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Convective Outlooks
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» From the Storm Prediction Center
SPC - No watches are valid as of Mon Nov 24 16:32:01 UTC 2014
No watches are valid as of Mon Nov 24 16:32:01 UTC 2014.

SPC MD 1951
MD 1951 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL AND EASTERN OHIO...WESTERN PENNSYLVANIA...NORTHERN WEST VIRGINIA PANHANDLE...SOUTHWEST NEW YORK
MESOSCALE DISCUSSION 1951 NWS STORM PREDICTION CENTER NORMAN OK 0917 AM CST MON NOV 24 2014 AREAS AFFECTED...PORTIONS OF CENTRAL AND EASTERN OHIO...WESTERN PENNSYLVANIA...NORTHERN WEST VIRGINIA PANHANDLE...SOUTHWEST NEW YORK CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 241517Z - 241745Z PROBABILITY OF WATCH ISSUANCE...5 PERCENT SUMMARY...LOW-TOPPED CONVECTION...WITH LITTLE TO NO LIGHTNING...WILL CROSS PORTIONS OF THE LOWER GREAT LAKES AND OHIO VALLEY REGION INTO THE AFTERNOON HOURS AND WILL BE CAPABLE OF PRODUCING GUSTY WINDS AS IT SPREADS NE. A WW WILL NOT BE NEEDED. DISCUSSION...QUASI-LINEAR CONVECTIVE SEGMENTS CONTINUE SPREADING NE WITHIN BROADLY CONFLUENT FLOW PRECEDING A FRONT ANALYZED FROM CENTRAL LOWER MI TO NWRN KY. AS THE SECOND VORT MAX IN A SERIES OF THREE TRAINING MIDLEVEL PERTURBATIONS LIFTS INTO SWRN ONTARIO...STRONGER ASCENT AND THE AFOREMENTIONED SFC FEATURES WILL PROGRESS RAPIDLY NEWD...WITH CONVECTION SPREADING NE INTO THE AFTERNOON -- REACHING COLUMBUS AND CLEVELAND IN THE NEXT HOUR OR SO. HOWEVER...AS STRONGER MID-LEVEL DCVA SPREADS NE OF THE INTERNATIONAL BORDER...CONVECTION WILL CONTINUE TO TREND TOWARD A LOW-TOPPED REGIME. THIS IS EVIDENCED BY THE RECENT...RAPID DECREASE IN LIGHTNING COVERAGE IN NWRN/N-CNTRL OHIO...ALONG WITH A NOTABLE SUBSIDENCE INVERSION SAMPLED BY THE 12Z WILMINGTON OHIO RAOB JUST BELOW THE 700-MB LEVEL. THE PRESENCE OF PRE-FRONTAL DEWPOINTS IN THE LOWER 50S WILL SUPPORT A DEARTH OF BUOYANCY -- MLCAPE OF 100-300 J/KG WITH EL TEMPERATURES WARMER THAN -20C. HOWEVER...VERY STRONG LOW-LEVEL FLOW -- E.G. 60-70 KT SWLYS SAMPLED BY THE WILMINGTON AND CLEVELAND OHIO VWPS AT 1 KM AGL WILL ENHANCE CONVECTIVE MOMENTUM TRANSPORT WITH THE POTENTIAL FOR STRONG TO PERHAPS LOCALLY MARGINALLY SVR WIND GUSTS INTO THE AFTERNOON. THE PAUCITY OF BUOYANCY/DEARTH OF MOISTURE...AND LAGGING STRONGER FRONTAL/BAROCLINIC CIRCULATIONS...SHOULD PRECLUDE A GREATER SVR-TSTM RISK FROM OCCURRING. ..COHEN/THOMPSON.. 11/24/2014 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BUF...CTP...PBZ...RLX...CLE...ILN... LAT...LON 41298251 41618170 41978056 42407931 40598014 39728192 39588338 40298333 41298251 Read more

SPC Nov 24, 2014 1300 UTC Day 1 Convective Outlook
SPC 1300Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0653 AM CST MON NOV 24 2014 VALID 241300Z - 251200Z ...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE SOUTHEAST... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS A PORTION OF THE OH VALLEY... ...SUMMARY... A FEW STRONG TO SEVERE WIND GUSTS ARE POSSIBLE WITH THUNDERSTORMS MOVING ACROSS THE OHIO VALLEY THIS MORNING. OVER THE SOUTHEAST...ISOLATED SEVERE STORMS ARE POSSIBLE TODAY INTO TONIGHT WITH DAMAGING WINDS BEING THE PRIMARY HAZARD. ...SYNOPSIS... A LONG-WAVE TROUGH INITIALLY ENCOMPASSING MUCH OF THE CONUS WILL SHORTEN IN WAVELENGTH AND AMPLIFY DUE IN PART TO THE EWD DEVELOPMENT OF AN UPSTREAM RIDGE OVER THE NERN PACIFIC. WITHIN THIS LARGE-SCALE PATTERN...A SIGNIFICANT /100-120 KT/ JET STREAK AT 500 MB WILL DEVELOP FROM THE OH VALLEY INTO NERN U.S. IN TANDEM WITH A LOW-AMPLITUDE SHORT-WAVE TROUGH. ON ITS HEELS...PHASING OF SEPARATE VORTICITY MAXIMA WILL OCCUR OVER THE SRN ROCKIES INTO LOWER RIO GRANDE VALLEY...CONTRIBUTING TO LOWERING MID-LEVEL HEIGHTS OVER CNTRL AND SRN TX. AT THE SURFACE...A DEEP CYCLONE OVER THE U.P. OF MI WILL DEVELOP NEWD THROUGH WRN INTO NRN QUEBEC WHILE A TRAILING COLD FRONT SURGES EWD THROUGH THE OH VALLEY AND LOWER GREAT LAKES. THE SWRN EXTENSION OF THIS COLD FRONT WILL MOVE MORE SLOWLY EWD ACROSS THE GULF COAST STATES TOWARD THE SERN ATLANTIC COAST. ...NERN GULF COAST TO THE COASTAL CAROLINAS TODAY AND TONIGHT... A SW-NE-ORIENTED BAND OF TSTMS HAS EVOLVED OVERNIGHT FROM THE CNTRL FL PNHDL INTO SWRN GA ALONG AN APPARENT CONFLUENCE ZONE WITHIN THE PRE-FRONTAL WARM SECTOR. 12Z SOUNDINGS AT TLH AND CHS REVEALED THE PRESENCE OF A VERY MOIST BOUNDARY LAYER WITH LOWEST 100-MB MEAN MIXING RATIOS OF 14-15 G/KG. HOWEVER...MID-LEVEL LAPSE RATES WERE QUITE POOR WHICH WILL LIMIT THE DEGREE OF AIR MASS DESTABILIZATION AND THE POTENTIAL FOR VIGOROUS UPDRAFT GROWTH. NONETHELESS...LATEST MODEL GUIDANCE SUGGESTS THAT THE ONGOING STORMS SHOULD PERSIST TODAY...GRADUALLY EXPANDING NEWD ALONG THE CAROLINA COASTAL PLAIN BY AFTERNOON AS THE BOUNDARY LAYER WARMS AND GRADUALLY DESTABILIZES. THE STRONGEST STORMS WILL BE CAPABLE OF LOCALLY DAMAGING WIND GUSTS AND PERHAPS A WEAK TORNADO OWING TO THE PRESENCE OF A RELATIVELY STRONG UNIDIRECTIONAL WIND FIELD. STORMS MAY TEMPORARILY WEAKEN THIS EVENING PRIOR TO RE-INTENSIFYING LATER TONIGHT AS LOW-LEVEL CONVERGENCE/ASCENT IS ENHANCED BY THE ARRIVAL OF THE COLD FRONT. THESE LATE-NIGHT STORMS WILL ALSO BE CAPABLE OF A FEW STRONG WIND GUSTS. ...OH VALLEY THIS MORNING... MULTIPLE SHORT CONVECTIVE LINE-SEGMENTS AND WEAK SUPERCELLS ARE IN PROGRESS AS OF 12Z OVER CNTRL AND SRN IND WITH THIS ACTIVITY SITUATED ALONG THE IMMEDIATE CYCLONIC SIDE OF THE 100+ KT MID-LEVEL JET STREAK AND WITHIN A ZONE A DCVA ASSOCIATED WITH A VORTICITY MAXIMUM OVER CNTRL IL. STRONG TO SEVERE CONVECTIVE WIND GUSTS HAVE RECENTLY BEEN OBSERVED AS HAS SOME MID-LEVEL UPDRAFT ROTATION. DESPITE THE PRESENCE OF AN ONLY WEAKLY UNSTABLE AIR MASS /REF. 12Z ILN SOUNDING/...THE COMBINATION OF A VERY STRONG WIND FIELD AND AT LEAST MODEST LARGE-SCALE FORCING FOR ASCENT WILL BE SUFFICIENT TO SUSTAIN SOME EMBEDDED BOWING/LEWP STRUCTURES --AND AN ASSOCIATED WIND DAMAGE THREAT-- THROUGH THIS MORNING. ..MEAD/MOSIER.. 11/24/2014 Read more

SPC Nov 24, 2014 1630 UTC Day 1 Convective Outlook
SPC 1630Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1023 AM CST MON NOV 24 2014 VALID 241630Z - 251200Z ...THERE IS A MRGL RISK OF SVR TSTMS THIS AFTERNOON FROM THE CENTRAL FL PANHANDLE NEWD TO THE ERN CAROLINAS... ...SUMMARY... ISOLATED STRONG TO SEVERE WIND GUSTS ARE POSSIBLE WITH THUNDERSTORMS TODAY FROM THE FLORIDA PANHANDLE TO THE EASTERN CAROLINAS. OTHER STRONG WINDS WILL BE POSSIBLE WITH CONVECTIVE SHOWERS FROM CENTRAL AND NORTHEAST OHIO TO NORTHWEST PENNSYLVANIA AND WESTERN NEW YORK. ...SYNOPSIS... A SERIES OF EMBEDDED SPEED MAXIMA WILL ROTATE THROUGH THE LARGE-SCALE TROUGH THAT IS NOW ESTABLISHED OVER MOST OF THE CONUS. THE STRONGEST JET STREAK WILL TRANSLATE NEWD FROM THE UPPER OH VALLEY TO THE SAINT LAWRENCE VALLEY THROUGH THE AFTERNOON...WHILE A SEPARATE WAVE MOVES ESEWD FROM THE SRN ROCKIES TO THE SRN PLAINS. THE PRIMARY SURFACE CYCLONE HAS ALREADY DEVELOPED NNEWD TO THE N OF LAKE HURON...WHILE THE TRAILING COLD FRONT MOVES EWD ACROSS THE OH VALLEY. THE SRN EXTENT OF THIS FRONT WILL MOVE MUCH SLOWER TO THE E ACROSS AL/GA/SRN APPALACHIANS...IN RESPONSE TO THE APPROACH OF THE UPSTREAM TROUGH OVER THE SRN PLAINS. ...UPPER OH VALLEY TO THE LOWER GREAT LAKES TODAY... ASCENT IN THE LEFT EXIT REGION OF THE PRIMARY UPPER JET STREAK...IN CONJUNCTION WITH LOW-LEVEL LIFT ALONG A SURFACE COLD FRONT...IS SUPPORTING A BAND OF LOW-TOPPED CONVECTION ACROSS CENTRAL/N CENTRAL OH. THE DEPTH AND VIGOR OF THIS CONVECTION HAS BEEN DIMINISHING OVER THE PAST 1-2 HOURS...AND THE RISK FOR ADDITIONAL LIGHTNING HAS DECREASED. STILL...DOWNWARD MOMENTUM TRANSFER WITH SHALLOW CONVECTION COULD SUPPORT ISOLATED STRONG GUSTS THROUGH THIS AFTERNOON ACROSS NE OH...NW PA...AND WRN NY. ...NE GULF COAST TO THE SE ATLANTIC COAST THROUGH TONIGHT... A BAND OF PRE-FRONTAL CONVECTION IS ONGOING ALONG THE GRADIENT IN LOW-LEVEL MOISTURE/BUOYANCY FROM THE CENTRAL FL PANHANDLE TO SE GA. THOUGH RICH LOW-LEVEL MOISTURE IS PRESENT TO THE E-SE OF THE CONVECTION /BOUNDARY LAYER DEWPOINTS IN THE LOW 70S/...12Z SOUNDINGS REVEALED POOR LAPSE RATE PROFILES FROM THE SURFACE TO ALMOST 500 MB. DEEP-LAYER VERTICAL SHEAR AND BUOYANCY WILL BE SUFFICIENT FOR SOME ORGANIZED CELLS/LINE SEGMENTS WITHIN THE BAND. HOWEVER...LIMITED SURFACE HEATING...POOR LAPSE RATE PROFILES ALOFT...AND A TENDENCY FOR WEAKENING LOW-LEVEL SHEAR WITH TIME SHOULD KEEP THE DAMAGING WIND RISK IN THE MARGINAL CATEGORY. ..THOMPSON/COHEN.. 11/24/2014 Read more

SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1030 AM CST MON NOV 24 2014 VALID 241700Z - 251200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES AND FOOTHILLS OF SRN CA... NO CHANGES TO THE PREVIOUS FORECAST. LOCALLY ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE TODAY ACROSS PORTIONS OF NWRN OK / SRN KS...AS A VERY DRY POST-FRONTAL AIR MASS AND DEEP DIURNAL MIXING RESULT IN BREEZY CONDITIONS AND RH VALUES FALLING INTO THE 15-25 PERCENT RANGE. WHILE THIS AREA HAS BEEN REMOVED TO THE NORTH OF WETTING RAINS OVER THE LAST 1-2 WEEKS...SEASONABLY COOL TEMPERATURES AND MARGINAL WIND SPEEDS PRECLUDE THE NEED FOR AN ELEVATED DELINEATION. ..PICCA.. 11/24/2014 .PREV DISCUSSION... /ISSUED 0250 AM CST MON NOV 24 2014/ ...SYNOPSIS... UPPER TROUGH COVERING THE CONUS WILL SHIFT EWD AND AMPLIFY WHILE UPPER RIDGING SPREADS INTO SRN/CNTRL CA. AT THE SURFACE...DEEP LOW WILL MOVE FROM THE GREAT LAKES NEWD THROUGH NERN ONTARIO AND INTO WRN QUEBEC AS A TRAILING COLD FRONT PUSHES ACROSS THE ERN CONUS. HIGH PRESSURE WILL SHIFT SEWD FROM THE GREAT BASIN TOWARDS THE FOUR CORNERS. ...COASTAL RANGES AND FOOTHILLS OF SRN CA... REGIONAL OBSERVATIONS REVEAL THAT GENERALLY POOR RH RECOVERY IS ONGOING WITH NUMEROUS SITES REPORTING RH VALUES BELOW 15 PERCENT. OFFSHORE GRADIENT IS EXPECTED TO BE LOWER THROUGHOUT THE DAY THAN YESTERDAY WITH SUSTAINED NLY/NELY WINDS AROUND 20 MPH WITH GUSTS UP TO 40 MPH THROUGH THE FAVORED CANYONS AND PASSES. RH VALUES WILL REMAIN BELOW 15 PERCENT AND ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED DURING THE DAY. AFTER 00Z/TUE... OFFSHORE GRADIENT IS EXPECTED TO INCREASE AS COLD AIR MOVES INTO THE ERN GREAT BASIN AND FOUR CORNERS...STRENGTHENING SURFACE HIGH PRESSURE THROUGHOUT THE REGION. SUSTAINED WIND SPEEDS AFTER 00Z/TUE COULD APPROACH 30 MPH WITH GUSTS OVER 50 MPH. THESE STRONG WINDS COUPLED WITH POOR OVERNIGHT RH RECOVERY AND DRY FUELS WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS AFTER 00Z/TUE. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more

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