505 FXUS63 KIND 161033 AFDIND AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 533 AM EST TUE DEC 16 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 251 AM EST TUE DEC 16 2014 A LOW PRESSURE SYSTEM WILL EXIT THE AREA TODAY. IN THE WAKE OF THIS SYSTEM...HIGH PRESSURE IS EXPECTED INTO THE LATER PORTIONS OF THE WEEK. A LOW PRESSURE SYSTEM MAY AFFECT THE AREA OVER THE WEEKEND. && .NEAR TERM /TODAY/... ISSUED AT 251 AM EST TUE DEC 16 2014 AREA OF RAIN CURRENTLY MOVING THROUGH THE LOCAL AREA IN ASSOCIATION WITH A SURFACE LOW AND OCCLUSION. APPEARS MOST OF THIS WILL BE IN THE PROCESS OF EXITING THE AREA BY SUNRISE. SHORT TERM MODELS SUGGEST THE UPPER TROUGH WILL BE PASSING THROUGH LATER THIS MORNING. AS A RESULT...WILL KEEP SOME POPS GOING FOR LIGHT RAIN...ESPECIALLY DURING THE MORNING HOURS. AS THE UPPER TROUGH PULLS AWAY THIS AFTERNOON...THE PRECIPITATION THREAT SHOULD DIMINISH AS WELL. GIVEN THE COLD ADVECTION IN THE WAKE OF THE LOW...APPEARS HIGHS TODAY WILL BE REACHED THIS MORNING...WITH TEMPERATURES NEARLY STEADY OR SLOWLY FALLING THIS AFTERNOON. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 251 AM EST TUE DEC 16 2014 FAIRLY QUIET WEATHER EXPECTED DURING THIS PERIOD AS ZONAL UPPER FLOW UNDERCUTS A BLOCK OVER SOUTHERN CANADA. WILL KEEP SOME SMALL CHANCE POPS GOING FOR LIGHT RAIN OR SNOW THIS EVENING OVER THE EASTERN ZONES TO COVER ANY LINGERING PRECIPITATION POTENTIAL IN THE WAKE OF TODAY/S UPPER TROUGH...BUT THIS DOESN/T LOOK LIKE A BIG DEAL. OTHERWISE...WILL GO WITH A DRY FORECAST FOR THE REST OF THE PERIOD AS SURFACE HIGH PRESSURE NOSES INTO THE AREA FROM THE NORTHERN PLAINS. A SUBSIDENCE INVERSION DEVELOPS THIS EVENING WHICH LINGERS INTO THURSDAY OR THURSDAY NIGHT. AS A RESULT...THINK THERE WILL BE QUITE A BIT OF CLOUD COVER AROUND OVER THE NEXT FEW DAYS. MODELS SUGGEST THERE MAY BE SOME LIFT DEVELOPING OVER THE SURFACE HIGH PRESSURE RIDGE BY THURSDAY. OPERATIONAL AND ENSEMBLE DATA SUGGEST LITTLE THREAT OF PRECIPITATION AT THIS TIME...BUT WILL MONITOR THE TRENDS. DUE TO EXPECTED CLOUD COVER OVER THE NEXT FEW DAYS...WILL TEMPER THE DIURNAL RANGE OF THE GFS MOS TEMPERATURE GUIDANCE BY ABOUT A CATEGORY PER PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 332 AM EST TUE DEC 16 2014 MAIN FOCUS FOR THE EXTENDED WILL BE SNOW POTENTIAL ALONG WITH TIMING AND TEMPERATURES. DETERMINISTIC MODELS ARE NOW ATTEMPTING TO CONVERGE ON A SIMILAR SOLUTION...ALTHOUGH THE ECMWF LOOKS A BIT SLOW BRINGING QPF ACROSS THE FORECAST AREA. THE 00Z GEM AND GFS BOTH HAVE QPF ACROSS OUR SOUTHERN COUNTIES FRIDAY NIGHT AS ENERGY LIFTS NORTHEAST FROM THE LOWER MISSISSIPPI VALLEY AHEAD OF AN APPROACHING UPPER TROUGH OVER THE SOUTHERN PLAINS. STILL...THIS MARKS A CHANGE AS PREVIOUS MODEL RUNS SUGGESTING THE PRECIPITATION WOULD BE FURTHER NORTH AND ENVELOP OUR ENTIRE FORECAST AREA. FURTHER SOUTHERLY TRACK SUGGESTS AREAS NEAR AND NORTH OF INTERSTATE 70 SHOULD BE DRY FRIDAY NIGHT. AS THE UPPER TROUGH PASSES THROUGH ON SATURDAY...PRECIPITATION SHOULD SPREAD FAR ENOUGH NORTH TO KEEP CHANCE POPS IN ALL OF CENTRAL INDIANA. FINALLY...SYSTEM TO DAMPEN SATURDAY NIGHT AS IT MOVES EAST AND BECOMES ABSORBED IN NORTHERN STREAM LOW OVER THE UPPER MIDWEST AND ONTARIO. THE REST OF THE EXTENDED LOOKS TO BE DRY AS SURFACE HIGH PRESSURE SETTLES SOUTHEAST OVER THE GREAT LAKES AND OHIO VALLEY. PRECIPITATION TYPE SHOULD BE MOSTLY SNOW BASED ON MODEL SOUNDINGS AND CRITICAL THICKNESSES...ALTHOUGH WOULD NOT RULE OUT SOME SLEET OR FREEZING RAIN AT THE ONSET FRIDAY NIGHT...FAR SOUTH AS WARM LAYER ALOFT MOVES INTO THAT AREA. WILL KEEP IT JUST SNOW FOR NOW...HOWEVER AND TAKE ANOTHER LOOK AT IT AFTER SUBSEQUENT MODEL RUNS. NOT EXPECTING MUCH ACCUMULATION WITH THIS SYSTEM BASED ON THE CURRENT TRACK CONSENSUS. EVEN IN THE SOUTHERN SECTIONS...IT DOES NOT LOOK LIKE MORE THAN AN INCH AT THIS POINT. WITH THE SYSTEM TRENDING FURTHER SOUTH PER THE MORE CONSISTENT ECMWF AND ITS ENSEMBLE MEANS...PREFER THE COOLER GFS ENSEMBLE MEMBERS ALONG WITH THE ECMWF ENSEMBLE MEANS WHICH MATCH NICELY WITH THE 00Z REGIONAL BLEND. && .AVIATION /DISCUSSION FOR THE 161200Z TAF ISSUANCE/... ISSUED AT 533 AM EST TUE DEC 16 2014 IFR CEILINGS SHOULD IMPROVE TO MVFR NEAR ISSUANCE TIME PER LATEST UPSTREAM OB TRENDS. COULD ALSO SEE A FEW LIGHT SHOWERS AROUND THROUGH 20Z OR SO TODAY BEFORE THE LOW PULLS AWAY OVER SOUTHERN ONTARIO. WINDS WILL BE SOUTHWEST AND THEN WEST AND INREASE TO NEAR 15 KNOTS WITH GUSTS TO 20 KNOTS OR MORE AFTER 14Z. WINDS WILL EASE UP A BIT AFTER 00Z AS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JAS NEAR TERM...JAS SHORT TERM...JAS LONG TERM...MK AVIATION...MK 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