Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 260041
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
741 PM EST SUN JAN 25 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 244 PM EST SUN JAN 25 2015

THE UPPER GREAT LAKES IS BETWEEN CLIPPER SYSTEMS THIS
AFTERNOON...WITH THE FIRST ONE MOVING INTO THE OHIO RIVER VALLEY AT
THIS TIME...WITH THE SECOND ONE ROUNDING THE UPPER RIDGE OVER THE
WESTERN CONUS. BETWEEN THESE TWO CLIPPERS...AN AREA OF HIGH PRESSURE
IS LOCATED OVER NORTHERN ONTARIO AND IS STRETCHING A RIDGE OVER THE
UPPER GREAT LAKES REGION. THIS RIDGE HAS LED TO WEAKENING WINDS OVER
THE CWA THROUGH THE DAY TODAY AND WHEN COMBINED WITH THE LOWERING
SUBSIDENCE INVERSION (SEEN ON KMQT VAD)...HAS DIMINISHED THE LAKE
EFFECT SNOW SHOWERS OVER THE AREA FROM THIS MORNING. BUT THERE ARE
STILL SNOW SHOWERS OVER THE NORTH CENTRAL AND KEWEENAW. THESE SNOW
SHOWERS WILL CONTINUE TO SLOWLY DIMINISH THROUGH THE EVENING AND
THEN WHAT IS LEFT OVER WILL SHIFT NORTH OVER LAKE SUPERIOR AS THE
SOUTHERLY WINDS DEVELOP AHEAD OF THE NEXT CLIPPER SYSTEM.

THAT NEXT CLIPPER SYSTEM (CURRENTLY MOVING THROUGH NORTHERN
SASKATCHEWAN) WILL DROP SOUTHEAST AND THROUGH THE AREA LATE TONIGHT
AND MONDAY. THERE ARE TWO EMBEDDED WAVES OF ENERGY ASSOCIATED WITH
THIS CLIPPER SYSTEM THAT WILL AFFECT THE AREA. THE FIRST WAVE WILL
MOVE INTO THE MINNESOTA ARROWHEAD SHORTLY AFTER 06Z TONIGHT AND THEN
QUICKLY DIVE SOUTHEAST ACROSS WESTERN LAKE SUPERIOR AND NORTHWEST
WISCONSIN BY 12Z MONDAY. THE SECOND WAVE WILL TRACK A TOUCH FARTHER
TO THE NORTHEAST AND WILL BE ASSOCIATED WITH THE WEAKENING SURFACE
LOW MOVING ACROSS WESTERN LAKE SUPERIOR MONDAY AFTERNOON. THERE HAS
DEFINITELY BEEN A SOUTHWEST TREND IN THE TRACK OF THESE WAVES OVER
THE LAST 24HRS...SO HAVE CONTINUED THAT TREND WITH THIS FORECAST.
WITH THE TRACK OF THE TWO WAVES...WILL SHOW INCREASING POPS OVER THE
WEST-SOUTHWEST HALF OF THE CWA OVERNIGHT TONIGHT (HIGHEST NEAR
IRONWOOD). BASED OFF THE TRACK OF THE SHORTWAVE AND BEST 850-500MB
WARM AIR ADVECTION AND Q-VECTOR CONVERGENCE...THINK THE BEST
PRECIPITATION WILL BE SOUTHWEST OF THE CWA BUT STILL SHOULD SEE 1-2
INCHES OF SNOW OVER THE WESTERN THIRD OF UPPER MICHIGAN THROUGH
MONDAY MORNING. THEN AS THE SECOND WAVE MOVES THROUGH LATE MONDAY
MORNING THROUGH EARLY EVENING...SHOULD SEE A MORE BROAD/LIGHT SNOW
SPREADING SOUTHEAST OVER THE MUCH OF THE REST OF THE CWA. ONCE
AGAIN...SNOWFALL AMOUNTS SHOULD BE LIGHT WITH THIS SECOND WAVE AND
GENERALLY UNDER AN INCH.

THERE IS ONE OTHER ITEM OF CONCERN WITH THIS CLIPPER SYSTEM...LAKE
EFFECT/ENHANCED SNOW OFF LAKE MICHIGAN. AS THE SOUTH-SOUTHEAST FLOW
DEVELOPS OVER THE LAKE LATE TONIGHT AND MONDAY MORNING...875MB TEMPS
ARE STILL HOVERING AROUND -12 TO -13C AND PROVIDING DECENT DELTA-T
VALUES OVER THE LAKE. MODELS ARE INDICATING THERE BEING ENOUGH DRY
AIR AND SUBSIDENCE IN PLACE MONDAY MORNING TO LIMIT SNOW
DEVELOPMENT...BUT AS THE DEEPER MOISTURE ARRIVES IN THE AFTERNOON
WITH THE SECOND WAVE SHOULD SEE THE SNOW DEVELOP. THERE IS A LITTLE
BIT OF A CONCERN IN THE SHEAR IN THE CLOUD LAYER (SOUTHEAST WINDS AT
THE SURFACE...SOUTH MID CLOUD...AND SOUTHWEST AT THE TOP OF THE
CLOUD)...WHICH COULD HELP LIMIT THE INTENSITY OF THE SNOW. BASED OFF
THE CONSISTENCY IN THE HIGHER RESOLUTION MODELS...DID TREND THE POPS
UP TO LIKELY-DEFINITE VALUES OVER DELTA/SCHOOLCRAFT COUNTIES (AND
EVEN WESTERN ALGER) TO HIGHLIGHT THAT LAKE EFFECT SNOW POTENTIAL.
CURRENTLY HAVE AMOUNTS IN THE 1-2 INCH RANGE...BUT THERE COULD BE A
NARROW BAND OF HIGHER AMOUNTS DEPENDING ON THE EXACT LOCATION OF
WHERE THINGS SETUP.

CLEARING INITIALLY OVER PARTS OF THE AREA WILL LEAD TO A QUICK FALL
IN TEMPS THIS EVENING BEFORE SOUTHERLY FLOW AND HIGH CLOUDS
DEVELOP/MOVE OVER THE AREA OVERNIGHT. WITH DEWPOINTS IN THE MID-
LOWER SINGLE DIGITS ABOVE ZERO IN AREAS THAT CLEARED...HAVE USED
THAT AS A STARTING POINT AND WENT WITH LOWS AROUND 4-7 DEGREES BELOW
THAT. IT SHOULD BE SHORT LIVED LOWS...AS TEMPERATURES SLOWLY RISE
FROM WEST TO EAST AS THE CLOUDS INCREASE. HIGHS ON MONDAY SHOULD BE
AROUND OR SLIGHTLY ABOVE NORMAL (20S).

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM EST SUN JAN 25 2015

EXPECT NO SIGNIFICANT PATTERN CHANGES THROUGH THE PERIOD...AS A
500MB TROUGH LINGERS ACROSS EASTERN CANADA AND MUCH OF THE EAST HALF
OF THE U.S. THE MAIN EXCEPTION WILL BE TUESDAY THROUGH WEDNESDAY AS
THE RIDGE ACROSS THE WEST MOVES ACROSS THE PLAINS AND GREAT LAKES
REGION. BY 00Z THURSDAY 850MB TEMPS SHOULD WARM TO -4 TO -1C
/WARMEST OFF THE 24/12Z ECMWF/. SFC TEMPS TOPPING OUT NEAR FREEZING
WILL BE THE RESULT WEDNESDAY AFTERNOON. THE WARM SPELL WILL BE SHORT
LIVED AS COLDER AIR SET UP OVER N CENTRAL CANADA SHIFTS SINKS ACROSS
HUDSON BAY ON FRIDAY...AND SURGE ACROSS ONTARIO AND INTO THE UPPER
GREAT LAKES FROM SATURDAY THROUGH THE START OF THE NEXT WORK WEEK.
THE EXACT TIMING...SATURDAY OR LATER SATURDAY NIGHT...IS STILL IN
QUESTION. THE 25/00Z IS A LITTLE SLOWER TO PUSH THE COLD AIR DOWN.
GIVEN THAT THIS IS OVER 150HRS OUT...WILL GO WITH A BLENDED SOLUTION
FOR NOW.

AS FOR SOME OF THE SPECIFICS...WE WILL START 12Z MONDAY WITH THE
NEXT LOW KNOCKING ON THE DOOR /SET UP ACROSS SE MANITOBA THROUGH N
MN/. THE CANADIAN AND ECMWF ARE ON THE SW END OF THE LOW TRACK
ENVELOPE...WHILE THE NAM AND GFS ARE FARTHER TO THE NE AND TRACK IT
OVER W LAKE SUPERIR BY 00Z TUESDAY. EITHER WAY THE ROUGHLY 150 MILE
DIFFERNECE IN PLACMENT OF THE LOW DOES MAKE A DIFFERENCE IN THE WIND
FIELDS...BUT BOTH INDICATE SNOW FOR WESTERN AND AT LEAST MOST OF
CENTRAL UPPER MI. THIS SW TREND IN THE BETTER FORCING OCCURRED WITH
THE LAST SIGNIFICANT CLIPPER SYSTEM TOO...SO WE WILL SEE IF THIS
CONTINUES. WILL KEEP THE LIKELY POPS IN THE W ONLY.

BEHIND THE LOW A SFC RIDGE WILL SLIDE ACROSS UPPER MI FROM THE
W...AS THE NEXT LOW ORGANIZES ACROSS THE PLAINS STATES
TUESDAY/WEDNESAY. EXPECT THIS LOW /EXTENDING FROM ND ALL THE WAY
THROUGH N TX AT 18Z WEDNESDAY TO PUSH ACROSS FAR S LAKE MI BY
DAYBREAK THURSDAY. THERE IS AMAZING CONSISTANCY WITH THE TRACK AND
STRENGTH OF THIS LOW FOR THIS 108HR FCST. THE INVERTED TROUGH WILL
EXTEND ALL THE WAY THROUGH N LAKE SUPERIOR 00-12Z THURSDAY. THIS
WILL BE THE FOCUS FOR SNOW...ASSISTED BY THE NEXT ELONGATED
SHORTWAVE SWINGING IN FROM THE NW. AT THIS POINT THE GFS IS HINTING
IN 3-5IN OF SNOW FROM 00Z THURSDAY THROUGH 00Z FRIDAY...BEFORE THE
INVERSION HEIGHTS START DROPPING BELOW 5KFT AS STRONG HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NW.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 715 PM EST SUN JAN 25 2015

WEAKENED NE FLOW HAS ALLOWED FOR CLEARING OF LAKE EFFECT CLOUDS AT
KCMX/KIWD THIS AFTERNOON INTO EARLY EVENING. EXPECT LAKE CLOUDS AND
SNOW SHOWERS TO DIMINISH AT KSAW AS WELL BY 02Z THIS EVENING LEADING
TO VFR CONDITIONS AT ALL TAF SITES THIS EVENING.

A CLIPPER SYSTEM DROPPING SE THROUGH SASKATCHEWAN AND SRN MANITOBA
WILL MOVE ACROSS THE AREA LATER TONIGHT. THIS WILL LEAD TO GRADUALLY
LOWERING CEILINGS AHEAD OF THE SYSTEM AND THEN SNOW MOVING IN AT KIWD
LATE TONIGHT AND KCMX/KSAW TOMORROW MORNING. THE IFR VISIBILITIES
WILL AFFECT KIWD LATE TONIGHT...KCMX TOWARDS MID MORNING WITH MVFR TO
IFR VSBYS AFFECTING KSAW BY EARLY MON AFTERNOON.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 244 PM EST SUN JAN 25 2015

A HIGH PRESSURE RIDGE MOVING ACROSS LAKE SUPERIOR WILL CONTINUE TO
WEAKEN WINDS THROUGH THE EVENING HOURS...BEFORE INCREASING OUT OF
THE SOUTH THROUGH THE REST OF THE NIGHT AHEAD OF A CLIPPER SYSTEM.
THIS CLIPPER SYSTEM WILL MOVE SOUTHEAST THROUGH NORTHWEST WISCONSIN
WHILE WEAKENING. THE SOUTHERLY FLOW AHEAD OF THE CLIPPER WILL LEAD
TO WINDS OF 20-30KTS LATE TONIGHT INTO MONDAY. A HIGH PRESSURE
RIDGE BUILDING INTO THE UPPER GREAT LAKES REGION ON MONDAY NIGHT
WILL DIMINISH WINDS BELOW 15KTS BY LATE MONDAY NIGHT AND WILL
REMAIN THROUGH TUESDAY. A LOW PRESSURE SYSTEM DEVELOPING IN THE
NORTHERN/CENTRAL PLAINS ON TUESDAY NIGHT WILL SHIFT EAST INTO THE
MID MISSISSIPPI VALLEY BY WEDNESDAY NIGHT...SHIFTING A TROUGH EAST
ACROSS THE UPPER GREAT LAKES REGION. WINDS ASSOCIATED WITH THIS
TROUGH WILL LIKELY STAY BELOW 25KTS.
&&

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

$$

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



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