FXUS63 KAPX 250503
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1203 AM EST FRI DEC 25 2009
.SYNOPSIS.../ISSUED AT 427 PM/
A STORM SYSTEM OVER TEXAS...WILL SLOWLY LIFT NORTH INTO THE CENTRAL
PLAINS TONIGHT...BEFORE MOVING INTO IOWA FRIDAY. THIS SYSTEM WILL
SLOWLY ROTATE INTO THE GREAT LAKES BY SUNDAY.
THIS SYSTEM WILL GENERATE A LIGHT WINTRY MIX OVER THE GRAND TRAVERSE
BAY REGION THIS EVENING....BEFORE OVERSPREADING THE REST OF NORTHERN
MICHIGAN TONIGHT. WARMER AIR WILL RIDE INTO STATE FRIDAY...GENERATING
MAINLY RAIN OVER NORTHERN MICHIGAN.
SNOW IS POSSIBLE FRIDAY NIGHT INTO EARLY NEXT WORK WEEK...AS THE
LAKE EFFECT MACHINE TRIES TO GET STARTED AGAIN.
SWR
&&
.SHORT TERM.../ISSUED AT 1030 PM/...REST OF TONIGHT
WHILE NOT A "SIGNIFICANT" EVENT (IN TERMS OF PRECIPITATION
QUANTITY)...EASILY ONE OF THE MORE CHALLENGING PRECIP TYPE FORECASTS
IN RECENT MEMORY. EXPANSIVE...BUT RATHER LIGHT...INITIAL WAA WING OF
PRECIPITATION HAS NOW ADVANCED TO THE MIGHTY MAC...DESPITE IMPRESSIVE
DEWPOINT DEPRESSION NOTED ON EARLIER SOUNDINGS. PRECIPITATION TYPE
EVEN MORE CHALLENGING THAN PLACEMENT...WITH FREEZING RAIN AND SLEET
MIXTURE BEING REPORTED AT MOST LOCATIONS...BUT A QUICK GLANCE OUT
THE WINDOW HERE REVEALS ALL SNOW (GUESS...DESPITE THE WEAK
INTENSITY...EVAPORATIONAL COOLING WINNING OUT). HOWEVER...
INTERESTINGLY...POINTS TO THE NORTH IN THE STRAITS REGION HAVE
REPORTED LIGHT FREEZING RAIN FOR THE PAST COUPLE HOURS...WITH VERY
SLICK CONDITIONS AND EVEN SOME ROAD CLOSURES. NOW...AREAS EAST OF
I-75 AND CHIPPEWA COUNTY IN EASTERN UPPER HAVE REPORTED VERY LITTLE
PRECIPITATION WITH LIGHTER MID LEVEL ECHOS SIMPLY NOT OVERCOMING DRY
WEDGE. REGIONAL RADARS SHOW BACK EDGE OF MOST WIDESPREAD ACTIVITY
ALREADY ADVANCING INTO OUR SOUTHERN ZONES...WITH SOME MORE SPOTTY
ACTIVITY DEVELOPING JUST SOUTH OF OUR BORDER. TEMPERATURES
STRUGGLING BETWEEN WEAK LOW LEVEL WAA...LATENT HEAT RELEASE...AND
EVAPORATIONAL COOLING...WITH READINGS JUST STARTING TO INCH THEIR
WAY UP. UPSHOT TO ALL OF THIS...WILL EXPAND WINTER WEATHER HEADLINES
THROUGH THE STRAITS REGION (CHEBOYGAN...EMMET...AND MACKINAC
COUNTIES) AND EXTEND IT THROUGH 2AM (MORE TO ACCOUNT FOR RESIDUE
EFFECTS THAN MUCH ADDITIONAL PRECIPITATION). PRECIPITATION COVERAGE
SHOULD CONTINUE TO SCATTER OUT AS THE NIGHT PROGRESSES...WITH SOME
AREAS CHANGING TO PLAIN RAIN AS TEMPERATURES CONTINUE TO SLOWLY
WARM.
MSB
&&
.LONG TERM.../ISSUED AT 427 PM/...FRIDAY AND BEYOND
MAIN CONCERN FOR THE FORECAST IS THE LOW AND THE RA/FZRA/SN CHANCES.
CHRISTMAS...THERMAL PROFILES ARE GOING MORE TOWARD RAIN BY 15Z. WILL
ALLOW FOR SOME SNOW INLAND IN THE MORNING, BUT AS BOTH THE GFS AND
THE NAM POINT TO IS THE SIZABLE WARM NOSE THAT WILL MELT MOST IF
NOT ALL OF THE SNOW. WARM ADVECTION AT THE SFC WILL THEN WORK ITS
WAY INTO THE MAIN AREAS SO THAT EVEN IN E UPPER THAT IT SHOULD BE
ALL RAIN.
CHRISTMAS NIGHT...AFTER 00Z, THE SFC LOW PUSHES THE COLD AIR BACK
INTO THE REGION AND CHANGES THE P-TYPE BACK TO SNOW. CONSIDERING
THAT IT IS OVER 36 HOURS AWAY, WON'T GET TOO CUTE WITH TIMING, BUT
WILL PROBABLY SEE A GRADUAL CHANGE OVER BETWEEN 00Z AND 03Z. MID
LEVEL DRYING PUSHES IN, BUT THE COLDER AIR AT 850 MB ALLOWS THE
MOISTURE STILL AROUND 70% TO 80% AT THE -10C LEVEL FOR PREDOMINATELY
SNOW. ALTHOUGH IT THE SNOW SHOWERS WILL BECOME MORE SCATTERED WITH
TIME.
SATURDAY...MORE COLD AIR, MORE MOISTURE AND THE SFC LOW IS STILL TO
THE SW OF THE REGION. SO WILL EXPECT THAT THERE WILL BE MORE SNOW
SHOWERS SCATTERED AROUND THE FORECAST. WINDS CONTINUE OUT OF THE SE.
SO WILL HAVE TO BE ON THE WATCH FOR LES FROM THE SE. THE MAIN
CHANCES FOR SNOW WILL BE IN NW LOWER AND E UPPER AS THE LFQ OF THE
500 MB JET MOVES OVER THE FORECAST AREA.
SATURDAY NIGHT...THE UPWARD DYNAMIC FORCING CONTINUES TO FOCUS NEAR
N LOWER. IT LOOKS LIKE WITH THE TROUGHS, THAT THE MAIN FOCUS WILL
PUT IT IN MORE OR LESS ON A LINE FROM MBL TO PZQ.
SUNDAY...WILL SEE HOW THIS PANS OUT, BUT THE LOW CONTINUES TO MOVE
OVER N LOWER WITH THE CORE BY 00Z, GETTING TO EAST SIDE OF THE
STATE. THIS WILL ALLOW LES TO BEGIN TO DEVELOP BY THE AFTERNOON.
OVERNIGHT, LES LOOKS TO BE THE BEST BET AS THE 850 MB TEMPERATURES
ARE AROUND -10C WITH NW OR NNW WINDS.
EXTENDED (MONDAY THROUGH THURSDAY)...MAIN CONCERN FOR THE EXTENDED
PORTION OF THE FORECAST PACKAGE WILL BE THE SPEED OF WHICH THE
VERTICALLY STACKED LOW MOVES OUT OF THE FORECAST AREA. SUNDAY, AS
THE LOW FILLS, IT BEGINS TO MOVE OUT OVER N LOWER AS THE NEXT PIECE
OF 500 MB ENERGY KICKS THE SYSTEM EAST AS IT FILLS AND OPENS. SO
SNOW SHOWERS AS THE SYSTEM MOVES OUT WITH LES ASSOCIATED DEPENDING
ON THE WIND DIRECTIONS. MONDAY, A COLD FRONT MOVES INTO THE REGION
AND TO KICK OFF SOME MORE SNOW SHOWERS AND PROBABLY LAKE SNOW POST
FRONTAL. TUESDAY, 500 MB HEIGHTS BUILD WITH THE SFC HIGH BUILDING
INTO THE REGION. SYNOPTIC MOISTURE SHOULD WANE, SO WILL THINK THAT
THERE COULD BE SOME CLEARING THROUGH THE DAY AND INTO THE NIGHT.
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 IN E UPPER WITH THE FRONT. THURSDAY, A NEW COLD FRONT
WILL MOVE THROUGH THE REGION AND LOOKS LIKE IT WILL KICK OFF SNOW AS
IT MOVES THROUGH.
JSL
&&
.MARINE.../ISSUED AT 427 PM/
EAST/SOUTHEAST WINDS ANTICIPATED TO INCREASE TONIGHT...REACHING GALE
FORCE ACROSS THE LAKE MICHIGAN/HURON NEARSHORE ZONES...LATER TONIGHT
INTO CHRISTMAS DAY. CURRENT GALE WARNINGS/SMALL CRAFT ADVISORIES
WILL CONTINUE.
ADAM
&&
.AVIATION.../ISSUED AT 1202 AM/...VALID FOR 06Z TAFS
CLOUDS REMAIN A FORMIDABLE CHALLENGE ACROSS ALL TAF SITES
THROUGH THE NIGHT AS INITIAL SLUG OF WAA PRECIPITATION PULLS NORTH OF
THE REGION. MVFR TO HIGH IFR CIGS EXPECTED AT BOTH KPLN AND KAPN
WHERE LOW LEVEL MOISTURE (POSSIBLE SOME LAKE HURON INFLUENCE)
REMAINS. TOUGHER CALL AT KTVC AS DOWNSLOPE WINDS HELP MIX OUT LOW
OVERCAST THROUGH THE EARLY MORNING HOURS. NEXT ROUND OF HEAVIER RAIN
SHOULD PIVOT SOUTH TO NORTH FAIRLY RAPIDLY FRIDAY MORNING.
THIS...COMBINED WITH WARM AIR ADVANCING OVER DEEP NORTHERN MICHIGAN
SNOWPACK SHOULD LEAD TO WIDESPREAD IFR STRATUS FIELD. WILL ALSO SEE
SOME VIS RESTRICTIONS AS LIGHT FOG ADVECTS OFF THE SNOWPACK AND
DURING HEAVIER RAIN. THESE CONDITIONS SHOULD CONTINUE THROUGH FRIDAY
EVENING...WITH PERHAPS RAIN BECOMING MIXED WITH OR CHANGING TO SNOW
LATE. GUST EAST TO SOUTHEAST WINDS WILL PREVAIL THROUGH THIS TAF
PERIOD.
MSB
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 2 AM EST EARLY THIS MORNING FOR
MIZ015>017-019>022-025>028-031>034-041.
LM...GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LMZ323-341-342-
344>346.
LH...GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LHZ345>349.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR LSZ321-
322.
&&
$$
