Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 011145
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
645 AM CDT TUE SEP 1 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CDT TUE SEP 1 2015

A WEAKENING SURFACE BOUNDARY WAS MOVING SLOWLY THROUGH THE
NORTHLAND WITH WEAK LOW LEVEL CONVERGENCE. AREA RADARS HAVE
DEPICTED WEAK ECHOES THIS MORNING AND THERE HAS BEEN A FEW
OBSERVATIONS PICKING UP SOME LIGHT RAIN. WE EXPECT SOME LIGHT
SHOWERS TO CONTINUE THIS MORNING BUT FOR LITTLE ACCUMULATION. WE
LEFT THE MENTION OF THUNDER OUT THIS MORNING DESPITE MUCAPE OF
500-1000J/KG OVER OUR EASTERN ZONES. THE FORCING HAS BEEN JUST TOO
WEAK. FOG HAS ONCE AGAIN FORMED THIS MORNING AND THAT SHOULD LIFT
BETWEEN 8 AM AND 930 AM FOR MOST AREAS. WE LEFT A MENTION OF A
SHOWER/STORM OVER A PORTION OF NORTHWEST WISCONSIN THIS AFTERNOON
AND WENT DRY ELSEWHERE. IT WILL REMAIN WARM WITH HIGHS 80 TO 85.
IT WILL BE LESS HUMID OVER MUCH OF NORTHEAST MINNESOTA TODAY...BUT
REMAIN MUGGY OVER MUCH OF NORTHWEST WISCONSIN.

A SHORTWAVE WILL LIFT NORTHEAST AND MAINLY IMPACT OUR SOUTHERN
ZONES TONIGHT. WE HAVE A MENTION OF SHOWERS/STORMS FOR PORTIONS OF
THE NORTHLAND AND MAY HAVE TO INCREASE THE CHANCE OVER OUR
SOUTHERN ZONES INCLUDING ALL OF NORTHWEST WISCONSIN IF WE GET A
BIT BETTER AGREEMENT AMONG THE MODELS.

THERE WILL BE A CHANCE FOR SHOWERS/STORMS WEDNESDAY OVER PORTIONS
OF THE NORTHLAND...SHIFTING TO MAINLY EASTERN AREAS BY AFTERNOON.
THE CHANCE WILL BE HIGHEST OVER NORTHWEST WISCONSIN WHICH WILL BE
MOST IMPACTED BY THE SHORTWAVE. HIGHS AGAIN WILL BE IN THE 80S
WITH INCREASING DEWPOINTS OVER NORTHEAST MINNESOTA.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 AM CDT TUE SEP 1 2015

THE HOT AND HUMID WEATHER CONTINUES THROUGH THE REST OF THE WORK
WEEK. PRECIPITATION CHANCES ARE HIGHEST OVER THE WEEKEND WHEN A COLD
FRONT IS EXPECTED TO MOVE THROUGH...BUT A LARGE SPREAD IN MODEL
GUIDANCE REMAINS IN TERMS OF THE PLACEMENT OF PRECIPITATION AND
FRONTAL TIMING. WHILE THERE REMAINS UNCERTAINTY...MODELS ARE
BEGINNING TO TREND FARTHER NORTHWEST WITH PLACEMENT OF THE HEAVIEST
PRECIP OVER THE WEEKEND...BUT STILL LOOKS LIKE THERE WILL BE A GOOD
CHANCE FOR STORMS WHEN THE FRONT EVENTUALLY ROLLS THROUGH.

ON THE SYNOPTIC SCALE LITTLE HAS CHANGED IN TERMS OF THE OVERALL
PATTERN. STILL EXPECTING A LONGWAVE TROUGH TO DEEPEN OVER THE WEST
COAST WHILE A WEAK RIDGE BUILDS IN THE EAST. SOUTHWESTERLY FLOW OVER
THE UPPER MIDWEST WILL KEEP US IN THE TRACK OF MID-LEVEL SHORTWAVE
TROUGHS THAT MOVE ACROSS THE FLOW. LATE IN THE WEEKEND INTO EARLY
NEXT WEEK SOLUTIONS DIVERGE WITH GFS/ECMWF/GEM DEPICTING A WIDE
RANGE IN TERMS OF TIMING AND AMPLITUDE OF HOW THE LONGWAVE TROUGH IN
THE WEST EVOLVES...WITH THE DIFFERENCES BETWEEN MODELS ONLY
INCREASING INTO THE WORK WEEK NEXT WEEK.

EVEN WITH THE VARIATION IN GUIDANCE THE BASICS OF THE LATE WEEK TO
WEEKEND PATTERN HAS NOT CHANGED...WE WILL STILL BE WITHIN THE WARM
SECTOR WITH DEW POINTS AS HIGH AS THE LOW 70S WITH WARM AIR ALOFT
CAPPING THE ENVIRONMENT FOR THURSDAY. ON FRIDAY A MID-LEVEL WAVE
COMBINED WITH DIURNAL HEATING SHOULD PROVIDE JUST ENOUGH LIFT FOR
ISOLATED TO SCATTERED STORMS...THOUGH VERY WEAK WINDS ALOFT AND VERY
HIGH LFC WILL RESULT IN ISOLATED SHORT-LIVED AND SLOW-MOVING STORMS
IF STORMS DO MANAGE TO DEVELOP. FOR SATURDAY A FAIRLY STRONG COLD
FRONT WILL BEGIN TO APPROACH...BUT IF TRENDS CONTINUE IT LOOKS
SIMILAR TO FRIDAY WITH THE VERY WARM AIR MASS PREVENTING WIDESPREAD
CONVECTION...BUT STILL A RISK FOR ISOLATED TO SCATTERED CONVECTION
DEPENDING ON THE EVOLUTION OF WEAK MID-LEVEL WAVES IN THE SOUTHWEST
FLOW ACROSS THE PLAINS. SATURDAY STORMS HAVE THE POTENTIAL TO BE
MORE ORGANIZED DUE TO STRONGER WINDS ALOFT...BUT THE WARM AIR AT
UPPER LEVELS /ABOVE 500MB/ MAY RESULT IN LESSER INSTABILITY FOR
SATURDAY. SUNDAY IT LOOKS LIKE THE FRONT WILL COME THROUGH IT SEEMS
THE STRONGEST FORCING MAY BE IN SOUTHERN MANITOBA/NORTHWEST ONTARIO.
SHOWERS AND STORMS LIKELY BUT HARD TO PUT IT MORE DETAIL THIS DUE TO
VARIATIONS IN TIMING.

THE POSSIBILITY FOR HEAVY PRECIPITATION STILL SEEMS PLAUSIBLE PER
ENSEMBLE SUPPORT...BUT AGAIN THERE HAS DEFINITELY BEEN A TREND WITH
MODELS SHIFTING THE BETTER FORCING FARTHER NORTHWEST. STILL...BOTH
GEFS AND ECMWF EPS ENSEMBLE MEMBERS SUPPORT THE POTENTIAL FOR 1-2
INCHES ACROSS THE REGION OVER THE WEEKEND INTO EARLY NEXT WEEK. THE
CHANCES ARE BETTER FOR HIGHER AMOUNTS NORTH AND WEST...BUT ALL OF
THE NORTHLAND IS WITHIN THE MARGIN OF ERROR AT THIS POINT FOR THE
POTENTIAL FOR HEAVY RAIN THIS WEEKEND.

SEVERE WEATHER POTENTIAL...COULD SEE A FEW STRONG STORMS FRI/SAT/SUN
BUT AT THIS POINT THE SIGNALS FOR SEVERE THUNDERSTORMS ARE NOT
PARTICULARLY STRONG EACH DAY.

EARLY NEXT WEEK THE FORECAST IS SIMPLER AS MUCH COOLER AIR MOVES
INTO THE NORTHERN PLAINS AND UPPER MIDWEST RESULTING IN A RETURN TO
MORE SEASONABLE TEMPERATURES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 645 AM CDT TUE SEP 1 2015

ANOTHER MORNING OF LIFR/IFR CEILINGS AND VISIBILITY QUICKLY
IMPROVING TO VFR BY MID-MORNING...REMAINING VFR THROUGH THE DAY.
WINDS WILL BE OUT OF THE WEST AND LIGHT TODAY...EXCEPT FOR AT BRD
WHERE A WEAK HIGH IN THE VICINITY WILL CAUSE LIGHT AND VARIABLE
WINDS. TONIGHT EXPECT ISOLATED SHOWERS AROUND BRD AND HYR...WITH
FOG ALSO POSSIBLE AT EITHER SITE TOWARDS SUNRISE. OTHERWISE VFR AT
OTHER TAF SITES.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  82  65  81  63 /  20  20  20  20
INL  82  55  85  64 /  10  20  20  10
BRD  83  65  84  68 /  10  20  10  10
HYR  81  64  85  63 /  20  20  30  30
ASX  83  62  83  60 /  20  10  20  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&

$$

SHORT TERM...MELDE
LONG TERM...JJM
AVIATION...JJM



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