Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 302305
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
705 PM EDT SAT MAY 30 2015

.UPDATE...
ISSUED AT 704 PM EDT SAT MAY 30 2015
MUCH OF THE WEST HALF OF UPPER MICHIGAN HAS TOTALLY CLEARED OUT AS
THE HIGH BUILDS INTO THE UPPER GREAT LAKES. THE HRRR AND RAP SUGGEST
THAT THE WINDS ACROSS MUCH OF THE WEST HALF WILL DECOUPLE AND GO
LIGHT. WITH PRECIPITABLE WATER VALUES AT 0.25 INCH COMBINED WITH THE
LIGHT WINDS AND CLEAR SKIES...SEE NO REASON WHY MANY LOCATIONS IN
THE FREEZE WARNING WILL NOT DROP INTO THE 20S...ESPECIALLY WITH SFC
DWPTS IN THE UPPER 20S ATTM. IN FACT...HAVE OPTED TO ALSO PLACE
MARQUETTE...BARAGA AND DICKINSON COUNTIES IN THE FREEZE WARNING
MAINLY DUE TO THE LIKELIHOOD THAT THE NORMALLY COLDER LOCATIONS WELL
INLAND FROM THE LAKE /CHAMPION...MICHIGAMME...THREE LAKES...HERMAN/
WILL ALSO SEE A PERIOD OF TIME WITH TEMPS BELOW 30. THOSE WHO HAVE
OUTDOOR PLANTS ARE ADVISED TO PROTECT THEM FROM THE COLD IF
POSSIBLE.
&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 325 PM EDT SAT MAY 30 2015

WIDESPREAD FROST EXPECTED TONIGHT OVER MUCH OF W AND CENTRAL UPPER
MI...AS COOL/DRY HIGH PRESSURE FROM S MANITOBA AND FAR W ONTARIO
BUILDS A STRONGER RIDGE INTO W UPPER MI. A TIGHTER PRESSURE GRADIENT
OVER THE E HALF MOST OF THE NIGHT WILL KEEP WINDS CLOSER TO 4-8KTS.
OVER THE W...NEAR CALM WINDS AND THE PW VALUES HOVERING AROUND
0.25IN WILL ALLOW SFC TEMPS TO FALL BELOW 32F. A FEW OF THE
TYPICALLY COOLER FIRE WX RAWS MAY ALSO FALL BELOW 32F OVER THE
E...BUT IT WILL LIKELY NOT BE WIDESPREAD.

FOR SUNDAY...NE WINDS WILL BE COMMON AS THE AREA OF HIGH PRESSURE
LINGERS ACROSS LAKE SUPERIOR. A LAKE MI LAKE BREEZE WILL ATTEMPT TO
MOVE IN RIGHT ALONG THE SHORELINE. THIS SHOULD KEEP ISQ TO ESC AND
MNM IN THE 50S. ALONG N CENTRAL AND E LAKE SUPERIOR UPPER 40S AND
LOW 50S ARE MORE LIKELY...WITH 60S POSSIBLE WELL INLAND ALONG THE WI
BORDER. WILL LIKELY HAVE CLOUDS /ABOVE 600MB/ ROLL IN FROM THE NW
DURING THE AFTERNOON HOURS...ASSOCIATED WITH THE NEARING SHORTWAVE
ACROSS SW ONTARIO.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 317 PM EDT SAT MAY 30 2015

FAIR AGREEMENT IN GENERAL LOOK OF UPPER LEVEL PATTERN THROUGH NEXT
WEEKEND. DEEP TROUGH THAT IS OVER EASTERN CANADA THIS WEEKEND MOVES
EAST BY SUNDAY EVENING. SECONDARY WEAKER SHORTWAVE CURRENTLY OVER
NORTHERN MANITOBA AND SASKATCHEWAN SHOULD DROP ACROSS NW ONTARIO ON
MONDAY WHILE DEEPENING A TOUCH. ONLY IMPACT FM THIS TROUGH WOULD BE
SCT-BKN HIGH CLOUDS OVER UPR MICHIGAN ON SUNDAY NIGHT WHICH MAY
AFFECT FROST/FREEZE POTENTIAL. DID NOT RAISE TEMPS TOO MUCH FM
PREVIOUS FORECAST THOUGH SINCE PWATS ARE STILL LOW AROUND 0.30 INCH
AND WITH EVEN A FEW HOURS OF CLEAR SKIES TEMPS WOULD FALL OFF INTO
THE UPR 20S OR LOWER 30S AS HIGH PRESSURE IS OVERHEAD.

TROUGH ALOFT WEAKENS AND HEADS EAST MONDAY AND MONDAY NIGHT. TEMPS
WILL STILL BE BLO NORMAL ON MONDAY. COOLEST READINGS IN THE 40S AND
50S NEAR LK SUPERIOR WITH ONSHORE WINDS ALL DAY. WARMEST READINGS
INLAND WEST WHERE TEMPS REACH MID TO POSSIBLY UPR 60S. SFC HIGH
PRESSURE RIDGE REMAINS CLOSE ENOUGH TO SUPPORT ANOTHER CHILLY/FROSTY
NIGHT OVER THE INTERIOR CNTRL AND EAST ON MONDAY NIGHT.

HEIGHTS ALOFT RISE TUESDAY INTO WEDNESDAY BTWN DEPARTING TROUGH OVER
EASTERN CANADA AND STRONGER TROUGH THAT MOVES OVER THE WESTERN CONUS
EARLY THIS WEEK. AT THE SFC...HIGH PRESSURE RIDGE SHIFTS OVER THE
LOWER GREAT LAKES ON WEDNESDAY WHILE A LOW PRESSURE TROUGH SLOWLY
FORMS OVER THE HIGH PLAINS. PRIMARY MODELS SHOWING DISAGREEMENT HOW
QUICK A WEAKER SHORTWAVE RIDES ALONG IN WSW FLOW ALOFT AND BRINGS
RAIN BACK OVER UPR MICHIGAN ON WEDNESDAY.

GFS BRINGS THE SHORTWAVE AND H85-H7 AND H7-H5 Q-VECTOR CONVEGENCE
AND MID LEVEL MOISTURE OVER MAINLY WESTERN LK SUPERIOR AND NW CWA ON
WEDNESDAY AFTN. ECMWF IS FARTHER EAST WITH THE MOISTURE. LINGERING
WEAK SFC GRADIENT COULD SUPPORT LAKE BREEZES ON WEDNESDAY AFTN...BUT
DOES NOT LOOK LIKE MUCH INSTABILITY WILL BE OVER UPR MICHIGAN AT
THAT POINT. OVERALL SOME ISOLD SHRA MAY MAKE IT INTO WEST UPR
MICHIGAN WED AFTN AS THERE IS SOME MID-LEVEL MOISTURE ADVECTION WELL
AHEAD OF THE WAVE /MORE SO ON THE GEM-NH/...BUT NOT EXPECTING ANY
TSRA. THOUGH INITIAL SHORTWAVE LIFTS NORTH OF LK SUPERIOR ON WED
NIGHT THERE ARE HINTS ADDITIONAL WAVES MAY BE LIFTING IN DUE TO
UPSTREAM SHRA/TSRA OR JUST BECAUSE REGION IS ON THE LEADING EDGE OF
LARGER WEST CONUS TROUGH. HARD TO TIME...SUBTLE SHORTWAVES TYPICALLY
WILL SHOW UP IN THE WSW FLOW AHEAD OF LARGER SCALE TROUGH TO THE
WEST. INCREASING H85 MOISTURE TRANSPORT AHEAD OF LOW PRESSURE TROUGH
IN THE NORTHERN PLAINS COULD TRIGGER SHRA/TSRA AS IT INTERACTS WITH
ELEVATED INSTABILITY /1000-700MB MUCAPES 500-1000J/KG SLIDING IN FM
NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY/. H85-H7 FLOW IS
FM WSW SO THIS COULD PROPEL SHRA/TSRA THAT DEVELOP UPSTREAM CLOSER
TO HIGHER INSTABILITY OVER WESTERN CWA. PWATS UP TOWARD 1.5 INCHES
AND WEAKER CORFIDI VECTORS COULD RESULT IN HEAVY RAIN POTENTIAL IF
SHRA/TSRA OCCUR. GEM-NH IS MOST AGGRESSIVE WITH FARTHER EAST SOLN
INTO WEDNESDAY NIGHT...BUT NOW THE ECMWF AND GFS ARE SLOWER. POPS
WILL BE KEPT IN THE CHANCE RANGE...PRETTY SIMILAR TO CONSENSUS. DID
LOWER POPS INITIALLY TUE NIGHT INTO WED BASED ON SLOWER TRENDS.

LOW PRESSURE TROUGH AND A SFC LOW REMAIN OVER THE NORTHERN PLAINS ON
THURSDAY. MEANWHILE...ANOTHER WEST-EAST FRONT SLOWLY DROPS ACROSS
THE NORTHERN PLAINS AND LK SUPERIOR AHEAD OF COOLER CANADIAN HIGH
PRESSURE OVER MANITOBA AND ONTARIO. CONVERGENCE OF THE MOISTURE
ADVECTION ALONG THE BOUNDARIES PROBABLY KEEP THE RAIN CHANCES GOING
ON THURSDAY. STRONGER MOISTURE TRANSPORT AND INSTABILITY IS OVER MID
TO UPPER MISSISSIPPI RIVER VALLEY...BUT SIMILAR TO WEDNESDAY
NIGHT...H85/H7 WINDS FM SW COULD PULL MORE FAVORABLE THERMODYNAMICS
AND MOISTURE BACK OVER UPR MICHIGAN. LIKELY THE POPS THROUGH THE
LATE WEEK PERIOD WILL BE HIGHEST ON THURSDAY NIGHT INTO FRIDAY AS
THE CANADIAN FRONT SLIDES OVERHEAD AND THE PLAINS LOW MOVES OVER THE
UPPER GREAT LAKES REGION ALL WHILE DEEPER FORCING FM MAIN SHORTWAVE
CROSSES THE REGION. SEEMS THAT GREATEST INSTABILITY SHOULD BE AT ITS
MAX POINT THURSDAY NIGHT INTO FRIDAY...BUT MODELS DIFFER ON HOW THAT
WILL SHAKE OUT. GFS NOT AS AGRESSIVE IN BRINGING CONVECTION AS FAR
NORTH AS UPR MICHIGAN EITHER THURSDAY NIGHT OR FRIDAY. ECMWF WAS
MUCH MORE BULLISH...LIKELY DUE TO STRONGER SHORTWAVE IT RIDES OVER
THE EAST TO WEST FRONT THURSDAY NIGHT INTO FRIDAY. ECMWF ONLY HAD
THIS STRONGER SHORTWAVE SINCE 12Z RUN ON 29 MAY...AND LATEST RUN
NOW IS QUITE WRAPPED UP WITH WAVE...AND HAS MORE OF A WRAPPED UP SFC
LOW TRACKING WEST OF LK SUPERIOR AND UPR MICHIGAN AS LATE AS FRIDAY
EVENING. WILL HAVE TO SEE IF THIS NEW TREND CONTINUES OR THE ECMWF
GOES BACK TO A WEAKER LOW. TEMPS FOR LATE WEEK WILL TREND ABOVE
NORMAL. DAYTIME HIGHS COULD BE HELD DOWN DUE TO CLOUDS AND RAIN
CHANCES. NO MATTER...EXPECT HIGHS WELL INTO THE 70S THURSDAY AND
FRIDAY. HUMIDITY WILL INCREASE THURSDAY AND FRIDAY AS H85 DWPNTS
SURGE ABOVE +12C ALONG AND SOUTH OF THE WEST-EAST FRONTAL BOUNDARY.

SIMILAR TO TODAY...COLD FRONT WILL PUSH SOUTH OF UPR MICHIGAN NEXT
SATURDAY. AT LEAST AT FIRST GLANCE...AIRMASS NEXT WEEKEND DOES NOT
APPEAR AS COLD AS THE ONE AFFECTING ONTARIO/QUEBEC AND THE UPPER
GREAT LAKES THIS WEEKEND. THOUGH RAIN CHANCES WILL DIMINISH BY NEXT
SATURDAY...SHOULD SEE SCT-BKN LOW CLOUDS IN WAKE OF THE FRONT. GFS
AND ECMWF HINT AT IT. LOWERED TEMPS OVER CONSENSUS CLOSER TO LK
SUPERIOR WITH STIFF NE WINDS FLOWING OVER THE CHILLY LK SUPERIOR
WATER TEMPS /UPR 30S TO LOWER 40S AS OF THIS MORNING PER MTU AND
NOAA BUOY DATA/.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 216 PM EDT SAT MAY 30 2015

MVFR CEILINGS AT IWD AND SAW ARE QUICKLY MOVING BACK TO VFR AT THE
THICK CLOUDS SINK SE OF THE SITES. AFTER...LOOK FOR VFR CEILINGS/VIS
TO REMAIN THROUGH THE REST OF THE FCST PERIOD. THE N WINDS GUSTING
18-25KTS AT CMX AND SAW WILL BE QUICKLY DIMINISHING THIS EVENING AS
A RIDGE OF HIGH PRESSURE OVER FAR W ONTARIO PUSHES OVER THE REGION.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 325 PM EDT SAT MAY 30 2015

HIGH PRESSURE WILL DOMINATE MUCH OF THIS PERIOD WITH WIND GUSTS LESS
THAN 25KTS. EXPECT HIGH PRESSURE INITIALLY OVER W LAKE SUPERIOR TO
EXPAND ACROSS ALL OF LAKE SUPERIOR...AND THEN WEAKEN SLIGHTLY BY
TUESDAY AS IT SHIFTS TO THE LOWER GREAT LAKES. LOW PRESSURE OVER THE
DAKOTAS TUESDAY NIGHT WILL CROSS MN WEDNESDAY INTO WEDNESDAY
NIGHT...BEFORE WEAKENING TO A TROUGH THAT WILL EXPAND ACROSS ALL OF
LAKE SUPERIOR WEDNESDAY NIGHT THROUGH THURSDAY...AS DEEPER LOW
PRESSURE ORGANIZES ACROSS THE CENTRAL PLAINS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  FROST ADVISORY FROM MIDNIGHT EDT /11 PM CDT/ TONIGHT TO 8 AM EDT
     /7 AM CDT/ SUNDAY FOR MIZ001-003-006-012-013.

  FREEZE WARNING FROM MIDNIGHT EDT /11 PM CDT/ TONIGHT TO 8 AM EDT
     /7 AM CDT/ SUNDAY FOR MIZ002-004-005-009>011-084.

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

$$

UPDATE...MRD
SHORT TERM...KF
LONG TERM...JLA
AVIATION...KF
MARINE...KF


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