FXUS63 KAPX 262108
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
407 PM EST SAT DEC 26 2009

.SYNOPSIS.../ISSUED AT 407 PM/

A STORM SYSTEM OVER THE CENTRAL PLAINS...WILL LIFT NORTH INTO THE 
STATE TONIGHT AND SUNDAY. THIS SYSTEM WILL EXIT NORTHEAST INTO 
QUEBEC MONDAY. THIS FEATURE WILL GENERATE...SOME LIGHT SNOW OVER THE 
NORTHERN LAKES REGION...TONIGHT INTO NEXT WEEK.

&&

.SHORT TERM.../UPDATE ISSUED AT 407 PM/...TONIGHT

OCCLUDED AND STACKED LOW PRESSURE SYSTEM CONTINUES TO SPIN OVER THE 
UPPER MISSISSIPPI RIVER VALLEY THIS AFTERNOON. BROADER AREA OF 
Q-VECTOR CONVERGENCE/QG-UPWARD FORCING ALONG THE S/SW PORTION OF THE 
LOW IN THE PROCESS OF ROTATING UP THROUGH NRN LOWER MICHIGAN... 
SPREADING AN AREA OF WIDESPREAD BUT GENERALLY LIGHT SNOWFALL INTO 
THE REGION. BROAD AREA OF FORCING PRIMARILY THE RESULT OF STRONG 
DEEP LAYER FRONTOGENESIS OCCURING ALONG THE TIGHT THERMAL GRADIENT 
THAT IS ROTATING AROUND THIS SYSTEM. BEEFY LAKE ENHANCED SNOW 
SHOWERS ROTATING OFF LAKE MICHIGAN INTO THE GRB AREA ON A BACKING SE 
FLOW (ALONG WITH A HINT OF A LAKE INDUCED VORTICE). BUT OF MORE 
CONCERN FOR THIS CWA IS THE BROAD AREA OF LAKE ENHANCEMENT NOW 
IMPACTING THE GRR FORECAST AREA. 

TONIGHT...AREA OF QG-UPWARD FORCING WILL CONTINUE TO PIVOT UP 
THROUGH THE REGION TONIGHT AS STACKED LOW PRESSURE CENTER SLOWLY 
WORKS INTO NORTH CENTRAL LAKE MICHIGAN BY SUNDAY MORNING. THIS ALONE 
EXPECTED TO BRING AN INCH OR TWO OF ACCUMULATIONS TO MOST AREAS 
TONIGHT. MORE DIFFICULT PART OF THE FORECAST IS THE AFOREMENTIONED 
LAKE ENHANCEMENT NOW DOWN ACROSS THE GRR FORECAST AREA. AS STACKED 
LOW AND ASSOCIATED LOW LEVEL CONVERGENCE AXIS PIVOTS INTO THE 
REGION...GUIDANCE CONTINUES TO HINT AT POTENTIAL FOR BEEFIER LAKE 
ENHANCED SNOWS TO SLIDE UP INTO THE MANISTEE/BENZIE COUNTY 
AREA...LATER THIS EVENING AND OVERNIGHT WHILE LOW LEVEL WINDS TURN 
ONSHORE (SW) BY SUNDAY MORNING. COMBINATION OF DECENT SYNOPTIC 
FORCING/PLENTY OF OVER WATER INSTABILITY AND INVERSION HEIGHTS 
CREEPING UP TO OVER 700 MB IS WORRISOME. ONLY DOWNSIDE IS THE FACT 
THAT LOW LEVEL FLOW REMAINS UNFAVORABLE THROUGH AT LEAST THIS 
EVENING WHICH SHOULD KEEP THE HEAVIER STUFF OFFSHORE FOR AWHILE. 
SO...WILL NOT PULL THE TRIGGER ON ANY HEADLINES AT THIS POINT.

ADAM   

&&

.LONG TERM.../ISSUED AT 407 PM/...SUNDAY AND BEYOND

SUNDAY...WILL SEE HOW THIS PANS OUT, BUT THE LOW CONTINUES TO MOVE 
OVER N LOWER BY 00Z WITH THE CORE OF THE 500 MB LOW, GETTING TO EAST 
SIDE OF THE STATE. SO THIS WILL CONTINUE THE PROBABLY SCATTERED SNOW 
SHOWERS WITH THE WEAKENING LOW WITH THE FILLING OVER THE REGION. THE 
SFC LOW IS NOW EXPECTED TO BE NEAR JAMES BAY WITH A PRETTY DECENT 
SFC TROUGH OVER MICHIGAN. THIS PUTS US INTO A PRETTY DECENT NNW FLOW 
WITH UPWARD MOTION AND DELTA TS OF 12-13C. WITH THE UPWARD MOTION 
AND THE HIGH RH IN THE 850-700 MB LAYER (RH>70%) WILL EXPECT LAKE 
ENHANCED SNOW, PROBABLY LIGHT ACCUMULATIONS. WOULD LIKE TO SEE THE 
DELTA T TO BE A LITTLE HIGHER FOR MODERATE TO HEAVY ACCUMULATIONS. 

SUNDAY NIGHT...LES LOOKS TO BE THE BEST BET AS THE 850 MB 
TEMPERATURES ARE AROUND -10C AND GET COLD WITH TIME. THE PROBLEM IS 
THAT THE MODELS ARE CONTINUING TO SHOW THAT THE WINDS WILL BE  
SHIFTING FROM WNW TO ALMOST NNW PRETTY QUICKLY AND VERY FOR MOST OF 
THE NIGHT. THEY DON'T SEEM TO SETTLE LIKE THEY DID IN YESTERDAY'S 
RUNS, SO WILL GO WITH LIGHT ACCUMULATIONS DUE TO NO DOMINATE BANDS 
FROM SHIFTING WIND DIRECTIONS. 

MONDAY...WE HAVE GOOD WINDS AND GOOD TEMPERATURES, FOR LAKE EFFECT. 
SO WILL PROBABLY HAVE SOME SNOW BANDS, BUT THE AMOUNTS WILL PROBABLY 
BE LIGHT AT BEST, WITH BOTH THE GFS, AND NAM SHOWING THAT THE 
850-700 MB LAYER RH IS LESS THAN 40% AFTER 18Z. THIS MAY NOT SQUASH 
THE LAKE CONVECTION, BUT IT WILL PUT A DAMPER ON HAVING ANY HEAVIER 
AMOUNTS FOR THE AFTERNOON. 

MONDAY NIGHT...THE WINDS CONTINUE FROM THE NNW STEADILY, BUT WITH 
WHAT THE GFS SAYS IS RH VALUES IN THE 850-700 MB LAYER WILL BE 
AROUND 50% THIS DOESNT' BODE WELL FOR STRONG SNOW BANDS, BUT IT IS 
BETTER THAN THE OTHER DAY. SO WE WILL PROBABLY GET LIGHT 
ACCUMULATIONS, BUT NOT SURPRISED, IF SOME MORE MODERATE 
ACCUMULATIONS POP IN. SOME OF THE MOISTURE MOVES OUT IN THE SW 
COUNTIES AND WOULDN'T BE SURPRISED IF THERE IS SOME CLEARING IN THE 
SW BY THE MORNING. 

TUESDAY...500 MB HEIGHTS BUILD WITH THE SFC HIGH BUILDING INTO THE 
REGION. SO WILL GO WITH THE CHANCE OF SNOW SHOWERS FOR THE MORNING. 
OF COURSE, THE MODELS CHANGE FROM DAY TO DAY. NOW THE WARM ADVECTION 
AND ANTICYCLONIC TURNING WHICH OCCURS DURING THE DAY, THEN TURNS 
CYCLONIC SW FLOW WITH SOME INCREASING MOISTURE IN THE 850-700 MB 
LAYER, DELTA TS OF 12-13C AND UPWARD MOTION ESPECIALLY OVERNIGHT, 
WILL EXPECT SOME SW FLOW LAKE BANDS POSSIBLE. WOULD EXPECT AT THIS 
POINT THAT THEY WILL BE MINOR TO LIGHT ACCUMULATIONS ALONG THE LAKE 
SHORE.   

EXTENDED (WEDNESDAY THROUGH SATURDAY)...WEDNESDAY, THE HIGH MOVES TO 
THE EAST AND A WARM FRONT MOVES THROUGH UPPER MICHIGAN. WITH ANOTHER 
500MB WAVE MOVING OUT OF THE CENTRAL ROCKIES. THE BULK OF WEDNESDAY 
WILL BE DRY, BUT THERE IS A CHANCE FOR SOME SNOW WITH THE FRONT AND 
THE 500 MB WAVE. THURSDAY, THE NEXT SYSTEM AND COLD FRONT WILL MOVE 
THROUGH THE REGION AND LOOKS LIKE IT WILL KICK OFF SNOW. THE 500 MB 
SHORTWAVE TRAILING THE FRONT WILL HELP TO KEEP THE SNOW GOING. 
FRIDAY, MORE ENERGY DIVES INTO THE 500 MB TROUGH. WHILE THE MAIN 
ENERGY WILL BE CLOSER TO THE EAST COAST, THE LOWS CORE WILL BE IN 
WISCONSIN, ALLOWING FOR MORE SNOW SHOWERS AS IT PUSHES INTO MICHIGAN 
BY THE EVENING. SATURDAY, A BIT OF A QUESTION MARK HERE AS THE MAIN 
ENERGY WILL BE ON THE EAST COAST WITH THE NEXT NOR'EASTER. HOWEVER, 
THERE IS SOME 500 MB ENERGY LEFT OVER THE WESTERN GREAT LAKES. THE 
ONE THING THAT WOULD INHIBIT PRECIPITATION IS THE DRY NE FLOW INTO 
THE WESTERN LAKES. THE NE WIND WOULD PUSH SNOW INTO THE GRB AREA OF 
NEAR MKE. WILL HAVE TO WATCH THIS, BUT THERE IS A CHANCE OF SNOW 
SHOWERS FOR US. 

JSL

&&

.MARINE.../ISSUED AT 407 PM/

WINDS GO CALM OVERNIGHT AS THE LOW TRACKS OVER N LAKE MICHIGAN AND 
THE GRADIENT SLACKENS. ONCE THE LOW MOVES OFF TO THE NORTHEAST, WILL 
EXPECT THE WINDS TO INCREASE GRADUALLY THROUGH MONDAY. LOOKS LIKE WE 
WILL BE IN HIGH SMALL CRAFT TYPE WINDS LATE ON MONDAY AS THE NW 
WINDS INCREASE. RIGHT NOW THE MODEL GUIDANCE ONLY GUST TO AROUND 30 
KNOTS.

JSL

&&

.AVIATION.../ISSUED AT 1238 PM/...VALID FOR 18Z TAFS

CLOUDS CONT TO INCREASE OVER THE NRN LAKES THRU THE PERIOD AS
MSTR LIFTS NORTH INTO THE REGION...IN RESPONSE TO SFC AND UPPER 
LEVEL FEATURES LOCATED OVER THE CENTRAL PLAINS. VFR CIGS AND VSBYS 
AT KPLN/APN TO DIMINISH TO MVFR THIS AFTN AS MSTR INCREASES...
WHILE MVFR CIGS AND VSBYS LINGER AT KTVC. NO PCPN TYPE PROBLEMS 
EXPECTED THRU THE TAF PERIOD...WITH LIGHT SNOW ACROSS ALL OF 
NRN MI THRU SUNDAY AFTERNOON. SOUTHEAST WINDS INTO THIS EVENING 
WILL SHIFT SOUTHWEST SUNDAY...IN ADVANCE OF CENTRAL PLAINS STORM 
SYSTEM LIFTING NORTH INTO THE NRN LAKES.
  
SWR

&&

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

&&

$$