Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 031408 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
908 AM CDT THU SEP 3 2015

.UPDATE...
ISSUED AT 904 AM CDT THU SEP 3 2015

EXTENDED THE DENSE FOG ADVISORY UNTIL NOON TODAY AS THE DENSE FOG
PERSISTS ACROSS AREAS ADJACENT TO LAKE SUPERIOR. COULD LIKELY SEE
THE LOW CLOUDS AND FOG LINGER AROUND THE LAKE THROUGH THE
AFTERNOON...BUT THE REDUCED VISIBILITIES SHOULD IMPROVE BY NOON.
CANCELLED THE ADVISORY FOR IRON COUNTY AS CONDITIONS ARE ALREADY
IMPROVING FROM EAST TO WEST. A PERSISTENT EAST WIND OFF THE LAKE
WILL KEEP CONDITIONS COOL. HAVE LOWERED HIGHS TODAY A FEW DEGREES
AROUND THE IMMEDIATE LAKE SHORE AREAS.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 343 AM CDT THU SEP 3 2015

AN AMPLIFYING UPPER LEVEL RIDGE OVER THE NORTHERN PLAINS AND
SURFACE HIGH PRESSURE OVER ONTARIO HAVE HELPED TO CREATE THE
CONDITIONS CONDUCIVE FOR LOW STRATUS AND FOG ACROSS THE NORTHLAND
EARLY THIS MORNING. THE RIDGE HELPED KEEP THE REGION CLEAR OF
CLOUD COVER GOING INTO THE EVENING...WHICH PROMOTED RADIATIONAL
COOLING. THE WINDS BECAME LIGHT OVERNIGHT...AND EASTERLY FLOW
USHERED IN MORE HUMID AREA FROM THE LAKE SUPERIOR REGION.
WIDESPREAD BKN/OVC STRATUS HAS BEEN PUSHING INLAND THROUGH THE
NIGHT AND EARLY MORNING...AND THE STRATUS IS LOW ENOUGH IN SOME
LOCATIONS TO CAUSE DENSE FOG. THE HIGH RESOLUTION MODELS AND
OBSERVATIONS SUGGEST THE DENSEST FOG CAN BE EXPECTED TO CONTINUE
FOR AREAS CLOSER TO LAKE SUPERIOR...CLOSER TO THE MAIN SOURCE OF
HUMID AIR. ISSUED A DENSE FOG ADVISORY FOR THOSE AREAS UNTIL 9 AM.
WHILE THE STRATUS AND FOG SHOULD GRADUALLY LIFT AND DISSIPATE WITH
THE RISING SUN...IT MAY LINGER UNTIL LATER IN THE MORNING FOR
AREAS CLOSE TO SUPERIOR.

EAST TO SE FLOW WILL CONTINUE THROUGH THE REST OF THE DAY AS THE
UPPER LEVEL RIDGE AMPLIFIES AND MOVES OVER THE NORTHLAND. MOST
AREAS SHOULD SEE SUNNY SKIES DEVELOP THIS AFTERNOON...BUT THERE
COULD BE LINGERING CLOUD COVER FROM THE TWIN PORTS AND ALONG THE
SOUTH SHORE BECAUSE OF THE COOLER AND MORE HUMID NE FLOW FROM LAKE
SUPERIOR. HIGH TEMPERATURES SHOULD RANGE FROM THE UPPER 60S AND
LOWER 70S NEAR LAKE SUPERIOR...TO THE UPPER 70S AND LOW 80S
INLAND.

CLEAR SKIES AND LIGHT WINDS TONIGHT WILL LIKELY RESULT IN MORE LOW
STRATUS AND SOME FOG. OVERNIGHT LOWS SHOULD RANGE FROM THE 50S
NEAR LAKE SUPERIOR...TO THE LOWER 60S INLAND.

FRIDAY SHOULD BE A BIT WARMER AS MORE SOUTHERLY FLOW DEVELOPS
AHEAD OF LOW PRESSURE IN THE PLAINS. THERE WILL BE INCREASING
CLOUD COVER FROM THE WEST LATER IN THE DAY RELATED TO CONVECTION
IN THE PLAINS AND SHORTWAVES LIFTING THROUGH THE REGION. EAST TO
NE FLOW FROM LAKE SUPERIOR WILL LIMIT AREAS NEAR THE LAKE TO THE
70S...BUT LOW TO MIDDLE 80S ARE LIKELY FOR AREAS INLAND.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM CDT THU SEP 3 2015

REMAINING HOT AND HUMID THROUGH THE WEEKEND WITH NUMEROUS CHANCES
FOR SHOWERS AND STORMS...SOME STRONG...ENDING ON SUNDAY/SUNDAY
NIGHT AS A STRONG COLD FRONT MOVES EAST ACROSS THE REGION. FOR THE
WORK WEEK NEXT WEEK TEMPERATURES DIVE TO NEAR/BELOW NORMAL AN AREA
OF HIGH PRESSURE BUILDS ACROSS THE NORTHERN PLAINS/UPPER
MISSISSIPPI VALLEY WITH COOL AIR ADVECTING IN AT LOW/MID LEVELS
FOLLOWING THE STRONG COLD FRONT. THIS LOOKS TO BE THE FIRST TIME
WE SEE THE 850MB 0C LINE FLIRTING WITH NORTHERN MINNESOTA SINCE
LAST SPRING. /A BRIEF INVESTIGATION OF INL SOUNDINGS REVEALS THE
LAST TIME THE 850MB TEMP AT INL FELL TO 0C OR COLDER WAS 00Z MAY
31...THAT NIGHT THE LOW WAS 30./ NOT LOOKING LIKE RECORD BREAKING
COLD AIR...BUT STILL APPROACHING THE BOTTOM TENTH PERCENTILE OF
CLIMATOLOGY.

THIS WEEKEND...STARTING TO GET A BETTER HANDLE ON THE UPPER LEVEL
PATTERN BUT SOME UNCERTAINTY REMAINS WITH REGARDS TO
TIMING...PLACEMENT...AND INTENSITY ESPECIALLY ON SAT NIGHT THROUGH
SUN NIGHT. ON THE BROAD SCALE WE HAVE A DEEP LONGWAVE TROUGH OVER
THE WEST COAST WITH A RIDGE OVER THE EAST...CENTERED OVER THE
EASTERN GREAT LAKES ON FRIDAY NIGHT. WITH SOUTHWESTERLY FLOW ALOFT
OVER THE UPPER MIDWEST A MID-LEVEL SHORTWAVE TROUGH WILL BE
TRAVERSING OVER THE REGION FRIDAY NIGHT BRINGING A WIDESPREAD
CHANCE FOR STORMS. SHOULD SEE A BREAK IN THE ACTION ON SATURDAY
AFTERNOON DUE TO SOME WEAK MID-LEVEL RIDGING FOLLOWING THE FIRST
SHORTWAVE TROUGH. THIS BREAK WILL NOT LAST LONG AS YET ALONG MID-
LEVEL IMPULSE ARRIVES FOR SATURDAY NIGHT INTO SUNDAY. LATE SUNDAY
INTO SUNDAY NIGHT A COLD FRONT WILL MOVE THROUGH ASSOCIATED WITH
AN UPPER LOW/SFC LOW OVER THE NORTHERN PLAINS INTO SOUTHERN
MANITOBA.

SEVERE WEATHER CHANCES DO NOT LOOK GREAT THROUGH THE WEEKEND.
WHILE EARLY ON THERE WERE HINTS THIS COULD BE A BIG RAIN
MAKER...AS MODEL SOLUTIONS HAVE TRENDED THIS THREAT WILL BE BEST
IN SOUTHERN CANADA. THE FIRST ROUND FRIDAY NIGHT INTO EARLY SUNDAY
WILL BE WEAK SHEAR/LOW CAPE LEADING TO SCATTERED STORMS THAT AT
LEAST AT THIS POINT DO NOT APPEAR TO BE CAPABLE OF REACHING SEVERE
CRITERIA. THE SECOND ROUND SAT NIGHT INTO SUNDAY SHOWS SIGNS OF
SOMEWHAT BETTER INSTABILITY DEPENDING ON DIURNAL HEATING ON
SATURDAY AFTERNOON IF POSSIBLE...AND AT LEAST MODESTLY STRONGER
WINDS ALOFT TO AID IN ORGANIZATION. SUNDAY NIGHT AHEAD OF THE COLD
FRONT THERE COULD BE A WINDOW FOR STRONG TO SEVERE STORMS DUE TO
IMPROVED MID-LEVEL LAPSE RATES AND MUCH STRONGER WINDS ALOFT
LEADING TO DEEP LAYER SHEAR OF 25-30 KTS...NOT GREAT BUT CERTAINLY
CAPABLE OF PRODUCING MULTICELLULAR STRONG TO SEVERE STORMS CAPABLE
OF DAMAGING WINDS AND LARGE HAIL AT TIMES GIVEN MUCAPE IN EXCESS
OF 2000 J/KG. BEST TIMING FOR HEAVY RAIN LOOKS TO BE SATURDAY INTO
SATURDAY NIGHT GIVEN PWATS AND SLOWER STORM MOTION.

OTHERWISE THIS WEEKEND...HOT AND MUGGY WITH HIGHS IN THE LOW 80S
AND DEW POINTS IN THE LOW 70S...PRETTY STICKY FOR EARLY SEPTEMBER.
BREEZY WINDS OUT OF THE SOUTH.

MONDAY THROUGH WEDNESDAY...COOLER WITH CLOUDS AND OCCASIONAL
CHANCES FOR SHOWERS. BREEZY WEST TO SOUTHWEST WINDS ON MONDAY
AFTERNOON FOLLOWING THE COLD FRONT. SHOULD SKIES CLEAR OUT
OVERNIGHT LOWS COULD FALL TO THE UPPER 30S ACROSS NORTHERN
MINNESOTA TUES/WED NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 636 AM CDT THU SEP 3 2015

LIFR TO IFR CONDITIONS WILL PREVAIL THROUGH MID-MORNING. UTILIZED
CLIMATOLOGY TOOL TO AIDE IN TIMING WHEN CONDITIONS WILL
IMPROVE. AT ALL SITES SHOULD SEE IMPROVEMENT TO VFR BY THE EARLY
AFTERNOON...THOUGH IT IS POSSIBLE CEILINGS REMAIN MVFR AT DLH AND
POSSIBLY HYR THROUGH THE AFTERNOON. WINDS LIGHT THIS MORNING BUT
BECOMING GUSTY OUT OF THE SOUTHWEST DURING THE DAY WITH GUSTS UP
TO 15-18 KTS POSSIBLE. TONIGHT ANOTHER ROUND OF IFR
CEILINGS/VISIBILITY POSSIBLE AT ALL TAF SITES...BUT CONFIDENCE IS
GREATEST AT DLH AND HYR WHERE VISIBILITY REDUCTIONS TO IFR OR
WORSE POSSIBLE AFTER MIDNIGHT.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  66  59  77  63 /  10   0   0  30
INL  84  63  85  66 /   0   0  10  60
BRD  84  67  85  69 /   0   0  10  50
HYR  80  64  84  66 /   0   0   0  20
ASX  73  57  80  62 /   0   0   0  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL NOON CDT TODAY FOR WIZ001>003.

MN...DENSE FOG ADVISORY UNTIL NOON CDT TODAY FOR MNZ020-037.

LS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LSZ121-
     142>148.

&&

$$

UPDATE...TENTINGER
SHORT TERM...GROCHOCINSKI
LONG TERM...JJM
AVIATION...JJM



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