Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 201757
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1257 PM CDT WED AUG 20 2014

.UPDATE...
ISSUED AT 1257 PM CDT WED AUG 20 2014

NEW 18Z AVIATION DISCUSSION BELOW.

UPDATE ISSUED AT 543 AM CDT WED AUG 20 2014

DENSE FOG ADVISORY CANCELED FOR WISC COUNTIES AND NORTH SHORE AS
LOW STRATUS HAS INVADED SUFFICIENTLY ENOUGH TO LIMIT ADDITIONAL
COOLING OF BDRY LYR TEMPS. MORE FAVORED LOCATION HAS TRENDED NORTHWEST
SO ADDED KOOCH AND NRN ST LOUIS. IF LOW CLOUD CANOPY CONTINUES AT
THIS RATE MAY BE ABLE TO DROP MOST OF THE DFA AROUND 7AM.

&&

.SYNOPSIS...
ISSUED AT 322 AM CDT WED AUG 20 2014

VERTICALLY STACKED SFC/MID LVL LOW OVER U.P. OF MICH CONTINUES TO
PROVIDE A CYCLONIC CIRCULATION ALOFT OVER THE ERN CWA THIS
MORNING. MID LVL RIDGING IS BUILDING SLOWLY INTO THE WRN CWA AS
A BROAD UPSTREAM MID LVL TROF CONTINUES OVER THE NRN ROCKIES. A
LARGE ARE OF LOW STRATUS AND FOG...LOCALLY DENSE...HAS DEVELOPED
OVER MOST OF THE CWA. HAVE ISSUED A DFA FOR NOW OVER THE DULUTH TO
PINE COUNTY...NORTH SHORE..AND IRON RANGE VICINITY. HOWEVER...CONFIDENCE
IS LIMITED AS WE MAY SEE MORE LOW STRATUS THAN FOG. LATEST SHORT
TERM FCST OF SFC CPD SUGGESTS HIGHER PROB OF DENSE FOG WILL OCCUR
FROM I35 CORRIDOR TO KGPZ AND NORTH TO BORDER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT WED AUG 20 2014

TODAY...EARLY MORNING STRATUS AND FOG WILL GRADUALLY THIN/ERODE BY
MIDDAY MOST LOCATIONS AS BDRY LYR GRADUALLY WARMS AND ENTRAINMENT
ENHANCES EVAPORATION. MAIN MID LVL FEATURES MOVE VERY SLOWLY TODAY
SO SOME CONCERN THAT WE MAY HANG ONTO CLOUDS LONGER IN THE
EAST...AND A FEW MORE RW WILL DEVELOP THAN CURRENTLY FCST. HAVE
MAINTAINED LOW POPS IN ARROWHEAD FOR SOME RW TODAY ON BACK EDGE OF
CYCLONIC CIRCULATION FROM U.P SYSTEM. PREVAILING SE BDRY LYR FLOW
SHOULD KEEP NEAR LAKE LOCATIONS COOLER THAN WELL INLAND.

TONIGHT...A MID LVL TROF ACCOMPANIED BY A SFC LOW WILL MOVE INTO
WRN MN BY EARLY THURSDAY. WARM ADVECTION REGIME WILL STRENGTHEN QUICKLY
AFTER MIDNIGHT OVER THE WRN CWA. 85H MOISTURE TRANSPORT IS FCST TO
RAPIDLY INCREASE INTO SWRN CWA BY 12Z AS LLJ INTENSIFIES. A WARM
FRONT WILL ADVANCE INTO CTRL MN BY DAYBREAK WITH ISENTROPIC LIFT
OCCURRING NORTH OF THE BDRY INTO THE SRN CWA. HAVE INCREASED POPS
TO LIKELY ACROSS SWRN CWA...AND SRN TIER OF WRN WI ZONES. ELEVATED
CAPE COMBINES WITH SOME INCREASE IN DEEP LYR SHEAR TO PRESENT AN
OPPORTUNITY FOR A FEW STORMS WITH HAIL.

TOMORROW...WARM FRONT WILL ADVANCE INTO SRN EDGE OF CWA AS SFC
LOW TRACKS EAST..AND POSSIBLY REFORMS FARTHER SOUTHEAST OF CWA BY
LATE IN THE DAY. WILL NEED TO MONITOR POTENTIAL OF STRONG/SVR
STORMS AS INSTABILITY INCREASES SIGNIFICANTLY AS SUFFICIENT 0/6KM
SHEAR ADVECTS OVERHEAD. LATEST SREF FCST OF MLCAPES/EFFECTIVE
SHEAR SUGGEST SRN ZONES MAY BE AT RISK. ADDED FACTOR OF LOW LVL
BDRY MAY ENHANCE NEAR SFC CONVERGENCE AND LOW LVL HELICITY. HEAVY
RAIN WILL ACCOMPANY MAIN FORCING AREA AS IT SHIFTS NE INTO ERN CWA
DURING THE AFTN. FCST VALUES OF PWAT/WARM CLOUD DEPTH/LOW LVL JET
SUPPORT HIGH RAINFALL RATES WITHIN EMBEDDED CONVECTION. MAX TEMPS
IN WARM SECTOR NEAR LOWER ST CROIX VALLEY MAY REACH MID 80S.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 322 AM CDT WED AUG 20 2014

HE SURFACE LOW AND TROUGH AXIS THAT BEGAN TO PUSH ACROSS THE AREA
ON THURSDAY WILL CONTINUE NORTHEAST ACROSS THE AREA THURSDAY
NIGHT...WITH FAIRLY HIGH POPS NORTHEAST DURING THE EVENING...AND
THEN TAPERING OFF OVERNIGHT AS THE SYSTEM PUSHES FARTHER EAST.
TEMPERATURES TO FALL INTO THE MID 50S TO LOW 60S.

FRIDAY MORNING SOME SHOWERS TO CONTINUE FOR THE EAST...BUT THESE TO
COME TO AN END DURING THE DAY AND THE EVENING SHOULD BE DRY OR
NEARLY DRY...AS WE WILL BE IN THE WEAK RIDGING IN BETWEEN THE
EXITING FRONT AND THE NEXT WEATHER MAKER DEVELOPING OUT OVER THE
ROCKIES AND HIGH PLAINS.  CONDITIONS REMAIN MILD WITH THE UPPER
LEVEL RIDGE OVERHEAD...SO FRIDAY HIGHS IN THE 70S TO LOW 80S...AND
LOWS FRIDAY NIGHT TO ONCE AGAIN RANGE FROM THE MID 50S TO LOW 60S.

A STRONG UPPER LEVEL LOW WILL HAVE BEEN DEVELOPING OUT OVER THE
ROCKIES FRIDAY...AND WILL SWING OUT TOWARDS THE MIDWEST BEGINNING ON
SATURDAY.  CONVECTION FORMING ALONG A WARM FRONT DRAPED FROM SOUTH
DAKOTA ACROSS MINNESOTA AS EARLY AS FRIDAY NIGHT SHOULD AFFECT THE
SOUTHERN PORTIONS OF THE FORECAST AREA SATURDAY AND SATURDAY
NIGHT...THEN SWEEP ACROSS THE REST OF THE AREA ON SUNDAY AND SUNDAY
NIGHT AS THE UPPER LOW SWEEPS TOWARDS AND THEN ACROSS THE REGION.
MONDAY THE SYSTEM MOVES NORTHEAST OF THE AREA...WITH SOME LOWER
CHANCES FOR SHOWERS AND THUNDERSTORMS.  THOUGH WE HAVE SOME
UNCERTAINTY WITH TIMING AND TRACK...AM FAIRLY CONFIDENT IN A DECENT
RAINFALL EVENT FOR THE NORTHLAND THIS WEEKEND.  UNFORTUNATE FOR
VISITORS...BUT IT CANNOT BE HELPED.  TEMPERATURES TO REMAIN
SEASONABLE WITH HIGHS IN THE 70S SATURDAY AND SUNDAY...THEN COOLING
OFF INTO THE MID 60S TO LOW 70S MONDAY AND TUESDAY.  LOWS IN THE 50S
OVER THE WEEKEND WILL COOL OFF INTO THE MID 40S TO MID 50S FOR THE
EARLY PART OF NEXT WEEK AS WELL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1257 PM CDT WED AUG 20 2014

AN UPPER LOW LINGERED OVER WESTERN UPPER MICHIGAN EARLY THIS AFTERNOON...RESULTING
IN SHALLOW CLOUD DEVELOPMENT. EXPECT CEILINGS TO LIFT AND
COVERAGE TO DECREASE WITH ADDITIONAL HEATING THIS AFTERNOON. TERMINALS
SHOULD IMPROVE TO VFR CONDITIONS LATE THIS AFTERNOON CONTINUING
THROUGH LATE EVENING. WITH MOIST AIRMASS REMAINING IN PLACE ACROSS
THE REGION...CIGS AND VSBYS WILL DIMINISH AGAIN OVERNIGHT. A
SYSTEM WILL APPROACH FROM THE SOUTHWEST OVERNIGHT...BRINGING RAIN
SHOWERS AND THUNDERSTORMS INTO THE REGION THURSDAY MORNING...WITH
CONDITIONS IMPROVING AS THE RAIN MOVES IN.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  72  57  68  61 /   0  40  60  50
INL  77  56  71  58 /   0  20  60  50
BRD  80  62  82  62 /   0  70  70  20
HYR  75  59  80  64 /   0  50  60  40
ASX  72  54  75  62 /   0  20  60  60

&&

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

$$

SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...LE
AVIATION...HUYCK






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