weather.gov     
National Weather Service

Area Forecast Discussion
NWS Homepage
This page is being discontinued on March 12, 2014.
The same data is available at this site. Please update your bookmarks.
Thank you, and we apologize for the inconvenience.
Please send an email to SR-SRH.Webmaster@noaa.gov with any concerns.


Current Version
Previous Version:    01  02  03  04  05  06  07  08  09  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  
[Printable]
219
FXUS63 KDLH 231742
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1142 AM CST SUN NOV 23 2014

.UPDATE...
ISSUED AT 1140 AM CST SUN NOV 23 2014

UPDATED TO EXTEND THE DENSE FIG ADVISORY THORUGH 00Z TONIGHT AS
MANY OBS STILL SHOW LOW VISBILITIES ACROSS THE REGION.
ALSO...INCREASE POPS FOR RAIN IN PINE AND THE SOUTHERN NW WI
COUNTIES FOR THE AREA OF RAIN COMING UP FROM THE SOUTH.

***1140 AM CST AVIATION DISCUSSION AT BOTTOM***

UPDATE ISSUED AT 1001 AM CST SUN NOV 23 2014

UPDATED TO INCREASE MAX TEMPS IN NW WI AS THEY ARE ALREADY AT THE
PREVIOUSLY FORECASTED HIGHS. ALSO MADE MINOR CHANGES TO WINDS AND
POPS BASED ON CURRENT TRENDS. WILL KEEP DENSE FOG ADVISORY IN
EFFECT THROUGH 18Z SINCE THERE IS WIDESPREAD DENSE FOG IN THE REGION.

UPDATE ISSUED AT 534 AM CST SUN NOV 23 2014

UPDATED AVIATION DISCUSSION BELOW FOR 12Z TAF ISSUANCE.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 324 AM CST SUN NOV 23 2014

THERE REMAINS PLENTY OF CHALLENGES IN THE SHORT TERM...SPECIFICALLY
IN REGARDS TO SNOW AMOUNTS LATE TONIGHT INTO MONDAY.

THE 00Z MODEL SUITE FEATURED GFS/ECMWF SOLUTIONS THERE WERE IN
GENERAL AGREEMENT...THEN THE NAM/GEM WHICH WERE SLOWER WITH THE
LOW PRESSURE SYSTEM AND SUGGESTED HIGHER SNOWFALL OVER OUR FAR
EASTERN CWA INCLUDING NORTHWEST WISCONSIN. WE USED A BLEND AS WE
COULD NOT DISCOUNT THE SLOWER SOLUTIONS. A QUICK LOOK AT THE 06Z
NAM DOES SHOW THE LOW MOVING THROUGH A BIT FASTER.

A SOUTHERN STREAM WAVE MOVING THROUGH TEXAS AND NORTHERN STREAM WAVES
SEEN OVER THE NORTHERN PLAINS AND ANOTHER IN THE 4 CORNERS AREA WILL
ALL COMBINE TO CAUSE AN AREA OF LOW PRESSURE TO REFORM OVER/NEAR
SOUTHERN LAKE MICHIGAN THIS EVENING...THEN TRACKING THE LOW
NORTHEAST TONIGHT INTO MONDAY. THERE WILL BE A CHANCE FOR LIGHT
RAIN/DRIZZLE OVER MAINLY EASTERN AREAS TODAY...WITH THE BEST
CHANCE OVER OUR SOUTHEAST ZONES. CURRENT TEMPERATURES WERE IN THE
MID TO UPPER THIRTIES FOR MOST AREAS AS OF 09Z. THERE MAY BE SOME
SLICK SPOTS ON SOME ROADS THOUGH AS THOSE TEMPS MAY BE AT/BELOW
FREEZING.

COLDER TEMPERATURES WILL MOVE INTO WESTERN AREAS LATE TODAY...AND
SOUNDINGS/WET BULB TEMPERATURES SUGGEST PRECIP TYPE WILL
PROGRESSIVELY BECOME ALL SNOW FROM WEST TO EAST LATE TODAY INTO
TONIGHT. THE THREAT FOR FREEZING RAIN/DRIZZLE IS LOWER THAN PREVIOUSLY
EXPECTED. WE INCREASED CHANCES FOR SNOW LATE TONIGHT INTO MONDAY
FOR MOST AREAS AS MUCH COLDER AIR MOVES IN ON INCREASING NORTHWEST
WINDS. SNOW AMOUNTS ARE STILL IN QUESTION MONDAY...WITH THE
NAM/GEM SUGGESTING MUCH HIGHER AMOUNTS THAN WE HAD GOING. WE DID
INCREASE SNOWFALL...BUT DID NOT BUY INTO THE HIGH END AMOUNTS. THE
SREF PLUMES DEMONSTRATE THIS PROBLEM WITH THE 03Z RUN SHOWING
SNOWFALL SPREADS FROM NO ACCUM TO A COUPLE MEMBERS OVER 15INCHES
AT KDLH.

WE EXPECT WINDY CONDITIONS FOR MUCH OF THE NORTHLAND MONDAY...AND
HAVE SOME BLOWING SNOW MENTIONED. WE ARE NOT CONFIDENT ENOUGH TO
ISSUE ANY ADVISORIES FOR SNOW/BLOWING SNOW ON THIS SHIFT...BUT THE AREA
ALONG INTERSTATE 35 TO THE TWIN PORTS...INCLUDING ALL OF
NORTHWEST WISCONSIN AND THE ARROWHEAD OF MINNESOTA MAY SEE
CONDITIONS THAT WARRANT AN ADVISORY LATE TONIGHT INTO MONDAY. WE
WILL WAIT FOR ANOTHER SET OF MODELS AND LET THE NEXT CREW ADJUST
AS NEEDED.

WE ARE CONFIDENT ENOUGH TO ISSUE A WATCH FOR ASHLAND/IRON COUNTIES
FOR MONDAY INTO MONDAY NIGHT. SNOW FROM THE LOW WILL OCCUR
MONDAY...THEN THE LAKE WILL CONTRIBUTE ADDED SNOWFALL MONDAY
NIGHT. A GOOD FETCH WILL EXIST WITH 850MB TEMPS DROPPING TO AROUND
-12C CREATING FAVORABLE INSTABILITY.

TEMPERATURES MONDAY WILL PEAK EARLY...THEN DROP THROUGH THE DAY
AS THE COLD AIR POURS IN.

AREAS OF DENSE FOG CONTINUED THIS MORNING AND WE WILL EXTEND THE
ADVISORY THROUGH NOON AND INCLUDED THE NORTH SHORE ZONES AS WELL.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 AM CST SUN NOV 23 2014

LAKE EFFECT SNOW EVENT ALONG THE SOUTH SHORE OF LAKE SUPERIOR SHOULD
BE WINDING DOWN AT THE BEGINNING OF THE EXTENDED PERIOD TUESDAY
MORNING. THERE MAY BE SOME LINGERING LIGHT SNOW SHOWERS TUESDAY..BUT
AS 925/850 THERMAL TROF TRANSLATES EAST OF THE WRN GRT LAKES AND
WINDS BACK TO MORE WESTERLY AND DIMINISH IN SPEED AS GRADIENT
RELAXES..HEAT FLUX OFF THE LAKE SHOULD WANE FAIRLY RAPIDLY. THE
POTENTIAL FOR ANY ADDITIONAL SIG ACCUMULATION OVER BAYFIELD/IRON/
ASHLAND COUNTIES AFTER TUESDAY MORNING APPEARS RATHER SMALL.

MAIN ITEM OF ATTENTION THEN BECOMES WHAT INCREASINGLY LOOKS LIKE A
RATHER POTENT CLIPPER-TYPE SYSTEM FOR TUESDAY NITE/WEDNESDAY. MOST
OF THE AVAILABLE GUIDANCE BRINGS A VERY STRONG VORT MAX FROM N
DAKOTA TUE NITE TO S CENT WI BY WED EVENING..AND THE ASSOCIATED
SURFACE LOW TRACK ROUGHLY ALONG I94. IF CURRENTLY FORECASTED MODEL
MASS FIELDS ARE IN THE BALL PARK..A 6-9 HOUR PERIOD OF EXTREMELY
STRONG FORCING FOR ASCENT WILL TRANSLATE ACROSS THE CENTRAL AND
SOUTHERN DULUTH CWA.  CURRENT MODEL PROGS ALSO SUGGEST THE POTENTIAL
FOR STRONG MESOSCALE FRONTOGENESIS FORCING..IMPLYING THE POTENTIAL
FOR A NARROW BAND OF ENHANCED ACCUMULATIONS SOMEWHERE.  THE TWO
LIMITING FACTORS APPEAR TO BE THERMAL PROFILES..WHICH ARE NOT IN THE
IDEAL CRYSTAL GROWTH REGIMES..AND THE SPEED OF THE SYSTEM..WHICH WILL
ACT TO LIMIT THE DURATION.  STILL..IT APPEARS THAT THERE IS SOME
POTENTIAL FOR 4-5 INCH PLUS AMOUNTS..AND PERHAPS HEAVIER IF STRONG
FGEN EVOLVES AS CURRENTLY SUGGESTED BY THE MODELS.

ARCTIC AIR WILL THEN SPILL SOUTHWARD INTO THE REGION AGAIN IN THE
WAKE OF THE CLIPPER SYSTEM..WITH SCATTERED SNOW
SHOWERS/FLURRIES..AND THE POTENTIAL FOR MORE LAKE EFFECT
ACCUMULATIONS ON THE SOUTH SHORE. A SECONDARY REINFORCING SHOT OF
COLD AIR IS EXPECTED SOMETIME AROUND FRIDAY..WITH SIMILAR EFFECTS ON
SENSIBLE WEATHER.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1140 CST SUN NOV 23 2014

THE WIDESPREAD LIFR/IFR CONDITIONS OVER NE
MINNESOTA AND NW WISCONSIN LATE THIS MORNING IS EXPECTED TO
CONTINUE INTO THIS EVENING. THE EXCEPTION IS AT KBRD...WHICH WILL
SEE A PERIOD OF MVFR THROUGH THIS AFTERNOON BEFORE CONDITIONS
DETERIORIATE AGAIN THIS EVENING. THERE WILL BE MINIMAL IMPROVEMENT
ELSEWHERE WITH CONDITIONS ALSO DETERIORIATING LATE THIS AFTERNOON
AND THIS EVENING. DRIZZLE AND -SN WILL DEVELOP LATE THIS AFTERNOON
AND EARLY THIS EVENING WITH A TRANSITION TO -SN OVERNIGHT FROM
WEST TO EAST. GUSTY NNW WINDS WILL DEVELOP LATE TONIGHT AND MONDAY
MORNING. THE COMBINATION OF -SN/BLSN AND LOW CIGS WILL LIKELY
MAINTAIN WIDESPREAD IFR/MVFR CONDITIONS THROUGH MONDAY MORNING.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  41  24  26   8 /  30  70  70  30
INL  38  18  18   2 /  20  50  60  10
BRD  40  19  21   7 /  20  50  50  10
HYR  48  28  29   8 /  60  80  80  50
ASX  47  30  31  13 /  50  90 100  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ020-021-
     037-038.

WI...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ001>004-
     006>009.

     WINTER STORM WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING
     FOR WIZ003-004.

LS...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 10 AM CST TUESDAY FOR
     LSZ121-148.

     SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM CST TUESDAY FOR
     LSZ141>147.

     GALE WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR
     LSZ140.

&&

$$

UPDATE...STEWART
AVIATION...GROCHOCINSKI







U.S. Dept. of Commerce
NOAA National Weather Service
1325 East West Highway
Silver Spring, MD 20910
E-mail: w-nws.webmaster@noaa.gov
Page last modified: May 16, 2007
NATIONAL WEATHER SERVICE: for Safety, for Work, for Fun - FOR LIFE