201  
FXUS63 KIWX 291022  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
622 AM EDT MON MAY 29 2017  
   
SYNOPSIS
 
 
ISSUED AT 620 AM EDT MON MAY 29 2017  
 
A COLD FRONT WILL MOVE ACROSS THE AREA THIS AFTERNOON BRINGING A  
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS. A WEAK TROUGH ROTATING  
AROUND A STRONG STATIONARY LOW PRESSURE SYSTEM OVER ONTARIO WILL  
BRING A SLIGHT CHANCE OF SHOWERS TO OUR AREA AGAIN TUESDAY.  
TEMPERATURES WILL BE SEASONABLY WARM AGAIN TODAY, BUT,  
A LITTLE COOLER THAN NORMAL TUESDAY AND WEDNESDAY.  
 

 
   
SHORT TERM
 
(TODAY THROUGH TONIGHT)  
ISSUED AT 341 AM EDT MON MAY 29 2017  
 
PARENT UPR LOW OVER SRN ON WILL CONTINUE TO WRAPUP TODAY AS  
SECONDARY DISTURBANCE ROTATING THROUGH THE BASE OF THIS FEATURE  
DRIVES EWD THROUGH MI. TAIL END OF THIS FEATURE WILL ENCOUNTER A  
MARGINALLY UNSTABLE AIRMASS BY AFTN OVER ERN AREAS AND SHOULD  
INITIATE ISOLATED STORMS BY MID AFTN ALONG RESIDUAL THETA-E RIDGE  
ALTHOUGH CAMS GUIDANCE RATHER LACKLUSTER OWING TO SIGNIFICANT  
BOUNDARY LAYER DRYING THAT HAS SPREAD ACROSS THE AREA. OTHERWISE  
STRONG LATE MAY INSOLATION WILL DRIVE CONSIDERABLE HEATING/MIXING  
INTO THIS AFTN WITH FAIRLY GUSTS WSW WINDS.  
 
SKIES WILL CLEAR THIS EVENING BEHIND SECONDARY TROUGH AXIS WITH  
EVEN DRIER AIR SPREADING THROUGH THE AREA MAKING FOR A COOL NIGHT.  
 

 
   
LONG TERM
 
(TUESDAY NIGHT THROUGH SUNDAY)  
ISSUED AT 341 AM EDT MON MAY 29 2017  
 
GENERAL QUIET/SEASONABLY COOL PATTERN UNDER THE INFLUENCE OF UPR LOW  
PERSISTING OVER THE JAMES VALLEY THROUGH THU. THEREAFTER HIGH  
LATITUDE DISTURBANCE OVER NV WILL DROP SOUTH ACROSS HUDSON BAY THEN  
AMPLIFY SE THROUGH NEW ENGLAND NEXT WEEKEND ALLOWING FOR AN ACTIVE  
NW-SE ORIENTED FRONTAL ZONE TO DEVELOP FROM THE NRN PLAINS TO THE  
LOWER OH VALLEY.  
 
BEST INDICATION FOR PRECIP IS ON FRI AS VIGOROUS UPR JET MAX SHIFTS  
THROUGH THE NRN LAKES WITHIN SW PERIPHERY OF UPR LOW DROPPING TOWARD  
NEW ENGLAND. LOW LEVEL WESTERLY JET RESPONSE AND TEMPORARY EWD BUILD  
OF PLAINS THETA-E RIDGE WARRANT HIGH CHANCE POP MENTION ALTHOUGH DID  
BACK AWAY FROM LOW END LIKELY MENTION PER POOR CONSENSUS TIMING ON A  
MORE SPECIFIC FAVORED PERIOD.  
 
THEREAFTER GENERAL HEIGHT SUPPRESSION ALOFT UPSTREAM OF NEW ENGLAND  
UPR LOW SHOULD RESULT IN LOW LEVEL BAROCLINIC ZONE TO SHIFT WELL  
SOUTH THROUGH THE TN VALLEY BY SUN. TORTUROUS BLENDED POP GUIDANCE  
SMATTERS THROUGHOUT THE WEEKEND YET MORE LIKELY SCENARIO IS AREA  
FINALLY DRIES OUT AS EXPANSIVE SFC RIDGE BUILDS IN ACROSS THE LAKES  
AND SORELY NEEDED AFTER A VERY WET MONTH OF MAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 620 AM EDT MON MAY 29 2017  
 
VFR CONDITIONS CONTG ACROSS THE AREA EARLY THIS MORNING. PATCHY ALTO-CU  
IN CYCLONIC FLOW SHOULD GIVE WAY TO HIGH BASED CU THIS AFTN. CDFNT  
OVER WI EXPECTED TO DROP SE ACROSS NRN IN THIS AFTN WITH A FEW SHRA/TS  
DEVELOPING ALONG IT. BETTER CHANCES FOR IMPACTS FROM CONVECTION AGAIN  
TODAY LOOK TO BE AT FWA WHERE FROPA WILL COME LATER IN THE AFTN.  
DEEP MIXING AND UNIDIRECTIONAL FLOW WILL ALLOW FOR WIND GUSTS NEAR  
25KT, LIKELY STRONGER IN/NEAR AND SHRA/TS. WINDS WILL DIMINISH WITH LOSS  
OF HEATING THIS EVE WITH SOME PATCHY ALTO CU LIKELY PERSISTING  
OVERNIGHT.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
MI...NONE.  
OH...NONE.  
LM...NONE.  

 
 

 
 
SYNOPSIS...JT  
SHORT TERM...T  
LONG TERM...T  
AVIATION...JT  
 
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