Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 241959
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
359 PM EDT SUN MAY 24 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 251 AM EDT SUN MAY 24 2015

UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER THE CENTRAL
ROCKIES WITH A SHORTWAVE RIDGE OVER THE SOUTHEAST AND GREAT LAKES
REGION. THE RIDGE MOVES SLOWLY EAST TODAY WHILE A TROUGH MOVES INTO
THE PLAINS AND THIS TROUGH AFFECTS THE UPPER GREAT LAKES TONIGHT.

NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE AND SOME DEEPER
MOISTURE INTO THE CWA TONIGHT. GFS AND ECMWF DO ABOUT THE SAME THING
AS WELL. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST EXCEPT TO DELAY POPS FOR LATE THIS AFTERNOON. SOME OF THE
MODELS ARE SHOWING SOME CONVECTION THIS AFTERNOON WITH LAKE
BREEZES...BUT THINKING IS THIS IS OVERDONE WITH A VERY DRY AIRMASS
IN PLACE...WOULD BE HARD TO GET ANY CONVECTION GOING.
ECMWF...CANADIAN...NAM ALL HAVE BACKED OFF ON ANY PCPN FOR THIS
AFTERNOON AND WILL GO WITH THAT IDEA. DID BRING IN SOME CATEGORICAL
POPS FOR TONIGHT AS A BAND OF HEAVY RAIN MOVES THROUGH THE AREA.
WITH THIS RAIN...FOG BECOMES A POSSIBILITY ESPECIALLY IN THE LAKES
AND KEPT THAT IN THERE AS WELL. WILL BECOME A VERY GOOD POSSIBILITY
WHEN RAIN FALLS INTO THE LAKES. KEPT TEMPERATURES PRETTY SIMILAR TO
GOING FORECAST EXCEPT WARMED UP LOWS A BIT TONIGHT WITH PLENTY OF
CLOUDS IN THE AREA...TEMPERATURES SHOULD BE FAIRLY UNIFORM WITH
COOLEST READINGS NEAR LAKE MICHIGAN.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 358 PM EDT SUN MAY 24 2015

IN THE UPPER LEVELS...TROUGH OVER THE WESTERN CONUS LIFTS ACROSS THE
NORTHERN PLAINS AND UPPER GREAT LAKES EARLY THIS WEEK AS ADDITIONAL
TROUGHING MOVES OVER NORTHWEST CONUS. BY LATE IN THE WEEK...NW CONUS
TROUGH MOVES EAST AND MERGES WITH DEEPER TROUGH MOVING FM CNTRL
CANADA OVER THE GREAT LAKES. AT THE SFC...LOW PRESSURE SYSTEM OVER
LK SUPERIOR ON MONDAY NIGHT WILL DRAG A TROUGH ACROSS UPPER LAKES ON
TUESDAY AS IT MOVES TO QUEBEC. MOST RAIN WILL BE DONE BY 00Z TUESDAY
AS DRY SLOT MOVES IN FM THE SOUTH IN WAKE OF SHORTWAVE AND SFC LOW
MOVING THROUGH. TRACK OF SFC LOW STILL UNCERTAIN...BUT SEEMS IT WILL
BE SOMEWHERE OVER CNTRL OR EASTERN LK SUPERIOR...COMPARED TO FARTHER
WEST TRACK MODELS WERE PREVIOUSLY INDICATING. RESULT WILL BE TO KEEP
EASTERLY COMPONENT WIND OVER THE KEWEENAW INTO THE EVENING AND THUS
A BETTER CHANCE OF FOG OR EVEN SOME DRIZZLE. SSW-SW WINDS ELSEWHERE
WILL LIMIT MOST OF THE FOG VCNTY OF LAKE MICHIGAN SHORE.

NEXT BETTER CHANCES OF RAIN ARRIVE LATER IN THE DAY ON TUESDAY AS
MODELS INDICATE SHORTWAVES CURRENTLY OVER FAR SOUTHERN CA AND IN THE
VCNTY OF UPPER LOW CENTER OVER INTERMOUNTAIN WEST COMBINE TO LIFT
ACROSS UPPER GREAT LAKES. MAY EVEN BE STRONG ENOUGH SYSTEM TO HELP
DEVELOP A SFC LOW PRESSURE. HEAVIEST QPF WILL BE ALONG AND WEST OF
H85-H7 LOWS...WHICH IS NOT QUITE CLEAR. GFS FAVORS FAR WESTERN UPR
MICHIGAN WHILE GEM-NH AND ECMWF ARE MORE OVER CNTRL UPR MICHIGAN.
ELEVATED INSTABILITY PRESENT WITH MUCAPES OF AT LEAST 300 J/KG ECMWF
OR UP OVER 1000J/KG AS THIS WAVE LIFTS THROUGH...SO DID INCLUDE TSRA
MENTION ON TUE/TUE NIGHT. IF FARTHER WEST TRACK VERIFIES...POTENTIAL
IS THERE FOR SFC BASED TSRA TUE AFTN INTO TUE EVENING. MAX TEMPS ON
TUESDAY AHEAD OF THE SYSTEM SHOULD BE ABLE TO REACH 70S INLAND WEST.
HOWEVER...EAST WINDS CLOSER TO LK SUPERIOR AND SOUTH WINDS CLOSER TO
LK MICHIGAN WILL KEEP IT COOLEST IN THOSE AREAS DUE TO ONSHORE FLOW
AND ALSO LINGERING FOG AND LOW CLOUDS.

LOW PRESSURE SYSTEM OR TROUGH SHOULD BE EAST OF UPPER LAKES BY WED.
COULD BE WEAKER WAVE ALOFT MOVING THROUGH THAT INTERACTS WITH SOME
AFTN HEATING TO PRODUCE ISOLD SHRA OR EVEN TSRA...MAINLY WEST. GEM-
NH AND ECMWF HINTING AT THIS...SO KEEP SLIGHT CHANCES EVEN THOUGH
GFS FAVORS DRY CONDITIONS. LIGHTER WEST WINDS WILL ONLY BE LOCALLY
ONSHORE...SO MOST AREAS SHOULD WARM WELL INTO THE 70S AS H85 TEMPS
CLIMB INTO THE LOWER TEENS C.

TROUGH ALOFT SETTLES OVER UPR LAKES ON THURSDAY WHILE MORE ORGANIZED
AREA OF LOW PRESSURE DEVELOPS OVER THE NORTHERN PLAINS AS THE
SHORTWAVE TROUGH MOVES EAST FM THE NORTHWEST CONUS. SFC LOW AND
TROUGH WILL EDGE ACROSS UPPER MISSISSIPPI RIVER VALLEY ON THURSDAY
THEN SLIDE OVER THE UPPER GREAT LAKES FRIDAY INTO FRIDAY NIGHT. THE
TROUGH WILL THEN BE SHOVED SOUTH OVER THE LOWER GREAT LAKES AND OHIO
VALLEY BY NEXT WEEKEND AS CANADIAN HIGH PRESSURE BUILDS OVER THE
NORTHERN PLAINS AND UPR GREAT LAKES. BEST SHOT OF SHRA AND POSSIBLE
TSRA ARRIVES FOR THURSDAY NIGHT OVER THE WEST THEN OVER ALL OF CWA
ON FRIDAY AS THE UPPER AND SFC COLD FRONT SWEEP THROUGH. MODELS ALL
HAVE THE GENERAL IDEA OF COLD FRONTAL PASSAGE...BUT VARY ON WHEN
PASSAGE OCCURS. GFS IS QUICKEST WITH MOST OF AREA DRY BY FRIDAY
AFTN. ECMWF AND GEM-NH ARE SLOWER...BRINGING THE FRONT THROUGH ON
FRIDAY OR EVEN FRIDAY NIGHT. NO MATTER WHICH SOLUTION IS
PREFERRED...APPEARS COOL AND DRY CONDITIONS ARE ON THE WAY NEXT
WEEKEND AS HIGH PRESSURE BUILDS OVERHEAD.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 135 PM EDT SUN MAY 24 2015

ALTHOUGH THERE WILL BE AN INCREASE IN MID AND HIGH CLOUDS...DRY AIR
WILL LINGER AT THE LOWER LEVELS THROUGH AT LEAST INTO EARLY THIS
EVENING...RESULTING IN VFR CONDITIONS AT KIWD/KCMX/KSAW. BY LATE
THIS EVENING...AN AREA OF SHOWERS WILL LIFT N INTO THE UPPER GREAT
LAKES...BRINGING DETERIORATING CONDITIONS AT ALL SITES. CONDITIONS
WILL FALL TO IFR OR LOWER AT ALL TERMINALS LATE TONIGHT. IFR/LIFR
CONDITIONS WILL THEN PERSIST THROUGH MONDAY MORNING. MOIST ERLY
UPSLOPE FLOW OFF OF LAKE INTO CMX MAY DROP VSBY DOWN TOWARD VLIFR
MON MORNING BUT WITH RAIN PREVAILING...NOT CONFIDENT IN LOWERING VSBY
BELOW 1SM YET.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 PM EDT SUN MAY 24 2015

LIGHT WINDS INCREASE ON MONDAY AS LOW PRESSURE SYSTEM OVER THE
CENTRAL PLAINS LIFTS TOWARD LK SUPERIOR. EAST WINDS MAY REACH 25
KTS...STRONGEST OVER WESTERN LK SUPERIOR. LOW SLIDES OVERHEAD ON
MONDAY NIGHT SO THE WINDS WILL DIMINISH. WINDS THE REST OF THE
FORECAST PERIOD ARE EXPECTED TO STAY AT OR BLO 20 KTS. FOG IS
EXPECTED TO DEVELOP LATE TONIGHT AND IT SHOULD LINGER THROUGH
WEDNESDAY. THE FOG MAY BE DENSE AT TIMES. ONCE IT IS EVIDENT
HOW EXPANSIVE THE FOG IS...A DENSE FOG ADVISORY MAY BE NEEDED.
&&

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

$$

SHORT TERM...07
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA



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