Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 262310
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
710 PM EDT SUN APR 26 2015

.AVIATION...

DIURNAL CLOUD FIELD IS QUICKLY DIMINISHING...REVEALING THE MOISTURE
STRUCTURE LEFT OVER FOR A COUPLE OF UPPER LEVEL WAVES TO OPERATE ON
THROUGH THE OVERNIGHT HOURS AND EARLY MONDAY. CLOUDS ARE EXPECTED
FILL BACK BY THE MIDNIGHT HOUR IN MOST PLACES THEN PROGRESSIVELY
LOWER DURING THE PRE-DAWN HOURS AS THE CLOUD SHIELD NORTH OF LAKE
HURON ARRIVES.  CEILINGS WILL LIFT THROUGH THE MIDDAY AS THE WAVE
EXITS TO THE SOUTH.  WINDS WILL REMAIN MAINLY FROM THE NORTH.

//DTW THRESHOLD PROBABILITIES...

* HIGH CONFIDENCE IN CIGS BELOW 5000 FT AFTER 10Z TONIGHT.

&&

.PREV DISCUSSION...ISSUED 350 PM EDT SUN APR 26 2015

SHORT TERM...TODAY AND TONIGHT

STEADY WESTWARD EXPANSION OF LOWER HEIGHTS ATTENDANT TO LOW PRESSURE
OVER THE NORTH ATLANTIC LEAVING SE MICHIGAN NOW FIRMLY WITHIN THE
BROAD CYCLONIC WESTERN PERIPHERY.  INCREASING DEPTH TO THE INHERANT
NORTH TO NORTHEAST FLOW SUSTAINING THIS SEASONABLY COOL RESIDENT
ENVIRONMENT...WHILE OPENING THE DOOR FOR A SERIES OF SHORTWAVES OF
ATLANTIC ORIGIN TO PIVOT THROUGH.  LEAD WAVE NOW LIFTING OUT OF THE
STRAITS WILL MOVE ACROSS THE REGION THIS EVENING.  LITTLE BEHIND
THIS IMPULSE TO SUGGEST ANYTHING MORE THAN SOME POCKETS OF THICKER
MID CLOUD...FILLING IN BEHIND A FADING DIURNAL CU FIELD AFTER
SUNSET.

STRONGER PV FILAMENT STILL RESIDING OVER WESTERN QUEBEC THIS
AFTERNOON ARRIVES DURING THE EARLY-MID MORNING HOURS.  BRIEF PERIOD
OF MODERATE CVA AND MOISTURE ADVECTION WILL PROVIDE A DEFINITIVE
INCREASE IN CLOUD COVER DURING THIS TIME.  12Z MODEL GUIDANCE
HOLDING FIRM WITH A LOWER END CHANCE FOR SHOWER DEVELOPMENT WITHIN
THE 06Z-14Z WINDOW...POSITIONING OF THE BETTER FORCING AND MOISTURE
TRANSPORT FAVORING THE THUMB REGION.  LOWS TONIGHT PREDOMINATELY MID
30S.

LONG TERM...MONDAY THROUGH SUNDAY

MODELS IN GOOD AGREEMENT WITH QUIET STRETCH FROM MONDAY THROUGH
WEDNESDAY. IN THE WAKE OF THE OVERNIGHT SHORTWAVE...ENOUGH
SUBSIDENCE TO KEEP OUT ANY CHANCE OF SHOWER DURING MONDAY AFTERNOON.
PLENTY OF MOISTURE UP TO 850 MBS WITH STEEP BOUNDARY LAYER LAPSE
RATES AND CYCLONIC FLOW...EXPECT BKN-OVC STRATOCUMULUS ALL DAY ON
MONDAY. GIVEN THE MOSTLY CLOUDY SKIES AND THE MODELS DEPICTION OF
IT...WILL NOT STRAY FROM THE MOS TEMPS.

SUBSIDENCE INVERSION DEVELOPS MONDAY AFTERNOON AND THIS ALONG WITH
ONE LAST SHORTWAVE ROTATING AROUND THE EAST COAST UPPER LOW...
SHOULD TRAP THE STRATOCU FOR THE BULK OF MONDAY NIGHT.

DRY AIR FINALLY STARTS TO MOVE INTO THE REGION ON TUESDAY AS THE
SURFACE HIGH PUSHES INTO THE NORTHWEST PORTION OF THE GREAT LAKES.
WITH THE 850 MB THERMAL TROF HANGING OVER THE REGION AND DECENT
BOUNDARY LAYER MOISTURE...WILL GO WITH PARTLY SUNNY SKIES FROM THE
DIURNAL CUMULUS. WITH THE PARTLY SUNNY SKIES AND SLIGHTLY DRIER
BOUNDARY LAYER...WILL LEAN TOWARD THE HIGHER GUIDANCE NUMBERS FOR
HIGH TEMPS ALTHOUGH AN EASTERLY COMPONENT WILL KEEP THE LAKE SHORES
A LITTLE COOLER. EXPECT THE DIURNAL CU TO DISSIPATE TUESDAY EVENING
FOR A CLEAR NIGHT.

ONLY EXPECT SCATTERED CU ON WEDNESDAY WITH THE SURFACE HIGH AND
DRIER AIR FULLY ENTRENCHED OVER THE GREAT LAKES.  ANOTHER WAVE
PASSING TO WELL NORTH OF THE FORECAST AREA MAY GENERATE ENOUGH CI TO
BRING PARTLY SUNNY SKIES FOR THE NORTHERN PORTIONS OF THE FORECAST
AREA. THE COMBINATION OF MORE SUN AND 850 MB TEMPS WARMING SEVERAL
DEGREES WILL LEAD TO HIGH TEMPS ON WEDNESDAY FROM AROUND 60 TO THE
MID 60S.

12Z GFS/ECMWF HAVE CONTINUED THE IDEA OF ENERGY MOVING NEARLY DUE
SOUTH ACROSS LAKE HURON THURSDAY...SO FORECAST CONTINUES TO FAVOR A
COOLER SOLUTION. THOUGH A FEW SHOWERS ARE POSSIBLE WITH THIS
PROCESS...QUESTIONABLE MOISTURE WARRANTS MAINTAINING DRY FORECAST.
THIS POCKET OF COLD AIR LOOKS TO BE TRANSIENT WITH RISING HEIGHTS
FRIDAY INTO THE WEEKEND LEADING TO A SOLID WARMING TREND. MAINLY DRY
FORECAST FAVORED ATTM DUE TO ANTECEDENT DRY AIRMASS...THOUGH SOME
SOLUTIONS HINT AT A MORE CONCERTED MOISTURE INCREASE DURING LATTER
HALF OF THE WEEKEND...SO INTRODUCED LOW CHANCE POPS BY SUNDAY.

MARINE...

PERSISTENT LOW PRESSURE ALONG THE EAST COAST AND STRENGTHENING HIGH
PRESSURE BUILDING ACROSS THE WESTERN GREAT LAKES TONIGHT WILL
CONTINUE TO STRENGTHEN THE N-NW GRADIENT ACROSS LAKES HURON AND ERIE
TONIGHT. THE NET RESULT WILL BE A STRENGTHENING OF THE N-NW WINDS
THROUGH TONIGHT. WINDS AND WAVES WILL THEN SLOWLY DECREASE MONDAY
INTO TUESDAY MORNING AS HIGH PRESSURE BUILDS INTO THE REGION FROM
THE WEST. THE LIGHTER WINDS AND WAVES WILL CONTINUE INTO WEDNESDAY
AS HIGH PRESSURE REMAINS OVER THE GREAT LAKES.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR LHZ421-441>443.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MANN
SHORT TERM...MR
LONG TERM....RBP/DT
MARINE.......RBP


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