Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 211622 AAB
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1022 AM CST SUN DEC 21 2014

.UPDATE...
ISSUED AT 1022 AM CST SUN DEC 21 2014

NO MAJOR CHANGES MADE TO THE FORECAST. LOWERED POPS ACROSS THE NRN
COUNTIES TOMORROW...BUT STILL EXPECTING A WINTRY MIX OVER MUCH OF
THE NORTHLAND AND LIGHT SNOW BEGINNING TO ACCUMULATE IN THE
ARROWHEAD TONIGHT. HOWEVER...THIS COULD BE MITIGATED BY SLIGHTLY
WARMER TEMPERATURES AND A MIX OF RAIN WITH THE SNOW.

UPDATE ISSUED AT 551 AM CST SUN DEC 21 2014

UPDATED AVIATION SECTION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 507 AM CST SUN DEC 21 2014

N ACTIVE WEATHER PATTERN THROUGH THE BEGINNING OF THE WORK WEEK
WILL RESULT IN ACCUMULATING SNOWFALL FOR THE ENTIRE REGION. IN THE
SHORT TERM THERE ARE TWO SEPARATE SYSTEMS OF NOTE...THE FIRST
PRIMARILY DRIVEN BY MID-LEVEL SHORTWAVE TROUGH/VORT MAX GRADUALLY
MOVING EAST ALONG THE CANADA/MINNESOTA BORDER EARLY THIS MORNING.
THIS FIRST SYSTEM WILL BRING LIGHT SNOWFALL TOTALS TO NORTHERN
MINNESOTA...MAINLY NORTH OF HIGHWAY 2. THE SECOND MORE DEVELOPED
SYSTEM WILL COME IN THE WAY OF A CLIPPER-TYPE SYSTEM WITH AN UPPER
LOW AND ACCOMPANYING SURFACE LOW THAT DEEPENS OVER THE NORTHERN
PLAINS BY MONDAY MORNING GRADUALLY MOVING EAST INTO SOUTHERN
MINNESOTA BY MONDAY NIGHT. THIS LOW WILL ALLOW FOR WARMER MOIST AIR
TO BE ADVECTED NORTHWARD WHICH COMBINED WITH THE LARGE SCALE FORCING
FROM THE UPPER LOW WILL RESULT IN A MIXED PRECIPITATION TYPE EVENT
THIS AFTERNOON THROUGH MONDAY.

THIS MORNING...OVERNIGHT RADAR...SATELLITE...AND SURFACE
OBSERVATIONS CONFIRMED AN AREA LIGHT SNOWFALL CONCENTRATED IN THE
ELY TO INTERNATIONAL FALLS REGION...WITH INL VISIBILITY REDUCING TO
BELOW A MILE AT TIMES DUE TO SNOWFALL. THIS REGION OF SNOWFALL WILL
MOVE EAST AND LIFT NORTH EARLY THIS MORNING WITH ANOTHER ROUND
ASSOCIATED WITH THE MAIN VORT MAX PVA EXPECTED LATER THIS MORNING
INTO THE EARLY AFTERNOON. ELSEWHERE PATCHY FOG AND PATCHY FREEZING
DRIZZLE EXPECTED DUE TO MID-LEVEL DRYING WHICH WILL MOVE EAST ACROSS
FAR NORTHERN MINNESOTA THIS MORNING...WITH THE DRY SLOT EVIDENT ON
SATELLITE WATER VAPOR IMAGERY THIS MORNING. TEMPERATURES STEADY OR
SLIGHTLY RISING NEAR 30.

TODAY...PATCHY FOG AND FREEZING DRIZZLE WITH LIGHT SNOW DEVELOPING
THROUGH THE AFTERNOON. THERE WILL BE A GOOD CHANCE FOR SNOWFALL ACROSS
THE TIP OF THE ARROWHEAD REGION /ESPECIALLY HIGHER TERRAIN/ WHERE
SOUTHERLY WINDS COULD RESULT IN SOME LAKE ENHANCEMENT. THE BEST AREA
FOR SNOWFALL WILL BE OVER NORTHWEST WISCONSIN AS STRONG WARM AIR
ADVECTION RESULTS IN EXCELLENT LARGE-SCALE LIFT. MODEL SOUNDINGS
INDICATE THE COLUMN WILL SATURATE EARLY THIS AFTERNOON OVER
NORTHWEST WISCONSIN WITH SNOWFALL SPREADING ACROSS THE REST OF THE
REGION BY THE EVENING HOURS. DAYTIME SNOWFALL TOTALS /ENDING AT 6PM
CST/ WILL BE ONE TO TWO INCHES IN NORTHWEST WISCONSIN AND ALONG THE
NORTH SHORE OF LAKE SUPERIOR. HIGHS WILL RISE TO THE LOW TO MID 30S.

TONIGHT...RISING TEMPERATURES AND STRONG WARM AIR ADVECTION WILL
RESULT IN A CHANGE FROM ALL SNOW TO A MIX OF RAIN AND SNOW. THERE IS
SOME CONCERN IF SNOWFALL RATES CAN BE INTENSE ENOUGH TO KEEP THINGS
ALL SNOW OVER NORTHWEST WISCONSIN...BUT AT THIS POINT WHILE THERE
WILL BE TIMES OF ALL SNOW FALLING THE MAJORITY OF THE OVERNIGHT
PERIOD WILL BE A MIX OF RAIN AND SNOW. SLEET WILL MIX IN FROM THE
BRAINERD LAKES REGION UP TO THE INTERNATIONAL FALLS REGION AND
POINTS WEST...BUT IT WILL BE MAINLY RAIN AND SNOW. TEMPERATURES WILL
RISE THROUGH THE NIGHT TO THE MID 30S BY MONDAY MORNING.

MONDAY...RAIN AND SNOW WILL CONTINUE THROUGH THE DAY. THERE MAY BE
PERIODS OF ALL RAIN OR ALL SNOW DURING THE AFTERNOON...BUT AT THIS
POINT WANTED TO KEEP THINGS AS A MIX. HIGHS IN MID TO UPPER 30S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 507 AM CST SUN DEC 21 2014

MONDAY NIGHT THROUGH TUESDAY NIGHT THE AREA WILL BE AFFECTED BY THIS
LONG DURATION LIGHT SNOW EVENT THAT WE HAVE BEEN WATCHING FOR A FEW
DAYS NOW.  THE STRONG...NEARLY CUT OFF UPPER LOW WILL MOVE SLOWLY
ACROSS THE MIDWEST...CAUSING A SURFACE LOW TO MOVE EAST FROM WESTERN
IOWA TUESDAY BEFORE SWOOPING NORTHEAST ACROSS WISCONSIN TO UPPER
MICHIGAN TUESDAY NIGHT.  THIS WILL PUT THE FORECAST AREA IN A VERY
NICE DEFORMATION ZONE OF PRECIPITATION FROM MONDAY NIGHT THROUGH
TUESDAY BEFORE WEAKENING TUESDAY NIGHT.  THE FORCING IS NOT VERY
STRONG...AND WARM TEMPERATURES WILL KEEP OUR SNOW WATER RATIOS LOWER
THAN USUAL FOR THIS TIME OF YEAR....SO AM NOT EXPECTING ANY LARGE
SNOWFALL AMOUNTS FOR ANY SINGLE PERIOD...GENERALLY 1 TO 3 INCHES.
HOWEVER...OROGRAPHICS AND LAKE EFFECT SNOW PROCESSES WILL ARE
EXPECTED TO BOOST SNOWFALL AMOUNTS FOR THE HIGHER TERRAIN OF THE
ARROWHEAD...WHERE WE COULD GET 2 TO 4 INCHES IN EACH PERIOD...WITH
EVENT TOTAL SNOWFALL AMOUNTS IN EXCESS OF 6 INCHES. WHILE TWO DAY
SNOWFALL AMOUNTS WILL BE FAIRLY IMPRESSIVE...AM EXPECTING THAT THE
LONG DURATION WILL KEEP US FROM MAKING WARNING CRITERIA.  THUS...FOR
NOW HAVE LEFT THE WATCH UP FOR THIS AREA...EXPECTING THAT UNLESS
THINGS CHANGE FOR THE DAY SHIFT TODAY...THE WATCH WILL BE CHANGED TO
AN ADVISORY FOR 12-18 HOURS OF LEAD TIME.

LIGHT SNOW WILL LINGER INTO WEDNESDAY AND POSSIBLY EVEN THURSDAY AS
THIS SYSTEM EXITS OFF TO THE EAST...WITH SOME POTENTIAL FOR LAKE
EFFECT SNOWS BOTH DAYS.  AS THIS SYSTEM EXITS OFF TO THE EAST WE
SHOULD GET SOME COLD TEMPERATURES FOR THE END OF THE WEEK AS SOME
CLEARING SKIES AND FRESH SNOW COVER ALLOW TEMPERATURES TO FALL OFF
OVERNIGHT.  LOW TEMPERATURES THURSDAY NIGHT MAY GET DOWN AROUND
ZERO.  FOR THURSDAY ON THOUGH...CONFIDENCE IN THE FORECAST IS LOWER
THAN NORMAL...WITH SOME MODELS HINTING AT ANOTHER FAST MOVING
SHORTWAVE BRINGING ACCUMULATING SNOWS TO PARTS OF THE AREA FOR
FRIDAY AND FRIDAY NIGHT.  WILL BE WATCHING THIS STORM CAREFULLY HAS
IT HAS SOME HIGH POTENTIAL TO HAVE IMPACTS ON HOLIDAY TRAVELERS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 551 AM CST SUN DEC 21 2014

ANOTHER 24 HOURS OF MAINLY IFR CEILINGS AND MVFR VISIBILITIES
EXPECTED. A SHORTWAVE MOVES ACROSS THE AREA BRINGING A SHORT
PERIOD OF IFR/LIFR -SN ALONG WITH SOME FZDZ AND FOG. AFTER A SHORT
BREAK AFTER 04Z WHEN CIGS REMAIN IFR BUT VSBYS MAY RETURN TO MVFR
IF NOT VFR. AFTER 07Z ANOTHER SYSTEM MOVES TOWARDS THE AREA AND
CIGS AND VSBYS LOWER ONCE AGAIN MAINLY FOR KBRD TO IFR.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  32  32  36  32 /  50  70  90  80
INL  32  31  36  31 /  40  40  70  70
BRD  33  32  35  30 /  10  70  80  70
HYR  34  34  36  33 /  70  70  90  70
ASX  35  34  38  33 /  50  60  80  70

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
     FOR MNZ012-020-021.

WI...NONE.
LS...NONE.
&&

$$

UPDATE...BJT
SHORT TERM...JJM
LONG TERM...LE
AVIATION...LE






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