FXUS63 KMQT 010537 AAB
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1230 AM EST TUE DEC 1 2009
.SHORT TERM...TONIGHT AND TUESDAY
OVERALL A FAIRLY QUIET SHORT TERM FORECAST WITH SOME MINOR SNOW
ACCUMULATIONS EXPECTED THIS EVENING. WEAK SURFACE/MID LEVEL RIDGING
WILL GIVE WAY TO A CLIPPER SYSTEM PROGGED TO PASS OVER LAKE SUPERIOR
THIS EVENING. MODELS ARE IN GOOD AGREEMENT WITH THE DETAILS OF THIS
SYSTEM. DEEPER MOISTURE ARRIVES LATE THIS AFTERNOON ALONG WITH
MODEST SYNOPTIC LIFT PER 700-500MB QVECTOR DIV...ALLOWING SNOW TO
START IN THE WESTERN ZONES THIS AFTERNOON...MQT/IMT AROUND
SUNSET...ESC/ISQ/MUNISING AT 00Z AND ERY AROUND 02Z. NOT
ANTICIPATING A LONG DURATION SNOWFALL ONLY ON THE ORDER OF 2 TO 3
HOURS AS THIS SYSTEM IS FAIRLY PROGRESSIVE. EXPECT SUB ADVISORY
SNOWFALL WITH AMOUNTS IN THE 1 TO 2 INCH RANGE. WEAK LES ON THE
BACKSIDE OF THIS CLIPPER WILL ALLOW FOR ISOLD/SCATTERED SNOW SHOWERS
TO CONTINUE OVER NORTHWESTERLY SNOWBELTS...LITTLE TO NO ACCUMULATION
IS EXPECTED THOUGH. ON TUESDAY EXPECT ANY LINGERING -SHSN OVER THE
EAST TO BE DONE BY LATE TUESDAY MORNING AS WEAK SFC RIDGING SHIFTS
INTO THE UPPER GREAT LAKES FROM THE WEST. BY TUESDAY AFTERNOON SOME
LIGHT SNOW/RAIN COULD WORK INTO THE WEST AHEAD OF NEXT SYSTEM
EXPECTED TO CROSS LAKE SUPERIOR ON WEDNESDAY. OPTED TO TREND POPS
FURTHER WEST AS STRONGEST DYNAMICS REMAIN OVER MN FOR THE AFTERNOON.
&&
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
TUESDAY NIGHT INTO WEDNESDAY...PREFERRED THE 12Z GFS AND 12Z
CANADIAN REG GEM HANDLING OF THE NRN STREAM SHRTWV MOVING FROM NRN
MN INTO NRN ONTARIO COMPARED TO THE 12Z NAM WHICH TAKING THE SFC LOW
FARTHER SOUTH REMAINED AS AN OUTLIER ALSO COMPARED TO THE SREF MEAN.
MODERATE TO STRONG 700-300 QVECTOR CONV AND 285K-290K ISENTROPIC
ASCENT REMAINS MAINLY FROM NORTHERN LAKE SUPERIOR INTO NRN
ONTARIO...NORTH OF THE SFC-850 MB LOW PATH. OTHERWISE...THE DRY SLOT
TO MOVE ACROSS THE AREA WED MORNING FOLLOWED BY CAA DROPPING 850 MB
TEMPS FROM AROUND -8C AT 12Z/WED TO -12C BY 00Z/THU. SO...SCT LAKE
EFFECT SNOW SHOWERS WILL BECOME MORE NMRS DURING THE AFTERNOON OVER
THE WEST...ESPECIALLY AFTER WINDS VEER MORE NRLY.
WED NIGHT INTO THU...EVEN THOUGH THE AREA OF SYNOPTIC PCPN
ASSOCIATED WITH THE SRN STREAM SHRTWV AND SFC LOW MOVING INTO THE OH
VALLEY REMAIN SE OF UPPER MI...PER GLOBAL MODELS...THE MID LEVEL LOW
MOVING INTO THE UPPER MS VALLEY AND THE DEEPENING LOW TO THE EAST
SHOULD RESULT IN A PERIOD OF NRLY WINDS. THIS WILL BRING SOME LES
INTO MOST OF NRN UPPER MI. HOWEVER...THE LACK OF DEEPER MOISTURE AND
INVERSION HEIGHTS ONLY NEAR 5K WILL LIMIT LES INTENSITY.
THU NIGHT INTO FRI...EXPECT THE PERIOD OF HEAVIER LAKE EFFECT SNOW
AS THE MID LEVEL LOW MOVES INTO THE WRN GREAT LAKES. UNCERTAINTY
WITH THE POSITION OF THE MID LEVEL LOW...WITH THE GFS/CANADIAN MORE
TO THE SW THAN THE ECMWF...LEADS TO UNCERTAINTY WITH THE POSITION OF
THE SFC TROUGH AND LOW LEVEL WIND FIELDS. FOR NOW...EXPECT AREAS
FAVORED BY NNW WINDS OVER THE WEST AND NW TO WNW WINDS OVER THE ERN
CWA WOULD SEE THE HEAVIEST SNOWFALL. WITH 850 MB TEMPS DOWN TO NEAR
-13C (LAKE -H8 DELTA/T TO AROUND 19C) AND DEEPER MOISTURE LEADING TO
FAVORABLE SNOW GROWTH....LOCALLY HEAVY SNOWFALL RATES MAY BE
POSSIBLE. WILL CONTINUE TO HIGHLIGHT IN THE HWO FOR NOW WITH
LIKELIHOOD OF SOME LES HEADLINES AS THE EVENT COMES INTO BETTER
FOCUS.
SAT-MON...THE COLD AIR...850 MB TEMPS STILL IN THE -12C TO -14C
RANGE... IS EXPECTED TO LINGER THROUGH THE WEEKEND WITH LES
CONTINUING EVEN AS THE WINDS DIMINISHING AND BACKING MORE WRLY. IF
WINDS BECOME LIGHT ENOUGH...POTENTIAL WILL EXIST FOR GREATER
MESOSCALE INFLUENCE ON LES BAND LOCATION.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
LIGHT LAKE EFFECT SNOW SHOWERS WILL CONTINUE THROUGH THE MORNING AT
CMX. THIS WILL ALSO ALLOW FOR MVFR CIGS TO PERSIST THROUGH THE
PERIOD AT CMX. VFR CONDITIONS WILL CONTINUE AT SAW AS LAKE EFFECT
CLOUDS SHOULD STAY TO THE NORTH AND EAST WITH WINDS BEING
NORTHWESTERLY.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
A CLIPPER SYSTEM WILL PASS THROUGH LAKE SUPERIOR THIS EVENING
ALLOWING WINDS TO 30 KNOTS AT TIMES. WEAK HIGH PRESSURE BUILDS OVER
THE UPPER GREAT LAKES ON TUESDAY ALLOWING WINDS TO GO LIGHT AS
TONIGHT/S CLIPPER MOVES TO THE LOWER LAKES. AT THE SAME TIME...LOW
PRESSURE OVER THE NORTH DAKOTA SHIFTS EAST AND CROSSES LAKE SUPERIOR
ON WEDNESDAY. GALE FORCE GUSTS TO 35 KNOTS ARE POSSIBLE AS THIS
FEATURE MOVES ACROSS THE LAKE. BEHIND IT...NORTHERLY WINDS OF 25 TO
30 KNOTS ARE EXPECTED INTO THURSDAY AS A STRONG LOW PRESSURE MOVES
UP THE APPALACHIANS ON ITS WAY TO THE CANADIAN MARITIMES THURSDAY
NIGHT. EXPECT NORTHWESTERLY WINDS OF 20 TO 25 KNOTS FOR FRIDAY AND
SATURDAY AS A LOW PRESSURE TROUGH REMAINS OVER THE GREAT LAKES
REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DJP
LONG TERM...JLB
MARINE...DJP
AVIATION...07
