400  
FXUS63 KAPX 282032 CCA  
AFDAPX  
 
AREA FORECAST DISCUSSION...CORRECTED  
NATIONAL WEATHER SERVICE GAYLORD MI  
332 PM EST SUN FEB 28 2021  
   
NEAR TERM
 
(THROUGH MONDAY)  
ISSUED AT 328 PM EST SUN FEB 28 2021  
   
..MUCH COLDER AIR AND LAKE SNOW SHOWERS RETURNING
 
 
HIGH IMPACT WEATHER POTENTIAL: COLDER AIR SPILLS INTO THE REGION  
TONIGHT LEADING TO SINGLE DIGIT WIND CHILLS FOR MONDAY.  
ACCUMULATING LAKE EFFECT SNOW SHOWERS FOR THE SNOWBELTS.  
 
PATTERN SYNOPSIS/FORECAST: 20Z SATELLITE/COMPOSITE ANALYSIS  
REVEALS OUR OPEN SHORT-WAVE CIRCULATION ROLLING THROUGH NORTHERN  
WISCONSIN. ASSOCIATED SLOWLY DEEPENING SURFACE LOW PRESSURE IS  
PASSING THROUGH THE IRON MOUNTAIN AREA HEADING TOWARD THE EASTERN  
U.P. WITH 3 HOUR PRESSURE FALLS CENTERED ACROSS THAT AREA. AXIS  
OF DEFORMATION/F-GEN FORCED SNOWFALL CONTINUES TO PIVOT THROUGH  
WESTERN/CENTRAL UPPER MICHIGAN ALONG THE N/NW SIDE OF THE  
WAVE/SURFACE LOW. EXPANSIVE WARM CONVEYOR BELT/AXIS OF RAINFALL  
STRETCHES FROM OKLAHOMA ENE ACROSS THE MID ATLANTIC.  
 
MUCH OF LOWER MICHIGAN STILL SITTING IN "NO-MANS" LAND OF SORTS  
BETWEEN AXIS OF SNOW TO THE NORTH AND RAIN TO THE SOUTH. LOWER  
CLOUD COVER HAS EXPANDING UP THROUGH OUR AREA AND THERE IS SOME  
SHOWERY/DRIZZLY LOOKING RETURNS ON RADAR SLIDING UP THROUGH  
NORTHERN LOWER MICHIGAN WITH A LITTLE BETTER COVERAGE IN EASTERN  
UPPER. BUT IN ALL, PRECIP ACROSS THIS CWA HAS BEEN PALTRY THUS  
FAR.  
 
THROUGH THIS EVENING: SHORT-WAVE AND SURFACE LOW WILL TRACK  
ACROSS EASTERN UPPER MICHIGAN OVER THE NEXT SEVERAL HOURS, BACK-  
SIDE DEFORMATION AXIS JUST SKIRTING THROUGH EASTERN UPPER MICHIGAN  
THROUGH EARLY- MID EVENING. GIVEN THE FURTHER NORTH TRACK OF THE  
LOW, PRECIP ACROSS E.UP. WILL LIKELY REMAIN MAINLY LIQUID THROUGH  
EARLY EVENING ANYWAY UNTIL COLDER AIR BEGINS TO FOLD BACK INTO THE  
REGION RESULTING IN A FEW HOURS OF LIGHT ACCUMULATING SNOW.  
 
SOUTH OF THE BRIDGE, SPOTTY RAIN SHOWERS WILL CONTINUE TO MOVE  
THROUGH NORTHERN LOWER MICHIGAN THROUGH EARLY-MID EVENING WITH  
MAYBE A BRIEF TRANSITION OVER TO SNOW BEFORE ENDING.  
 
SYSTEM CONTINUES QUICKLY INTO EASTERN CANADA TONIGHT. HIGHER  
IMPACTS FOLLOW WITH SUBSTANTIALLY COLDER AIR SPILLING INTO THE  
STATE ON GUSTY NORTHWEST WINDS...LATER TONIGHT THROUGH MONDAY.  
THIS WILL DRIVE TEMPERATURES DOWN INTO THE TEENS BY MONDAY MORNING  
WITH ONLY MODEST REBOUNDING ANTICIPATED DURING THE DAY MONDAY. BUT  
GUSTY WINDS WILL RESULT IN SINGLE DIGIT ABOVE AND BELOW ZERO WIND  
CHILL READINGS MONDAY MORNING, QUITE THE CHANGE FROM WHERE HAVE  
BEEN OVER THE LAST FEW DAYS.  
 
LAKE SNOWS ARE ANOTHER MATTER. STRONG COLD ADVECTION TONIGHT  
DRIVES H8 TEMPS DOWN TO -18C TO -22C THROUGH MONDAY RESULTING IN  
LAKE INDUCED CAPE VALUES OF NEAR 500 J/KG ON MICHIGAN AND A LITTLE  
BETTER STILL ON SUPERIOR (BUFKIT SUGGESTS A PERIOD OF MODERATE TO  
EXTREME LAKE EFFECT CONDITIONS ON MONDAY). INCOMING AIRMASS WILL  
BE ON THE DRIER SIDE HOWEVER, WITH SINGLE DIGIT DEWPOINTS AND PWAT  
VALUES UNDER 0.10", WHICH MIGHT THROTTLE LAKE EFFECT TO SOME  
DEGREE. BUT THINK WE WILL BE ABLE TO MUSTER SOME MODERATE SNOW  
ACCUMULATIONS IN THE SNOWBELTS. ALONG WITH GUSTY WINDS AND BLOWING  
SNOW, WE MAY NEED TO HOIST AN ADVISORY FOR MONDAY.  
 

 
   
SHORT TERM
 
(MONDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 328 PM EST SUN FEB 28 2021  
 
HIGH IMPACT WEATHER POTENTIAL: MINIMAL  
 
PATTERN SYNOPSIS/FORECAST:  
 
RIDGING MAKES A RETURN TO THE GREAT LAKES FOR THE START OF THE SHORT  
TERM...AS STRONG, ANOMALOUS TROUGHING DEPARTS (SOME WOULD SAY, GOOD  
RIDDANCE). AS WE GET INTO HIGH PRESSURE ON THE BACK SIDE OF THIS  
TROUGHING...LAKE EFFECT SHOULD BE WINDING DOWN AS TEMPS ALOFT  
RISE...AND POTENTIAL FOR DIMINISHING CLOUD COVER WITH STILL QUITE  
COLD AIR ALOFT SHOULD LEAD TO ONE MORE VERY COLD NIGHT BEFORE THINGS  
WARM UP AGAIN TUESDAY. A WEAK NORTHERN STREAM SHORTWAVE WILL BE THE  
NEXT THING TO WATCH GOING INTO LATE TUESDAY AND EARLY  
WEDNESDAY...WITH A MORE POTENT SHORTWAVE STAYING WELL TO OUR  
SOUTH...AND THAT TROUGHING FROM MONDAY, STILL ANOMALOUS AS IT SPINS  
OFF THE COAST OF NOVA SCOTIA (HOLD THAT THOUGHT TILL THE LONG TERM).  
BY WEDNESDAY...UPSTREAM FLOW OVER THE PACIFIC BECOMES MORE  
AMPLIFIED...WITH TROUGHING DIGGING SOUTH OF ALASKA AS RIDGING BEHIND  
IT STRENGTHENS...SETTING THE SCENE FOR A CUTOFF LOW TO GET KICKED  
EASTWARD INTO SOUTHERN CALIFORNIA. AS TROUGHING DIGS TOWARD THE  
WESTERN NORTH AMERICAN COAST...WILL SEE RIDGING ACROSS THE WEST-  
CENTRAL US BEGIN TO AMPLIFY WEDNESDAY...LENDING A SLIGHT TROUGHY  
LOOK TO EASTERN PORTIONS OF THE US.  
 
PRIMARY FORECAST CONCERNS: LINGERING LES, COLD TEMPS/CLOUD COVER  
MONDAY NIGHT...GUSTY WINDS AND PRECIP CHANCES TUESDAY INTO WEDNESDAY.  
 
AS SHORTWAVE DEPARTS EASTWARD MONDAY NIGHT...WILL SEE PRESSURE  
GRADIENT BEGIN TO SLACKEN AS SURFACE HIGH PRESSURE BUILDS IN. THIS  
SHOULD ACT TO DECREASE WINDS FOR A TIME. WILL SEE MID-LEVEL  
SUBSIDENCE MOVE IN DURING THE NIGHT...WHICH SHOULD LEAD TO A  
DECREASE IN CLOUD COVER. RECENT GUIDANCE SEEMS TO BE TRENDING THINGS  
A TAD WARMER FOR MONDAY NIGHT...THOUGH THERE IS STILL A PRETTY  
REASONABLE CHANCE FOR SOME LOCATIONS TO BOTTOM OUT BELOW NORMAL  
MONDAY NIGHT. AFOREMENTIONED MID-LEVEL SUBSIDENCE SHOULD ALSO HELP  
BRING LES CHANCES TO A CLOSE THROUGH THE NIGHT AS INVERSION HEIGHTS  
FALL. CAN'T RULE OUT IT LINGERING LONGER INTO THE NIGHT  
NORTH/NORTHWEST FLOW LAKE EFFECT ACROSS EASTERN UPPER AND PERHAPS  
NEAR OR RIGHT OFF THE SUNRISE COAST OF NORTHERN LOWER...WHERE 850 TS  
LOOK TO STAY COLD ENOUGH THROUGH AT LEAST 6Z.  
 
AS NORTHERN STREAM SHORTWAVE (AKA, CLIPPER SYSTEM) APPROACHES FROM  
THE NORTHWEST TUESDAY...WILL SEE MOISTURE INCREASE FROM TOP DOWN.  
HOWEVER...AT THE SAME TIME...SOUTHWESTERLY FLOW WILL BE RAMPING UP  
AS WELL...BETWEEN DEPARTING SURFACE HIGH TO OUR SOUTHEAST AND LOW  
MOVING THROUGH SOUTHERN MANITOBA/ONTARIO...WITH A LOT OF DRY AIR  
STILL IN THE MIDLEVELS...AND GULF MOISTURE KEPT BUSY TO OUR SOUTH BY  
POTENT SHORTWAVE MOVING THROUGH THE SOUTHERN STREAM OF THE FLOW  
ACROSS THE GULF COAST STATES. PRECIPITATION MAY HAVE A HARD TIME  
REACHING THE GROUND...THOUGH MAY HAVE A SLIGHTLY BETTER CHANCE  
FURTHER NORTH ACROSS EASTERN UPPER, AND MAYBE THE TIP OF THE MITT,  
WHERE SYNOPTIC MOISTURE FROM THE CLIPPER WILL BE STRONGER, AND WHERE  
BETTER DYNAMICS WILL BE LOCATED. WILL AT LEAST SEE SOME INCREASED  
CLOUD COVER...BUT BIGGER NEWS WILL BE WARMER TEMPERATURES AS SYSTEM  
DRAGS A WARM FRONT THROUGH THE REGION THROUGH THE DAY.  
ADDITIONALLY...WITH STRENGTHENING PRESSURE GRADIENT BETWEEN SURFACE  
HIGH AND INCOMING LOW...WILL LIKELY SEE WINDS PICK UP AGAIN DURING  
THE DAY TUESDAY...LEADING TO ANOTHER GUSTY DAY...THOUGH WARM  
ADVECTION WILL BE IN PLAY THIS TIME AROUND.  
 
LATEST MODEL RUNS MAY BE TRENDING PERHAPS A LITTLE COOLER FOR  
WEDNESDAY THAN THEY HAVE THE LAST FEW DAYS...WITH THAT NORTHERN  
STREAM SYSTEM DRAGGING A WEST-TO-EAST-ORIENTED COLD FRONT INTO THE  
GREAT LAKES. WILL HAVE TO KEEP HALF AN EYE ON THIS FOR TEMPERATURE  
TRENDS...THOUGH AT LEAST FOR NOW, IT LOOKS TO STAY DRY.  
 

 
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH SUNDAY)  
ISSUED AT 328 PM EST SUN FEB 28 2021  
 
HIGH IMPACT WEATHER POTENTIAL: MINIMAL...?  
 
REMEMBER WHEN I SAID TO HOLD THAT THOUGHT ABOUT MONDAY'S TROUGHING  
LINGERING OFF NOVA SCOTIA? WELL, THAT PESKY BUGGER MAY END UP  
HELPING TO BOOKEND OUR WEEK WITH COLDER WEATHER...AS IT LOOKS TO  
LINGER NEAR THE ST. LAWRENCE RIVER/NOVA SCOTIA THROUGH THE  
WEEK...AND ACTUALLY ATTM APPEARS TO RETROGRADE FOR A TIME, SWINGING  
SOME LOBES OF COLDER AIR INTO THE GREAT LAKES PERHAPS EVEN AS EARLY  
AS WEDNESDAY NIGHT. PERHAPS COLD ENOUGH AIR ALOFT TO BRING LES  
CHANCES BACK INTO THE PICTURE...ESPECIALLY IF IT PANS OUT THAT THE  
DOWNSTREAM TROUGH WILL SEND LITTLE LOBES OF ENERGY KNOCKING ON OUR  
NORTHERN DOOR THROUGH THE END OF THE WEEK INTO NEXT WEEKEND. AS  
SUCH, WILL HAVE TO WATCH FOR ANOTHER INCURSION OF COLD AIR FOR  
FRIDAY INTO SATURDAY AS NORTHERLY FLOW COULD BE CONTINUALLY  
REINFORCED ACROSS THE GREAT LAKES REGION FOR THE LAST HALF OF THE  
WEEK.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)  
ISSUED AT 219 PM EST SUN FEB 28 2021  
 
DEEPENING SURFACE LOW PRESSURE IS ADVANCING ENE THROUGH CENTRAL  
UPPER MICHIGAN AND WILL CROSS EASTERN UPPER MICHIGAN THROUGH EARLY  
EVENING. AHEAD OF THE LOW, MVFR-IFR CLOUD COVER HAS SPREAD BACK  
INTO NORTHERN MICHIGAN OVER THE LAST SEVERAL HOURS. SOME SPOTTY  
SHOWERS ARE OUT THERE AS WELL. BUT COVERAGE HAS/IS MUCH LESS THAN  
ANTICIPATED. JUST LOWER CLOUD COVER AND GUSTY LOW LEVEL WINDS  
THROUGH THE AFTERNOON AS THE LOW PASSES THROUGH THE REGION, WITH  
WINDS VEERING FROM SE TO SW BY EARLY EVENING AND ON AROUND TO NW  
THIS EVENING.  
 
BEHIND THE SYSTEM, SUBSTANTIALLY COLDER AIR SPILLS INTO NORTHERN  
MICHIGAN TONIGHT INTO MONDAY. THIS WILL KICK ON THE LAKE EFFECT  
SNOW MACHINE WITH SNOW SHOWERS BECOMING COMMON ACROSS THE  
SNOWBELTS LATER TONIGHT AND MONDAY. TVC/MBL WILL HAVE THE BIGGEST  
IMPACT. GUSTY WINDS AND FALLING SNOW WILL LIKELY RESULT IN REDUCED  
VSBYS THERE.  
 

 
   
MARINE
 
 
ISSUED AT 328 PM EST SUN FEB 28 2021  
   
..BACK INTO A GUSTY PERIOD OF TIME ON THE LAKES
 
 
WINDS WILL VEER AROUND TO THE NORTHWEST THIS EVENING AND INCREASE.  
MIGHT BE A SHORT PERIOD OF GALE FORCE GUSTS ON LAKE MICHIGAN THIS  
EVENING. BUT A LONGER PERIOD OF GALE GUSTS WILL BE FOUND ON  
NORTHERN LAKE HURON TONIGHT THROUGH MONDAY. GALE WARNINGS WILL  
REMAIN INTACT AS IS.  
 
WINDS WILL DIMINISH MONDAY NIGHT. BUT ANOTHER ROUND OF GUSTY WINDS  
IS POSSIBLE TUESDAY WITH GALE FORCE GUSTS POSSIBLE ON LAKE  
MICHIGAN.  
 

 
   
APX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LH...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 9 PM EST MONDAY  
FOR LHZ345-349.  
GALE WARNING FROM 6 PM THIS EVENING TO 9 PM EST MONDAY FOR  
LHZ347-348.  
SMALL CRAFT ADVISORY UNTIL 3 AM EST TUESDAY FOR LHZ346.  
LM...SMALL CRAFT ADVISORY UNTIL 9 PM EST MONDAY FOR LMZ323-344>346.  
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 9 PM EST MONDAY  
FOR LMZ341-342.  
LS...NONE.  

 
 

 
 
NEAR TERM...ADAM  
SHORT TERM...FEF  
LONG TERM...FEF  
AVIATION...ADAM  
MARINE...ADAM  
 
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