Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 230356
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1156 PM EDT TUE APR 22 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 416 PM EDT TUE APR 22 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF MOVING ONSHORE
ALONG THE W COAST OF THE CONUS. JUST DOWNSTREAM OF THE TROF...A
SHARP RIDGE ALIGNED ALONG THE LEE OF THE ROCKIES IS ALLOWING FOR
TROF AMPLIFICATION INTO THE GREAT LAKES...LED BY SHORTWAVE THAT WAS
PASSING JUST N OF LAKE SUPERIOR 24HRS AGO. PER 12Z RAOBS AND
LATEST RUC ANALYSIS...850MB THERMAL TROF IS CURRENTLY CENTERED OVER
CNTRL LAKE SUPERIOR/CNTRL UPPER MI. AS A RESULT...CLOUD COVER HAS
BEEN SLOW TO CLEAR THIS AFTN. TRAILING SHORTWAVE THAT IS CURRENTLY
DROPPING SE THRU WRN UPPER MI/NRN LAKE MICHIGAN IS ALSO AIDING THE
CLOUD COVER AND HAS ALSO GENERATED FLURRIES/-SHSN THIS AFTN.
FLURRIES/-SHSN HAVE ENDED ON THE KEWEENAW AND WILL QUICKLY EXIT THE
REST OF THE FCST AREA IN THE NEXT 2-3HRS. AS WOULD BE EXPECTED UNDER
THE THERMAL TROF AND WITH ABUNDANT CLOUD COVER...TEMPS HAVE STUGGLED
TO RISE TODAY. MID AFTN READINGS ARE IN THE 30S ACROSS MUCH OF UPPER
MI (LOW 30S AT SOME LOCATIONS) TO THE LOW/MID 40S SCNTRL AND NEAR
KIWD.

CLEARING IS NOW GETTING UNDERWAY ACROSS LAKE SUPERIOR...ESPECIALLY
THE W HALF. SKIES WILL CLEAR ACROSS THE BOARD DURING THE EVENING AS
MUCH DRIER AIR CONTINUES TO SPREAD INTO THE AREA FROM THE N AND
W...BUT CLOUDS WILL HANG ON LONGEST OVER THE E AS THERE IS STILL AN
AXIS OF MOISTURE/CLOUDS EXTENDING BACK TOWARD LAKE NIPIGON. AFTER A
CHILLY DAY...CLEAR SKIES WITH WINDS DIMINISHING TO LIGHT/CALM AS SFC
HIGH PRES RIDGE AXIS SETTLES OVER WRN UPPER MI DURING THE NIGHT WILL
SET THE STAGE FOR A COLD NIGHT. DRY AIR MASS WITH PRECIPITABLE WATER
IN THE 40-50PCT RANGE WILL ENHANCE RADIATIONAL COOLING. WILL GO AT
OR BLO LOWEST GUIDANCE...ESPECIALLY WHERE MEANINGFUL SNOWCOVER STILL
EXITS. TRADIATIONAL COLDS SPOTS WILL LIKELY FALL INTO THE TEENS...
BUT 20S WILL GENERALLY BE THE RULE. RECORD LOW FOR NWS MQT FOR APR
23 IS 17F. MIGHT BE CLOSE TO THAT.

ON WED...ABUNDANT SUNSHINE TO START THE DAY WILL GIVE WAY TO
INCREASING HIGH CLOUDS FROM THE W. WITH SFC HIGH PRES RIDGE JUST
DRIFTING E...MESOHIGH WILL SET UP OVER CNTRL AND ERN LAKE SUPERIOR
DURING THE AFTN AND ALSO OVER LAKE MICHIGAN. AS A RESULT...LAKE
BREEZES WILL DOMINATE...KEEPING LAKESIDE LOCATIONS CHILLY...PROBABLY
30S FOR MUCH OF THE DAY. DRY AIR MASS WILL AID DEEP MIXING
POTENTIAL...SO AREAS WELL INLAND FROM THE LAKES WILL BE ABLE TO WARM
NICELY AFTER THE COLD START. MIXING TO AROUND 800MB ON FCST
SOUNDINGS SUGGESTS MAX TEMPS INTO THE MID 50S ALONG THE WI BORDER.
WILL BE WARMER IF MIXING IS HIGHER. MIXING WILL ALSO RESULT IN DWPTS
FALLING DURING THE AFTN. UTILIZED SOME OF THE DRYING POTENTIAL BASED
ON MIXING HEIGHT TO LOWER DWPTS TO JUST UNDER 20F IN THE INTERIOR.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 447 PM EDT TUE APR 22 2014

THE BULK OF THE LONG TERM FORECAST DEALS WITH AN UPPER LEVEL TROUGH
AND ASSOCIATED LOW PRESSURE SYSTEM THAT MOVES THROUGH THE GREAT
LAKES REGION LATE WEDNESDAY NIGHT AND LIKELY CONTINUING INTO
FRIDAY EVENING. THE UPPER TROUGH MOVING OVER THE WESTERN COAST OF
THE PACIFIC NORTHWEST WILL BE THE FEATURE TO INFLUENCE THE AREA FOR
THE END OF THIS WEEK. AS THIS SYSTEM CROSSES THE ROCKIES...A
SURFACE LOW WILL DEVELOP IN THE LEE OF THE CANADIAN/NORTHERN
ROCKIES AND SHIFT EAST INTO THE UPPER MISSISSIPPI VALLEY ON
THURSDAY. HIGH PRESSURE THAT WILL BE OVER THE AREA TONIGHT AND
WEDNESDAY WILL BE SLOWLY DEPARTING THE AREA WEDNESDAY NIGHT.
THIS...COMBINED WITH A SLIGHTLY LATER ARRIVAL FROM THE UPPER
TROUGH...WILL DELAY THE START OF THE PRECIPITATION LATER THAN
EXPECTED 24 HOURS AGO AND GENERALLY MOVING IN DURING THE DAY ON
THURSDAY. THERE ARE SEVERAL WAVES ASSOCIATED WITH THIS UPPER
TROUGH...WHICH LEADS TO A DOUBLE BARREL LOW MOVING OUT OF THE
NORTHERN/CENTRAL PLAINS ON WEDNESDAY NIGHT. WHILE PREVIOUS MODELS
RUNS HAD THE IDEA OF THESE LOWS MERGING WHEN THE NORTHERN/SOUTHERN
WAVES IN THE UPPER TROUGH COMING TOGETHER AND STRENGTHENING AS IT
MOVES THROUGH NORTHERN LAKE MICHIGAN. BUT MOST OF THE 12Z MODEL
RUNS (EXCEPT FOR THE GFS) HAS TRENDED TOWARDS THE LACK OF PHASING
BETWEEN THOSE UPPER LEVEL WAVES. WITHOUT THIS PHASING...THE
SOUTHERN STREAM WAVE WOULD SHIFT EAST THROUGH THE CENTRAL
MISSISSIPPI VALLEY THURSDAY NIGHT AND JUST HAVE A BROAD LOW MOVING
THROUGH THE AREA. WHILE THIS STILL BRING PRECIPITATION TO THE
AREA...IT MAY HAVE SOME AFFECT ON THE AMOUNTS OVER PORTIONS OF THE
AREA BEFORE THE NORTHERN STREAM WAVE ARRIVES THURSDAY NIGHT OVER
THE UPPER GREAT LAKES. THE GREATEST AFFECT OF THIS SPLIT FEATURE IS
FOR THE PRECIPITATION TO STEADILY SHIFT NORTHEAST AND GENERALLY OUT
OF THE AREA FOR FRIDAY. IF THIS IS THE CASE...FLOW ALOFT WILL BE
MORE WESTERLY ON FRIDAY...LEADING TO WARMER TEMPERATURES AND
DRIER CONDITIONS THAN INITIALLY EXPECTED.

ALTHOUGH THERE ARE STILL DIFFERENCES IN THE MODELS WITH THE EXACT
HANDLING OF THE PHASING...IT STILL APPEARS THE MOST OF THE CWA WILL
SEE 0.5 INCH OF QPF. THE HEAVIEST PRECIPITATION STILL APPEARS TO
OCCUR OVER THE WESTERN HALF TO 2/3RDS OF THE U.P. AND EXPECT SOME
LOCATIONS OVER THE WEST TO BE NEARING 1 INCH OF LIQUID EQUIVALENT.
THE IMPACT FROM THIS EVENT AND THE ASSOCIATED 0.75-1.0 INCH OF QPF
OVER THE WESTERN HALF OF THE CWA WILL DEPEND ON THE PRECIP TYPE
FORECAST. ALTHOUGH THIS FORECAST HAS BEEN AND CONTINUES TO BE
TRICKY...TRENDS IN THE MODELS ARE POINTING TOWARDS SNOW OVER AT
LEAST THE NORTHWEST HALF OF UPPER MICHIGAN WITH THE WARMER AIR
REMAINING HUNG UP TO THE SOUTH-SOUTHEAST OF THE AREA. IN
ADDITION...WITH THE DRY AIR FROM THE HIGH TAKING LONGER TO
DEPART...THE LOW LEVEL DRY AIR WILL AID EVAPORATIVE COOLING IN THE
LOW LEVELS AS THE PRECIPITATION STARTS. THIS WOULD LEAD TO ABOVE
FREEZING LAYERS ABOVE THE SURFACE TO COOL TO OR BELOW FREEZING AND
HAVE A FEELING THE PRECIP TYPE WILL BE LARGELY SNOW INITIALLY OVER
THE WEST (ESPECIALLY HIGHER TERRAIN). THE 12Z MODEL THERMAL
FIELDS ARE STILL BORDERLINE FOR PRECIP TYPE HEADING THROUGH
THURSDAY...BUT LOOKING AT SOUNDINGS THERE IS A NEARLY ISOTHERMAL
LAYER BELOW 750MB AROUND OR BELOW FREEZING. THUS...HAVE TRENDED THE
FORECAST TOWARDS A MORE SNOW THAN RAIN OVER THE NORTHWEST HALF.
AT THIS TIME...THAT BEST OPPORTUNITY FOR A RAIN/SNOW MIX OR MORE
RAIN WOULD BE ALONG THE WISCONSIN BORDER AND ALSO SOUTHEAST OF A
LINE FROM IRON MOUNTAIN TO GWINN TO SENEY.

ALTHOUGH THERE ARE SOME INDICATIONS IN THE COBB OUTPUT OF HIGHER
SNOW RATIOS...WOULD EXPECT VALUES TO BE GENERALLY IN THE 8-10 TO 1
RANGE DUE TO THE AMOUNT OF FORCING BELOW THE DGZ. SINCE THE SNOW
WILL START DURING THE DAY THURSDAY...IT IS DIFFICULT TO GET
SIGNIFICANT ACCUMULATIONS TO OCCUR BEFORE DAYTIME HEATING IS LOST
(ESPECIALLY ON ROADWAYS) AND HAVE LIMITED AMOUNTS DURING THE DAY TO
A SLUSHY COUPLE INCHES OVER PORTIONS OF THE WEST. WITH THE COOLING
AT NIGHT...SHOULD SEE ACCUMULATIONS INCREASE ON BOTH ROADS AND
SNOW/GRASS COVERED SURFACES. AT THAT TIME...THE BEST QPF AND COLD
AIR WILL BE OVER LAKE SUPERIOR AND AFFECTING THE KEWEENAW PENINSULA.
HAVE THE HIGHEST AMOUNTS FORECASTED FOR THE KEWEENAW...WITH 6-9
INCHES BY 12Z FRIDAY. SOUTH AND EAST OF THERE ARE MORE UP IN THE AIR
WITH THE RAIN POTENTIAL AND SLIGHTLY WARMER SURFACE
TEMPERATURES...BUT STILL FEEL THERE COULD BE 2-6 INCHES OF SLUSHY
ACCUMULATION. LOOKING AT THE 00Z ECMWF ENSEMBLE SNOWFALL...MORE THAN
50 PERCENT OF THE MEMBERS HAVE 24HR SNOWFALL AMOUNTS OF EXCEEDING 3
INCHES OVER THE NORTHWEST 2/3RDS OF THE CWA AND PROBS DECREASE TO
20-30 PERCENT OF 6 INCHES.

WITH LOW CONFIDENCE ON WARNING AMOUNTS AT THIS POINT (AND THE
IMPACTS ARE LARGELY IN THE 5TH PERIOD)...DIDN/T FEEL COMFORTABLE
WITH ISSUING A WATCH AT THIS PERIOD. THEREFORE...HAVE ISSUED AN SPS
FOR PORTIONS OF WESTERN UPPER MICHIGAN AND WILL ALLOW THE SHIFT
TONIGHT TO SEE IF THE TRENDS FROM THE 12Z RUNS CONTINUE.

BEHIND THE SYSTEM...MODELS ARE FAIRLY CONSISTENT ON A STRONG
CANADIAN HIGH DEVELOPING IN THE PRAIRIES AND SHIFTING EAST TO
HUDSON BAY EARLY NEXT WEEK. THAT WILL LEAD TO DRY
NORTH-NORTHEASTERLY FLOW OVER THE AREA INTO THE FIRST HALF OF NEXT
WEEK. THAT FLOW REGIME SHOULD KEEP TEMPERATURES BELOW NORMAL
(POTENTIALLY NEARING RECORD LOW HIGH TEMPS AT OUR OFFICE) AND ANY
PRECIP ASSOCIATED WITH THE UPPER TROUGH MOVING THROUGH THE
CENTRAL/SOUTHERN PLAINS SOUTH OF THE AREA.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1156 PM EDT TUE APR 22 2014

HIGH PRES AND ITS ASSOCIATED DRY AIRMASS WILL DOMINATE THROUGH THE
PERIOD RESULTING IN LIGHT WINDS AND VFR CONDITIONS AT ALL TERMINALS.
THERE WILL BE SOME INCREASE IN MID CLOUDS AT KIWD LATE IN THE PERIOD
AS ANOTHER LOW PRES SYSTEM ADVANCES FROM THE PLAINS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EDT TUE APR 22 2014

AS HIGH PRES RIDGE EXTENDING FROM MN SOUTHWARD SHIFTS TO WRN LAKE
SUPERIOR/WRN UPPER MI TONIGHT...WINDS WILL CONTINUE TO DIMINISH FROM W
TO E. WINDS ARE ALREADY LIGHT OVER THE WRN LAKE...AND THE INITIAL NW
20-30KT WINDS OVER ERN LAKE SUPERIOR WILL DROP TO UNDER 15KT
TONIGHT. LIGHT WINDS WILL LINGER THRU WED AS HIGH PRES RIDGE SLOWLY
DRIFTS E. HOWEVER...E WINDS WILL BEGIN TO INCREASE TOWARD 20KT OVER
FAR WRN LAKE SUPERIOR IN THE AFTN. EASTERLY WINDS WILL THEN
GRADUALLY INCREASE WED NIGHT AND WILL REACH 20-30KT ACROSS MUCH OF
LAKE SUPERIOR THU IN ADVANCE OF LOW PRES APPROACHING THE WRN GREAT
LAKES. DEPENDING ON THE EXACT TRACK AND INTENSITY OF THE LOW...NOT
OUT OF THE QUESTION THAT THERE COULD BE SOME GALE FORCE WINDS OVER
WESTERN LAKE SUPERIOR WHERE TERRAIN FUNNELING/COASTAL CONVERGENCE
WOULD ENHANCE THIS E WIND. AS THE LOW SHIFTS TO THE E LATER ON FRI
INTO SAT AHEAD OF HIGH PRES BUILDING INTO SCENTRAL CANADA...THE WIND
WILL SHIFT TO THE N AND SLOWLY DIMINISH WITH THE CLOSER APPROACH OF
THE HIGH ON SAT. BEST CHANCE FOR SOME GALES FRI INTO EARLY SAT WOULD
BE OVER THE E HALF OF THE LAKE...AGAIN...DEPENDING ON INTENSITY OF
THE LOW.
&&

.HYDROLOGY...
ISSUED AT 458 PM EDT TUE APR 22 2014

A MUCH COLDER DAY SEEN ACROSS UPPER MICHIGAN TODAY WHEN
COMPARED TO YESTERDAY. THIS HAS LED TO REDUCED SNOWMELT WHICH
WILL CONTINUE INTO WEDNESDAY...ALTHOUGH SOME RIVER LEVELS WILL
LIKELY STILL BE ON THE RISE AS WATER WORKS THROUGH THE RIVER
SYSTEMS. ALTHOUGH RATHER COOL TEMPERATURES WILL REMAIN...UNSETTLED
WEATHER WILL RETURN THURSDAY AND THURSDAY NIGHT...POTENTIALLY ADDING
TO THE RUNOFF. AT THIS POINT THE BEST CHANCE OF SIGNIFICANT
PRECIPITATION LOOKS TO BE OVER THE WEST HALF OF UPPER MI...AND
SPECIFICALLY THE KEWEENAW PENINSULA...WHERE 0.50-1.00 INCH OF LIQUID
WILL BE POSSIBLE BY FRIDAY MORNING. THERE IS SOME UNCERTAINTY ON
HOW MUCH WILL FALL AS RAIN AND HOW MUCH WILL FALL AS SNOW...BUT THE
BEST CHANCE OF SNOW WILL BE OVER THE KEWEENAW PENINSULA. WE WILL
CONTINUE TO REFINE THE FCST AS THE TIME NEARS.

SO FAR THE LOCATIONS EXPERIENCING RISES NEAR OR ABOVE BANKFULL HAVE
BEEN ALSTON/ALSM4/ AND CHASSELL/CLLM4/ ON THE STURGEON
RIVER AND CRYSTAL FALLS/CRYM4/ ON THE PAINT RIVER. SINCE SNOW
MELT THE NEXT FEW DAYS WILL BE DIMINISHING...EXPECT THE RIVERS TO
SLOWLY SUBSIDE AND NOT EXCEED FLOOD STAGE. OTHERWISE...WIDESPREAD
FLOODING IS NOT FORESEEN AT THIS TIME. THOSE LIVING AROUND
RIVERS...CREEKS...AND STREAMS SHOULD MONITOR RIVER LEVELS OVER THE
NEXT WEEK.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...VOSS
MARINE...ROLFSON
HYDROLOGY...SRF






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