Issued by NWS Indianapolis, IN
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000 FXUS63 KIND 222309 AFDIND AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 710 PM EDT WED OCT 22 2008 .AVIATION...DISCUSSION FOR 230000Z TAF ISSUANCE. NO SIG CLD COVER BLW 050...VSBYS UNRESTRICTED...SFC WNDS BLW 15 KTS THRU 231200Z. && .DISCUSSION... FORECAST FOCUS IS ON TEMPS EARLY THEN ON CHANCES FOR RAIN INTO THE WEEKEND. AT 18Z SKIES WERE MOSTLY CLEAR ACROSS THE FORECAST AREA /FA/ WITH AN UPPER RIDGE AND SFC HIGH IN CONTROL OF THE WEATHER. VERY DRY AIR WAS IN PLACE ACROSS THE FA WITH DEWPOINTS DIPPING INTO THE UPPER TEENS IN SPOTS. AN UPPER LOW WAS SPINNING ACROSS NE. MODELS ARE COMING INTO BETTER AGREEMENT WITH TIMING AND PLACEMENT OF UPCOMING PRECIPITATION. STILL WENT CLOSER TO GFS WITH ITS BETTER CONSISTENCY OF LATE IN HANDLING OF THIS SYSTEM. VERY DRY AIR WILL CONTINUE ACROSS THE FA TONIGHT WITH EASTERLY FLOW THROUGH A GOOD PART OF THE ATMOSPHERE. THIS SHOULD HELP ERODE MID AND HIGH CLOUDS AS THEY COME EAST TOWARD THE FA. WILL PROBABLY END UP WITH MOSTLY CLEAR SKIES FOR MOST OF THE NIGHT. WITH SUCH DRY AIR AM A LITTLE CONCERNED ABOUT LOW TEMPS TONIGHT...BUT WITH WINDS STAYING UP THE ATMS WILL REMAIN MIXED. THUS CONDITIONS ARE NOT GREAT FOR FROST OR BELOW FREEZING TEMPS...WITH THE EXCEPTION OF WELL SHELTERED LOW LYING AREAS OF COURSE. WITH THE DRY ATMS WILL TREND TOWARD THE COOLER SIDE OF GUIDANCE FOR MINS TONIGHT IN THE MID TO UPPER 30S FOR THE MOST PART. CLOUDS WILL INCREASE AS SYSTEM APPROACHES ON THU. STRONG WARM ADVECTION IS NOT PRESENT AT THE SFC BUT WARM ADVECTION WILL BE OCCURRING ALOFT. SHOULD BE ENOUGH MIXING FOR TEMPS TO REACH THE 60S AS A BLEND OF MOS SUGGESTS. LOW LEVEL WINDS WILL GRADUALLY BECOME SOUTHERLY THU NIGHT AND START TO BRING IN MOISTURE. BOTH GFS/NAM NOW AGREE THAT PRECIP WILL BE POSSIBLE ACROSS MOST OF THE FA BEFORE 12Z FRI. BOTH QVECTOR CONVERGENCE AND FRONTOGENETICAL FORCING INCREASE ACROSS THE ENTIRE FA BY 12Z. WILL PUT LIKELY POPS ACROSS SWRN FA WHERE BEST MOISTURE AND FORCING WILL BE AND CHANCE POPS ELSEWHERE. AS UPPER LOW MOVES INTO THE AREA STARTING FRI ALONG WITH A FRONT...FORCING FROM THESE WILL PRODUCE PRECIP ACROSS THE FA. WILL GO CATEGORICAL POPS MOST AREAS. DRY SLOT MAY WORK IN FOR FRI AFTN BUT TOO FAR OUT TO GET THAT SPECIFIC IN TIMING. AS UPPER LOW MOVES ACROSS ON SAT CHANCE POPS WILL CONTINUE WITH VERY COLD AIR ALOFT LEADING TO INSTABILITY. ANOTHER EVEN COLDER SURGE OF AIR WILL MOVE IN STARTING SUNDAY...SO HAVE ADDED LOW POPS WITH THIS FRONT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AVIATION...JAS PUBLIC...CS