Area Forecast Discussion
Issued by NWS Duluth, MN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KDLH 160048 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
648 PM CST MON DEC 15 2014

.UPDATE...
ISSUED AT 648 PM CST MON DEC 15 2014

KDLH CORRELATION COEFFICIENT DATA CLEARLY SHOWS THE RAIN/SNOW
TRANSITION ZONE MOVING SLOWLY BUT STEADILY SOUTHEASTWARD..WITH THE
TRANSITION ZONE CENTERED FROM NEAR LAKE MILLE LACS TO THE WEST
SIDE OF OF DULUTH..TO THE NORTH SHORE AS OF 630 PM. WE DID
BRIEFLY CHANGE OVER TO ALL SNOW HERE AT THE OFFICE..LIKELY
ASSOCIATED WITH A SHORT PERIOD OF ENHANCED DIABATIC COOLING WITH A
SMALL AREA OF ENHANCED HIGHER REFLECTIVITIES AND PRECIP RATES..AND
THESE SMALL/TRANSIENT CHANGE AREAS WILL LIKELY PERSIST ALL EVENING
JUST TO THE EAST OF THE MAIN SYNOPTIC TRANSITION ZONE. PRECIP
SHOULD CHANGE TO ALL SNOW BETWEEN 6-8 PM ALONG MOST OF THE I-35
CORRIDOR AND THE NORTH SHORE..BUT WILL LIKELY TAKE SEVERAL MORE
HOURS ACROSS MUCH OF NW WISCONSIN WHERE THE LAYER OF WARM AIR
ALOFT IS STILL RATHER DEEP WITH SURFACE TEMPS IN THE UPPER 30S.

ROADS WILL LIKELY BECOME RATHER SLICK AND ICE COVERED WITHIN A
COUPLE HOURS AFTER THE CHANGE OVER..AS THE COMBINATION OF WET
ROADS..WET/COMPACTED SNOW AND TEMPS FALLING INTO THE UPPER 20S ALL
ACT TO RESULT IN A LAYER OF COMPACTED ICE.

IMPORTANT NOTE: KDLH DIFFERENTIAL REFLECTIVITY (ZDR) DATA APPEARS
TO BE OUT OF CALIBRATION. WE WILL NOT HAVE A CHANCE TO FIX THIS
UNTIL AFTER THE ONGOING PRECIP EVENT ENDS..SO USE KDLH ZDR DATA
WITH CAUTION UNTIL FURTHER NOTICE.

AVIATION DISCUSSION IS ALSO UPDATED BELOW FOR THE 00Z TAF ISSUANCE.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 335 PM CST MON DEC 15 2014

A CHALLENGING WINTRY PRECIPITATION EVENT ONGOING WITH DENSE FOG
FINALLY GETTING OUT OF HERE. WINTER WEATHER ADVISORIES IN EFFECT
MAINLY DUE TO CONCERN OF SLEET MIXING IN WITH SNOW. TEMPERATURES
FINALLY RETURN TO MORE SEASONABLE LEVELS THE COLD AIR MOVES IN FROM
THE NORTH.

LATE THIS AFTERNOON...SURFACE TEMPERATURES HAVE BEEN DROPPING A BIT
FASTER THAN ANTICIPATED AND AS OF 230 PM CST RAIN HAS ALREADY
CHANGING TO SNOW AT A FEW LOCATIONS INCLUDING ACROSS CASS AND ITASCA
COUNTIES. THIS FASTER TRANSITION TO COLDER TEMPS COULD LEAD TO AN
HOUR OR SO OF FREEZING/RAIN DRIZZLE BEFORE IT QUICKLY CHANGES TO
SNOW. PRECIPITABLE WATER VALUES ARE HIGH...0.75 INCHES WHICH IS ABOUT
3 STANDARD DEVIATIONS ABOVE NORMAL FOR THE REGION. IF RAIN CHANGES
TO SNOW ALONG THE INTERSTATE 35 CORRIDOR AND EAST INTO NORTHWEST
WISCONSIN FASTER THAN CURRENTLY FORECAST IT COULD LEAD TO HIGHER
THAN EXPECTED SNOWFALL AMOUNTS.

FOG LATE TODAY...WARM TEMPERATURES PLUS SNOW COVER HAS LEAD TO DENSE
FOG FOR MUCH OF THE AFTERNOON...WITH CLEARING FINALLY ACROSS MOST OF
NORTHERN MINNESOTA AS COLDER AND DRIER AIR HAS MADE ITS WAY FROM
NORTH TO SOUTH. DENSE FOG HAS PERSISTED ACROSS NORTHWEST WISCONSIN
DESPITE THE MODERATE RAINFALL AT TIMES...SO WILL CONTINUE WITH THE
DENSE FOG ADVISORY UNTIL 00Z.

WINTRY MIX  TO SNOW THIS EVENING...EXPECTING A QUICK TRANSITION
FROM  RAIN...TO SLEET...AND FINALLY SNOW LATE THIS AFTERNOON.
SNOWFALL WILL NOT TAKE LONG TO START TO ACCUMULATE DESPITE THE WET
AND ABOVE FREEZING TEMPERATURES AT THE SURFACE. BY 6 PM CST
PRECIPITATION WILL BE ALL LIGHT TO MODERATE SNOW ACROSS THE NORTH
SHORE AND SOUTH THROUGH THE INTERSTATE 35 CORRIDOR AND WEST TO
AROUND THE BRAINERD LAKES REGION. IN NORTHWEST WISCONSIN MODERATE
RAIN WILL TRANSITION QUICKLY TO SLEET AND FINALLY SNOW. IT MIGHT NOT
BE UNTIL MIDNIGHT THAT THE RAIN SNOW LINE REACHES PRICE COUNTY...BUT
BASED ON OBSERVATIONS SO FAR THIS AFTERNOON AM FAIRLY CONFIDENCE IT
WILL CHANGE OVER TO SNOW THERE BEFORE PRECIPITATION ENDS. NORTHERLY
WINDS ALONG LAKE SUPERIOR WILL LEAD TO SOME LAKE ENHANCEMENT ALONG
THE SOUTH SHORE...WHICH WILL LAST INTO THE EARLY PART OF THE WEEK.

TOTAL SNOWFALL AMOUNTS ARE ABOUT THE SAME AS THEY HAVE BEEN FOR THE
PAST FEW FORECAST WITH 2 TO 3 INCHES FROM THE TWIN PORTS UP THROUGH
THE ARROWHEAD REGION...1 TO 3 INCHES ACROSS INTERIOR NORTHWEST
WISCONSIN...AND 2 TO 4 INCHES ALONG THE SOUTH SHORE...WITH LOCALLY
HIGHER AMOUNTS IN THE HIGHER TERRAIN.

TEMPERATURES WILL DROP TO THE LOW TO MID TEENS IN NORTHERN
MINNESOTA...AND INTO THE LOW TO MID 20S IN NORTHWEST WISCONSIN.

TUESDAY...AS AN AREA OF HIGH PRESSURE MOVES INTO THE REGION SNOWFALL
WILL END EARLY IN THE MORNING IN NORTHERN MINNESOTA AND LINGER INTO
THE EARLY AFTERNOON ACROSS NORTHWEST WISCONSIN. LAKE EFFECT SNOWFALL
IN NORTHERN IRON/ASHLAND COUNTIES WILL CONTINUE THROUGH THE
DAY...AND ELSEWHERE SCATTERED FLURRIES ARE POSSIBLE. SKIES WILL
REMAIN MOSTLY CLOUDY THROUGHOUT THE DAY KEEPING TEMPERATURES IN THE
TEENS TO MID 20S.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 335 PM CST MON DEC 15 2014

TOMORROW NIGHT AND WEDNESDAY THE LINGERING UPPER LOW WOBBLES OVER
THE REGION...KEEPING LAKE EFFECT SNOW OVER NORTHERN WISCONSIN AND
LIGHTER SNOWS GOING OVER FAR NORTHERN MINNESOTA IN THE VICINITY OF
AN INVERTED TROUGH.  ADDITIONAL SNOWFALL AMOUNTS LOOK FAIRLY MINOR
AT THIS TIME...BUT CANNOT RULE OUT AN INCH OR TWO OVER THE LAKE
EFFECT REGIONS OF NORTHWEST WISCONSIN...AND LESS THAN AN INCH
ELSEWHERE.  CLOUDS TO KEEP TEMPERATURES MODERATED THROUGH
WEDNESDAY.  HOWEVER...WE SHOULD FINALLY LOSE SOME CLOUD COVER
WEDNESDAY NIGHT AND/OR THURSDAY...ALLOWING TEMPS TO FALL OFF INTO
THE SINGLE DIGITS OVER MUCH OF THE AREA WITH THE FRESH SNOW COVER
AND CLEARING SKIES. THERE IS SOME POTENTIAL FOR COLDER YET IF WE
ACTUALLY DO CLEAR...BUT GIVEN THE UNCERTAINTY HAVE JUST TRENDED THAT
DIRECTION.

LONG TERM FORECAST FROM THURSDAY THROUGH NEXT MONDAY IS PRETTY
QUIET...THOUGH SPLIT UPPER LEVEL FLOW DOES COMPLICATE THINGS.  WE
ARE MAINLY IN THE NORTHERN STREAM WITH SOME RIPPLES THAT COME
THROUGH DURING THE PERIOD.  A SHORTWAVE MOVES THROUGH FRIDAY NIGHT
AND SATURDAY...BUT WHILE I EXPECT US TO CLOUD UP AGAIN...BETTER LIFT
SHOULD BE NORTH AND SOUTH OF US...WITH LITTLE TO PRODUCE PRECIP FOR
THE CWA.   MODELS ARE HINTING AT A STRONGER SHORTWAVE TO MOVE ACROSS
THE AREA MONDAY...POSSIBLY PUTTING SOME SNOW DOWN ACROSS THE AREA
JUST A FEW DAYS BEFORE CHRISTMAS.  WE ARE GETTING OUT INTO A LOW
CONFIDENCE TIME FRAME THOUGH...AND AM ONLY CARRYING SOME SMALL POPS
AND WILL HAVE TO WATCH THIS FEATURE AS IT COULD HAVE SOME TRAVEL
IMPACTS IN THE DAYS LEADING UP TO THE HOLIDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 648 PM CST MON DEC 15 2014

PRECIP IS IN THE PROCESS OF TRANSITIONING TO ALL SNOW AT KDLH..
AND EXPECTED TRANSITION TIME IN KHYR IS 04-05Z. OTHERWISE
KBRD/KINL/KHIB WILL REMAIN ALL SNOW FOR THE DURATION OF THIS
EVENT. A SHORT PERIOD OF HALF MILE VISIBILITIES IN MODERATE SNOW
WITH LARGE AGGREGATE FLAKES IS EXPECTED IN KDLH/KHYR DURING THE
FIRST 6-9 HOURS OF THIS ISSUANCE. NORTH/NORTHWEST WINDS WILL
INCREASE TO 15G20-25KT DURING THE FIRST 6 HOURS..WITH PEAK OF
GUSTINESS EXPECTED ROUGHLY 06-12Z TIME FRAME..ESPECIALLY IN
KDLH/KHIB/KBRD. BREAK IN PRECIP AND DECREASE IN THE WINDS..ALONG
WITH IMPROVEMENT TO MVFR CONDITIONS EXPECTED TUE MORNING..BEFORE
MORE LIGHT SNOW REDEVELOPS LATE MORNING EARLY AFTERNOON WITH
CLOSED LOW DROPPING SOUTHWARD FROM NORTHWEST ONTARIO..MAINLY
AFFECTING KINL/KHIB/KDLH.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  19  20  11  20 /  90  10  10  10
INL  11  15   7  17 /  10  20  20  10
BRD  15  19  10  19 /  60  10  10  10
HYR  25  25  13  21 / 100  40  20  20
ASX  24  25  18  23 / 100  70  50  40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MNZ011-012-
     019>021-035>038.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ010-
     018-025-026-033-034.

WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ001-006.

LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 PM CST
     TUESDAY FOR LSZ121-146>148.

     SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM CST
     TUESDAY FOR LSZ140-141.

&&

$$

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.