Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 021723
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
123 PM EDT SAT MAY 2 2015


.AVIATION...

HIGH PRESSURE AND A DRY COLUMN WILL MAINTAIN MOSTLY CLEAR SKIES
THROUGH TONIGHT. FEW-SCT COVERAGE OF HIGH BASED CU WILL BE POSSIBLE
THIS AFTERNOON. LIGHT WESTERLY WINDS WILL BACK TO SOUTHWESTERLY
TOWARD MORNING.

//DTW THRESHOLD PROBABILITIES...

* NONE.

&&

.PREV DISCUSSION...ISSUED 349 AM EDT SAT MAY 2 2015

SHORT TERM...TODAY AND TONIGHT

SHEARING UPPER SHORTWAVE WILL CONTINUE TO WORK ACROSS MICHIGAN EARLY
TODAY...PUSHING AN AREA OF HIGH CLOUDS ACROSS THE AREA. THIS WILL
LEAD TO OVERALL PARTLY CLOUDY SKIES AS SOME CU ALSO DEVELOPS WITH
DAYTIME HEATING. THE WAVE WILL EXIT EAST LATE THIS AFTERNOON
TODAY...ALLOWING SHORTWAVE RIDGING ALOFT TO BUILD IN BEHIND IT
TONIGHT.

AT THE SURFACE...HIGH PRESSURE WILL BE CENTERED NEAR KY/TN. THIS
WILL PROVIDE A LIGHT WESTERLY GRADIENT TODAY AS MICHIGAN REMAINS ON
THE NORTHERN PERIPHERY OF THIS HIGH. WITH SOME CLOUDS WORKING ACROSS
THE AREA AND OVERALL DECENT PERFORMANCE OF GUIDANCE VALUES
YESTERDAY...FORECAST HIGHS CLOSE TO MOS IN THE LOW TO MID 70S LOOK
GOOD. THESE ARE JUST SLIGHTLY WARMER THAN YESTERDAY...AND CORRESPOND
WELL TO A SLIGHT INCREASE IN 925MB/850MB TEMPS AND A WARMER START TO
THE DAY.

QUIET CONDITIONS ARE EXPECTED OVERNIGHT WITH FORECAST LOWS IN THE
MID 40S TO NEAR 50 LOOKING APPROPRIATE AS WE SEE LIGHT WINDS AND
SOME BREAKS IN THE HIGH CLOUDS.

LONG TERM... SUNDAY THROUGH THURSDAY

SUNDAY WILL START OUT WITH SE MICHIGAN REMAINING UNDER LINGERING
INFLUENCE OF HIGH PRESSURE CENTERED ALONG THE ATLANTIC COAST AND SE
STATES. IT WILL BE A WARM DAY BY EARLY MAY STANDARDS...ESPECIALLY AS
SOUTHWEST WIND INCREASES DURING THE DAY AHEAD OF THE NEXT COLD FRONT
ARRIVING IN CENTRAL CANADA AND THE MIDWEST DURING THE AFTERNOON. MAX
TEMPS WILL MAKE A RUN AT 80 DEPENDING ON HOW MUCH AND WHEN CLOUD
COVER CAN IMPACT SURFACE HEATING. THE 00Z MODEL RUNS ARE IN GOOD
AGREEMENT WITH THE DEPICTION OF A MID LEVEL THETA-E RIDGE DEVELOPING
AHEAD OF THE FRONT AND SLIDING INTO LOWER MICHIGAN IN THE 700-500 MB
LEVEL DURING THE AFTERNOON. THIS TIMING WILL LIKELY GIVE EARLY DAY
SUNSHINE A CHANCE TO DO ALL IT NEEDS TO GIVE TEMPS THE NECESSARY
LIFT FOR AT LEAST UPPER 70S. AS FOR PRECIP...THE GFS LOOKS TOO
GENEROUS WITH LIGHT QPF OVER THE REGION DURING THE AFTERNOON. MODEL
SOUNDINGS...INCLUDING THE GFS...HAVE THE BOUNDARY LAYER MIXED TO
NEAR 800 MB WITH ENOUGH DRY AIR TO EAT AWAY AT ANY RAIN THAT MAY
DEVELOP FROM THE HIGH BASED AND SHALLOW CLOUD LAYER.

THE WARM SUNDAY CONDITIONS WILL LEAD INTO A MILD SUNDAY NIGHT PERIOD
AS LOW LEVEL MOISTURE CONTINUES TO INCREASE AHEAD OF THE FRONT.
SOUTHWEST WIND AT 10 TO 15 KNOTS WILL BOOST SURFACE DEWPOINT INTO
THE MID 50S WHICH...COMBINED WITH INCREASING CLOUDS...WILL PREVENT
TEMPS FROM FALLING BACK MUCH COOLER THAN 60 DURING THE NIGHT.
SHOWERS WILL ALSO BECOME LIKELY LATE IN THE NIGHT MAINLY IN THE TRI
CITIES BASED ON MODEL CONSENSUS ON TIMING OF THE PREFRONTAL MOISTURE
AXIS AND QPF FIELDS. THERE COULD BE A RUMBLE OF THUNDER BUT THIS
ACTIVITY WILL BE ON A DOWNWARD INTENSITY TREND AT THE DIURNAL
MINIMUM WITH INSTABILITY BEING ELEVATED AND DRIVEN LARGELY BY LOW
LEVEL MOISTURE ADVECTION. THE NAM REMAINS TAME ON FORECAST 700-500
MB LAPSE RATES IN THE 5-6 C/KM RANGE WITH SURFACE BASED INSTABILITY
APPROACHING 1000 J/KG EVEN DURING MONDAY AFTERNOON OVER SE MICHIGAN
AHEAD OF THE FRONT. THESE NUMBERS MAY BE ON THE LOW SIDE COMPARED TO
THE GFS FOR A FRONTAL PASSAGE DURING PEAK HEATING...BUT OUR AREA
WILL ALSO BE ON THE SOUTHERN FRINGE OF THE COLD POOL ALOFT
ASSOCIATED WITH THE WAVE WELL NORTH OVER QUEBEC BY MONDAY
EVENING...STILL GOOD ENOUGH FOR ORDINARY THUNDERSTORMS EMBEDDED
WITHIN THE LARGER PATTERN OF SHOWERS AS THE FRONT SLIDES THROUGH THE
REGION.

THE GENERAL TREND FOR THE MID WEEK PERIOD REMAINS INTACT AND
CONTINUES TO CALL FOR THE FRONT TO STALL NEAR THE OHIO BORDER MONDAY
NIGHT THROUGH TUESDAY. THE LATEST MODEL SOLUTIONS ARE SIMILAR TO THE
LAST FEW CYCLES IN THIS REGARD. THE ECMWF DRIVES THE FRONT A LITTLE
FARTHER SOUTH...MAYBE TOO FAR CONSIDERING HOW MUCH THE UPPER RIDGE
IS SHOWN TO BUILD OVER THE MIDWEST TUESDAY INTO WEDNESDAY. CHANCE
POPS ARE MAINTAINED AS THE FRONTAL REMNANTS RETURN NORTHWARD
WEDNESDAY AS A DISORGANIZED WARM FRONT TIED TO THE UPPER LEVEL RIDGE
AXIS. PROGRESSION OF THE RIDGE TO OUR EAST WILL OPEN THE DOOR ON
CONTINUED ABOVE NORMAL TEMPERATURES THROUGH NEXT WEEK.

MARINE...

MARINE CONDITIONS WILL REMAIN FAVORABLE THROUGH THE REMAINDER OF THE
WEEKEND CONSISTING OF DRY WEATHER AND WARM TEMPERATURES. THERE WILL
BE AN UPTICK IN WIND DURING SUNDAY BUT STABILITY WILL BE HIGH OVER
THE OPEN WATERS WHICH WILL LIMIT WAVE GROWTH. THE NEXT COLD FRONT
WILL SLIDE THROUGH LAKE HURON AND LOWER MICHIGAN LATE SUNDAY NIGHT
AND MONDAY...AND THEN STALL NEAR THE OHIO BORDER TUESDAY. SHOWERS
AND THUNDERSTORMS ARE LIKELY DURING THIS TIME...BUT MOST OF THE
ACTIVITY WILL FOCUS OVER THE SOUTHERN LAKE HURON BASIN AND SOUTHWARD
INTO LAKE ERIE AFTER THE FRONTAL PASSAGE MONDAY.

&&

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

$$

AVIATION.....JVC
SHORT TERM...HLO
LONG TERM....BT
MARINE.......BT


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



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