690  
FXUS63 KAPX 221132  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
632 AM EST MON DEC 22 2014  
   
NEAR TERM
 
(TODAY THROUGH TONIGHT)  
ISSUED AT 321 AM EST MON DEC 22 2014  
   
..A PRETTY QUIET DAY
 
 
SYNOPTIC PATTERN AND OBSERVATIONS:  
 
EARLY THIS MORNING...PERIODIC LIGHT SNOW WAS AFFECTING EASTERN UPPER  
BUT WAS DEPARTING NE ALONG WITH THE ASSOCIATED WEAK RIPPLE IN THE  
MID LEVEL FLOW AND WAA. THE DEEPER MOISTURE AND FORCING WAS TOO FAR  
WEST OF HERE TO BRING ANYTHING SIGNIFICANT. ELSEWHERE...SKIES  
CONTINUE TO BE CLOUDY WITH A COMBINATION OF LOW AND HIGHER LEVEL  
CLOUD. DEEPENING AND STRENGTHENING SOUTHERLY WINDS WAS PUMPING SOME  
LOW LEVEL DRIER AIR FROM THE BACKSIDE OF NEW ENGLAND HIGH  
PRESSURE...UP INTO NRN LOWER ATTM. THE HIGHER CLOUD WAS ASSOCIATED  
WITH WITH ANOTHER MID LEVEL WAVE/IMPULSE RUNNING UP TOWARD SRN LAKE  
MICHIGAN. THE BACKSIDE OF THAT CLOUD IS EXPECTED TO CLEAR THE  
MANISTEE AREA/GTV BAY AREAS 7-9AM...BEFORE CONTINUING TO EXIT NE.  
 
SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:  
 
THE EASTERN UPPER PRECIP WILL END AROUND OR SHORTLY AFTER SUNRISE  
WITH THE DEPARTURE OF THE MID LEVEL RIPPLE INTO ONTARIO. THE LOWER  
LEVEL CLOUDS WILL CONTINUE TRY AND DISSIPATE WITH THE ADVECTION OF  
THE DRIER AIR THROUGH MAINLY NRN LOWER. THIS LOW LEVEL FLOW WILL BE  
BACKING TO MORE OUT OF THE SSE BY AFTERNOON...WHICH MAY LEAD TO  
ADDITIONAL LOW LEVEL CLOUDS OFF LAKE HURON WHERE THE LOW LEVEL TEMPS  
ARE ENOUGH TO WARRANT BETTER OVERLAKE INSTABILITY. IF THESE CLOUDS  
DO SUSTAIN THEMSELVES...THE CLOUDS WOULD BE FOCUSED UP INTO EASTERN  
UPPER WITH LITTLE IN THE WAY OF CLEARING. THE CLEARING...AND THERE  
IS HESITATION WHEN SUN IS EXPECTED...WOULD BE PRIMARILY IN NRN LOWER  
WHERE THE DRYING IS GREATEST. THIS WOULD OCCUR LATER THIS MORNING  
AND INTO THE AFTERNOON...AS THE HIGHER CLOUD FROM THE WAVE PUSHING  
INTO SRN LAKE MICHIGAN EXITS.  
 
WE WILL BE WATCHING FOR THE FIRST SUBSTANTIAL WAVE TO BRING  
ADDITIONAL AND MUCH THICKER CLOUD/PRECIP TO ARRIVE THIS EVENING  
(MORE ON THAT BELOW). THIS IS ASSOCIATED WITH STRONG PACIFIC ENERGY  
DIVING INTO THE BACKSIDE OF A DEEPENING AND POSSIBLY CLOSING OFF LOW  
IN THE CENTRAL PLAINS.  
 
HIGHS IN THE MIDDLE 30S TODAY.  
 

 
   
SHORT TERM
 
(TUESDAY THROUGH CHRISTMAS DAY)  
ISSUED AT 321 AM EST MON DEC 22 2014  
 
HIGH IMPACT WEATHER POTENTIAL: YOU NAME IT! REALLY STARTING TO FEEL  
THE POTENTIAL FOR A SEVERAL HOUR PERIOD OF SOME FREEZING RAIN AND  
SNOW FOR THE HIGH SPOTS/TIP OF THE MITT OF NORTHERN LOWER MONDAY  
NIGHT...WITH SOME SNEAKY POTENTIAL FOR SNOW ACCUMULATION AND PERHAPS  
SOME FREEZING RAIN AS WELL NORTH OF THE BRIDGE INTO TUESDAY MORNING.  
AFTER THAT...CONFIDENCE REMAINS LOW REGARDING SNOW/WIND POTENTIAL  
TOWARD CHRISTMAS EVE (WEDNESDAY EVENING) THROUGH CHRISTMAS  
MORNING...BUT THAT POSSIBILITY DOES APPEAR TO BE INCREASING.  
 
ANYONE HAVE A COIN I CAN FLIP? MIGHT BE JUST AS ACCURATE AS FORECAST  
"CONSENSUS" HEADING INTO THE HOLIDAY MIDWEEK PERIOD. STILL LOTS OF  
UNANSWERED QUESTIONS ABOUT THIS TIME RANGE...AND UNFORTUNATELY THIS  
IS THE PERIOD WHEN WE NEED THE MOST ANSWERS GIVEN LOTS OF FUN  
FESTIVITIES AND ASSOCIATED TRAVEL CONCERNS. THE GOOD NEWS IS THAT AT  
LEAST THE FIRST HALF OF THE EVENT IS BECOMING CLEARER BY THE MINUTE  
(AT LEAST IN MY MIND)...FEATURING A CONCERN REGARDING SOME SNEAKY  
SNOW ACCUMULATION POTENTIAL AND FREEZING RAIN NORTH OF THE BRIDGE  
MONDAY NIGHT INTO TUESDAY MORNING...AS WELL AS A SIMILAR CONCERN BUT  
JUST OF THE FREEZING RAIN VARIETY INTO THE HIGHER ELEVATION AREAS OF  
NORTHERN LOWER DURING THIS SAME TIME FRAME.  
 
THE PATTERN CHANGE UNDERWAY THROUGH THE LOWER 48 IS QUITE  
IMPRESSIVE...FEATURING TREMENDOUS PACIFIC JET ENERGY PLOWING INTO  
THE PACIFIC NORTHWEST AS I TYPE THIS...WITH THAT ENERGY GOING INTO  
THE RAPID AMPLIFICATION OF UPPER TROUGHING THROUGH THE PLAINS STATES  
TODAY...AND ASSOCIATED STRENGTHENING OF LEE CYCLOGENESIS (ALREADY  
WELL EVIDENT!) TOWARD THE MID MISSISSIPPI VALLEY INTO EARLY EVENING.  
THAT FEATURE WILL OCCLUDE FAIRLY QUICKLY INTO MONDAY NIGHT AND  
TUESDAY AS IT LIFTS NORTH INTO OUR NECK OF THE WOODS...WITH ALL EYES  
ON ADDITIONAL STRONG PACIFIC ENERGY DIVING THROUGH THE BACKSIDE OF  
THE OCCLUDING LEAD TROUGH... AND HELPING DEVELOP A NEUTRAL TO EVEN  
NEGATIVELY TILTED/CLOSED MID LEVEL RESPONSE SOMEWHERE OVER THE MID  
MISS VALLEY. THIS LATTER FEATURE IS THE ONE OF MOST CONTENTION...  
WITH NUMEROUS OUTCOMES POSSIBLE...AND JUST ABOUT ANY SINGLE ONE  
WITHIN REASON...THOUGH THE TRUE ENERGY PLAYER IN THIS WHOLE MESS HAS  
YET TO COME ASHORE JUST YET (THOUGH GOES WIND ANALYSIS DOES SEEM TO  
HAVE A DECENT HANDLE ON ITS STRENGTH).  
 
AS DISCUSSED YESTERDAY...IT ALL COMES DOWN TO TIMING AND JUST HOW  
FAR SOUTH OUR SECOND PIECE OF ENERGY DIGS...AND CONTINUE TO BELIEVE  
BASED ON CLIMO OF SUCH STRONG PACIFIC JETS THAT THIS THING WILL  
REALLY DIG SOUTHWARD TOWARD GULF COAST...WITH TREMENDOUS UPPER JET  
SUPPORT FAVORING RAPID CYCLOGENESIS SOMEWHERE TOWARD LA/MS. THAT  
FEATURE SHOULD THEN LIFT NORTH AND CONTINUE DEVELOPING...THOUGH THE  
RATE AT WHICH THAT HAPPENS AS WELL AS JUST HOW MUCH OCCLUSION CAN  
OCCUR (NEUTRAL VERSUS NEGATIVE TILT) MEANS EVERYTHING FOR OUR  
WEATHER LOCALLY. A LESS AMPLIFIED MID LEVEL WAVE RESPONSE MEANS A  
MORE OPEN WAVE LIKELY PASSING WELL TO OUR EAST...AND PERHAPS  
DELIVERING BASICALLY NO ADDITIONAL PRECIP CHANCES AFTER TUESDAY  
NIGHT...WHILE A MORE AMPLIFIED/CLOSED MID LEVEL SOLUTION SUGGESTS  
THE SURFACE LOW MAY WRAP BACK NORTHWESTWARD BENEATH ITS UPPER  
WAVE...FAVORING ANOTHER ROUND OF RAIN CHANGING TO SNOW ACROSS THE  
AREA (OR MAYBE EVEN JUST PLAIN RAIN THE ENTIRE EVENT).  
 
CONFUSED YET? I KNOW I AM...AND I LOOK AT WEATHER ALL THE TIME!  
LET'S START WITH THE HIGH CONFIDENCE STUFF. APPROACH OF LEAD CLOSED  
WAVE AND AXIS OF MID LEVEL DIFLUENCE AHEAD OF AN ELEVATED WARM  
FRONT SHOULD LEAD TO EXPANDING PRECIP COVERAGE FROM SOUTHWEST TO  
NORTHEAST MONDAY NIGHT. DEEPENING AND STRENGTHENING EASTERLY FLOW  
AHEAD OF THE OCCLUDING SURFACE LOW TO OUR WEST MAY SLOW THE  
NORTHWARD MARCH OF PRECIP THANKS TO DRIER AIR HANGING TOUGH...BUT  
THAT SAME FLOW WILL ALSO HELP KEEP SURFACE TEMPS AND THERMAL  
PROFILES COLDER THROUGH MUCH OF THE NIGHT. AS SUCH...AM QUITE  
CONCERNED ABOUT A PERIOD OF FREEZING RAIN OR EVEN A START AS ALL  
SNOW FOR THE HIGHLANDS AND TIP OF THE MITT COUNTIES...WHERE LIGHT  
ICE AND SNOW ACCUMULATION MAY MAKE FOR SOME SLICK TRAVEL AS SURFACE  
TEMPS HANG IN THE 30-32F RANGE. THAT IS ESPECIALLY TRUE FOR  
SECONDARY ROADS GIVEN MANY REMAIN COLD AND SNOW COVERED...MEANING  
THAT EVEN IF SURFACE TEMPS RISE ABOVE 32F...MICROSCALE PROCESSES ARE  
LIKELY TO DOMINATE AND PROVIDE SOME QUITE SLICK TRAVEL. AS FOR THE  
EASTERN U.P....BELIEVE INITIALLY DRY AIRMASS WILL SUPPORT A START AS  
SNOW...TRANSITIONING TO RAIN THROUGH THE NIGHT AND INTO TUESDAY  
MORNING...WITH FREEZING RAIN POSSIBLE AS WELL GIVEN EASTERLY FLOW  
AND TEMPS STRUGGLING TO AROUND 32F OFF SNOW-COVERED ONTARIO.  
WOULDN'T BE SHOCKED TO SEE A SNEAKY 1-3" OF SNOW FALLING IN SOME  
SPOTS...WITH A HEADLINE ALSO POSSIBLE GIVEN LIKELY SLICK TRAVEL  
CONDITIONS.  
 
ALL OF THAT MESS SHOULD END AS A WARM FRONT PASSES AND NORTHERN  
MICHIGAN BREAKS INTO THE "WARM" SECTOR ON TUESDAY. STILL...COULD BE  
SOME LINGERING FREEZING RAIN INTERIOR SPOTS OF EASTERN UPPER RIGHT  
ON INTO EARLY TUESDAY AFTERNOON...BUT WITH PRECIP ENDING FROM SOUTH  
TO NORTH AS PRONOUNCED DRY SLOTTING ARRIVES. WILL LIKELY SEE SOME  
PERIODS OF VERY LIGHT RAIN AND DRIZZLE AFTER THE WIDESPREAD PRECIP  
ENDS AS DEW POINTS CRUISE THROUGH THE 30S AND PLENTY OF SATURATION  
BELOW 800MB REMAINS...WITH FOG ALSO A CONCERN OVER COLD GROUND.  
HOWEVER...IT ISN'T IMPOSSIBLE THAT WE ALSO SEE SOME SNEAKY COOLER  
AIR FILTER BACK ACROSS THE AREA IN THE WAKE OF THE OCCLUDED FRONT  
PASSAGE TUESDAY NIGHT...WITH AT LEAST THE SMALL POTENTIAL FOR  
SURFACE TEMPS ACROSS HIGHER TERRAIN AREAS TO AGAIN SLIP BACK BELOW  
FREEZING. THAT TYPE OF SNEAKY SETUP WOULD CERTAINLY BE ON PAR WITH  
NORTHERN MICHIGAN'S STYLE THIS TIME OF YEAR.  
 
THEREAFTER...IT'S ALL DOWNHILL IN THE CONFIDENCE DEPARTMENT. FEEL  
REALLY COMPELLED TO CARRY A CONSENSUS FORECAST WITH CONTINUED  
CHANCES FOR RAIN INTO WEDNESDAY (AFTER A PROBABLE BREAK TUESDAY  
NIGHT)...CHANGING TO SNOW BEFORE ENDING CHRISTMAS MORNING. 00Z  
GUIDANCE SUITE NOT QUITE AS BAD AS THROWING DARTS...WITH A GFS/ECMWF  
CONSENSUS EMERGING...FEATURING A MORE EASTERLY TRACK THROUGH LAKE  
HURON...SUGGESTIVE OF POSSIBLE ACCUMULATING WET SNOW OVER AT LEAST  
PART OF THE CWA. NOT ALL GUIDANCE AGREES WITH THE P-GFS TRACKING  
OVERHEAD...NAM OFF THE VIRGINIA COAST (HUH?)...AND GGEM NOT CHANGING  
ALL THAT MUCH. HAVE TO BELIEVE THE TRUTH LIES IN THE MIDDLE/EASTERN  
SOLUTIONS...WITH A SURFACE LOW TRACKING UP LAKE HURON (CLIMO-FAVORED  
AREA) WHILE DEEPENING...SUGGESTING (AS OUR FORECAST HAS FOR SEVERAL  
DAYS) RAIN INITIALLY CHANGING TO SNOW AS THICKNESSES CRASH INTO THE  
BACKSIDE OF ELONGATING DEFORMATION-DRIVEN PRECIP AXIS. AS SUCH...THE  
POSSIBILITY STILL EXISTS FOR A FEW HOUR PERIOD OF SOME VERY WET  
ACCUMULATING SNOW AND GUSTIER WINDS JUST AS WE HEAD INTO THE WEE  
HOURS OF CHRISTMAS MORNING.  
 

 
   
LONG TERM
 
(THURSDAY THROUGH SUNDAY)  
ISSUED AT 321 AM EST MON DEC 22 2014  
 
ACTIVE PATTERN EXPECTED TO CONTINUE THOUGH THE SPECIFIC DETAILS ARE  
FAR FROM SET IN STONE. WILL BE WATCHING OUR NEXT UPPER WAVE EJECTING  
OUT OF THE RELOADING WESTERN CONUS TROUGH...BRINGING THE POTENTIAL  
FOR SNOW SOMEWHERE NEARBY...THOUGH WITH SOME GUIDANCE MEMBERS ALSO  
SUGGESTING A MORE AMPLIFIED SCENARIO WHICH COULD EVEN BRING MORE  
RAIN. HAVE MY DOUBTS ABOUT THAT AS THE COLD AIR/BAROCLINICITY IN  
WESTERN/CENTRAL CONUS TROUGH SETUPS TYPICALLY LAYS OUT OVER THE  
LOWER LAKES...BUT SOMETHING TO WATCH AS WE GET CLOSER. AFTER  
THAT...IT REALLY LOOKS LIKE AN OVERALL SHIFT IN THE MEAN UPPER  
PATTERN...DRIVEN IN PART BY OUR MIDWEEK SYSTEM SORT OF THROWING THE  
ATMOSPHERIC CIRCULATION FOR A LOOP. CONFIDENCE IN INCREASING THAT WE  
WILL SEE AN ABRUPT RETURN TO MUCH MORE TYPICAL LATE DECEMBER/EARLY  
JANUARY WEATHER...FEATURING BROAD UPPER TROUGHING ENCOMPASSING MUCH  
OF THE CENTRAL AND EASTERN CONUS...BRINGING OF COURSE THE LIKELIHOOD  
FOR LAKE EFFECT SNOWS AND THE OCCASIONAL CLIPPER SYSTEM OR TWO.  
TIMING IS EVERYTHING...WITH LITTLE CONSENSUS AT THIS RANGE. THUS...  
CHANCE WORDING WILL DO FOR DAILY SNOW SHOWER CHANCES...WITH TEMPS AT  
OR EVEN A LITTLE BELOW NORMAL INTO NEXT WEEKEND. STAY TUNED...  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 626 AM EST MON DEC 22 2014  
   
..VFR WITH DETERIORATING CONDITIONS TONIGHT
 
 
LOWER LEVEL DRY AIR HAS PUNCHED IT'S WAY THROUGH THE AIRPORTS  
OVERNIGHT...WITH MAINLY MID AND UPPER LEVEL CLOUDS AROUND. THESE  
CLOUDS WILL EXIT FROM SW TO NE THROUGH THE MORNING HOURS WITH A  
LIKELY PERIOD OF MOSTLY SUNNY SKIES...BEFORE ADDITIONAL UPPER  
LEVEL CLOUDS STREAM IN LATER TODAY. THIS EVENING DEEPER MOISTURE  
AND RAIN STARTS TO MOVE INTO MBL/TVC...THEN SNOW AT PLN/APN CLOSER  
TO MIDNIGHT AND AFTER. SNOW IS EXPECTED TO CHANGE TO RAIN AT APN  
LATE. SNOWFALL RATES LOW WITH MINIMAL ACCUMULATIONS EXPECTED THERE  
(LESS THAN AN INCH). THE MORE SE TURN TO THE WINDS COULD ALLOW FOR  
MVFR STRATUS TO REAPPEAR AT APN EARLIER...THIS AFTERNOON/EVENING.  
 
CIGS WILL DROP TO LESS THAN 1KFT HEADING THROUGH THE NIGHT AT ALL  
TAF SITES...WITH VSBYS GENERALLY MVFR...BUT PERIODICALLY IFR AT  
PLN IN SNOW.  
 
WINDS WILL TURN MORE SE THROUGH THE DAY AND NIGHT...GENERALLY  
6-9KTS. SOME GUSTS REACHING THE TEENS AT TIMES DURING THE DAY.  
 

 
   
APX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LH...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST TUESDAY  
FOR LHZ345>349.  
 
LM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST TUESDAY  
FOR LMZ323-342-344>346.  
 
SMALL CRAFT ADVISORY UNTIL 7 PM EST TUESDAY FOR LMZ341.  
 
LS...SMALL CRAFT ADVISORY UNTIL 7 PM EST TUESDAY FOR LSZ321.  
 

 
 

 
 
NEAR TERM...SMD  
SHORT TERM...LAWRENCE  
LONG TERM...LAWRENCE  
AVIATION...SMD  
 
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