Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 281710
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
110 PM EDT THU APR 28 2016

.AVIATION...

LOW PRESSURE SLIDING SOUTH OF THE OHIO BORDER DURING LATE AFTERNOON
AND EVENING WILL CONTINUE TO SUPPORT BROAD BANDS OF RAIN SHOWERS
MOST CONCENTRATED OVER MBS...FNT...AND PTK. THESE WILL TEND TO
WEAKEN DURING EARLY EVENING WHICH WILL ALLOW PERSISTENT NE LOW LEVEL
FLOW TO BE EVEN MORE EFFECTIVE AT HOLDING BACK MVFR CEILING ALONG
THE TERMINAL CORRIDOR THROUGH THE NIGHT. SURFACE WIND GENERALLY
ABOVE 5 KNOTS WILL ALSO KEEP FOG FROM BECOMING A PROBLEM AROUND
SUNRISE DESPITE WET GROUND LEFT OVER FROM SHOWERS TODAY. VFR WILL
THEN REMAIN IN PLACE THROUGH FRIDAY EVEN AS LOW PRESSURE OVER THE
MIDWEST MOVES IN WITH ANOTHER ROUND OF SHOWERS BY MID MORNING INTO
FRIDAY AFTERNOON.

FOR DTW... EAST TO NORTHEAST LOW LEVEL FLOW WILL BE THE PRIMARY
CHALLENGE FOR DTW OPERATIONS FORCING NE TRAFFIC FLOW INTO THE
EVENING. THIS SAME WIND PATTERN WILL HOLD BACK MVFR CEILING BUT NOT
QUITE BE STRONG ENOUGH TO KEEP CEILING ABOVE 5 KFT WHICH WILL BE
PERSISTENT THROUGH TONIGHT AND FRIDAY OUTSIDE OF OCCASIONAL BREAKS
FOR THE REST OF THIS AFTERNOON.

//DTW THRESHOLD PROBABILITIES...

* HIGH FOR CEILING 5000 FEET OR LESS TONIGHT THROUGH FRIDAY.

&&

.PREV DISCUSSION...ISSUED 328 AM EDT THU APR 28 2016

DISCUSSION...

RAIN SHOWERS TOOK THEIR TIME GETTING INTO SOUTHEAST MICHIGAN TONIGHT
LOWER LEVELS WERE RATHER DRY PER THE OOZ DTX SOUNDING LAST NIGHT.
SHOWERS WILL CONTINUE TO MOVE NORTHEAST ACROSS THE AREA EARLY THIS
MORNING AS THE CENTER OF THE LOW PASSES JUST TO THE SOUTH OF THE
AREA.  RAIN CHANCES WILL INCREASE DURING THE DAY TODAY AS THE
FRONTAL BOUNDARY LINGERS OVER THE AREA. LOW WILL THEN WEAKEN AND
BECOME AN OPEN WAVE AS IT PASSES ACROSS THE GREAT LAKES REGION LATER
THURSDAY NIGHT INTO FRIDAY.  MODEST MID LEVEL LAPSE RATES OVER THE
SOUTHERN THIRD OF THE CWA WILL SUPPORT THE CONTINUED CHANCES FOR
ELEVATED THUNDERSTORMS DURING THE DAY. WHILE MOISTURE WILL BE
MAINTAINED THROUGH THE DAY SUPPORTING PRECIP...DRIER LOW LEVELS AND
BETTER FORCING TO THE SOUTH WILL KEEP THINGS SOMEWHAT SUBDUED.
LATEST NAM IS SHOWING LESS OF A CHANCE FOR WIDESPREAD PRECIP WITH
OTHER MODELS SHOWING THE BULK OF THE PRECIP TO COME THROUGH THE
MORNING AND EARLY AFTERNOON HOURS.  LATEST HRRR IS ALSO JUST
ADVERTISING SCATTERED PRECIP WITH SOME EMBEDDED CONVECTION.  BY
FRIDAY AFTERNOON...THINGS START TO DRY OUT AS RIDING TAKES OVER.
THIS RIDING WILL HOLD THROUGH FRIDAY INTO EARLY SATURDAY BEFORE THE
NEXT WAVE APPROACHES FROM THE CENTRAL PLAIN.  TODAY WILL BE THE
COLDEST DAY IN THE EXTENDED FORECAST PERIOD AS EASTERLY FLOW AND
CLOUDS KEEP TEMPS CONFINED IN THE UPPER 40S. TEMPS DO START TO
MODERATE SLIGHTLY THIS WEEKEND INTO NEXT WEEK WITH HIGHS GETTING BACK
INTO THE 60S ALTHOUGH STILL ON THE COOL SIDE.

MARINE...

STEADY NORTHEAST FLOW BETWEEN HIGH PRESSURE OVER ONTARIO AND LOW
PRESSURE TRACKING INTO THE OHIO VALLEY WILL LEAD TO BUILDING WAVES
OVER LAKE HURON TODAY.  SMALL CRAFT ADVISORIES REMAIN IN EFFECT AS
WAVES BUILD INTO THE 3 TO 5 FOOT RANGE AT TIMES OVER MUCH OF THE
NEARSHORE WATERS OF LAKE HURON. THIS LOW WILL ALSO BRING A CHANCE
FOR A FEW THUNDERSTORMS TO LAKE ST CLAIR AND WESTERN LAKE ERIE.

HIGH PRESSURE WILL EXPAND BACK INTO THE CENTRAL GREAT LAKES TONIGHT
AND REMAIN POISED OVER THE AREA INTO SATURDAY...ALLOWING WINDS AND
WAVE HEIGHTS TO DECREASE. ANOTHER LOW PRESSURE SYSTEM WILL THEN LIFT
INTO THE OHIO VALLEY OR SOUTHERN GREAT LAKES SATURDAY NIGHT INTO
SUNDAY...BRINGING ANOTHER PERIOD OF STEADY ONSHORE FLOW LATE IN THE
WEEKEND. SMALL CRAFT ADVISORIES MAY BE NEEDED ONCE AGAIN. ALTHOUGH
WAVE CONDITIONS APPEAR TO BE MARGINAL AT THIS TIME...MUCH LIKE THE
EVENT TODAY.

HYDROLOGY...

AN AREA OF RAINFALL WILL LIFT NORTHWARD THROUGH SOUTHEAST MICHIGAN
TODAY AS LOW PRESSURE TRACKS ACROSS THE OHIO VALLEY. WHILE DRY LOW
LEVEL CONDITIONS WILL INITIALLY LIMIT RAINFALL POTENTIAL...SOME
LOCATIONS...GENERALLY SOUTH OF I-69...MAY RECEIVE UP TO ONE QUARTER
OF AN INCH OF RAIN BY LATE THIS AFTERNOON.

ANOTHER LOW PRESSURE SYSTEM WILL BRING THE NEXT CHANCE OF WIDESPREAD
RAIN LATE SATURDAY INTO SATURDAY NIGHT. AT THIS TIME...IT APPEARS
THAT ONE QUARTER TO ONE HALF AN INCH OF RAINFALL WILL BE POSSIBLE
WITH THIS SYSTEM. THE BEST CHANCE FOR STEADY RAINFALL WILL ONCE
AGAIN FOCUS SOUTH OF THE I-69 CORRIDOR.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LHZ421-422-
     441-442.

LAKE ST CLAIR...NONE.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LEZ444.

&&

$$

AVIATION.....BT
DISCUSSION...SS
MARINE.......DG
HYDROLOGY....DG


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



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