Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 030014 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
714 PM CDT TUE JUN 2 2015

.UPDATE...
ISSUED AT 714 PM CDT TUE JUN 2 2015

UPDATED AVIATION DISCUSSION FOR 00Z TAF ISSUANCE BELOW.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE JUN 2 2015

INCREASING CLOUDS WITH SHOWERS AND STORMS OVER THE SHORT TERM PERIOD
AS A COLD FRONT APPROACHES FROM THE WEST. GENERALLY WARMER TODAY
WITH HIGHS NEAR OR SLIGHTLY ABOVE NORMAL. MILD OVERNIGHT DUE TO
CLOUD COVER/PRECIP THEN NOT AS WARM ON WEDNESDAY FOR MOST BEHIND THE
COLD FRONT.

ON THE SYNOPTIC SCALE THERE IS WEST-NORTHWESTERLY ALOFT WITH A
SUBTLE SHORTWAVE TROUGH EMBEDDED IN THE FLOW RESULTING IN AN AREA OF
LARGE SCALE LIFT ACROSS NORTH-CENTRAL MINNESOTA ACROSS THE
BORDERLAND. A SFC LOW PRESSURE AND ACCOMPANYING FRONT WAS OVER THE
DAKOTAS AND WILL PROGRESS EASTWARD TODAY INTO TOMORROW. AT LOW
LEVELS WINDS WERE OUT OF THE SOUTH RESULTING IN WARM MOIST AIR BEING
ADVECTED INTO THE REGION AHEAD OF THE FRONT.

THIS MORNING CLOUDS AND SHOWERS MOVED ACROSS NORTH-CENTRAL MINNESOTA
MAINLY ACROSS ITASCA AND KOOCHICHING COUNTIES WITH PWAT VALUES OF
1.1 TO 1.3 INCHES RESULTING IN BRIEF PERIODS OF HEAVY RAIN. WITH
PRECIPITABLE WATER VALUES ONLY PROGGED TO INCREASED AHEAD OF THE FRONT
HEAVY RAIN WILL BE THE COMMON THEME LATER THIS AFTERNOON AND THROUGH
THE EVENING AS MORE SHOWERS AND STORMS DEVELOP. OTHERWISE MOSTLY
CLOUDY ACROSS NORTHEAST MINNESOTA THIS MORNING AND MAINLY SUNNY IN
NORTHWEST WISCONSIN...WITH AREAS OF WITH SUNNY SKIES ALREADY WARMING
UP TO THE 70S BY NOON.

FOR THE REST OF TODAY EXPECT CLOUD COVER TO INCREASE AS SFC
LOW/FRONT APPROACHES FROM THE WEST. AFTER AN AFTERNOON LULL PRECIP
COVERAGE WILL INCREASE THIS EVENING AND ESPECIALLY OVERNIGHT. EVEN
JUST 12-24 HOURS OUT CONFIDENCE REMAINS RELATIVELY LOW DUE TO
UNCERTAINTIES WITH REGARD TO THE EVOLUTION OF THE MESOSCALE
PATTERN...DEPENDING ON HOW STORMS EVOLVE OVER THE EASTERN DAKOTAS
INTO NORTHWEST MINNESOTA WILL DRIVE THE PRECIP COVERAGE/INTENSITY
THIS EVENING AND OVERNIGHT. IN GENERAL DO EXPECT SHOWERS WITH
ISOLATED/SCATTERED THUNDERSTORMS ACROSS NORTHEAST MINNESOTA LATE
TONIGHT. MUCAPE VALUES OF 100-300 J/KG ARE POSSIBLE MAINLY FROM THE
IRON RANGE SOUTH TO THE BRAINERD LAKES REGION...SUSTAINED BY A
STRONG 30-40KT LLJ. BRIEF HEAVY RAIN WILL BE THE MAIN CONCERN WITH
THESE STORMS...THOUGH A FEW GUSTS TO 30-40 KTS ARE ALSO POSSIBLE
ESPECIALLY IF COLD POOLS MERGE AND ORGANIZE. LEANING TOWARDS A
SHOWERS/ISOLATED STORMS SCENARIO...BUT THERE IS THE LOW POTENTIAL
FOR STRONG STORMS OVERNIGHT ESPECIALLY FROM HIBBING SOUTH TO THE
BRAINERD LAKES REGION. OTHERWISE OVERNIGHT WILL BE CLOUDY WITH TEMPS
IN THE LOW 40S BY THE LAKE...MID 50S TO NEAR 60 INLAND.

ON WEDNESDAY ANOTHER ROUND OF SHOWERS AND STORMS ARE
EXPECTED...MAINLY ACROSS AREAS SOUTH OF HIGHWAY 2 AND ESPECIALLY
INTO NORTHWEST WISCONSIN. ALSO EXPECT SOME ISOLATED SHOWERS/STORMS
IN NORTHEAST MINNESOTA BEHIND THE FRONT DUE TO POST-FRONTAL
INSTABILITY. MAIN CONCERN FROM STORMS TOMORROW WILL BE HEAVY RAIN AS
PRECIPITABLE WATER VALUES APPROACH 1.5 INCHES...WHICH WELL OVER THE
90TH PERCENTILE CLIMATOLOGY AND NEAR RECORD VALUES PER INL CLIMO.
TOTAL RAINFALL AMOUNTS OF A TENTH OF AN INCH ARE EXPECTED BUT
LOCALLY HIGHER AMOUNTS OF NEAR A HALF INCH ARE POSSIBLE IN AREAS
WHERE STORMS TRAIN DUE TO THESE CONDITIONS IN PLACE. MOSTLY CLOUDY
SKIES WILL LIMIT DIURNAL HEATING...BUT EVEN WITH THE LACK OF DIRECT
SUN EXPECT HIGHS TO WARM UP TO THE UPPER 60S TO NEAR 70.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE JUN 2 2015

THE LONG TERM WILL START OUT WET WITH A COLD FRONT POISED TO MOVE
THROUGH THE NORTHLAND WEDNESDAY NIGHT AHEAD OF A LOW PRESSURE
SYSTEM. THE NAM/ECMWF/GFS DIVERGE ON THE PLACEMENT OF THE LOW AND
THE QPF FORECAST THE MOST... OTHERWISE CONFIDENCE OF POPS IS
GOOD/SATISFACTORY. SREF MODEL SHOWS MARGINAL MUCAPE ACROSS THE CWA
THROUGH 06Z BEFORE TRAILING INSTABILITY OFF FROM WEST AND NORTH...
THEREFORE DECIDED TO ADJUST AND MOSTLY KEEP THUNDERSTORMS TIED TO
THE SOUTH... WITH POPS DECREASING TO SLIGHT CHANCES BY THURSDAY
AFTERNOON AND FRIDAY. A HIGH PRESSURE RIDGE OVER SOUTHERN ONTARIO
BUILD ACROSS SOUTHERN ONTARIO AND NORTHERN LAKE SUPERIOR ON
FRIDAY... WHICH WILL KEEP RAIN AT BAY UNTIL SATURDAY WHEN A NEW TROF
OF LOW PRESSURE WILL APPROACH FROM THE WEST. INSTABILITY WILL AGAIN
BE HIGH ENOUGH TO KEEP THE POTENTIAL FOR THUNDERSTORMS SATURDAY
AFTERNOON AND INTO SUNDAY... THOUGH THE THREAT FOR SEVERE WEATHER
REMAINS LOW AT THIS TIME. THE BEGINNING OF NEXT WEEK SHOWS SOME
INDICATIONS OF LIGHT PRECIP AND CHANCES OF THUNDERSTORMS.

TEMPS WILL REMAIN ON THE WARMER SIDE... WITH HIGHS GENERALLY IN THE
UPPER 60S TO LOW 70S... LOWS IN THE UPPER 40S TO MID 50S... AND
COOLER BY THE LAKE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 714 PM CDT TUE JUN 2 2015

VERY SLOW MOVING FRONTAL BOUNDARY WILL SAG SOUTHEASTWARD ACROSS
THE AREA OVER THE NEXT 24-36 HOURS..WITH SEVERAL PERIODS OF
SHOWERS/TSTORMS AND FLIGHT CATEGORIES FALLING INTO MVFR AND
PERHAPS SOME IFR AFTER ROUGHLY 9 HOURS INTO THIS TAF CYCLE.
INITIAL ROUND OF SHOWERS/WEAK TSTORMS WILL AFFECT KINL THROUGH THE
EVENING AND OVERNIGHT..WITH GREATER CHANCES FOR SHOWERS/TSTORMS
AFFECTING ALL OTHER TAF SITES BETWEEN 09-12Z TUE MORNING.
EXPECTING A SHORT MINIMUM IN COVERAGE/INTENSITY OF TSTORMS
MIDDAY/EARLY AFTERNOON TUE BEFORE MORE ACTIVITY DEVELOPS ALONG
FRONTAL BOUNDARY THAT SHOULD BE ROUGHLY ON AN AXIS FROM KBRD TO
THE NORTH SHORE OF LK SUPERIOR BY 20Z TUE.

MOST SIGNIFICANT CHANGES WITH THIS TAF ISSUANCE PACKAGE WERE TO
1) BACK OFF LOW CEILINGS TONIGHT AND TUE..AS WE EXPECT MOST OF THE
LOW MVFR/IFR CEILING POTENTIAL TO BE CONFINED TO AREAS ALONG AND
BEHIND THE FRONT.. 2) INTRODUCE MARGINAL LLWS CONDITIONS OVERNIGHT
TONIGHT AT ALL TAF SITES EXCEPT KINL WITH ~35KT 925 MB FLOW TO
DEVELOP AND 3) INTRODUCE A SHORT PERIOD OF FOG AND LOW CEILINGS AT
KDLH IMMEDIATELY FOLLOWING EXPECTED TSTORM ACTIVITY TUE MORNING.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  54  67  51  63 /  60  70  70  20
INL  57  69  48  75 /  80  40  50  10
BRD  61  71  58  72 /  60  50  20  20
HYR  57  71  56  71 /  50  70  60  20
ASX  52  72  50  61 /  40  60  60  40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&

$$







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