458  
FXUS63 KAPX 260448  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
1148 PM EST TUE NOV 25 2014  
   
SYNOPSIS
 
 
ISSUED AT 347 PM EST TUE NOV 25 2014  
 
LAKE EFFECT SNOW SHOWERS WILL PERSIST ACROSS PARTS OF NORTHERN  
MICHIGAN THIS AFTERNOON INTO THE OVERNIGHT HOURS. COLDER  
TEMPERATURES ALONG WITH ADDITIONAL CHANCES FOR SNOW WILL CONTINUE  
ALL THE WAY THROUGH THE REMAINDER OF THE HOLIDAY WEEK INTO THE FIRST  
PART OF THE WEEKEND.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH TONIGHT)  
ISSUED AT 347 PM EST TUE NOV 25 2014  
 
ALWAYS A FUN CHALLENGE DURING THIS TIME OF YEAR AND INDEED TONIGHT  
IS NO EXCEPTION...WITH THE MAIN FORECAST ISSUE BEING THE PLACEMENT  
OF CLOUDS/LINGERING LAKE SNOW CHANCES AS WELL AS JUST HOW COLD TEMPS  
MAY GET IN SOME AREAS. EARLY AFTERNOON ANALYSIS PLACES A STRONG SUB-  
980MB LOW RACING NORTHEASTWARD INTO NEWFOUNDLAND BUT WITH PRONOUNCED  
LOW LEVEL TROUGHING STRUNG BACK SOUTHWARD INTO THE GREAT LAKES AREA.  
ALOFT...AN UPPER WAVE IS NOTED LIFTING THROUGH SOUTHEASTERN  
ONTARIO...WITH EARLIER DEEPER MOISTURE/DEFORMATION FORCING FROM THIS  
FEATURE DELIVERING QUITE THE SHOT OF SNOWFALL FOR MANY AREAS  
OVERNIGHT (SAVE FOR EAST/SOUTHEAST COUNTIES). VISIBLE SATELLITE AND  
STREAMLINE ANALYSIS PLACE STRONG LOW LEVEL CYCLONIC FLOW OVER  
NORTHERN MICHIGAN...THOUGH WEAKENING WITH TIME...WHICH HAS  
INTERACTED WITH DEPARTING DEEP MOISTURE AND PLENTIFUL LAKE  
INSTABILITY TO GENERATE A SMATTERING OF HEAVIER LAKE SNOW BANDS...  
PARTICULARLY INTO FAR NORTHWEST CHIPPEWA COUNTY AS WELL AS MUCH OF  
NORTHWEST LOWER.  
 
THE PRIMARY CHALLENGE FOR TONIGHT IS JUST HOW MUCH SNOW SHOWER  
ACTIVITY WILL CONTINUE. SAID CYCLONIC FLOW WILL WANE QUICKLY THROUGH  
THE EVENING AS LOW LEVEL RIDGING WORKS THROUGH THE LOWER  
LAKES...HELPING GRADUALLY BACK OUR INITIAL NORTHWEST FLOW BACK TO  
THE SOUTHWEST TOWARD MORNING...THOUGH WITH SPEED SHEAR OF LESS THAN  
10 KNOTS. THAT SETUP MORE THAN NOT OFTEN LEADS TO SOME SNEAKY  
MESOSCALE PROCESSES THAT MAKE THE FORECAST DIFFICULT. IN THIS  
CASE...SUSPECT THAT WE WILL MAINTAIN WESTERLY FLOW LAKE SNOWS AS THE  
WINDS BEGIN TO BACK THE FIRST HALF OF THE NIGHT...BUT PROBABLY WITH  
A TREND TOWARD CLEARING INLAND AREAS AS WE LOSE THE FLOW AND LAND  
BREEZES ATTEMPT TO SET UP.  
 
ALL THE WHILE...PRONOUNCED THERMAL TROUGHING LOOKS TO LAY OUT  
THROUGH THE STRAITS AND DOWN ACROSS LAKE MICHIGAN...POTENTIALLY  
INTERACTING WITH SAID LAND BREEZES TO HELP SPIN UP A MESOSCALE  
VORTEX OR TWO OVER THE LAND/WATER INTERFACE. HI-RES GUIDANCE HAS  
BEEN INSISTENT ON THIS OCCURRING UP TOWARD THE TIP OF THE MITT  
COUNTIES...WHERE WEAK LOW LEVEL SOUTHWEST FLOW INTERACTS WITH BACKED  
FLOW THROUGH THE STRAITS TO FORCE STRONGER CONVERGENCE INTO PARTS OF  
EMMET COUNTY...AND PERHAPS DOWN THE SHORE OF LAKE MICHIGAN COUNTIES.  
WHILE CONFIDENCE IS RATHER LOW...DO SUSPECT SOME SNEAKY HEAVIER  
AMOUNTS ARE POSSIBLE WHERE AND IF THIS FEATURE DEVELOPS. FOR MOST  
OTHER AREAS...SUSPECT THERE COULD BE SOME QUITE CHILLY LOW TEMPS  
WITH SOME CLEARING EXPECTED AND FRESH SNOW COVER. HAVE UNDERCUT ALL  
GUIDANCE (AWAY FROM COASTAL LOCALES)...WITH THE POSSIBILITY THAT  
SOME SPOTS COULD TANK WELL INTO THE SINGLE DIGITS. DEFINITELY A VERY  
NEAR TERM ISSUE BUT THE POSSIBILITY IS THERE FOR A FEW UNLUCKY SPOTS  
TO PUSH ZERO...PROVIDED OF COURSE WE CAN MANAGE SOME CLEARING.  
   
LONG TERM
 
(WEDNESDAY THROUGH TUESDAY)  
ISSUED AT 347 PM EST TUE NOV 25 2014  
 
HIGH IMPACT WEATHER POTENTIAL: SEASONALLY ACTIVE NOVEMBER PATTERN  
WITH SEVERAL SNOW CHANCES /GENERALLY LIGHT/ BUT SOME POTENTIAL  
TRAVEL ISSUES.  
 
LOW LEVEL RIDGING ATTEMPTS TO MOVE INTO THE GREAT LAKES ON  
WEDNESDAY. OVERNIGHT LAND BREEZES...PLENTY OF OVER-LAKE INSTABILITY  
/850MB TEMPS -11C/ AND WEAK LOW LEVEL FLOW ALL POINT TOWARD MESO-  
VORTICES ACROSS LAKE MICHIGAN AND LAKE HURON. VARIOUS PIECES OF  
GUIDANCE POINT TO THIS AS WELL. VERY LOW CONFIDENCE IN TRYING TO  
PIN DOWN THE DETAILS OF THESE FEATURES BUT WILL GENERALLY HAVE  
HIGHER POPS ACROSS NORTHERN LAKE MICHIGAN TOWARD WESTERN MACKINAC  
COUNTY...AS WELL AS ALONG LAKE HURON. DRY OVER INLAND AREAS WITH  
SOME PARTIAL SUNSHINE POSSIBLE...AT LEAST FOR A PORTION OF THE DAY.  
 
WEDNESDAY NIGHT-THANKSGIVING...FORECAST BECOMES MORE MUDDLED AND  
CHALLENGING AS NORTHERN STREAM SHORTWAVE SLIDES INTO THE NORTHERN  
LAKES AND HELPS TO ENHANCED EXISTING LAKE-INDUCED TROUGHING.  
INCREASE IN DEEPER SYNOPTIC MOISTURE WILL WORK WITH WEAK LOW LEVEL  
SOUTHWEST FLOW TO ENHANCE THE SNOW FROM FAR NORTHWEST LOWER THROUGH  
THE TIP OF THE MITT INTO THE STRAITS. TO FURTHER COMPLICATE  
THINGS...GUIDANCE ALSO HINTING AT ENHANCEMENT POTENTIAL OFF OF LAKE  
HURON WITH LIGHT ONSHORE/DRAINAGE FLOW...SOME AGGREGATE SURFACE  
TROUGHING UP ALONG THE COAST AND POSSIBLY A MESO-VORTEX SLIDING  
ONSHORE. SNOW SHOWERS WILL INCREASE ACROSS MUCH OF THE AREA LATE  
WEDNESDAY NIGHT INTO THANKSGIVING ALONG THE BOUNDARY SLIDING  
THROUGH THE AREA. HIGH CONFIDENCE THAT MOST OF NORTHERN MICHIGAN  
SHOULD SEE A PERIOD OF SNOW WITH FRONT...PROBABLY ON THE ORDER OF  
1-2" /H7 MIXING RATIOS AROUND 1 G/KG/ WITH HIGHER AMOUNTS IN  
ENHANCED AREAS. AS DEEPER SYNOPTIC MOISTURE STRIPS OUT...A QUICK  
TRANSITION TO NW FLOW LAKE EFFECT OCCURS. NOT EXPECTING BIG  
ACCUMULATIONS BUT ADDITIONAL MINOR ACCUMULATIONS POSSIBLE IN  
FAVORED SNOW BELTS. MAY ALSO HAVE A PERIOD OF SOME GUSTY WINDS  
/15-20 MPH/ BEHIND THE FRONT CREATING AREAS OF BLOWING SNOW AND  
REDUCED VISIBILITIES. ALL IN ALL...A FAIRLY WINTRY THANKSGIVING  
DAY ACROSS NORTHERN MICHIGAN.  
 
THURSDAY NIGHT AND FRIDAY...ACTIVE AND CHALLENGING WEATHER CONTINUES  
AS LONGWAVE PATTERN FLATTENS OUT WITH ADDITIONAL PACIFIC ENERGY  
MOVING INTO THE UPPER MIDWEST. SOME LINGERING LIGHT LAKE EFFECT  
CLOSER TO THE LAKE MICHIGAN COAST THURSDAY NIGHT AS LOW LEVEL FLOW  
BACKS TO THE SOUTHWEST. AN IMPRESSIVE PUSH OF WARM AIR  
ADVECTION/UPGLIDE SNOWS DEVELOPING ON FRIDAY AS WARM FRONT LIFTS  
TOWARD THE SOUTHERN LAKES AND WEAK SURFACE LOW APPROACHES FROM THE  
WEST. PLENTY COLD ENOUGH H8 TEMPS FOR CONTINUED LAKE ENHANCEMENT  
OVER PORTIONS OF LAKE MICHIGAN.  
 
EXTENDED PERIODS...(FRIDAY NIGHT THROUGH MONDAY)  
 
FRIDAY NIGHT: FAIRLY DECENT SHOT OF WARM AIR ADVECTION SNOW  
CONTINUES TO PUSH NORTH AND EAST INTO SOUTHERN CANADA...WITH THE  
LAST OF ANY LINGERING LIGHT SNOW PUSHING THROUGH THE STRAITS/EASTERN  
UPPER BY 12Z SATURDAY.  
 
SATURDAY THROUGH SATURDAY NIGHT: FAIRLY LOW CONFIDENCE DURING THIS  
PERIOD AS MODEL SPREAD IS QUITE LARGE REGARDING THE MAGNITUDE OF  
WARMER AIR RETURNING TO THE REGION ON SATURDAY. WITH THE RECENT  
IMPROVEMENTS TO THE SNOW PACK ACROSS ALL OF NORTHERN MICHIGAN...  
WOULDN'T BE SURPRISED TO SEE ANOTHER WAFFLE OR TWO IN TERMS OF THE  
DEGREE OF WARM AIR...BUT WILL HEDGE TOWARD A RELATIVELY MILDER  
SOLUTION WITH HIGHS INTO AT LEAST THE MIDDLE 30S.  
 
SUNDAY THROUGH MONDAY: SURPRISE SURPRISE...A RETURN TO RATHER COLD  
AIR IS EXPECTED BEHIND A COLD FRONT EXTENDING SOUTHWARD FROM SURFACE  
LOW PRESSURE CENTERED NEAR JAMES BAY BY SUNDAY MORNING WITH ANY  
MIXED PRECIP TRANSITIONING OVER TO ALL SNOW BEFORE ENDING. WITH THAT  
COLD AIR COMES ANOTHER CHANCE FOR ACCUMULATING LAKE EFFECT SNOW  
EARLY NEXT WEEK.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1145 PM EST TUE NOV 25 2014  
 
VFR/HIGH MVFR CONDITIONS ARE EXPECTED AT ALL NRN LWR MICHIGAN TAF  
SITES THRU WEDNESDAY NIGHT AS HIGH PRESSURE REMAINS IN CONTROL.  
SOME LINGERING LIGHT LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO  
FALL OVER PORTIONS OF NW AND FAR NRN LWR MICHIGAN (PLN/TVC/MBL)  
OVERNIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR WEDNESDAY AS LOW  
LEVEL WINDS SHIFT AROUND TO THE S/SE AHEAD OF OUR NEXT LOW  
PRESSURE SYSTEM. THIS SYSTEM WILL INCREASE CHANCES OF LAKE ENHANCED  
SNOW LATER WEDNESDAY NIGHT AND CONTINUING INTO THANKSGIVING.  
LIGHT/CALM WINDS OVERNIGHT WILL BECOME EASTERLY UNDER 10 KTS ON  
WEDNESDAY.  
 

 
   
MARINE
 
 
ISSUED AT 347 PM EST TUE NOV 25 2014  
 
STRONGER NORTHWEST WINDS WILL DIMINISH QUICKLY THIS EVENING AS HIGH  
PRESSURE ARRIVES OVER THE WATERS...WITH THAT LIGHTER FLOW PREVAILING  
THROUGH WEDNESDAY NIGHT. A STRONG COLD FRONT IS EXPECTED TO ARRIVE  
WITH A BURST OF SNOW AND GUSTY NORTHWEST WINDS EARLY THURSDAY...BUT  
NO GALES ARE FORESEEN. A PERIOD OF STRONGER SOUTHWEST WINDS IS  
LIKELY LATER FRIDAY AND THROUGH THE WEEKEND...WITH A LOW END CHANCE  
FOR A FEW GALE GUSTS.  
 

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

 
 

 
 
SYNOPSIS...MJG  
SHORT TERM...LAWRENCE  
LONG TERM...KEYSOR/GILLEN  
AVIATION...MLR  
MARINE...LAWRENCE  
 
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