Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 202013
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
413 PM EDT MON OCT 20 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 412 PM EDT MON OCT 20 2014

WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
THE CANADIAN MARITIMES INTO THE CNTRL GREAT LAKES AND A RIDGE OVER
THE WRN PLAINS RESULTING IN NNW FLOW THROUGH THE THE WRN LAKES. AT
THE SFC...NNW WINDS PREVAILED BTWN LOW PRES OVER NRN LAKE HURON AND
HIGH PRES OVER NW ONTARIO. THE COMBINATION OF ABUNDANT SFC-800 MB
MOISTURE...CYCLONIC AND UPSLOPE NRLY FLOW AND 850 MB TEMPS AROUND
-1C (LAKE WATER TEMPS STILL NEAR 8C-9C) WAS ENOUGH TO SUPPORT SOME
SCT LIGHT SHOWERS OR SPRINKLES INTO W AND N CNTRL UPPER MI.

TONIGHT...UPSTREAM OBS MDLS SUGGEST LOW LEVEL MOISTURE WILL PERSIST
AS 850 MB TEMPS FALL TO NEAR -4C...HELPING TO SUSTAIN SOME LIGHT
PCPN. AS THE NW ONTARIO HIGH BUILDS TO THE SE...VEERING WINDS TO
NNE WILL SHIFT THE REMAINING LAKE ENHANCED SHOWERS MAINLY INTO N
CNTRL UPPER MI...WHERE UPSLOPE FLOW IS MAXIMIZED. EVEN THOUGH
WET-BULB ZERO HEIGHTS FALL BELOW 500 FT AGL...EXPECT THAT THE LAKE
OF ICE NUCLEI IN THE MOIST LAYER THAT ONLY EXTENDS TO NEAR
-5C...WILL NOT SUPPORT SNOW. CLOUDS WILL LINGER OVER MOST OF THE
AREA...KEEPING MIN READINGS IN THE MID TO UPPER 30S. HOWEVER...THERE
MAY BE SOME CLEARING OVER THE EAST WITH DOWNSLOPE FLOW FROM ONTARIO E
OF LAKE SUPERIOR.

TUE...THE LINGERING 2K-3K FT LOW LEVEL INVERSION WILL KEEP
MOISTURE/CLOUDS TRAPPED INTO THE MORNING...ESPECIALLY DOWNSTREAM OF
MOISTENING OFF OF LAKE SUPERIOR. BY AFTERNOON...EXPECT ENOUGH
HEATING/MIXING AND DRY ADVECTION TO BRING DIMINISHING CLOUDS THAT
WILL PUSH TEMPS INTO THE UPPER 40S OVER THE S AND WEST WHILE LOWER
READINGS IN THE LOW 40S PREVAIL OVER THE NORTH.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 357 PM EDT MON OCT 20 2014

TUESDAY NIGHT THROUGH WEDNESDAY EVENING WILL BE DRY FOR THE UPPER
GREAT LAKES...AS THE 500MB TROUGH OVERHEAD TODAY DIGS INTO THE NE
U.S. THIS WILL SET UP RIDGING AT THE SFC AND ALOFT FOR THE UPPER
GREAT LAKES...WITH SLOWLY MODIFYING AFTERNOON TEMPERATURES. THE MAIN
CONCERN FOR THOSE WITH SENSITIVE OUTDOOR PLANTS STILL WILL BE
MORNING LOWS TUESDAY MORNING...WHICH WILL FALL AT OR BELOW 32F FOR
MUCH OF THE CWA EXCLUDING THE TIP OF THE KEWEENAW PENINSULA.

THURSDAY...MODELS HAVE COME IN A BIT WETTER FOR THE
THURSDAY-THURSDAY EVENING TIME PERIOD AS THE NEXT SHORTWAVE DIGS
ACROSS ONTARIO AND MN DURING THE DAY. WHILE THE MAIN SFC LOW WILL
STILL BE OVER W CANADA AT THAT TIME...A SFC TROUGH OVER MANITOBA AND
NW MN THURSDAY MORNING WILL NEAR THE REGION. WITH UPPER MI STUCK IN
THE AREA OF HIGH PRESSURE IN BETWEEN THE DEEPENING LOW OFF THE NE
COAST...AND THE CANADIAN LOW. LIMITED E PROGRESS OF SHOWERS IS STILL
EXPECTED...ALTHOUGH POPS WERE INCREASED SLIGHTLY FOR THE W...AND
WERE EXTENDED INTO THE EVENING HOURS. THE 12Z GFS AND ECMWF BACK
THIS SOLUTION.

LOOK FOR THE 500MB WAVE TO PUSH E OF LAKE SUPERIOR FRIDAY
AFTERNOON...WITH ANY LINGERING LIGHT SHOWERS ENDING. THE W CANADIAN
SFC LOW-500MB LOW WILL SHIFT INTO NE MANITOBA OVERNIGHT...WITH WARM
AIR SURGING INTO UPPER MI. 850MB TEMPS OF 8-12C LOOK REASONABLE
FRIDAY NIGHT ON WSW WINDS...WITH SFC TEMPS BOTTOMING OUT IN THE 40S.

SATURDAY/SATURDAY NIGHT WILL BE OUR TRANSITION PERIOD...AS ZONAL
FLOW SLIDES IN ALOFT...AND THE SFC RIDGE EXITS TO THE LOWER GREAT
LAKES. THERE IS SOME DISCREPANCIES IN THE FCST GUIDANCE...SHOWING UP
ON THE IDEA OF HOW MUCH COLD AIR WILL BE ABLE TO SNEAK IN FROM THE
NW. THE 20/00Z RUN OF THE ECMWF HAS 850MB TEMPS AROUND 2C AT 00Z
SUNDAY...WHILE THE 20/12Z IS AT A MUCH MORE MILD 7C. WILL KEEP WITH
A MORE BLENDED SOLUTION FOR THE FCST STILL AT THIS POINT.

SUNDAY THROUGH MONDAY WILL BRING ABOUT A RETURN OF THE 500MB
RIDGE...EXTENDING FROM THE GULF OF MEXICO THROUGH ONTARIO. THIS
RIDGE WILL SLOWLY EXIT TOWARD THE NEW ENGLAND STATES ON MONDAY AS A
TROUGH SETTLES ACROSS THE CENTRAL PLAINS AND NEARS THE GREAT LAKES
REGION...WITH A GOOD CHANCE OF WET WEATHER LATE SUNDAY INTO MONDAY
OF NEXT WEEK...WITH TEMPS REMAINING ABOVE NORMAL.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 150 PM EDT MON OCT 20 2014

EXPECT MVFR CIGS TO PREVAIL INTO TONIGHT...THOUGH A PERIOD OF IFR
CIGS SHOULD LINGER EARLY THIS AFTERNOON AT SAW. LAKE ENHANCED RAIN
SHOWERS WILL BE POSSIBLE...MAINLY THIS AFTERNOON AT KSAW. THE
PERSISTENT LOW LEVEL MOISTURE IS EXPECTED TO MOVE OUT OF WEST UPPER
MICHIGAN LATE TONIGHT BUT SHOULD LINGER INTO TUE MORNING AT SAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EDT MON OCT 20 2014

LOW PRESSURE OVER EASTERN LAKE SUPERIOR NEAR WHITEFISH POINT WILL
MOVE TOWARD THE LOWER GREAT LAKES THROUGH THE DAY AND INTO TONIGHT.
PRESSURE GRADIENT TIGHTENS BTWN THE EXITING LOW AND HIGH PRESSURE
RIDGE BUILDING OVER NORTHWEST ONTARIO. EXPECT NORTH TO NORTHEAST
WINDS INCREASING TO 25-30 KTS THIS AFTN INTO THIS EVENING OVER
CNTRL AND EASTERN LK SUPERIOR. WINDS WILL DIMINISH TUESDAY MORNING
AS THE HIGH PRESSURE RIDGE SETTLES ACROSS LK SUPERIOR. WINDS SHOULD
REMAIN LESS THAN 20 KTS FOR THE REST OF THE WEEK...WITH STRONGER
WEST TO NORTHWEST WINDS UP TO 30 KTS POSSIBLE ON SATURDAY AS A LOW
PRESSURE SYSTEM CROSSES NORTHERN ONTARIO.
&&

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

$$

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





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