Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 290714
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
314 AM EDT SAT AUG 29 2015

.SHORT TERM...TODAY AND TONIGHT

MERGING UPPER WAVES (NORTHERN MINNESOTA/IOWA) EARLY THIS
MORNING...WITH MAX HEIGHT FALL CENTER/RIGHT ENTRANCE REGION FORCING
OF UPPER LEVEL JET LOOKING TO TRACK THROUGH CENTRAL LOWER
MICHIGAN/LAKE HURON...SUPPORTING HIGHER BASED SHOWER ACTIVITY THIS
MORNING...MAINLY NORTH OF M-59. CONTINUED MOISTURE TRANSPORT THROUGH
THE DAY AND SHEARED OUT UPPER LEVEL PV FILAMENT/500 MB TROUGH AXIS
DRIFTING THROUGH THE AREA WILL SUPPORT CHANCE POPS FARTHER SOUTH
TOWARD THE OHIO BORDER THROUGH TONIGHT AS MAIN MOISTURE AXIS (PW
VALUES 1.5+ INCHES) ALSO FOLDS OVER INTO EAST-WEST ALIGNMENT. TEPID
DIURNAL INSTABILITY PERHAPS LEADING TO AN ISOLATED THUNDERSTORM.
SURFACE RIDGE AXIS RELUCTANT TO BUDGE DURING THE DAY...WITH WEAK
SURFACE TROUGH/WARM FRONT ATTEMPTING TO EXPAND EAST ALONG THE
SOUTHERN MICHIGAN BORDER TONIGHT...PROVIDING FOCUS FOR POSSIBLE
ACTIVITY...WITH MODEST INSTABILITY IN PLACE AS SHOWALTER INDEX
HOVERS AROUND ZERO. CLOUDS EXPECTED TO LIMIT DIURNAL SWING...HOLDING
MAXES IN THE 70S DURING THE DAY...AND LOW TO MID 60S TONIGHT.

&&

.LONG TERM...SUNDAY THROUGH FRIDAY

MID LEVEL TROUGH AXIS ANCHORED OVERHEAD SUNDAY MORNING WILL SLOWLY
EXIT TO THE EAST THROUGH THE DAY...THE LEAD EDGE OF THE INBOUND
INCREASING UPPER HEIGHT FIELD LOOMING ACROSS THE PLAINS TAKING A
PROGRESSIVE HOLD LOCALLY OVER THE NEXT 24-36 HOURS.  MOIST RESIDUAL
BOUNDARY LAYER/NEAR SURFACE CONDITIONS IN COMBINATION WITH DAYTIME
HEATING WILL YIELD A WEAKLY UNSTABLE ENVIRONMENT DURING THE DAYLIGHT
PERIOD.  MID LEVEL TROUGH POSITIONING SUGGESTS THERE MAY BE A NARROW
WINDOW FOR SOME RENEWED CONVECTIVE DEVELOPMENT WITHIN THE TRAILING
SHEAR AXIS/CYCLONIC FLOW...ALTHOUGH MOST RECENT MODEL GUIDANCE
TEMPERING THIS RESPONSE PARTICULARLY ACROSS NORTHERN SECTIONS.  WITH
PROJECTED HIGHS /80 DEGREES/ AT THE CUSP OF CONVECTIVE
TEMPERATURES...THIS POINTS TOWARD SIMPLY A LOW END
POTENTIAL/COVERAGE OF SHOWERS AND THUNDERSTORMS FOR SUNDAY.

CONDITIONS THROUGHOUT THE UPCOMING WORK WEEK WILL LARGELY BE DEFINED
BY LIGHT SOUTHWEST LOW LEVEL FLOW TUCKED BENEATH QUASI-STATIONARY
UPPER RIDGING.  THIS PATTERN WILL FAVOR A TRANSTION BACK TOWARD
ABOVE NORMAL WARMTH...WITH DAYTIME READINGS CLIMBING WELL INTO 80S
THROUGH THE WEEK.  LIMITED POTENTIAL FOR CONVECTIVE DEVELOPMENT
THROUGH THIS TIME GIVEN THE ILL-DEFINED/NEGLIBIBLE FORCING AND WARM
MID LEVEL TEMPERATURES.  MID RANGE GUIDANCE DOES CENTER AN
OPPORTUNITY ON WEDNESDAY AS A WEAK IMPULSE BRIEFLY WORKS THROUGH THE
EXISTING RIDGE CENTER.

&&

.MARINE...

GENERALLLY LIGHT WINDS WILL EXIST ACROSS ALL MARINE AREAS THROUGH
THE WEEKEND AS BROAD HIGH PRESSURE REMAINS IN PLACE.  A LIGHT
SOUTHWEST WIND WILL CONTINUE INTO EARLY NEXT WEEK WITH HIGH PRESSURE
CENTERED OVER THE EASTERN OHIO VALLEY.

&&

.AVIATION...ISSUED 1148 PM EDT FRI AUG 28 2015

NO SUBSTANTIVE CHANGE TO FORECAST THIS MORNING. JUST HIGH CLOUDS AND
AND A SHORT-LIVED VFR -RA THREAT FOR KMBS TOWARD DAYBREAK.
CONFIDENCE IN RAIN SHIELD HOLDING TOGETHER INTO MIDDAY SATURDAY HAS
INCREASED SUFFICIENTLY TO INCLUDE A TEMPO FOR HIGH BASED -SHRA NORTH
OF PTK. EXPECTATION IS THAT THIS ACTIVITY WILL TEND TO WASH OUT WITH
DIURNALLY DRIVEN -SHRA EVENTUALLY TAKING ITS PLACE ACROSS THE SOUTH,
HENCE THE LATER TIMING FOR THE DETROIT VICINITY. DAYTIME HEATING
WILL LIKEWISE SUPPORT A DEVELOPING CEILING AROUND 5KFT WHICH WILL
HANG TOUGH THROUGH THE PERIOD AS MOISTURE QUALITY INCREASES DUE TO
AN ELEVATED WARM FRONT SETTLING OVER CENTRAL LOWER MICHIGAN. WINDS
WILL REMAIN LIGHT AND PREDOMINANTLY SOUTHERLY BUT MAY BE VARIABLE AT
TIMES THROUGH THE PERIOD. WARM COLUMN AND EXTENSIVE MID-LEVEL CLOUD
COVER SHOULD SIGNIFICANTLY LIMIT THUNDERSTORM POTENTIAL.

FOR DTW...CONFIDENCE IN CEILINGS AOB 5KFT WILL INCREASE WITH TIME ON
SATURDAY AFTN AND EVENING. CURRENT EXPECTATION IS FOR CEILING TO
PERSIST THROUGH MUCH OR ALL OF SATURDAY NIGHT.

//DTW THRESHOLD PROBABILITIES...

* MEDIUM IN CIGS AOB 5KFT SATURDAY AFTN THROUGH SATURDAY NIGHT.

&&

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

$$

SHORT TERM...SF
LONG TERM....MR
MARINE.......MR
AVIATION.....JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).



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