FXUS63 KAPX 261738
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1238 PM EST SAT DEC 26 2009

.SYNOPSIS.../ISSUED AT 232 AM/

AN AREA OF LOW PRESSURE WILL SLOWLY ROTATE EASTWARD ACROSS THE GREAT 
LAKES THROUGH SUNDAY WITH COLDER AIR FILTERING BACK INTO THE REGION. 
AFTER SOME EARLY MORNING FREEZING DRIZZLE TODAY...PERIODS OF LIGHT 
SNOW CAN BE EXPECTED THROUGH SUNDAY. SNOW SHOWERS WILL REMAIN LIKELY 
INTO EARLY NEXT WORK WEEK...AS THE LAKE EFFECT MACHINE CRANKS UP 
AGAIN WITH A SECONDARY SURGE OF COLD AIR ARRIVING ON MONDAY. 

&&

.SHORT TERM.../UPDATE ISSUED AT 1128 AM/...TODAY

OCCLUDED AND STACKED LOW PRESSURE SYSTEM CONTINUES TO SPIN OVER THE 
IOWA/WISCONSIN/ILLINOIS BORDER THIS MORNING. SFC OCCLUDED FRONT NOW 
NORTH OF THE CWA /STRETCHED ACROSS LAKE SUPERIOR INTO ONTARIO/ WHILE 
COLDER AIR HAS OVERSPREAD THE REGION FROM THE S/SW. NRN LOWER AND 
EASTERN UPPER MICHIGAN CATCHING A BIT OF A BREAK THIS MORNING...WITH 
A WEDGE OF DRY AIR AND CLR-PTCLDY SKIES SLICING UP THROUGH THE 
REGION. HOWEVER...POCKET OF Q-VECTOR CONVERGENCE/QG-UPWARD FORCING 
WILL BE SLIDING UP THROUGH THE LOWER PENINSULA THIS AFTERNOON 
THROUGH TONIGHT AS THE STACKED LOW SLOWLY WORKS IT/S WAY INTO NRN 
MICHIGAN...THE PRIMARY RESULT OF STRONG DEEP LAYER FRONTOGENESIS 
OCCURING ALONG THE TIGHT THERMAL GRADIENT THAT IS ROTATING AROUND 
THIS SYSTEM. DEEPER MOISTURE AND AREA OF LIGHT SNOWFALL ASSOCIATED 
WITH THIS FORCING HAS BEEN STEADILY ROTATING NORTHWARD INTO PORTIONS 
OF NW LOWER MICHIGAN THIS MORNING. MEANWHILE...SOME BEEFIER LAKE 
ENHANCED SNOW SHOWERS ARE LOCATED OUT OVER LAKE MICHIGAN BUT WILL 
IMPACT PRIMARILY THE WISCONSIN/WESTERN UPPER MICHIGAN SHORELINE 
AREAS AS THE LOW LEVEL FLOW BACKS S-SE THROUGH THE DAY.

SO FOR US...HAVE STEADILY INCREASING POPS FROM S-N THIS AFTERNOON 
THROUGH TONIGHT AS AFOREMENTIONED FORCING/LIGHT SNOWFALL WORKS UP 
THROUGH THE REGION...AND TOTAL ACCUMULATIONS OF A FEW INCHES AT 
BEST. COULD SEE SOME LAKE HURON ENHANCED SNOW SHOWERS EVENTUALLY 
IMPACT AREAS AROUND DRUMMOND ISLAND LATER THIS AFTERNOON THROUGH 
TONIGHT...AS DEEPER MOISTURE AND COLD AIR GET OVER THE LAKE. WILL 
SEE...AS LOW LEVEL FLOW MAY BE JUST A LITTLE TO SOUTHERLY FOR THIS 
OCCUR.

ADAM 

&&

.LONG TERM.../ISSUED AT 408 AM/...TONIGHT AND BEYOND

TONIGHT...DEEPER MOISTURE/COLDER AIR/SFC LOW AND DPVA FROM 
PINWHEELING VORTICITY MAXIMA...ALL LIFT UP ACROSS THE NORTH WOODS 
TONIGHT TO BRING A PERIOD OF SNOW TO ALL LOCATIONS. NO SIGNIFICANT 
ACCUMULATIONS EXPECTED ATTM...BUT MAYBE UP TO 2 INCHES CAN FALL 
ACROSS BEST LOW LEVEL CONVERGENCE THAT LIES FROM MANISTEE TO 
DRUMMOND ISLAND. CLOUDS WITH MINIMAL THERMAL ADVECTIONS TO KEEP 
TEMPERATURES IN THE 20S.

SUNDAY...LINGERING LOW LEVEL CONVERGENCE AND DEEPER MOISTURE ACROSS 
THE NW CWA...WHILE A DEVELOPING NW FLOW WILL ACTUALLY SERVE TO WARM 
THE LOW LEVELS UP (H8 TO -8C...POTENTIAL ICE INTRODUCTION ISSUES 
LATER IN THE DAY?). WILL KEEP ONGOING IDEA OF LIKELY CHANCES FOR 
SNOW IN THE NW CWA...WHILE MORE SCATTERED ACTIVITY LIKELY DEVELOPS 
ACROSS THE SE HALF OF THE CWA...WHERE COLD 700MB POCKET OF AIR 
BRINGS ON A PERIOD OF STEEPER LOW LEVEL LAPSE RATES. 

SUNDAY NIGHT INTO MONDAY...UPPER LOW SHIFTS EASTWARD...WHILE A NRN 
STREAM SHORTWAVE DIVES ACROSS ONTARIO AND ACTUALLY SERVES TO SHARPEN 
UP THE LOW LEVEL TROUGHING THROUGH MONDAY MORNING. 1000-850MB WINDS 
WILL BE ON THE RISE (30KTS)...WHILE THE CYCLONIC CONVERGENCE IS 
RATHER IMPRESSIVE ATTM...TAPPING INTO LAKE SUPERIOR QUITE WELL. H8 
TEMPS ARE RIGHT AT -8C WHILE THE DEEPEST MOISTURE AND CONVERGENCE 
ARE HERE. AS THE BETTER THERMAL PROFILES FOR LES ARRIVE LATER 
MONDAY...WE UNDERGO SUBSTANTIAL DRYING. FOR THE SNOW LOVERS...WE 
JUST CANNOT SEEM TO GET OUR SNOW ACT GOING. LES WILL BE LIKELY 
DURING THIS TIME PERIOD. 

LATER PERIODS...NO CHANGES. SMD 

&&

.MARINE.../ISSUED AT 232 AM/

STRONG EASTERLY FLOW AHEAD OF NORTHWARD ADVANCING OCCLUDED FRONT 
WILL CONTINUE TO BRING GALES TO MUCH OF THE LAKE HURON NEARSHORE 
WATERS...FAR NRN LAKE MICHIGAN AND WHITEFISH BAY NEARSHORES AND 
SAINT MARY'S RIVER SYSTEM. THIS LIKELY TO ONLY PERSIST THROUGH 5AM 
OR SO...AS A MUCH LIGHTER WIND FIELD DEVELOPS OUT OF THE SOUTH. 
THUS...PLAN ON DROPPING GALE WARNINGS AT 5AM ISSUANCE. WILL NEED 
SOME SMALL CRAFT ADVISORIES FOR A TIME THIS MORNING DUE TO WAVE 
ACTION AND DECAYING GUSTINESS. A LIGHT SOUTHERLY FLOW IS EXPECTED TO 
SLOWLY TURN WESTERLY SUNDAY NIGHT. WINDS INCREASE OUT OF THE 
NORTHWEST MONDAY...AS A STRONG COLD FRONT BLASTS THROUGH THE GREAT 
LAKES. NEW HEADLINES (SMALL CRAFTS) ARE LIKELY. SMD 

&&

.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.

&&

$$