794  
FXUS63 KAPX 191924  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
324 PM EDT THU JUL 19 2018  
   
NEAR TERM
 
(THROUGH TONIGHT)  
ISSUED AT 322 PM EDT THU JUL 19 2018  
   
..QUIET WEATHER CONTINUES WITH INCREASING CLOUDINESS
 
 
HIGH IMPACT WEATHER POTENTIAL: NONE.  
 
PATTERN SYNOPSIS/FORECAST: HIGH PRESSURE CENTERED OVER THE EASTERN  
GREAT LAKES WILL PROVIDE MOSTLY CLEAR SKIES (MINUS SOME HIGH CIRRUS  
CLOUDS AND FAIR WEATHER CUMULUS), LIGHT WINDS, AND A PLEASANT  
EVENING. ANY FAIR WEATHER CUMULUS CLOUDS THAT DEVELOPED DURING  
DIURNAL HEATING WILL QUICKLY DISSIPATE AS THE SUN ELEVATION  
DECREASES THROUGH THE LATE AFTERNOON/EARLY EVENING HOURS. WINDS WILL  
ALSO DECOUPLE THIS EVENING...PROVIDING LIGHT AND VARIABLE WINDS FOR  
THE OVERNIGHT HOURS. A DEVELOPING LOW PRESSURE SYSTEM AND  
ACCOMPANYING UPPER LEVEL LOW OVER THE DAKOTAS WILL PUSH IN BEHIND  
SAID DEPARTING HIGH PRESSURE...INCREASING CLOUDINESS THROUGHOUT THE  
NIGHT ALONG WITH SHOWER CHANCES BEGINNING DURING THE EARLY MORNING  
HOURS FRIDAY, INCREASING FROM SOUTHWEST TO NORTHEAST. AFOREMENTIONED  
572MB UPPER LOW WILL CUT OFF OVER WISCONSIN FRIDAY MORNING WITH  
DEEPER MOISTURE ON SOUTHERLY WINDS (FORECAST SOUNDINGS HAVE PWATS  
NEARING 1.50" BY 12Z OVER THE MBL AREA). DRY AIR ASSOCIATED WITH  
SAID HIGH PRESSURE WILL IMPINGE ON APPROACHING MOISTURE, IMPEDING  
THE MOISTURE FROM ADVANCING QUICKLY. THIS SAID, BELIEVE ONLY CHANCES  
OF RAIN SHOWERS BY THE END OF THIS FORECAST PERIOD (12Z) WILL BE  
NEAR MBL...IF IT EVEN ARRIVES BY THEN. FORESEE A SCENARIO OF HIGHER  
BASED LOW CLOUDS WITH SPRINKLES AND/OR VERY LIGHT RAIN DURING ONSET  
OF PRECIPITATION.  
 
LOWS TONIGHT WILL BE IN THE UPPER 50S TO NEAR 60. WINDS WILL BE  
LIGHT AND VARIABLE THROUGHOUT THE NIGHT AND BECOMING SOUTHEASTERLY 5-  
10MPH AROUND DAYBREAK.  
 

 
   
SHORT TERM
 
(FRIDAY THROUGH SUNDAY)  
ISSUED AT 322 PM EDT THU JUL 19 2018  
   
..A DAMP COUPLE OF DAYS
 
 
HIGH IMPACT WEATHER POTENTIAL...MINIMAL.  
 
PATTERN SYNOPSIS/FORECAST...A SLOW MOVING, VERTICALLY STACKED LOW  
HAS CUT OFF FROM THE JET STREAM. PROGRESSION WITH THIS SYSTEM WILL  
BE SLOW AND WILL AFFECT THE UPPER GREAT LAKES THE NEXT TWO DAYS.  
FRIDAY WILL START OFF DRY AS THE SYSTEM MOVES DOWN THE UPPER  
MISSISSIPPI VALLEY, AND THEN BEGINS TO ACROSS SOUTHERN WISCONSIN AND  
INTO C LOWER BY 00Z/SAT. THIS WILL BRING RAIN INTO THE FORECAST AREA  
DURING THE MORNING AND SPREAD ACROSS DURING THE AFTERNOON. MODELS  
STALL THE LOW OVER THE REGION FOR ABOUT 24 HOURS BEFORE PUSHING IT  
SSE IN THE OHIO VALLEY BY 12Z/SUNDAY. STABILITY IN THE MID LEVELS,  
BASED ON THE SHOWALTER INDEX (850 MB), EXPECTING 0C TO -1C ON THE  
MODELS, SO THUNDER IS POSSIBLE, BUT SHOWERS MORE LIKELY. PWAT VALUES  
ARE EXPECTED TO RISE, AS THE LOW MOVES OVER THE REGION, TO AROUND  
1.70".  
 
PRIMARY FORECAST CONCERNS...WITH US IN THE D0-D1 DROUGHT STATUS, AND  
IT LOOKS LIKE WE ARE EXPECTING A DECENT LONG DURATION DAMPNESS, WITH  
OCCASIONAL SHOWERS, AT LEAST IN N LOWER. AS GOOD AS THIS LOOKS, WILL  
ERR ON THE SIDE OF CAUTION, THAT EVEN THOUGH THE SYSTEM LOOKS TO BE  
READY TO SOAK THE REGION, SOME AREAS DO RUN THE RISK OF MISSING OUT,  
IF THE MODELS ARE WRONG ABOUT THE PATH. HOWEVER, IT LOOKS PROMISING.  
 

 
   
LONG TERM
 
(SUNDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 322 PM EDT THU JUL 19 2018  
   
..AROUND NORMAL, GIVE OR TAKE
 
 
 
EXTENDED (SUNDAY THROUGH THURSDAY)...THE STACKED LOW CONTINUES TO  
MOVE TO THE SOUTH OF THE REGION ON SUNDAY, PULLING THE MOISTURE WITH  
IT. AS IT MOVES OUT, A SUBSEQUENT SHORTWAVE RIDGE MOVES INTO THE  
REGION ON MONDAY. THE RIDGE MOVES OUT ON TUESDAY, BUT A DYING COLD  
FRONT MOVES INTO THE REGION. THE MODELS DON'T SHOW MUCH WITH A VERY  
BROKEN LINE OF PRECIPITATION, THEN DRYING OVERNIGHT. WEDNESDAY LOOKS  
TO REMAIN DRY UNTIL THE LATE AFTERNOON, AS A 500 MB LOW SINKS SOUTH  
FROM HUDSON BAY, AND BRINGS SOME MUCH COOLER AIR. ONCE THE COLDER  
AIR SINKS IT, SOME DIURNAL RAIN SHOWERS WILL BE POSSIBLE WHICH LOOK  
TO FALL APART OVERNIGHT. THE MODELS DISAGREE ON THURSDAY WITH THE  
CHANCE FOR RAIN (ECMWF) OR DRY (GFS). BETTING ON THE DRIER  
CONDITIONS UNTIL A REAL PATTERN CHANGE, WHICH COULD BE IN THE  
OFFING IN THE 8-14 DAY OUTLOOK FROM CPC.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 124 PM EDT THU JUL 19 2018  
 
LIGHT AND VARIABLE WINDS WILL TURN SOUTHERLY TODAY (BUT REMAIN  
LIGHT) WITH A GOOD LIKELIHOOD OF LAKE BREEZES THIS AFTERNOON,  
WHICH IS ALREADY EVIDENT AT APN. VFR CONDITIONS THROUGH THE TAF  
PERIOD AS FAIRLY SUNNY SKIES SEE INCREASINGLY HIGHER LEVEL CLOUDS  
THROUGH THE DAY. CLOUDS THICKEN TONIGHT AS A LOW PRESSURE SYSTEM  
NEARS FROM THE WEST, RESULTING IN INCREASED CHANCES FOR SHOWERS  
TO ENTER MBL BY 12Z AND TVC CLOSER TO THE END OF THE TAF PERIOD.  
LOW-LEVEL DRY AIR WILL SLOW THE ADVANCING RAIN SHOWERS AS THEY  
TRY TO SPREAD TOWARDS THE NORTHEAST. SOME LLWS OVER MBL AND TVC  
BETWEEN THE HOURS OF AROUND 06-13Z WITH WINDS AT 2KFT OF 35KTS  
FROM 160 DEGREES.  
 

 
   
MARINE
 
 
ISSUED AT 322 PM EDT THU JUL 19 2018  
 
TONIGHT THROUGH SATURDAY...WINDS FOR MOST OF THE REGION LOOK TO  
REMAIN BELOW SMALL CRAFT CRITERIA THROUGH SATURDAY, WITH THE ONLY  
EXCEPTION BEING, LAKE HURON FRIDAY NIGHT AND SATURDAY AS THE SFC LOW  
MOVES INTO THE REGION WITH A FAIRLY TIGHT GRADIENT. THE WINDS SHOULD  
DIMINISH AS WE GET INTO SATURDAY AFTERNOON, WITH THE SFC LOW SINKING  
TO THE SOUTH, ALLOWING THE PRESSURE GRADIENT TO RELAX.  
 

 
   
APX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LH...NONE.  
LM...NONE.  
LS...NONE.  

 
 

 
 
NEAR TERM...TL  
SHORT TERM...JL  
LONG TERM...JL  
AVIATION...TL  
MARINE...JL  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MI Page Main Text Page