Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 030843
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
343 AM EST WED FEB 3 2016

.DISCUSSION...

THE CENTER OF THE STRONG LOW PRESSURE SYSTEM AT ISSUANCE TIME WAS
OVER SOUTHERN LAKE MICHIGAN AS IT CONTINUES TO STEADILY MOVE
NORTHEAST.  THIS LOW WILL FINALLY PUSH AWAY FROM THE GREAT LAKES
REGION LATER THIS AFTERNOON INTO THIS EVENING.  ONGOING WARMING
TREND...ESPECIALLY ACROSS SOUTHEAST PORTIONS OF THE CWA...ALLOWED
TEMPS TO RISE INTO THE LOWER 50S EARLY THIS MORNING.  JUST AS
QUICKLY AS WARMER AIR ARRIVED THE FIRST FRONTAL BOUNDARY WILL COME
IN ENDING THE TREND THIS MORNING.  TEMPS WILL STEADY OUT THROUGH THE
DAY BEFORE ANOTHER SHOT OF COOLER AIR ARRIVES THIS EVENING ON
NORTHWESTERLY FLOW.  LATEST OBS SHOW A MOISTURE RICH ENVIRONMENT
RESULTING IN THE DEVELOPMENT OF DENSE FOG OVER NORTHERN ILLINOIS AND
NORTHWEST INDIANA.  THIS FOG HAS BEEN SLOWLY CREEPING NORTHEAST INTO
FAR SOUTHWESTERN MICHIGAN.  CONDITIONS WILL CONTINUE TO BE MONITORED
TO SEE IF FOG CAN WORK INTO NORTHWESTERLY PARTS OF THE CWA BUT MAY
BE LIMITED DUE TO THE SOUTHERLY FLOW.

AS THE LOW PASSES OVER LOWER MICHIGAN...WINDS CALM DOWN FOR A BRIEF
PERIOD DURING THE MORNING HOURS BEFORE INCREASING AGAIN THIS
AFTERNOON INTO THE EVENING.  ONCE THE CENTER OF THE LOW TRACKS OFF
TO THE NORTHEAST...THE AREA WILL BE BACK INTO A TIGHTENING GRADIENT
AS THE BACKSIDE OF THE SYSTEM MOVES ACROSS TONIGHT. THIS WILL ALLOW
FOR WINDS TO ONCE AGAIN BECOME GUSTY. WINDS EVENTUALLY DIMINISH BY
THURSDAY MORNING AS THE GRADIENT WEAKENS. WRAP AROUND MOISTURE FROM
THE SYSTEM WILL CONTINUE TO KEEP CHANCES IN FOR SNOW SHOWERS THROUGH
THE OVERNIGHT HOURS AFTER A BREAK IN THE PRECIP THIS MORNING AND
AFTERNOON AS THE DRY SLOT TREKS THROUGH.

BY FRIDAY HEIGHTS BEGIN TO RISE AS SURFACE HIGH PRESSURE BUILDS BACK
IN.  THIS LEADS TO QUIETER CONDITIONS THROUGH AT LEAST THE BEGINNING
OF THE WEEKEND.  A WEAK WAVE THEN QUICKLY WORKS ACROSS NORTHERN
ONTARIO AND MAY BRING SOME SNOW SHOWERS TO EXTREME NORTHERN PARTS OF
THE CWA.  SOUTHEAST MICHIGAN WILL BE INBETWEEN WAVES ON SUNDAY
BEFORE A MORE PROMINENT LONGWAVE TROUGH DIGS SOUTH ON MONDAY
ALLOWING EVEN COOLER CANADIAN AIR TO FILTER IN.  THIS TROUGHING WILL
KNOCK TEMPS BACK DOWN TO NORMAL BY MIDWEEK.

&&

.MARINE...

SECONDARY SURFACE LOW DEVELOPMENT HAS TAKEN HOLD OVER SOUTHWEST
LOWER MICHIGAN EARLY THIS MORNING. THIS LOW WILL LIFT INTO NORTHERN
LAKE HURON BY LATE MORNING...WHILE THE SFC LOW NOW OVER IOWA WEAKENS
INTO MORE OR LESS A TROUGH AXIS. WINDS WILL DECREASE DURING THE
MORNING...FIRST AS WARM AIR PUSHES ACROSS THE LAKE AND REDUCES
MIXING DEPTHS AND THEN LATER IN THE MORNING AS THE GRADIENT RELAXES
WITH THE SFC LOW MOVING OVERHEAD. THIS LOW WILL LIFT NORTHEAST INTO
CANADA DURING THE AFTERNOON...CAUSING WINDS TO SHIFT TO THE
SOUTHWEST. COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM WILL BOOST
MIXING DEPTHS AS THE SW GRADIENT TIGHTENS. THIS WILL LEAD TO A BRIEF
PERIOD OF GALE FORCE WIND GUSTS IN THE 21Z TO 03Z TIME FRAME /MOST
LIKELY ACROSS SAGINAW BAY OUT INTO CENTRAL LAKE HURON/. THE WINDS
WILL VEER TOWARD THE WEST-NORTHWEST DURING THE NIGHT WHILE WEAKENING
AS THE LOW PRESSURE SYSTEM EXITS THE REGION. BROAD SFC TROUGHING
WILL PERSIST ACROSS THE NRN GREAT LAKES THROUGH THE END OF THE
WEEK...GENERALLY SUPPORTING LIGHT WEST-SOUTHWEST WINDS.

&&

.HYDROLOGY...

AFTER LAST EVENING/NIGHTS RAINFALL...DRIER CONDITIONS WILL PREVAIL
THROUGH THE REMAINDER OF THE WEEK. RADAR RAINFALL ESTIMATES SUGGESTS
THE HEAVIEST RAINFALL OCCURRED ACROSS THE SAGINAW VALLEY WITH
BETWEEN A HALF INCH AND A LITTLE OVER AN INCH. METRO DETROIT AND
POINTS SOUTH RECEIVED AROUND A HALF INCH WITH ANYWHERE FROM A TENTH
TO THREE TENTHS FALLING ACROSS THE REST OF THE FORECAST AREA.

&&

.AVIATION...ISSUED 1155 PM EST TUE FEB 2 2016

SCT SHRAS WITH ISOLATED THUNDER WILL CONTINUE OVER THE AREA INTO THE
FIRST SEVERAL HOURS OF THE FORECAST PERIOD AS A WARM FRONT LIFTS
INTO THE AREA...FOLLOWED CLOSELY BY THE PASSAGE OF A SURFACE TROUGH.
SSW FLOW ALONG THIS TROUGH WILL FUNNEL ADDITIONAL LOW LEVEL MOISTURE
INTO THE AREA WITH IFR CONDITIONS BECOMING MORE WIDESPREAD AS CIGS
DROP BELOW 1000 FEET AND VSBYS ALSO FALL TO 2-3SM...OR LESS...BY
LATE AT NIGHT INTO WEDNESDAY MORNING. CIGS SHOULD IMPROVE WITHIN
DRYING SW FLOW THROUGH MIDDAY WEDNESDAY WITH MOISTURE INCREASING
AGAIN LATER IN THE DAY AS UPPER TROUGH AXIS/COLD FRONT ENCROACH ON
THE AREA AND WINDS VEER TO THE WEST LATE IN THE FORECAST.

FOR DTW...PERIODIC RAIN WILL REMAIN POSSIBLE DURING THE FIRST
SEVERAL HOURS OF THE FORECAST...WITH IFR CIGS/VSBYS THEN FUNNELING
NNE INTO THE TERMINAL LATE AS WINDS VEER TO SSW AND AREA OF FOG OVER
ILLINOIS WORKS INTO SE MI.

//DTW THRESHOLD PROBABILITIES...

* HIGH FOR CIGS AT OR BELOW 5000 FT MUCH OF THE FORECAST.

* HIGH IN PRECIP TYPE BEING ALL RAIN TONIGHT.

* LOW CONFIDENCE IN THUNDERSTORMS DIRECTLY IMPACTING TERMINAL
  TONIGHT.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...GALE WARNING FROM 3 PM THIS AFTERNOON TO 10 PM EST THIS EVENING FOR
     LHZ362-363-421-462.

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

$$

DISCUSSION...SS
MARINE.......SC
HYDROLOGY....SC
AVIATION.....DG


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