Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 212358
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
558 PM CST FRI NOV 21 2014

.UPDATE...
ISSUED AT 533 PM CST FRI NOV 21 2014

HAVE REMOVED MENTION OF FZDZ UNTIL LATE TONIGHT...AND HAVE IT
PRIMARILY CONFINED TO THE BORDERLAND/IRON RANGE AND NORTHERN
WISCONSIN. LATEST SAT IMAGERY AND SFC OBSERVATIONS SHOW TWO AREAS
OF LOW CLOUDS/FREEZING DRIZZLE THAT WILL MOVE INTO THE REGION
OVERNIGHT.

THE FIRST WILL BE ASSOCIATED WITH A SHORT WAVE TRACKING EAST INTO
ONTARIO. LATEST NAM/WRF GUIDANCE SUGGEST THE LOW CLOUDS AND
POTENTIAL FOR FZDZ FROM THIS WAVE SKIRT ACROSS THE
BORDERLAND/ARROWHEAD AFTER MIDNIGHT.

FOCUS TURNS TO THE STRONG WAA WITH A 40-50 KT LLJ AND INCREASING
MOISTURE THAT PUSHES INTO THE SRN HALF OF THE CWA THROUGH THE REST
OF THE NIGHT. CURRENT SAT IMAGERY AND SFC OBSERVATIONS SHOW THE
LOW CEILINGS ARE STILL CONFINED TO LOCATIONS IN IOWA...CRUISING
NORTH INTO SRN MN. TRIED TO CAPTURE A DECENT TIME-TRACK ON THE
LEADING EDGE OF THE LOW CLOUDS/DZ...WHICH SUGGESTS AN ARRIVAL TIME
INTO THE WISCONSIN ZONES AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 309 PM CST FRI NOV 21 2014

COMPLEX PATTERN OVER THE WEEKEND WITH ALL TYPES OF WINTRY PRECIP
POSSIBLE. TEMPERATURES WILL ACTUALLY REACH ABOVE FREEZING AND
POSSIBLY SLIGHTLY ABOVE NORMAL.

ON THE SYNOPTIC SCALE TWO UPPER LEVEL SYSTEMS WILL MERGE INTO A
STRONG STORM OVER THE GREAT LAKES REGION THIS WEEKEND. TODAY SOUTH
TO SOUTHWESTERLY FLOW AT LOW LEVELS WILL BRING WARMER AND MORE MOIST
AIR TO THE REGION. A SURFACE LOW TRAVERSING WEST TO EAST ACROSS
CENTRAL MANITOBA INTO NORTHERN ONTARIO AND A SURFACE HIGH OVER THE
OHIO VALLEY GRADUALLY MOVE EAST INTO THE MID-ATLANTIC WILL LEAD TO A
STRONGER PRESSURE GRADIENT OVER THE REGION AND THUS GUSTY WINDS. AT
MID AND UPPER LEVELS FLOW WILL BE NEARLY ZONAL THROUGH SATURDAY
AFTERNOON WHEN A DEEPENING UPPER LOW MOVES EAST ACROSS THE NORTHERN
PLAINS LEADING TO SOUTHWESTERLY FLOW.

TODAY...SUNSHINE BREAKING OUT THROUGH THE EARLY AFTERNOON FOLLOWED
BY A STRATUS DECK RAPIDLY DEVELOPING IN THE MID/LATE AFTERNOON DUE
TO MOIST LOW LEVEL AIR ADVECTING IN. WINDS WILL BE GUSTY WHILE THE
SUN IS OUT DUE TO A 50-60KT LOW LEVEL JET AT JUST 2-4 KFT AGL MIXING
DOWN TO CREATE GUSTS NEAR 30KTS AT THE SURFACE. TEMPS WILL BE MUCH
WARMER THAN YESTERDAY...RISING TO NEAR 30 AT A FEW LOCATIONS.

TONIGHT...STRATUS WILL BE QUICK TO FORM ACROSS THE REGION. NAM IS
THE MOST AGGRESSIVE WITH A CLOUD DECK DEVELOPING ACROSS THE REGION
RAPIDLY DEVELOPING BY MIDNIGHT...AND SOME LIFT IN LOW LEVELS
COMBINED WITH THE ABUNDANCE OF LOW LEVEL MOISTURE IS EXPECTED TO
LEAD TO FREEZING DRIZZLE AND FREEZING RAIN. THE BEST CHANCE FOR
FREEZING RAIN WILL BE IN THE ARROWHEAD REGION OF NORTHERN MN AND
MUCH OF NORTHWEST WISCONSIN WHERE GOOD LOW LEVEL LIFT WILL DEVELOP
DUE TO A FEW SUBTLE MID-LEVEL DISTURBANCES MOVING ACROSS IN THE
FLOW. SOME SLEET MAY MIX IN ACROSS NORTHWEST WISCONSIN. ICE
ACCUMULATION IS NOT EXPECTED TO BE SIGNIFICANT...BUT ELEVATED
SURFACES COULD ACCUMULATE A LIGHT GLAZE. WINDS WILL WEAKEN
SIGNIFICANTLY ONCE THE INVERSION SETS UP...OUT OF THE SOUTHWEST TO
SOUTH AT 5 TO 10 KTS. TEMPERATURES WILL BE STEADY THROUGH THE NIGHT
DUE TO WARM AIR ADVECTION ALOFT AND STRATUS DECK...IN THE LOW TO MID
20S OVERNIGHT RISING TO THE UPPER 20S BY SATURDAY MORNING.

SATURDAY...SOME SUN IS EXPECTED TO BREAK OUT WITH DRIZZLE COMING TO AN
END IN THE MORNING HOURS AND TEMPERATURES WARM UP TO ABOVE FREEZING.
TEMPS RISING ABOVE FREEZING DURING THE DAY WILL MELT ANY ICE
ACCUMULATION...AND DEPENDING ON CLOUD COVER HIGHS MAY REACH THE
UPPER 30S. THERE IS SOME MODEL DISCREPANCIES ON IF THE STRATUS DECK
WILL STICK AROUND ALL DAY OR IF THERE WILL BE BREAKS...WITH THE NAM
AGAIN AGGRESSIVE ABOUT KEEPING CLOUDS MOST OF THE DAY WHILE THE
GFS/GEM/ECMWF ARE MORE SUN THAN CLOUDS IN THE AFTERNOON. LEANED
TOWARDS THE NAM GIVEN CLIMATOLOGY IN THIS KIND OF PATTERN...BUT
CONFIDENCE IS LOWER THAN NORMAL. WINDS LIGHT ALL DAY OUT OF THE
SOUTH AT 5 TO 10 KTS.

SATURDAY NIGHT...THE MAIN SURFACE LOW WILL MOVE EAST TOWARDS THE
REGION WITH A WARM FRONT LIFTING BEGINNING TO LIFT NORTH THROUGH
CENTRAL MN/WI. ANOTHER ROUND OF FREEZING RAIN/DRIZZLE AND POSSIBLY
SLEET TRANSITIONING TO RAIN IS EXPECTED OVERNIGHT...BUT MORE
WIDESPREAD THAN FRIDAY NIGHT AS DEEPER MOISTURE IS ADVECTED IN AND
THE BEST LARGE-SCALE LIFT DEVELOPS. WINDS WILL BE LIGHT OUT OF THE
SOUTH TO SOUTHEAST AS THE WARM FRONT LIFTS NORTH. AGAIN...ICE
ACCUMULATION IS EXPECTED TO BE MINIMAL AS TEMPS RISE ABOVE FREEZING
THROUGH THE NIGHT DUE TO WARM AIR ADVECTION.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 309 PM CST FRI NOV 21 2014

THE MAIN FOCUS FOR THE LONG TERM IS THE EVOLUTION OF THE SYSTEM FOR
THE END OF THE WEEKEND AND EARLY IN THE WORK WEEK. THE MODELS
CONTINUE TO OPT FOR A SYSTEM THAT DOES NOT QUITE PHASE BETWEEN THE
NORTHERN STREAM AND THE STRONGER SOUTHERN STREAM. THE STRONG UPPER
LEVEL SYSTEM WAS NOW MOVING THROUGH SOUTHERN CALIFORNIA...AND
ACCORDING TO THE ECMWF IT SHOULD REACH NORTHEASTERN TEXAS BY SUNDAY
MORNING. A STRONG LLJ IS EXPECTED TO DEVELOP AHEAD OF THE UPPER
LEVEL LOW AND STRONG SHORTWAVE...WITH THE ECMWF LIFTING THE UPPER
LEVEL SHORTWAVE INTO WISCONSIN AND UPPER MICHIGAN BY 12Z MONDAY.
MEANWHILE...THE UPPER LEVEL LOW IN THE NORTHERN STREAM PUSHES INTO
CENTRAL MN BY 12Z MONDAY. THIS STORM STILL BEARS WATCHING...BUT AT
THIS TIME...THE MODELS DO NOT PHASE THE MOISTURE AND UPPER LEVEL
ENERGY BETWEEN THE TWO UPPER LEVEL SYSTEMS. IF IT DOES...IT COULD
EVOLVE INTO A MAJOR STORM SYSTEM FOR THE WESTERN GREAT LAKES. GIVEN
THE CURRENT MODEL TRENDS...IT LOOKS LIKE MAINLY CHANCE TYPE LIQUID
PRECIPITATION OR AREAS OF DRIZZLE/FREEZING DRIZZLE FOR THE START OF
THE EXTENDED TIME PERIOD...FOLLOWED BY A GRADUAL TRANSITION TO A MIX
AND THEN SNOW BY EARLY IN THE WORK WEEK. THERE SHOULD BE AREAS OF
BLOWING SNOW ON MONDAY AS WELL...AS THE STORM SYSTEM INTENSIFIES.
LAKE EFFECT SNOW WILL THEN BE THE MAIN THREAT THROUGH THE MIDDLE OF
THE WEEK...WITH COOL WEATHER EXPECTED FOR MUCH OF THE WORK WEEK.
TEMPS SHOULD START TO RECOVER BY THE END OF THE WEEK...AS UPPER
LEVEL RIDGING PUSHES INTO THE REGION.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 533 PM CST FRI NOV 21 2014

CHALLENGING FORECAST WITH LOWER THAN AVERAGE CONFIDENCE ON TIMING
IN THE LOW CLOUDS AND FZDZ POTENTIAL LATE TONIGHT/SAT MORNING. LATEST
SAT IMAGERY AND SFC OBSERVATIONS SHOW TWO AREAS OF MVFR CIGS AND POSSIBLE
FZDZ THAT WILL MOVE INTO THE REGION OVERNIGHT.

THE FIRST WILL BE ASSOCIATED WITH A SHORT WAVE TRACKING EAST INTO
ONTARIO. LATEST GUIDANCE SUGGESTS THE SRN EDGE OF THE LOW CLOUDS
AND PATCHY FZDZ FROM THIS WAVE SKIRT ACROSS THE
BORDERLAND/ARROWHEAD AFTER MIDNIGHT.

FOCUS TURNS TO THE STRONG WAA WITH A 40-50 KT LLJ AND INCREASING
MOISTURE THAT PUSHES INTO THE SRN HALF OF THE CWA THROUGH THE REST
OF THE NIGHT. CURRENT SFC OBSERVATIONS SHOW THE LEADING EDGE OF
THE MVFR CEILINGS CRUISING NORTH INTO SRN MN. AT THIS
TIME...EXPECTING THIS STRATUS AND POTENTIAL FOR FZDZ TO LIFT INTO
NRN WISCONSIN....INCLUDING THE KHYR AREA...AFTER MIDNIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  24  34  30  39 /  20  20  30  40
INL  25  33  27  36 /  20  20  30  30
BRD  25  35  29  37 /  10  10  20  20
HYR  23  37  31  42 /  10  20  50  50
ASX  26  37  31  43 /  10  10  40  50

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 AM CST SATURDAY FOR LSZ143>146.

     GALE WARNING UNTIL 4 AM CST SATURDAY FOR LSZ121-140>142-147-148.

&&

$$

UPDATE...GRANING
SHORT TERM...MOORE
LONG TERM...DAP
AVIATION...GRANING





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