Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 181204
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
704 AM CDT SAT APR 18 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 333 AM CDT SAT APR 18 2015

THE FOCUS REMAINS ON THE APPROACHING LOW PRESSURE SYSTEM THAT WILL
BRING CONSIDERABLE RAINFALL TO THE NORTHLAND TONIGHT AND SUNDAY.
THE GENERAL TIMING OF THE ONSET OF THE RAIN IN THE 00Z
WRF/NAM/GFS/GEM/ECMWF MODELS WAS GENERALLY SLOWER THAN THE
PREVIOUS FORECAST...SO DELAYED THE TIMING OF WHEN THE RAIN MOVES
INTO THE FORECAST AREA. INCREASED THE PCPN CHANCES AND RAINFALL IN
THIS LATEST FORECAST.

AT 330 AM...AN AREA OF SURFACE HIGH PRESSURE WAS OVER NW ONTARIO.
THE NORTHLAND HAD CLEAR SKIES AND LIGHT NE WIND. TEMPERATURES
RANGED FROM THE UPPER 20S AND LOWER 30S OVER THE NORTHERN FORECAST
AREA TO THE UPPER 40S TO LOWER 50S OVER THE SOUTH.

TODAY...THE AREA OF SURFACE HIGH PRESSURE OVER NW ONTARIO THIS
MORNING WILL GRADUALLY SHIFT EAST...REACHING THE QUEBEC BORDER BY
THIS EVENING. THE DAY WILL BEGIN SUNNY...BUT THERE WILL BE
INCREASING CLOUD COVER FROM THE SOUTH DURING THE AFTERNOON AS LOW
PRESSURE ADVANCES INTO THE PLAINS. EASTERLY AND SOUTHEASTERLY
WINDS WILL KEEP THE ARROWHEAD...TWIN PORTS...AND AREAS OF NW
WISCONSIN NEAR LAKE SUPERIOR SIGNIFICANTLY COOLER THAN AREAS
FARTHER INLAND. HIGH TEMPERATURES WILL RANGE FROM THE UPPER 40S
AND LOWER 50S NEAR LAKE SUPERIOR TO THE 60S WELL INLAND. THE WINDS
WILL BECOME GUSTY NEAR THE TWIN PORTS DUE TO THE STRONG ENE FLOW
OFF OF THE LAKE...AND GUSTS UP TO AROUND 25 MPH ARE FORECAST.
THERE WILL BE LOW HUMIDITY AGAIN TODAY...ESPECIALLY FOR AREAS WELL
INLAND FROM LAKE SUPERIOR WHICH WILL SEE THE RELATIVE HUMIDITY
DROP TO 20 TO 30 PERCENT THIS AFTERNOON. THANKFULLY...THE WINDS
SHOULD NOT BE PARTICULARLY STRONG IN THE DRIEST AREAS. MOST OF THE
FORECAST AREA...OUTSIDE OF THE TWIN PORTS AREA...CAN EXPECT
SUSTAINED WINDS AROUND 10 MPH AND GUSTS OF 15 TO 20 MPH.
NONETHELESS...SOME AREAS COULD BRIEFLY APPROACH CRITICAL FIRE
WEATHER CONDITIONS.

TONIGHT AND SUNDAY...A SURFACE LOW WILL BE OVER EASTERN SOUTH
DAKOTA BY THIS EVENING. THERE WILL ALSO BE AN UPPER LEVEL LOW AND
ITS ASSOCIATED SURFACE REFLECTION OVER SASKATCHEWAN/MANITOBA THIS
EVENING. THE CANADIAN LOW WILL DEEPEN AS IT DIGS SE TOWARDS NW
ONTARIO THROUGH SUNDAY. THE SOUTH DAKOTA LOW WILL MOVE EAST
THROUGH SOUTHERN/CENTRAL MINNESOTA TONIGHT AND THROUGH THE
SOUTHERN FORECAST AREA SUNDAY. THE TWO LOWS WILL GRADUALLY BEGIN
TO CONVERGE TOGETHER SUNDAY. THESE LOW PRESSURE SYSTEMS ARE GOING
TO BRING A SURGE OF MOISTURE INTO THE NORTHLAND TONIGHT AND SUNDAY
AND CONSIDERABLE RAINFALL TO THE NORTHLAND. THE PRECIPITABLE WATER
VALUES WILL INCREASE TO 0.75 TO 1.0 INCH...WHICH IS
CLIMATOLOGICALLY VERY HIGH FOR THE MIDDLE OF APRIL. WIDESPREAD
RAINFALL AMOUNTS OF ONE HALF TO ONE INCH IS FORECAST FOR THE
NORTHLAND. SOME AREAS OF THE WESTERN AND NORTHERN FORECAST AREA
COULD GET UP TO AROUND 1.5 INCHES. THIS RAINFALL WILL BE WELCOME
RELIEF TO THE MODERATE DROUGHT CONDITIONS ACROSS THE NORTHLAND.
THE TEMPERATURES WILL BE CONSIDERABLY COOLER SUNDAY DUE TO THE
CLOUD COVER AND RAIN. HIGHS WILL BE IN THE UPPER 40S TO MIDDLE
50S.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 333 AM CDT SAT APR 18 2015

AN ELONGATED AREA OF LOW PRESSURE WILL CONTINUE TO MOVE EASTWARD
ACROSS THE NORTHLAND SUNDAY NIGHT...AS A STRONG H5 UPPER LOW DROPS
INTO THE GREAT LAKES REGION MONDAY AFTERNOON. PRECIPITATION WILL
START OUT IN THE FORM OF RAIN SUNDAY NIGHT...BUT TRANSITION TO SNOW
OR A RAIN/SNOW MIX LATER SUNDAY NIGHT AND ON MONDAY. BY MONDAY
NIGHT...MUCH OF THE PRECIPITATION WILL BE IN THE FORM OF SNOW. MODEL
RUN SNOW ACCUMULATION IS HIGHEST ON THE GEM...BUT THE OTHER MODELS
SHOW THE POTENTIAL FOR MAYBE A 2 TO 4 INCH SNOWFALL. THE BEST CHANCE
WOULD BE ALONG AND NORTH OF THE HIGHWAY 2 CORRIDOR...AND ESPECIALLY
ACROSS NORTH CENTRAL MINNESOTA AND THE ARROWHEAD. SREF PLUME MEAN
VALUES ALSO SUPPORT THIS...WITH MUCH LESS TO THE SOUTH...AND THE
POTENTIAL FOR 2 TO 4 INCHES NORTH. SOME SNOW SHOWERS OR A DAYTIME
MIX WILL LINGER FOR A PERIOD OF TIME INTO MIDWEEK...ESPECIALLY
ACROSS THE ARROWHEAD AND THE SOUTH SHORE. HIGH PRESSURE WILL THEN
MOVE IN FOR THE REST OF THE EXTENDED TIME PERIOD WITH GENERALLY DRY
CONDITIONS FROM MID WEEK INTO THE FIRST PART OF THE WEEKEND. HIGH
TEMPERATURES THROUGHOUT THE EXTENDED TIME PERIOD WILL GENERALLY BE
IN THE 40S...BUT A FEW UPPER 30S WILL BE POSSIBLE AT TIMES. OVERALL
IT LOOKS LIKE A MUCH COOLER PERIOD THAN THE ONE WE HAVE JUST
EXPERIENCED.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 701 AM CDT SAT APR 18 2015

HIGH PRESSURE WILL BRING VFR CONDITIONS AND A GOOD DEAL OF
SUNSHINE TO THE AREA TODAY. SOME HIGH CLOUDS WILL STREAM IN AT
TIMES TODAY. CONDITIONS WILL CHANGE RATHER QUICKLY TONIGHT...AS
LOW PRESSURE LIFTS NORTHEAST INTO MINNESOTA BY 12Z SUNDAY. RAIN
WILL QUICKLY SPREAD NORTHWARD...AND IT WILL BECOME WIDESPREAD. VFR
CONDITIONS WILL GIVE WAY TO SOME MVFR CIGS/VSBYS AS THE NIGHT
WEARS ON.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  55  38  49  36 /   0  80  90  60
INL  63  38  51  33 /   0  70  90  60
BRD  66  45  56  35 /   0  90  90  40
HYR  66  42  56  37 /   0  80  90  70
ASX  55  40  55  38 /   0  70  80  80

&&

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

&&

$$

SHORT TERM...GROCHOCINSKI
LONG TERM...DAP
AVIATION...DAP





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