FXUS63 KAPX 242128
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
427 PM EST THU DEC 24 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 427 PM/...TONIGHT
COMPLEX WEATHER PATTERN CONTINUES TO UNFOLD ACROSS THE PLAINS AND
WESTERN GREAT LAKES. ON THE BIG PICTURE...HIGH AMPLITUDE TROUGH
SITTING ACROSS THE CENTRAL CONUS WITH ONE STRONG SHORT WAVE AND
DEEPENING SFC LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY. SECOND
POTENT WAVE DROPPING THROUGH NRN ROCKIES INTO THE BACKSIDE OF THE
UPPER TROUGH AND EXPECTED TO PHASE WITH THE SRN WAVE OVER THE NEXT
24 TO 36 HOURS. INVERTED SFC TROUGH AXIS STRETCHES FROM THE LOW OVER
ARKANSAS ALL THE WAY INTO THE UPPER MIDWEST WITH PERIODIC SURGES OF
WARM ADVECTION FORCING/LIGHT PRECIP MAKING INROADS INTO THE CWA.
NEXT PUSH OF WARM ADVECTION FORCING/LIGHT PRECIP IN THE PROCESS OF
SPREADING NORTH THROUGH SRN AND CENTRAL LOWER MICHIGAN LATE THIS
AFTERNOON AND WILL BE IMPACTING THE AREA THIS EVENING. BUT BY AND
LARGE...PRECIP HAS BEEN LIGHT DESPITE THE RADAR...THANKS TO A
CONTINUING DRY SE FLOW INTO THE REGION.
TONIGHT...MAIN FORECAST GOAL CONTINUES TO BE HANDLING ANY NEEDED
SHORT TERM HEADLINES WITHOUT BACKING LATER SHIFTS INTO A CORNER. AS
MENTIONED ABOVE...NEXT BATCH OF WARM ADVECTION PRECIP IS ON THE WAY
FOR THIS EVENING...WORKING UP THROUGH CENTRAL AND SRN LOWER MICHIGAN
WITH THE "HEAVIEST" OF THE PRECIP RUNNING UP THE LAKE MICHIGAN
SHORELINE IN THE GRR CWA. BUT PER REGIONAL RADAR PLOT...STRONGEST
FORCING AND BULK OF PRECIP IS SETTING UP TO FOCUS WEST OF HERE
(WISCONSIN AREA) WITH JUST A "WING" OF PRECIP SLIPPING UP THROUGH
THE CWA THIS EVENING. SO OVERALL...A RELATIVELY LOWER END QPF EVENT
ON TAP.
NOW AS FOR PRECIP TYPE...ELEVATED ABOVE FREEZING LAYER FORECAST TO
OVERSPREAD THE CWA TONIGHT...WITH BOTH THE NAM/GFS SOLUTIONS
DRAGGING +3C TO +6C AIR INTO NRN MICHIGAN BY CHRISTMAS MORNING. SO
OTHER THAN PERHAPS A LITTLE SNOW IN THE EARLY GOING THIS
EVENING...SNOW IS PRETTY MUCH OUT OF THE FORECAST TONIGHT (AND
THROUGH MUCH OF CHRISTMAS DAY). SO NOW IT/S A MATTER OF THE MELTING
LAYER DEPTH/WET BULBING EFFECTS AND SFC TEMPS. THIS EVENING...WITH
MOST AREAS STILL BELOW FREEZING...LOOKS LIKE A PERIOD OF LIGHT
SLEET/FREEZING RAIN WITH THE HIGHEST QPF IMPACTING THE SW COUNTIES
WHERE THE CURRENT ADVISORY IS ALREADY UP. AGAIN...NOT A PARTICULARLY
HIGH QPF EVENT...BUT PROBABLY ENOUGH TO JUSTIFY STRETCHING THE
CURRENT ADVISORY THROUGH THE EVENING HOURS. FOR THE EASTERN
COUNTIES...DON/T THINK COVERAGE AND QPF AMOUNTS WILL BE ENOUGH TO
WARRANT A HEADLINE.
OVERNIGHT...THINK PRECIP COVERAGE WILL THIN AGAIN AS MAIN BULK OF
FORCING FOCUSES INTO AREAS WEST OF HERE. MEANWHILE...WITH CONTINUING
WARM ADVECTION...SFC TEMPS WILL PROBABLY GRADUALLY RISE OVERNIGHT...
POSSIBLY TO ABOVE FREEZING FOR MOST AREAS AND BRING AN END TO ANY
FREEZING PRECIP THREATS.
ADAM
&&
.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 115 PM/...VALID FOR 18Z TAFS
MVFR CIGS AND MAINLY VFR VSBYS WILL CONTINUE OVER NRN MI TAF
SITES THIS AFTN AND EARLY EVENING...AS HIGH PRESSURE OVER THE ERN
LAKES MOVES INTO QUEBEC. MVFR CIGS AND VSBYS EXPECTED TONIGHT AS
WINTRY MIX PCPN OVERSPREADS THE REGION...AS A PLAINS STORM SYSTEM
LIFTS NORTH TWD THE UPPER MIDWEST. CIGS/VSBYS EXPECTED TO DIMINISH
TO IFR FRIDAY MORNING AND LINGER INTO THE AFTN...AS WARMER AIR
LIFTS NORTH INTO THE REGION IN ADVANCE OF APPROACHING PLAINS SYSTEM.
PCPN TYPE DIFFICULT THROUGH THE PD...AS WARMER AIR ALOFT MOVES OVER
NRN MI WHILE SFC REMAINS SLOW TO WARM DUE TO SNOW PACK. HOWEVER
FREEZING RAIN...RAIN AND SNOW ALL POSSIBLE OVER NRN MI TAF THRU THE
TAF PD.
SWR
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ020-025-026-
031-032.
LM...GALE WARNING UNTIL 5 PM EST FRIDAY FOR LMZ323-341-342-344>346.
LH...GALE WARNING UNTIL 5 PM EST FRIDAY FOR LHZ345>349.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR LSZ321-322.
&&
$$
