Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 180903
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
403 AM EST THU DEC 18 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EST THU DEC 18 2014

AN UPPER RIDGE STRETCHING FROM MINNESOTA THROUGH NORTHWEST ONTARIO
WILL BE THE MAIN FEATURE CONTROLLING THE WEATHER OVER THE UPPER
GREAT LAKES REGION OVER THE NEXT 24 HOURS. BENEATH THIS UPPER
RIDGE...A 1029MB SURFACE HIGH SITS JUST TO THE NORTH OF THE
MINNESOTA WHILE THE SURFACE TROUGH THAT LED TO THE SNOW YESTERDAY
IS OVER NORTHERN LAKE MICHIGAN AND NORTHERN LOWER MICHIGAN AND
WEAKENING. NORTH-NORTHEASTERLY FLOW AROUND THIS HIGH HAS PULLED
DRIER AIR INTO THE UPPER GREAT LAKES REGION...LEADING TO CLEARING
SKIES THIS PAST EVENING OVER MUCH OF LAKE SUPERIOR. BUT MOISTURE
TRAPPED BELOW THE SUBSIDENCE INVERSION...AND COMBINED WITH UPSLOPE
FLOW...HAS LED TO LOW CLOUDS PERSISTING OVER A GOOD PORTION OF
UPPER MICHIGAN EARLY THIS MORNING. THERE ARE A COUPLE SPOTS WHERE
THE CLOUDS DID CLEAR OUT...GENERALLY OVER THE KEWEENAW PENINSULA
AND ALSO IT/S STARTING TO OVER THE EAST. WHERE SKIES CLEARED
OUT...3AM TEMPERATURES ARE IN THE SINGLE DIGITS ABOVE ZERO (6
DEGREES AT KCMX)...WHILE THE CLOUDS HAVE KEPT THE TEMPERATURES IN
THE UPPER TEENS AND LOWER 20S ELSEWHERE. STILL SEEING LIGHT
FLURRIES HERE AT OUR OFFICE AT 330AM...SO WILL CONTINUE TO MENTION
ISOLATED FLURRIES IN THE FORECAST FOR THE UPSLOPE LOCATIONS THROUGH
DAYBREAK.

WITH THE UPPER RIDGE AND SURFACE HIGH MOVING OVER THE AREA
TODAY...EXPECT CONTINUED QUIET CONDITIONS FOR THE SHORT TERM
PERIOD. THERE ARE TWO AREAS OF FOCUS IN THE SHORT TERM
PERIOD...FIRST THE LOW CLOUDS AND THEIR DIMINISHMENT AND THEN THE
POTENTIAL FOR SOME FREEZING FOG OVERNIGHT TONIGHT. FOR THE LOW
CLOUDS...KMQT VWP INDICATES CLOUD TOPS AROUND 2.5KFT...WHICH
MATCHES UP WELL WITH THE INVERSION INDICATED ON THE MODELS AT
900MB. THE BIG QUESTION IS WHEN WILL THEY DISSIPATE TODAY. AT
THIS TIME OF THE YEAR WITH THE LOW SUN ANGLE AND LIMITED
MIXING...THERE IS LITTLE DAY TIME HELP AND WILL NEED TO RELY ON THE
ADVECTION OF DRIER AIR INTO THE AREA. UNFORTUNATELY...THIS IS WHERE
THE MODELS TEND TO DIFFER. THE 00Z NAM HOLDS ONTO THE CLOUDS FOR
MUCH OF THE DAY AND EVEN THROUGH THE NIGHT TONIGHT...BUT THINK THAT
IS LARGELY TIED TO IT TRADITIONALLY OVER DOING LOW LEVEL MOISTURE.
THAT APPEARS TO THE CASE EARLY THIS MORNING...WHERE IT HAS THE LOW
CLOUDS JUST TO THE WEST OF JAMES BAY BEING MUCH FARTHER TO THE
SOUTH AND SUPPOSEDLY ENTERING NORTHERN LAKE SUPERIOR AT THIS TIME.
THE RECENT RAP (ALONG WITH THE HRRR) RUNS ALSO HOLD ONTO THE CLOUDS
FOR MUCH OF THE DAY BEFORE CLEARING THEM OUT THIS AFTERNOON...BUT IT
APPEARS TO HAVE THE LOW LEVEL MOISTURE FARTHER NORTH OVER LAKE
SUPERIOR THAN WHAT IS ACTUALLY OCCURRING. THE MORE OPTIMISTIC
RUNS...WHICH SEEM TO HAVE A BETTER HANDLE ON THE LOCATION OF THE
LOW CLOUDS ARE THE 00Z GFS/ECMWF. THEY HOLD ONTO THE LOW CLOUDS
OVER THE NORTH CENTRAL AND WEST FOR THE FIRST PART OF THE MORNING
AND THEN SCATTER THEM OUT THROUGH THE LATER PART OF THE MORNING AND
EARLY AFTERNOON. WILL FOLLOW THAT IDEA AT THIS POINT FOR THE CLOUD
COVER FORECAST FOR TODAY. MEANWHILE OVER THE EAST...THE ADVECTION
OF THE DRIER AIR AND LITTLE UPSLOPE HELP SHOULD ALLOW THE LOW
CLOUDS TO DISSIPATE DURING THE FIRST PART OF THE MORNING. THAT DRY
AIR HAS ALREADY SCATTERED THE CLOUDS OUT OVER LUCE COUNTY AND
STARTING TO SEE IT WORK INTO ALGER/SCHOOLCRAFT COUNTIES. AS FOR
HIGHS TODAY...EXPECT THEM TO BE IN THE MID-UPPER 20S OVER MUCH OF
THE AREA.

FOLLOWING THE IDEA OF THE CLOUDS DIMINISHING TODAY...WOULD EXPECT A
VERY GOOD RADIATIONAL COOLING NIGHT TONIGHT UNDER THE CENTER OF THE
HIGH. THUS...WILL CONTINUE THE IDEA OF GOING AT OR BELOW THE
COLDEST GUIDANCE. THE GEM MODELS USUALLY PERFORM WELL IN
RADIATIONAL COOLING NIGHTS AND THEY HAVE LOWS IN THE LOWER SINGLE
DIGITS WHERE THEY ARE NOT INDICATING CLOUDS (ALTHOUGH THE REGIONAL
GEM REDEVELOPS LOW CLOUDS OVER THE HIGHER TERRAIN OF THE NORTH
CENTRAL TONIGHT). THUS...HAVE LOWS IN THE SINGLE DIGITS ABOVE ZERO
TO AROUND ZERO OVER THE INTERIOR LOCATIONS. WITH KCMX DROPPING TO 6
DEGREES AT 3AM THIS MORNING...THAT SUPPORTS TO EXPECTATIONS FOR
TONIGHT. THIS EXPECTED DROP IN TEMPS WILL LEAD TO THE POTENTIAL FOR
PATCHY FREEZING FOG OR AT LEAST SOME SOLID FROST. WITH DEWPOINTS IN
THE MID-UPPER TEENS TODAY...TEMPS SHOULD EASILY DROP THROUGH THOSE
VALUES THIS EVENING. DEWPOINTS THIS PAST EVENING AT KCMX WERE
SIMILAR TO WHAT IS EXPECTED ACROSS THE REST OF THE AREA THIS
AFTERNOON. WITH THEIR QUICK TEMP DROP AND LIGHT WINDS...THEY HAVEN/T
EXPERIENCED ANY FOG AT THIS POINT...BUT THE ICE ACCRETION ALGORITHM
DID INDICATE SOME ICE ACCUMULATION. THIS IS LIKELY DUE TO THAT QUICK
DROP AND IN TURN SOME QUICK/HARD FROST ON THE SENSOR. IT WILL BE
INTERESTING TO SEE IF ANY VERY SHALLOW FOG DEVELOPS AT KCMX OVER
THE NEXT COUPLE HOURS...AS IT WILL FORESHADOW WHAT WILL OCCUR
TONIGHT.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 354 PM EST WED DEC 17 2014

QUIET WEATHER IS EXPECTED THROUGH THE WEEKEND BEFORE AN ACTIVE
PATTERN DEVELOPS ACROSS THE GREAT LAKES REGION NEXT WEEK. THIS
INCLUDES THE POTENTIAL FOR A DISRUPTIVE SYSTEM LATE TUESDAY INTO
CHRISTMAS DAY.

THURSDAY NIGHT THROUGH SUNDAY...MID-LEVEL RIDGING STRETCHING FROM
THE NORTHERN PLAINS INTO NORTH-CENTRAL CANADA TODAY WILL BE DRIFTING
EASTWARD ACROSS THE UPPER GREAT LAKES AT THE BEGINNING OF THE
PERIOD. THE ASSOCIATED SFC RIDGE AXIS IS FORECAST TO BE OVER UPPER
MI THURSDAY NIGHT...SETTING THE STAGE FOR A RATHER CHILLY NIGHT.
DRIER AIR FILTERING IN FROM THE NORTH ON THURSDAY WILL SLOWLY ERODE
CLOUDS TRAPPED UNDER A 1-2KFT INVERSION. VEERING SFC WINDS MAY BRING
LOW CLOUDS BACK INTO THE AREA...BUT NOT UNTIL LATER THURSDAY NIGHT.
WITH A RELATIVELY FRESH SNOW PACK AND LIGHT WINDS...TEMPS LOOK TO
FALL TO NEAR ZERO FOR INTERIOR LOCATIONS TO THE MID TEENS FOR
SHORELINE LOCATIONS. WENT BELOW NEARLY ALL GUIDANCE. FREEZING FOG
WILL BE A POSSIBILITY FOR THE WEST AND CENTRAL INTERIOR FROM THE
GOOD RADIATIONAL COOLING AND RESIDUAL SFC MOISTURE UNDER THE
SHALLOW INVERSION.

AFTER A MOSTLY SUNNY DAY FOR AT LEAST THE EAST HALF ON
FRIDAY...CLOUDS WILL GRADUALLY INCREASE FROM THE WEST AS A WEAK
SHORTWAVE TROUGH ALONG THE U.S./CANADIAN BORDER MOVES TOWARD THE
UPPER GREAT LAKES. WITH LITTLE FORCING AND ONLY MODEST
MOISTURE...ONLY CLOUDS ARE EXPECTED FOR SATURDAY AND SUNDAY.

SUNDAY NIGHT THROUGH WEDNESDAY...A RATHER EXTENDED PERIOD OF
UNSETTLED WEATHER IS EXPECTED TO BEGIN BY THIS POINT. A SECONDARY
TROUGH DIGGING INTO THE NORTHERN HIGH PLAINS ON SATURDAY WILL
REINFORCE THE DECAYING LEAD TROUGH OVER THE UPPER MS VALLEY BY
SUNDAY AFTERNOON. LOW-LEVEL WAA AND FGEN COMBINED WITH DEEPER
MOISTURE AND MID-LEVEL FORCING WILL BE ENOUGH TO INDUCE SOME LIGHT
PRECIP ACROSS THE CWA LATE SUNDAY AFTERNOON INTO MONDAY. THERE IS
SOME DIFFERENCE ON HOW THE MODELS HANDLE THE PHASING OF THE TROUGHS
AT THIS POINT...WITH THE 12Z GFS SHOWING A SOMEWHAT STRONGER
SOLUTION. EITHER WAY...DEEPER MOISTURE WILL BE ADVECTING INTO THE
REGION...BUT WILL BE LESS THAN IDEAL FOR WIDESPREAD PRECIP. WILL
KEEP THE CONSENSUS BLEND OF CHANCE POPS FOR MUCH OF THE CWA LATE
SUNDAY AFTERNOON THROUGH MONDAY.

A LOT OF UNCERTAINTY GETS INFUSED INTO THE FORECAST BEGINNING MONDAY
NIGHT AS A THIRD...QUICK-MOVING...SHORTWAVE TRACKS ESE OUT OF THE
PACIFIC NW. HOW THIS TROUGH INTERACTS WITH THE EXISTING TROUGHS OVER
THE UPPER GREAT LAKES IS RATHER UNCLEAR AT THIS TIME. HOWEVER...THE
CONGLOMERATION OF THE TROUGHS WILL INDUCE A STRONG SFC LOW OVER THE
REGION BY CHRISTMAS EVE. BOTH THE ECMWF AND GFS ARE ADVERTISING A
LOW AS DEEP AS 960MB OVER LAKE HURON WEDNESDAY EVENING.

WHILE WIDESPREAD SNOW LOOKS FAIRLY CERTAIN MONDAY NIGHT INTO
CHRISTMAS...THE INTENSITY WILL REMAIN IN QUESTION FOR SOME TIME AS
GUIDANCE IS MIXED ON HOW THE SYNOPTIC PRECIP PATTERNS EVOLVE. ALL
THE LONG RANGE MODELS BRING ENERGY FROM THE FIRST TWO SHORTWAVES
NORTHEASTWARD ACROSS THE REGION LATE MONDAY NIGHT INTO TUESDAY. THIS
WOULD RESULT IN A QUICK ROUND OF MODERATE WET SNOW DURING THAT TIME
PERIOD.

TUESDAY NIGHT INTO WEDNESDAY MORNING MAY HAVE A BRIEF LULL IN PRECIP
BEFORE THE RAPIDLY DEEPENING LOW QUICKLY MOVES NORTHWARD OUT OF THE
OHIO VALLEY. THIS WOULD BRING INCREASING CHANCES OF MODERATE TO
HEAVY SNOW BY WEDNESDAY NIGHT. HOWEVER...LOW-LEVEL CAA WILL LAG THE
MAIN SYNOPTIC MOISTURE...REDUCING LAKE-ENHANCEMENT. EITHER WAY...A
1030MB HIGH PUSHING IN ON THE BACKSIDE OF THE LOW WILL RESULT IN
STRONG N/NNW WINDS BEGINNING WEDNESDAY AFTERNOON. WITH LAKE
EFFECT KICKING IN AS COLDER AIR FINALLY ARRIVES...CONDITIONS COULD
BE QUITE POOR FOR TRAVEL CHRISTMAS DAY.

SIMPLY PUT...THE SYSTEM LOOKS LIKE A DRAWN-OUT MESS FOR THE UPPER
GREAT LAKES TUESDAY INTO CHRISTMAS. STAYED TUNED...AS PLENTY OF
FORECAST CHANGES WILL LIKELY OCCUR OVER THE NEXT SEVERAL DAYS.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1224 AM EST THU DEC 18 2014

SKIES HAVE ALREADY CLEARED OUT AT KCMX AS DRY AIR ARRIVES FROM THE
NORTH. LINGERING FLURRIES WILL END EARLY THIS MORNING AT KIWD AND
KSAW...BUT LOW MVFR CIGS SHOULD REMAIN AS MOISTURE IS TRAPPED BELOW
STRENGTHENING INVERSION. EXPECT SKIES TO GRADUALLY CLEAR AT BOTH
SITES BY THIS AFTERNOON DUE TO MIXING OUT OF THE SHALLOW MOIST
LAYER. RISK OF FREEZING FOG TONIGHT AT MAINLY KSAW AND POSSIBLY
KCMX. DID LEAVE OUT OF TAFS ATTM THOUGH AS GREATEST CHANCE OF VSBY
REDUCTION AND ICE DEPOSITION SHOULD NOT OCCUR UNTIL AFTER END OF TAF
PERIOD LATER ON THURSDAY NIGHT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 AM EST THU DEC 18 2014

HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT WILL DIMINISH THE NORTHERLY WINDS BELOW 15KTS. THE HIGH
WILL BEGIN TO SHIFT TO THE EAST OF THE REGION ON FRIDAY AND ALLOW
WINDS TO GRADUALLY TURN TO THE SOUTH THROUGH FRIDAY NIGHT. A NEARLY
STATIONARY TROUGH IN THE LEE OF THE NORTHERN ROCKIES THIS WEEKEND
WILL KEEP THE SOUTH TO SOUTHWESTERLY WINDS IN PLACE AND GENERALLY
UNDER 20KTS. THIS TROUGH WILL GIVE WAY TO A DEVELOPING LOW THAT
WILL MOVE INTO THE NORTHERN PLAINS SUNDAY NIGHT AND THE UPPER
MISSISSIPPI VALLEY ON MONDAY.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KLUBER
AVIATION...JLA
MARINE...SRF





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