Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 180439
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1139 PM CDT FRI OCT 17 2014

.UPDATE...
ISSUED AT 1137 PM CDT FRI OCT 17 2014
UPDATED TO ADD CHC RW- AROUND LAKE SUPERIOR AS GRVITY WAVE HAS
SHIFTED SLIGHT NORTH AND EXTENDED TO THE TWIN PORTS INTO NW WI.

.UPDATE...
MADE SOME ADJUSTMENTS TO THE TEMPS AND CLOUD COVER BASED ON
CURRENT TRENDS. ONE POSSIBLE PROBLEM IS A GRVITY WAVE ALONG THE
NORTH SHORE. IF THIS DRIFTS A LITTLE NORTH...THERE COULD BE SOME
LIGHT RAIN ALONG HIGHWAY 61. WILL KEEP PRECIP OUT FOR NOW AS IT
SEEMS THE WAVE IS DECREASING IN COVERAGE.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY AFTERNOON)
ISSUED AT 355 PM CDT FRI OCT 17 2014

MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE LINGERING
RAIN SHOWERS ACROSS THE ARROWHEAD SOUTHWARD THROUGH THE TWIN PORTS
INTO NW WI THIS AFTERNOON AND TONIGHT...WITH A LIGHT MIX OF
RAIN/SNOW POSSIBLE LATE THIS EVENING AROUND COOK/LAKE COUNTIES...AND
INTO THE GOGEBIC RANGE AND SWD AFTER MIDNIGHT. DRY CONDITIONS
EXPECTED MOST OF THE DAY SATURDAY.

UPPER LEVEL LOW CONTINUES TO TRACK EWD INTO THE GREAT LAKES THIS
AFTERNOON AND MERGE WITH A RETROGRADING LOW OVER ERN ONTARIO. AS
THESE TWO WAVES BECOME ONE TONIGHT THE ENTIRE SYSTEM WILL PICK UP
SPEED TO THE EAST AND LIFT OUT OF THE AREA AS HIGH PRESSURE BUILDS
IN FROM THE WEST. WEAK RIDGING ALOFT IS OCCURRING BEHIND THE
DEPARTING LOW MOVING INTO THE GREAT LAKES THIS AFTERNOON...WITH A
STRONGER SFC RIDGE EXTENDING FROM NRN MANITOBA INTO THE WRN PLAINS
EXPECTED TO BUILD EAST LATE TONIGHT AND EARLY SAT. THE AREAL
COVERAGE AND INTENSITY OF PRECIP THAT WAS SEEN EARLIER TODAY HAS
WEAKENED SUBSTANTIALLY DUE TO THE BROAD LARGE-SCALE SUBSIDENCE FROM
THE RIDGING ALOFT AND THE MAIN FORCING FROM THE LOW TRANSITIONING
FURTHER TO THE EAST. HOWEVER...A TRAILING WEAK S/W WILL RIDE SEWD
THROUGH THE WRN GREAT LAKES TONIGHT AND ALLOW THE LIGHT RAIN SHOWERS
TO PERSIST INTO EARLY SAT MORNING. THE AIR MASS ADVECTING IN FROM
THE NORTH WILL BE COLD ENOUGH TO CHANGE OVER OR MIX IN A LITTLE SNOW
LATE THIS EVENING AND TONIGHT. 925-850MB TEMPS TONIGHT WILL FALL TO
-1 TO -4 DEG C...WHICH WILL ALLOW CONDITIONS TO BECOME FAVORABLE FOR
SOME FREEZING PRECIP OVER THE TIP OF THE ARROWHEAD...AND INTO NRN
WI. THE PRECIP IN WI COULD BECOME ENHANCED FROM THE LAKE...AS A
FAVORABLE NRLY FLOW ACROSS THE LAKE WILL MODIFY THE BL AIR MASS
ENOUGH TO PRODUCE MODESTLY STEEP LOW LEVEL LAPSE RATES...WHICH WILL
COMBINE WITH DECENT BL MOISTURE TO TRIGGER ADDITIONAL LIGHT RAIN
SHOWERS ALONG THE SOUTH SHORE AND A MIX OF SNOW AT TIMES FURTHER
INLAND. ANY SNOW ACCUMULATION WILL BE VERY LIGHT AND LIKELY ONLY ON
GRASSY SURFACES OR VEHICLES.

A MUCH MORE ROBUST UPPER RIDGE BUILDS IN ACROSS THE UPPER MIDWEST
SAT MORNING AND INTO THE WRN GREAT LAKES THROUGH THE DAY. THIS RIDGE
WILL ALLOW CONDITIONS TO DRY OUT AND EVENTUALLY LEAVE ALMOST THE
ENTIRE REGION UNDER MOSTLY SUNNY SKIES. COULD TAKE SOME TIME BEFORE
THE MORNING STRATUS MIXES OUT DUE TO THE WARMING ALOFT AND COLD AIR
AT THE SFC KEEPING THE RESIDUAL MOISTURE TRAPPED IN THE BL...BUT
ONCE RELATIVELY DEEPER MIXING OCCURS IN THE LATE MORNING/EARLY
AFTERNOON THE REST OF THE DAY SHOULD BE NEARLY CLOUD FREE.

TEMPERATURES TONIGHT WILL FALL IN THE 20S ACROSS THE NORTH AND INTO
THE 30S TO THE SOUTH. AREAS THAT SEE MORE CLEARING WILL BE THE
COLDEST...WITH LOWER 20S NOT OUT OF THE QUESTION. ON
SATURDAY...TEMPS WILL WARM INTO THE LOWER TO MID 50S ACROSS THE WRN
COUNTIES...WITH UPPER 40S TO THE EAST. LIGHT WINDS EXPECTED SATURDAY
WITH THE SFC RIDGE AXIS DIRECTLY OVERHEAD.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 355 PM CDT FRI OCT 17 2014

THE SURFACE RIDGE SLIPS OFF TO OUR SOUTHEAST ON SATURDAY
NIGHT...JUST AS THE NEXT SHORTWAVE OVERTOPS THE RIDGE OVER
NORTHERN SASKATCHEWAN/MANITOBA. THIS WILL LEAVE US WITH SOUTH FLOW
AND MILDER TEMPERATURES OVERNIGHT...FALLING INTO THE 30S MOST
LOCATIONS.

THE SHORTWAVE MOVES ACROSS ONTARIO SUNDAY AND SUNDAY NIGHT...DRAGGING A
WEAK WARM FRONT ACROSS THE AREA DURING THE AFTERNOON AND EVENING.
THIS WILL BE ACCOMPANIED BY SOME RAIN SHOWERS...MAINLY ACROSS THE
ARROWHEAD AND NORTHWEST WISCONSIN.  TEMPERATURES WILL MAINLY BE IN
THE 50S...THOUGH THE TIP OF THE ARROWHEAD MAY ONLY GET INTO THE
UPPER 40S.  LOWS TO ONLY FALL INTO THE UPPER 30S TO LOW 40S WITH THE
EXTRA CLOUD COVER...DESPITE THE COLD FRONT TO MOVING THROUGH
OVERNIGHT.  PRECIPITATION CHANCES LINGER THROUGH MONDAY IN THE COLD
ADVECTION REGIME BEHIND THE SHORTWAVE.

WE SHOULD HAVE A NICE DAY ON TUESDAY WITH HIGHS IN THE 50S AS A
RIDGE OF HIGH PRESSURE MOVES ACROS THE AREA ALONG WITH RIDGING
ALOFT.  THE BROAD RIDGING ALOFT WILL BE INTERRUPTED BY A STRONG
SHORTWAVE THAT WILL RIPPLE THROUGH IT WEDNESDAY NIGHT AND
THURSDAY...BRINGING SOME SMALL CHANCES FOR PRECIPITATION.
OTHERWISE...THERE WILL BE A WARMING TREND THROUGH THE WEEK WITH
HIGHS BY FRIDAY IN THE UPPER 50S TO MID 60S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1244 PM CDT FRI OCT 17 2014

WIDESPREAD MVFR TO IFR CIGS ACROSS THE TERMINALS EXPECTED TO
CONTINUE THIS AFTERNOON WITH NORTHWEST CYCLONIC FLOW ENHANCES
STRATUS ACROSS THE AREA. SHOWERS STILL IN THE VICINITY OF SEVERAL
SITES...BUT ONLY KHYR LOOKS TO GET A PERIOD OF LIGHT RAIN THE NEXT
FEW HOURS. CLEARING SKIES TO VFR EXPECTED TO MOVE IN FROM THE NORTH
AFTER 04Z TONIGHT...GRADUALLY MOVING SOUTH TO AFFECT THE REMAINING
TERMINALS...WITH KHYR NOT GOING VFR UNTIL 13Z SATURDAY MORNING.
THIS IS BASED MAINLY ON MODEL GUIDANCE. EXTENSIVE CLOUD COVER
WELL UP INTO ONTARIO MAKES THE TIMING OF THE CLEARING SOMEWHAT LOW
CONFIDENCE...AND EXPECT TO BE MAKING ADJUSTMENTS IN THE COMING
HOURS. AT THE MOST PESSIMISTIC...CLEARING MAY NOT BE UNTIL 15-21Z
SATURDAY.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  33  46  37  54 /  30   0   0  20
INL  29  46  36  55 /  10   0  10  20
BRD  36  53  38  60 /  10   0   0  10
HYR  34  47  33  55 /  20   0   0  20
ASX  35  45  33  54 /  30   0   0  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT SATURDAY FOR LSZ121-146>148.

     SMALL CRAFT ADVISORY UNTIL 5 AM CDT SATURDAY FOR LSZ140.

&&

$$

UPDATE...STEWART
SHORT TERM...BJT
LONG TERM...LE
AVIATION...LE






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