Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 241745 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1245 PM CDT TUE MAR 24 2015

.UPDATE...
ISSUED AT 1245 PM CDT TUE MAR 24 2015

UPDATED FOR THE 18Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 408 AM CDT TUE MAR 24 2015

PRIMARY CONCERN IN THE SHORT TERM IS THE INCOMING COMPLEX SPRING
STORM SYSTEM WHICH WILL IMPACT THE REGION THROUGH THE MID-WEEK. AS
CAN BE EXPECTED WITH A COMPLEX SET UP THERE HAS BEEN A LOT OF
UNCERTAINTY LEADING UP TO THIS EVENT...BUT CONFIDENCE IS INCREASING
THAT THIS WILL BE A MOSTLY SNOW EVENT WITH LIGHT AMOUNTS THROUGH
MUCH OF NORTHEAST MINNESOTA WITH HIGHER TOTALS IN NORTHWEST
WISCONSIN. OTHER CONCERNS FOR THE SHORT TERM INCLUDE WINDS...BREEZY
OUT OF THE SOUTH TODAY AND BECOMING WINDY IN PARTS OF NORTH-CENTRAL
MINNESOTA TOMORROW AS SFC LOW DEPARTS. TEMPERATURES GENERALLY MILD
TODAY DUE TO WARM AIR ADVECTION AT LOW/MID LEVELS...BECOMING CLOSE
TO NORMAL TOMORROW.

ON THE SYNOPTIC SCALE A MID-LEVEL SHORTWAVE RIDGE WILL BE OVER THE
UPPER MIDWEST ON TUESDAY MORNING WITH A SHORTWAVE TROUGH DEVELOPING
ACROSS THE HIGH PLAINS. THIS TROUGH DEEPENS AS IT MOVES EASTWARDS
INTO THE PLAINS...QUICKLY BECOMING NEGATIVELY TILTED. BY 00Z WED THE
TROUGH AXIS WILL EXTEND FROM THE DAKOTAS SOUTHEAST TO THE MID
MISSISSIPPI VALLEY. WHILE AT MID/UPPER LEVELS THIS SYSTEM WILL BE
FAIRLY WELL CONNECTED...THE SURFACE FEATURES WILL BE MUCH MORE
COMPLEX. ON TUESDAY THE PRIMARY SFC LOW WILL DEVELOP ACROSS NORTH
DAKOTA. MEANWHILE A WEAKER SFC LOW OVER THE OKLAHOMA PANHANDLE WILL
TREK NORTHEASTWARD QUICKLY...BECOMING CENTERED OVER ILLINOIS BY WED
06Z. THIS TRACK OF THE SOUTHERN LOW HAS TRENDED FASTER AND FURTHER
SOUTH OVER THE PREVIOUS FEW DAYS OF MODEL RUNS...CUTTING OFF MUCH OF
THE REGION FROM A MUCH MORE MOIST AIR MASS.

TODAY...MILD WITH A MIX OF SUN AND CLOUDS DUE TO WARM AIR ADVECTION
AT LOW LEVELS THROUGH THE AFTERNOON. MORNING STRATUS ACROSS MUCH OF
NORTH-CENTRAL MINNESOTA WILL DISSIPATE TOWARDS LATE MORNING...ONLY
TO BE REPLACED BY CIRRUS CLOUDS THIS AFTERNOON. SOUTHERLY WINDS AT
10 TO 15 MPH WITH FEW GUSTS TO 25 MPH POSSIBLE. HIGHS IN THE LOW TO
MID 40S...AND MAYBE EVEN WARMER ACROSS THE BORDERLAND AND MUCH OF
NORTHWEST WISCONSIN. THE MAIN EXCEPTION WILL BE ALONG THE NORTH
SHORE INTO THE TIP OF THE ARROWHEAD WHERE HIGHS WILL BE LIMITS TO
THE MID TO UPPER 30S DUE TO A LAKE BREEZE.

TONIGHT...OVERCAST WITH LIGHT SNOW BEGINNING TOWARDS MIDNIGHT. PRECIP
MAY BEGIN AS A LIGHT MIX OF RAIN/SNOW ESPECIALLY IN NORTH CENTRAL
MINNESOTA WEST OF HIGHWAY 53...BUT WILL QUICKLY CHANGE OVER TO ALL
SNOW. THE MOST INTENSE PRECIP WILL FALL FROM MIDNIGHT TO SUNRISE
WEDNESDAY MORNING FOCUSED SOUTH OF HIGHWAY 2. SNOWFALL AMOUNTS BY
WEDNESDAY MORNING WILL BE GENERALLY LIGHT...GENERALLY ONE TO THREE
INCHES SOUTH OF HIGHWAY 2...WHICH IS MUCH LESS THAN PREVIOUSLY
FORECAST DUE TO A SHIFT IN THE SOUTHERN SYSTEM LOW PRESSURE TRACK.
FARTHER NORTH /EG NORTH OF HIGHWAY 2 IN NORTHEAST MINNESOTA/ LIGHT
SNOWFALL WILL ALSO BE FALLING LATE TONIGHT INTO WEDNESDAY
MORNING...WITH AMOUNTS OF ONE TO TWO INCHES. LOWS IN THE UPPER 20S
IN NORTHWEST WISCONSIN AND MN ARROWHEAD TO LOW 30S ELSEWHERE.

WEDNESDAY...TRANSITIONAL PATTERN THROUGH THE DAY AS SNOWFALL ENDS
SOUTH OF HIGHWAY 2 WHILE ANOTHER WAVE OF PRECIP MOVES ACROSS
NORTHEAST MINNESOTA...MOSTLY SNOW WITH RAIN MIXING IN AT TIMES.
BETWEEN THESE TWO WAVES THERE WILL BE A CHANCE FOR FLURRIES OR
FREEZING DRIZZLE DUE TO MID-LEVEL DRYING...BUT DUE TO THE
COMPLEXITIES ALREADY IN THE FORECAST KEPT THE WEATHER FORECAST
SIMPLE WITH JUST RAIN/SNOW. WITH PRECIP CHANGING OVER TO RAIN AT
TIMES IN THE AFTERNOON TOTAL SNOWFALL AMOUNTS WILL BE
LIMITED...PERHAPS AN ADDITIONAL INCH OR TWO ACROSS NORTHEAST
MINNESOTA. NORTHERN SFC LOW WILL MOVE EAST ACROSS THE INTERNATIONAL
BORDER DURING THE DAY...BECOMING CENTERED NEAR THUNDER BAY BY 00Z
THURSDAY. AS THE LOW DEPARTS A COLD FRONT WILL MOVE IN FROM THE
NORTH...AND BREEZY WESTERLY WINDS WILL DEVELOP IN CENTRAL MINNESOTA.
COULD SEE THE POTENTIAL FOR GUSTS UP TO 30 MPH ALONG AND SOUTH OF
HIGHWAY 2 IN MINNESOTA...WHICH IN COMBINATION WITH SNOWFALL COULD
RESULT IN BLOWING SNOW IN OPEN AREAS...BUT THIS SHOULD NOT BE A
MAJOR ISSUE WITH THE WET NATURE OF THE SNOW AND WARM SURFACE TEMPS.
HIGHS LOW 30S IN THE MN ARROWHEAD TO MID/UPPER 30S ELSEWHERE.

THE TWIN PORTS WILL BE BETWEEN THESE TWO STORM SYSTEMS...LIKELY
RECEIVING PRECIPITATION FROM BOTH. TOTAL SNOWFALL AMOUNTS FOR
TONIGHT INTO WEDNESDAY WILL BE ONE TO TWO INCHES FOR THE TWIN
PORTS...BUT AS STATED ABOVE A CHANGEOVER TO RAIN WILL LIMIT SNOWFALL
TOTALS. TRAVEL IMPACTS FROM THIS STORM WILL BE RELATIVELY
MINOR...WITH A SLICK WEDNESDAY MORNING COMMUTE BEING THE MAIN
CONCERN.

WITH TOTAL SNOWFALL AMOUNTS ACROSS THE NORTHLAND GENERALLY ONE TO
THREE INCHES FOR TONIGHT THROUGH WEDNESDAY DO NOT ANTICIPATE A
WINTER WEATHER ADVISORY BEING NEEDED AT THIS TIMES. AS STATED ABOVE
THIS IS A SHIFT FROM THE PREVIOUS FEW DAYS WHEN THE PATTERN WAS
LOOKING LIKE A MUCH STRONGER STORM...BUT AS THIS STRONGER STORM HAS
SHIFTED FARTHER SOUTH WE HAVE ADJUSTED THE FORECAST ACCORDINGLY.
CONFIDENCE FOR THIS SYSTEM ON THE WHOLE IS ABOUT AVERAGE...BUT STILL
HAVE CONCERNS ABOUT MINOR DETAILS SUCH AS PRECIPITATION TYPE DURING
THE DAY WEDNESDAY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 408 AM CDT TUE MAR 24 2015

UPPER LEVEL LONG WAVE TROF WILL BE OVER THE FORECAST AREA WEDNESDAY
NIGHT WHILE A SFC TROF LINGERS NEARBY. AN H85 COLD FRONT MOVES
THROUGH WITH TEMPS DROPPING INTO THE -14 TO -16C RANGE. THESE
FEATURES WILL PRODUCE ADDITIONAL LIGHT SNOW...ENDING FROM THE WEST
LATE. LAKE EFFECT SNOW SHOWERS WILL GET GOING LATE WITH STRONG
NORTHERLY FLOW OVER LAKE SUPERIOR...CAA AND LONG FETCH. WILL SEE
ADDITIONAL ACCUMULATION OVER NW WI AS A RESULT. THE CAA CONTINUES
THURSDAY...BUT THE MODELS ARE STARTING TO SHOW SOME DIFFERENCES IN
THE HANDLING OF ANY LAKE EFFECT POTENTIAL AND THE AMOUNT OF DRY AIR
INVOLVED FROM BUILDING HIGH PRESSURE. LEANED MORE TOWARDS THE GFS
WHICH HAS BEEN THE MOST CONSISTENT AND HAVE POPS/QPF/LAKE EFFECT
SNOW SHOWERS. ADDITIONAL LIGHT ACCUMULATION IS POSSIBLE. SOME LIGHT
LAKE EFFECT IS STILL POSSIBLE THURSDAY NIGHT PER THE GFS WHICH KEEPS
THE NORTHERLY FLOW GOING. HIGH PRESSURE BUILDS OVER THE REST OF THE
AREA. THE HIGH DRIFTS OVERHEAD FRIDAY ENDING THE LAKE EFFECT. THE
HIGH LINGERS THROUGH FRIDAY NIGHT. MODELS DIFFER ON SATURDAY WITH
THE TIMING OF PRECIPITATION. THE GFS IS FASTEST AND FURTHEST SOUTH
INTO THE NW CORNER OF THE FORECAST AREA. OTHER MODELS ARE DRY. HAVE
DIALED BACK THE POPS TO THE FAR NW CORNER OF KOOCHICHING COUNTY AND
NO MENTION OF RAIN UNTIL THE AFTERNOON. SATURDAY NIGHT THE
DIFFERENCES CONTINUE WITH THE GFS GENERATING COPIOUS AMOUNTS OF QPF
THROUGH THE ENTIRE AREA WHILE THE ECMWF JUST HAS PRECIP OVER THE
EASTERN EDGE OF THE FORECAST AREA. USED A BLENDED APPROACH...WHICH
WAS USED ON SUNDAY AS WELL AS MODELS DIVERGE FURTHER. THE GFS
APPEARS TO BE SUFFERING FROM GRID SCALE FEEDBACK THROUGH EACH OF
THESE PERIODS. MAINTAINED THE BLEND SUNDAY NIGHT WHICH RESULTS IN
SOME ISOLD POPS. HIGH PRESSURE FINALLY TAKES OVER FOR MONDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1245 PM CDT TUE MAR 24 2015

MUCH OF NE MINNESOTA AND NW WISCONSIN HAD VFR CONDITIONS WITH SCT
HIGH CLOUDS AND BREEZY SSE WINDS EARLY THIS AFTERNOON.

THE VFR CONDITIONS SHOULD CONTINUE THROUGH EARLY THIS EVENING. A
LOW PRESSURE IN CENTRAL NORTH DAKOTA WILL MOVE INTO EASTERN NORTH
DAKOTA THIS EVENING AND THEN NW MINNESOTA EARLY WEDNESDAY. THIS
APPROACHING LOW WILL BRING -SN AND WIDESPREAD IFR/MVFR CIGS AND
VSBYS TO THE REGION. THE IFR/MVFR CIGS WILL GENERALLY SPREAD FROM
SW TO NE...REACHING KBRD BEFORE MIDNIGHT...AND OTHER TERMINALS
AROUND MIDNIGHT OR THE WEE HOURS OF WEDNESDAY MORNING. THERE COULD
BE BRIEF LIFR CONDITIONS DUE TO CIGS...BUT CONFIDENCE OF THIS IS
LOW.

THE IFR/MVFR CONDITIONS COULD LINGER WELL INTO WEDNESDAY MORNING.
HOWEVER...THERE SHOULD BE A TRANSITION TO MORE PREDOMINANT MVFR
CONDITIONS DURING THE LATE MORNING AS WESTERLY WINDS BEGIN TO
DEVELOP IN THE WAKE OF THE LOW...WHICH WILL BEGIN MOVING INTO NW
ONTARIO AND LAKE SUPERIOR BY WEDNESDAY AFTERNOON. THE -SN MAY
BEGIN TO BE MIXED WITH RAIN AS THE TEMPERATURES WARM UP BY
WEDNESDAY AFTERNOON.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  45  29  38  24 /   0  80  70  40
INL  47  32  37  17 /   0  80  80  40
BRD  43  31  38  24 /  20  90  60  20
HYR  46  28  40  26 /  10  90  70  30
ASX  49  30  40  25 /   0 100  70  50

&&

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

$$

SHORT TERM...JJM
LONG TERM...GSF
AVIATION...GROCHOCINSKI






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