Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 191530 AAA
AFDMQT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MARQUETTE MI
1130 AM EDT SAT APR 19 2014

.UPDATE...
ISSUED AT 1129 AM EDT SAT APR 19 2014

UPDATED THE GOING POP/WX/QPF GRIDS THROUGH TONIGHT...LARGELY TO
DEAL WITH THE TRENDS SHOWN IN THE HIGHER RESOLUTION RUNS
(HRRR/RAP/HOPWRF) AND THE INITIAL VIEWS OF THE 12Z
NAM/GEM-REGIONAL. ALL OF THESE MODELS SHOW THE INITIAL WAVE OF
PRECIPITATION CURRENTLY OVER WESTERN LAKE SUPERIOR TO SHIFT TO THE
NORTHEAST OVER THE NEXT COUPLE OF HOURS AS THE MAIN PUSH OF
850-700MB WAA MOVES OVER NORTHERN LAKE SUPERIOR. AS THIS
OCCURS...COULD SEE A BRIEF PERIOD OF PRECIPITATION OVER THE WESTERN
SHORELINE OF ONTONAGON/HOUGHTON COUNTIES AND ALSO KEWEENAW COUNTY.
WITH SURFACE TEMPERATURES WARMING ABOVE FREEZING...DON/T EXPECT ANY
CONCERN FOR FREEZING RAIN. BUT THERE COULD BE A SNOW OR RAIN/SNOW
MIX BEFORE CHANGING TO ALL RAIN...AS WETBULB ZEROS ARE BETWEEN
700-1100FT INITIALLY. OTHERWISE...THINK THE PRIMARY PRECIPITATION
(RAIN) WILL ARRIVE LATER THIS AFTERNOON OVER THE WEST...ASSOCIATED
WITH THE MID LEVEL TROUGH AND PRECIP MOVING THROUGH CENTRAL
MINNESOTA. THUS...HAVE SHOWN A DRIER TREND TO THE CENTRAL CWA FOR
THIS AFTERNOON AND HAVE THAT PRECIP ARRIVING DURING THE MID EVENING
HOURS. THE POPS FOR THE REST OF THE NIGHT SEEMED REASONABLE WITH ONLY
MINOR TWEAKS MADE. DID TREND THE QPF VALUES DOWN SOME FOR TONIGHT
BASED OFF THE LATEST HIGH RESOLUTION GUIDANCE TRENDING TOWARDS LOWER
QPF OVER THE WEST CENTRAL...AS THE LOW/MID LEVEL FORCING BECOME
DISPLACED UNTIL THE LATE OVERNIGHT HOURS AND INCREASES THE PRECIP
OVER THE EAST.
&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT SAT APR 19 2014

WV LOOP SHOWS A VIGOROUS SHORTWAVE CROSSING SOUTHERN SASKATCHEWAN
THIS MORNING. SFC LOW IS TIED TO THE WAVE IN SIMILAR LOCATION WITH
TROUGH EXTENDING INTO THE DAKOTAS. MEANWHILE...CONFLUENT FLOW ALOFT
IS SUSTAINING LARGE HIGH PRESSURE RIDGE FROM JAMES BAY ACROSS THE
UPPER GREAT LAKES. GRADIENT OF MOISTURE IS EVIDENT WITH 00Z RAOBS
SHOWING PWATS VARYING FM AROUND 0.20 INCHES AT KINL TO NEAR 0.70
INCHES AT KBIS. WARM AIR ADVECTION NOTICABLE WITH +10C H85 TEMP AT
KBIS AND -4C AT KINL AND KGRB. ALREADY SEEING CLUSTER OF SHOWERS
DEVELOPING IN THIS WARM AIR ADVECTION REGIME WITHIN LAST FEW HOURS
OVER MAINLY NORTHERN HALF OF MN. SOME LIGHTER RADAR ECHOES ARE
PUSHING ACROSS WESTERN UPR MICHIGAN...BUT DUE TO THE DRY AIR BLO H8
IN VCNTY OF SFC RIDGE...IT IS NOT LIKELY REACHING THE GROUND AS ANY
PRECIP. PRECIP OVER MN IS MAINLY ALONG AND AHEAD OF BEST H7 MOISTURE
TRANSPORT AND WITHIN SWATH OF H925-H7 WARM AIR ADVECTION. EXPECT
PRECIP TO EVENTUALLY WORK ITS WAY TO SFC OVER WESTERN UPR MICHIGAN
THIS MORNING GIVEN STRENGTH OF THE MID LEVEL MOISTURE/TEMPERATURE
ADVECTION.

AS IT HAS LOOKED FOR A WHILE...PTYPE COULD BE BRIEF ISSUE AS THE
PRECIP FIRST BEGINS. SOUNDINGS INDICATE SNOW AND FREEZING RAIN COULD
BOTH BE POSSIBLE MAINLY OVER KEWEENAW THIS MORNING. SNOW AMOUNTS
WILL BE MINIMAL AND ANY ICE AMOUNTS SHOULD BE LESS THAN 0.05 INCH.
BY LATE MORNING...LOW-LEVEL SFC WARM AIR ADVECTION WILL ALLOW
PRECIP TO TAKE FORM OF RAIN. QUANDARY FOR TODAY IS JUST HOW MUCH
PRECIP WILL OCCUR OVER NORTHWEST CWA. NO DOUBT THE TEMP ADVECTION IS
STRONG AND ISENTROPIC ASCENT IS FOCUSED...BUT PREFER TO LEAN AWAY FM
THE RATHER WET GFS OUTPUT...TRACKING A BULLSEYE OF WELL OVER 0.5
INCH OF QPF FM WESTERN LK SUPERIOR TO THE KEWEEANW PENINSULA. SREF
PROBS OVER NORTHWEST CWA SHOW LESS THAN 10 PCT PROBABILITY OF SEEING
SUCH AMOUNTS. GIVEN THE DRY LOW-LEVELS WHICH ARE NOT COMPLETELY
ERODED...PREFER THE DRIER LOOK OF THE NAM/REGIONAL GEM AND ECMWF.
BATCH OF SHOWERS WILL GRADUALLY SINK ESE INTO CNTRL CWA BY LATE THIS
AFTN. DESPITE THE CLOUDS/RAIN IN SOME AREAS...MIXING TO 925-900MB
STILL INDICATES TEMPS LATER TODAY COULD REACH UPR 40S OR EVEN LOWER
50S. COOLEST TEMPS WHERE SE LOW-LEVEL WINDS AHEAD OF THE LOW REMAIN
ONSHORE...SO GENERALLY KEWEENAW AND NEAR THE LK MICHIGAN SHORE.

EXPECT RAIN TO BECOME QUITE WIDESPREAD TONIGHT OVER ESPECIALLY THE
CNTRL AND EAST CWA. PRIMARY SHORTWAVE AS IMPRESSIVE AS IT LOOKS
NOW...DEFLECTS MORE NORTH ACROSS MANITOBA AND NORTHERN ONTARIO
INSTEAD OF TRACKING EAST ACROSS UPR GREAT LAKES. SFC LOW WILL FOLLOW
SUIT...LEAVING WEAKENING SFC TROUGH TO PUSH OVER THE UPPER GREAT
LAKES TONIGHT...SLOWING DOWN AS IT DOES SO SINCE UPPER FLOW BECOMES
PARALLEL TO THE SFC FRONT. APPEARS WARM AND MOIST ADVECTION ALONG
WITH DIVERGENCE ALOFT OF INCREASING JET STREAK ACROSS LK SUPERIOR
AND NORTHERN ONTARIO WILL BE PRIMARY DRIVING FORCES BEHIND PRECIP
CHANCES THROUGH LATE TONIGHT. H85 TROUGH IS FORECAST TO SHIFT WEST
TO EAST ACROSS UPR MICHIGAN TONIGHT OUTPACING THE SFC FRONT...AND
THIS ALONG WITH INCREASING H85-H7 MOISTURE TRANSPORT INTO THE
TROUGH WITH PWATS SURGING UP NEAR 200 PCT OF NORMAL WILL FOCUS
WIDESPREAD RAIN ACROSS MUCH OF THE CWA. NAM/GEM-REGIONAL
AND ECMWF WHICH WERE PREFERRED DURING THE DAYTIME TODAY...APPEAR TOO
LIGHT WITH QPF. ON FLIP SIDE...00Z GFS STILL APPEARS TOO WET SHOWING
6 HR QPF AMOUNTS OVER 0.90 INCHES...BUT THINK AN AREA OF RAIN WITH
AMOUNTS 0.25-0.50 INCH IN 6 HOURS IS LIKELY GIVEN THE EXTENT OF MOISTURE
AIMED RIGHT INTO CNTRL UPR MICHIGAN ON NOSE OF 45-50 KT SW H85 JET.
RAMPED UP POPS TO CATEGORICAL LATER THIS EVENING THROUGH THE
OVERNIGHT HOURS. BY LATE TONIGHT...AFT 06Z CNTRL AND 09Z EAST...H85
TROUGH SLIDES MAINLY TO THE SOUTH AND EAST OF CWA...ENDING POTENTIAL
FOR HIGHER POPS.

ONCE THE RAIN DIMINISHES OVER THE WEST TONIGHT...EXPECT SFC DWPNTS
TO PUSH UP AROUND 40 DEGREES WHICH FLOWING OVER A WET AND MELTING
SNOWPACK SHOULD RESULT IN GOOD DEAL OF FOG ESPECIALLY AS SOUNDINGS
SHOW MID-LEVEL DRYING OCCURRING ATOP SATURATED SUB H85 LAYER. FOG
COULD FORM LATER IN THE EAST AS WELL AS THE RAIN ENDS...BUT FOR NOW
JUST KEPT IT IN FOR AREAS WHERE DWPNTS GET AT LEAST INTO THE MID 30S
AND THE LARGER SCALE SETUP IS FAVORABLE FOR FOG. A MILD NIGHT WITH
THE HIGHER DWPNTS AS MOST AREAS STAY IN THE UPR 30S OR LOWER 40S.
INTERIOR WEST CWA MAY SEE TEMPS AS LOW AS MID 30S WHICH WOULD
PROBABLY RESULT IN DENSE FOG.

LAST BUT CERTAINLY NOT LEAST...GIVEN THE WARMER TEMPS...RAIN...AND
MELTING SNOW...EXPECT RIVER LEVELS TO BEGIN RISING TONIGHT AND WE
COULD BEGIN TO SEE ICE JAM ISSUES DEVELOP AGAIN. MORE DETAILS ON
THIS ARE IN THE HYDROLOGY SECTION BELOW.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 428 AM EDT SAT APR 19 2014

MAIN FCST CONCERN IN THE LONGER TERM IS FOCUSED ON THE POTENTIAL
INTERACTION BTWN A STALLED FNT/RIBBON OF HIER MSTR JUST S OF UPR MI
AND A SHRTWV THAT IS FCST TO MOVE E ACRS SRN CANADA ON MON AND IF/
HOW MUCH RA WL FALL OVER UPR MI AND IMPACT AREA STREAMS/HYDRO.
CONFIDENCE IN THIS FCST IS LOWERED BY POOR MODEL AGREEMENT ON THE
INTERACTION BTWN THESE FEATURES.

SUN...AS SHRTWV/SFC LO OVER NW ONTARIO ON SUN MRNG MOVE E CLOSER TO
JAMES BAY BY LATE IN THE DAY...A SHRTWV RDG AND MID LVL DRYING ARE
FCST TO ADVANCE INTO THE UPR LKS BEHIND DEPARTING/WEAKENING
ATTENDANT COOL FNT AND WARM CONVEYOR BELT MSTR RIBBON. ALTHOUGH SOME
MODEL DIFFERENCES REMAIN ON HOW AGGRESSIVE THIS MID LVL DRYING WL
BE...THE PREVIOUSLY SLOWER CNDN MODEL SHOWS ENUF DRYING TO END THE
PCPN OVER ALL BUT THE FAR SE CWA BY 00Z. OPTED TO RETAIN FLAVOR OF
GOING FCST THAT SHOWS LINGERING POPS OVER THE SE HALF DIMINISHING
THRU THE DAY...AND ENDING OVER ALL BUT THE FAR SE BY 00Z MON.
OTRW...WITH DIURNAL HEATING...EXPECT LO CLDS/FOG OVER THE MELTING SN
PACK TO DSPT BY THE AFTN. H85 TEMPS IN THE 6-8C RANGE WL SUPPORT ABV
NORMAL TEMPS...BUT LGT WINDS ASSOCIATED WITH WEAK HI PRES UNDER THE
SHRTWV RDGING SHOULD ALLOW FOR LK BREEZES THAT WL BRING LOCAL
COOLING NEAR THE SHORES.

SUN NGT/MON...SUN NGT WL START DRY EXCEPT PERHAPS OVER THE FAR
SCENTRAL CLOSER TO LINGERING STNRY FNT/MSTR AXIS. BUT AS NEXT SHRTWV
MOVING ESEWD ACRS SCENTRAL CAN IN THE NW FLOW E OF BLDG RDG OVER WRN
CANADA APRCHS AND GENERATES SOME HGT FALLS OVER THE UPR LKS...SOME
OF THE MODELS...ESPECIALLY THE 00Z ECWMF/UKMET...SHOW DEEP MSTR TO
THE S EXPANDING BACK TO THE N LATE SUN NGT AND IMPACTING MAINLY THE
SCENTRAL AND E. THE NCEP MODELS ARE MUCH DRIER AND INDICATE MAINLY
SCT RA SHOWERS ASSOCIATED WITH THE PASSAGE OF THE INCOMING SHRTWV.
THE 00Z CNDN MODEL SHOWS THE PCPN EXPANDING BACK FARTHER TO THE N
BUT NOT UNTIL MON. WHILE THE BLDG RDG OVER THE SE CONUS SUPPORTS THE
FARTHER N SCENARIO FAVORED BY THE NON NCEP MODELS...THE RATHER LARGE
SEPARATION BTWN THE DISTURBANCES IN QUESTION AND ABSENCE OF A SGNFT
BACKING OF THE UPR LVL WINDS TO A MORE SW DIRECTION INDICATE THE
DRIER NCEP GUIDANCE IS ON THE RIGHT TRACK. THE MODELS TYPICALLY HAVE
A DIFFICULT TIME HANDLING INTERACTION/PHASING BTWN DISPARATE
DISTURBANCES...SO CONFIDENCE IS LO IN THIS PORTION OF THE FCST.
FORTUNATELY...EVEN THE WETTER SCENARIO FAVORED BY THE NON NCEP
MODELS POINTS TO HEAVIER RA OVER THE SCENTRAL AND ERN CWA...WHERE
LESS SN REMAINS. OTRW...MAINTAINED MENTION OF PATCHY FOG LATE SUN
NGT INTO MON MRNG WITH LGT WINDS/POTENTIAL FOR DRIER MID LVLS OVER
MELTING SN.

MON NGT...INCRSG NNW FLOW WITH H925 WINDS INCRSG UP TO 25-30 KTS
ASSOCIATED WITH DIGGING SHRTWV THRU THE GREAT LKS IS FCST TO DROP
H85 TEMPS AS LO AS -6 TO -7C BY 12Z TUE. WHILE THE INCOMING AIRMASS
IS NOT COLD ENUF FOR LK EFFECT SN...SOME OF THE MODELS SHOW ENUF
LLVL MSTR TO JUSTIFY CHC POPS. WITH THE ARRIVAL OF THE COLDER AIR...
EXPECT THE RA SHOWERS TO MIX WITH OR CHG TO SN...ESPECIALLY OVER THE
HIER TERRAIN OF THE W.

TUE INTO WED...CNDN SFC HI PRES RDG UNDER UPR RDG TRAILING DEPARTING
SHRTWV WL BRING A PERIOD OF COOLER AND DRIER WX TO THE CWA.

EXTENDED...NOT SURPRISINGLY...THERE REMAINS SGNFT DISAGREEMENT AMONG
THE LONGER RANGE MODELS ON THE HANDLING OF NEXT LO PRES THAT IS
LIKELY TO IMPACT THE UPR LKS LATER ON WED INTO FRI. THE 00Z ECMWF
INDICATES A COLDER SCENARIO WITH THE SFC LO PRES TRACKING TO THE S
OF UPR MI AND BLDG HI PRES JUST N OF LK WINNIPEG. THIS FCST WOULD
RESULT IN SOME MIXED PCPN AT THE ONSET AND LATER IN THE WEEK. THE
00Z GFS AND CNDN MODELS ON THE OTHER HAND SHOW A DEEPER LO FARTHER
TO THE N ALONG WITH A STRONGER SLY FLOW OF WARMER AIR. WL RELY ON
MODEL CONSENSUS FOR NOW.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 741 AM EDT SAT APR 19 2014

ALTHOUGH MOISTURE ALOFT CONTINUES TO INCREASE TODAY...LINGERING DRY
LOW-LEVELS SHOULD ALLOW CONDITIONS TO REMAIN VFR EVEN IF SOME RAIN
OCCURS. BEST CHC OF MORE STEADIER SHOWERS IS THIS AFTN AT KCMX SO
HAVE WENT WITH AN MVFR VSBY. SPRINKLES MAY AFFECT KIWD MAINLY IN
THE MORNING. KSAW SHOULD STAY DRY TODAY. BETTER CHC OF SHRA WILL
OCCUR LATE AFTN INTO THE EARLY EVENING AT KIWD/KCMX AND LATER IN
THE EVENING THROUGH THE EARLY OVERNIGHT HOURS AT KSAW. DEPENDING
ON HOW MUCH RAIN OCCURS TODAY AND HOW QUICKLY MID-LEVEL MOISTURE CAN
DEPART LATER TONIGHT...SOME FOG IS POSSIBLE LATE TONIGHT AT ALL THE
TERMINALS. WITH UNCERTAINTY...DID NOT INCLUDE ANYTHING LOWER THAN
MVFR VSBY ATTM.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 509 AM EDT SAT APR 19 2014

EAST TO SOUTHEAST WINDS LIKELY 25-30 KTS TODAY INTO TONIGHT AS LOW
PRESSURE LIFTS FROM MANITOBA ACROSS NORTHERN ONTARIO. EXPECT WINDS
TO STAY BELOW 25 KTS THROUGH THE REST OF THE FORECAST PERIOD.
&&

.HYDROLOGY...
ISSUED AT 507 AM EDT SAT APR 19 2014

AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS...THE RECENT HEAVY
SNOWFALL ACROSS WESTERN UPPER MI HAS REPLENISHED SOME OF THE WATER
CONTENT THAT WAS LOST DURING THE WARMER CONDITIONS OVER THE PAST TWO
WEEKS. THE WESTERN HIGH TERRAIN NOW HAS 6 TO 8 INCHES OF WATER
EQUIVALENT...WITH LOCALIZED 10 INCH AMOUNTS. SINCE TEMPERATURES ARE
EXPECTED TO BE AT OR SLIGHTLY ABOVE AVERAGE ACROSS UPPER MI THIS
WEEKEND INTO MON /THE UPPER 50S AND LOW 60S AWAY FROM LOCAL LAKE
COOLING ON SUN AND MON/ WITH DEWPTS RISING AS HI AS THE LO 40S...A
GOOD DEAL OF MELTING SHOULD OCCUR. EXCEPT FOR TONIGHT...LO TEMPS WILL
FALL TO AT LEAST NEAR FREEZING...LIMITING CONCERNS OF RAPID MELTING.
COOLER AIR WILL RETURN MON NIGHT INTO THU...SOMEWHAT MODERATING THE
MELT DOWN. HIGHS ARE STILL EXPECTED TO RANGE FROM THE 40S TO THE LOW
50S.

AS FOR PRECIPITATION...AN ADDITIONAL 0.25 TO 0.75 INCH OF LIQUID IN
THE FORM OF MOSTLY RAIN IS EXPECTED THIS AFTERNOON INTO EARLY SUN
AFTERNOON. FORTUNATELY...THE HEAVIER RAIN IS FORECAST OVER THE EAST
WHERE THERE IS GENERALLY LESS SNOW ON THE GROUND. BUT WITH THE
ADDITIONAL LIQUID ADDED TO THE SNOWPACK FROM THE RECENT SNOW
STORM...WARM TEMPERATURES/GREATER SN MELT...AND LIGHT TO MODERATE
RAINFALL...A PROLONGED PERIOD OF HIGHER RIVER FLOWS ARE EXPECTED.

THOUGH WIDESPREAD FLOODING IS NOT A CONCERN AT THIS TIME...REMAINING
ICE ON THE RIVERS COULD LEAD TO POTENTIAL ICE JAMS ONCE THE WARMER
AIR ARRIVES THRU MON. THOSE LIVING AROUND RIVERS...CREEKS...AND
STREAMS SHOULD MONITOR BOTH RIVER LEVELS AND ICE CONDITIONS. ICE
JAMS CAN FORM AND BREAK QUICKLY...RESULTING IN RAPIDLY FLUCTUATING
RIVER LEVELS.
&&

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

$$

UPDATE...SRF
SHORT TERM...JLA
LONG TERM...KC
AVIATION...JLA
MARINE...JLA
HYDROLOGY...KC







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