Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 030354
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EDT SAT MAY 2 2015


.AVIATION...

DRY LOW LEVEL AIR FUNNELING INTO AREA ON SOUTH TO SOUTHWEST FLOW
AROUND LARGE HIGH PRESSURE POSITIONED SOUTHEAST OF THE REGION AND
MAINTAIN VFR CONDITIONS THROUGH THE FORECAST PERIOD. WIND GUSTS OF
15 TO 20 KNOTS WILL BE POSSIBLE BY MIDDAY SUNDAY...ESPECIALLY FOR
KFNT/KMBS AS THE PRESSURE GRADIENT TIGHTENS TO SOME EXTENT.

//DTW THRESHOLD PROBABILITIES...

* NONE.

&&

.PREV DISCUSSION...ISSUED 326 PM EDT SAT MAY 2 2015

SHORT TERM...TONIGHT

CONUS IR VIEW SUGGESTS LITTLE REASON TO DEVIATE FROM MOSTLY CLEAR
FORECAST FOR TONIGHT. NOTHING MORE THAN PARTIAL COVERAGE OF EPISODIC
MID/HIGH CLOUD ADVECTING EAST WITHIN FLAT MID-LEVEL FLOW WILL
TRANSIT AREA SKIES OVERNIGHT. SURFACE HIGH PRESSURE OVER THE OHIO
VALLEY WILL MIGRATE EAST ALLOWING FOR AN INCREASE IN RETURN FLOW,
ESPECIALLY TOWARD MORNING. MODERATE PGF SUGGESTS DECOUPLING MAY BE
HARD TO COME BY WHICH WILL HELP HOLD TEMPERATURES UP DESPITE CLEAR
SKIES. INCREASING WARM ADVECTION WILL CONTRIBUTE TO SOME WEAK ASCENT
TOWARD MORNING BUT THE COLUMN WILL BE TOO DRY YET TO SUPPORT WAA-
FORCED CLOUD COVER. TRENDED LOWS A TOUCH WARMER GIVEN LIGHT GRADIENT
AND WEAK WAA. SUSPECT TEMPS WILL BOTTOM OUT IN THE LOW 50S BEFORE
LEVELING OFF OR RISING A BIT TOWARD MORNING.

LONG TERM...

STRENGTHENING LOW LEVEL SOUTHWEST FLOW ON SUNDAY WITH UPPER LEVEL
RIDGE AXIS IN PLACE OVER THE CENTRAL GREAT LAKES WILL SUPPORT
TEMPERATURES INTO THE UPPER 70S TO AROUND 80 DEGREES...AS
850 MB TEMPS RISE BETWEEN 11 TO 12 C.

A COLD FRONT IS ON TRACK TO MOVE THROUGH SOUTHEAST MICHIGAN ON
MONDAY...BUT 500 MB HEIGHT FALLS ARE CONFINED TO ONTARIO...THUS NO
UPPER LEVEL SUPPORT TO WORK WITH. WILL JUST BE RELYING ON MOISTURE
TRANSPORT...INSTABILITY... AND LOW LEVEL CONVERGENCE/FGEN WITH THE
FRONT. 850 MB DEW PTS ARE PROGGED TO REACH OR SLIGHTLY EXCEED 10
C...BUT SUBSTANTIAL INSTABILITY LOOKS TO BE GENERALLY LACKING...WITH
MUCAPES UNDER 1000 J/KG. THERE WILL BE MODERATE WIND FIELDS TO WORK
WITH...BUT EXPECTATIONS ARE FOR SUB-SEVERE ACTIVITY DUE TO LIMITED
INSTABILITY. CONVECTIVE DEBRIS AROUND IN THE MORNING AND INITIATION
TIME WILL DICTATE HIGHS FOR MONDAY...BUT HIGHS IN THE MID 70S TO
AROUND 80 DEGREES LOOKS TO BE THE MIDDLE GROUND BASED ON THESE
NEGATIVE FACTORS. THE FRONT LOOKS TO BECOME WEST-EAST ALIGNED
(PARALLEL TO MEAN FLOW) AND GETTING HUNG UP NEAR THE SOUTHERN
MICHIGAN BORDER MONDAY EVENING...WITH GOOD 925-850 MB TEMP
GRADIENT/FGEN STRUNG ACROSS SOUTHERN LOWER MICHIGAN...SUPPORTING
GOOD CHANCE/LIKELY POPS TOWARD THE OHIO BORDER INTO MONDAY NIGHT.

CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY ALONG THE
STALLED FRONT WITH THE BEST CHANCES ALONG THE OHIO BORDER. THE
DIFFUSE FRONT WILL LIFT BACK NORTHWARD TUESDAY NIGHT AND WEDNESDAY
AS UPPER LEVEL HEIGHTS RISE LOCALLY IN RESPONSE TO ENERGY LIFTING
INTO THE PLAINS STATES. A FEW SHOWERS AND STORMS ARE POSSIBLE WITH
THIS PROCESS...BUT LACK OF MIDLEVEL FORCING AND STABLE EASTERLY
COMPONENT TO THE FLOW SHOULD KEEP COVERAGE LIMITED. EVEN WARMER FOR
LATE WEEK INTO SATURDAY AS SOUTHERLY FLOW DEVELOPS LOCALLY IN
RESPONSE TO LOW PRESSURE OVER THE NORTHERN PLAINS. UPPER RIDGE SHOWN
TO BREAK DOWN SOMEWHAT LATE IN THE PERIOD AS SHORTWAVES TRAVERSE THE
GREAT LAKES...CHANCE POPS IN PLACE FRIDAY AND SATURDAY.

MARINE...

MARINE CONDITIONS WILL REMAIN FAVORABLE THROUGH TOMORROW AS
SOUTHWEST WINDS ALLOW WARM AIR TO STREAM INTO THE GREAT LAKES
REGION. THERE WILL BE A MODEST UPTICK IN WIND DURING SUNDAY BUT
STABILITY WILL BE HIGH OVER THE OPEN WATERS WHICH WILL LIMIT WAVE
GROWTH. THE NEXT COLD FRONT WILL SLIDE THROUGH LAKE HURON AND LOWER
MICHIGAN LATE SUNDAY NIGHT AND MONDAY...AND THEN STALL NEAR THE OHIO
BORDER TUESDAY. SHOWERS AND THUNDERSTORMS ARE LIKELY DURING THIS
TIME...BUT MOST OF THE ACTIVITY WILL FOCUS OVER THE SOUTHERN LAKE
HURON BASIN AND SOUTHWARD INTO LAKE ERIE AFTER THE FRONTAL PASSAGE
MONDAY.

&&

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

$$

AVIATION.....DG
SHORT TERM...JVC
LONG TERM....SF/DT
MARINE.......SF


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


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