FXUS63 KMQT 260043 AAA
AFDMQT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MARQUETTE MI
743 PM EST FRI DEC 25 2009
UPDATED FOR 00Z AVIATION DISCUSSION
.SHORT TERM (TONIGHT/SAT)...
EXPANSIVE MID/UPPER LOW ENCOMPASSES THE CNTRL CONUS FROM THE ROCKIES
TO THE APPALACHIANS. ONE STRONG SHORTWAVE HAS ROTATED WWD INTO SRN
MN/NRN IA. SEVERAL MORE SHORTWAVES ARE NOTED ROTATING IN THE LARGE
CIRCULATION. ONE WAS LIFTING THRU NRN LAKE MI...ANOTHER WAS OVER
IL...AND A STRONGER WAVE WAS OVER KS/MO. AS UPSTREAM SHORTWAVES
ROTATE THRU THE CIRCULATION...PCPN WILL LIKELY EXPAND AGAIN THIS
EVENING OVER THE WRN GREAT LAKES. MODELS HAVE HAD A REASONABLE
HANDLE ON COOLING COLUMN THIS AFTN AS PCPN WHICH WAS MOSTLY LIQUID
HAS BEEN CHANGING MORE TO SNOW OVER ROUGHLY THE W HALF OF UPPER MI.
THIS PROCESS WILL CONTINUE EWD DURING THE NIGHT. WHILE SNOW AMOUNTS
SHOULDN'T BE MORE THAN A FEW INCHES AT ANY LOCATION...HAVE SOME
CONCERN THAT THE INCREASINGLY WELL DEFINED NATURE ON WATER VAPOR
IMAGERY OF ONE OF THE SHORTWAVES HEADING INTO THE WRN GREAT LAKES
COULD RESULT IN THE DEVELOPMENT OF HEAVIER PCPN THAN CURRENTLY
EXPECTED. WILL NEED TO MONITOR TRENDS OVER THE NEXT SEVERAL HRS TO
DETERMINE IF SNOW AMOUNTS MAY NEED TO BE ADJUSTED UPWARDS OR ADVYS
EXPANDED. IN ANY EVENT...OPTED TO MAINTAIN GOING ADVY HEADLINES OVER
THE W HALF AS WET/SLUSHY SNOW ACCUMULATION ON ROADWAYS WILL MAKE FOR
ESPECIALLY HAZARDOUS TRAVEL TONIGHT. IN GENERAL...MODELS ARE TENDING
TO FOCUS HIGHER PCPN TOTALS OVER THE SE HALF OF THE FCST AREA
TONIGHT. IF THE MODELS ARE ON THE RIGHT TRACK WITH PCPN AMOUNTS...
ADVYS MAY BE NEEDED OVER THE ERN FCST AREA IF PCPN CHANGES TO SNOW
EARLY THIS EVENING.
OCCLUDED FRONT WILL LIFT THRU THE AREA LATE TONIGHT/SAT MORNING...
BRINGING CAA FROM THE S. AIRMASS SHOULD COOL ENOUGH FOR LES OFF LAKE
MICHIGAN IN SE TO S FLOW. MODELS SHOW A VARIETY OF WIND FIELD
SOLUTIONS WITH SOME OF THE HIGHER RESULUTION MODELS SHOWING A
TENDENCY FOR MORE FOCUSED CONVERGENCE...RESULTING IN A DOMINANT
MDT/HVY SNOW BAND DEVELOPING OVER NRN LAKE MI. THIS COULD AFFECT
PORTIONS OF SCHOOLCRAFT AND DELTA COUNTIES AND POSSIBLY SOME OF
MENOMINEE COUNTY. LITTLE CONFIDENCE IN THE DETAILS AT THIS POINT.
FOR NOW...INCLUDED AN AREA OF HIGHER POPS OVER THE SE FCST AREA WITH
SNOW ACCUMULATIONS OF 1-3 INCHES. ELSEWHERE...EXPECT PERIODIC
-SHSN.
TEMPS SHOULD REMAIN FAIRLY STEADY TONIGHT...THEN FALL LATE TONIGHT
THRU SAT MORNING WITH PASSAGE OF OCCLUDED FRONT. LITTLE OR NO TEMP
RECOVERY SAT AFTN.
.LONG TERM...00Z SUN ONWARD...
WINTER STORM WILL CONTINUE TO AFFECT THE AREA ON SAT NIGHT AND SUN
AS THE 500 MB CLOSED LOW OVER WI SLOWLY MEANDERS ESE AND THEN GETS
KICKED TO THE EAST AS A REINFORCING SHOT OF COLD AIR COMES DOWN ON
MON AND KICKS THE ASSOCIATED LOW OUT.
SYSTEM LAKE ENHANCED SNOW THROUGH SUNDAY NIGHT WILL CONTINUE TO BE
THE WEATHER FOR THIS FORECAST WITH LAKE MICHIGAN LAKE ENHANCED SNOW
SAT NIGHT AND THEN LAKE SUPERIOR ENHANCED SNOWFALL FOR SUNDAY AND
SUNDAY NIGHT. THIS IS ALL DEPENDENT ON WIND DIRECTION. THE LAKE-850
MB DELTA-T IS MARGINAL THOUGH WITH LAKE WATER TEMPERATURES AROUND 4C
AND 850 MB TEMPERATURES AROUND -8C TO -10C OR SO. STILL COULD SEE A
COUPLE OF INCHES IN A FEW SPOTS...BUT THE SNOW SHOULD REMAIN LIGHT.
DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR TEMPERATURES
OR FOR WEATHER OTHERWISE.
NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE ALONG WITH SOME
DEEPER MOISTURE WITH THE REINFORCING COLD AIR ON MON MOVING THROUGH
THE AREA AND GFS SHOWS ABOUT THE SAME THING AS WELL. ONE THING
THOUGH IS THIS REINFORCING COLD SHOT LOOKS TO BE A GLANCING BLOW
WITH THE FULL BRUNT OF IT TO THE NORTHEAST OF THE AREA. QUICKLY
LOOKED AT SOUNDINGS FROM THE NAM AND GFS FOR KCMX AND KERY AND BOTH
SHOW THE COLD AIR IS VERY SHALLOW WITH THE INVERSION HEIGHT GETTING
UP TO 5000 TO 6000 FEET OR SO AT KERY OFF THE NAM AND 3500 TO 5000
FEET BRIEFLY AT KCMX BY 18Z MON WITH THE HIGHER HEIGHTS OFF THE NAM
AND LOWER HEIGHTS FROM THE GFS. BOTH MODELS THOUGH SHOW AN
INVERTED-V SOUNDING LOOK TO THEM WHICH SHOULD KEEP THE LAKE EFFECT
SNOW IN CHECK AND NOT LET IT GET TOO OUT OF HAND EVEN IF THE
INVERSION LEVELS ARE MODERATE ON THE LAKE EFFECT SNOW CHART. DRY AIR
AT THE LOW LEVELS WOULD ALSO CUT INTO THE LAKE EFFECT SNOW MACHINE
WHICH SHOULD LIMIT INTENSITY AND COVERAGE A BIT AS WELL. STILL
THOUGH...COULD SEE A COUPLE OF INCHES OF SNOW IN THE NORTH TO
NORTHWEST LAKE SUPERIOR LAKE EFFECT SNOWBELTS. TEMPERATURES MODIFY
ON TUE THEN AND WARM AHEAD OF THE NEXT CLIPPER TYPE SYSTEM WHICH
SHOULD TEMPER THE LAKE EFFECT SNOW A BIT AS WELL.
IN THE EXTENDED...GFS...ECMWF AND CANADIAN SHOW A DEEP CLOSED 500 MB
LOW OVER NE CANADA WITH A TROUGH ACROSS THE EASTERN U.S. 00Z TUE
WITH A BROAD TROUGH MOVING INTO THE CENTRAL U.S. 00Z WED. THIS
TROUGH REMAINS FOR 00Z THU AND MOVES INTO THE UPPER GREAT LAKES AND
REMAINS THROUGH THE REST OF THE EXTENDED. WILL REMAIN UNSETTLED WITH
LAKE EFFECT AND LIGHT CLIPPER SYSTEM SNOW FOR MOST OF THE PERIOD.
TEMPERATURES LOOK TO STAY COOLER WITH TEMPERATURES NEAR NORMAL OR
SLIGHTLY BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/...
KCMX...EXPECT LIFR CIGS TO IMPROVE TO IFR AFT 08Z TONIGHT AND THEN
IMPROVE TO MVFR BY LATE SATURDAY MORNING AS THE PASSAGE OF AN
OCCLUDED FRONT SHIFTS WINDS FROM UPSLOPE EAST TO DOWNSLOPE S-SE
DIRECTION. IFR VSBYS IN SNOW SHOULD ALSO IMPROVE TO VFR WITH THE
PASSAGE OF THE OCCLUDED FRONT AS S-SE WINDS WILL NO LONGER SUPPORT
ANY LAKE ENHANCED SNOW.
AT KSAW...A MOIST ESE FLOW WILL CONTINUE TO SUPPORT MVFR TO IFR
CONDITIONS IN SHSN THIS EVENING. PASSAGE OF THE OCCLUDED FRONT WILL
ALLOW CONDITIONS TO IMPROVE TO MVFR LATE TONIGHT AS DRIER AIR WORKS
IN FROM THE SOUTH. CYCLONIC S-SE FLOW WILL CONTINUE TO SUPPORT SOME
LIGHT SNOW/FLURRIES ON SATURDAY AS CIGS REMAIN IN THE MVFR RANGE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 PM EST /9 PM CST/ THIS
EVENING MIZ001>005-009>012-084.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 AM EST SATURDAY LSZ266-267.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SATURDAY
LSZ162-244-245-263>265.
GALE WARNING UNTIL 11 PM EST THIS EVENING LSZ246-250-251.
LAKE MICHIGAN...
GALE WARNING UNTIL 11 PM EST THIS EVENING LMZ221-248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...VOSS
