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000
FXUS63 KDTX 142312
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
712 PM EDT FRI JUN 14 2013


.AVIATION...

//DISCUSSION...

SURFACE HIGH PRESSURE WILL REMAIN IN FIRM CONTROL OF THE WEATHER
OVER SE MICHIGAN TONIGHT. ANY COMPLEXITIES AFFECTING AVIATION
OPERATIONS WILL BE ASSOCIATED WITH NORTHERLY WIND AUGMENTED BY LAKE
BREEZE INTERACTION DURING THE EVENING BEFORE THE HIGH SETTLES
OVERHEAD THROUGH SUNRISE SATURDAY. CONDITIONS WILL REMAIN VFR
THROUGH SATURDAY WITH A LIGHT WIND RETURNING FROM THE SOUTH AS HIGH
PRESSURE EXITS EASTWARD. THE FIRST SIGNS OF THE NEXT LOW PRESSURE
SYSTEM WILL BE IN THE FORM OF GRADUALLY THICKENING HIGH CLOUDS
THROUGH THE DAY.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 358 PM EDT FRI JUN 14 2013

SHORT TERM... REMAINDER OF TODAY THROUGH TONIGHT

AFTERNOON SURFACE OBSERVATIONS INDICATE THE CENTER OF HIGH PRESSURE
CARRYING IN A CORE OF DRY AIR FOR TONIGHT. SURFACE DEWPOINT WELL
DOWN INTO THE 30S WITH MID AFTERNOON TEMPS MOSTLY IN THE 60S OVER
NORTHERN LOWER DEPICTS THE NATURE OF THE AIR MASS AND POTENTIAL FOR
RADIATIONAL COOLING TONIGHT. THIS IS IN SHARP CONTRAST TO AFTERNOON
CONDITIONS IN SE MICHIGAN WHERE DEWPOINT IS REPORTED MOSTLY IN THE
50S, PARTIALLY DUE TO ADVECTION OF DRY AIR NOT YET THIS FAR SOUTH
AND PARTIALLY DUE TO ADVECTION BEING DISRUPTED BY PRESSURE FALLS
OVER INTERIOR LOWER MICHIGAN INDUCED BY SURFACE HEATING. TYPICAL OF
THIS TIME OF YEAR, THE RAPID FILLING OF THIS TROUGH TOWARD
SUNSET/POST PEAK HEATING WILL ALLOW THE INLAND RELEASE OF THE LAKE
HURON MARINE LAYER DURING THE EVENING, SO SURFACE DEWPOINT WILL
LIKELY LINGER IN THE 40S OVER OUR AREA TONIGHT RATHER THAN DROP INTO
THE 30S. THIS, COMBINED WITH CLEAR SKY AND CALM WIND OVERNIGHT, WILL
ALLOW RADIATIONAL COOLING TO TAKE MIN TEMPS DOWN INTO THE MID TO
UPPER 40S MOST LOCATIONS OUTSIDE OF THE LARGER URBAN AREAS.

LONG TERM...SATURDAY THROUGH THURSDAY

POTENTIALLY ACTIVE FRONT HALF OF THE EXTENDED PERIOD THROUGH MONDAY
NIGHT...QUIETING DOWN AFTER THAT. RIDGING OVER THE CENTRAL PLAINS
WILL BREAK DOWN AS A STRONG NORTHERN STREAM SHORTWAVE EJECTS OUT OF
AN UPPER LOW OVER SW CANADA LEADING TO A FLATTENED PROGRESSIVE FLOW
OVER THE NORTHERN HALF OF THE CONUS. A SECOND SOUTHERN STREAM
SHORTWAVE ROTATING AROUND THE RIDGE WILL ATTEMPT TO PHASE WITH THE
SHEARED OUT NORTHERN STREAM WAVE OVER THE WESTERN GREAT LAKES ON
SATURDAY NIGHT LEADING TO A PERIOD OF SHOWERS AND POSSIBLY
THUNDERSTORMS. NOT FEELING OVERLY CONFIDENT ON THE SETUP OVER
SOUTHERN MI FOR A WIDESPREAD EVENT AS SEVERAL PARAMETERS ARE WEAK
OVER THE AREA. OVERALL WE ARE LOOKING AT STRONGEST AREAS OF SHEAR TO
BE LOCATED OVER THE NORTHERN GREAT LAKES AND THE OHIO VALLEY WITH A
RELATIVE MINIMUM OVER SE MI. A DECENT 700-850MB THETA-E RIDGE WITH A
RELATIVELY TIGHT LEADING GRADIENT WILL WORK INTO THE REGION SATURDAY
AFTERNOON BUT WILL BE WEAKENING AND REORIENTING WHILE MOVING ACROSS
THE AREA. THIS ALSO PRECEDES ANY NOTABLE INSTABILITY WHICH DOES NOT
LOOK TO MOVE IN UNTIL AFTER 21Z SATURDAY FOR OUR WESTERN COUNTIES
WHEN THE CAP AROUND 700MB STARTS BREAKING DOWN...AS INDICATED ON
MODEL SOUNDINGS. BULK OF THE PRECIP LOOKS TO OCCUR BETWEEN 00Z AND
12Z SUNDAY AS THE SFC BOUNDARY TIED TO THE NORTHERN STREAM WAVE
MOVES THROUGH WITH AROUND 1000 J/KG OF CAPE AND INCREASING LAPSE
RATES. LLJ LOOKS TO PRECEDE THE FRONTAL BOUNDARY WHICH COULD HELP
INTENSIFY ANY PREFRONTAL SHOWERS THAT DEVELOP. AMPLY MOISTURE IN THE
COLUMN...PWATS GREATER THEN 1.50 INCHES...WILL MEAN HEAVY RAINFALL
MAY OCCUR WITH ANY STORM THAT GOES UP. A CONCERN WITH THE SETUP IS
THAT THE SOUTHERN STREAM WAVE WILL TRACK MORE SOUTHEASTWARD AROUND
THE RIDGE WHICH TAKES THE CENTER OF THE SFC LOW SOUTH OF THE MI
BOARDER. MODELS ARE HINTING AT THIS WHICH OCCURS QUITE OFTEN WITH
SIMILAR SETUPS...WHICH WOULD INITIATE CONVECTION TO OUR SOUTH AND
LIMIT ACTIVITY OVER SE MI. GOING WITH LIKELY POPS FOR SATURDAY NIGHT
AS IT DOES LOOK GOOD FOR AN AREA OF SHOWERS REGARDLESS OF WHETHER WE
CAN GET STRONG THUNDERSTORMS TO DEVELOP OR NOT.

EXPECT PRECIP TO LINGER INTO SUNDAY BEFORE TAPERING OFF THROUGH THE
DAY. SUBSIDENCE IN THE WAKE OF THE SYSTEM SHOULD HELP BRING A DRY
PERIOD SUNDAY NIGHT BEFORE A SECOND SHORTWAVE DIVES SOUTH THROUGH
THE AREA ON MONDAY. MODELS ARE STRUGGLING QUITE A BIT BEYOND THIS
POINT TRYING TO FIRE MORE CONVECTION WITH THIS WAVE EVEN WITH THE
LACK OF ANY INSTABILITY AND DRIER COLUMN TO WORK WITH. WILL LEAVE
CHANCE POPS IN FOR MONDAY AND MONDAY NIGHT UNTIL WE CAN GET A SENSE
OF THE STRENGTH OF THIS WAVE AND WHAT KIND OF ENVIRONMENT IT WILL
HAVE TO WORK WITH.

HIGH PRESSURE THEN BUILDS BACK INTO THE REGION MIDWEEK AS THE
MIDLEVEL RIDGE REBUILDS OVER THE PLAINS. HEIGHTS WILL STAY FAIRLY
STEADY THROUGH THE WEEK WHICH MEANS TEMPS WILL BE FAIRLY
STEADY...DEPENDENT ON LINGERING CLOUD COVER AND PERIODS OF
CONVECTION. FORECAST TEMPS FALL JUST SHY OF NORMAL FOR THIS TIME OF
YEAR...AROUND 79 FOR DTW AND 77 FOR FNT...WITH VALUES GENERALLY IN
THE MID 70S.

MARINE...

THE PASSAGE OF HIGH PRESSURE OVER THE GREAT LAKES WILL ALLOW FOR
LIGHT AND VARIABLE WIND THROUGH LAKE HURON AND LOWER MICHIGAN
TONIGHT FOLLOWED BY A MODEST RETURN TO SOUTHERLY DURING SATURDAY.
SOME DISRUPTION OF MARINE CONDITIONS IS POSSIBLE DURING THE WEEKEND
DUE TO SHOWERS AND THUNDERSTORMS, BUT THIS SHOULD BE MOSTLY SATURDAY
NIGHT AS THE NEXT LOW PRESSURE SYSTEM MOVES THROUGH NORTHERN
ONTARIO. WIND AND WAVE CONDITIONS WILL OTHERWISE BE FAVORABLE OVER
THE NEXT SEVERAL DAYS UNTIL PERHAPS 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.....KURIMSKI
SHORT TERM...BT
LONG TERM....DRK
MARINE.......BT


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