Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 191741 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1141 AM CST WED NOV 19 2014

.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 408 AM CST WED NOV 19 2014

MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE SCATTERED
SNOW SHOWERS TODAY...PRODUCING AROUND AN INCH OF ACCUMULATION OVER
THE NORTHLAND...AND THE POTENTIAL FOR LAKE EFFECT SNOW ALONG THE
SOUTH SHORE...ESPECIALLY INTO IRON COUNTY ONCE AGAIN WHERE
SIGNIFICANT ACCUMULATION IS POSSIBLE. WILL ALSO HIGHLIGHT THE COLD
TEMPERATURES THROUGH THE SHORT TERM.

UPPER S/W AND ASSOCIATED SFC TROUGH WILL CONTINUE TO MOVE ACROSS
THE UPPER MIDWEST INTO THE WRN GREAT LAKES TODAY AND PRODUCE
SCATTERED SNOW SHOWERS THROUGHOUT THE NORTHLAND. WIDESPREAD AMTS
OF ONE HALF TO ONE INCH ARE POSSIBLE THROUGH THE AFTERNOON. AS
THIS SYSTEM EXITS TO THE EAST...THE NLY FLOW ON THE BACK SIDE OF
THE SYSTEM WILL PULL DOWN AN ARCTIC AIR MASS ACROSS THE
RELATIVELY WARM WATERS OF LAKE SUPERIOR AND MODIFY THE LOW LEVELS
ENOUGH TO GET THE LAKE EFFECT SNOW MACHINE GOING ONCE AGAIN ACROSS
THE SOUTH SHORE. THERMAL PROFILES BECOME RATHER STEEP THIS
EVENING AND THUR MORNING...WITH LAKE INDUCED CAPE VALUES 400 TO
700 J/KG AND BL HEIGHTS AROUND 4-5K FT AGL. THE LIMITING FACTOR
WILL BE THE TRAJECTORIES ACROSS THE LAKE AND RELATIVE SHORT
DURATION OF THE EVENT. BL WINDS WILL CONTINUE TO HAVE A SLIGHT WLY
COMPONENT AND TEND TO FAVOR AREAS INTO THE U.P. RATHER THAN ALONG
THE SOUTH SHORE OF NRN WI. HOWEVER...THERE SHOULD BE ENOUGH OF A
NLY COMPONENT TO DEVELOP HEAVY SNOW BANDS THAT WILL TRACK INTO
PARTS OF NRN IRON COUNTY...AND ALSO OVER NRN BAYFIELD CNTY.
EXPECTING AROUND 4 TO 7 INCHES AROUND THE MONTREAL AND GILE AREAS
OF NRN WI NEAR THE MI/WI BORDER. HAVE ISSUED A LAKE EFFECT SNOW
ADVISORY FROM LATE THIS AFTERNOON THROUGH THURSDAY. WILL ALSO SEE
A GOOD 2 TO 4 INCHES POSSIBLY IN NRN BAYFIELD COUNTY. EVEN WITH A
SHORT FETCH OVER LS...SHOULD BE ABLE TO DEVELOP AT LEAST A FEW
WEAK LAKE BANDS FROM PORT WING TO WASHBURN AND NWD TO CORNUCOPIA.

OTHERWISE...HIGH PRESSURE WILL BUILD IN FROM THE WEST AS THE
SYSTEM EXITS TO THE EAST...ALONG WITH A DRIER AIR MASS. THE COLD
CYCLONIC FLOW ALOFT WILL PERSIST THROUGH THE SHORT TERM AND ALLOW
SKIES TO REMAIN MOSTLY CLOUDY...BUT KEEP TEMPERATURES ON THE COOL
SIDE. HIGHS TODAY WILL REMAIN IN THE TEENS...WITH OVERNIGHT LOWS
TONIGHT INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO. TEMPS REMAIN
QUITE COLD ON THURSDAY WITH HIGHS ONLY INTO THE LOWER TEENS.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 AM CST WED NOV 19 2014

A NW FLOW OVER LAKE SUPERIOR IS BEGINNING TO BREAK DOWN THURSDAY
EVENING AS DRIER AIR IS MOVING INTO THE FA FROM HIGH PRESSURE.
MAINTAINED THE PREVIOUS FORECAST IN THE EVENING WITH POPS OVER THE
NORTHERN HALF OF IRON COUNTY. AFTER 06Z...REMOVED THE POPS AS THE
FLOW TURNS WLY...DRY AIR AND WAA TAKE OVER. HIGH PRESSURE COVERS THE
REST OF THE AREA THURSDAY NIGHT. SFC/UPPER LEVEL RIDGING COVER THE
WESTERN GREAT LAKES ON FRIDAY. WAA UNDERNEATH THE RIDGE WILL ALLOW
MAX TEMPS INTO THE 20S WITH UPPER TEENS IN THE FAR EASTERN EDGE OF
THE FA. THE WAA STRENGTHENS FRIDAY NIGHT WHILE A MID LEVEL TROF
MOVES INTO WESTERN MN. HAVE NO PCPN IN THE EVENING AS DRY ATMOSPHERE
NEEDS TO MOISTEN UP. AFTER 06Z...HAVE SMALL POPS OVER THE EASTERN
EDGE OF THE FA WHERE FORECAST SOUNDINGS ARE INDICATING SOME LIGHT
SNOW OR SLEET MAY FORM. THE WAA CONTINUES ON SATURDAY WITH SW FLOW
ALOFT. KEPT THE PREVIOUS FORECAST OF POPS OVER THE EASTERN THIRD OF
THE FA WHERE BEST MOISTURE IS LOCATED. MIXED PCPN IS EXPECTED WITH
THE WARM AIR OVER THE COLD BOUNDARY LAYER. MODELS BEGIN TO DIVERGE
SATURDAY NIGHT...BUT COME INTO BETTER AGREEMENT BY SUNDAY NIGHT. LOW
PRESSURE ORGANIZES IN THE CENTRAL PLAINS WHILE AN UPPER LOW DIGS
INTO THE NORTHERN PLAINS. THE ECMWF KEEPS A BIT DRIER AIR IN PLACE
WHILE THE GFS MOISTENS THINGS UP. HAVE LEANED A BIT TOWARDS THE
ECMWF WHICH HAS SOME AGREEMENT FROM THE GEM AND DGEX. SOUNDINGS
INDICATE ANY PCPN THAT DOES FALL WILL BE -FZRA POSSIBLY MIXED WITH
SLEET. ON SUNDAY THE SFC LOW DEEPENS AS IT LIFTS TO NEAR THE WI/IL
BORDER. MEANWHILE...THE UPPER LOW CLOSES OFF. PCPN TYPE ISSUES
CONTINUE ON SUNDAY WITH SOME -FZRA/-SN OR SLEET POSSIBLE IN THE
MORNING OVER MUCH OF THE AREA WITH -RA FROM PINE COUNTY EWD TO PRICE
COUNTY. MODEL DIFFERENCES IN THE THERMAL PROFILE ON SUNDAY AFTERNOON
KEEPS THE MIXED PCPN OVER THE WESTERN HALF WITH MOSTLY RAIN OVER THE
EASTERN HALF OF THE FA. ON MONDAY...THE MODELS POINT TOWARD THE
UPPER LOW AND SFC LOW BECOMING VERTICALLY STACKED. THE ECMWF HOWEVER
IS DEEPER THAN THE GFS. A WINDY DAY IS EXPECTED...BUT THE PCPN TYPE
WILL BE ALL SNOW AS COLD AIR IS PULLED DOWN FROM NORTHERN CANADA.
THE ECMWF ALSO HAS MORE QPF THAN THE GFS WHICH WILL AFFECT THE
AMOUNTS. THIS SYSTEM BEGINS TO LOOSEN ITS GRIP ON THE AREA MONDAY
NIGHT AS HIGH PRESSURE ARRIVES FROM THE WEST. MORE LIGHT SNOW IS
EXPECTED MONDAY NIGHT BEFORE ENDING ON TUESDAY WITH THE HIGH MOVING
INTO THE AREA.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1137 AMCST WED NOV 19 2014

MVFR CIGS WITH SNOW SHOWERS WILL BE FOUND ACROSS THE FORECAST AREA
THROUGH ABOUT 02Z. OCNL VSBYS BLO 4SM IN SOME SNOW SHOWERS. EXPECT
MAINLY VFR AFT 10Z. WINDS FROM 290 TO 310 DEGREES WILL INCREASE
TO G25 THIS AFTERNOON AND DECREASE TO BLO 25 KTS AFT 02Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  19   2  13   0 /  60  10   0   0
INL  17  -1  10  -5 /  50  20   0  10
BRD  19   2  14  -3 /  20  10   0   0
HYR  20   3  14  -6 /  60  20  10   0
ASX  23   6  16   0 /  70  40  40  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM CST
     THURSDAY FOR WIZ004.

LS...SMALL CRAFT ADVISORY UNTIL 6 AM CST THURSDAY FOR LSZ121-145>148.

&&

$$

SHORT TERM...BJT
LONG TERM...GSF
AVIATION...CLC







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