850  
FXUS63 KAPX 261055  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
655 AM EDT WED SEP 26 2018  
   
NEAR TERM
 
(TODAY THROUGH TONIGHT)  
ISSUED AT 355 AM EDT WED SEP 26 2018  
   
..MUCH COOLER WITH LIGHT LAKE EFFECT RAIN SHOWERS
 
 
HIGH IMPACT WEATHER POTENTIAL...NONE EXPECTED.  
 
BIG AIRMASS CHANGE FROM YESTERDAY BEHIND OUR SURFACE COLD FRONT  
WHICH BLEW ACROSS THE REGION EARLIER THIS MORNING. IT WILL FEEL  
BRISK AND MUCH COOLER TODAY. COOL ENOUGH ALOFT (850 MB TEMPS OF  
ABOUT +1 C) TO PRODUCE A FEW LAKE EFFECT STREAMERS OFF OF LAKE  
MICHIGAN AND LAKE SUPERIOR THROUGH THE MORNING HOURS. SURFACE  
RIDGING POKING IN FROM THE WEST MAY TRY TO LIMIT ACTIVITY THIS  
AFTERNOON. WINDS GENERALLY WEST NORTHWEST THIS MORNING WILL SLOWLY  
BACK INTO THE WEST THROUGH THE DAY THEN EVENTUALLY SOUTHWEST  
TONIGHT. PERHAPS SOME LINGERING LAKE EFFECT TONIGHT IN SOUTHWEST  
FLOW FAVORED AREAS BUT MOISTURE THINS OUT SO HAVE BACKED POPS DOWN  
TO SLIGHT CHANCE. HAVE ALSO LOWERED MAX TEMPS SOMEWHAT WITH A  
RANGE FROM THE LOWER 50S NORTH TO THE LOWER 60S SOUTHEAST. LOWS  
TONIGHT TRICKY DUE TO CLOUD COVER QUESTIONS AND WHETHER WINDS  
FULLY DECOUPLE BUT GENERALLY UPPER 30S TO MID 40S EXPECTED.  
 

 
   
SHORT TERM
 
(THURSDAY THROUGH FRIDAY)  
ISSUED AT 355 AM EDT WED SEP 26 2018  
   
..COOL, BREEZY, AND SHOWERY
 
 
HIGH IMPACT WEATHER POTENTIAL...LOW END GALES POSSIBLE ON NORTHERN  
LAKE MICHIGAN THURSDAY.  
 
PATTERN SYNOPSIS/FORECAST...AS SURFACE HIGH PRESSURE STRETCHES OUT  
OVER THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY, SOUTHWEST RETURN  
FLOW WILL INCREASE ACROSS NORTHERN MICHIGAN. WEAK ISENTROPIC LIFT  
WILL DEVELOP OUT AHEAD OF AN APPROACHING COLD FRONT. LOW PRESSURE  
TREKKING THROUGH SOUTHERN ONTARIO IS PROGGED TO DRAG THAT COLD FRONT  
THROUGH NORTHERN MICHIGAN LATE THURSDAY NIGHT, EXITING SAGINAW BAY  
SHORTLY AFTER DAYBREAK FRIDAY. ANOTHER BLAST OF COOLER AIR WILL BE  
THE RESULT, AS 850MB TEMPERATURES FALL BELOW 0C BY FRIDAY EVENING.  
 
PRIMARY FORECAST CONCERNS...OCCASIONAL SHOWER CHANCES AND WINDS.  
 
WITH THE EXCEPTION OF EASTERN UPPER AND A PORTION OF NORTHWEST  
LOWER, MOST AREAS WILL STAY DRY DURING THE DAY THURSDAY WHILE HIGH  
PRESSURE SITS TO OUR SOUTH. EVENTUALLY UPPER TROUGHING AND WEAK  
ISENTROPIC LIFT WILL WIN OUT, SPREADING SHOWER CHANCES INTO THE  
NORTHWEST 1/3 OF THE FORECAST AREA BY MID AFTERNOON. THE ACTUAL  
FRONT WILL BEGIN TO MOVE THROUGH LATE EVENING INTO THE OVERNIGHT,  
BRINGING ADDITIONAL SHOWER CHANCES. RAINFALL AMOUNTS WILL BE HIGHER  
THE FARTHER NORTH ONE GOES, PERHAPS UPWARDS OF 0.25" OVER EASTERN  
UPPER. WINDS WILL BE THE OTHER MAIN CONCERN FOR THURSDAY AS LOW  
LEVEL WARM AIR ADVECTION RAMPS UP, WITH BOUNDARY LAYER MIXING UP TO  
~850MB. WINDS WILL BE STRONGEST OVER EASTERN UPPER AND FAR NORTHWEST  
LOWER AS A LOW LEVEL JET STRETCHES FROM NORTHERN LAKE MICHIGAN TO  
WHITEFISH BAY, PRODUCING WINDS UP TO ~35 KNOTS AT 925MB AND ~45  
KNOTS AT 850MB THURSDAY AFTERNOON. THESE AREAS MAY SEE GUSTS OF 30  
TO 35 MPH MIXING DOWN TO THE SURFACE FROM LATE MORNING THROUGH MID  
AFTERNOON.  
 
ADDITIONAL POCKETS OF WEAK MID-LEVEL ENERGY WILL RIPPLE THROUGH  
BEHIND THE COLD FRONT ON FRIDAY, TRIGGERING SOME SHOWERS ALONG WITH  
POSSIBLE LAKE ENHANCEMENT. FORECAST SOUNDINGS SHOW THE LOW LEVELS  
PROGRESSIVELY DRYING THROUGH THE AFTERNOON AS DIURNAL MIXING REACHES  
ITS PEAK, BUT EXPECT PLENTY OF RESIDUAL CLOUD COVER TO LINGER. NOT  
AS BREEZY AS THURSDAY, BUT IT WILL FEEL KIND OF RAW WITH SHOWERS AT  
TIMES AND TEMPERATURES LARGELY LOCKED IN THE 50S THANKS TO THE NW  
FLOW.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 355 AM EDT WED SEP 26 2018  
 
HIGH IMPACT WEATHER POTENTIAL...FROST POTENTIAL FRIDAY AND SATURDAY  
NIGHTS?  
 
COOL WEATHER LIES IN STORE FOR THE WEEKEND AS A BROAD UPPER TROUGH  
PIVOTS OVER THE GREAT LAKES REGION. DIMINISHING CLOUDS LATE FRIDAY  
NIGHT MAY LEAD TO SOME PATCHY INLAND FROST AS TEMPERATURES DIP INTO  
THE MID TO UPPER 30S. SURFACE HIGH PRESSURE WILL THEN PASS OVERHEAD  
SATURDAY INTO SATURDAY NIGHT. COMBINED WITH LIGHT WINDS, THIS WILL  
BE A MORE FAVORABLE SETUP FOR FROST...HOWEVER THIS POTENTIAL LOOKS  
COMPLICATED BY INCREASING MID LEVEL CLOUDS, ESPECIALLY LATE. CURRENT  
FORECAST CALLS FOR WIDESPREAD LOWS IN THE MID TO UPPER 30S. PLENTY  
OF MODEL VARIANCE THEREAFTER, BUT SUFFICE IT TO SAY THE PATTERN  
LOOKS UNSETTLED AND RATHER WET AT TIMES AS A BAROCLINIC ZONE LIFTS  
INTO NORTHERN MICHIGAN AND INTERACTS WITH PWATS CLIMBING ABOVE 1"  
THROUGH THE FIRST HALF OF THE WORK WEEK.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 638 AM EDT WED SEP 26 2018  
 
OVER LAKE INSTABILITY DRIVEN RAIN SHOWERS WILL BE THE RULE TODAY  
INTO TONIGHT...WITH RAIN SHOWERS IN THE VICINITY AT TIMES AT  
MBL...TVC AND EVENTUALLY PLN WITH A WESTERLY FLOW THAT BECOMES  
WEST SOUTHWEST TONIGHT. CIGS WILL VARY WITH MAINLY MVFR THROUGH  
THIS MORNING EVENTUALLY LIFTING TO VFR. WINDS WILL BE GUSTY AT  
TIMES TODAY THEN DIMINISH THIS EVENING.  
 

 
   
MARINE
 
 
ISSUED AT 355 AM EDT WED SEP 26 2018  
 
MARGINAL SMALL CRAFT WINDS/WAVES EXPECTED ACROSS ALL NEARSHORE  
WATERS THIS MORNING WITH A GRADUAL DIMINISHING TREND THIS  
AFTERNOON. ANOTHER ROUND OF GUSTY WINDS, REACHING AT LEAST SMALL  
CRAFT CRITERIA, IS POSSIBLE ON THURSDAY...PRIMARILY ON LAKE  
MICHIGAN WHERE THE GALE WATCH IS POSTED.  
 

 
   
APX WATCHES/WARNINGS/ADVISORIES
 
 
MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ016-019>021-  
025-031.  
LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ345>349.  
GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR  
LHZ345.  
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-341-  
342-344>346.  
GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR  
LMZ323-341-342-344>346.  
LS...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-322.  

 
 

 
 
NEAR TERM...AS  
SHORT TERM...MK  
LONG TERM...MK  
AVIATION...AS  
MARINE...AS  
 
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