If you are looking for fresh snow by Christmas morning or are curious about potential travel disruptions, the best chances for at least 1" of new snowfall early this week exist across the mountainous West, Great Lakes, and Northeast. Otherwise, temperatures this last full week of December will average above normal for much of the lower 48 states. Read More >
SPC AC 141625 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1125 AM CDT TUE OCT 14 2014 VALID 141630Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SOUTHEAST AND SRN/CNTRL APPALACHIANS... ...SUMMARY... THUNDERSTORMS WITH LOCALLY DAMAGING WIND AND ISOLATED TORNADOES MAY OCCUR THROUGH THIS EVENING OVER PARTS OF THE CENTRAL AND SOUTHERN APPALACHIANS...THE CAROLINAS...GEORGIA...AND NORTHERN FLORIDA. AFTERNOON STORMS WITH MARGINALLY SEVERE HAIL AND STRONG GUSTS ALSO MAY OCCUR FROM PARTS OF THE MIDWEST SOUTHEAST INTO THE MID-OHIO VALLEY. ...SYNOPTIC SETUP... ELONGATED MO-IL TROUGH SHOULD CONTINUE SLOWLY E THROUGH EARLY WED AS UPSTREAM TROUGH REACHES THE PACIFIC NW. LEAD SHORTWAVE IMPULSE WITHIN THE MO-IL SYSTEM...NOW OVER CNTRL IL...SHOULD MOVE NNE INTO LWR MI BY THIS EVE...WHILE ARKLATEX SHORTWAVE IMPULSE CONTINUES E INTO AL/E TN. TO THE EAST...RIDGE WILL FURTHER AMPLIFY OVER THE WRN ATLANTIC. AT LWR LVLS...SFC LOW NOW N OF ST LOUIS SHOULD DRIFT NE TO NEAR GRAND RAPIDS THIS EVE AND BECOME STNRY AS TRAILING OCCLUDED/COLD FRONT ADVANCES NE/E ACROSS THE OH AND TN VLYS. FARTHER E...EXPECT WEAK FRONT NOW EXTENDING FROM WRN VA SSE TO OFF THE SC CST TO EDGE ONLY SLOWLY E THROUGH THE PERIOD. ...NRN FL/SRN GA THIS TODAY... BROKEN SQLN NOW EXTENDING FROM SW GA SSW INTO THE ERN GULF OF MEXICO IS LOCATED RELATIVELY CLOSE TO ASSOCIATED COLD FRONT. LARGE-SCALE ASCENT WILL BE NEUTRAL-TO-WEAK AS ARKLATEX SHORTWAVE IMPULSE REMAINS WELL TO THE WEST OF THE REGION UNTIL LATE IN THE DAY. NEVERTHELESS...SFC HEATING WILL SUPPORT AT LEAST MODEST DIURNAL DESTABILIZATION OF VERY MOIST /2-INCH PW/ LOW-LVL ENVIRONMENT AMIDST 35-40 SSWLY DEEP SHEAR. THIS SETUP MAY SUPPORT SOME INTENSIFICATION AND OR RE-DEVELOPMENT OF THE STORMS DURING THE AFTN...WITH AN ASSOCIATED RISK FOR LOCALLY DMGG WIND AND POSSIBLY A TORNADO OR TWO EWD TOWARD THE FL-GA ATLANTIC CST /REF WW 547/. ...NRN GA/UPSTATE CAROLINAS NWD INTO CNTRL APPALACHIANS TODAY/TNGT... NRN PART OF SAME SQLN AFFECTING S GA AND THE FL PANHANDLE HAS PROGRESSED COMPARATIVELY FARTHER E OF ASSOCIATED COLD FRONT AND UPR-LVL SUPPORT. SQLN CLOUD DEBRIS WILL LIMIT SFC HEATING...AND MORNING UPR AIR DATA SUGGEST THAT WEAK WARMING WILL OCCUR OVER THE REGION AT MID-LVLS. BUT GIVEN VERY STRONG /50-60 KTS AT 700 MB/...DEEP UNIDIRECTIONAL SLY FLOW ON ERN SIDE OF SLOWLY-PROGRESSIVE LARGE-SCALE TROUGH...EVEN SFC MODEST HEATING COULD PROMOTE SUFFICIENT UPDRAFT STRENGTHENING TO YIELD A RISK FOR LOCALLY DMGG WIND AND POSSIBLY A COUPLE TORNADOES. THIS RISK COULD REACH NWD FROM NE GA/UPSTATE SC INTO PARTS OF TN...ERN KY...VA...AND WV THROUGH TNGT. ...FAR ERN SC NWD INTO CNTRL VA TODAY/TNGT... WEAK...PREVIOUSLY MENTIONED N-S FRONT WILL SERVE AS A FOCUS FOR LOW-LVL CONFLUENCE/POTENTIAL STORM DEVELOPMENT TODAY FROM FAR ERN SC THROUGH CNTRL NC INTO CNTRL VA. WHILE WEAK WARM ADVECTION IS EXPECTED OVER THE REGION AT MID-LVLS...AND FORCING FOR ASCENT WILL BE MINIMAL...SSWLY DEEP SHEAR WILL STRENGTHEN WITH THE CONTINUED EWD MOTION OF MO-IL UPR TROUGH. GIVEN 40-45 KT SLY LOW-LVL FLOW ALREADY PRESENT OVER THE REGION...AND SLIGHTLY-BACKED NEAR-SFC WINDS NEAR FRONT...ANY INTENSIFYING STORMS ALONG THE BOUNDARY COULD POSE A CONDITIONAL RISK FOR LOCALLY DMGG WIND AND PERHAPS A TORNADO...ESPECIALLY LATER THIS AFTN/EARLY TNGT. ...NRN IL-IND-SW MI SSE INTO MID-OH VLY THIS AFTN/EVE... SATELLITE SUGGESTS THAT AT LEAST POCKETS OF ENHANCED SFC HEATING WILL OCCUR ALONG/AHEAD OF OCCLUDED/COLD FRONT OVER PARTS OF THE MIDWEST/OH VLY TODAY AND NEAR ASSOCIATED SFC LOW. RELATIVE TO YESTERDAY...SOMEWHAT COLDER AIR ALOFT WILL OVERLIE NRN PARTS OF THE PRE-FRONTAL WARM SECTOR. THIS SETUP COULD SUPPORT A CONDITIONAL RISK FOR DIURNALLY-DRIVEN STORMS CAPABLE OF MARGINALLY SVR HAIL/LOCALLY DMGG WIND AND PERHAPS A BRIEF TORNADO INTO EARLY TNGT. ..CORFIDI/DARROW.. 10/14/2014 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z |