632  
FXUS63 KAPX 040749  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
349 AM EDT WED MAY 4 2016  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 349 AM EDT WED MAY 4 2016  
 
COLD FRONT HAS REACHED NW LWR MICHIGAN EARLY THIS MORNING...  
PRODUCING SCT/NMRS RAIN SHOWERS ALONG AND EITHER SIDE OF THIS  
BOUNDARY. THUNDERSTORMS ARE DIMINISHING OVER NRN ILLINOIS ALONG THE  
SW TIP OF THE COLD FRONT...FUELED BY WEAK INSTABILITY (MUCAPES  
AROUND 500 J/KG) AND MODEST 850 MB THETA E RIDGING LAST NIGHT. LACK  
OF INSTABILITY PRECLUDED THE DEVELOPMENT OF ANY THUNDER ACROSS OUR  
CWA LAST NIGHT OR EARLY THIS MORNING. IN FACT...AREAL COVERAGE AND  
INTENSITY OF PRECIP HAVE BEEN RATHER UNIMPRESSIVE SO FAR...BUT DOES  
APPEAR TO BE TRYING TO FILL IN AS LOW LEVEL MOISTURE FINALLY BEGINS  
TO INCREASE IN EARNEST. SUSPECT THAT THE STRONGER/MORE WIDESPREAD  
CONVECTION TO OUR SW DURING THE NIGHT MAY HAVE INITIALLY STOLEN SOME  
OF THE AVAILABLE MOISTURE NEEDED FOR MORE WIDESPREAD PRECIP  
PRODUCTION FURTHER TO THE NE ALONG THE FRONT. BUT THIS EFFECT IS  
DIMINISHING AS THE CONVECTION TO OUR SW SLOWLY WANES AS WE APPROACH  
PEAK DIURNAL COOLING.  
 
LATEST RAP13 AND NAM13 HAVE BOTH FURTHER STALLED THE EASTWARD  
PROGRESS OF THIS SYSTEM OVER THE NEXT 24 HRS...KEEPING CHANCES OF  
PRECIP IN OUR FORECAST THRU TONIGHT...ESPECIALLY FOR OUR ERN CWA.  
THIS SOLUTION SEEMS REASONABLE GIVEN THE EXPECTATION THAT THE SYSTEM  
BECOMES VERTICALLY-STACKED AS IT MOVES THRU THE WRN GREAT LAKES.  
ALSO...DEFORMATION AXIS DOES SET UP RIGHT OVER THE ERN HALF OF OUR  
CWA THIS AFTERNOON AND TONIGHT AS THE 500 MB LOW CLOSES OFF SOUTH OF  
MICHIGAN. SHOULD BE PLENTY OF LINGERING MOISTURE IN THE WAKE OF THE  
FRONT TO EXTENT PRECIP PRODUCTION THRU TONIGHT. HAVE THEREFORE MADE  
OVERALL UPWARD ADJUSTMENTS TO POPS AND QPF TODAY AND TONIGHT...  
ESPECIALLY FOR THE ERN HALF OF OUR CWA. UNDER THICK CLOUDS AND  
SCT/NMRS SHOWERS...TEMPS WILL ONLY WARM INTO THE UPPER 40S AND LOWER  
50S THIS AFTERNOON...WITH BRISK NORTHERLY WINDS. LOW TEMPS TONIGHT  
WILL COOL BACK INTO THE UPPER 30S TO LOWER 40S.  
   
LONG TERM
 
(THURSDAY THROUGH TUESDAY)  
ISSUED AT 349 AM EDT WED MAY 4 2016  
   
..WARMING TREND TO END THE WEEK/RAIN BY SATURDAY
 
 
HIGH IMPACT WEATHER POTENTIAL: MINIMAL.  
 
PATTERN SYNOPSIS/FORECAST: AMPLIFIED RIDGE WEST/TROUGH EAST PATTERN  
DOMINATES NORTH AMERICA EARLY THIS MORNING...WITH SHORT WAVE  
TROUGHING DIGGING SOUTHEAST ACROSS THE GREAT LAKES AND INTO THE MEAN  
TROUGH POSITION. A COMPACT "BOWLING BALL" OF ENERGY SPINNING ITS  
WAY ALONG THE WEST SIDE OF BAFFIN ISLAND...SHOULD REMAIN NORTH OF  
MICHIGAN AS A RIDGE AXIS/DEFORMATION ZONE DEVELOPING ACROSS THE  
GREAT LAKES LATER THURSDAY INTO FRIDAY KEEPS THIS FEATURE AT BAY.  
OVERALL PATTERN EXPECTED TO BECOME MORE BLOCKY FOR THE END OF THE  
WEEK WITH A LARGE CLOSED LOW OVER THE SOUTHWESTERN STATES AND A  
SIMILAR FEATURE ALONG THE EAST COAST.  
 
SURFACE COLD FRONT DROPPING THROUGH THE UPPER LAKES EARLY THIS  
MORNING...WITH HIGH PRESSURE OVER THE CANADIAN PRAIRIES. THIS  
RIDGING IS EXPECTED TO BUILD SOUTHEAST INTO MICHIGAN FOR THURSDAY  
INTO FRIDAY. RIDGE PORTION OF THE BLOCK EXPECTED TO BE FLATTENED BY  
SHORT WAVE TROUGHING COMING OVER THE TOP ACROSS THE PRAIRIE  
PROVINCES FRIDAY. THIS FEATURE WILL PUSH A COLD FRONT INTO THE  
UPPER LAKES BY SATURDAY MORNING.  
 
PRIMARY FORECAST CONCERNS: PRECIPITATION CHANCES FRIDAY NIGHT.  
 
THURSDAY...WILL PROBABLY SEE SOME LINGERING CLOUDINESS AROUND  
THURSDAY MORNING AS HIGH PRESSURE BUILDS IN FROM THE NORTH...MIXING  
INTO SOME CUMULUS AS THE DAY PROGRESSES. EXPECTED TO BE A FAIR BIT  
WARMER THURSDAY AFTERNOON THAN THIS AFTERNOON...WITH HIGHS WARMING  
BACK INTO THE UPPER 50S AND 60S WITH SOME LAKE BREEZE ACTIVITY.  
MOSTLY CLEAR AND COOL FOR THURSDAY NIGHT...LOWS EXPECTED TO DROP  
INTO THE 30S MOST AREAS.  
 
FRIDAY...BLOCKING PATTERN WILL BE FIRMLY ESTABLISHED WITH A WEAK  
UPPER LEVEL RIDGE AXIS/DEFORMATION ZONE LYING WEST-EAST ACROSS THE  
FORECAST AREA. SHOULD BE ANOTHER NICE DAY WITH TEMPERATURES GETTING  
BACK INTO THE 70S AT LEAST ACROSS NORTHERN LOWER. SHORT WAVE TROUGH  
COMING OVER THE TOP OF THE WESTERN RIDGE AND AN ASSOCIATED COLD  
FRONT EXPECTED TO APPROACH FROM THE NORTHWEST FRIDAY NIGHT. LOW  
LEVEL THETA-E RIDGE ALONG/AHEAD OF THE FRONT WILL PROVIDE AN  
OPPORTUNITY FOR SHOWERS AFTER MIDNIGHT AND PERHAPS SOME  
ELEVATED THUNDERSTORMS AS WELL.  
 
EXTENDED FORECAST (SATURDAY THROUGH TUESDAY)...BLOCKY PATTERN  
MENTIONED ABOVE FORECAST TO EVOLVE A BIT THIS WEEKEND...AS RIDGE  
AXIS/DEFORMATION ZONE GETS SHOVED SOUTHEAST ON SATURDAY AS HEIGHT  
FALLS OVERSPREAD THE GREAT LAKES FROM THE NORTHWEST. THIS SHOULD  
RESULT IN ANOTHER COOL SHOT TO END THE WEEKEND...WITH SOME  
MODERATION IN TEMPERATURES PROBABLY FOR EARLY NEXT WEEK.  
 
SHOWER/THUNDERSTORM CHANCES WILL CONTINUE SATURDAY AS COLD FRONT  
CONTINUES ITS PASSAGE ACROSS LOWER MICHIGAN...SHOULD DRY OUT FOR  
SUNDAY WITH ANOTHER CHANCE OF RAIN BY TUESDAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1147 PM EDT TUE MAY 3 2016  
 
LOW PRESSURE SYSTEM IS CURRENTLY DROPPING DOWN THROUGH THE NRN  
GREAT LAKES WITH A SHARP COLD FRONT THAT STRETCHES FROM EASTERN UPPER  
MICHIGAN DOWN THROUGH SOUTHERN WISCONSIN. THIS SYSTEM WILL DIG  
INTO THE GREAT LAKES REGION OVERNIGHT...WHILE SLOWING/STALLING A  
BIT HEADING INTO WEDNESDAY. BAND OF SHOWERS ALONG THE FRONT WILL  
CONTINUE TO SLIDE THROUGH NRN LOWER MICHIGAN TONIGHT INTO  
WEDNESDAY WHILE GRADUALLY DIMINISHING THROUGH THE DAY WEDNESDAY.  
 
CONDITIONS REMAIN VFR AT THE TERMINAL SITES AT THIS JUNCTURE. BUT  
AFTER FROPA AND SUBSTANTIALLY COOLER AIR SLIPS INTO THE REGION...STILL  
BELIEVE CIGS WILL LOWER TO MVFR AND POSSIBLE IFR LATER OVERNIGHT/  
EARLY WEDNESDAY.  
 
ON WEDNESDAY...SHOWERS WILL HANG AROUND ACROSS NE LOWER MICHIGAN  
FOR A GOOD PART OF THE DAY BEFORE ENDING. BUT CIGS WILL GRADUALLY  
IMPROVE TO HIGH MVFR...POSSIBLE VFR BY LATE AFTERNOON INTO THE  
EVENING HOURS...ESPECIALLY AT TVC/PLN/MBL.  
 

 
   
MARINE
 
 
ISSUED AT 349 AM EDT WED MAY 4 2016  
 
BRISK NORTHERLY FLOW IN THE WAKE OF THE COLD FRONT WILL PRODUCE SCA  
CONDITIONS FOR OUR NEARSHORE AREAS OF NRN LAKE MICHIGAN TODAY AND  
TONIGHT...AS WELL AS THE WHITEFISH BAY AREA THRU EARLY AFTERNOON.  
WINDS AND WAVES WILL LIKELY REMAIN JUST BELOW SCA CRITERIA FOR OUR  
NRN LAKE HURON NEARSHORE AREAS THRU TONIGHT AS THE FRONT STALLS IN  
THAT VCNTY. SCT/NMRS SHOWERS WILL CONTINUE TO IMPACT ALL NEARSHORE  
AREAS THRU TONIGHT AS THE COLD FRONT STALLS JUST WEST OF MICHIGAN.  
WINDS AND WAVES WILL DIMINISH BY THURSDAY AS SURFACE RIDGING BUILDS  
INTO MICHIGAN...WITH A RETURN TO DRY WEATHER AS WELL.  
 

 
   
APX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LH...NONE.  
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ323-341-  
342.  
 
SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR LMZ344>346.  
 
LS...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ321.  
 

 
 

 
 
SHORT TERM...MLR  
LONG TERM...JPB  
AVIATION...ADAM  
MARINE...MLR  
 
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