199
FXUS63 KDLH 271122
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
622 AM CDT TUE OCT 27 2020
DISCUSSION
(TODAY THROUGH TUESDAY)
ISSUED AT 349 AM CDT TUE OCT 27 2020
CLEAR SKIES AND A COLD AIR MASS STILL IN PLACE OVER THE NORTHLAND
THIS MORNING WILL HAVE THE DAY STARTING WITH WIND CHILL VALUES IN
THE SINGLE DIGITS. TODAY, PRESSURE GRADIENT WILL BEGIN TO STRENGTHEN
RESULTING IN GUSTY WINDS OUT OF THE SOUTHEAST. A LOW PRESSURE SYSTEM
WILL GLIDE ACROSS THE CANADIAN PRAIRIES TODAY WITH A BRANCH OF THE
WARM FRONT DRAPED THROUGH THE NORTHERN PLAINS. THE ISENTROPIC LIFT
ASSOCIATED WITH THE THE WARM AIR ADVECTION WILL INSTIGATE SOME SNOW
SHOWERS ACROSS THE BORDERLANDS HEADING INTO THE AFTERNOON AND
EVENING HOURS. LACK OF DEEP LEVEL MOISTURE AND WEAK LAPSE RATES WILL
RESULT IN LIGHT SNOW WITH NEGLIGIBLE ACCUMULATION TOTALS.
PRECIPITATION ACTIVITY IS EXPECTED TO WANE OVERNIGHT.
THE EXITING LOW PRESSURE ACROSS CANADA WILL HAVE IT'S COLD FRONT
SWEEP ACROSS THE BORDERLANDS EARLY WEDNESDAY. AMPLE MOISTURE ON THE
BACKSIDE OF THE LOW COMBINED WITH A STRONG VORT MAX WILL INCITE A
WINTRY MIX. LOSS OF ICE CRYSTALS WITHIN THE DENDRITIC GROWTH ZONE
COULD LEAD TO FREEZING RAIN IN THE MORNING. TEMPERATURES ARE
EXPECTED TO WARM THROUGH THE DAY AS THE COLD AIR MASS DEPARTS TO THE
EAST. PRECIPITATION WILL TRANSITION TO MOSTLY RAIN BEFORE NOON. THIS
LAST BATCH OF RAIN WILL TAPER OFF WEDNESDAY EVENING.
A SURFACE HIGH PRESSURE SETTING UP OVER CENTRAL CANADA WILL PROMOTE
SOME NORTHERLY WINDS ACROSS LAKE SUPERIOR. WE HAVE ADDED THE MENTION
OF SOME SNOW SHOWERS IN IRON AND ASHLAND COUNTIES FOR THURSDAY TO
ACCOUNT OF LAKE EFFECT SNOW/RAIN SHOWERS. ELSEWHERE, THE REGION WILL
STAY DRY THROUGH MOST OF THE FORECAST PERIOD. TEMPERATURES WILL
BEGIN TO REGULATE BACK TO NORMAL HIGHS FOR OCTOBER WITH SOME
POTENTIAL TO BE ABOVE AVERAGE (MID TO UPPER 40S) FOR HALLOWEEN.
THIS WEEKEND AN UPPER LEVEL TROUGH TRAVERSES ACROSS THE COUNTRY WITH
IT'S ASSOCIATED SURFACE LOW MOVING THROUGH CANADA. A FEW OF THE 00Z
SUITE OF MODEL GUIDANCE SUGGESTS SOME PRECIPITATION OVER THE
ARROWHEAD SATURDAY EVENING. THERE IS STILL A RATHER HIGH AMOUNT OF
MODEL DISAGREEMENT WITH THE QPF FIELD. FOR NOW, WE HAVE ADDED THE
MENTION OF A SLIGHT CHANCE.
AFTER THE TROUGH PASSAGE, AN UPPER LEVEL RIDGE BUILDS IN FROM THE
WEST. A SURGE OF WARM AIR AT 850MB WILL HELP TEMPERATURES CLIMB ONCE
AGAIN TO START THE WORK WEEK. SOME AREAS COULD EVEN BREAK BACK INTO
THE 50S BY TUESDAY.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 620 AM CDT TUE OCT 27 2020
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE MAJORITY OF TODAY. STRONG
SOUTHWESTERLY WINDS WILL STREAM ACROSS THE REGION WITH GUSTS UPWARDS
OF 25 KTS. AN APPROACHING WEATHER SYSTEM WILL GLIDE ACROSS THE
CANADIAN PRAIRIES GIVING WAY TO LIGHT SNOWFALL ACROSS NORTHERN MN. A
FEW BURSTS OF SNOWFALL COULD REDUCE VISIBILITY AT INL TO IFR OR
WORSE AT TIMES. OVERALL, SNOWFALL AMOUNTS ARE EXPECTED TO BE
NEGLIGIBLE WITH THIS SYSTEM. MVFR CEILINGS WILL FILTER IN ACROSS
NORTHERN MN BEHIND THE EXITING SYSTEM WITH SOME MODEL GUIDANCE
SUGGESTING IFR CEILINGS AT INL OVERNIGHT. ADDITIONALLY, EXPANDED
THE COVERAGE OF LOW LEVEL WIND SHEAR THIS EVENING TO ENCOMPASS
DLH/BRD/HYR.
MARINE
ISSUED AT 349 AM CDT TUE OCT 27 2020
INCREASING PRESSURE GRADIENT OVER LAKE SUPERIOR HAS RESULTED IN GUSTY
SOUTHWEST WINDS. A SMALL CRAFT ADVISORY IS CURRENTLY IN EFFECT AND
WILL BE UPGRADED TO A GALE WARNING AT 10 AM. IN ADDITION TO GALE-
FORCE WINDS, WAVES WILL BUILD TODAY. THE HIGHEST WAVES OF 8 TO 11
FEET ARE EXPECTED TO BE NORTHEAST OF GRAND MARAIS. ELSEWHERE, WAVES
ARE EXPECTED TO BE 4 TO 8 FEET. THE GALE WARNING IS SET TO EXPIRE
TOMORROW AT 4 AM. AT WHICH TIME A SMALL CRAFT ADVISORY WILL LIKELY
BE NEEDED FOR ALL NEAR SHORE WATERS. WINDS AND WAVES ARE EXPECTED TO
TAPER OFF WEDNESDAY AFTERNOON.
PRELIMINARY POINT TEMPS/POPS
DLH 30 26 43 25 / 0 10 10 10
INL 33 28 40 22 / 30 30 50 10
BRD 30 27 42 25 / 0 10 10 0
HYR 32 25 43 25 / 0 10 10 10
ASX 34 28 45 28 / 0 10 10 10
DLH WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LSZ121-
140>148.
GALE WARNING FROM 10 AM THIS MORNING TO 4 AM CDT WEDNESDAY FOR
LSZ121-140>148.
DISCUSSION...BRITT
AVIATION...BRITT
MARINE...BRITT
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