Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000 FXUS63 KDTX 011710 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 110 PM EDT SAT AUG 1 2015 .AVIATION...
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PASSING WEAK SHORTWAVE WILL AID DIURNAL CUMULUS FIELD AND BRING SCT TO BKN LOWER VFR DECK IN THE 5-7KT FOOT RANGE. SCT SHRAS WILL REMAIN EAST OF THE TERMINALS BY AND LARGE. WEST WINDS WILL GUSTS TO 20 KTS CAN BE EXPECTED INTO 00Z-01Z TIME FRAME. GUSTY SW FLOW WILL SET UP BY MIDDAY SUNDAY AS GRADIENT TIGHTENS IN ADVANCE OF APPROACHING COLD FRONT. GUSTS MAY REACH/TOP 25 KNOTS AT TIMES BY AFTERNOON. FOR DTW...SCT-BKN CUMULUS FIELD AT 5KFT MAY TEND TO LIFT TO 6-7KFT AS AFTERNOON PROCEEDS. OTHERWISE...WINDS FROM 270-280 DEGREES WILL GUST TO NEAR 20 KNOTS TODAY WITH 210-220 DEGREE WINDS GUSTING TO 25 KTS OR MORE BY MIDDAY SUNDAY. //DTW THRESHOLD PROBABILITIES... * NONE.
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&& .PREV DISCUSSION...ISSUED 318 AM EDT SAT AUG 1 2015 SHORT TERM...TODAY AND TONIGHT MODIFIED PERSISTENCE FORECAST TODAY AS A WEAK H4 PV ANOMALY EMBEDDED WITHIN CYCLONIC NW FLOW ROTATES THROUGH THE AREA DURING PEAK HEATING. LOWER MOISTURE QUALITY COMPARED TO YESTERDAY WILL LIMIT PROSPECTS FOR SHOWER COVERAGE, BUT ONCE AGAIN EXPECT BEST FORCING AND LAPSE RATES ACROSS THE THUMB. ISOLATED SHOWERS, PERHAPS A CLAP OR TWO OF THUNDER, ALONG WITH ANOTHER AFTERNOON CU UP ARE IN STORE WITH GREATEST COVERAGE OF CLOUDS ACROSS THE NORTH. SLIGHTLY COOLER COLUMN NOTED AS COOLING TAKES PLACE IN THE WAKE OF YESTERDAY`S SHORTWAVE. H85 TEMPS AROUND 11-12C AT 12Z THIS MORNING WILL SUPPORT HIGHS TOPPING OUT NEAR 80 DEGREES. DIMINISHED GRADIENT WILL SUPPORT WLY AFTN GUSTS TOPPING OUT AT ONLY 15-20 KTS. LIMITED COOLING POTENTIAL ONCE AGAIN TONIGHT AS HEIGHTS REBOUND WITH THE PASSAGE OF EMBEDDED SHORTWAVE RIDGE AND LIGHT WARM ADVECTION PERSISTS THROUGH THE OVERNIGHT PERIOD. CIRRUS DEBRIS FROM ANY CONVECTION THAT DEVELOPS UPSTREAM THIS EVENING WILL SPREAD INTO THE AREA BY SUNRISE. NO COMPLAINTS WITH 00Z GUIDANCE OFFERING LOWS AROUND 60. LONG TERM... THE FORECAST FOR THE SECOND HALF OF THE WEEKEND WILL BE INFLUENCED BY THE UPPER LEVEL ENERGY/WAVE COMING OUT OF THE PACIFIC NORTHWEST...WHICH TRACKS THROUGH THE MIDWEST TONIGHT AND THROUGH THE OHIO VALLEY DURING SUNDAY. HOW MUCH MOISTURE WILL THIS WAVE TAKE/DISPLACE TO OUR SOUTH AND EAST? AND HOW MUCH POST WAVE SUBSIDENCE WILL LINGER...AS NORTHERN STREAM UPPER LEVEL TROUGH DIGS SOUTHEAST FROM CENTRAL CANADA AND MAIN COLD FRONT MOVES THROUGH EARLY MONDAY MORNING. GOOD DYNAMICS SUNDAY EVENING/NIGHT...ALONG WITH FAVORABLE LOW LEVEL FGEN/CONVERGENCE SHOULD SUPPORT SHOWERS AND THUNDERSTORMS...EVEN IF THAT LEAD WAVE ROBS MUCH OF THE MOISTURE...AND STILL OK FORECASTING LIKELY POPS FOR SUNDAY EVENING/NIGHT. 00Z NAM INDICATING SURFACE DEW PTS APPROACHING 70 DEGREES...WHICH IS PROBABLY A BIT OF A STRETCH...BUT MID/UPPER 60S WOULD STILL YIELD CAPES AROUND 1500 J/KG...WHICH COULD SUPPORT A FEW SEVERE STORMS WITH THE STRONG WIND FIELDS AND STEEP MID LEVEL LAPSE RATES ADVERTISED (7+ C/KM BETWEEN 700-500 MB). DAY 2 OUT OF SPC INDICATING A SLIGHT CHANCE FOR THE MAJORITY OF SOUTHEAST MICHIGAN. VERY LARGE UPPER LEVEL LOW CENTERED OVER NORTHERN ONTARIO EARLY NEXT WEEK...ALLOWING FOR COOLER TEMPERATURES OVER THE GREAT LAKES REGION AS 850 MB TEMPS FALL INTO THE UPPER SINGLE NUMBERS BY WEDNESDAY. SPOKES OF ENERGY/UPPER LEVEL DISTURBANCES ROTATING AROUND THE PERIPHERY COULD TRIGGER ISOLATED/SCATTERED CONVECTION...BUT UNCERTAINTY ON TIMING AND EXACT POSITION OF THESE FEATURES. MARINE... WESTERLY WINDS TODAY ARE EXPECTED TO BE A BIT LIGHTER COMPARED TO YESTERDAY...WITH STRONGER WINDS FORECASTED TO PEAK OUT AROUND 20 KNOTS. AN APPROACHING COLD FRONT WILL STRENGTHEN THE SOUTHWEST GRADIENT ON SUNDAY HOWEVER...WITH GUSTS AROUND 25 KNOTS LIKELY OVER THE NEARSHORE WATERS. THE COLD FRONT WILL LIKELY TRIGGER STRONG TO SEVERE THUNDERSTORMS SUNDAY EVENING AND NIGHT BEFORE SLIPPING SOUTH THROUGH THE CENTRAL GREAT LAKES MONDAY MORNING. POST FRONTAL NORTHWEST FLOW OVER NORTHERN LAKE HURON LOOKS TO BE IN THE 20 TO 25 KNOT RANGE MONDAY AFTERNOON AND MONDAY NIGHT BEFORE DECREASING SLIGHTLY AS WE HEAD INTO TUESDAY. && .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 MARINE.......SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

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