Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 201821
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1221 PM CST SAT DEC 20 2014

.UPDATE...
ISSUED AT 1216 PM CST SAT DEC 20 2014

HAVE ALLOWED THE WINTER WEATHER ADVISORY TO EXPIRE. ALTHOUGH THE
THREAT FOR ANY ICE ACCUMULATION HAS DIMINISHED...AREAS OF FOG AND
LIGHT SNOW SHOWERS/FLURRIES WILL BE COMMON ACROSS THE REGION THROUGH THE
AFTERNOON AND OVERNIGHT HOURS. CONTINUE TO ANTICIPATE UNTREATED
SIDEWALKS/ROADS TO BE SNOW COVERED AND SLIPPERY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CST SAT DEC 20 2014

LONG-DURATION LIGHT INTENSITY SNOW/FREEZING DRIZZLE CONTINUES
THROUGH THE WEEKEND DUE TO WARM ADVECTION AHEAD OF THE NEXT WEATHER
SYSTEM. TEMPERATURES WILL RISE GRADUALLY TO NEAR-FREEZING BY SUNDAY
AFTERNOON...WITH HIGHS AROUND 10 DEGREES ABOVE NORMAL AND LOWS
AROUND 25 DEGREES ABOVE NORMAL. FORECAST LOW TEMPS THIS WEEKEND WILL
RANK IN THE TOP TEN RECORD WARM LOWS AT DLH AND INL.

ON THE SYNOPTIC SCALE...SOMEWHAT OF A TRANSITIONAL PATTERN ALOFT
KEEPING THE NORTHLAND IN A PERSISTENT SOUTHWEST FLOW WITH TWO
SIGNIFICANT MID-LEVEL SHORTWAVE TROUGHS MOVING ACROSS...ONE THIS
MORNING THROUGH THE EARLY AFTERNOON AND THEN ANOTHER WAVE LATE
TONIGHT INTO TOMORROW. WARM AIR ADVECTION AT LOW/MID LEVELS WILL
CONTINUE THROUGH THE WEEKEND...WITH THE BEST PUSH OF WARMER AIR
ALOFT LATE SATURDAY NIGHT INTO SUNDAY AS THE SECOND MID-LEVEL
SHORTWAVE TROUGH DEPENDS AND MOVES EAST ACROSS THE INTERNATIONAL
BORDER REGION...WARM ENOUGH TO POSSIBLY CAUSE SLEET TO MIX IN IN A
FEW SPOTS IN CENTRAL MINNESOTA.

TODAY...OVERNIGHT THE WINTER WEATHER ADVISORY SEEMED TO BE WORKING
OUT WELL WITH LIGHT FREEZING DRIZZLE/FREEZING FOG CAUSING ICY ROAD
CONDITIONS ACCORDING TO A NUMBER OF AREA EMERGENCY DISPATCH CENTERS.
NO SURFACE STATION REPORTS OF FZDZ SPECIFICALLY...BUT THE AUTOMATED
WEATHER SENSORS TYPICALLY DO NOT DO WELL DIFFERENTIATING MIST/FOG
AND DRIZZLE. THESE CONDITIONS WILL CONTINUE THROUGH THE
AFTERNOON...WITH DRIZZLE TURNING MORE TO SNOW SHOWERS THIS AFTERNOON
AS THE MID-LEVEL MOISTURE INCREASES AND WE HAVE BETTER ICE CRYSTAL
GENERATION ALOFT. TEMPERATURES MILD...WARMING UP TO AROUND 30.

TONIGHT...EARLY IN THE EVENING SOME FREEZING DRIZZLE WILL BE
POSSIBLE AS WE EXPERIENCE DRYING AT MID-LEVELS AND WARMING AT CLOUD
TOP LEVEL...QUICKLY CHANGING TO ALL SNOW AFTER MIDNIGHT AS A STRONG
MID-LEVEL DISTURBANCE MOVES ACROSS THE REGION. THE BEST LARGE SCALE
FORCING WILL BE ACROSS KOOCHICHING/ITASCA/NORTHERN SAINT LOUIS
COUNTIES WHERE SOME SPOTS COULD SEE A QUICK INCH AFTER MIDNIGHT.
SOME SLEET MAY MIX IN AROUND THE BRAINERD LAKES REGION DUE TO A
NOSE OF WARM AIR ALOFT...BUT THE WINDOW OF OPPORTUNITY FOR THIS IS
FAIRLY LIMITED ON SPATIAL AND TEMPORAL SCALES. THE AREA OF SNOW
SHOWERS WILL GRADUALLY MOVE EAST TOWARDS MID-DAY SUNDAY. LOWS
HOLDING STEADY IN THE UPPER 20S.

SUNDAY...SNOW SHOWERS MOVING FROM WEST TO EAST WITH FLURRIES
POSSIBLE EVERYWHERE DUE TO THE LARGE-SCALE LIFT IN PLACE. WHILE
THERE WILL BE SOME CLEARING ALOFT IN THE FAR WESTERN PARTS OF THE
CWA...LOW LEVEL INVERSION MEANS THE STRATUS DECK WILL PERSIST. HIGHS
APPROACHING FREEZING.

TOTAL SNOWFALL THROUGH THE PERIOD WILL BE A COATING TO AN INCH IN
MOST SPOTS...WITH THE IRON RANGE AND POINTS NORTH POSSIBLY
RECEIVING JUST OVER AN INCH DUE TO A PERIOD OF HEAVIER SNOW SHOWERS
ON SUNDAY. NO SIGNIFICANT ICE ACCRETION IS EXPECTED THIS MORNING
WITH THE FREEZING DRIZZLE...BUT UNTREATED SURFACES COULD DEVELOP A
THIN LAYER OF ICE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 413 AM CST SAT DEC 20 2014

THIS PERIOD WILL BE DOMINATED BY A DIGGING TROF THAT WILL CLOSE OFF
IN THE UPPER MIDWEST. A 100+ KT UPPER LEVEL JET WILL HELP CREATE
AREAS OF WIDESPREAD UPWARD VERTICAL VELOCITY. THE SYSTEM WILL BECOME
VERTICALLY STACKED AND THE SUBSEQUENT SFC LOW WILL DEEPEN
CONSIDERABLY AS THE SYSTEM MEANDERS ACROSS THE MIDWEST THROUGH
WEDNESDAY.

THIS WEATHER SCHEME WILL BRING WIDESPREAD AND LONG LASTING LIGHT
SNOW TO AREAS OF THE NORTHLAND. AND THERE COULD BE SOME AREAS OF
HEAVIER BANDS OF SNOW BUT WHERE THESE WILL BE IS STILL UNCERTAIN.

BY SUNDAY NIGHT THE SFC LOW WILL BE OVER THE DAKOTAS WITH A STRONG
BAROCLINIC ZONE OVER CENTRAL MN AND WI...WHERE AN AREA OF STRONG
FGEN WILL DEVELOP...WITH NORTHLAND POSSIBLY IN THE AREA OF GREATEST
LIFT GENERATED BY THE FGEN PROCESS. THIS AREA REMAINS THROUGHOUT
MOST OF MONDAY...SO WE`LL SEE AN EXTENDED PERIOD OF LIGHT SNOW.
HOWEVER...AS MONDAY EVENING BEGINS WITH DRIER AIR ALOFT...THERE
COULD BE FREEZING DRIZZLE...BUT AS THE ATMOSPHERE SATURATES...THERE
WILL BE A QUICK CHANGEOVER OVER TO ALL SNOW MONDAY MORNING. SNOW
AMOUNTS DURING THE DAY COULD BE A FEW INCHES..AND WILL REFINE
AMOUNTS THROUGH THE WEEKEND.

THE SYSTEM WILL CONTINUE TO AFFECT THE NORTHLAND THROUGH
TUESDAY...THEN IT WILL PULL OUT OF THE AREA. SNOW AMOUNTS ARE HARD
TO PIN DOWN AS THE TRACK OF THE LOW SOLUTION IS NOT CLEAR...BUT
MUCH OF THE NORTHLAND COULD SEE MORE ACCUMULATING SNOW ON MONDAY
NIGHT AND TUESDAY.

THE  CYCLONIC FLOW AND COLD AIR ADVECTION BEHIND THE SYSTEM COULD
GENERATE SNOW SHOWERS ON WEDNESDAY.  A STIFF NORTHWEST WIND AND 8H
TEMPS FORECAST TO DIP TO -10C COLD GENERATE LAKE EFFECT SNOW SHOWERS
OVER NORTHWEST WI ON CHRISTMAS DAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1202 PM CST SAT DEC 20 2014

THERE WAS WIDESPREAD IFR AND LIFR CONDITIONS OVER NE MINNESOTA AND
NW WISCONSIN EARLY THIS AFTERNOON DUE TO OVC LIFR/IFR CIGS AND
IFR/MVFR VSBYS FROM BR/HZ AND -SN. THERE WERE LIGHT SOUTHERLY
WINDS.

THERE WILL LIKELY BE A LITTLE LIFTING THIS AFTERNOON TO MORE
WIDESPREAD IFR CIGS. THE KHYR AREA HAS LIFTED TO MVFR CIGS AND
THIS WILL LIKELY CONTINUE THROUGH AT LEAST THIS AFTERNOON. THERE
COULD BE LOWERING CIGS AGAIN THIS EVENING AND OVERNIGHT. BEST BET
IS FOR IFR CONDITIONS TO CONTINUE THROUGH TONIGHT AND SUNDAY
MORNING WITH LOWER VSBYS DUE TO HZ/BR AND OCCASIONAL -SN. THERE IS
A THREAT OF FREEZING DRIZZLE THROUGH SUNDAY MORNING...BUT THE
THREAT APPEARS TO BE VERY LOW BECAUSE OF THE ABSENCE OF A DEEP LOW
LEVEL SATURATED LAYER. IF ANYTHING...IT WOULD MORE LIKELY BE A
VERY LIGHT FREEZING MIST. THIS SHOULD NOT BE A SIGNIFICANT IMPACT.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  27  32  31  33 /  40  40  50  70
INL  27  32  29  32 /  60  60  20  40
BRD  27  34  31  34 /  30  30  50  70
HYR  27  34  33  36 /  30  40  60  70
ASX  27  35  33  37 /  20  40  60  60

&&

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

$$

UPDATE...GRANING
AVIATION...GROCHOCINSKI






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