125  
FXUS63 KIWX 290014  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
814 PM EDT SAT MAR 28 2015  
   
SYNOPSIS
 
 
ISSUED AT 625 PM EDT SAT MAR 28 2015  
 
HIGH PRESSURE WILL BE OVER THE REGION TONIGHT BUT IT WILL BE  
SLIDING SOUTHEASTWARD. A FRONTAL SYSTEM WILL BE MOVING TOWARDS THE  
REGION TONIGHT AND WILL MOVE A WARM FRONT THROUGH TOMORROW WITH A  
COLD FRONT CLOSELY BEHIND. THIS WILL BRING A CHANCE FOR SOME RAIN  
TOMORROW MAINLY IN THE AFTERNOON. LOW TEMPERATURES TONIGHT WILL BE  
IN THE LOWER 20S. HIGH TEMPERATURES TOMORROW WILL RANGE FROM THE  
LOWER 40S IN SOUTHERN MICHIGAN TO AROUND 50 NEAR THE OHIO RIVER.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH SUNDAY)  
ISSUED AT 326 PM EDT SAT MAR 28 2015  
 
QUIET WX EXPECTED THROUGH THE OVERNIGHT AS HIGH PRESSURE CENTERED  
OVER NORTHWEST INDIANA THIS AFTERNOON SHIFTS SOUTHEAST INTO THE  
UPPER OHIO VALLEY TONIGHT. AS RIDGE AXIS SHIFTS EAST OF THE  
AREA...LIGHT RETURN FLOW WILL HELP LIMIT RADIATIONAL TEMPERATURE  
DROP OVERNIGHT. NOT AS COLD AS LAST NIGHT...HOWEVER LOWS IN THE  
LOWER 20S STILL ABOUT TEN DEGREES BELOW NORMAL.  
 
PHASING NRN STREAM VORT MAXES ACROSS NORTHERN TIER WILL DIVE  
SOUTHEAST TOWARDS THE GREAT LAKES ON SUNDAY. ASSOCIATED SFC  
REFLECTION AND COLD FRONT WILL PUSH TOWARD THE AREA THROUGH THE  
MORNING HOURS...WITH PRECIPITATION CHANCES OVERSPREADING THE AREA  
FROM WEST TO EAST LATE MORNING THROUGH THE AFTERNOON HOURS.  
ANTICIPATING ALL RAIN WITH FROPA. WET BULB TEMPS THE LOWEST 3KFT  
LAYER JUST ABOVE THE SFC ARE BELOW FREEZING DURING THE ONSET OF  
PRECIPITATION...HOWEVER SFC TEMPS NEAR 40F AND 5KFT WARM LAYER  
AROUND +5C SHOULD PRECLUDE ANY FROZEN P-TYPES. NO MAJOR CHANGES TO  
POPS SUNDAY OR TEMPS SAT NIGHT AND SUNDAY.  
 

 
   
LONG TERM
 
(SUNDAY NIGHT THROUGH SATURDAY)  
ISSUED AT 326 PM EDT SAT MAR 28 2015  
 
SURE BUT STEADY HGT RISES ACRS THE ERN US XPCD THIS PD AS CONUS FLW  
ALOFT FLATTENS W/CONTD D7 MEANS SHOWING TROUGHING DVLPG THROUGH THE  
WRN US.  
 
HWVR TEMPERMENTAL NRN STREAM FLW ALG THE US/CANADA BORDER QUITE  
FICKLE AS SERIES OF SW TROUGHS GENERALLY AMPLIFY EWD EVERY FEW DAYS.  
FIRST SYS OF NOTE IN THE SHRT TERM SUN FOLLOWED BY ANOTHER  
WEAKER...MSTR STARVED SYS LT MON NIGHT AND GENERALLY DISCOUNTED.  
ANOTHER SYS FOLLOWS AGAIN ON LT WED INTO FRI AS FNTL BNDRY STALLS  
W-E ACRS THE PLAINS/MIDWEST. MODELS MUCH MORE ADAMANT ON LL MSTR  
RTN/ENTRAINMENT DURING THIS TIME PD YET HELD CLOSE TO PRIOR POPS  
WHERE NEEDED. DO NOT XPC A WASHOUT BUT LTR PDS DO LOOK UNSETTLED.  
 
TEMPS BY AND LARGE MODERATING TWD NORMAL TUE ON.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)  
ISSUED AT 735 PM EDT SAT MAR 28 2015  
 
QUIET AVIATION WEATHER TO BEGIN THE FORECAST PERIOD WILL BE  
FOLLOWED BY INCREASING CHANCES OF RAIN TOWARD MIDDAY SUNDAY.  
SURFACE ANTICYCLONE REINFORCED ACROSS SOUTHERN LAKE MICHIGAN WILL  
PROVIDE AN HOUR OR TWO OF ONSHORE FLOW/NORTHWEST WINDS AT KSBN  
BEFORE WINDS BECOME LIGHT AND VARIABLE. SFC ANTICYCLONE WILL SHIFT  
SOUTHEAST TONIGHT ALLOWING SOUTH WINDS OF 5 TO 10 KNOTS TO  
DEVELOP OVERNIGHT...AND THEN 10 TO 15 KNOTS TOWARD DAYBREAK. THE  
NEXT SIGNIFICANT SHORT WAVE ACROSS MONTANA THIS EVENING WILL REACH  
THE SOUTHERN GREAT LAKES BY SUNDAY EVENING. STRONG LOW LEVEL  
THEATE ADVECTION IN ADVANCE OF THIS WAVE WILL ADVECT INTO NORTHERN  
INDIANA SUNDAY AFTERNOON WITH A GOOD CHANCE OF RAIN AFTER 17Z.  
SOME LOW END POTENTIAL OF A VERY BRIEF PERIOD OF SLEET AT ONSET OF  
PRECIP...BUT STILL EXPECTING PRIMARILY RAIN. SFC WINDS TO BE  
ENHANCED BY STRONG SFC PRESSURE FALLS PROGRESSING ACROSS THE SOUTHERN  
GREAT LAKES SUNDAY...ALLOWING FOR SOUTH WIND GUSTS OF AROUND 30  
KNOTS. SOME LOWER END MVFR CONDITIONS ARE ALSO POSSIBLE TOWARD THE  
END OF THE PERIOD.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
MI...NONE.  
OH...NONE.  
LM...GALE WARNING FROM 11 AM TO 5 PM EDT SUNDAY FOR LMZ043-046.  
 

 
 

 
 
SYNOPSIS...LOTHAMER  
SHORT TERM...NG  
LONG TERM...T  
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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