000
FXUS63 KDTX 161738
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
138 PM EDT SUN JUN 16 2013


.AVIATION...

//DISCUSSION...

THE JET STREAM AXIS WILL REMAIN IN A WEST TO EAST FASHION DIRECTLY
OVER THE GREAT LAKES REGION. THIS WILL MAKE DRY AIR ADVECTION A
STUBBORN PROCESS WITHIN THE LOW LEVELS. THERE REMAINS ENOUGH NEAR
SURFACE MOISTURE TO CARRY A SLIGHT CHANCE POP FOR A SHOWER OR
THUNDERSTORM THIS AFTERNOON BETWEEN 20-23Z. HOWEVER...THE
POTENTIAL REMAINS TOO LOW TO CARRY AN EXPLICIT MENTION. ADVECTIONS
WILL REMAIN WEAK AGAIN TONIGHT WITH ANY BACKGROUND MIDLEVEL
INVERSIONS NON-EXISTENT. BELIEF IS THAT ONCE WE CAN MIX OUT CLOUDS
TOWARDS SUNDOWN...SKIES WILL REMAIN SKC FOR THE OVERNIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE THAT CEILINGS BELOW 5KFT WILL BREAK THIS
  AFTERNOON.

* HIGH CONFIDENCE FOR A VERY LOW THUNDERSTORM PROBABILITY.

&&

.PREV DISCUSSION...ISSUED 324 AM EDT SUN JUN 16 2013

SHORT TERM...TODAY AND TONIGHT

EASTWARD PROGRESSION OF THE LOW-LEVEL JET AXIS WILL FACILITATE AN
EARLY EXIT OF ONGOING SHOWER AND THUNDERSTORM ACTIVITY THIS MORNING
WITH ORGANIZED PRECIP FORECAST TO CLEAR THE AREA BY 12Z. THE
REMAINDER OF THE DAY WILL BE CHARACTERIZED BY THE INFILTRATION OF
THE DEEP COLUMN OF DRY AIR NOTED OVER THE NORTHERN PLAINS THIS
MORNING AS THE SAGGING/DISTURBED MID-LEVEL HEIGHT FIELD AND
ASSOCIATED UPPER JET SHIFT SOUTH OF THE AREA. H7 PLANVIEWS OF
THETA-E DEPICT THE SOUTHEASTWARD PUSH OF DRY AIR WELL, WITH THE
THETA-E GRADIENT MAKING A QUICK PUSH THROUGH THE FORECAST AREA
BETWEEN 18Z AND 21Z. PRIOR TO THAT TIME, REMNANT MOISTURE AND
INCREASING DIURNAL HEATING IN THE PRESENCE OF WEAK MID-LEVEL
SHORTWAVE FORCING FOR ASCENT ARE SUFFICIENT JUSTIFICATION FOR
MENTION OF CHANCE POPS TO ACCOUNT FOR THE POTENTIAL FOR ISOLATED TO
SCATTERED ACTIVITY THROUGH THE FIRST HALF OF THE DAY.

EMERGENCE OF WELL-MIXED WESTERLY FLOW WILL COINCIDE WITH THE ARRIVAL
OF MAXIMUM MID-LEVEL DRYING AND THE PEAK IN DIURNAL HEATING. AS A
RESULT, BOUNDARY LAYER GROWTH TO 850MB WILL SUPPORT HIGH
TEMPERATURES NEARING 80 DEGREES THIS AFTERNOON DESPITE WHAT WILL
LIKELY BE A HEALTHY COVERAGE OF STRATOCU AND BREEZY WESTERLY WINDS.
AFTERNOON ARRIVAL OF DRY AIR WILL ALSO SUBSTANTIALLY LIMIT
THUNDERSTORM POTENTIAL DESPITE PROGGED SBCAPE VALUES AROUND 1500
J/KG. STILL, IT WILL NOT BE OUT OF THE QUESTION FOR A PERSISTENT
UPDRAFT OR TWO TO LOCALLY WORK OVER THEIR ENVIRONMENT AND SURVIVE
LONG ENOUGH TO PRODUCE SOME THUNDER AND A BRIEF HEAVY DOWNPOUR. AS A
RESULT, THE INHERITED LOW CHANCE POPS REMAIN IN PLACE SOUTH OF
INTERSTATE 69 THROUGH 00Z THIS EVENING. MILD BUT DRY CONDITIONS CAN
BE EXPECTED TONIGHT AS THE GRADIENT WINDS BACK TO SOUTHWESTERLY
AHEAD OF THE NEXT WAVE.

LONG TERM... MONDAY THROUGH SATURDAY

BROADER MID LEVEL TROUGHING ANCHORED ACROSS SOUTH-CENTRAL CANADA
WILL UNDERGO SOME STRENGTHENING WITH TIME OVER THE NEXT 48 HOURS
WITH A CLOSED LOW EVOLVING OVER HUDSON BAY.  THIS WILL PROMPT THE
SOUTHERN EXTENSION OF THE MAIN HEIGHT FALL REGION TO SQUEEZE INTO
THE PREVAILING MID LEVEL WESTERLIES POSITIONED OVER THE GREAT
LAKES.  THIS PROCESS WILL ALLOW A COLD FRONTAL BOUNDARY TO SETTLE
SOUTHWARD THROUGH LOWER MICHIGAN MONDAY AND MONDAY NIGHT.  SOLID
WINDOW WILL EXIST TO CAPITALIZE ON DAYTIME HEATING WITH THE FRONTAL
PASSAGE CENTERED LOCALLY ON THE AFTERNOON/EVENING PERIOD.  ASSUMING
SOME PESKY HIGHER LEVEL CLOUD DEBRIS DOES NOT DISRUPT THE DIABATIC
HEATING CONTRIBUTION...A STEADY LOW LEVEL WEST-SOUTHWEST GRADIENT
WILL SUPPORT HIGHS OF LOWER TO MIDDLE 80S ACROSS THE SOUTHERN
TWO-THIRDS OF THE AREA.  THE DEGREE OF DESTABILIZATION WILL BE
LIMITED TO SOME EXTENT BY A RELATIVELY MODEST MOISTURE PROFILE...
ESPECIALLY WITHIN THE BOUNDARY LAYER WHERE A LACK OF BETTER
PRE-FRONTAL MOISTURE TRANSPORT WILL LEAVE DEWPOINTS HOVERING IN THE
MID/UPPER 50S.  NONETHELESS THE INCREASING FRONTAL CONVERGENCE...
PERHAPS AIDED BY SOME FORM OF WEAK MID LEVEL ENERGY AND UPPER JET
FORCING...WILL SUPPORT SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT
GIVEN THE FAVORABLE FRONTAL TIMING.  TREMENDOUS LARGELY
UNIDIRECTIONAL WIND FIELD WILL BE IN PLACE...0-6 KM BULK SHEAR IN
EXCESS OF 40 KNOTS.  THEREFORE...POTENTIAL IS THERE FOR ANY STRONGER
UPDRAFTS TO QUICKLY ATTAIN BETTER ORGANIZATION...PRESENTING AT LEAST
AN ISOLATED RISK FOR SEVERE WIND GUSTS/HAIL.

STEADY BUT BRIEF TRANSITION TO MID LEVEL NORTHWEST FLOW ON THE EDGE
OF THE SOUTHERN CANADIAN TROUGH INTERFACE WILL EFFECTIVELY SHIFT THE
FRONT SOUTH OF THE REGION BY TUESDAY MORNING.  LOW LEVEL
ANTICYCLONIC FLOW WILL THEN TAKE CONTROL FOR TUESDAY AS
STRENGTHENING HIGH PRESSURE FILLS SOUTHEAST TOWARD THE WESTERN GREAT
LAKES.  THIS WILL USHER IN A COOLER AND LESS HUMID AIRMASS...
850-925 MB THERMAL LAYER DROPPING A GOOD 6-7 DEGREES.  A HIGH DEGREE
OF SUNSHINE WILL BE THE SOURCE FOR THE DIURNAL RECOVERY...HIGHS
RANGING FROM MID 70S SOUTH TO MID 60S IN THE THUMB.  HIGH PRESSURE
CENTER WORKS IN BY TUESDAY NIGHT...SETUP CERTAINLY POINTS TO A
FAVORABLE RADIATIONAL COOLING ENVIRONMENT.  LOWS TUESDAY NIGHT MAY
ARRIVE JUST SHY OF RECORD TERRITORY /DTW 46...FNT 44...MBS 42/ BUT
THIS AIRMASS WOULD SUPPORT READINGS OF MIDDLE 40S IN THE COLDEST
LOCALES.

GENERAL SURFACE RIDGING TUCKED BENEATH WEAK WEST-NORTHWEST MID LEVEL
FLOW WILL MAINTAIN DRY AND STABLE CONDITIONS THROUGH THURSDAY.  NO
REAL CHANGE TO OVERALL CONDITIONS ON WEDNESDAY WITH NEUTRAL
THERMAL/MOISTURE ADVECTION AND MINIMAL NOTED CHANGE IN THE UPPER
HEIGHT FIELD.  A SLOW INCREASE IN MEAN THICKNESSES AS HEIGHTS SLOWLY
BUILD WILL INITIATE THE START OF A PROGRESSIVE WARMING TREND
BEGINNING ON THURSDAY.  SOME DEGREE OF UPPER RIDGING WILL TAKE FORM
UPSTREAM BY THE END OF THE WEEK...WITH THIS HEIGHT FIELD ENTERING
THE PICTURE LOCALLY BY NEXT WEEKEND.  THIS POINTS TOWARD A RETURN TO
MORE TYPICAL LATE JUNE WARMTH AND HUMIDITY DURING THIS TIME.

MARINE...

FAVORABLE MARINE CONDITIONS WILL PERSIST ACROSS AREA WATERWAYS WITH
A BENIGN PATTERN IN PLACE, ALTHOUGH SOME DISRUPTION WILL BE POSSIBLE
THROUGH EARLY THIS MORNING DUE TO THUNDERSTORM ACTIVITY. WIND AND
WAVE CONDITIONS WILL OTHERWISE REMAIN FAVORABLE UNTIL LATE MONDAY
WHEN THE NEXT COLD FRONT IS DUE THROUGH THE REGION.

&&

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

&&

$$

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


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