Area Forecast Discussion Issued At 12Z SOUNDINGS FMGRB/INL/MPX REMAIN QUITE DRY...BUT MOISTURE AND

Area Forecast Discussion

Issued by NWS Marquette, MI

000

FXUS63 KMQT 241947

AFDMQT

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MARQUETTE MI

347 PM EDT FRI APR 24 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)

ISSUED AT 241 PM EDT FRI APR 24 2015

FLOW ALOFT BRIEFLY HAS BECOME WESTERLY WHICH IS ALLOWING WARM

ADVECTION OCCURRING NORTH OF WEAK SFC WARM FRONT OVER SOUTHERN

MINNESOTA TO AFFECT FAR WESTERN GREAT LAKES. LOW-LEVELS BLO H85 PER

12Z SOUNDINGS FM GRB/INL/MPX REMAIN QUITE DRY...BUT MOISTURE AND

WARM ADVECTION MAINLY AT H7 IS DRIVING AREA OF SCT LIGHT SHOWERS

OVER NORTHWEST WI. EVEN SOME SNOW WAS REPORTED IN NORTHEAST

MINNESOTA EARLIER TODAY AS TEMPS WERE IN THE 30S AS THE PRECIP BEGAN.

BASED ON WHERE RAP/NAM SHOW NOSE OF H7 MOISTURE TRANSPORT INTO THIS

EVENING...SOME OF THE SHRA OVER NORTHWEST WI MAY CLIP SW UPR

MICHIGAN THROUGH MIDNIGHT. GREATEST CHANCES FM IRONWOOD TO IRON

RIVER. WEAK FORCING ALOFT AND PERSISTENT DRY LOW-LEVELS WILL

PROHIBIT THE PRECIP FM MAKING IT VERY FAR TO THE NORTH AND EAST OF

THOSE AREAS. LATEST HRRR MODEL RUNS ARE PICKING UP ON THIS...SHOWING

ANY SIMULATED REFLECTIVITY AT 1KM OF NOTE FADING AS IT MOVES INTO

SCNTRL UPR MICHIGAN. AS TEMPS COOL ENOUGH IN BLYR AFTER SUNSET...MAY

SEE RAIN TRY TO TURN TO SNOW BRIEFLY BEFORE THE WANING FORCING

ALLOWS THIS PRECIP TO END. NOT EXPECTING ANYTHING MORE THAN A

COATING OF SNOW ACCUMULATION IF IT OCCURS AT ALL. TEMPS TONIGHT WILL

BE COOLEST IN THE EAST /UPR TEENS TO LOW 20S/ CLOSER TO SFC HIGH AND

WHERE SKIES STAY MOSTLY CLEAR. ELSEWHERE EXPECT READINGS IN UPR 20S

TO MID 30S...WARMEST WEST.

MID CLOUDS GRADUALLY FADE AWAY ON SATURDAY AS SFC HIGH PRESSURE

BUILDS IN FM HUDSON BAY. NORTHERLY GRADIENT WINDS TIED INTO THE HIGH

WILL KEEP AREAS NEAR LK SUPERIOR SHORE STUCK IN THE 30S DESPITE THE

INCREASING SUNSHINE. WARMEST TEMPS INTO THE LOW 50S WILL BE ALONG WI

BORDER AND ALSO NEAR LK MICHIGAN WITH NORTH WINDS COMING OFF THE

LAND OF EAST HALF OF UPR MICHIGAN.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)

ISSUED AT 342 PM EDT FRI APR 24 2015

SAT NIGHT AND SUN...SFC RIDGING AND DRY WEATHER IS EXPECTED TO

DOMINATE THE WRN GREAT LAKES AS A MID LEVEL RIDGE BUILDS TOWARD MN

AND NW ONTARIO AND TROUGH LINGERS FROM NRN NEW ENGLAND THROUGH THE

ERN GREAT LAKES. WITH LIGHT NE TO N LOW LEVEL FLOW...TEMPS WILL

REMAIN BELOW NORMAL...ESPECIALLY NEAR LAKE SUPERIOR WHERE HIGHS WILL

REACH ONLY INTO THE LOWER 40S. READINGS TO AROUND 50 WILL PREVAIL

OVER THE SOUTH HALF.

THE SFC HIGH WILL CONTINUE TO RIDGE S INTO UPPER MI ON MON...SO MON

WILL BE SIMILAR TO SUN. HOWEVER...WITH THE PRES GRADIENT WEAKENING

AND A SLIGHT MODERATION OF AIR MASS...MAX TEMPS MON SHOULD BE

SEVERAL DEGREES HIGHER THAN SUN...ESPECIALLY IN THE INTERIOR.

MEDIUM RANGE MODELS INDICATE A SHORTWAVE MOVING ACROSS THE NRN

PLAINS MON NIGHT. AS MID/UPPER RIDGE BEGINS BUILDING OVER THE

ROCKIES...THIS WAVE MAY END UP DIVING SE OR S TOWARD A SRN TROF OVER

TX/LWR MISSISSIPPI VALLEY REGION PER 12Z RUNS OF GFS AND GEM AND

23/12Z ECMWF...RESULTING IN CONTINUED DRY WEATHER HERE. THE 24/00Z

AND 24/12Z RUNS OF THE ECMWF HAVE TRENDED STRONGER WITH THE

SHORTWAVE SHOWING A MORE AGGRESSIVE EASTWARD PROGRESSION BEFORE

DIVING THE SHORTWAVE SE. THIS SOLN MAY RESULT IN SOME LIGHT SHRA

SPREADING INTO UPPER MI TUE INTO WED MORNING. GIVEN THAT LATEST

ECMWF STILL SHOWS THE MORE AGGRESSIVE EASTWARD PROGRESSION WITH

SHORTWAVE WILL MAINTAIN SLIGHT CHC POPS FOR SHRA OVER THE CWA TUE

INTO WED. CAA IN N-NE FLOW AHEAD OF BUILDING SFC HIGH FM CANADA AS

DEPICTED BY 12Z ECMWF WL KEEP TEMPS COOLER WED INTO WED NIGHT

PROBABLY SIMILAR TO EXPECTED BELOW NORMAL READINGS THIS WEEKEND.

THU-FRI...SFC HIGH PRES BUILDS BACK OVER THE REGION AND SINCE BOTH

12Z GFS AND ECMWF HAVE TRENDED FARTHER NORTH WITH SERIES OF

SHORTWAVES MOVING ACROSS SCNTRL CANADA EXPECT GENERALLY DRY

CONDITIONS TO PREVAIL. GENERAL TREND OF 00Z MEDIUM RANGE GUIDANCE IS

FOR UPSTREAM MID-UPR LVL RIDGING OVER THE WRN CONUS TO BE A BIT MORE

PRONOUNCED WHICH RESULTS IN A SHARPER NW FLOW DEVELOPING INTO THE

UPPER LAKES. THIS WOULD TEMPER THE WARMUP INTO THE WRN GREAT LAKES

FOR LATE WEEK AND MAY RESULT IN TEMPS CLOSER TO NORMAL INSTEAD OF

ABOVE NORMAL.

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)

ISSUED AT 119 PM EDT FRI APR 24 2015

HIGH PRESSURE AND DRY CONDITIONS SHOULD REMAIN IN CONTROL OF ALL 3

TAF SITES THROUGH THE PERIOD...WITH VFR CEILINGS/VIS. THE ONLY SMALL

EXCEPTION WILL BE IWD LATE THIS AFTN INTO EARLY THIS EVENING...WHERE

SOME LIGHT SHRA MAY DROP CONDITIONS TO MVFR. WINDS WILL BE LIGHT

INTO SATURDAY.

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)

ISSUED AT 241 PM EDT FRI APR 24 2015

HIGH PRESSURE WILL BE THE DOMINANT WEATHER FACTOR OVER THE UPPER

GREAT LAKES THIS WEEKEND AND THROUGH MUCH OF NEXT WEEK. OVERALL THE

WINDS WILL STAY AT OR BLO 20 KTS. THE ONE MAIN EXCEPTION WILL BE

TONIGHT AND SATURDAY OVER WESTERN LK SUPERIOR WHERE EAST TO

NORTHEAST WINDS OF 20-25 KTS WITH GUSTS TO AROUND 30 KTS ARE

EXPECTED AS STRONGER HIGH PRESSURE AREA INITIALLY BUILDS OVER THE

REGION.

.MQT WATCHES/WARNINGS/ADVISORIES...

UPPER MICHIGAN...

NONE.

LAKE SUPERIOR...

NONE.

LAKE MICHIGAN...

NONE.

$$

SHORT TERM...JLA

LONG TERM...VOSS

AVIATION...JLA

MARINE...JLA

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