FXUS63 KMQT 101137 AAA
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
632 AM EST THU DEC 10 2009
.DISCUSSION...
UPPER AIR PATTERN CONSISTS OF A DEEP TROUGH ACROSS THE CENTRAL U.S.
WITH PLENTY OF COLD AIR WITH A 500 MB LOW NE OF LAKE SUPERIOR WHICH
BROUGHT THE BIG WINTER STORM TO THE U.P. YESTERDAY. THE 500 MB
TROUGH WILL STICK AROUND A WHILE AND CONTINUE TO BRING COLD AIR TO
THE AREA FOR A WHILE AND LAKE EFFECT SNOW WHICH THE WIND DIRECTION
WILL PLAY A CRUCIAL ROLE IN WHICH AREAS GET SNOW AND ALSO HOW MUCH.
UPPER AIR PATTERN THIS WEEKEND THEN GOES TO SLIGHTLY MORE ZONAL FROM
WNW TO ESE ACROSS THE AREA WHICH SHOULD MODIFY THE COLD ARCTIC AIR A
BIT AS WELL.
BESIDES LAKE EFFECT...THERE WILL ALSO BE A WEAK SYSTEM FOR SAT AS
BOTH NAM AND GFS BOTH SHOW 850-500 MB Q-VECTOR CONVERGENCE COMING
THROUGH THEN.
EXTREMELY BUSY NIGHT WITH MANY HEADLINES AND PRODUCTS TO WRITE AND
WILL HIT THE HIGH POINTS ONLY.
CHANGED THE WINTER STORM WARNINGS TO LAKE EFFECT SNOW WARNINGS NOW
SINCE THE STORM HAS MOVED AWAY. THESE LAKE EFFECT SNOW WARNINGS ARE
HIGHLY DEPENDENT ON WIND DIRECTION AND WHEN THE WIND CHANGES
DIRECTION...THIS WILL DICTATE WHEN THE SNOW SHOWERS WILL MOVE OUT.
THE WIND WILL GO TO MORE WEST SOUTHWEST TONIGHT EAST OF MUNISING AND
THAT IS WHY THE WARNING WILL NOT GO INTO TONIGHT. ONLY A SMALL PART
OF ALGER AND LUCE COUNTIES WOULD BE AFFECTED BY LAKE EFFECT SNOW
SHOWERS FROM THAT. OPTED TO GO WITH ADVISORIES FOR ONTONAGON AND
SOUTHERN HOUGHTON COUNTIES DUE TO FACT THAT AREAS AFFECTED WILL BE
VERY SMALL. THERE WILL BE WARNING AMOUNTS IN A SMALL AREA NORTH OF
HIGHWAYS OF M-26 AND M-38 WHERE MOST PEOPLE DO NOT LIVE AND DID NOT
WANT TO WARN FOR THE WHOLE COUNTY WHEN ONLY A REALLY SMALL AREA IS
BEING AFFECTED...SO THOUGHT ADVISORY FOR THOSE TWO PLACES IS THE WAY
TO GO. NORTHERN HOUGHTON AND KEWEENAW COUNTIES...A DOMINANT WEST
BAND WILL SET UP SIMILAR TO LAST WEEKEND FOCUSED IN LARGE PART BY
STRONG CONVERGENCE AND FORECASTED UP 16 TO 30 INCHES OF SNOW IN THIS
BAND FROM TODAY THROUGH FRIDAY NIGHT AS THE WIND DIRECTION AND
CONVERGENCE DOES NOT CHANGE MUCH AND THIS BAND WILL BE SOMEWHAT
STATIONARY THROUGH ABOUT 48 HOURS. FINALLY ON SAT...THE WIND BECOMES
SOUTHWEST ENOUGH TO PUSH THIS BAND BACK OFFSHORE.
ISSUED A WIND CHILL ADVISORY FOR MOST OF THE WESTERN HALF OF UPPER
MICHIGAN TONIGHT AND DROPPED LOWS TO NEAR ADJMET GUIDANCE WHICH WAS
THE COLDEST AVAILABLE. IT WILL BE QUITE COLD WITH SOME CLEAR SKIES
AND WIND CHILLS WILL FALL TO 15 TO 30 BELOW ZERO TONIGHT THROUGH FRI
MORNING WHERE IT IS NOT SNOWING OR WHERE IT IS NOT CLOUDY.
FINALLY...LAKE ENHANCED SNOW FROM LAKE MICHIGAN LOOKS LIKELY SAT
AFTERNOON AND SAT NIGHT WITH WINDS FROM THE SOUTH OFF LAKE MICHIGAN
AND IT IS COLD ENOUGH FOR LAKE EFFECT. BUMPED POPS UP TO LIKELY
ACROSS THE EASTERN CWA TO ACCOUNT FOR THIS AND WILL HAVE TO WATCH AS
THERE IS A WEAK SYSTEM GOING THROUGH AS WELL. MIGHT HAVE ADVISORY
TYPE SNOW WITH THIS. WILL PASS THIS CONCERN ON TO DAYSHIFT AND THEY
CAN LOOK CLOSER AT IT.
OVERALL...DID NOT MAKE TOO MANY CHANGES TO TEMPERATURES OR TO GOING
FORECAST. MAIN CHANGES WERE HEADLINE CHANGES AND BUMPED UP SOME SNOW
AMOUNTS IN A FEW PLACES.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
KSAW...PERSISTENT WESTERLY WINDS WILL ALLOW FOR VFR CONDITIONS
TO CONTINUE AT LEAST THROUGH THE AFTERNOON. AN OCCASIONAL LES BAND
PASSING OVER THE AIRPORT WILL LOWER CEILING TO MVFR. THEREAFTER..AS
WINDS STEADILY SHIFT TO THE WEST BY THIS EVENING...CEILING SHOULD
BECOME STEADY VFR BY LATE THIS AFTERNOON. LIGHT SNOW MAY CONTINUE AS
WINDS BRING LES FROM KEWEENAW PENINSULA INTO KSAW AREA.
KCMX...WEST WINDS AND LAKE EFFECT SNOWS WILL KEEP IFR CONDITIONS
GOING THROUGHOUT THE TODAY WITH CONDITIONS DETERIORATE TO LIFR OR
WORSE AS HEAVY SNOW BANDS RETURNS TO KCMX. A LITTEL DRIER AIR MOVING
INTO THE AREA WILL CAUSE CONDITIONS TO IMPROVE OCCCASIONALLY LATE
TONIGHT TO MVFR.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
GALE WARNINGS WILL CONTINUE OVER PARTS OF THE LAKE UNTIL SUNRISE
THIS MORNING AS THE VERY DEEP LOW PRESSURE SYSTEM OVER SOUTHWEST
QUEBEC DEPARTS TO THE EAST. COLDER AIR MOVING INTO THE REGION HAS
HELPED MIX THE STRONG 925-850 MB WINDS TO THE SURFACE AND WILL ALSO
RESULT IN SOME FREEZING SPRAY. PLEASE SEE THE LATEST MARINE HAZARD
MESSAGE FOR FURTHER DETAILS.
ON TONIGHT THROUGH FRIDAY NIGHT...THERE MAY BE SOME LOCALIZED W
GALES MAINLY OVER THE EASTERN LAKE SUPERIOR ON THE SOUTHERN FLANK OF
LOW PRESSURE STRETCHING FROM WESTERN LAKE SUPERIOR ACROSS THE
KEWEENAW INTO CENTRAL LAKE SUPERIOR. HOWEVER...THESE STRONGER WINDS
WILL NOT BE WIDESPREAD ENOUGH TO JUSTIFY A GALE WATCH. OVERALL
H925-85 WINDS ARE AROUND 30 KTS...WHICH WILL READILY MIX TO THE
SURFACE WITH VERY COLD AIR RESULTING IN STEEP LLVL LAPSE RATES.
FREEZING SPRAY WILL PERSIST. WINDS WILL BE NO MORE THAN 15 TO 25 KTS
THIS WEEKEND...BUT STRONGER NW 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...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR MIZ002-084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR MIZ001-003.
WIND CHILL ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO 11
AM EST /10 AM CST/ FRIDAY FOR MIZ004-005-009>013.
LAKE EFFECT SNOW ADVISORY UNTIL 10 AM CST THIS MORNING FOR
MIZ009.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 PM EST FRIDAY FOR LSZ266-267.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ243>245-264-265.
LAKE MICHIGAN...NONE.
&&
$$
AVIATION...DLG
MARINE...DLG
DISCUSSION...07
