National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDLH 080000
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
600 PM CST SAT DEC 7 2013

.SYNOPSIS...
ISSUED AT 315 PM CST SAT DEC 7 2013

RELATIVELY QUIET AND COLD WEATHER ACROSS THE NORTHLAND THIS
AFTERNOON...WITH THE STRONG SURFACE RIDGE POSITIONED OVER SOUTHERN
MINNESOTA AND LIGHT WEST WIND ACROSS THE FORECAST AREA.  LAKE EFFECT
SNOW SHOWERS ONGOING OVER THE LAKE...WHICH IS AFFECTING LAND AREAS
OVER THE U.P. OF MICHIGAN THIS AFTERNOON.  THERE IS ALSO A NICE
CONVERGENCE BAND ON RADAR IMAGERY OVER THE WESTERN TIP OF THE LAKE
WHERE SNOW SHOWERS ARE ONGOING.  TEMPERATURES REMAIN VERY COLD...AND
THE LIGHT WINDS HAVE BEEN CAUSING US TO FLIRT WITH WIND CHILL CRITERIA
ON AND OFF ALL AFTERNOON.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 315 PM CST SAT DEC 7 2013

TONIGHT THE SURFACE RIDGE TO SLIDE OFF TO THE EAST.  AN UPPER LEVEL
TROUGH OUT OVER THE ROCKIES WILL SHIFT EAST...AND A MID LEVEL WARM
AIR ADVECTION AND FRONTOGENESIS BAND WILL SPREAD EAST OUT OF THE
ROCKIES TONIGHT AND INTO MINNESOTA.  THIS IS GOING TO SPREAD HIGH
CLOUDS OVER THE FORECAST AREA OVERNIGHT...WITH GRADUALLY LOWERING
CEILINGS TOWARDS MORNING.  ACROSS THE FAR SOUTH WE MAY EVEN GET SOME
LIGHT SNOW WITH A LIGHT DUSTING OF ACCUMULATION POSSIBLE.  UNTIL
THEN THOUGH...IT WILL REMAIN VERY COLD WITH THE LIGHT WEST WIND
SLOWLY TURNING SOUTHWEST AND EVEN SOUTH OVERNIGHT.  WITH
TEMPERATURES FALLING ONCE AGAIN...EXPECT THAT THE WIND CHILL VALUES
WILL ONCE AGAIN FALL INTO ADVISORY CRITERIA.  THE NORTHERN HALF OF
THE AREA IS PRETTY CLEARLY IN ADVISORY CRITERIA. HOWEVER...THE
SOUTHERN PORTIONS OF THE AREA ARE MORE BORDERLINE WITH THE LIGHTER
WINDS AND SLIGHTLY WARMER TEMPS. IF THEY MAKE CRITERIA IT WILL BE
WITHIN ABOUT 3 HOURS EITHER SIDE OF MIDNIGHT...WITH RISING TEMPS
AFTER THAT.  HAVE GONE AHEAD AND ISSUED THE ADVISORY FOR THE WHOLE
AREA...BUT LATER SHIFTS MAY BE ABLE TO MAKE ADJUSTMENTS FOR TRENDS.

SUNDAY AND SUNDAY NIGHT THE UPPER LEVEL TROUGH AXIS MOVES ACROSS THE
MIDWEST...WITH A STRONG WARM AIR ADVECTION WING AND FRONTOGENESIS
ZONE MOVING ACROSS THE SOUTHERN HALF OF MINNESOTA AND WISCONSIN. THE
FORECAST AREA IS SITTING ON THE NORTHERN FRINGES OF THIS AREA...AND
EXPECT THAT THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA ARE
LOOKING AT A NICE 2 TO 4 INCH EVENT OVER ABOUT 12 HOURS...WITH 2
INCHES OR LESS OVER MOST OF THE REST OF THE FORECAST AREA.  SNOW
WATER RATIOS ARE LIKELY TO BE AROUND 20 TO 1...GIVEN THE COLD AIR
AND THE DEPTH OF THE -12 TO -18 LAYER. THE SOUTHEAST FLOW THAT SETS
UP AHEAD OF THIS SYSTEM FOR SUNDAY AFTERNOON AND EVENING IS LIKELY
TO ENHANCE SNOWFALL OVER THE NORTH SHORE OF LAKE SUPERIOR WITH LAKE
ENHANCEMENTS AND OROGRAPHIC EFFECTS.  THESE AREAS COULD SEE LOCALLY
HIGHER AMOUNTS IN THE 3 TO 5 INCH RANGE AS WELL.  HAVE DECIDED TO
ISSUE A WINTER WEATHER ADVISORY FOR 12Z SUNDAY TO 12Z MONDAY FOR
PORTIONS OF OUR NORTHWEST WISCONSIN COUNTIES...AND ANOTHER ADVISORY
FOR 18Z SUNDAY TO 12Z MONDAY FOR THE NORTHERN LAKE SHORE COUNTIES.
FOLLOWING SHIFTS WILL NEED TO EVALUATE THE NEED FOR ANY EXPANSION...
ESPECIALLY TO THE NORTHWEST WISCONSIN AREA.  TEMPERATURES REMAIN
COLD THROUGH THE PERIOD...BUT THE WARM AIR ADVECTION WILL PULL
TEMPERATURES UP INTO THE 5 ABOVE TO 15 ABOVE RANGE FOR
SUNDAY...BEFORE FALLING BACK TO AROUND ZERO OVERNIGHT SUNDAY NIGHT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 PM CST SAT DEC 7 2013

VERY COLD WEATHER PATTERN WILL PREVAIL THROUGHOUT THE WEEK AS
CIRCUMPOLAR VORTEX REMAINS DISPLACED WELL SOUTH ACROSS CONUS.
MIN/MAX TEMPS WILL REMAIN WELL BELOW CLIMO VALUES THROUGH WEDNESDAY
BEFORE MODIFICATION OF AIR MASS BEGINS SLOWLY. MULTI MDL AGREEMENT
THAT AN AMPLIFYING SHORTWAVE AT MID LVLS WILL DROP SOUTH ACROSS
REGION MONDAY NIGHT/TUESDAY WITH INCREASING CHC SNOW. THIS SYSTEM IS
FCST TO BE STRONG ENOUGH TO GENERATE A SFC REFLECTION DESPITE THE
ABUNDANCE OF ARCTIC AIR IN LOW LVLS. RAISED INHERITED POPS BUT
SUSPICION IS THAT WE MAY GO TO LIKELY AS WE APPROACH THE SYSTEMS
ARRIVAL. BEYOND THAT THE FLOW IS JUST TOO FAST TO DETAIL
TIMING/PLACEMENT OF ANY SIGNIFICANT FORCING. WILL KEEP FCST DRY TUES
EVENING INTO THURSDAY NIGHT AS  LARGE SFC HIGH DOMINATES THE REGION
UNDERNEATH BRISK NW MID LVL FLOW. NEXT OPPORTUNITY FOR PRECIP
ARRIVES THUR NIGHT/FRIDAY AS WEAK SFC WAVE TRACKS ACROSS NRN PLAINS
AND SOUTH OF CWA. ONLY SLIGHT CHC AT THIS TIME AND THAT MAY BE
REMOVED IN TIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 534 PM CST SAT DEC 7 2013

COLD AND VERY DRY AIR MASS WILL ALLOW VFR CONDITIONS TO PERSIST
ACROSS THE REGION THROUGH THE NIGHT. MAIN FOCUS DURING TAF PERIOD
WILL BE ADVANCING CLOUDS AND SNOW SHOWERS FROM THE SOUTH THROUGH
THE DAY SUNDAY. LATEST TREND IS TO CONTINUE TO SLOW DOWN ARRIVAL
TIME BY AN HOUR OR TWO. EXPECTING MVFR CIGS AND FLURRIES TO REACH
KBRD/KHYR DURING 14Z-16Z...FOLLOWED BY PREVAILING LIGHT SNOW AND
PERIODS OF IFR AFTER 18Z. THE LOW CLOUDS WILL REACH THE KHIB/KINL
AREAS LATER IN THE AFTERNOON...MAINLY AFTER 20Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH -16   8  -1   4 /  10  80  80  10
INL -25   6  -5  -2 /   0  50  60  20
BRD -19   8  -4  -1 /  30  60  60  10
HYR -20  11   2   4 /  30  90  90  10
ASX -12  12   7   8 /  20  90  90  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 11 AM CST SUNDAY FOR MNZ010>012-
     018>021-025-026-033>038.

     WINTER WEATHER ADVISORY FROM NOON SUNDAY TO 6 AM CST MONDAY FOR
     MNZ020-021.

WI...WIND CHILL ADVISORY UNTIL 11 AM CST SUNDAY FOR WIZ001>004-
     006>009.

     WINTER WEATHER ADVISORY FROM 6 AM SUNDAY TO 6 AM CST MONDAY FOR
     WIZ003-004-008-009.

LS...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR LSZ146>148.

&&

$$

SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...CANNON
AVIATION...GRANING