Area Forecast Discussion
Issued by NWS Northern Indiana

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000 FXUS63 KIWX 021102 AFDIWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 702 AM EDT TUE SEP 2 2014 .SYNOPSIS... ISSUED AT 700 AM EDT TUE SEP 2 2014 DRIER AND COOLER AIR WILL INFILTRATE THE REGION AS A COLD FRONT PUSHES SOUTH INTO THE OHIO VALLEY TODAY. UNTIL THEN SOME RAINFALL ASSOCIATED WITH A LARGE CONVECTIVE COMPLEX WILL MOVE THROUGH THE REGION...PRIMARIY SOUTH OF ROUTE 24 THIS MORNING. AS HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA...LOOK FOR CLEARING SKIES THIS AFTERNOON...WITH HIGHS NEAR 80 DEGREES...EXCEPT COOLER NEAR LAKE MICHIGAN. LOWS TONIGHT WILL DIP INTO THE MIDDLE TO UPPER 50S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 405 AM EDT TUE SEP 2 2014 WOEFULLY DISHEARTENED BY POORLY MISHANDLED FINER RES MODEL OUTPUT WITH RESPECT TO SPASTIC PRIMARY/DERIVED FIELDS THIS AM. NAM12 TOO MOIST IN BOUNDARY LAYER AND LATER AFTERNOON INSTABILITY AND HRRR3KM EGREGIOUSLY OVERLY ASSERTS MINOR MID LEVEL CONVERGENCE WITH HEAVY AMOUNTS IN A STRIPE ACROSS NWRN/NRN CWA THIS AM. FOLLOWING LESS NOISY/CONCEPTUALLY FAVORED SREF/GFS THROUGH NEAR TERM. ZONE OF MARKED 7-5H QG FGEN OVER WCNTL MI INTO NERN IL TO RACE ENEWD INTO MI THUMB/SWRN ONT BY ABOUT 15 UTC. ANTICIPATE LITTLE MORE THAN LIGHT SHRA GIVEN LEADING EDGE 850-700MB MOISTURE FLUX DIVERGENCE ASSOCIATED WITH DRYING SUB ALTOCU DECK LAYER. MEANWHILE TO SOUTH...CONVECTIVE COMPLEX ASSOCIATED WITH WELL VEERED 925-8H JETLET NEAR SWRN IN/NCNTL KY ON ORDER OF 45-50KTS. WELL VEERED JET FOCUS THROUGH REMAINDER OF AM HOURS TO KEEP HEAVY RAFL WELL SOUTH OF CWA...WITH NORTHERN EDGE /PRIMARILY STRATIFORM QUALITY RAINSHIELD PASSING THROUGH SRN/SERN CWA WITH STRONG POP GRADIENT. GIVEN ML CAPE 250 J/KG ISOPLETH TO REMAIN ALONG/SOUTH OF INTERSTATE 70 WAS TEMPTED TO REMOVE TSRA ALTOGETHER...HOWEVER MAINTAINED A TOKEN ISOLD/SLIGHT CHANCE MENTION FAR S/SERN CWA THROUGH 12 UTC PRIMARILY FOR PSBL ANVIL/PERIPHERAL MCS STRIKE. OTHERWISE...GRADUAL INFILTRATION OF DRIER AIR AND PROGRESSION OF LONGWAVE TROF LEAVES LITTLE IMPETUS FOR AFTERNOON CONVECTIVE DEVELOPMENT AND SIDED DRY/BECOMING MOSTLY SUNNY. AMPLE LONGWAVE RADIATIONAL COOLING CONDITIONS BY SUNSET AS CENTRAL PLAINS SURFACE RIDGING EDGES EASTWARD INTO SOUTHWEST GREAT LAKES/MID MS VLY. GIVEN CLEAR/MCLEAR SKIES AND 925 MB THERMAL TROF POSITIONING FROM LAKE HURON SW INTO EASTERN THIRD CWA BY DAYBREAK...HAVE FAVORED ONGOING COOL TEMPS/CLOSER TO MAV GUID. WITH STRONG SURFACE BASED INVERSION ANTICIPATE POSSIBLE FG ISSUE...UNCERTAINTY OF COVERAGE...THOUGH WITH WETTING ACROSS SOUTHERN CWA THIS AM...HAVE OPTED TO INTRODUCE AS AREAS OF FOG FOR NOW...ALLOWING LATER SHIFTS TO EVALUATE PROBABILITY OF DENSE NATURE. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 405 AM EDT TUE SEP 2 2014 WEAK SFC HIGH PRESSURE CENTER WILL WORK SLOWLY ESE TOWARD THE EASTERN OH VALLEY ON WEDNESDAY PROVIDING THE AREA WITH DRY/FAIR WX AND HIGHS INTO THE LOW-MID 80S GIVEN AMPLE INSOLATION AND 850 MB TEMPS NEAR 15C. NORTHERN STREAM WILL REMAIN ACTIVE/PROGRESSIVE THROUGH THE REMAINDER OF THE PERIOD AS NEXT MID LEVEL TROUGH AXIS (SOON TO DROP INTO THE PAC NW) PROPAGATES ENE ALONG THE US/CANADA BORDER LATE THIS WEEK. THETA-E/WARM FRONT SURGE IN RESPONSE TO ATTENDANT CENTRAL PLAINS TO UPPER MIDWEST SFC TROUGH DEVELOPMENT BRINGS CONVECTIVE CHANCES INTO QUESTION BY LATER WEDNESDAY NIGHT/THURSDAY MORNING. WITH THAT SAID CONTINUED WITH INHERITED DRY/10 POP FCST IN LIGHT OF CONSISTENT ECMWF DRY SIGNAL WITH MORE PRONOUNCED MOISTURE CONVERGENCE SETTING UP NORTHWEST OF THE FA ON NOSE OF LLJ. THURSDAY AFTN/NIGHT SHOULD FEATURE MAINLY DRY/HOT/HUMID CONDITIONS WITH CAPPED WARM SECTOR BECOMING FIRMLY ESTABLISHED. DEPENDING ON CLOUD/CONVECTIVE TRENDS TEMPS MAY MAKE A RUN AT 90F THURSDAY IN THE WEST AS SW FLOW DEEPENS AND 850 MB TEMPS INCREASE TO 20-21C. MODELS REMAIN IN GOOD AGREEMENT IN SAGGING A TRAILING/WEAKENING COLD FRONT INTO A MOIST/UNSTABLE ENVIRONMENT FRIDAY-FRIDAY EVE. CONTINUED TO UNDERCUT LIKELY CONSENSUS BLEND POPS FOR STORMS GIVEN WEAK MID LEVEL FORCING/LAPSE RATES IN PART TO NORTHERLY TRACK OF MAIN PV ANOMALY THRU ONTARIO. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IF CONVECTION FIRES GIVEN HIGH MOISTURE CONTENT/POOLING...WITH NOT MUCH OF A SEVERE RISK GIVEN POST- FRONTAL LAG OF STRONGER MID LVL FLOW. OTHERWISE...THIS WEEKEND INTO EARLY NEXT WEEK WILL BE CHARACTERIZED BY DRY (EXCEPT FOR VERY LOW SHOWER CHC SOUTHEAST SATURDAY IF SLOWER FRONTAL PASSAGE COMES TO FRUITION) AND MUCH COOLER WEATHER IN RESPONSE TO BUILDING HIGH PRESSURE IN WAKE OF COLD FRONT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 649 AM EDT TUE SEP 2 2014 RAIN SHIELD TO CONTINUE EASTWARD ADVANCE THROUGH NWRN OHIO WITH LITTLE MORE THAN LIGHT RAIN WITH VFR MET CONDITIONS FOR KFWA. A FEW SHRA NIVOF KSBN...IMMEDIATELY ALONG FRONTAL BOUNDARY/COLLOCATED MID LEVEL CONVERGENCE AXIS. AGAIN DO NOT ANTICIPATE MUCH IF ANY AVIATION RELATED CONCERN APART FROM WET RY/TEMPO MVFR CIGS...BUT MAINTAIN OPTIMISM ABOVE FUELING/ALTERNATE CRITERIA. FOCUS THEN SHIFTS TO POTENTIAL BR/FG DEVELOPMENT TOWARD DAYBREAK WEDNESDAY. WETTED GROUND/HIGHER XOVER TEMP AT KFWA SUGGESTS GREATER LIKLIHOOD FOR DETERIORATING CONDITONS THAN ACROSS NWRN IN/VCNTY KSBN. ADDRESS POTENTIAL FOR IFR VSBSY IN TEMPO PERIOD FOR OUTLOOK/PLANNING PURPOSES AT KFWA. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MURPHY SHORT TERM...MURPHY LONG TERM...STEINWEDEL AVIATION...MURPHY VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

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