Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 210834
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
434 AM EDT THU MAY 21 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EDT THU MAY 21 2015

THE NEARING COLD FRONT/SFC TROUGH WILL BE A POSITIVE OVER THE
KEWEENAW PENINSULA...MOISTENING UP THE LOWER LEVELS BY SHIFTING
COOLER AIR INLAND FROM LAKE SUPERIOR. AT 3AM IT WAS 59F AT P59 WITH
28 PERCENT RH. THIS POOR RH RECOVERY HAS BEEN THE TREND ACROSS MUCH
OF THE W AND CENTRAL UP...BUT ESPECIALLY THE KEWEENAW PENINSULA AND
DOWNSLOPE AREAS NEAR LAKE SUPERIOR. ON THE OPPOSITE END OF THE
SPECTRUM...ISQ HAS BEEN IN THE FOG...WITH VIS DOWN TO 3/4SM SHORTLY
AFTER 3AM.

THE MAIN QUESTION TODAY WILL BE IF SHOWERS WILL BE ABLE TO DEVELOP S
CENTRAL THIS AFTERNOON ALONG THE E-W ORIENTED COLD FRONT/SFC
BOUNDARY SINKING ACROSS MOST OF THE CWA THIS MORNING...AND S CENTRAL
EARLY THIS AFTERNOON. FCST MODELS HAVE BEEN VERY CONSISTENT OVER THE
PAST COUPLE OF DAYS ON HAVING PRECIP ACROSS NE WI /ASSOCIATED WITH
PEAK HEATING AND LAKESHORE BOUNDARIES/. MUCH OF MENOMINEE COUNTY
LOOKS TO GET CLIPPED WITH LESS THAN 0.1IN. WOULD NOT BE SUPRISED IF
S MENOMINEE COUNTY POPS NEED TO BE INCREASED. WILL CONTINUE TO
MONITOR THE 06Z MODEL RUNS AS THEY COME IN...AND ADJUST AS NEEDED.

OTHERWISE...DRY AIR WILL BE UPON US. RH VALUES WILL FALL TO 25 TO 30
PERCENT IN THE TRADITIONAL LOCATIONS INLAND FROM THE COOLER N TO NW
AIR OFF LAKE SUPERIOR. THE STRONGEST WINDS WILL BE OVER THE E HALF
OF UPPER MI...WITH FUNNELING NW WINDS INCREASING GUSTS TO 20-25KTS
NEAR THE SOO. IT WILL BE ANOTHER COOL/DRY NIGHT AS THE NEXT ROUND OF
HIGH PRESSURE BUILDS IN FROM THE NW. TEMPERATURES SHOULD BOTTOM OUT
IN THE MID 20S TO MID 30S. WILL MENTION A FROST POTENTIAL INLAND
FROM THE GREAT LAKES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 404 PM EDT WED MAY 20 2015

NORTHWESTERLY CONFLUENT FLOW ALOFT ON WESTERN EDGE OF TROUGH
CENTERED ON EASTERN CANADA PERSISTS THROUGH THE WEEKEND...SO SFC
HIGH PRESSURE WILL BE THE MAIN WEATHER FEATURE. TROUGH ALOFT STAYS
OVER WESTERN HALF OF CONUS WHICH KEEPS MAIN SFC LOW AND WARM FRONT
OVER CENTRAL PLAINS. WEAK COLD FRONT DROPS FROM NORTHERN ONTARIO ON
SATURDAY TO THE UPPER GREAT LAKES ON SUNDAY. APPEARS TROUGH ALOFT
WILL TRY TO BRIEFLY LIFT TOWARD GREAT LAKES EARLY NEXT WEEK WHICH
BRINGS SFC LOW AND WARM FRONT CLOSE ENOUGH TO SUPPORT INCREASING
CHANCES OF RAIN. ADDITIONAL FOCUS FOR RAIN MAY ALSO COME VIA YET
ANOTHER NORTHERN STREAM SHORTWAVE AND COLD FRONT THAT CLOSES IN ON
UPPER GREAT LAKES TUESDAY INTO WEDNESDAY.

EXPECT MINIMAL HIGH IMPACT WEATHER ISSUES THROUGH THE LONG TERM.
LINGERING DRY AIRMASS WILL RESULT IN ANOTHER CHILLY NIGHT ON
THURSDAY NIGHT WITH TEMPS AGAIN FALLING BLO FREEZING INLAND. DRY
AIRMASS THEN RESULTS IN LOWER MIN HUMIDITY VALUES FOR FRIDAY AFTN
WITH H85 DWPT DEPRESSIONS OVER 20C. WINDS LESS THAN 15 MPH WITH THE
HIGH OVERHEAD AND ONGOING GREEN UP COMBINE TO MITIGATE FIRE WEATHER
ISSUES.

NOT AS CHILLY FRIDAY NIGHT AS WEST WINDS START TO STIR AHEAD OF WEST
TO EAST ORIENTED FRONT DROPPING OVER NORTHERN ONTARIO. STRONGER WEST
WINDS EXPECTED ON SATURDAY. WINDS/GUSTS ON LAND SHOULD STAY BLO 25
MPH...BUT MAY HAVE A FEW SMALL CRAFT ADVISORIES TO DEAL WITH FOR
START OF THE MEMORIAL DAY WEEKEND. TEMPS ON SATURDAY SHOULD BE ABLE
TO REACH WELL INTO 70S IN MANY AREAS AS WEST-SOUTHWEST WINDS
MINIMIZE LAKE BREEEZES FOR ALL BUT KEWEENAW AND NEAR LK MICHIGAN.
HUMIDITY VALUES NOT AS LOW AS FRIDAY...BUT COULD SEE RH DOWN TO 25-
30 PCT OVER INLAND LOCATIONS. WILL HAVE TO KEEP MONITORING SATURDAY
BECAUSE IF WINDS END UP STRONGER OR MIN RH LOWER THAT DAY COULD END
UP WITH NEAR CRITICAL FIRE WEATHER CONDITIONS IN SOME AREAS.

INCREASING MID-LEVEL RH TO THE NORTH OF WARM FRONT COULD TRIGGER
SHOWERS SATURDAY NIGHT INTO SUNDAY FM WI OVER UPR MICHIGAN...BUT
CHANCES LOOK SLIM GIVEN MINIMAL INSTABILITY OR LARGER SCALE
LIFT...BOTH OF WHICH STAY TO THE SOUTHWEST OF UPPER GREAT LAKES.
STRONGEST MOISTURE TRANSPORT FM H85-H7 REMAINS SOUTH OF HERE SO THAT
ALSO SUGGESTS LOW CHANCES OF SHOWERS OVER UPR MICHIGAN. DID NOTICE
THAT 12Z GFS AND NAM INCREASE THIN LAYER OF MID LEVEL RH ON SATURDAY
AFTN. GFS TRIES TO SHOW QPF OVER AREA WHICH SEEMS WAY OVERDONE GIVEN
SHALLOWNESS OF THE MOIST LAYER. WILL KEEP IT DRY ON SATURDAY AND
BRING IN LOW CHANCES LATER SATURDAY NIGHT INTO SUNDAY. MODELS REMAIN
IN DISAGREEMENT ON FORECAST FOR SUNDAY. LAST FEW RUNS OF GFS STILL
PERSISTENT IN BRINGING SFC LOW AND WARM FRONT FARTHER NORTH AND SHOW
WIDESPREAD QPF OVR UPR MICHIGAN ON SUNDAY. ECMWF AND GEM-NH
SLOWER...BRINGING QPF IN LATER SUNDAY NIGHT OR EVEN ON MONDAY.
BLOCKY/SLOW PROGRESSION OF UPPER LEVEL PATTERN WOULD FAVOR SLOWER
ARRIVAL OF MAIN SHOWERS IN WARM AND MOIST ADVECTION ALOFT OVER THE
UPR GREAT LAKES...BUT WILL KEEP LOW CHANCES SHOWN BY CONSENSUS WITH
A NOD TO THE PERSISTENT GFS. EVEN BY MONDAY WHEN CHANCES INCREASE
FURTHER ON ALL MODELS...LEFT OUT TSRA AS ECMWF/GFS INDICATE MINIMAL
MLCAPES OR EVEN ELEVATED MUCAPES. GREATER RISK SHOULD BE ALONG AND
SOUTH OF THE WARM FRONT...WHICH DOES NOT SEEM TO MAKE IT AS FAR
NORTH AS UPPER GREAT LAKES.

AS FAR AS TEMPS GO...NO SIGNIFICANT WARMING OR COOLING BEYOND
SATURDAY. OVERALL THE TEMPS SHOULD END UP PRETTY CLOSE TO NORMAL.
ONLY THING THAT WOULD LEAD TO COOLER TEMPS IS IF IT ENDS UP CLOUDIER
WITH MORE RAIN FOR ANY OF THE DAYS SUNDAY THROUGH WEDNESDAY. SUPPOSE
ONE OF THOSE DAYS COULD SEE THAT KIND OF SETUP AND BEING NORTH OF
THE WARM FRONT WOULD HAVE THE ADDED ISSUE OF WINDS OFF THE GREAT
LAKES LEADING TO COOLER TEMPS. NO CONFIDENCE ON THOSE TYPE OF
DETAILS NOW THOUGH.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1205 AM EDT THU MAY 21 2015

A COLD FRONT WILL DROP S ACROSS UPPER MI THIS MORNING...BRINGING A
WSHFT TO A N TO NW DIRECTION. DESPITE FRONT APPROACHING AND THEN
PASSING...A DRY AIR MASS WILL PERSIST AT LOW LEVELS...RESULTING IN
VFR CONDITIONS PREVAILING AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
WINDS BEHIND THE FRONT TODAY WILL BE GUSTY AT KSAW DUE TO FAVORABLE
N WIND ENHANCED BY LAKE BREEZE.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EDT THU MAY 21 2015

SW WINDS WITH GUSTS NEARING 30KTS WILL REMAIN POSSIBLE OVER THE W
HALF OF LAKE SUPERIOR EARLY THIS MORNING. A TROUGH ACROSS S LAKE
SUPERIOR WILL SINK TO CENTRAL LAKE MICHIGAN TODAY...AND THE OHIO
VALLEY OVERNIGHT...WITH NW WINDS OVER THE E THIRD OF LAKE SUPERIOR
GUSTING TO AROUND 25KTS THIS AFTERNOON INTO EARLY THIS EVENING. HIGH
PRESSURE OVER N MANITOBA THIS MORNING WILL SLOWLY SINK ACROSS THE
UPPER GREAT LAKES OVERNIGHT...AND EXIT TO THE OHIO VALLEY FRIDAY
NIGHT. THIS WILL LEAVE A RIDGE ACROSS LAKE SUPERIOR THROUGH SUNDAY.
EXPECT  LOW PRESSURE OVER THE CENTRAL AND SOUTHERN PLAINS SUNDAY
MORNING TO DEEPEN ACROSS S MN AND IA BY DAYBREAK MONDAY...AND W LAKE
SUPERIOR DURING THE DAYTIME HOURS MONDAY.
&&

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

$$

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



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