362  
FXUS63 KAPX 292314  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
714 PM EDT MON MAY 29 2017  
   
UPDATE
 
 
ISSUED AT 704 PM EDT MON MAY 29 2017  
 
DIURNAL SHOWER/THUNDERSTORM ACTIVITY QUICKLY DISSIPATING THIS  
EVENING WITH LOWERING SUN ANGLE. SCATTERED SHOWERS MAY CONTINUE  
OVERNIGHT OVER EASTERN UPPER, TIED MORE CLOSELY WITH DEEPER  
MOISTURE AND UPPER FORCING, WITH JUST ISOLATED ACTIVITY FURTHER  
SOUTH. WINDS WILL BE ON THE DECREASE WITH SUNSET.  
 
LOWS TONIGHT GENERALLY IN THE UPPER 40S TO AROUND 50.  
 

 
   
NEAR TERM
 
(TONIGHT THROUGH TUESDAY)  
ISSUED AT 354 PM EDT MON MAY 29 2017  
   
..SCATTERED SHOWERS AGAIN ON TUESDAY
 
 
 
HIGH IMPACT WEATHER POTENTIAL...MINIMAL. CHANCE FOR A FEW  
THUNDERSTORMS THROUGH EARLY THIS EVENING.  
 
PATTERN SYNOPSIS/FORECAST...DEEP CLOSED LOW CONTINUES TO SPIN OVER  
NORTHERN LAKE SUPERIOR WITH CYCLONIC FLOW ENTRENCHED OVER THE UPPER  
GREAT LAKES REGION. SOMEWHAT OF A WRAPPED-UP DRY SLOT STRETCHES FROM  
THE LOWER OHIO VALLEY TO LAKE HURON AND BACK TO THE CENTER OF THE  
LOW, AS EVIDENT ON VISIBLE AND WATER VAPOR SATELLITE IMAGERY. DEEPER  
MOISTURE IS LOCATED OFF TO OUR WEST, AS EVIDENCED BY GRB AND MPX 12Z  
SOUNDINGS AND MORE EXTENSIVE CLOUD COVER OVER WISCONSIN AND  
MINNESOTA. A COUPLE LOBES OF VORTICITY ROTATING ACROSS NORTHERN  
MICHIGAN HAVE INTERACTED WITH AMPLE LOW LEVEL INSTABILITY (COURTESY  
OF STRONG LOW LEVEL LAPSE RATES UP TO 9.5 C/KM NEAR SAGINAW BAY) TO  
GENERATE ISOLATED TO SCATTERED SHOWERS AND STORMS AT TIMES. SOME  
BETTER 0-6KM WIND SHEAR OF 40-50 KNOTS ALLOWED FOR A FEW BETTER  
ORGANIZED CELLS AROUND ALPENA EARLIER THIS AFTERNOON. AS DAYTIME  
HEATING WANES TOWARDS EARLY EVENING, EXPECT THESE DIURNALLY DRIVEN  
SHOWERS TO LARGELY DISSIPATE ACROSS MOST OF NORTHERN LOWER, WITH  
SHOWER CHANCES OVERNIGHT FOCUSING MORE OVER EASTERN UPPER AND THE  
TIP OF THE MITT. DUE TO THE STRONG LOW LEVEL LAPSE RATES AND  
RESULTANT BOUNDARY LAYER MIXING, SOUTHWEST WINDS HAVE BEEN GUSTY  
THIS AFTERNOON SOUTH OF M-72. THE GUSTINESS WILL ALSO DIMINISH  
TOWARDS SUNSET.  
 
FAIRLY QUIET NIGHT AHEAD. CLOUD COVER EXPECTED TO GRADUALLY INCREASE  
TONIGHT AS THE UPPER LOW SLOWLY WOBBLES FARTHER NORTHEAST AND DRAGS  
SOME OF THE DEEPER MOISTURE OVER WI/MN INTO NORTHERN MI. HOWEVER, IT  
MAY TAKE SOME TIME FOR THE CLOUD COVER TO THICKEN UP/CONGEAL IF THE  
LOSS OF DAYTIME HEATING RESULTS IN SOME EROSION OF THE DAYTIME CU  
FIELD. REGARDLESS, CLOUDS WILL BE MORE EXTENSIVE ACROSS EASTERN  
UPPER AND NORTHWEST LOWER THAN DOWN TOWARDS SAGINAW BAY. ONGOING  
COLD AIR ADVECTION WILL CAUSE TEMPERATURES TO DROP INTO THE MID 40S  
TO LOW 50S ACROSS THE AREA BY TUESDAY MORNING.  
 
FOR TUESDAY, EXPECT MORE DIURNALLY-DRIVEN SCATTERED SHOWERS ONCE  
AGAIN AS THE UPPER LOW DRIFTS TOWARDS JAMES BAY. CHANCES WILL BE  
HIGHEST ACROSS EASTERN UPPER, WITH ONLY SLIGHT CHANCES FOR NORTHERN  
LOWER. COOLER TEMPERATURES AND LOWER DEWPOINTS DUE TO ONGOING CAA  
WILL RESULT IN EVEN LESS DAYTIME INSTABILITY, SO NOT ANTICIPATING  
THUNDERSTORMS. IT WILL AGAIN BE BREEZY WITH SW WINDS GUSTING TO  
AROUND 25 MPH OVER NORTHERN LOWER IN THE AFTERNOON. HIGHS WILL RANGE  
FROM THE 50S OVER EASTERN UPPER TO UPPER 60S NEAR SAGINAW BAY.  
 

 
   
SHORT TERM
 
(TUESDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 354 PM EDT MON MAY 29 2017  
   
..COOLER AND LESS ACTIVE
 
 
HIGH IMPACT WEATHER POTENTIAL: NONE.  
 
PATTERN FORECAST: BY TUESDAY NIGHT, VERTICALLY STACKED LOW PRESSURE  
CENTERED NEAR JAMES BAY THAT HAS PLAGUED NORTHERN MICHIGAN WITH  
OCCASIONALLY UNSETTLED WEATHER OVER THE SECOND HALF OF THE HOLIDAY  
WEEKEND WILL SLOWLY SHIFT NORTHWARD THROUGH THE MIDWEEK TIMEFRAME.  
LOW PRESSURE RE-ENERGIZES AND DROPS SOUTHWARD ACROSS THE NORTHERN  
GREAT LAKES LATE THIS WEEK INTO NEXT WEEKEND...POTENTIALLY BRINGING  
ANOTHER ROUND OF UNSETTLED WEATHER. SANDWICHED IN BETWEEN THE TWO  
PERIODS OF UNSETTLED WEATHER WILL BE AN EXPANSIVE AREA OF HIGH  
PRESSURE EXPECTED TO DROP FROM SOUTHWEST CANADA INTO THE NORTHERN  
PLAINS BEFORE GRADUALLY EXPANDING EASTWARD WEDNESDAY-THURSDAY,  
ULTIMATELY DRIVING OUR SENSIBLE WEATHER (OR LACK THEREOF) DURING THE  
MIDWEEK TIME FRAME.  
 
PRIMARY FORECAST CHALLENGES/CONCERNS: MAIN CONCERNS REVOLVE AROUND  
LINGERING POPS TUESDAY NIGHT INTO EARLY WEDNESDAY ALONG WITH  
TEMPERATURE TRENDS THROUGHOUT THE PERIOD.  
 
BROAD TROUGHING OVERHEAD CONTINUES TUESDAY NIGHT WITH AFOREMENTIONED  
LOW PRESSURE SPINNING ACROSS CENTRAL CANADA. WITH AN ABSENCE OF TRUE  
FORCING, ANY LINGERING SHOWERS TUESDAY EVENING SHOULD GRADUALLY  
DIMINISH BEYOND SUNSET WITH A LOSS OF DIURNAL PROCESSES. DESPITE  
MOSTLY CLOUDY SKIES OVERNIGHT, WEAK COLD AIR ADVECTION IS EXPECTED  
TO AID IN TEMPERATURES FALLING TO THE LOW-MID 40S FOR OVERNIGHT LOWS.  
 
THE BULK OF WEDNESDAY IS EXPECTED TO BE DRY, ALTHOUGH ONE LAST  
DISTURBANCE PINWHEELS AROUND THE PARENT LOW. THIS IS EXPECTED TO  
PROVIDE JUST ENOUGH SUPPORT WHEN COMBINED WITH RENEWED DIURNAL  
COMPONENTS TO PRODUCE A FEW ISOLATED SHOWERS ACROSS THE AREA. ANY  
PRECIP SHOULD BE FAR FROM WIDESPREAD WITH THE MAJORITY OF NORTHERN  
MICHIGAN REMAINING DRY, THUS ONLY SUPPORTING LOW END/SLIGHT CHANCE  
POPS. HIGH TEMPS SEVERAL DEGREES BELOW NORMAL...RANGING FROM THE  
MID-UPPER 50S NORTH OF THE BRIDGE TO THE LOW-MID 60S SOUTH.  
 
HIGH PRESSURE BEGINS TO EXPAND FROM THE WEST WEDNESDAY EVENING  
BRINGING ANY LINGERING SHOWER THREAT TO AN END. LITTLE OF CONCERN ON  
THURSDAY, EXCEPT FOR ANOTHER SLIGHT CHANCE OF SHOWERS ACROSS EASTERN  
UPPER, WITH THE REST OF THE AREA EXPECTED TO FEATURE PARTLY TO  
MOSTLY SUNNY SKIES AND HIGH TEMPERATURES CLIMBING BACK TO NEAR-  
NORMAL.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH MONDAY)  
ISSUED AT 354 PM EDT MON MAY 29 2017  
 
LONG RANGE MODELS ARE VARYING GREATLY, LOWERING CONFIDENCE THROUGH  
THIS FORECAST PERIOD. THE FORECAST PERIOD WILL BEGIN WITH SOME  
SHOWERS AND POSSIBLY EVEN A THUNDERSTORM OVER NORTHERN LOWER  
THURSDAY NIGHT THROUGH FRIDAY AFTERNOON WITH A WEAK AREA OF LOW  
PRESSURE OVERHEAD ALONG WITH AN UPPER LEVEL WAVE AND AMPLE MOISTURE.  
TOO MANY UNCERTAINTIES PAST THIS POINT, BUT BELIEVE IT'S SAFE TO SAY  
THERE WILL BE PERIODS OF MOSTLY CLOUDY TO CLOUDY SKIES THROUGHOUT  
THE PERIOD WITH BEST CHANCES OF RAIN BEING SUNDAY AS MODELS HAVE  
EITHER A SURFACE LOW OVER SOUTHERN LOWER MICHIGAN OR TROUGHS  
ASSOCIATED WITH A LOW PRESSURE SYSTEM OVER THE NEW ENGLAND AREA  
STRETCHING OVER NORTHERN MICHIGAN. HIGHS WILL GENERALLY BE IN THE  
MID TO UPPER 60S, WHILE LOWS WILL BE IN THE MID TO UPPER 40S.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)  
ISSUED AT 704 PM EDT MON MAY 29 2017  
 
GENERALLY VFR CONDITIONS THROUGH THE PERIOD. THERE POTENTIALLY  
COULD BE A PERIOD OF HIGHER END MVFR CIGS AT PLN LATER TONIGHT  
INTO TUESDAY MORNING. COLD AIR ALOFT ASSOCIATED WITH AN UPPER  
LEVEL TROUGH WILL CONTINUE TO PRODUCE MAINLY DIURNAL SHOWERS  
THROUGH THE DAY ON TUESDAY. ISOLATED SHOWERS THIS EVENING WILL  
DISSIPATE WITH SUNSET, WITH SCATTERED SHOWERS RE-DEVELOPING  
DURING THE DAY ON TUESDAY WITH BROKEN CIGS BETWEEN 3-5K. GUSTY  
SOUTHWEST WINDS THIS EVENING WILL DISSIPATE WITH SUNSET. WINDS  
WILL BE GUSTY ONCE AGAIN DURING THE DAY ON TUESDAY FROM THE WEST-  
SOUTHWEST, ALTHOUGH NOT AS STRONG AS MONDAY.  
 

 
   
MARINE
 
 
ISSUED AT 424 PM EDT MON MAY 29 2017  
 
TODAY'S GUSTY WINDS ARE EXPECTED TO DIMINISH THIS EVENING OVER  
THE NEARSHORE WATERS, SO HAVE TRIMMED BACK THE SCA EXPIRATION FOR  
LAKES MICHIGAN AND HURON TO 8 PM THIS EVENING.  
 
LOW PRESSURE JUST NORTH OF LAKE SUPERIOR WILL CONTINUE TO RESULT  
IN GUSTY WINDS AT TIMES THROUGH TUESDAY, MAINLY DURING THE  
DAYTIME HOURS. GUSTS MAY MARGINALLY REACH SMALL CRAFT ADVISORY  
CRITERIA ON LAKE MICHIGAN TUESDAY AFTERNOON. SHOWERS AND STORMS  
LATE THIS AFTERNOON WILL DIMINISH THROUGH EVENING. SCATTERED  
SHOWERS ARE POSSIBLE AGAIN ON TUESDAY.  
 

 
   
APX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ348-349.  
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-342-  
344>346.  
LS...NONE.  

 
 

 
 
UPDATE...JRK  
NEAR TERM...MEK  
SHORT TERM...MJG  
LONG TERM...TJL  
AVIATION...JRK  
MARINE...MEK  
 
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