Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 230844
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
444 AM EDT WED APR 23 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...(THURSDAY THROUGH TUESDAY)
ISSUED AT 441 AM EDT WED APR 23 2014

MAIN FCST CONCERNS IN THE LONG TERM FOCUS ON THE POTENTIAL FOR HEAVY
PCPN ON THU INTO EARLY FRI AS WELL AS PTYPE.

AT 12Z THU...THE STRONGER NRN SHRTWV WL BE LOCATED NEAR THE CNDN
BORDER WITH MONTANA WHILE THE SRN DISTUBANCE SHIFTS E INTO THE
CENTRAL PLAINS... WITH ACCOMPANYING SFC LO PRES CENTERS NEARBY.
DESPITE THE SEPARATION BTWN THE INDIVIDUAL SHRTWVS...MODEL FCST RH
FIELDS SHOW WARM CONVEYOR BELT AREA OF HIER RH EXTENDING FM MN INTO
THE UPR LKS UNDER OVERAL SE FLOW TO THE E OF LARGER SCALE LO PRES
TROF IN THE PLAINS. H7 SPECIFIC HUMIDITY WITHIN THIS BAND AT THE
LATITUDE OF UPR MI IS FCST TO BE ABOUT 4 G/KG...BOOSTED BY H85 S
WINDS FCST UP TO 35-50 KTS E OF THE LARGER SCALE TROF AXIS. SO EVEN
THOUGH THE MODELS CONTINUE TO SHOW THE SRN SHRTWV WL REMAIN OUT OF
PHASE WITH THE NRN DISTURBANCE AND THAT ONLY THE STRONGER NRN SHRTWV
WL IMPACT THE CWA AS THESE DISTURBANCES MOVE TO THE E THRU FRI...
THERE WL BE ADEQUATE MSTR AVBL FOR POTENTIALLY HEAVY PCPN OVER UPR
MI AS THESE INDIVIDUAL DISTURBANCES MOVE INTO THE OHIO RIVER VALLEY
AND INTO THE UPR LKS RESPECTIVELY BY 12Z FRI. DIFFLUENT H3
FLOW/SHARP H4-2 DVGC E OF THE ARPCHG NRN SHRTWV WL ALSO ACT TO
ENHANCE PCPN RATES OVER THE CWA.

THE 00Z GFS/NAM INDICATE THE NRN SHRTWV WL TRACK THRU CENTRAL UPR
MI...WITH THE HEAVIEST PCPN MOST LIKELY TO THE N OF THE H85-7-5 LO
TRACK FM ABOUT IRONWOOD/ONTONAGON TO MARQUETTE BEFORE THE PCPN
SLOWLY DIMNISHES ON FRI WITH THE ARRIVAL OF DNVA/LARGER SCALE
QVECTOR DVGC IN THE WAKE OF THE DEPARTING SHRTWV INTO SE ONTARIO.
BUT THE 00Z UKMET AND THE 22/12Z AND 23/00Z ECMWF SHOW A FARTHER N
TRACK FOR THE NRN SHRTWV AND H85-7 LO ACRS THE NRN KEWEENAW...WITH
EARLIER DRY SLOTTING BY 06Z-12Z FRI AND A SHORTER WINDOW FOR HEAVIER
PCPN. THE 00Z CNDN MODEL IS A COMPROMISE BTWN THESE TWO CAMPS...BUT
SEEMS MORE ALIGNED WITH THE NCEP MODELS. 24 HR PCPN TOTALS THRU 12Z
FRI SHOWN BY THE NCEP MODELS RANGE FM 0.65-1.10 INCH...LEAST OVER
THE SE AND GREATEST OVER THE KEWEENAW ON THE CYC SIDE OF THE UPR LO
FCST TRACK. IN CONTRAST...THE 22/12Z ECWMF SHOWED 24 HR PCPN RANGING
FM 0.50 INCH OVER THE SE TO 0.75 INCH OVER THE KEWEENAW.

A MAJOR CONCERN THIS LATE IN THE SEASON IS ON PTYPE AND HOW SFC
TEMPS WL IMPACT SN ACCUM RATES. MODELS SHOW PCPN ARRIVING W-E ON
THU...REACHING NEWBERRY BY LATE IN THE AFTN. SINCE THE PCPN WL BE
ARRIVING DURING DAYTIME HEATING...WHEN H100-85 THKNS ARE FCST IN THE
1305-1310M RANGE...SUSPECT THE PCPN WL START AS RA OR A RA/SN MIX
OVER THE HIER TERRAIN WITH SOME EVAPORATIVE COOLING IN THE INITALLY
DRY LLVL AIR. EVEN WHERE SN IS MIXED IN WITH THE PCPN...EXPECT LTL
IF ANY SN ACCUMULATION ON WARMER SFCS LIKE ROADS. LOSS OF DAYTIME
HEATING/DYNAMIC COOLING WL ALLOW THE PCPN TO CHG TO PRIMARILY SN BY
00Z FRI AS H100-85 THKNS FALL TO 1295-1305M...ESPECIALLY AT
LOCATIONS TO THE N OF THE H85 LO TRACK. IN ADDITION TO THE WARM NEAR
SFC TEMPS...A HI AND THIN DGZ WL ALSO REDUCE SN/WATER RATIOS AND
MAKE THIS SN PARTICULARLY WET AND HEAVY. BEST BET ATTM IS FOR SN
TOTALS TO REACH 6 TO PERHAPS 8 INCHES OVER THE HIER TERRAIN OF THE
KEWEENAW GIVEN THE MORE FVRBL LOCATION RELATIVE TO THE H85-7 LO
TRACK. OTHER HIER TERRAIN LOCATIONS OVER THE NW HALF OF THE CWA MAY
SEE 2 TO 5 INCHES. THE FCST H85-7 LO TRACK ARGUES FOR MAINLY RA AND
LTL SN ACCUM OVER THE SE PORTION OF UPR MI.

SUSPECT FUTURE SHIFTS WL NEED TO ISSUE WINTER WX ADVYS FOR THE HIER
TERRAIN OF NW UPR MI. GIVEN THE GREAT UNCERTAINTY ON SHRTWV LO TRACKS
AND THE IMPACT OF TEMPS ON SN ACCUM RATES FOR A MAINLY 4TH PERIOD SN
FALL...OPTED TO UPDATE GOING SPECIAL WEATHER STATEMENT.

FRI NGT...ANOTHER SHRTWV DIVING ESEWD INTO THE UPR LKS BEHIND
DEPARTING SHRTWV MAY BRING SOME LGT SN/RA TO THE CWA. THE 00Z CNDN
MODEL IS STRONGEST WITH THIS DISTURBANCE AND GENERATES ANOTERH 0.50
INCH OF PCPN NEAR THE WI BORDER...BUT THIS STRONGER/WETTER SCENARIO
SEEMS UNREASONABLE GIVEN THE LARGER SCALE HGT RISES/DRYING THAT
WOULD BE EXPECTED OVER UPR MI IN THE WAKE OF THE DEPARTING INITIAL
STRONGER NRN SHRTWV.

EXTENDED...THE NW FLOW ALF E OF UPR RDG BLDG IN THE PLAINS IN THE
WAKE OF THE DEPARTING LO PRES AND TO THE S OF SPRAWLING HI PRES OVER
SCENTRAL CANADA ARE FCST TO PUSH DRIER AIR INTO THE UPR LKS STARTING
ON SAT. SOME OF THE LONGER RANGE MODELS SHOW NEXT SHRTWV LIFTING NE
OUT OF THE PLAINS BRINGING A RETURN OF PCPN AS EARLY AS SUN
NGTCONSIDERING THIS HUDSON BAY HI AND THE LIKELY DRY NNE FEED OF DRY
AIR THAT WL IMPACT THE AREA/CLIMATOLOGY OF HUDSON BAY HI PRES
SYSTEMS IN SPRING...OPTED TO CUT MODEL CONSENSUS POPS AND KEEP THE
FCST DRY THRU MON. TEMPS WL AVG BLO NORMAL DURING THIS TIME.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 439 AM EDT WED APR 23 2014

HIGH PRESSURE OVERHEAD THIS MORNING WILL SLOWLY EDGE TO OUR E DURING
THE LATE AFTERNOON HOURS...AND EXIT E OF UPPER MI OVERNIGHT. LOOK
FOR THIN HIGH CLOUDS TO THICKEN AND LOWER LATE THIS AFTERNOON
THROUGH DAYBREAK THURSDAY IN RESPONSE TO THE ELONGATED AREA OF LOW
PRESSURE NEARING FROM FROM S CANADA THROUGH THE S PLAINS. COULD HAVE
A CHANCE OF SNOW AND A SLIGHT CHANCE OF SNOW AT IWD JUST PRIOR TO
12Z THURSDAY...BEFORE CEILINGS BEGIN TO FALL BELOW VFR.

A LOW LEVEL JET NEARING 40KTS AROUND 2KFT WILL ARRIVE AROUND 12Z
THURSDAY AT IWD...WHICH MAY NECESSITATE THE INCLUSION OF LLWS AS SFC
WINDS REMAIN AROUND 10-15KTS. OTHERWISE...THE STRONGEST WINDS ABOVE
THE SFC LOOK TO HOLD OFF AT CMX AND SAW UNTIL MID AFTERNOON
THURSDAY.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM EDT WED APR 23 2014

HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT E TO CANADA
AND THE LOWER GREAT LAKES ON THURSDAY. THIS WILL MAKE WAY FOR THE
LOW STRETCHING FROM SOUTHERN SASKATCHEWAN TO IA AROUND DAYBREAK
THURSDAY TO PUSH ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT THROUGH
FRIDAY...BEFORE EXITING ACROSS LAKE HURON LATE FRIDAY AFTERNOON.
LOOK FOR A MIX OF RAIN AND SNOW OVER THE W HALF OF LAKE SUPERIOR BY
MID MORNING THURSDAY...BEFORE EXPANDING ACROSS THE REMAINDER OF THE
LAKE BY THE END OF THE DAY. PERIODS OF MODERATE SNOW MAY BE POSSIBLE
OVER MAINLY W LAKE SUPERIOR THURSDAY EVENING...AND ACROSS CENTRAL
AND E AREAS OVERNIGHT AS E WINDS GUSTS INTO THE 20-30KT RANGE. A FEW
GALES MAY STILL BE POSSIBLE...SO STAY TUNED TO LATER FCSTS.

LARGE HIGH PRESSURE OVER CENTRAL CANADA ON FRIDAY WILL PUSH ACROSS
HUDSON BAY SATURDAY...WHERE IT WILL REMAIN THROUGH SUNDAY. EXPECT A
RIDGE EXTENDING SOUTHWARD ACROSS LAKE SUPERIOR FRIDAY NIGHT TO
STRENGTHEN OVER THE AREA ON SATURDAY...AND LINGER INTO SUNDAY AS LOW
PRESSURE ORGANIZES ACROSS THE CENTRAL PLAINS. INCREASED
N-NW GUSTS NEARING 30KTS OR MORE MAY BE POSSIBLE AGAIN FRIDAY
AFTERNOON INTO EARLY SATURDAY...STRONGEST OVER CENTRAL AND E LAKE
SUPERIOR.
&&

.HYDROLOGY...
ISSUED AT 441 AM EDT WED APR 23 2014

THE ARRIVAL OF MUCH COLDER AIR IS LEADING TO GREATLY REDUCED
SNOWMELT RUNOFF OVER UPR MI. BUT SINCE RUNOFF FROM RECENT ABOVE
NORMAL TEMPS AND SNOWMELT CONTINUES TO FLOW THRU THE GROUND...SOME
AREA STREAMS AND RIVERS ARE STILL RISING SLOWLY. LOCATIONS
EXPERIENCING RISES NEAR OR ABOVE BANKFULL HAVE BEEN ALSTON AND
CHASSELL ON THE STURGEON RIVER...CRYSTAL FALLS ON THE PAINT
RIVER...AND HARVEY ON THE CHOCOLAY RIVER. SINCE CHILLY AND DRY
WEATHER WILL CONTINUE THRU TONIGHT...SNOWMELT AND RUNOFF SHOULD
DIMINISH AND PREVENT THESE RIVERS FROM EXCEEDING FLOOD STAGE IN THE
SHORT TERM.

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.

UNSETTLED WEATHER WILL RETURN THURSDAY AND THURSDAY NIGHT AS ANOTHER
LOW PRESSURE SYSTEM MOVES FROM THE PLAINS TOWARD THE GREAT LAKES...
POTENTIALLY ADDING TO RUNOFF LATER THIS WEEK. 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. 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...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...ROLFSON
LONG TERM...KC
AVIATION...KF
MARINE...KF
HYDROLOGY...KC




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