Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 130831
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
331 AM EST SAT FEB 13 2016

.DISCUSSION...

WILL BE ALLOWING THE WIND ADVISORY FOR HURON COUNTY TO EXPIRE AS
WIND GUSTS ALONG THE LAKE HURON SHORELINE...ALREADY MARGINAL FOR AN
ADVISORY...WILL SLOWLY EDGE DOWN DURING THE REST OF THE MORNING.
WINDS WILL REMAIN ELEVATED ENOUGH TO MAINTAIN WIND CHILL READINGS OF
15 BELOW OR LESS AS TEMPERATURES EDGE BELOW ZERO EARLY THIS MORNING.
SLIGHTLY LIGHTER WINDS AND TEMPERATURES A FEW DEGREES MILDER WILL
REMAIN TO THE SOUTHWEST OF THE ADVISORY. EVEN SO...A CHILLY MORNING
CAN BE EXPECTED WITH WIND CHILLS HOVERING AROUND 10 BELOW ZERO EARLY
THIS MORNING.

IN ADDITION...SEVERAL NARROW LAKE EFFECT SNOW BANDS CONTINUE TO
STREAM INTO PARTS OF THE FORECAST AREA FROM MAIN LAKE SUPERIOR AND
NORTHERN LAKE MICHIGAN BANDING TO THE NORTH. THESE STREAMERS ARE
FORECAST TO REMAIN ACTIVE TO ONE DEGREE OR ANOTHER INTO THIS
AFTERNOON...FOCUSED GENERALLY FROM THE SAGINAW VALLEY SOUTHEAST INTO
PARTS OF NORTHERN METRO DETROIT. WOULD NOT BE TOO SURPRISED TO SEE A
SLIGHT SOUTHWEST DRIFT OF THE BANDING THIS MORNING AS TEMPERATURES
OVER NORTHERN LOWER MICHIGAN HAVE DROPPED WELL BELOW ZERO WITHIN
POCKET OF GENERALLY CLEAR SKIES. WITH TEMPERATURES OVER SOUTHEAST
MICHIGAN SOME 10F MILDER...THE MORE DENSE LOW LEVEL AIR TO THE NORTH
MAY TEND TO SEEP SOUTHWARD AND INFLUENCE THE POSITIONING OF THE MORE
PERSISTENT SNOW BANDS. WITH INVERSION HEIGHTS HOLDING IN THE 5000-
6000 FOOT RANGE INTO THE AFTERNOON...WOULD EXPECT SOME DECENT SNOW
SHOWERS AT TIMES. HOWEVER...OVERALL ACCUMULATIONS WILL BE GREATLY
LIMITED BY THE LACK OF AREAL COVERAGE OF THIS ACTIVITY. EXPECT NEW
ACCUMULATIONS OF LESS THAN AN INCH IN GENERAL WITH AN AMOUNTS OF AN
INCH OR MORE VERY LIMITED.

SURFACE RIDGING WILL BEGIN TO BUILD INTO THE AREA THIS EVENING INTO
THE OVERNIGHT. THE TEMPERATURE FORECAST WILL BE RATHER DIFFICULT AS
REMAINING LAKE EFFECT STREAMERS RE-ALIGN INTO THE THUMB REGION AS
THIS RIDGE ALLOWS FOR BACKING WINDS OVER SOUTHERN LOWER MICHIGAN.
WHILE THIS ACTIVITY WILL WANE TO FLURRIES DURING THIS TIME...PARTLY
TO MOSTLY CLOUDY SKIES IN SOME AREAS WILL REDUCE RADIATIONAL COOLING
SLIGHTLY AND KEEP TEMPERATURES CLOSER TO ZERO IN SOME AREAS. AT THE
SAME TIME...LOCATIONS THAT REMAIN LARGELY CLEAR MAY BOTTOM OUT
CLOSER TO 10 BELOW ZERO LATE TONIGHT AS WINDS BECOME LIGHT/VARIABLE
AS THE AFOREMENTIONED RIDGE SHIFTS OVER AREA BETWEEN 09Z-12Z. THIS
WILL BE MAINLY TRUE NORTH OF THE M-59 CORRIDOR...WHERE THE SNOWPACK
IS MORE EXTENSIVE. TEMPERATURES SOUTH OF THIS SHOULD HOLD NEAR ZERO
GIVEN LACK OF SIGNIFICANT SNOWPACK...WITH THE MILDEST POCKET WITHIN
THE RELATIVE URBAN HEAT ISLAND.

ONCE THE INTENSE UPPER LEVEL LOW PRESSURE SYSTEM OVER EASTERN CANADA
PROVIDING THIS COLD WEATHER SHIFTS INTO THE CANADIAN MARITIMES EARLY
NEXT WEEK...THE UPPER LEVEL FLOW WILL BECOME RATHER PROGRESSIVE FOR
THE REMAINDER OF THE FORECAST PERIOD. A PERIOD OF LIGHT SNOW STILL
LOOKS TO BE A GOOD BET OVERNIGHT SUNDAY NIGHT INTO EARLY MONDAY AS A
CLIPPER SYSTEM PIVOTS THROUGH THE CENTRAL AND SOUTHERN GREAT LAKES.
MODEL CONSENSUS ON THIS SYSTEM REMAINS RELATIVELY STEADY GIVEN THE
OVERALL DIFFICULTY IN HANDLING CLIPPERS. SNOW ACCUMULATIONS ON THE
ORDER OF AN INCH SEEMS REASONABLE.

LIKEWISE...THERE REMAINS A STRONG MODEL CONSENSUS OF DIGGING A
SHORTWAVE OF PACIFIC ORIGIN INTO THE CENTRAL/SOUTHERN MISSISSIPPI
VALLEY. ANY PHASING OF THIS SYSTEM WITH THE NORTHERN STREAM WOULD
THEN HOLD OFF UNTIL IT IS WELL SOUTHEAST OF LOWER MICHIGAN GIVEN THE
POSITION OF THE MEAN UPPER LEVEL TROUGH AXIS VERY NEAR THE AREA.

TEMPERATURES MODERATE CONSIDERABLY INTO MID/LATE NEXT WEEK AS THE
SUB TROPICAL JET BECOMES MORE DOMINANT OVER THE CONUS WITH A MORE
ZONAL...ALBEIT AMPLIFIED...UPPER LEVEL FLOW. WHILE THE SOUTHERN
STREAM IS NOT COMPLETELY SPLIT FROM THE NORTHERN STREAM...THE
INFLUENCE A PACIFIC AIRMASS EXPANDING EASTWARD ACROSS THE CONUS WILL
OUTWEIGH ANY SMALL INTRUSIONS OF POLAR AIR INTO THE NORTHERN CONUS.
HENCE...THE TEENS OVER THE WEEKEND WILL BE REPLACED BY UPPER 20S TO
MID 30S FOR HIGH TEMPERATURES MUCH OF THE WEEK WITH TEMPERATURES
CLIMBING BACK INTO THE 40S LATE IN THE FORECAST.

&&

.MARINE...

A GALE WARNING CONTINUES FOR SOUTH HALF OF LAKE HURON THIS MORNING
AS JUST ENOUGH THERMAL TROUGHING/GRADIENT PERSISTS. WINDS WILL
SUBSIDE BELOW GALE FORCE DURING THE AFTERNOON HOWEVER...AS HIGH
PRESSURE BUILDS INTO THE CENTRAL GREAT LAKES...BECOMING LIGHT
TONIGHT AS THE CENTER OF THE HIGH SETTLES OVER LOWER MICHIGAN. WHILE
WINDS WILL DECREASE...HIGH WAVES AND FRIGID TEMPERATURES WILL
CONTINUE THE THREAT FOR HEAVY FREEZING SPRAY THROUGH THIS EVENING
OVER THE SOUTHERN HALF OF THE LAKE. WINDS WILL SHIFT TO THE SOUTH
AND INCREASE ON SUNDAY AS THE HIGH EXITS EAST...BUT GENERALLY
TOPPING OUT AROUND 20 KNOTS....INTO MONDAY.

&&

.AVIATION...ISSUED 1201 AM EST SAT FEB 13 2016

GOOD SURGE OF ARCTIC AIR HAS BEEN EXHAUSTED THIS EVENING...AND
NORTHWEST WINDS SHOULD CONTINUE TO DIMINISHING AS NIGHT WEARS ON.
VERY NARROW SNOW BAND FROM LAKE SUPERIOR-LAKE MICHIGAN WILL BE
MEANDERING NEAR MBS-FNT-PTK THROUGH THE NIGHT INTO THE DAYTIME
HOURS...AND SHORT TERM ADJUSTMENTS MAY BE NEEDED TO ACCOUNT FOR
POTENTIAL MVFR/IFR SNOW SHOWER ACTIVITY. OTHERWISE...CLEAR-SCATTERED
SKIES EXPECTED DURING THE MORNING HOURS...WITH DIURNAL VFR CU THEN
EXPANDING DURING THE DAY...ALONG WITH ANOTHER MODEST PICKUP IN WINDS
WITH BETTER BOUNDARY LAYER MIXING...AS GUSTS REACHING AND SLIGHTLY
EXCEED 20 KNOTS. SURFACE HIGH PRESSURE BUILDING OVER SOUTHERN LOWER
MICHIGAN TONIGHT EXPECTED TO CLEAR US OUT ONCE AGAIN...WITH WINDS
BECOMING LIGHT/CALM.

FOR DTW...MOSTLY CLEAR SKIES EXPECTED THIS MORNING...BUT WILL STILL
HAVE TO KEEP CLOSE EYE ON THE VERY NARROW LAKE SNOW BAND WHICH
HAS EXTENDED INTO WESTERN OAKLAND COUNTY.

//DTW THRESHOLD PROBABILITIES...

* LOW CONFIDENCE IN CEILINGS AOB 5KFT THROUGH MORNING...MEDIUM THIS
  AFTERNOON...THEN LOW.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR MIZ049.

     WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR MIZ049-054-055-
     062-063.

LAKE HURON...HEAVY FREEZING SPRAY WARNING UNTIL 10 PM EST THIS EVENING FOR
     LHZ363-462>464.

     GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LHZ363-421-441>443-
     462>464.

     HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR
     LHZ421-441>443.

     HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
     LHZ361-362.

     GALE WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR LHZ361-362.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

DISCUSSION...SF
MARINE.......SF
AVIATION.....SF


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AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).


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