934
FXUS63 KAPX 091247
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
747 AM EST TUE FEB 9 2010
SYNOPSIS
/ISSUED AT 400 AM/
LOW PRESSURE WILL MOVE ACROSS THE OHIO VALLEY TONIGHT. THIS WILL
SPREAD SNOW ACROSS LOWER MICHIGAN BY LATE TODAY...WITH HEAVIER
ACCUMULATIONS THROUGH WEDNESDAY MORNING EXPECTED ACROSS CENTRAL
AND SOUTHERN LOWER MICHIGAN. LIGHT SNOW SHOWERS WILL PERSIST
ACROSS THE LAKE SUPERIOR AND LAKE MICHIGAN SNOWBELTS IN THE WAKE
OF THIS SYSTEM THROUGH THURSDAY. HIGH PRESSURE WILL BRING A
STRETCH OF PRECIPITATION FREE WEATHER TO THE AREA FRIDAY INTO THE
FIRST HALF OF THE WEEKEND.
AJS
SHORT TERM.../ISSUED AT 747 AM/
TODAY
740 AM: SENT AN UPDATE TO ACCT FOR A REPORT OF -SN FROM OUR
CLIMATE OBSERVER IN APN AND FLURRIES AT OSC. FCST DATABASE/WEBPAGE/
ZFP/APN TAF ALL UPDATED/POSTED.
JH/AJS
THE REST AS FOLLOWS FROM 4 AM...
ATTENTION THIS MORNING REMAINS FOCUSED ON UPPER LOW CURRENTLY OVER
WRN IA...AND THE IMPACT IT MAY HAVE ON THE REGION/S WEATHER TODAY
AND TONIGHT. EARLY MORNING SURFACE MAP SHOWED AN EXTENSIVE INVERTED
TROUGH ASSOCIATED WITH THE UPPER LOW EXTENDING FROM THE LOWER MS
VALLEY TO THE WRN GREAT LAKES. AS THE UPPER LOW CHURNS EWD ACROSS
THE LOWER GREAT LAKES TODAY IT WILL PHASE WITH ANOTHER PIECE OF
ENERGY CURRENTLY EXITING OKLAHOMA. THE ENHANCED DYNAMICS WILL
RESULT IN CYCLOGENESIS...AS A DEEPENING SURFACE LOW LIFTS NE TO
CENTRAL OH BY THIS EVENING. 00Z MODELS AGREE ON THIS SCENARIO...
AND HAVE ALSO SHOWN EXCELLENT RUN TO RUN CONSISTENCY.
FORCING FOR ASCENT AND MOISTURE WILL INCREASE TODAY...WITH BOTH
850-700 MB WAA AND MID-UPPER LEVEL QG SUPPORT EXPANDING INTO THE
REGION -- THOUGH THE BEST LIFT WILL REMAIN ACROSS SRN LOWER MI
TODAY AND TONIGHT. GFS IS A BIT MORE BULLISH THAN THE NAM IN
SPREADING MAINLY LIGHT SNOW INTO NRN LOWER MI TODAY. CONSIDERING
IMPACT OF DRY E/NE FLOW...WILL ADOPT A NAM/GFS COMPROMISE FOR
TIMING...WITH LIGHT SNOW REACHING TVC-GRAYLING-STANDISH CORRIDOR
BY 18Z...AND THE PETOSKEY-ALPENA CORRIDOR BY LATE AFTERNOON.
STEADIEST SNOW TODAY WILL REMAIN SOUTH OF A TVC-HARRISVILLE LINE...
WHERE AN INCH OR SO MAY FALL BY LATE AFTERNOON. OTHERWISE...CLOUDS
WILL THICKEN TODAY WITH HIGHS REACHING THE 20S.
SMITH
LONG TERM.../ISSUED AT 400 AM/
TONIGHT AND BEYOND
TONIGHT...SURFACE LOW OVER OH WILL DRIFT ENE AND WEAKEN...AS A
STRONGER LOW DEVELOPS OVER THE MID ATLANTIC REGION. AS
MENTIONED...FORCING WILL REMAIN STRONGEST ACROSS SRN LOWER MI --
AND THIS IS WHERE THE HEAVIEST SNOW WILL OCCUR. IN OUR NECK OF THE
WOODS...ASCENT WILL REMAIN RESPECTABLE HOWEVER AS UPPER TROUGH
AXIS SWINGS EWD...AND MODEST EAST FLOW ISENTROPIC ASCENT PERSISTS.
THOUGH OVERALL QPF WON/T BE GREAT...POTENTIAL EXISTS FOR HIGH
SNOW:LIQUID RATIOS. THIS IS SUPPORTED BY MODEL SOUNDING VERTICAL
PROFILES OF MAX OMEGA...WHICH DESCEND NICELY INTO THE DGZ BETWEEN
ROUGHLY 00-09Z. WITHOUT ANY APPRECIABLE RIMING POTENTIAL BELOW THE
DGZ -- GIVEN COLD ENVIRONMENT -- RATIOS AROUND 20:1 APPEAR LIKELY.
WITH QPF OVER SRN AREAS APPROACHING 0.30 INCH...EXPECT A GENERAL
3-5 INCH SNOWFALL ACROSS THESE AREAS THIS AFTERNOON AND TONIGHT.
THIS IS FURTHER SUPPORTED BY 700-750 MB MIXING RATIOS BETWEEN 1.5
AND 2.0 G/KG.
ANOTHER POTENTIAL COMPLICATING FACTOR WILL BE LAKE ENHANCEMENT
OFF LAKE HURON THIS EVENING WITH NE WINDS...AND LAKE ENHANCEMENT OFF
LAKE MICHIGAN LATE TONIGHT AS WINDS BACK TO N. THOUGH MODEL
SOUNDINGS NOT STRONGLY SUPPORTIVE OF THIS...POTENTIAL WILL NEED TO
BE MONITORED.
TOTAL SNOWFALL FOR TODAY AND TONIGHT WILL BE MARGINAL FOR AN
ADVISORY. HOWEVER...CONSIDERING BRISK NE WINDS...THE BLOWING AND
DRIFTING POTENTIAL...AND THE ORIENTATION OF EXISTING HEADLINES S/W
OF REGION...A WINTER WEATHER ADVISORY IS WARRANTED FOR THE SRN TWO
ROWS OF COUNTIES FOR LATE THIS AFTERNOON AND TONIGHT -- INCLUDING
THE COMMUNITIES OF MANISTEE...HOUGHTON LAKE...GLADWIN...AND
TAWAS.
WEDNESDAY...BRISK N/NW WINDS WILL OVERSPREAD NRN MI IN THE WAKE OF
STORM SYSTEM. SCATTERED TO NUMEROUS SNOW SHOWERS ARE EXPECTED...
WITH PERSISTENT CYCLONIC FLOW AND A POCKET WITH WEAK MID LEVEL
FORCING. LAKE CONTRIBUTIONS LOOK INCREASINGLY WEAK...WITH 850 MB
TEMPS AROUND -10C AND INVERSIONS BELOW 4 KFT. AN INCH OR TWO WILL
BE POSSIBLE IN THE NNW FLOW AREAS OF NW LOWER.
THURSDAY AND FRIDAY...RATHER UNEVENTFUL WEATHER EXPECTED. COOL
N/NW BREEZES WILL PERSIST. OVER-WATER INSTABILITY WILL REMAIN
LIMITED /WITH 850 MB TEMPS BETWEEN -10 AND -12C/. LOW LEVEL FLOW
WILL REMAIN WEAKLY CYCLONIC...AS A COUPLE MID LEVEL IMPULSES PUSH
E/SE ACROSS THE NRN GREAT LAKES. WILL OPT FOR MOSTLY CLOUDY SKIES
WITH A FEW FLURRIES OR LIGHT SNOW SHOWERS. HIGHS BOTH DAYS WILL
REACH INTO THE 20S.
NO CHANGES MADE TO FORECAST BEYOND FRIDAY.
SMITH
MARINE
/ISSUED AT 400 AM/
SMALL CRAFT ADVISORIES CONTINUE AS BRISK N/NE WINDS DEVELOP TODAY
AND TONIGHT NORTH OF OHIO VALLEY STORM SYSTEM.
SMITH
AVIATION.../ISSUED AT 642 AM/
VALID FOR 12Z TAFS
MVFR CEILINGS WILL IMPACT ALL TAF SITES BY THIS AFTERNOON...IN
RESPONSE TO LAKE INSTABILITY...AND INCREASING LIFT/MOISTURE
ASSOCIATED WITH SURFACE LOW MOVING INTO THE OHIO VALLEY BY
TONIGHT. SNOW WILL IMPACT TVC/PLN/APN BY LATE AFTERNOON AND
EVENING WITH MVFR AND POSSIBLY IFR VSBYS EXPECTED.
APX WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR MIZ031>036-041-042.
LM...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
WEDNESDAY FOR LMZ344>346.
LH...NONE.
LS...NONE.
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