Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000 FXUS63 KIND 311552 AFDIND AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 1152 AM EDT FRI OCT 31 2014 .UPDATE...
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THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
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&& .SYNOPSIS... ISSUED AT 222 AM EDT FRI OCT 31 2014 A STRONG COLD FRONT IS EXPECTED TO PUSH ACROSS CENTRAL INDIANA THIS AFTERNOON...ALLOWING MUCH COLDER CANADIAN AIR ACROSS CENTRAL INDIANA FOR TONIGHT AND INTO THE FIRST PART OF THE WEEKEND. SOME SHOWERS WILL BE POSSIBLE TODAY AHEAD OF THE FRONT...AND EVEN A FEW LIGHT SNOW SHOWERS WILL BE POSSIBLE IN THE WAKE OF THE FRONT THIS EVENING. BY SATURDAY MORNING...CENTRAL INDIANA WILL HAVE HAD A KILLING FREEZE. COOL HIGH PRESSURE IS EXPECTED OVER THE REGION ON SUNDAY AND INTO MONDAY WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES. BY MONDAY NIGHT AND TUESDAY...WARMER TEMPERATURES ARE EXPECTED TO ARRIVE ON SOUTHERLY WINDS ON THE BACKSIDE OF HIGH PRESSURE...HOWEVER ANOTHER APPROACHING COOL FRONT WILL RESULT IN MORE CHANCES FOR RAIN. && .NEAR TERM /THIS AFTERNOON/...
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ISSUED AT 1152 AM EDT FRI OCT 31 2014 SPEED UP THE MIX WITH SNOW ACROSS OUR NORTHWEST COUNTIES AS MONTICELLO WAS NOW REPORTING LAKE EFFECT SNOW SHOWERS THERE. OTHERWISE...LOWERED INITIAL TEMPERATURES PER OBSERVATIONS. UPDATED THE GRIDS AS WELL AS THE HAZARDOUS WEATHER OUTLOOK TO REFLECT THIS. PREVIOUS DISCUSSION FOLLOWS... SURFACE ANALYSIS EARLY THIS MORNING SHOWS A STRONG AREA OF LOW PRESSURE OVER THE GREAT LAKES WITH A POORLY DEFINED YET STRONG COLD FRONT STRETCHING SOUTH ACROSS EASTERN WISCONSIN...EASTERN ILLINOIS TO THE LOWER MISSISSIPPI RIVER VALLEY. STRONG AND COLD HIGH PRESSURE WAS FOUND OVER THE UPPER MIDWEST. MUCH COLDER AIR WAS FOUND IN THE WAKE OF THE FRONT...WITH TEMPS IN THE 30S AND LOW 40S ACROSS WISCONSIN...IOWA AND MINNESOTA. ALOFT...WATER VAPOR SHOWED A STRONG RIDGE IN PLACE OVER THE ROCKIES AND A DEEP BROAD TROUGH IN PLACE ACROSS THE EASTERN HALF OF THE UNITED STATES. A STRONG UPPER LEVEL DISTURBANCE WAS EMBEDDED IN THE FLOW ALOFT OVER WESTERN LAKE SUPERIOR AND WAS DIVING SOUTHEAST. RADAR SHOWS A FEW SCATTERED RAIN SHOWERS OVER SOUTHERN CENTRAL INDIANA...ALONG WITH A FEW MORE VERY LIGHT RAIN SHOWERS OVER CENTRAL ILLINOIS. GFS AND NAM SUGGEST VERY STRONG COLD AIR ADVECTION TO START SHORTLY AFTER 12Z TODAY WITH 850MB TEMPS FALLING TOWARD -6C BY 00Z SAT. GIVEN THIS WE WILL EXPECT STEADY OR SLOWLY FALLING TEMPERATURES THROUGH THE DAY TODAY. WILL AIM FOR HIGH TEMPS FOR TODAY OCCURRING AT OR SHORTLY AFTER 12Z...AHEAD OF THE FRONT. FURTHERMORE THE STRONG PRESSURE GRADIENT BUILDING ACROSS THE WILL RESULT IN GUSTY NORTH WINDS WITH WIND CHILLS AROUND 30 THIS AFTERNOON AND IN THE MIDDLE 20S TONIGHT. AS FOR PRECIP...LIMITED MOISTURE APPEARS IN PLACE WITH TODAY/S SYSTEM...HOWEVER STRONG FORCING AND DYNAMICS ARE IN PLACE AS THIS SYSTEM PASSES. BEST MOISTURE APPEARS TO BE PASSING NEAR FRONTAL PASSAGE AROUND 12Z. FORECAST SOUNDINGS APPEAR TO DRY OUT LATE THIS MORNING AND THIS AFTERNOON AS NORTHERLY FLOW RESUMES. HOWEVER BY LATE THIS AFTERNOON AND NEAR 00Z A SECOND BATCH OF PRECIP WILL BE POSSIBLE AS THE MODELS SUGGEST THE PREVIOUSLY MENTIONED STRONG UPPER LEVEL DISTURBANCE WILL DIVE ACROSS CENTRAL INDIANA. BY 00Z...FORECAST SOUNDINGS SHOW GOOD SATURATION IN THE LOWER AND MID LEVELS...ALL WHILE AN 850MB JET OF 50+ KNOTS SCREAMS ALOFT. FURTHERMORE BY 00Z FORECAST SOUNDINGS SHOW JUST ABOUT THE ENTIRE COLUMN BELOW 0C...GIVING US A SNOW PROFILE. STILL...MOISTURE APPEARS LIMITED AS THESE TWO FORCING MECHANISMS PASS...THUS WILL TREND TOWARD HIGHER POPS THAN MAVMOS BUT EXPECTING LIGHT AMOUNTS OF PRECIP.
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&& .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 222 AM EDT FRI OCT 31 2014 GFS AND NAM CONTINUE TO SUGGEST ACTIVE WEATHER ONGOING DURING THE EVENING HOURS AS THE STRONG UPPER DISTURBANCE WILL CONTINUE TO BE PASSING THROUGH INDIANA AT 00Z BEFORE EXITING TO THE SOUTHEAST SHORTLY AFTER 06Z. AGAIN...FAVORABLE CONDITIONS WILL EXIST FOR PRECIP DURING THE FIRST FEW HOURS AFTER 00Z AS FORECAST SOUNDINGS REMAIN SATURATED FOR THE FIRST FEW HOURS AFTER 00Z...BEFORE DRYING OUT RAPIDLY AS THE UPPER LOW AND STRONG WINDS ALOFT DEPART QUICKLY. DEEP MOISTURE REMAINS LIMITED WITH NORTHERLY FLOW...BUT STRONG DYNAMICS SHOULD BE ABLE TO PRODUCE SOME LIGHT PRECIP. WARM GROUND SHOULD RESULT IN ANY SNOW MELTING UPON REACHING THE GROUND. THUS WILL TREND AT OR SLIGHTLY ABOVE MAVMOS POPS FOR A FEW HOURS THIS EVENING BEFORE DROPPING POPS OFF QUICKLY BY 06Z AS THE FORCING MECHANISM EXITS. EVENING HOURS WILL BE BLUSTERY...WITH SNOW SHOWERS OR ICE PELLETS POSSIBLE AMID WIND GUSTS OF 20 TO 30 MPH PRODUCING WIND CHILLS TO NEAR 25 DEGREES. FOLKS WHO WILL BE OUTSIDE THIS EVENING WILL GET A TASTE OF EARLY WINTER...AND WILL ISSUE AN SPS TO ADDRESS THIS. AS FOR LOWS...GIVEN THE STRONG COLD AIR ADVECTION...THE FREEZE WARNING REMAINS A GOOD BET...WITH A HARD FREEZE EXPECTED BY 12Z SAT. DRY WEATHER WILL THEN BE EXPECTED ON SATURDAY THROUGH MONDAY AS THE GFS AND NAM SUGGESTS THE STRONG RIDGE OVER THE ROCKIES WILL PUSH EAST AND BUILD ACROSS THE CENTRAL PLAINS AND THEN THE OHIO VALLEY BY MONDAY...WITH THE RIDGE AXIS OVER INDIANA BY 18Z MONDAY. FORECAST SOUNDINGS THROUGH THIS PERIOD SHOW A DRY COLUMN WITH UNREACHABLE CONVECTIVE TEMPS WITH GOOD SUBSIDENCE IN PLACE. THUS WILL TREND TOWARD MOSTLY SUNNY DAYS AND MOSTLY CLEAR NIGHT DURING THIS PERIOD. AS FOR TEMPS WILL TREND BOTH HIGHS AND LOWS COOLER THAN MAVMOS ON SATURDAY AND SATURDAY NIGHT. HOWEVER BY SUNDAY SOUTHERLY FLOW RETURNS AMID SOME WARM AIR ADVECTION ALOFT. WILL STICK CLOSE TO MAVMOS LOWS AND HIGHS SUNDAY THROUGH MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH NEXT THURSDAY/... ISSUED AT 222 AM EDT FRI OCT 31 2014 ENSEMBLES SUGGEST A PROGRESSIVE UPPER PATTERN CAN BE EXPECTED DURING THIS PERIOD. AN UPPER LEVEL RIDGE WILL BE IN THE PROCESS OF MOVING OVER THE FORECAST AREA ON MONDAY...WHILE THE NEXT TROUGH WILL AFFECT THE AREA AROUND THE MIDDLE OF NEXT WEEK. THERE ARE TIMING DIFFERENCES WITH RESPECT TO THE INDIVIDUAL ENSEMBLE MEMBERS AS TO HOW FAST THE NEXT TROUGH WILL MOVE THROUGH...WITH SOME OF THE SLOWER MEMBERS SUGGESTING THE TROUGH WILL NOT PASS UNTIL WEDNESDAY NIGHT. WILL GO WITH POPS FOR RAIN STARTING MONDAY NIGHT AND LINGERING INTO WEDNESDAY NIGHT. AT THIS POINT...IT APPEARS THE BEST PRECIPITATION THREAT WILL BE IN THE TUESDAY TO WEDNESDAY TIME FRAME. && .AVIATION /DISCUSSION FOR THE 311500Z TAF UPDATE/... ISSUED AT 1020 AM EDT FRI OCT 31 2014 LARGE AREA OF RAIN IS MOVING STEADILY EAST ACROSS CENTRAL INDIANA. UPDATED TAFS TO INCLUDE TIMING OF THIS RAIN AND THE MVFR CONDITIONS WITHIN IT. BEHIND THE RAIN CEILINGS WILL VARY BETWEEN VFR AND MVFR FOR A WHILE...BEFORE SETTLING BACK TO MVFR WITH ADDITIONAL SHOWERS THIS AFTERNOON. WINDS ALREADY GUSTING TO NEAR 30KT...AND HIGHER GUSTS POSSIBLE THIS AFTERNOON. PREVIOUS DISCUSSION FOLLOWS... COLD FRONT CURRENTLY PUSHING THROUGH NORTHWEST INDIANA. SHORT TERM MODELS SUGGEST THIS FRONT WILL BE NEAR KLAF BY ISSUANCE TIME...REACHING KBMG AROUND 311500Z. SOME LIGHT RAIN...ALONG WITH THE ARRIVAL OF MVFR CEILINGS AROUND 025 EXPECTED NEAR AND IN THE POST FRONTAL ZONE. SHOULD BE A RATHER SHARP INCREASE IN THE SURFACE WINDS AS WELL WITH FRONTAL PASSAGE...WITH WINDS BECOMING 310-330 DEGREES WITH GUSTS AROUND 25 KTS IN THE WAKE OF THE FRONT. ADDITIONAL RAIN AND SNOW SHOWERS EXPECTED TO DEVELOP BY THE MID TO LATE AFTERNOON HOURS AS THE UPPER LOW MOVES OVERHEAD. AT THIS POINT...APPEARS THE BEST THREAT FOR IFR VISIBILITY RESTRICTIONS THIS AFTERNOON WILL BE OFF TO THE NORTHEAST OF THE TAF SITES WHERE LIFT WILL BE BETTER. AS A RESULT...WILL KEEP VISIBILITY RESTRICTIONS ABOVE IFR FOR NOW. THE CORE OF A 50KT 850MB JET IS PROGGED TO MOVE INTO THE AREA LATER THIS AFTERNOON. GIVEN THE COLD ADVECTION HELPING TO MIX THESE WINDS DOWN...EXPECTING SOME SURFACE GUSTS IN THE 30-35 KT RANGE FROM 320-340 DEGREES BY THE MID TO LATE AFTERNOON HOURS. && .IND WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EDT SATURDAY FOR INZ021-028>031-035>049-051>057-060>065-067>072. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA/MK SHORT TERM...PUMA LONG TERM....JAS AVIATION...JAS/50 VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS

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