Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 240529
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1229 AM CDT SUN APR 24 2016

.UPDATE...
ISSUED AT 915 PM CDT SAT APR 23 2016

ADJUSTED POPS OVERNIGHT TO FOCUS RAIN CHANCES TO THE SOUTHERN HALF
OF THE FORECAST AREA. THIS IS CONFIRMED BY THE LATEST SHORT TERM
HIRES MODELS.

UPDATE ISSUED AT 727 PM CDT SAT APR 23 2016

BOOSTED POPS ACROSS THE SOUTHERN ZONES FOR THIS EVENING WHERE
BEST FRONTOGENESIS IS OCCURRING. THIS FRONTOGENESIS EXTENDS FROM
THE SFC UP TO 700MB. SOME THUNDERSTORMS WERE OCCURRING OVER
SOUTHERN CASS COUNTY. HAVE MADE OTHER ADJUSTMENTS AS WELL.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM CDT SAT APR 23 2016

AT 330 PM...AN UPPER LEVEL LOW WAS OVER THE IDAHO/UTAH/WYOMING
BORDER AREA. AN ASSOCIATED SURFACE LOW WAS NEAR THE BORDER BETWEEN
WYOMING AND SOUTH DAKOTA. MUCH OF THE UPPER MIDWEST HAD WARM
SOUTHERLY FLOW AND MOSTLY CLEAR SKIES...BUT AREAS FARTHER
NORTH...INCLUDING NORTHERN MINNESOTA AND THE LAKE SUPERIOR
REGION...HAD CLOUDIER SKIES AND COOL EASTERLY FLOW. THERE WAS A
BAND OF SHOWERS ACROSS THE NORTHERN FORECAST AREA...WHICH WAS
ASSOCIATED WITH A BAND OF LOW/MID LEVEL FRONTOGENESIS.
TEMPERATURES RANGED FROM THE LOWER 60S ACROSS THE SOUTHERN
FORECAST AREA...TO THE 40S AND 50S ACROSS THE NORTHERN FORECAST
AREA AND NEAR LAKE SUPERIOR IN NW WISCONSIN.

THE LOW IN THE HIGH PLAINS WILL GRADUALLY MOVE EAST THROUGH SOUTH
DAKOTA TONIGHT AND SUNDAY. THE APPROACHING SYSTEM WILL BRING A
SURGE OF MOISTURE INTO THE NORTHLAND THROUGH SUNDAY...WITH
PRECIPITABLE WATER VALUES INCREASING FROM ABOUT ONE HALF INCH TO
OVER ONE INCH. A COMBINATION OF SHORTWAVES AND FRONTOGENETICAL
BANDS WILL BRING INCREASING CHANCES OF RAIN SHOWERS OVERNIGHT INTO
SUNDAY...PRIMARILY FOR THE SOUTHERN TWO THIRDS OF THE FORECAST
AREA. THE RAP/NAM12/SREF/GFS ALSO INDICATE THERE COULD BE UP TO A
FEW HUNDRED J/KG OF MUCAPE ACROSS THE FAR SOUTHERN FORECAST AREA
TO RESULT IN WEAK THUNDERSTORMS TONIGHT. A WIDESPREAD QUARTER TO
THREE QUARTERS OF AN INCH OF RAINFALL IS FORECAST BY EARLY SUNDAY
EVENING. SOME PARTS OF NW WISCONSIN COULD GET MORE THAN 1 INCH.
THE RAINS WILL CONTINUE BEYOND THE SHORT TERM PERIOD...ALL THE WAY
THROUGH MONDAY...WITH WIDESPREAD RAINFALL OF 1 TO NEARLY 3 INCHES
OF TOTAL RAINFALL FORECAST FROM NOW THROUGH MONDAY EVENING.

THE PCPN TYPE THROUGH SUNDAY SHOULD MAINLY BE RAIN.
HOWEVER...THERE COULD BE A MIXTURE OF RAIN AND SNOW OVER THE
HIGHER TERRAIN OF THE ARROWHEAD TONIGHT AND EARLY SUNDAY. THERE
SHOULD BE LITTLE IF ANY SNOW ACCUMULATION BECAUSE OF MELTING.

STRONG ENE TO NE FLOW WILL DEVELOP OVER WESTERN LAKE SUPERIOR
TONIGHT AND SUNDAY...RESULTING IN GUSTY WINDS DOWNWIND ACROSS NE
MINNESOTA AND NW WISCONSIN. THE TWIN PORTS AREA COULD GET GUSTS TO
AROUND 30 MPH. THE EXPOSED BLATNIK AND BONG BRIDGES COULD GET
GUSTS OVER 40 MPH SUNDAY.

THE CLOUD COVER...RAIN...AND FLOW FROM LAKE SUPERIOR WILL PROVIDE
THE NORTHLAND WITH MUCH COOLER WEATHER THAN SEASONAL NORMALS
SUNDAY. ONLY UPPER 30S ARE FORECAST AROUND LAKE SUPERIOR...BUT
AREAS WELL INLAND SHOULD REACH THE 40S. HIGH PRESSURE OVER
CANADA...AND DRIER FLOW FROM ONTARIO...WILL HELP SOME PARTS OF THE
FAR NW FORECAST AREA REACH AROUND 50 DEGREES.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM CDT SAT APR 23 2016

FOCUS IN LONG TERM IS ON WARM FRONT POSITION AND RAINFALL AMOUNTS
THROUGH MONDAY. NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST WITH
GOOD MODEL AGREEMENT THAT THE THERMAL BOUNDARY STALLS ACROSS THE
CENTRAL PORTIONS OF MINNESOTA AND WISCONSIN SUNDAY NIGHT. THIS
WILL FOCUS THE HEAVY RAIN ON THE NORTH SIDE OF THE BOUNDARY ACROSS
NORTHERN WISCONSIN...EXTENDING NORTH INTO THE TWIN PORTS TO
BRAINERD LAKES REGION. THERE WILL BE AN ABRUPT CUT-OFF TO THE
PRECIPITATION ALONG THE IRON RANGE AND MN ARROWHEAD ZONES AS MUCH
DRIER AIR ASSOCIATED WITH HIGH PRESSURE IN CANADA SINKS INTO THE
NORTHERN ZONES. HAVE REMOVED MENTION OF SNOW SHOWERS SUNDAY
NIGHT/MONDAY AS MID LEVELS REMAIN ABOVE FREEZING WHERE THE
PRECIPITATION IS EXPECTED.

RAINFALL AMOUNTS WILL BE SIGNIFICANT...WITH THE GREATEST TOTALS
ON THE ORDER OF 2-3" INCHES CAN BE EXPECTED FROM THE TWIN
PORTS...OVER NORTHERN WISCONSIN THROUGH MONDAY. LOCALIZED URBAN
FLOODING WILL BE POSSIBLE.

THE STRONG PRESSURE GRADIENT WILL ALLOW FOR GALE FORCE WINDS OVER
LAKE SUPERIOR. LATEST NAM/ECM/GFS ARE ALL SHOWING A PERIOD OF
925HPA WINDS ON THE ORDER OF 50KNOTS ACROSS THE WESTERN PORTION OF
LAKE SUPERIOR AND INTO THE TWIN PORTS LATE SUNDAY NIGHT INTO
MONDAY MORNING. A GALE WARNING IS IN EFFECT FOR WESTERN LAKE
SUPERIOR DURING THIS TIME. LOCATIONS NEAR THE LAKE CAN EXPECT
WINDS GUSTING OVER 40 MPH AT TIMES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1225 AM CDT SUN APR 24 2016

RAIN WILL AFFECT ALL TERMINALS THROUGH THE FORECAST. THE
EXCEPTION IS INL WHERE THE RAIN SHOULD END BY 15Z/10AM AS HIGH
PRESSURE ARRIVES AND CIGS IMPROVE TO VFR. CIGS ARE FORECAST TO DROP
INTO THE MVFR AND EVENTUALLY THE IFR RANGE THROUGH THE 10-14Z TIME
RANGE. GUSTY SFC WINDS ARE EXPECTED THROUGH MUCH OF THE FORECAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  35  38  32  35 /  90  90  90  70
INL  34  51  31  49 /  90  10  10  10
BRD  44  46  36  43 /  90  80  90  70
HYR  43  51  38  42 /  90  80  90  80
ASX  38  41  37  38 /  80  90  90  80

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LSZ121-
     142>148.

     GALE WARNING FROM 10 AM THIS MORNING TO 7 PM CDT MONDAY FOR
     LSZ121-140>148.

&&

$$

UPDATE...GSF
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...LE



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