Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 150919
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
419 AM CDT TUE APR 15 2014

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 418 AM CDT TUE APR 15 2014

THE FOCUS IS ON A STORM SYSTEM WHICH COULD BRING HEAVY SNOW TO
PARTS OF THE FORECAST AREA LATE TONIGHT THROUGH WEDNESDAY
NIGHT...PRIMARILY THE SOUTHERN HALF OF THE FORECAST AREA.
CONFIDENCE IN SNOWFALL AMOUNTS...AND WHERE THE HEAVIEST SNOWFALL
WILL OCCUR...IS INCREASING. HOWEVER...SINCE THERE IS STILL SOME
DIFFERENCES IN THE TRACK AND TIMING IN THE MODELS...AND SINCE
THESE SPRING WINTRY WEATHER SYSTEMS CAN BE TRICKY WITH
TEMPERATURES AND MELTING/COMPACTING OF SNOWFALL...I DECIDED TO
MAINTAIN THE WINTER STORM WATCH. THE DAY SHIFT SHOULD HAVE A
BETTER ABILITY AT NARROWING DOWN THE DETAILS OF THIS STORM.

TODAY...COLD BUT SUNNY. HIGH PRESSURE IN THE NORTHERN PLAINS EARLY
THIS MORNING WILL SHIFT INTO THE NORTHLAND BY THIS AFTERNOON. THIS
SHOULD PROMOTE SUNNY SKIES FOR MUCH OF THE FORECAST AREA
TODAY...OR AT LEAST THE WESTERN TWO THIRDS. THE ARROWHEAD AND NW
WISCONSIN WILL PROBABLY SEE SOME SCATTERED CUMULUS IN THIS COOL NW
FLOW. IRON COUNTY IN NW WISCONSIN COULD SEE A LITTLE DUSTING FROM
LAKE EFFECT SNOW. HIGH TEMPERATURES WILL BE ABOUT 20 DEGREES BELOW
NORMAL FOR THIS TIME OF THE YEAR. MEANWHILE...A LOW PRESSURE
SYSTEM IN SE ALBERTA EARLY THIS MORNING WILL MOVE INTO THE
AMERICAN NORTHERN HIGH PLAINS AND STRENGTHEN/ORGANIZE TODAY. THIS
IS THE STORM SYSTEM THAT WILL BE AFFECTING THE NORTHLAND LATE
TONIGHT AND WEDNESDAY. THERE COULD BE SOME INCREASING HIGH CLOUDS
ACROSS THE WESTERN FORECAST AREA LATE THIS AFTERNOON AND EARLY
THIS EVENING BEFORE SUNSET IN ADVANCE OF THIS APPROACHING STORM
SYSTEM.

TONIGHT...THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THE LOW
PRESSURE SYSTEM WILL MOVE TO THE SE SOUTH DAKOTA AREA BY LATE
TONIGHT. IT WILL BE ACCOMPANIED BY A SHORTWAVE THAT WOULD WILL
HAVE CROSSED THE PACIFIC NW AND ROCKIES TODAY. THE MODELS ARE
INDICATING THAT A BAND OF LOW/MID LEVEL FRONTOGENESIS WILL SET UP
NE OF THE LOW...AND WILL LIKELY BEGIN TO BRING SNOW INTO THE
WESTERN AND SOUTHERN FORECAST OVERNIGHT. HOWEVER...THE GEM IS
FASTER AND MORE SOUTH WITH THE SNOW THAN THE OTHER MODELS. THE NAM
IS MORE FOCUSED WITH THE SNOW BAND...AND IS PROBABLY PICKING UP
THE MORE NARROW BAND THAT THE FRONTOGENETICAL BAND WILL LIKELY
PROMOTE. THE ECMWF IS MUCH LIGHTER IN PCPN AND SNOWFALL AMOUNTS
THAN THE GFS/GEM/NAM. CONSIDERING ALL THIS...I LEANED ON A BLEND
OF THE NAM AND GFS.

WEDNESDAY...THIS IS WHERE THE MODELS BEGIN TO LOSE AGREEMENT WITH
THE TRACK AND TIMING OF THE MOVEMENT OF THE SURFACE LOW. THE ECMWF
AND GEM ARE SIGNIFICANTLY...ABOUT 3 TO 6 HOURS OR SO...SLOWER THAN
THE GFS AND NAM. HOWEVER...THE GENERAL TRACK SHOULD BE FROM SE
SOUTH DAKOTA TO SE MINNESOTA OR WEST CENTRAL WISCONSIN. THE GEM
AND ECMWF AND SLOWER WITH THE TRACK THAN THE GFS AND NAM. WHILE I
USED A BLEND FOR PCPN CHANCES AND AMOUNTS...I LEANED A LITTLE BIT
MORE ON THE GFS AND NAM. THE GFS AND NAM ARE INDICATING LOW/MID
LEVEL FRONTOGENESIS WILL LIKELY INTENSIFY ACROSS THE SE AND SOUTH
CENTRAL FORECAST AREA. DEPENDING ON WHERE THIS FRONTOGENETICAL
BAND SETS UP...IT COULD MEAN THE DIFFERENCE OF SEVERAL INCHES OR
MORE OF SNOW FOR ANY PARTICULAR PLACE IN THE FORECAST AREA...AND
THAT IT IMPLIES THERE COULD BE A SHARP CUTOFF IN SNOWFALL AMOUNTS.
THE NAM AND SREF INDICATE THERE COULD BE GOOD LIFT AND MOISTURE IN
THE DENDRITIC GROWTH ZONE...WHICH COULD PROMOTE HIGHER SNOWFALL
RATES AND AMOUNTS. SNOWFALL RATES IN THE STRONGER BAND THAT SHOULD
SET UP COULD EXCEED ONE INCH PER HOUR. THE NAM AND GFS ARE ALSO
SHOWING WARMER AIR ALOFT MOVING INTO THE SE FORECAST AREA DURING
THE AFTERNOON. THIS COULD RESULT IN SOME SNOW MIXED WITH RAIN...OR
EVEN JUST RAIN...FOR SOME AREAS...INCLUDING PHILLIPS...PARK FALLS
AND WINTER. THE RAIN COULD MELT SOME OF THE SNOWFALL ALREADY ON
THE GROUND AND CUT DOWN ON TOTAL STORM SNOWFALL. THERE WILL BE
INCREASING EAST TO NORTHWEST WINDS WEDNESDAY...ESPECIALLY NEAR
LAKE SUPERIOR. THE COMBINATION OF THE WIND AND HEAVIER SNOWFALL
RATES COULD CAUSE LOW VISIBILITY AT TIMES.

OVERALL...I STILL HAVE SOME CONCERNS ABOUT THE EXACT TRACK AND
TIMING OF THE SURFACE LOW...WHERE AND WHEN WILL THE FRONTOGENETICAL
BANDS SET UP...WHETHER THERE WILL BE ANY RAIN...AND WHETHER THE
ROADS WILL BE WARM ENOUGH TO MELT ANY SNOW AND CUT DOWN ON TOTAL
SNOWFALL AMOUNTS. THIS IS WHY I AM MAINTAINING THE WATCH...AND
HOPEFULLY THE WATCH WILL NARROW DOWN THE DETAILS EVEN MORE.
I AM GETTING MORE CONFIDENT THOUGH IN HIGHER SNOWFALL
ACCUMULATIONS. THE LOW TEMPERATURES TONIGHT ARE EXPECTED TO BE
WELL BELOW FREEZING. THE SNOW AND CLOUD COVER THEN MOVE IN LATE
TONIGHT. THIS SHOULD PREVENT MUCH WARMING WEDNESDAY...AND THE
ROADS COULD REMAIN COLD ENOUGH TO ALLOW PLENTY OF SNOW
ACCUMULATION...ESPECIALLY IF THERE IS THICK CLOUD COVER TO
INSULATE THE LOWEST LAYERS. AT THIS TIME...IT APPEARS MUCH OF THE
SOUTHERN FORECAST AREA COULD SEE 6 TO 12 INCHES. THE NORTHERN
FORECAST AREA COULD SEE LITTLE IF ANY SNOWFALL.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM CDT TUE APR 15 2014

THE LOW WILL CONTINUE TO MOVE NORTHEAST WEDNESDAY NIGHT AND WILL
BE IN THE NORTHERN GREAT LAKES BY THURSDAY MORNING. THE SNOW
WILL END WEST TO EAST ACROSS NW WI WITH AN ADDITIONAL 2-4 INCHES
EXPECTED BEFORE ENDING AFTER MIDNIGHT. THERE WILL BE SOME
LINGERING FLURRIES OR LIGHT SNOW ACROSS THE ARROWHEAD AND NW
THURSDAY MORNING BEFORE ENDING BY NOON IN THE WRAP-AROUND. AN AREA
OF HIGH PRESSURE WILL BUILD INTO THE FORECAST AREA THURSDAY
AFTERNOON AND MOVE EAST THROUGH SATURDAY. TEMPERATURES WILL BE
SLOWLY ON THE REBOUND WITH 40S BY SATURDAY. A SERIES OF SHORTWAVES
WILL MOVE THROUGH THE FORECAST AREA SATURDAY THROUGH MONDAY
BRINGING A CHANCE FOR RAIN DURING THE DAY AND A MIXTURE OF
RAIN/SNOW AT NIGHT. HIGH TEMPERATURES WILL BE IN THE 50S SATURDAY
INTO NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1217 AM CDT TUE APR 15 2014

CURRENT VFR CONDITIONS WITH NORTHWEST FLOW EXPECTED TO CONTINUE
REMAINDER OF THE NIGHT WITH GRADUALLY DIMINISHING WINDS. TUESDAY
WINDS TO GRADUALLY SHIFT AROUND TO SOUTHEAST. CLOUDS TO GRADUALLY
SPREAD INTO THE AREA FROM THE WEST AS THE NEXT STORM SYSTEM
SPREADS TOWARDS THE AREA. VFR CIGS TO CONTINUE THROUGH AT LEAST
04Z TONIGHT...WHEN SOME MVFR CONDITIONS WITH -SN SHOULD APPROACH
KBRD.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  32  20  28  20 /   0  60  90  40
INL  27  13  35  16 /   0  20  20  20
BRD  35  25  34  22 /   0  70  90  30
HYR  32  19  35  25 /   0  70  90  60
ASX  31  19  32  24 /   0  50  90  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING
     FOR MNZ020-033>038.

WI...WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING
     FOR WIZ001>004-006>009.

LS...NONE.
&&

$$

SHORT TERM...GROCHOCINSKI
LONG TERM...STEWART
AVIATION...STEWART







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