FXUS63 KDLH 120317
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
917 PM CST FRI DEC 11 2009

.UPDATE...FOR ZONE FCST
NO SIG CHG TO FCST. UPDATED ZFP FOR TIME REFERENCES.

&&

.PREV DISCUSSION... /ISSUED 524 PM CST FRI DEC 11 2009/ 

UPDATE...FOR 00Z TAFS

AVIATION...UPDATE FOR 00Z TAFS
VFR CONDS EXPECTED THRU TAF PD.

PREV DISCUSSION... /ISSUED 345 PM CST FRI DEC 11 2009/ 

DISCUSSION...
OVERNIGHT...A 40 KT LLJ WILL SHIFT EAST OVER THE NORTHLAND BRINGING 
MILD TEMPERATURES BACK TO THE FCST. A WEAK TROUGH WILL SETS UP ALONG 
THE INTERNATIONAL BORDER TONIGHT...LINGERING OVER THE NORTHLAND THROUGH
THE WEEKEND. THE TROUGH WILL BE THE FOCUS FOR CLOUDS AND AN ISOLD
-SHSN TONIGHT/SAT. KEPT SCHC POPS IN FAR NRN ZONES AND MENTION OF
FLURRIES ACROSS SOUTH AS MOISTURE AND GOOD FORCING WILL BE LACKING
FOR ACCUMULATION. THE EXCEPTION WILL BE ALONG THE NORTH SHORE IN
THE TIP OF THE MN ARROWHEAD...WHERE LAKE EFFECT/ENHANCED SNOW
SHOWERS WILL BE POSSIBLE...MAINLY FROM 03-09Z TONIGHT NE OF
LUTSEN. NAM12 CROSS SECTION NEAR KGNA SUGGESTS A SATURATED PROFILE
TO 800 MB WITH OMEGA OF >10 AND AN ONSHORE FETCH DURING THIS TIME.
INCREASED TO MID CHC IN THIS AREA WITH AROUND AN INCH OF
ACCUMULATION POSSIBLE. MID LVL RH NEEDED TO SUSTAIN ANY -SHSN
DROPS OFF RAPIDLY TO 40% BY 12Z SAT. 

FOCUS TURNS TO SUNDAY NIGHT AND MONDAY WHEN THE FIRST OF A SERIES
OF FAST MOVING WAVES BRINGS A THREAT FOR A FEW INCHES OF SNOW FOR
PORTIONS OF THE CWA. INCREASED TO BROAD HIGH CHANCE/LIKELY POPS
FOR THIS TIME FRAME. THERE REMAINS SIGNIFICANT MODEL DIFFERENCE IN
TIMING AND LOW PLACEMENT...BUT MUCH OF THE FA CAN EXPECT SOME
LIGHT ACCUMULATION FOR THE START OF THE WORK WEEK. ATTM...THE
GREATEST AMOUNTS /ON THE ORDER OF 2-4 INCHES/ LOOKS TO BE FOUND
ACROSS THE SRN HALF OF THE CWA FROM KXVG TO KDLH...AND ACROSS NRN
WIS.

EXTENDED...MONDAY NIGHT THRU FRIDAY.
A VIGOROUS UPPER LEVEL SHORTWAVE IS PROGGED TO TRACK ACROSS THE 
MIDWEST MONDAY NIGHT INTO TUESDAY. HOWEVER WITH STRONG CAA 
BEHIND THE DEPARTING SFC LOW...MOST OF THE PRECIP ASSOCIATED WITH 
THE SHORTWAVE SHOULD BE CONFINED TO OUR NRN ZONES...WITH LAKE EFFECT 
SNOW ACROSS THE SNOWBELT OF NWRN WISCONSIN. THE SNOW SHOWERS ACROSS 
OUR NRN ZONES SHOULD QUICKLY DIMINISH ON TUESDAY WITH THE DEPARTURE 
OF THE UPPER TROUGH. BUT THE LAKE EFFECT SNOW ALONG THE SOUTH SHORE 
WILL CONTINUE THROUGH AT LEAST TUESDAY NIGHT DUE TO FAVORABLE NWRLY 
WIND DIRECTION AND DELTA T VALUES RANGING FROM 13 TO 20 ACCORDING 
TO THE GFS. THE LAKE EFFECT SNOW SHOULD END ON WEDNESDAY AS THE 
RIDGE AXIS MOVES OVER THE WESTERN GREAT LAKES. BEYOND WEDNESDAY 
THERE IS MORE UNCERTAINTY IN THE FORECAST WITH A UPPER RIDGE 
BUILDING OVER THE MOUNTAIN WEST AND NORTHWEST FLOW SETTING UP OVER 
THE UPPER MIDWEST. THE GFS AND ECMWF INDICATE A SHORTWAVE DIGGING 
OVER THE REGION SOMETIME LATE NEXT WEEK OR EARLY NEXT WEEKEND...BUT 
DIFFER ON TIMING AND LOCATION OF PRECIP. THEREFORE WILL KEEP 
THURSDAY AND FRIDAY MOSTLY DRY ATTM.

PREV DISCUSSION... /ISSUED 1219 PM CST FRI DEC 11 2009/ 

AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD...EXCEPT FOR
LAKE EFFECT CLOUDS AND SNOW SHOWERS WITH MVFR/IFR CIGS/VSBYS OVER
LAKE SUPERIOR. A WEAK SHORTWAVE WILL TRACK EWD ACROSS THE
NORTHLAND TONIGHT. HOWEVER ONLY AREAS OF 4-8KFT CIGS ARE EXPECTED
WITH THE SYSTEM.

P

&&

.POINT TEMPS/POPS...
DLH   5  21  13  15 /  10  10  20  20 
INL  -3  13  -1   8 /  20  20  20  20 
BRD   3  21  10  18 /  10  10  10  20 
HYR  -3  23  13  23 /  10  10  20  20 
ASX   1  22  16  25 /  10  10  20  30 

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CST SATURDAY FOR LSZ140-141-146-
     147.

     SMALL CRAFT ADVISORY UNTIL 4 AM CST SATURDAY FOR LSZ121-144-145-
     148.

     SMALL CRAFT ADVISORY UNTIL 10 AM CST SATURDAY FOR LSZ142-143.

&&

$$

04/BERDES