Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 242033
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
433 PM EDT THU APR 24 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 432 PM EDT THU APR 24 2014

LOW PRESSURE TROUGH STRETCHES FROM SOUTHERN SASKATCHEWAN TO IOWA AND
NORTHERN MO. TWO MAIN AREAS OF LOW PRESSURE RESULT FROM SPLIT FLOW
ALOFT AND TWO SEPARATE SHORTWAVES. NORTHERN SHORTWAVE IS THE MAIN
DRIVER OF THE PRECIPITATION IMPACTING UPPER LAKES THIS AFTN AND
TONIGHT. WRAPPED UP SHORTWAVE MOVES ACROSS MINNESOTA THIS EVENING.
WARM AIR ADVECTION AHEAD OF SFC-H85 TROUGH AND INCREASING MOISTURE
WILL CONTINUE TO SUPPORT BATCH OF PRECIPITATION LIFTING ACROSS
WISCONSIN AND UPPER MICHIGAN. THUS FAR...BASED ON METAR 3HR PRECIP
REPORTS...HEAVIEST PRECIP IS OCCURRING OVER WESTERN WI COMPARED TO
EASTERN WI. THIS IS LIKELY DUE TO VERY DRY AIR BLO H7 SEEN ON 12Z
SOUNDING AT KAPX IN NORTHERN LOWER MICHIGAN. EXPECT HEAVIER PRECIP
TO REMAIN OVER WEST HALF OF CWA INTO THE EVENING AS MOISTURE
ADVECTION AT H85 COMBINES WITH INCREASING LARGER SCALE LIFT FROM
SHORTWAVE TROUGH/Q-VECTOR CONVERGENCE AT H85-H5 MOVING IN FROM THE
WEST. JET STREAK LIFTING NNE ACROSS THE AREA WILL ENHANCE DIFFLUENCE
ALOFT TO INCREASE PRECIP. FARTHER EAST...MOISTURE ADVECTION AND
ISENTROPIC ASCENT WILL BE THE MAIN INSTIGATOR FOR PRECIP...BUT THINK
THAT PRECIP OVER THE EAST WILL BE HINDERED BY THE DRY AIR FEEDING IN
FROM THE EAST.

PTYPE REMAINS MAIN ISSUE AND SNOW AMOUNTS. TOP DOWN LOOK AT
SOUNDINGS SHOW NOT MUCH WARM LAYER ALOFT...SO SNOW WILL BE FALLING
INTO THE LOWER LAYERS. QUESTION THEN IS HOW MUCH WARMING OCCURS IN
THE BLYR. THUS FAR...INTERIOR SECTIONS OVER WEST HALF OF CWA HAVE
SEEN RAIN/SNOW MIX BUT LOWER LEVEL ELEVATIONS ARE SEEING ONLY RAIN.
THINK THE MODELS ARE UNDERPLAYING THE EXTENT OF DRY AIR AND
ULTIMATELY THE EVAPORATIVE COOLING...SO AM KEEPING A MIX OF RAIN AND
SNOW IN OVER THE INTERIOR. ONCE THE HEAVIER PRECIP MOVES ACROSS THIS
EVENING...THINK THAT STRONGER DYNAMICS/LIFTING WILL RESULT IN MORE
EVAPORATIVE COOLING AND SWITCH MOST OF THE PRECIPITATION OVER TO
SNOW...ESPECIALLY OVER THE HIGHER TERRAIN OF NORTHWEST UPR MICHIGAN
AND NORTH CNTRL UPR MICHIGAN. OTHERWISE...SHOULD BE A RAIN/SNOW MIX
OVER WESTERN UPR MICHIGAN...WITH MAINLY RAIN FOR LOWER ELEVATIONS OF
CNTRL CWA AND ON ACROSS EASTERN SECTIONS...WHERE TEMPS THIS AFTN
HAVE REACHED UPR 40S TO NEAR 50 DEGREES IN SOME INTERIOR LOCATIONS.
ROAD TEMPS ALL OVER UPR MICHIGAN ARE IN THE 40S AND 50S...SO DO NOT
EXPECT MUCH SNOW ACCUMULATION ON ROADS INITIALLY...EVEN WITH HEAVIER
RATES. EVENTUALLY WITH COOLING THIS EVENING...SOME SLUSHY SNOW WILL
TRY TO ACCUMULATE ON ROADS OVER THE NORTHWEST CWA. MOST OF THE ACCUMS
THOUGH WILL BE ON THE GRASSY SURFACES. TWEAKED DOWN TOTAL SNOW
AMOUNTS TO 3 TO 5 INCHES AT THE MOST OVER HIGHER TERRAIN OF THE
KEWEENAW AND MORE IN THE 1 TO 4 INCH RANGE OVER HIGHER TERRAIN OF
WEST AND NCNTRL UPR MICHIGAN. SNOW WILL BE WET AND SLOPPY WITH SLR/S
BLO 10:1. NO CHANGES TO THE ADVY FOR THE KEWEENAW. GIVEN LESSER SNOW
AMOUNTS OVR REST OF CWA...WILL JUST MENTION IN THE HAZARDOUS WEATHER
OUTLOOK.

LATE TONIGHT INTO FRIDAY...SHORTWAVE LIFTS ACROSS UPR MICHIGAN.
BETTER MOISTURE TRANSPORT AT H85-H7 WRAPS BY TO THE EAST...LEAVING
LIMITED DEEPER MOISTURE FOR ALL BUT LK SUPERIOR AND THE KEWEENAW.
COULD SEE ANOTHER INCH OR SO IN THE MORNING OVER THE KEWEENAW...AS
LONG AS THIS PROGRESSIVE IDEA OFFERED UP BY THE MODELS DOES COME
TO FRUITION. SOUNDINGS BY EARLY AFTN FRIDAY...INDICATE SHALLOW
MOISTURE TO H9-H85 WITH ANOTHER SWATH OF DEEPER MOISTURE COMING BACK
IN DURING THE AFTN. BLYR WARMING WILL SWITCH ANY PRECIP TO RAIN BY
EARLY AFTN. MIXING TO H9 SUPPORTS TEMPS WARMING WELL INTO THE 40S
AND POSSIBLY AS WARM AS THE 50S OVER THE SCNTRL WITH WEST SFC WINDS
AND CLOUDS THINNING OUT MORE THAN ACROSS REST OF CWA.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 432 PM EDT THU APR 24 2014

FRI NIGHT...MODELS WERE CONSISTENT IN PLACING THE MID LEVEL LOW OVER
CNTRL/ERN LAKE SUPERIOR AT 00Z/SAT WHICH WOULD BRING THE BAND OF
700-500 MB QVECTOR CONV THROUGH THE ERN CWA DURING THE EVENING. THIS
SHOULD SUPPORT SOME ADDITIONAL PCPN THROUGH AT LEAST 03Z. LOW LEVEL
THERMAL PROFILES FAVOR MAINLY RAIN POSSIBLY MIXED WITH SOME SNOW.
OTHERWISE...LOW LEVEL CYCLONIC CONV FLOW WITH DEEPER MOISTURE
LINGERING OVER THE REGION WILL ALSO BRING SOME SNOW TO NORTHERN UPPER
MICHIGAN...MAINLY FOR AREAS FAVORED BY UPSLOPE NNE FLOW. ANY
ACCUMULATIONS SHOULD ONLY AMOUNT TO A HALF INCH OR LESS.

SAT...THERE MAY BE SOME LEFTOVER LIGHT SNOW INTO THE HIGHER TERRAIN
OF NORTH CENTRAL UPPER MICHIGAN THROUGH MID MORNING. OTHERWISE...SFC
HIGH PRES WILL BUILD OVER HUDSON BAY WITH A SFC RIDGE EXTENDING INTO
THE NRN LAKES UNDER STEADILY RISING HEIGHTS. THIS SHOULD BRING
DRYING BY AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES OVER THE CWA.
DESPITE THE RETURN OF AFTERNOON SUNSHINE...LOCATIONS DOWNSTREAM OF
ENE FLOW OFF OF LAKE SUPERIOR WILL REMAIN QUITE COLD WITH HIGH ONLY
IN THE UPPER 30S AND LOWER 40S WHILE LOCATIONS OVER THE SOUTH CLIMB
INTO THE MID AND UPPER 40S.

SAT NIGHT INTO MON...THE STRONG BLOCKING PATTERN DEVELOPING WITH THE
MID LEVEL HIGH NEAR HUDSON BAY AND LOW INTO THE CENTRAL PLAINS WILL
FAVOR DRY EASTERLY FLOW AROUND THE SFC HUDSON BAY HIGH. AS A
RESULT...THE DRIER LOOK OF THE ECMWF WAS FAVORED WHICH KEEPS THE
PCPN MAINLY TO THE SOUTH AND WEST OF UPPER MICHIGAN. THE GFS HAS
ALSO TRENDED TOWARD THIS SOLUTION. HOWEVER...SLIGHT TO LOWER END
CHANCE POPS OVER THE WEST AND SOUTH BY SUN NIGHT INTO MON...PER MODEL
CONSENSUS ARE NOT UNREASONABLE GIVEN LINGERING MODEL DIFFERENCES AND
UNCERTAINTY.

TUE-THU...THE MODELS ARE IN GENERAL AGREEMENT WITH THE LARGER SCALE
EVOLUTION OF THE PATTERN AS A REX BLOCK DEVELOPS WITH THE MID LEVEL
LOW FROM NEAR IA INTO THE SRN LAKES. WITH A SFC LOW MOVING TO NEAR
LOWER MI OR INDIANA...SFC MOISTURE INFLOW TOWARD THE NRN LAKES ALONG
WITH WEAK SHRTWVS ON THE NRN SIDE OF THE MID LEVEL CIRCULATION WOULD
SUPPORT INCREASING RAIN CHANCES FOR WED INTO THU. TEMPS SHOULD
REMAIN BELOW NORMAL...ESPECIALLY OVER THE NORTH WITH COLD NE FLOW
INTO THE AREA AND INCREASING CLOUDS BY WED-THU.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 144 PM EDT THU APR 24 2014

LIGHT RAIN AND SNOW GRADUALLY SPREADS ACROSS THE TERMINALS THIS
AFTERNOON. PRECIPITATION WILL CHANGE TO MAINLY SNOW BY LATE TODAY AT
CMX...BUT COULD STAY A MIX OF RAIN AND SNOW MUCH OF THE NIGHT AT IWD
AND SAW. EXPECT IFR TO MVFR CONDITIONS...FIRST COMING FROM THE VSBY
AND EVENTUALLY DUE TO LOWERING CIGS. THE MOST PERSISTENT LOWER
CONDITIONS ARE EXPECTED AT CMX TONIGHT WITH UPSLOPING EASTERLY
WINDS. LATE TONIGHT INTO FRIDAY MORNING...THE PRECIPITATION...MAINLY
IN THE FORM OF SNOW...DIMINISHES AT THE TAF SITES...BUT LOWER IFR
CIGS WILL REMAIN. EXPECT SLOW IMPROVEMENT TO MVFR CONDITIONS BY
FRIDAY AFTERNOON.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT THU APR 24 2014

AS THE HIGH PRESSURE RIDGE OVER LAKE HURON THIS AFTN DRIFTS OFF THE
EAST COAST FRIDAY MORNING...A LOW OVER THE NORTHERN PLAINS WILL
SHIFT TO THE LOWER GREAT LAKES. SE GUSTS WILL NEAR 30-35KTS LATE
THIS EVENING OVER MAINLY CENTRAL LAKE SUPERIOR. THE LOW WILL
CONTINUE INTO NEW ENGLAND ON SATURDAY. A LARGE CANADIAN HIGH
PRESSURE RIDGE WILL THEN BUILD ACROSS THE UPPER GREAT LAKES SATURDAY
AND REMAIN OVER THE REGION INTO MONDAY. ANOTHER ROUND OF STRONGER
EAST WINDS NEARING 25-30KTS WILL BE POSSIBLE MONDAY...IN BETWEEN
THE EXITING RIDGE OF HIGH PRESSURE AND NEARING LOW PRESSURE FROM THE
PLAINS STATES.
&&

.HYDROLOGY...
ISSUED AT 432 PM EDT THU APR 24 2014

RUNOFF FROM RECENT ABOVE NORMAL TEMPS AND SNOWMELT CONTINUES TO FLOW
THROUGH THE GROUND...SO SOME AREA STREAMS AND RIVERS ARE STILL RUNNING
HIGH AND EVEN RISING SLOWLY...DESPITE THE LOWER TEMPERATURES THAT
WERE OBSERVED RECENTLY. LOCATIONS THAT STILL ARE STILL NEAR OR ABOVE
BANKFULL AT THIS TIME INCLUDE THE STURGEON RIVER NEAR CHASSELL AND
THE PAINT RIVER NEAR CRYSTAL FALLS. WHILE THE PAINT RIVER NEAR
CRYSTAL FALLS IS NOT EXPECTED TO REACH FLOOD STAGE IN THE SHORT
TERM...THE STURGEON RIVER IS EXPECTED TO CREST AT FLOOD STAGE
TONIGHT AND FRIDAY AND HOLD STEADY INTO THE WEEKEND.

REPORTS INDICATE LITTLE ICE REMAINS ON AREA RIVERS...SO THE ICE JAM
FLOODING THREAT HAS GREATLY DIMINISHED. THE ONLY EXCEPTION MIGHT BE
AT THE MOUTHS OF RIVERS THAT FLOW INTO THE GREAT LAKES WHERE
SIGNIFICANT ICE REMAINS AT THE SHORE OR JUST OFFSHORE.

MORE PRECIPITATION WILL RETURN TONIGHT INTO FRIDAY AS ANOTHER LOW
PRESSURE SYSTEM MOVES FROM THE PLAINS TOWARD THE GREAT LAKES...
POTENTIALLY ADDING TO 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 0.50-1.25 INCH
OF LIQUID WILL BE POSSIBLE BY FRIDAY AFTERNOON. 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. IF MORE OF THE PRECIPITATION FALLS AS SNOW...RUNOFF WILL
BE DELAYED UNTIL WARMER WEATHER RETURNS NEXT WEEK.

OVERALL...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...
  WINTER WEATHER ADVISORY UNTIL 11 AM EDT FRIDAY FOR MIZ001-003.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...JLB
AVIATION...JLA
MARINE...JLA
HYDROLOGY...JLB






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