Area Forecast Discussion
Issued by NWS Northern Indiana

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000 FXUS63 KIWX 010100 AFDIWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 900 PM EDT THU JUL 31 2014 .SYNOPSIS... ISSUED AT 335 PM EDT THU JUL 31 2014 OTHER THAN A OUTSIDE CHANCE FOR A SHOWER INTO MID EVENING...DRY AND PLEASANT CONDITIONS WILL PREVAIL ACROSS THE REGION. LOWS TONIGHT WILL DROP INTO THE UPPER 50S TO AROUND 60. A WEAK SYSTEM WILL APPROACH THE AREA ON FRIDAY...BRINGING A SLIGHTLY BETTER CHANCE FOR AFTERNOON SHOWERS AND THUNDERSTORMS. HIGHS WILL CLIMB TO AROUND 80. && .UPDATE... ISSUED AT 830 PM EDT THU JUL 31 2014 THE COMBINATION OF A WEAK LOW LEVEL CONVERGENCE AXIS ENHANCED BY SYNOPTICALLY MODIFIED LAKE BREEZE AND A WEAK UPPER LEVEL DISTURBANCE AIDED IN ISOLATED/SCATTERED SHOWERS AND THUNDERSTORM DEVELOPMENT EARLIER THIS EVENING. THIS SHORT WAVE APPEARS TO BE DEPARTING TO THE EAST...BUT ISOLATED SHOWERS MAY PERSIST OVER NEXT FEW HOURS ALONG THIS OUTFLOW REINFORCED CONVERGENCE BOUNDARY. HAVE MADE SOME JUST MINOR TWEAKS TO POPS TO ACCOUNT FOR DIMINISHING SHOWER COVERAGE ALONG THIS BOUNDARY THIS EVENING. EASTWARD EXTENSION OF UPPER LEVEL VORT MAX DROPPING OUT OF EASTERN SOUTH DAKOTA/SOUTHERN MINNESOTA SHOULD ALSO BEGIN TO NOSE INTO WESTERN GREAT LAKES REGION OVERNIGHT...WHICH MAY ALLOW FOR ISOLATED SHOWER REDEVELOPMENT...PRIMARILY NORTHWEST HALF OF THE AREA. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 353 PM EDT THU JUL 31 2014 DEVELOPMENT OF CU THUS FAR HAS BEEN RELATIVELY LIMITED TO AN AREA OF SLIGHTLY BETTER MOISTURE CONCENTRATION AND EDGE OF LAKE SHADOW. WEAK AREA OF CONVERGENCE NOTED ON SFC OBS AT 19Z BETWEEN THE LAKE SHADOW AREA (ROUGHLY MICHIGAN CITY TO CASSOPOLIS) AND MINOR WIND SHIFT ( MONTICELLO TO WARSAW TO COLDWATER). FEW SHOWERS AND STORMS WILL BE POSSIBLE THROUGH EARLY EVENING IN THIS AREA WITH AROUND 1000 J/KG OF SURFACE BASED CAPE AVAILABLE BUT SHOULD POSE NO ISSUE WITH NO SHEAR TO ALLOW FOR ORGANIZATION. WOULDN`T BE ENTIRELY SURPRISED TO SEE COMPLETELY DRY CONDITIONS AS WAS HINTED AT BY 00Z 4 KM SPC WRF. A PLEASANT EVENING WILL BE ON TAP WITH LOWS DROPPING INTO THE UPPER 50S TO AROUND 60. ALTHOUGH PESKY UPPER LEVEL LOW IN VICINITY OF JAMES BAY WILL BE SLOWLY MOVING AWAY...THE FIRST OF 2 WAVES WILL ROUND THE BASE OF THE TROUGH DURING THE DAY FRIDAY. CURRENT WIDELY SCATTERED ACTIVITY IN WISCONSIN COULD DRIFT IN TOWARDS MORNING AS THE EDGE OF THE WAVE APPROACHES. SLGT CHC HELD ONTO LATER TONIGHT BUT SE EXTENT LIMITED. WHILE SHEAR PROFILES WILL BE UNIMPRESSIVE...MOISTURE WILL BE SUFFICIENT ALONG WITH A QUICK SHOT OF SLIGHTLY COOLER MID LEVEL AIR TO ALLOW FOR A SOMEWHAT BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS FRIDAY AFTERNOON. SPC DOES HAVE MUCH OF THE CWA IN A 5 PERCENT PROB FOR PULSE TYPE STORMS FRI AFTERNOON/EVE. NOT OVERLY EXCITED WITH SEVERE CHANCES GIVEN ENVIRONMENT IS GENERALLY THE SAME AS PAST SEVERAL DAYS. HOWEVER...WITH A BIT BETTER UPPER SUPPORT CAN`T RULE OUT A STRONGER STORM PRODUCING A WET MICROBURST OR MARGINAL SEVERE HAIL. MAY FRESHEN UP HWO A BIT TO GIVE PASSING MENTION OF MARGINAL THREAT. TEMPS WILL CLIMB TO AROUND 80...ALTHOUGH INCREASE IN CLOUDS WITH THE SYSTEM MAY TEMPER THAT A BIT. && .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 353 PM EDT THU JUL 31 2014 DEEP STNRY LOW NEAR JAMES BAY EXPECTED TO BE LIFTING OUT TO THE NE BY FRI NIGHT AND WKNG... THOUGH TROF HANGING BACK ACROSS OUR AREA FCST TO SHARPEN UP A BIT EARLY IN THE WEEKEND AS A COUPLE OF VORT MAXES ROTATE THROUGH THE BASE ACROSS IL/IN. DIURNAL HEATING SHOULD LEAD TO WK-MOD INSTABILITY WHICH MAY ALLOW SCT AFTN TSTMS TO DEVELOP. 12Z GFS HAS TRENDED A LITTLE FASTER TO MOVE UPR TROF EAST OF THE AREA SUNDAY... IN BETTER AGREEMENT WITH LATEST/RECENT ECMWF... SUGGESTING DRY CONDITIONS ACROSS OUR CWA ON SUNDAY. SHRTWV MOVG OVER TOP OF WRN NORTH AMERICA RIDGE THIS AFTN IS EXPECTED TO DROP SE TO QUEBEC BY MONDAY WITH A TRAILING BACKDOOR CDFNT MOVG INTO OR STALLING OUT JUST NORTH OF OUR CWA. WK FORCING ALONG THE FRONT SHOULD ALLOW FOR DRY CONDITIONS TO PERSIST IN OUR AREA THROUGH MONDAY. BY TUE THERE MAY BE SUFFICIENT MOISTURE POOLING COMBINED WITH A WK SHRTWV MOVG ESE ACROSS LM TO PRODUCE A FEW SHOWERS/TSTMS. CONVECTIVE CHANCES GRDLY INCREASE WED-THU AS FLOW AMPLIFIES ONCE AGAIN WITH BUILDING UPR RIDGE IN WRN U.S. AND DEEPENING TROF MOVG INTO GRTLKS WITH MOISTURE/INSTABILITY FOCUSED ALONG STALLED SFC BOUNDARY ACROSS OUR AREA. TEMPS SHOULD BE NEAR NORMAL THROUGH THIS PERIOD. FAIRLY DRY AIRMASS AND LIGHT FLOW SHOULD RESULT IN RATHER LARGE DIURNAL SWINGS THROUGH THE WEEKEND WITH WARMER NIGHTS NEXT WEEK AS LOW LEVEL MOISTURE INCREASES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 830 PM EDT THU JUL 31 2014 ISOLATED SHOWERS AND THUNDERSTORMS ALONG OUTFLOW REINFORCED CONVERGENCE BOUNDARY...SHOULD GENERALLY REMAIN SOUTH OF KSBN AND NORTH OF KFWA OVER THE NEXT FEW HOURS BEFORE DISSIPATING. ANOTHER WEAK UPSTREAM SHORT WAVE SHOULD BEGIN TO TRACK INTO THE WESTERN GREAT LAKES OVERNIGHT...THAT MAY ALLOW FOR ISOLATED SHOWER REDEVELOPMENT ACROSS NORTHWEST/NORTH CENTRAL INDIANA OVERNIGHT. WILL MAINTAIN A DRY FORECAST THROUGH THE OVERNIGHT WITH WANING INSTABILITY AND OVERALL WEAK NATURE OF MID/UPPER LEVEL FORCING. UPPER FORCING TO BECOME A BIT MORE PRONOUNCED ON FRIDAY AS UPSTREAM VORT MAX VERY SLOWLY MEANDERS ACROSS THE SOUTHERN GREAT LAKES DURING PEAK HEATING. SCATTERED SHOWERS/THUNDERSTORMS APPEAR TO BE A GOOD POSSIBILITY ACROSS NORTHERN INDIANA FRIDAY AFTERNOON...BUT AT THIS FORECAST DISTANCE WITH LOWER CONFIDENCE IN OCCURRENCE AT SPECIFIC TERMINALS...WILL KEEP FORECAST DRY FRIDAY AT THIS TIME. GENERALLY VFR CONDITIONS ARE EXPECTED...ALTHOUGH SOME PATCHY FOG IS POSSIBLE LATE TONIGHT AND CANNOT COMPLETELY RULE OUT SHORT LIVED MVFR VSBYS EARLY FRIDAY MORNING...BUT ONCE AGAIN CONFIDENCE IS TOO LOW FOR INCLUSION AT THIS TIME. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...MARSILI SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...JT AVIATION...MARSILI 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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