Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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865
FXUS63 KDTX 102038
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
338 PM EST WED FEB 10 2016

.DISCUSSION...

AN UPPER LEVEL SHORT WAVE TROUGH WORKING ACROSS THE GREAT LAKES THIS
EARLY THIS AFTERNOON IS PROVIDING SOME SUPPORT FOR THE DECENT LAKE
EFFECT SETUP ACROSS THE REGION. CYCLONIC FLOW...STRONG LOW LEVEL
LAPSE RATES WITH INCREASINGLY COLDER AIR ALOFT...OVER THE ICE FREE
LAKES RESULTED IN A GOOD COVERAGE OF SNOW SHOWERS THROUGH THE
AFTERNOON. AS THE TROUGH AXIS BEGAN TO EXIT TO THE EAST AND MIXING
CREATED MORE CELLULAR STRUCTURE BREAKING UP THE LAKE BANDS...A
MARKED DECREASE IN ACTIVITY HAS BEEN NOTED ACROSS THE AREA. THROUGH
THE REST OF THE EVENING...A LAKE AGGREGATE TROUGH DRAPED ACROSS
NORTHERN LOWER WILL RELEASE AND DROP SOUTHWARD THROUGH LOWER MI.
THIS WILL UTILIZE AND FOCUS ANY RESIDUAL MOISTURE RESULTING IN ONE
LAST CHANCE FOR SNOW SHOWERS THIS EVENING THROUGH ABOUT 04-06Z.
THEN...SUBSIDENCE AND DRIER AIR JUST WEST OF LAKE MI WILL SLIDE IN
OVERNIGHT PROVIDING A PERIOD OF CLEARING SKIES. DEGREE OF CLEARING
AND HOW FAST SKIES TRY TO CLEAR WILL HAVE A LARGE INFLUENCE ON LOW
TEMPS TONIGHT WITH A FRESH 6-12 INCHES OF SNOW OVER MUCH OF THE
THUMB WHERE TEMPS CAN TANK EASILY. SHOULD SEE IN THE SINGLE DIGITS
FOR MOST LOCATIONS NORTH OF ABOUT M59. NOT MUCH BETTER ACROSS THE
SOUTH AROUND 10 DEGREES.

FLOW WILL TURN MORE WESTERLY ON THURSDAY WHICH WILL KEEP SOME
MOISTURE ADVECTION ACROSS LOWER MI. AS COLDER AIR FILTERS INTO THE
REGION...ENHANCED LOW LEVEL LAPSE RATES UP TO 5000FT WILL CENTER THE
THIN LAYER OF MOISTURE NEAR THE DGZ WHICH SHOULD SUPPORT AT LEAST
FLURRIES THROUGH THE DAY.  THERE IS A LOW CHANCE WE COULD SEE MORE
SHOWERY ACTIVITY BUT RIGHT NOW CONDITIONS SEEM TO FAVOR FLURRIES. A
QUICK MOVING SYSTEM WILL THEN SKIRT THROUGH LOWER MI ON FRIDAY
PROVIDING SUPPORT FOR ANOTHER SHOT AT LIGHT SNOW
ACCUMULATIONS...THOUGH ONLY EXPECTING AROUND A HALF INCH.

MAIN STORY HEADING INTO THE END OF THE WEEK WILL BE THE COLD
ARCTIC AIR. 850MB TEMPS AROUND -15C TODAY WILL FALL TO NEAR
-20C TONIGHT AS THE ARCTIC AIR BEGINS TO SETTLES OVER THE REGION.
THE COLDEST AIR IS STILL WELL TO THE NORTH THUS TEMPS SHOULD REMAIN
AROUND 20 FOR HIGHS AND 10 FOR LOWS. THIS CHANGES FRIDAY NIGHT AS
THE NEXT DOMINATE UPPER LEVEL LOW DROPS OVER HUDSON BAY...SENDING AN
ARCTIC FRONT THROUGH THE GREAT LAKES. LOWS FRIDAY NIGHT SHOULD DROP
TO AROUND 0 DEGREES WITH GOOD CHANCE OF MANY LOCATIONS REACHING
NEGATIVE VALUES.

FRIGID TEMPS CONTINUE FOR THE WEEKEND AS THE ARCTIC UPPER LOW
PIVOTS THROUGH SOUTHEASTERN CANADA. MODELS CONTINUE TO BE LOCKED IN
WITH SHIFTING THE COLDEST PART OF THE AIRMASS /850 MB TEMPS AOB
-30C/ TO OUR EAST...BUT STILL LEAVING SE MI IN THE -25C RANGE. WITH
GUIDANCE INDICATING HIGHS 5 TO 15F AND 5-10KTS OF NW FLOW...WILL
STILL BE DEALING WITH SOME FRIGID WINDCHILLS. THIS COLD NW FLOW
NORMALLY FAVORS DRY WEATHER...BUT HAVE TO WATCH FOR THE POTENTIAL OF
A SUPERIOR-MICHIGAN LES BAND EXTENDING INTO SE MI. CONFIDENCE LOW IN
THIS POTENTIAL SO HAVE LEFT POPS OUT. AT NIGHT...SURFACE HIGH BUILDS
IN WHICH SHOULD RESULT IN SOME GOOD RADIATIVE COOLING POTENTIAL.
LOWERED MINS A FEW DEGREES FROM SUPERBLEND...EXPECTING THE MAJORITY
OF SE MI TO DROP BELOW ZERO. THIS COLD PUNCH DOES APPEAR TO BE SHORT-
LIVED HOWEVER...AS MIDLEVEL WAA COMMENCES LATE SUNDAY...AND HIGHS
RETURN TO NEAR 30 BY MONDAY.

&&

.MARINE...

LOW PRESSURE OVER LAKE ONTARIO DURING THE MORNING WILL CONTINUE TO
MOVE INTO THE NEW ENGLAND STATES TODAY. THIS WILL LEAVE STRONG NW
WIND OVER ALL MARINE AREAS TODAY THROUGH TONIGHT. A GALE WARNING
REMAINS IN EFFECT TONIGHT FOR THE OPEN WATERS OF CENTRAL AND
SOUTHERN LAKE HURON. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE
NEARSHORE WATERS OF SOUTHERN LAKE HURON THROUGH THURSDAY DUE TO THE
RESULTING HIGH WAVE ACTION AND WIND GUSTS AROUND 30 KNOTS. FREEZING
SPRAY REMAINS A CONCERN AS ARCTIC AIR SURGES SOUTHWARD OVER THE
REGION TODAY THROUGH TONIGHT. A WARNING FOR HEAVY FREEZING SPRAY IS
IN EFFECT TONIGHT WHEN THE BEST COMBINATION OF FREQUENT GALE FORCE
WIND GUSTS AND COLD AIR OCCURS.

ALL OF THESE HARSH MARINE CONDITIONS WILL EASE GRADUALLY DURING
THURSDAY AS THE WIND BACKS AND DECREASES BY LATE IN THE DAY...BUT
THE BREAK WILL BE SHORT LIVED AS ANOTHER ARCTIC FRONT APPROACHES
THURSDAY NIGHT INTO FRIDAY. THE COLDEST AIR OF THE SEASON WILL BRUSH
LAKE HURON AND LOWER MICHIGAN BEHIND THIS FRONT FOR THE WEEKEND.

&&

.AVIATION...ISSUED 1243 PM EST WED FEB 10 2016

PERSISTENT CYCLONIC FLOW COMBINED WITH WEAK STABILITY IN THE LOWER
TROPOSPHERE WILL MAINTAIN THE CHANCES FOR BANDED SNOW SHOWER
STRUCTURES THROUGH THE AFTERNOON HOURS. SHORTWAVE ENERGY ALOFT AND
AGGREGATE SURFACE TROUGH WILL ALSO BE IN THE PROCESS OF EJECTING
THROUGH SOUTHEASTERN MICHIGAN WHICH WILL PROVIDE ADDITIONAL SUPPORT.
MODEL DATA SUGGESTS LOCALIZED INCREASES IN LOW LEVEL CONVERGENCE FOR
AREAS SOUTH OF INTERSTATE I 69 DURING THE 20-02Z TIMEFRAME.
STAGGERED A TEMPO IFR VSBY MENTION FROM NORTH TO SOUTH. INCREASING
COLD AND DRY AIR ADVECTION TONIGHT BRINGS HIGHER POTENTIAL FOR
CLOUDS TO SCATTER OUT OVERNIGHT...BEFORE FILLING BACK IN THURSDAY
MORNING WITH AN INCREASING DIURNAL HEATING CONTRIBUTION.

FOR DTW... WEST TO NORTHWEST WIND WILL CONTINUE TO GUST MOSTLY AT 20
KNOTS OR LESS AND STAY UNDER CROSS WIND THRESHOLD. BANDED TO
OCCASIONAL CELLULAR SNOW SHOWERS SHOULD INCREASE AGAIN THIS
AFTERNOON WITH INCREASED DIURNAL SUPPORT. THERE IS INCREASING
POTENTIAL THAT AN ENHANCED POCKET OF CONVERGENCE ALONG WITH THE
RESIDUAL LAKE AGGREGATE SURFACE TROUGH WILL PUSH FROM NORTHWEST TO
SOUTHEAST THROUGH THE DETROIT METRO AREA DURING THE EVENING
COMMUTE/EARLY EVENING HOURS. WILL MONITOR TRENDS...BUT THERE IS
A GOOD SIGNAL THAT IFR VSBY RESTRICTIONS OF 1SM WILL BE POSSIBLE
AT DTW BETWEEN 23-02Z.

//DTW THRESHOLD PROBABILITIES...

* HIGH FOR CEILING AOB 5KFT TODAY AND TONIGHT.

* HIGH FOR SNOW AS PRECIPITATION TYPE.

* LOW FOR EXCEEDING WESTERLY CROSSWIND THRESHOLD TODAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
     THURSDAY FOR LHZ362-363-462>464.

     GALE WARNING UNTIL 4 AM EST THURSDAY FOR LHZ363-462-463.

     SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR LHZ441>443.

     GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LHZ362.

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

$$

DISCUSSION...DRK/DT
MARINE.......CB
AVIATION.....CB


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