FXUS63 KMQT 111127 AAA
AFDMQT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MARQUETTE MI
626 AM EST FRI DEC 11 2009

.UPDATED FOR AVIATION...
&&

.DISCUSSION...

UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE CENTRAL U.S. 
WHICH WILL REMAIN ENTRENCHED OVER THE AREA TODAY. ZONAL FLOW THEN 
BEGINS THIS WEEKEND IN THE UPPER LEVELS WHICH WILL LEAD TO SLOW 
MODIFICATION OF TEMPERATURES. IN THE MEANTIME...LAKE EFFECT SNOW 
WILL CONTINUE AND THERE WILL ALSO BE WEAK DISTURBANCES PASSING BY 
VERY ONCE IN A WHILE AS WELL.

NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE AND SOME MOISTURE 
TONIGHT PASSING ACROSS THE AREA WITH THE MAJORITY OF THE MOISTURE 
STAYING NORTH OF THE CWA. MORE 850-500 MB Q-VECTOR CONVERGENCE MOVES 
IN FOR SUN ALONG WITH SOME MOISTURE WITH ANOTHER DISTURBANCE AS WELL 
AND ANOTHER FOR MON. MON SYSTEM LOOKS A LITTLE MORE POTENT WITH A 
BIT MORE MOISTURE. 

WILL AGAIN HIGH THE MAIN POINTS OF WHAT CHANGES WERE MADE WHICH 
REALLY WERE NOT THAT MANY. GOING FORECAST HAD THINGS PRETTY WELL IN 
HAND WITH THE LAKE EFFECT EXCEPT HAD TO TRIM POPS BACK A BIT AS THEY 
WERE HIGHLY DEPENDENT ON WIND DIRECTION. WITH A WEST 
DIRECTION...THIS TAKES MOST OF THE SNOW SHOWERS OUT OF ALGER AND 
LUCE COUNTIES WHICH HAS BEEN THE CASE ALL NIGHT. THE SNOW IS FALLING 
IN A NARROW BAND ABOUT 10 MILES WIDE ACROSS THE FAR NORTHERN 
PORTIONS OF THOSE COUNTIES WITH THE MAJORITY OF THE COUNTY SNOW 
FREE. THE WINDS WILL BACK A BIT MORE SOUTHWEST THIS MORNING WHICH 
WILL CONTINUE TO CONFINE THE SNOWSHOWERS TO A NARROW ZONE. FOR THIS 
REASON...CANCELLED THE LAKE EFFECT SNOW WARNINGS FOR ALGER AND LUCE 
COUNTIES. ONTONAGON HAD PRETTY MUCH THE SAME DILEMMA THERE. ONLY THE 
VERY FAR NORTHERN PORTION OF THE COUNTY WAS SEEING ANYTHING. DECIDED 
TO DROP THE LAKE EFFECT SNOW WARNING AND GO WITH AN ADVISORY INSTEAD 
ACROSS THE NORTHERN PORTION OF THE COUNTY...AGAIN FOR ONLY ABOUT A 
10 MILE WIDE STRETCH ALONG THE LAKE SUPERIOR SHORELINE DUE TO THE 
WEST WIND. THE WIND FINALLY GOES SOUTHWEST THIS EVENING WHICH SHOULD 
PULL THE BAND OUT OF EXTREME NORTHERN ONTONAGON COUNTY AND PUSH IT 
OFFSHORE. 

AS FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES...DID NOT CHANGE 
ANYTHING EITHER AS THE WIND DOES NOT GO SOUTH UNTIL AFTER MIDNIGHT 
WHICH SHOULD SLOWLY PUSH THE HEAVY LAKE EFFECT SNOW BAND NORTH 
ACROSS THE TWO COUNTIES AND FINALLY OFFSHORE BY DAYBREAK. STILL 
COULD SEE UP TO 18 INCHES OF SNOW WITH THIS HEAVY SNOW BAND THROUGH 
TONIGHT THOUGH. 

KEPT SLIGHT CHANCE POPS IN FOR SNOW FOR SAT AND SAT NIGHT WITH WAA 
SETTING UP WITH SLIGHTLY HIGHER POPS OVER THE EASTERN CWA DUE TO 
SOME LAKE MICHIGAN ENHANCEMENT WITH A SOUTHWEST WIND THERE. FOR 
SUN...DISTURBANCE COMES THROUGH AND KEPT CHANCE POPS IN THERE FOR 
SNOW FROM THAT. DID BUMP POPS UP SUN NIGHT AND MON FOR NEXT SYSTEM 
THAT HAS A BIT MORE MOISTURE WITH IT AND THIS SYSTEM ACCORDING TO 
THE NAM...GFS AND ECMWF COULD DUMP A COUPLE INCHES OF SNOW ON THE 
AREA THEN. BUMPED POPS UP TO LIKELY ACROSS THE CWA WITH SOME HELP 
FROM LAKE ENHANCEMENT. OVERALL...THESE WERE THE ONLY CHANGES I MADE. 
DID NOT TOUCH TEMPERATURES TOO MUCH...BUT SLOW WARMING TREND IS ON 
THE WAY.

&&

.AVIATION /FOR THE 12Z TAF ISSUANCE/...

LOCATION OF SHARP AXIS OF LOW LEVEL CONVERGENCE/ACCOMPANYING HEAVY 
LES BAND STRETCHING ACROSS WRN LAKE SUPERIOR AND THROUGH THE 
KEWEENAW WILL CAUSE LAKE AFFECT SNOW BANDS TO OCCILLATE ACROSS KCMX 
TODAY AND TONIGHT. ALTHOUGH THE HEAVIER BAND ARE LIKELY TO REMAIN 
JUST S OF CMX...RECENT OBSERVATION SUGGEST IFR/OCCASIONAL LIFR 
CONDITIONS WILL PREVAIL. AS FLOW BACKS AGAIN TOWARD SUNRISE...EXPECT 
THE BAND TO DRIFT NORTH ACROSS CMX WITH VLIFR CONDITIONS. WITH 
CONTINUED BACKING FLOW...THE HEAVIER BAND WILL DRIFT JUST TO THE 
NORTH THIS AFTERNOON WITH IMPROVING CONDITIONS AS VERY DRY ARCTIC 
AIR OVERSPREADS THE LAKE SUPERIOR. NOTE SUBTLE CHANGES IN OBS VS 
FCST WIND DIRECTION WOULD HAVE SIGNIFICANT CHANGES IN BAND 
PLACEMENT/CONDITIONS.

THE FCST IS MUCH LESS OF A CHALLENGE AT SAW WITH VFR CONDITIONS 
PREDOMINATING THIS FCST PERIOD IN LOW LEVEL DOWNSLOPING SOUTHWEST 
FLOW OF DRY ARCTIC AIR THAT WILL KEEP LES BANDS WELL NORTH OF THE 
AIRPORT. 

&&

.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...

WEST GALES THROUGH TODAY...MAINLY OVER EASTERN LAKE SUPERIOR ON THE 
SOUTHERN FLANK OF LAKE SUPERIOR INDUCED LOW PRESSURE TROUGH. 
ELSEWHERE...WINDS TO 30 KTS PERSIST ALONG WITH FREEZING SPRAY. WINDS 
REMAIN BELOW 25 KTS THROUGH THE WEEKEND...BUT STRONGER WINDS TO 30 
KTS MAY ARRIVE EARLY NEXT WEEK AS ANOTHER ARCTIC AIRMASS MOVES INTO 
THE UPPER GREAT LAKES.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR   
     MIZ002-004-005-009>013-084.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002. 

  LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR MIZ001-003.

LAKE SUPERIOR...
  GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ266-267.

LAKE MICHIGAN...NONE.

&&

$$

AVIATION...DLG
MARINE...DLG
DISCUSSION...07