Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 011934
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
334 PM EDT SUN MAY 1 2016

.DISCUSSION...

MOISTURE/CLOUDS TRAPPED BENEATH AN INVERSION AND NORTHEAST FLOW OFF
THE LAKES HAVE KEPT TEMPERATURES COOL TODAY...GENERALLY IN THE UPPER
40S TO LOW 50S THIS AFTERNOON. MAY SEE ONLY A FEW BREAKS IN CLOUDS
THIS EVENING BEFORE CLOUD SHIELD ASSOCIATED WITH THE NEXT AREA OF
LOW PRESSURE BEGINS TO SPILL OVER THE AREA.

UPPER LOW OVER NE/IA WILL TRACK EAST TONIGHT...OPENING AS IT BEGINS
TO PHASE WITH THE BAGGY TROUGH OVER THE GREAT LAKES AND EASTERN
CANADA. UPPER ENERGY IS EXPECTED TO PASS THROUGH SOUTHERN MICHIGAN
AND THE NORTHERN OHIO VALLEY TONIGHT...WITH THE SURFACE LOW CENTER
LOOKING TO PASS TO OUR SOUTH OVER OHIO. SYSTEM WILL TRACK ALONG A
FRONTAL BOUNDARY DRAPED OVER THE REGION...ELEVATED PORTIONS OF WHICH
WILL REMAIN OVER SOUTHERN LOWER MICHIGAN. CONVERGENCE/ASCENT ALONG
THE FRONT LOOKS TO INCREASE AS THE SYSTEM RIDES ALONG THE BOUNDARY
TONIGHT...WITH FORCING ALSO GETTING A BOOST FROM LEFT EXIT REGION
FORCING FROM A JET STREAK TO OUR SOUTH. THIS SHOULD PROMPT A NICE
RESPONSE IN THE FORM OF RAIN TONIGHT...WITH EMBEDDED CONVECTION AS
MID-LEVEL LAPSE RATES STEEPEN TO 7-8 C/KM. HIGHEST RAIN TOTALS WILL
BE SITUATED ALONG/SOUTH OF THE M-59 CORRIDOR...CLOSER TO WHERE A
WEAK LOW-LEVEL JET WILL BE FEEDING ADDITIONAL MOISTURE INTO THE
AREA. DEFORMATION AREA AND ASSOCIATED RAIN LOOK TO PASS EAST OF THE
AREA BY SUNRISE AS THE LOW QUICKLY SCOOTS TOWARDS THE EAST COAST.

HIGH PRESSURE CENTERED OVER THE NORTHERN GREAT LAKES WILL EXPAND
BACK INTO THE AREA MONDAY AS THE LOW DEPARTS. COOLER AIR SPILLING IN
ALOFT BEHIND THE LOW...ENHANCED BY ANOTHER UPPER WAVE PASSING FROM
ONTARIO INTO QUEBEC...WILL PROMOTE STEEP LAPSE RATES UP THROUGH
ABOUT 750MB AS SURFACE HEATING COMMENCES. MODEL SOLUTIONS ARE
INCONSISTENT WITH HOW MUCH MOISTURE WILL BE PRESENT UP THROUGH AN
INVERSION POSITIONED JUST ABOVE THIS LEVEL...WITH NAM MUCH MORE
MOIST THAN GFS. NAM WOULD SUPPORT DEVELOPMENT OF SCATTERED SHALLOW
CONVECTION AND PERHAPS SOME MORNING DRIZZLE AS SOME DRYING OCCURS IN
THE MID LEVELS. WILL HOLD OFF ON ADDING RAIN MENTION AND STICK WITH
JUST CLOUDS BASED ON GFS/EURO...AS NAM SOMETIMES CARRIES A BIAS WITH
TOO MUCH LOW-LEVEL MOISTURE. WARMING WILL BE TEMPERED BY SOME CLOUD
COVER (ESPECIALLY SOUTH) AND NORTH FLOW...BUT HIGHS SHOULD BE ABLE
TO REACH THE MID 50S TO NEAR 60.

SOUTHWEST FLOW AND MIXING ON TUESDAY AHEAD OF TROUGH APPROACHING
FROM THE NORTH SHOULD BRING NOTICEABLY WARMER TEMPERATURES...WITH
MAX TEMPS EXPECTED TO REACH INTO THE MID OR PERHAPS EVEN UPPER 60S.
SURFACE TROUGH AXIS AND COLD FRONT LOOK TO WORK DOWN THROUGH
SOUTHEAST MICHIGAN LATE TUESDAY NIGHT PER LATEST MODEL CONSENSUS.
THIS WILL BRING ANOTHER CHANCE FOR RAIN SHOWERS.

CUTOFF UPPER LOW PROGGED BY GLOBAL MODELS TO DRIFT OVER SOUTHEAST
MICHIGAN WEDNESDAY WITH LOWER HEIGHTS LINGERING INTO EARLY THURSDAY.
RESULT WILL BE COOL AND SHOWERY WEATHER. CURRENT INDICATIONS ARE
THAT THE LARGE RIDGE OVER THE CENTRAL US WILL EXPAND EASTWARD INTO
THE GREAT LAKES FRIDAY AND SATURDAY...LEADING TO A SOLID WARMING AND
DRYING TREND.

&&

.MARINE...

NORTHEAST WINDS CONTINUE ACROSS THE CENTRAL GREAT LAKES INTO
TONIGHT...GENERALLY LIGHT...BUT SOME CHANNELING ACROSS SAGINAW BAY
TO SUPPORT GUSTS ABOVE 20 KNOTS INTO THE EVENING. A WEAK PRESSURE
GRADIENT TOMORROW WILL SUPPORT LIGHT AND VARIABLE WINDS...CONTINUING
INTO TUESDAY. A COLD FRONT IS FORECASTED TO SWING THROUGH THE
CENTRAL GREAT LAKES...CAUSING WINDS TO SHIFT TO THE NORTHWEST BY
WEDNESDAY EVENING...BUT STILL 20 KNOTS OR LESS.

&&

.HYDROLOGY...

A COMPACT AND FAST-MOVING SYSTEM WILL MOVE THROUGH THE AREA
TONIGHT...WITH AROUND HALF AN INCH OF RAIN EXPECTED ALONG AND SOUTH
OF M59 CORRIDOR. THE BULK OF RAINFALL IS FORECAST TO OCCUR
BETWEEN MIDNIGHT AND 6 AM LOCAL TIME. NO FLOODING IS EXPECTED...WITH
JUST MODEST RISE IN STREAMS AND RIVERS...ALONG WITH PONDING/STANDING
WATER IN NORMALLY PRONE LOW LYING AREAS.

&&

.AVIATION...ISSUED 102 PM EDT SUN MAY 1 2016

LOW CLOUDS WILL BE LOCKED INTO TOMORROW ACROSS SOUTHEAST
MICHIGAN WITH NORTHEAST SURFACE WINDS. CEILINGS PREDOMINATELY IN THE
IN IFR RANGE FOR MAJORITY OF TIME PERIOD ACROSS SOUTHERN TAF
SITES...BUT PERIOD OF LOW MVFR EARLY THIS EVENING STILL FORECASTED
BEFORE NEXT BATCH OF RAIN SPREADS IN LATE THIS EVENING...SENDING
CEILINGS/VSBYS BACK INTO THE BORDERLINE IFR/LIFR RANGE OVERNIGHT.
BACK INTO MVFR RANGE TOMORROW. SLIGHTLY DRIER AIR COMING IN FROM
THE NORTH WILL PROVIDE MBS WITH THE BETTER AVIATION CONDITIONS...AS
THE NORTHERN RAIN SHIELD MAY MISS THE TERMINAL TONIGHT ALL
TOGETHER....WITH VFR CONDITIONS EVEN POSSIBLE.

FOR DTW...
LOW CLOUDS (IFR) HAVE DIFFICULT TIME BEING DISLODGED...BUT STILL
WILL HOLD ONTO A PERIOD OF LOW MVFR CEILINGS EARLY THIS EVENING
OUT AHEAD OF THE NEXT BATCH OF RAINFALL...WITH LOOKS TO ARRIVE
AROUND/BY MIDNIGHT...QUICKLY SENDING CONDITIONS BACK INTO IFR/BORDERLINE
LIFR 6-12Z. SLOW DRYING OCCURRING DURING THE DAY ON MONDAY...LIFTING
CEILINGS BACK INTO MVFR...WITH SCATTERED CLOUDS POSSIBLE BY DAY`S
END.

//DTW THRESHOLD PROBABILITIES...

* HIGH FOR CIG AOB 5KFT

* LOW FOR CIG AOB 200 FT 5-12Z.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

DISCUSSION...HLO/DT
MARINE.......SF
HYDROLOGY....SF
AVIATION.....SF


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


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