FXUS63 KAPX 011637
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1137 AM EST TUE DEC 1 2009
.SYNOPSIS.../ISSUED AT 407 AM/
LIGHT LAKE EFFECT RAIN AND SNOW SHOWERS BEHIND A DEPARTING ALBERTA
CLIPPER WILL COME TO AN END TODAY. A NEW AREA OF LOW PRESSURE LIFTS
ACROSS THE NORTHERN GREAT LAKES TONIGHT....AND WILL RESULT IN
POCKETS OF DRIZZLE ACROSS EASTERN UPPER MICHIGAN LATE TONIGHT AND
INTO WEDNESDAY.
THE WEATHER WILL TURN MORE UNSETTLED THURSDAY...AS A STRONG STORM
SYSTEM WILL LIFT FROM KENTUCKY INTO NEW ENGLAND. COLDER AIR POURS
INTO THE REGION AND LAKE EFFECT SNOWS ARE EXPECTED TO DEVELOP. MUCH
OF THE NORTH WOODS CAN EXPECT PERIODS OF SNOW THROUGH THE WORK
WEEK...AND POSSIBLY RIGHT ON THROUGH THE WEEKEND. MOST OF THE SNOW
WILL TARGET NORTHWEST LOWER AND EASTERN UPPER.
SMD
&&
.SHORT TERM.../ISSUED AT 1138 AM/...THIS AFTERNOON
WEST WINDS WILL BACK TO THE SOUTH OVER THE AFTERNOON AND PUSH THE
CLOUDS TO THE NORTH. THE ONLY PLACE THAT MAY NOT SEE MUCH SUNSHINE
TODAY WILL BE E UPPER AS THE WARM FRONT THAT IS MOVING INTO THE
FORECAST AREA WILL REMAIN OVER E UPPER. THE GRADIENT SLACKENS
DURING THE AFTERNOON, SO HAVE ADJUSTED THE WINDS DOWN FOR FOR NOW
AND TONIGHT.
JSL
&&
.LONG TERM.../ISSUED AT 407 AM/...TONIGHT AND BEYOND
TONIGHT...INITIAL ROUND OF MID LEVEL HEIGHT FALLS ACROSS THE
NORTHERN PLAINS INDUCES WEAK SURFACE LOW THAT MOVES INTO THE
NORTHERN LAKES BY MORNING. DESPITE INCREASING LOW LEVEL MOISTURE
BEHIND NORTHWARD BOWING WARM FRONT AND OUT AHEAD OF APPROACHING
WEAKENING COOL FRONT...DEEP LAYER MOISTURE AND DYNAMICS REMAINS
DECIDEDLY LACKING...ARGUING FOR POTENTIAL DRIZZLE FORMATION LATER
TONIGHT. UTILIZING GFS/NAM-WRF BUFR SOUNDINGS SHOWS NEAR SURFACE
LAYER SLOWLY MOISTENING...ESPECIALLY ACROSS EASTERN UPPER. FARTHER
SOUTH...MOISTURE PROFILES REMAIN VERY SHALLOW...WITH EVEN SOME
EVIDENCE OF INVERTED-V PROFILE RIGHT AT THE SURFACE. WHILE SOUNDINGS
NOT ENTIRELY SUPPORTIVE OF INHERITED DRIZZLE MENTION...HARD TO
JUSTIFY COMPLETE REMOVAL...ESPECIALLY AS AFOREMENTIONED COOL FRONT
PROVIDES SOME LOW LEVEL FOCUS LATE. RATHER MILD OVERNIGHT GIVEN
MAINTENANCE OF SOUTHWEST WINDS...AND EXPECT MOST AREAS OF NORTHERN
LOWER REMAINING ABOVE FREEZING. RATHER BORDERLINE ACROSS EASTERN
UPPER...WITH LOWS DROPPING INTO THE LOWER 30S...JUSTIFYING
MAINTENANCE OF INHERITED FREEZING DRIZZLE POTENTIAL THERE.
WEDNESDAY AND WEDNESDAY NIGHT...AFTER SOME PATCHY DRIZZLE EARLY
WEDNESDAY...MOST OF THE DAY SHOULD BE RATHER BENIGN. THEREAFTER
...ALL EYES TURN TOWARDS APPROACH OF SOUTHERN STREAM WAVE...AND
POSSIBLE INTERACTION WITH NORTHERN STREAM SHORTWAVE DIGGING INTO THE
WESTERN LAKES. STILL CONSIDERABLE UNCERTAINTY WITH HOW THIS ALL
UNFOLDS...WITH THE NAM-WRF SUGGESTING MORE INTERACTION...AND HENCE A
FARTHER NORTHWEST TRACK OF DEEPENING SURFACE LOW INTO WESTERN LAKE
ERIE BY LATE WEDNESDAY EVENING. THIS ITERATION HAS SOME SUPPORT BY
LAST SEVERAL RUNS OF UKMET GUIDANCE. STILL...THIS REPRESENTS A
SIGNIFICANT EAST TREND FROM EARLIER RUNS...WITH THE NAM-WRF STARTING
TO TREND TOWARD THE AWFULLY CONSISTENT ECMWF SOLUTION...FEATURING A
SURFACE LOW TRACK JUST WEST OF THE APPALACHIANS. WHILE NORTHWEST
TREND WITH EJECTING SOUTHWEST CONUS SYSTEMS IS WELL DOCUMENTED OVER
THE PAST SEVERAL YEARS...HARD TO IGNORE RATHER SYSTEMATIC EAST TREND
SEEN IN NON-ECMWF GUIDANCES TOWARDS ITS SOLUTION. IN ADDITION...FEEL
EXPECTED GULF COAST CONVECTIVE OUTBREAK AS INITIAL WAVE APPROACHES
MAY ALLOW AN EAST ADJUSTMENT TO SURFACE CYCLOGENESIS AT ITS
INITIALIZATION. WHILE CONFIDENCE LEVEL REMAINS MARGINAL AT BEST...
HAVE TRENDED WEDNESDAY NIGHTS GRIDS IN THIS DIRECTION...RELEGATING
HIGH CHANCE MENTION TO FAR SOUTHEAST COUNTIES ONLY (INITIAL
RAIN/SNOW MIXTURE BEFORE TRANSITIONING TO ALL SNOW). IN ADDITION...
EVEN IF FARTHER NORTHWEST TREND IS REALIZED... AFOREMENTIONED
SOUTHERN CONVECTIVE OUTBREAK MAY VERY WELL PREVENT A SIGNIFICANT
BACKSIDE DEFORMATION/TROWEL PRECIPITATION SHIELD FROM FORMING AS
MOISTURE DISRUPTION OCCURS. STILL...LOTS OF THINGS YET TO BE
DECIDED...AND WOULD EXPECT SOME FUTURE MODIFICATIONS TO HOW
EVERYTHING EVOLVES...ESPECIALLY WHEN SOUTHERN WAVE IS BETTER SAMPLED
AS IT ENTERS THE UPPER AIR NETWORK. OTHERWISE...BEGINNINGS OF
SIGNIFICANT CAA SHOULD TAKE PLACE LATE WEDNESDAY NIGHT AS NORTH FLOW
INCREASES. INITIAL LACK OF SYNOPTIC MOISTURE AND LOW INVERSION
HEIGHTS SHOULD KEEP LES DEVELOPMENT MINIMAL UNTIL THURSDAY.
THURSDAY AND BEYOND...QUESTION CONTINUE TO ABOUND WITH WHAT COULD
POTENTIALLY BE OUR FIRST SIGNIFICANT LAKE EFFECT EVENT THURSDAY
THROUGH THE UPCOMING WEEKEND. MAIN QUESTION INVOLVES BOUNDARY LAYER
WIND DIRECTION AS LAKE INDUCED TROUGHING STRENGTHENS AND WAVES
ROTATE WITHING DEEP GREAT LAKES TROUGH AXIS. WILL SAY WITH EXPECTED
PLACEMENT OF PARENT MID LEVEL GYRE TO OUR NORTHWEST AND STRENGTH OF
AGGREGATE LAKE TROUGHING...STARTING TO HAVE A SUSPICION THAT AFTER
INITIAL WEST TO NORTHWEST FLOW WIND FIELD THURSDAY...THIS MAY BE A
PROLONGED WEST SOUTHWEST TO SOUTHWEST EVENT. WILL NOT GET BOGGED
DOWN BY THESE MESOSCALE DETAILS JUST YET AND SIMPLY RUN WITH INHERITED
GRIDS THROUGH THIS PERIOD...FEATURING BROADBRUSHED LIKELY POPS
DOWNWIND OF LAKE SUPERIOR AND MICHIGAN. FIRST SUSTAINED COLD SNAP OF
THE SEASON WILL ALSO ALLOW TEMPERATURES TO AT LEAST APPROACH EARLY
DECEMBER NORMALS...WITH HIGHS IN THE UPPER 20S AND LOWER 30S AND
LOWS IN THE TEENS AND 20S.
MSB
&&
.MARINE.../ISSUED AT 1138 AM/
WINDS SHOULD STEADILY DECREASE WHILE THEY BACK THIS AFTERNOON.
SOUTHWEST WINDS WILL BE ON THE INCREASE ONCE AGAIN
TONIGHT...ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN...BUT IT
APPEARS AT THIS TIME BOTH WIND AND WAVES WILL STAY BELOW ADVISORY
CRITERIA. NEXT SET OF HEADLINES POSSIBLE LATER WEDNESDAY NIGHT
INTO THURSDAY...POSSIBLE GALES...AS STRONG LOW PRESSURE PIVOTS
EAST OF MICHIGAN.
MSB/JSL
&&
.AVIATION.../ISSUED AT 616 AM/...VALID FOR 12Z TAFS
VFR BROKEN/OVERCAST CIGS EXPECTED THROUGH THIS EVENING AT ALL TAF
SITES AS LINGERING LAKE PROCESSES INTERACT WITH DEVELOPING WAA
REGIME. INCREASING BOUNDARY LAYER MOISTURE BEHIND DEPARTING WARM
FRONT AND AHEAD OF APPROACHING COOL FRONT...INTERACTING WITH
TYPICAL NOCTURNAL COOLING...COULD POSSIBLY KICK OFF WIDESPREAD
MVFR STRATUS DECK LATER TONIGHT. WILL INDICATE AS SUCH AT ALL
SITES...BUT OVERALL CONFIDENCE ON EXACT TIMING...CIG LEVEL...AND
COVERAGE RATHER LOW AT THIS POINT.
MSB
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
LH...NONE.
LS...NONE.
&&
$$
