Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 192255
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
655 PM EDT SUN OCT 19 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 323 PM EDT SUN OCT 19 2014

THE CURRENT DISTURBANCE BRINGING SHOWERS TO THE AREA THIS AFTERNOON
WILL CONTINUE TO EXIT ACROSS THE E THIRD OF THE CWA THIS EVENING.
LOOKING UPSTREAM...A THICK LAYER OF IFR CEILING LOOKS TO BE IN STORE
FOR MUCH OF THE CWA OVERNIGHT. WILL CONTINUE TO FOLLOW A TREND
SIMILAR TO THE HRRR FOR TIMING...AS IT/S HAD A GOOD HANDLE ON THE
PRECIP SO FAR. RAIN AND SNOW SHOWERS HAVE BEEN REPORTED ACROSS N
ONTARIO AS WELL AS CENTRAL AND N MANITOBA. SNOW WILL NOT BE THE
LIKELY PRECIP TYPE ACROSS UPPER MI THROUGH...IF ANY PRECIPITATION
DOES FALL TONIGHT IT SHOULD BE ALL IN THE FORM OF SNOW. THIS IS
DISPUTE THE RETURN OF NNW FLOW BEHIND THE SFC LOW THAT WILL BE
SHIFTING OVERHEAD...MOVING FROM THE W THIRD OF THE CWA BY 00Z MONDAY
TO THE E HALF 06-12Z MONDAY. SFC TEMPS ARE EXPECTED TO BOTTOM OUT IN
THE LOW 40S.

AN ELONGATED AREA OF HIGH PRESSURE STRETCHING FROM HUDSON BAY
THROUGH MANITOBA AND W MN AT DAYBREAK MONDAY WILL SLOWLY INVADE
DURING THE DAYTIME HOURS....ALONG WITH A SERIES OF WAVES IN THE
N-NNW FLOW AT 500MB. FAVORABLE UPSLOPE NEAR SFC N-NNW WINDS
REMAINING ON MONDAY...AND PLENTY OF LOW LEVEL MOISTURE TRAPPED BELOW
850MB...AND COOL 850MB TEMPS AROUND -1C...WILL RESULT IN LIGHT
SHOWER/DRIZZLE ACTIVITY THROUGH THE DAY NEAR LAKE SUPERIOR. LAKE
ENHANCEMENT WILL REMAIN LIMITED DUE TO THE MARGINAL DELTA-T
VALUES...WITH LAKE SUPERIOR STILL AROUND 7C. TEMPS WILL NOT CLIMB
MUCH PAST THE MID TO UPPER 40S.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 PM EDT SUN OCT 19 2014

AS OPPOSED TO LAST WEEKS MOSTLY GLOOMY WET WEATHER...MOST DAYS THIS
WEEK WILL BE DRY AND WARMER WITH MORE SUNSHINE. IT`S LIKELY MANY
AREAS WON`T SEE ANY PCPN TUE THRU SUN. INITIALLY...AN AMPLIFYING
RIDGE OVER THE ROCKIES WILL SEND A SHORTWAVE DIVING SE THRU THE
GREAT LAKES TONIGHT AND MON. WAVE WILL THEN EVOLVE INTO A CLOSED LOW
OVER THE MID ATLANTIC STATES THRU THE MID WEEK PERIOD BEFORE
DRIFTING NE LATE WEEK. MEANWHILE...THE UPSTREAM RIDGE WILL SHIFT E
SO THAT A ZONE OF POSITIVE HEIGHT ANOMALIES WILL EXTEND FROM THE SRN
ROCKIES ACROSS THE UPPER LAKES INTO NRN QUEBEC DURING THE MID AND
LATE WEEK PERIOD...SUGGESTING A WARMER/DRIER PERIOD OF WEATHER.
SO...AFTER A COOL START TO THE WEEK...TEMPS WILL TREND ABOVE NORMAL
FOR THE LAST HALF OF THE WEEK. A SHORTWAVE TROF REACHING THE W COAST
MON WILL SHIFT E DURING THE WEEK...BUT WILL WEAKEN SUBSTANTIALLY AS
IT RUNS INTO THE RIDGE/POSITIVE ANOMALIES. SYSTEM MAY STILL GENERATE
A FEW SHRA IN THE UPPER LAKES THU. OVER THE UPCOMING WEEKEND...
UNCERTAINTY INCREASES IN WHETHER THE MID/UPPER LEVEL FLOW WILL
REMAIN A WARMER W TO SW OR SHIFT TO THE NW TO BRING A RETURN TO
COLDER CONDITIONS.

BEGINNING MON NIGHT....PRONOUNCED MID/UPPER LEVEL RIDGE WILL BE
SHIFTING OUT OVER THE PLAINS AND EXTENDING TO HUDSON BAY. AT THE
SFC...ASSOCIATED HIGH PRES CENTER WILL BE DRIFTING ACROSS NRN
ONTARIO WITH RIDGE EXTENDING SSW ACROSS WRN LAKE SUPERIOR INTO THE
UPPER MISSISSIPPI VALLEY BY 12Z TUE...BRINGING LARGER SCALE
ANTICYCLONIC FLOW. APPROACH OF THE RIDGE WILL RESULT IN LOWERING
INVERSION/DIMINISHING DEEP MOISTURE THRU THE NIGHT. BY 12Z...
INVERSION BASE WILL BE DOWN TO AROUND 3KFT OVER LAKE SUPERIOR. 850MB
TEMPS AROUND -2 TO -3C WILL BE MARGINAL AT BEST FOR LAKE EFFECT PCPN
DURING THE NIGHT AS THERE IS ONLY A NARROW ZONE OF WATER TEMPS NEAR
10C ALONG THE SRN SHORE OF LAKE SUPERIOR. OPEN WATER TEMPS ARE IN
THE 6-8C RANGE. FURTHER LIMITING PCPN POTENTIAL WILL BE DEEP LAYER
QVECTOR DIVERGENCE/SUBSIDENCE. ANY DAYTIME AIDED SHOWER ACTIVITY
WILL END DURING MON EVENING...AND AS WINDS VEER NORTHEASTERLY...ONLY
NCNTRL UPPER MI...AIDED BY UPSLOPE...WILL HAVE ANY CHC OF SEEING
SOME LIGHT PCPN LINGER INTO THE OVERNIGHT. POPS WILL BE KEPT LOW IN
THE SCHC/LOW CHC RANGE. AS THE DEEP MOISTURE PULLS OUT...LEAVING
TEMPS IN THE MOIST LAYER MUCH HIGHER THAN -10C...POTENTIAL FOR ICE
CRYSTALS IN THE CLOUD WILL BE VERY LOW...SO ONLY -SHRA WILL BE
MENTIONED IN FCST.

CLOUDS WILL DECREASE ON TUE...BUT MOST SLOWLY OVER THE CNTRL AS
ADDED MOISTURE FROM LAKE SUPERIOR COMBINED WITH DAYTIME HEATING WILL
HELP TO MAINTAIN A STRATOCU DECK LONGER.

TUE NIGHT SHOULD BE QUITE CHILLY UNDER CLEAR SKIES AND LIGHT/CALM
WIND ASSOCIATED WITH SFC HIGH PRES RIDGE OVER THE AREA. WITH
PRECIPITABLE WATER 35-55 PCT OF NORMAL...WENT WITH MIN TEMPS AT OR
BLO THE LOWEST GUIDANCE. 20S SHOULD BE COMMON IN THE INTERIOR.
A WARMER...SUNNY DAY WILL FOLLOW ON WED UNDER MID/UPPER LEVEL RIDGE
AXIS. ALL GUIDANCE APPEARS TOO COOL AS MIXING TO AROUND 900MB ON
FCST SOUNDINGS SUPPORTS MAX TEMPS AT LEAST INTO THE LWR 50S E AND
INTO THE UPPER 50S W.

TROF THAT MOVES ONSHORE OVER THE W COAST LATE MON WILL REACH THE
UPPER LAKES THU...BUT IN A SIGNIFICANTLY WEAKENED STATE. IN
ADDITION...MODELS SHOW ENERGY IN THE TROF SPLITTING WITH ONE PIECE
SETTLING SE THRU THE PLAINS AND THE OTHER PIECE LIFTING TO HUDSON
BAY. WITH SYSTEM CONTINUING TO WEAKEN...ONLY SCHC POPS WERE INCLUDED
OVER WRN UPPER MI THU.

A WARM DAY FOR LATE OCT SHOULD FOLLOW FOR FRI AS RIBBON OF
MOISTURE/CLOUDS ASSOCIATED WITH DECAYING TROF SHIFTS E OF THE
AREA...ALLOWING SKIES TO BECOME MOSTLY SUNNY. AT THIS POINT...IT
LOOKS LIKE FRI HAS THE BEST SHOT OF BEING THE WARMEST DAY OF THIS
FCST PERIOD UNDER SW FLOW. MANY LOCATIONS SHOULD REACH AT LEAST 60F
FOR MAX TEMPS ON FRI.

AS ALLUDED TO ABOVE...MODEL DIFFERENCES DEVELOP OVER THE UPCOMING
WEEKEND AS THE 00Z GFS/UKMET INDICATE MORE SUBSTANTIAL TROFFING
ARRIVING ALONG THE W COAST FRI...WHICH HELPS MAINTAIN MORE
RIDGING/WARMER CONDITIONS DOWNSTREAM INTO THE GREAT LAKES. THE 00Z
ECMWF/CMC HAVE THIS TROF FARTHER OFFSHORE. THIS RESULTS IN A FARTHER
W RIDGE AXIS WHICH THEN ALLOWS A SHORTWAVE TO DIVE MORE TO THE SE
INTO THE GREAT LAKES...BRINGING A SHOT OF COLDER AIR. THE 12Z RUNS
DIDN`T HELP CLARIFY THE ISSUE...BUT IT DOES APPEAR THE ECMWF MAY BE
A BIT TOO AGGRESSIVE WITH COOLING INTO THE UPPER LAKES. IN ANY
EVENT...WITH SHORTWAVE PASSING TO THE N OF THE AREA...PCPN POTENTIAL
LOOKS MINIMAL AT BEST...AND FOR NOW...FCST WILL REFLECT MODEST
COOLING OVER THE WEEKEND WITH TEMPS STILL ABOVE NORMAL.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 655 PM EDT SUN OCT 19 2014

VFR CONDITIONS INITIALLY WILL SLOWLY FALL TO MVFR AND EVEN POSSIBLY
IFR OVERNIGHT BEHIND LOW PRESSURE THAT WILL BE CROSSING OVERHEAD.
THIS WILL BRING ABOUT FAVORABLE NW FLOW...AND AS WHAT HAS ALREADY
BEEN SEEN UPSTREAM ACROSS MANITOBA AND ONTARIO...PLENTY OF LOW
CLOUDS. THE BEST CHANCE OF IFR CEILINGS WILL BE AT SAW AROUND
DAYBREAK WEDNESDAY...KEPT THEM AT MVFR FOR NOW GIVEN THE
UNCERTAINTY. COOL LAKE ENHANCED RAIN SHOWERS WILL BE POSSIBLE LATE
TONIGHT THROUGH MUCH OF THE DAY MONDAY.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 323 PM EDT SUN OCT 19 2014

LOW PRESSURE OVER W LAKE SUPERIOR WILL CROSS LAKE SUPERIOR
OVERNIGHT...AND EXIT ACROSS LAKE HURON ON MONDAY. HIGH PRESSURE OVER
EASTERN MANITOBA AND W MINNESOTA MONDAY AFTERNOON WILL BUILD ACROSS
ONTARIO/LAKE SUPERIOR MONDAY INTO TUESDAY. ANOTHER PERIOD OF MAINLY
N GUSTS TO 25KTS WILL BE POSSIBLE MONDAY AFTERNOON-EVENING OVER
CENTRAL AND E LAKE SUPERIOR. A RIDGE WILL LINGER ACROSS E LAKE
SUPERIOR INTO WEDNESDAY NIGHT AS THE MAIN AREA OF HIGH PRESSURE
BUILDS ACROSS QUEBEC. A RIDGE OF HIGH PRESSURE SHOULD LINGER INTO
FRIDAY...AS LAKE SUPERIOR GETS STUCK BETWEEN DEEPENING LOW PRESSURE
MOVING ACROSS NOVA SCOTIA...AND ANOTHER LOW NEARING FROM CENTRAL
CANADA.
&&

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

$$

SHORT TERM...KF
LONG TERM...ROLFSON
AVIATION...07
MARINE...KF





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