS THIS REGION AND INCLUDES THE METRO AREAS OF PHILADELPHIA...BALTIMORE AND THE DISTRICT OF COLUMBIA. VAD WINDS SHOWED SOME STRENGTHENING OF WLY 500 MB WINDS /AT 35 KT/ ENHANCING BULK SHEAR FOR STORM ORGANIZATION EWD FROM AND INCLUDING SRN PA AND NRN MD. MODERATE INSTABILITY ACROSS THIS REGION COMBINED WITH THE STRONGER BULK SHEAR IS EXPECTED TO SUPPORT ADDITIONAL STRONG TO SEVERE STORMS DEVELOPING AND SPREADING SEWD. ...SRN MN/WRN WI... LOW-LEVEL STRATUS CLOUDS OVER PORTIONS OF CENTRAL MN INCLUDING THE NRN TWIN CITIES METRO AND WEST CENTRAL WI WILL TEND TO INHIBIT SURFACE HEATING/DESTABILIZATION THROUGH THE REST OF THE AFTERNOON. TSTMS REMAIN POSSIBLE PER 4KM NAM AND 4KM NSSL MODELS WITHIN THE WARM SECTOR IN SRN MN. THIS OUTLOOK HAS SHIFTED THE NRN PORTION OF THE SLIGHT RISK IN SRN MN AND WRN WI SWD A FEW COUNTIES. ...ERN KY/FAR SWRN VA... THE SLIGHT RISK HAS BEEN EXPANDED A LITTLE TO INCLUDE MORE OF SERN KY AND FAR SWRN VA GIVEN CONVECTIVE TRENDS AND SIMILAR VALUES OF MODERATE TO STRONG INSTABILITY PER OBJECTIVE ANALYSES. ...ERN AL AND WRN/CENTRAL GA... STORMS WILL CONTINUE TO DEVELOP ACROSS THESE REGIONS THROUGH THE AFTERNOON TO EARLY EVENING WHERE THE ENVIRONMENT HAS BECOME VERY UNSTABLE /MLCAPE EXCEEDING 3000 J PER KG/. WEAK DEEP LAYER SHEAR WILL TEND TO LIMIT STORM ORGANIZATION...WITH STRONG WIND GUSTS BEING THE PRIMARY THREATS. http://tornado.sfsu.edu/geosciences/classes/m302/ConvectiveOutlooks/SlightRisk/SlightRisk_August_21_2014.html Page 4 of 5 Storm Prediction Center Aug 21, 2014 2000 UTC Day 1 Convective Outlook 12/12/14 12:36 PM THE PRIMARY THREATS. ...REST OF THE FORECAST... NO OTHER SIGNIFICANT CHANGES HAVE BEEN MADE TO THIS OUTLOOK. ..PETERS.. 08/21/2014 .PREV DISCUSSION... /ISSUED 1129 AM CDT THU AUG 21 2014/ ...UPPER MS VALLEY THROUGH THE GREAT LAKES AND OH VALLEY... HEIGHTS WILL RISE AND SHORTWAVE RIDGING WILL BUILD EWD TOWARD THE GREAT LAKES. HOWEVER...SATELLITE DATA AND RUC ANALYSIS SHOW A COUPLE OF VORTICITY MAXIMA...ONE LOCATED OVER WI AND ANOTHER OVER WRN IA. WIDESPREAD CLOUDS AND THUNDERSTORMS DEVELOPING WITHIN ZONE OF WARM ADVECTION CONTINUES FROM IA AND WI THROUGH NRN IL AND SEWD THROUGH OH. CLOUD COVER IS MUCH MORE LIMITED IN WARM SECTOR TO THE SOUTH OF THIS ACTIVITY WHERE DEWPOINTS ARE AROUND 70F. DIABATIC WARMING WILL DESTABILIZE THE BOUNDARY LAYER THIS AFTERNOON WITH MLCAPE FROM 2000-3000 J/KG LIKELY. POTENTIAL EXISTS FOR STORMS TO REDEVELOP AND INTENSIFY LATER OVER THE OH VALLEY TODAY AS MOIST SWLY INFLOW FROM THE DESTABILIZING WARM SECTOR INTERACTS WITH THE NW-SE ORIENTED CONVECTIVELY REINFORCED BAROCLINIC ZONE. STORMS MAY SUBSEQUENTLY EVOLVE INTO CLUSTERS AS THEY DEVELOP SEWD WITH A THREAT FOR ISOLATED DAMAGING WIND AND HAIL. OTHER STRONG TO SEVERE STORMS MAY DEVELOP FARTHER NORTH IN MN NEAR THE WARM FRONT-COLD FRONT INTERSECTION. ...EXTREME SERN CA AND SWRN AZ... PER SATELLITE IMAGERY AND GPS PW DATA...A MOISTURE PLUME ORIGINATING FROM T.S. LOWELL HAS BEEN ENTRAINED INTO THE EASTERN FLANK OF A CLOSED LOW MOVING SLOWLY EAST TOWARD THE LOWER CO RIVER VALLEY. LIFT AND COLDER AIR ALOFT ACCOMPANYING THE MID/UPPER LOW...IN CONCERT WITH DIURNAL HEATING...WILL LIKELY RESULT IN A CORRIDOR OF GREATER DESTABILIZATION AND THUNDERSTORM DEVELOPMENT ACROSS THE LOWER CO RIVER VALLEY LATER TODAY. IN ADDITION TO LOCALLY STRONG WIND GUSTS GIVEN HIGH DCAPE...SPC HAIL MODEL APPLIED TO FORECAST SOUNDINGS FROM THE NAM AND WRF-ARW INDICATE THE POSSIBILITY OF SEVERE HAIL TO AT LEAST 1 INCH IN DIAMETER. WHILE THE AREAL EXTENT OF THE SEVERE STORM THREAT MAY REMAIN CONFINED...ENVIRONMENT APPEARS SUFFICIENT ENOUGH TO WARRANT SLGT RISK 15 PERCENT HAIL/WIND PROBABILITIES. ...MID ATLANTIC AREA... BACKGROUND CYCLONIC FLOW AND WEAK DPVA AMIDST A PLUME OF RELATIVELY HIGH PW SHOULD FOSTER SCATTERED LOOSELY-ORGANIZED THUNDERSTORMS OVER NY/PA AND DELMARVA THIS AFTERNOON. A BELT OF SOMEWHAT STRONGER MID-LEVEL FLOW FORECAST FROM SOUTHEAST NY ACROSS PA/NJ MAY CONTRIBUTE TO SLIGHTLY MORE ORGANIZED/PERSISTENT STORMS IN THESE AREAS. WHILE A COUPLE OF STRONGER CONVECTIVE WIND GUSTS WILL BE POSSIBLE AROUND THE TIME OF PEAK HEATING...WEAK LAPSE RATES AND MODEST INSTABILITY SUGGEST THE SEVERE WIND GUST POTENTIAL SHOULD REMAIN LIMITED. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z http://tornado.sfsu.edu/geosciences/classes/m302/ConvectiveOutlooks/SlightRisk/SlightRisk_August_21_2014.html Page 5 of 5