Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 261144
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
644 AM EST FRI DEC 26 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 433 AM EST FRI DEC 26 2014

CONCERNS FOCUS ON LIGHT PCPN TODAY ALONG SFC TROUGH MOVING SLOWLY
EASTWARD ACROSS THE AREA...THEN THE POTENTIAL FOR MODERATE SNOW LATE
TONIGHT INTO SATURDAY OVER CENTRAL AND ERN UPPER MI AS WAVE FROM SW
CONUS EJECTS NE ALONG SFC TROUGH.

WATER VAPOR IMAGERY SHOWS A WEAK SHORTWAVE LIFTING NE THROUGH SRN MN
INTO UPPER MI. MODELS INDICATE WEAK TO MODERATE Q-VECT CONV AND
800-750 MB FGEN FORCING ASSOC WITH THIS SHORTWAVE WILL SUPPORT A
BAND OF LIGHT SNOW OVER MAINLY THE NW PORTION OF THE CWA THIS
MORNING WITH THE BAND MOVING SLOWLY EAST INTO NCNTRL AND ERN UPPER
MI THIS AFTERNOON. MODEL AVERAGED QPF OF .06-.08 INCH ALONG WITH A
12/1 SLR COULD YIELD HALF AN INCH TO ONE INCH OF SNOW OVER FAR WRN
UPPER MI TODAY WITH ONLY A DUSTING OF SNOW EXPECTED ELSEWHERE ACROSS
THE NRN TIER. WEAK UPSLOPE SRLY FLOW AND SHALLOW MOISTURE BLO DGZ
COULD YIELD SOME PATCHY DZ/FZDZ OVER THE SE CWA. LAKE ENHANCEMENT
FOR WRN COUNTIES WILL LIKELY BE MINIMAL LATE TODAY IN DEVELOPING NW
FLOW DUE TO MARGINAL 8H TEMPS OF -8 TO -9C AND FAIRLY SHALLOW
MOISTURE.

TONIGHT...A SHORTWAVE EJECTING FROM A TROF OVER THE SRN ROCKIES IS
FCST TO STREAK NE INTO THE GREAT LAKES. MODERATE Q-VECT CONV AND
INCREASING 285-290K ISENTROPIC ASCENT ASSOC WITH THE SHORTWAVE ALONG
WITH A DEEPENING MOISTURE PROFILE AND GOOD UPWARD MOTION THROUGH DGZ
COULD LEAD TO A WIDESPREAD 1-1.5 INCHES LATE TONIGHT ACROSS MUCH OF
THE CWA ESPECIALLY THE CENTRAL. WITH MODELS SUGGESTING 285-290K
ISENTROPIC ASCENT AND GOOD DENDRITIC SNOW GROWTH CONTINUING INTO SAT
AFTERNOON OVER MUCH OF THE ERN HALF OF THE CWA...WOULD NOT BE
SURPRISED TO SEE SOME ERN HALF COUNTIES REACH ADVISORY CRITERIA WITH
TOTAL SNOWFALL LATE TONIGHT INTO SATURDAY APPROACHING FOUR INCHES AT
SOME LOCATIONS. SINCE MUCH OF THE SNOW WILL FALL SATURDAY (THIRD FCST
PD) WILL HOLD OFF ON ISSUING ADVISORY FOR NOW BUT WILL CONTINUE TO
MENTION POTENTIAL FOR MODERATE SNOW ACCUMULATION IN HWO.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 510 AM EST FRI DEC 26 2014

WILL START OFF SATURDAY MORNING IN THE MIDDLE OF WET SNOW FALLING
ACROSS CENTRAL AND EASTERN UPPER MI. ADDITIONAL DAYTIME
ACCUMULATIONS AT THIS POINT LOOK BE BE 1 TO 3IN. CONFIDENCE IS
GROWING...WITH THE OPERATIONAL MODEL RUNS INDICATING THE SFC LOW
ALONG THE WI/IL BORDER AT 12Z SATURDAY LIFTING ACROSS N LOWER/FAR E
UPPER MI BY 18Z...AND THEN JUST N OF GEORGIAN BY BY 00Z SUNDAY. THE
26/00Z RUN OF THE ECMWF WAS ORIGINALLY FARTHER W...SLOWER...AND
DEEPER...BUT HAS COME GENERALLY IN LINE WITH THE 26/00Z
NAM/GFS/CANADIAN. AS NOTED IN THE SHORT TERM DISCUSSION THE NEEDED
FOR A WINTER WX HEADLINE OF SOME SORT MAY BE NEEDED. A WINTER WX
ADVISORY MAY COVER IT /3-6IN IN A 12 HOUR PERIOD/. THE 18-24 HOUR
DURATION OF THIS EVENT MAKES IT VERY BORDERLINE.

HIGH PRESSURE OVER THE PLAINS STATES WILL TAKE LITTLE TIME TO SLIDE
IN BEHIND THE EXITING LOW SATURDAY EVENING ALONG THE WI
BORDER...HELPING TO GIVE THE AREA A BREAKER BETWEEN THE EXITING
SYNOPTIC SNOW AND THE DEVELOPMENT OF LAKE EFFECT SHOWERS.

W SFC-850MB FLOW AT 00Z SUNDAY UNDER 850MB TEMPS AROUND -11C WILL
REMAIN LESS THAN IDEAL AND VARYING IN DIRECTION AT THE LOW LEVELS
UNTIL COOLER AIR ARRIVES LATE SUNDAY AFTERNOON INTO SUNDAY EVENING.
LOOK FOR SNOW RATIOS TO RETURN TO 20:1 OR MORE FROM SUNDAY MORNING
ON. STILL WITH A SFC TROUGH LINGERING ACROSS S LAKE SUPERIOR SUNDAY
MORNING...THE FOCUS FOR SNOW SHOWERS WILL REMAIN.

OTHERWISE...THE MAIN STORY FOR THIS PERIOD WILL BE THE PROLONGED
PERIOD OF MAINLY NW WINDS LATE SUNDAY THROUGH AT LEAST MONDAY
EVENING...THANKS IN PART TO THE LARGER/COOL HIGH PRESSURE AREA
BUILDING IN FROM NW CANADA. DURING THIS TIME 850MB TEMPS SHOULD BE
AROUND -17C TO -21C. LOOK FOR ADDITIONAL SNOW OF 1-2 IN TO LOCALLY 3
WHERE THE WIND FOCUSES NEAR LAKE SUPERIOR.

THE LARGE HIGH SHOULD SINK INTO THE CENTRAL AND S PLAINS BY
WEDNESDAY. THIS WILL LEAVE THE UPPER GREAT LAKES BETWEEN THIS HIGH
AND A NEARING LOW FROM ONTARIO TUESDAY NIGHT INTO EARLY WEDNESDAY.
AS NOTED...BLOWING SNOW COULD BE A CONCERN ALONG LAKE SUPERIOR AS
WINDS INCREASE WITH THE INCREASED PRESSURE GRADIENT. THE LOW TO THE
N SHOULD SLIP ACROSS S ONTARIO AND NE LAKE SUPERIOR WEDNESDAY
AFTERNOON...LEAVING ANOTHER TROUGH ACROSS LAKE SUPERIOR FOR THE REST
OF THIS FCST PERIOD. WILL BE DIFFICULT TO HAVE AREAS DRY FOR ANY
PROLONGED PERIOD ACROSS THE KEWEENAW PENINSULA...OR E OF MUNISING
ALONG LAKE SUPERIOR.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 632 AM EST FRI DEC 26 2014

LOOK FOR A WEAK DISTURBANCE TO BRING SOME LIGHT SNOW TO THE WESTERN
TAF SITES MAINLY THIS MORNING WITH IFR TO LOW MVFR CONDITIONS.
CONDITIONS SHOULD SLOWLY IMPROVE TO MVFR AT ALL TAF SITES THIS
AFTERNOON BEFORE DIMINISHING AGAIN LATE THIS EVENING INTO EARLY
SATURDAY AHEAD OF ANOTHER DISTURBANCE MOVING UP FROM THE CENTRAL
PLAINS. THE ONSET OF SNOW WILL LOWER CONDITIONS TO IFR AT BOTH KIWD
AND KSAW AFT 06Z SUNDAY. THE POTENTIAL FOR MODERATE SNOW AT KSAW
COULD LOWER CONDITIONS TO LIFR THERE.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 433 AM EST FRI DEC 26 2014

A TROUGH HANGING OVER THE AREA TODAY WILL KEEP THE PRES GRADIENT
WEAK AS WINDS REMAIN GENERALLY BLO 20 KT THROUGH TONIGHT. A LOW
MOVING NORTHEAST ALONG THE TROUGH ON SATURDAY WILL INCREASE THE
NORTH AND EVENTUALLY NORTHWEST WINDS ON SATURDAY AFTERNOON AND
SATURDAY NIGHT...WITH GUSTS UP TO 30KTS OVER THE EASTERN LAKE. THE
REST OF THE PERIOD WILL EXPERIENCE NORTHWEST TO NORTHERLY WINDS
UNDER 25KTS AS A STRONG HIGH BUILDS INTO THE NORTHERN/CENTRAL PLAINS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS





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