Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
701
FXUS63 KDTX 250348
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1148 PM EDT SUN APR 24 2016


.AVIATION...

VFR CONDITIONS HOLD FIRM THROUGH MIDDAY MONDAY WITH SIMPLY AN MORE
EXTENSIVE/THICKER MID CLOUD DURING THIS TIME.  MBS WILL REMAIN
WITHIN THE SOUTHERN FRINGE OF A FRONTAL BOUNDARY...LEAVING THIS
CORRIDOR SUSCEPTIBLE TO BRIEF/LIGHT POCKETS OF RAIN INTO TONIGHT.
EAST TO NORTHEAST WIND THIS EVENING WILL EASE AND GENERALLY VEER TO
SOUTHEASTERLY BY MONDAY MORNING.  INCREASINGLY MOIST/UNSTABLE
ENVIRONMENT WILL THEN BRING POTENTIAL SHOWERS/THUNDERSTORMS LATE
MONDAY INTO MONDAY NIGHT.  CONSIDERABLE UNCERTAINTY YET IN BOTH
TIMING AND COVERAGE OF CONVECTION DURING THIS TIME.  GREATEST WINDOW
SEEMINGLY FROM LATE EVENING INTO EARLY MONDAY NIGHT...CURRENT
FORECAST FAVORS AN OCCURRENCE AFTER 00Z.

FOR DTW...CLEAR SKIES WITHIN THE LOWEST 5K FT THROUGH MID DAY
MONDAY.  MODEST EAST TO SOUTHEAST FLOW DURING THIS TIME.  EMERGING
WELL MIXED AND SUBSEQUENTLY GUSTY SOUTH TO SSW WIND BEHIND A WARM
FRONT INTO THE AFTERNOON.  WINDOW FOR SHRA/TSRA GREATEST FROM LATE
EVENING INTO EARLY MONDAY NIGHT /AFTER 00Z/...AND WILL HOLD FIRM
WITH A DRY FORECAST WITH AN INCREASE IN HIGH BASED CU /6K FT/ FOR
THE AFTERNOON PERIOD.

//DTW THRESHOLD PROBABILITIES...

* LOW IN OCCURRENCE AND POSSIBLE TIMING OF THUNDERSTORMS MONDAY
  AFTERNOON THROUGH MONDAY NIGHT.

&&

.PREV DISCUSSION...ISSUED 315 PM EDT SUN APR 24 2016

DISCUSSION...

A STRONGLY CONFLUENT MID LEVEL FLOW IS IN PLACE ACROSS THE GREAT
LAKES REGION TO THE SOUTH OF A HUDSON BAY POLAR LOW. MEANWHILE...
SATELLITE DATA INDICATES AN INFLUX OF LOW-MID LEVEL MOISTURE INTO
THE UPPER MS VALLEY/WRN GREAT LAKES IN ADVANCE OF A CLOSED MID LEVEL
LOW NOW OVER THE NRN HIGH PLAINS. THE ASSOC SFC LOW OVER SD HAS A
QUASI STATIONARY FRONT EXTENDING INTO NRN LOWER MI. THERE IS A
NOTABLE THERMAL GRADIENT ALONG THIS FRONT AS SOUTHERLY FLOW ADVECTS
VERY MILD AIR ACROSS THE WARM SECTOR...WHILE THE CIRCULATION AROUND
THE CENTRAL CANADA SFC HIGH IS MAINTAINING COLD CONDITIONS TO THE
NORTH. THE INFLUX OF HIGHER THETA E AIR INTO THE WESTERN GREAT LAKES
HAS RESULTED IN SOME SHOWERS MOVING INTO CNTL MI THIS AFTERNOON.
THE UPPER LOW ACROSS THE PLAINS WILL BE FORCED EASTWARD TONIGHT.
THERE IS ALSO ONGOING STRENGTHENING OF AN UPPER JET MAX TO THE
NORTHEAST OF LOWER MI. THESE TWO FACTORS WILL SUPPORT INCREASING
FRONTOGENESIS IN THE MID LEVELS ALONG/NORTH OF THE SFC FRONT THIS
EVENING INTO THE OVERNIGHT. THE FORCING WILL LARGELY REMAIN FOCUSED
ACROSS NRN LOWER MI. CONTINUED MID LEVEL THETA E ADVECTION DURING
THE COURSE OF THE NIGHT AND THE CLOSER PROXIMITY TO THE MID LEVEL
FGEN CONTINUES TO SUPPORT A GOOD CHANCE OF SHOWERS ACROSS THE
SAGINAW VALLEY/THUMB THIS EVENING AND TONIGHT. FARTHER
SOUTH...INCREASING MID LEVEL CLOUDS WITH ISOLATED LIGHT
SHOWERS/SPRINKLES IS ALL THAT IS EXPECTED.

CONTINUED AGREEMENT IS SHOWN AMONG THE MODEL SUITE THAT THE CLOSED
MID LEVEL LOW NOW OVER THE PLAINS WILL RAPIDLY DAMPEN/SHEAR APART AS
IT ENTERS THE CONFLUENCE ACROSS THE GREAT LAKES. THE REMNANT WAVE IS
FORECAST TO TRAVERSE LOWER MI LATE MON NIGHT/TUES MORNING...WITH THE
ASSOCIATED SURFACE LOW TRACKING ALONG THE QUASI STATIONARY FRONT
OVER SRN LOWER MI LATE MON NIGHT. THERE IS STILL SOME DISAGREEMENT
AMONG MODEL SOLUTIONS AS TO PLACEMENT OF THE SFC FRONT ON MONDAY.
THE EASTWARD ADVANCEMENT OF THE UPSTREAM UPPER LOW IS SHOWN TO
INVOKE SOME SHORT WAVE RIDGING DOWNSTREAM ACROSS LOWER MI LATE
TONIGHT INTO EARLY MON AFTERNOON.MODEL SOUNDINGS SUGGEST THIS WILL
DEVELOP A MID LEVEL CAPPING INVERSION AND SUPPRESS PRECIP THROUGH
THE FIRST HALF OF THE DAY. THIS WILL SUPPORT A WELL MIXED FLOW IN
THE WARM SECTOR AND WILL LIKELY HOLD THE FRONT UP NEAR LAKE HURON
THROUGH EARLY MON AFTERNOON. WELL MIXED CONDITIONS SOUTH OF THE
FRONT WITH 925MB TEMPS FORECAST TO PUSH +19C WILL SUPPORT HIGHS WELL
INTO THE 70S. TEMPS ON THE COLD SIDE OF THE FRONT /WHERE THE AIR
WILL HAVE LAKE HURON MODIFICATION/ WILL BE IN THE 40S AND 50S. THIS
FRONT IS FORECAST TO NUDGE SOUTHWARD ACROSS THE SAGINAW VALLEY/THUMB
LATE MONDAY...WHICH WOULD RESULT IN A SUBSTANTIAL LATE DAY DROP IN
TEMPS IN THESE LOCALS.

MODEL SOUNDINGS CONTINUE TO SUGGEST MODEST DAYTIME DESTABILIZATION
WILL LEAD TO SB CAPE APPROACHING 1K J/KG. SOME SEMBLANCE OF A CAP
SHOULD HOLD OFF ON CONVECTIVE INITIATION UNTIL LATE IN THE DAY WHEN
MID LEVEL HEIGHT FALLS BEGIN TO OVERSPREAD THE REGION FROM THE WEST.
THE APPROACH OF THE UPPER WAVE AND ENHANCED LOW LEVEL CONVERGENCE
ASSOCIATED WITH THE SFC LOW WILL SUPPORT BETTER CHANCES FOR
CONVECTION MON NIGHT. ADVECTION OF HIGHER LOW LEVEL MOISTURE MON
NIGHT WITH RELATIVELY STEEP MID LEVEL LAPSE RATES WILL SUSTAIN A
GOOD DEAL OF ELEVATED INSTABILITY /SHOWALTER OF -2 TO -4 C/ MON
NIGHT. THIS INSTABILITY COMBINED WITH 0-6KM SHEAR ON THE ORDER OF 25
TO 40 KNOTS SUGGESTS A CHANCE OF SOME STRONG TO SEVERE CONVECTION
LATE MON THROUGH MON NIGHT. THE PASSAGE OF THE SFC LOW TO THE EAST
TUESDAY MORNING WILL DRIVE THE COLD FRONT SOUTH OF THE STATE BY TUES
AFTERNOON. LINGERING LOW LEVEL MOISTURE UNDER A DEEPENING LOW LEVEL
INVERSION WILL LIKELY SUSTAIN AN ABUNDANCE OF LOW CLOUDS TUES WHILE
PERSISTENT NORTHEAST WINDS OFF LAKE HURON AID IN HOLDING SFC TEMPS
DOWN. THIS WILL SUPPORT FAIRLY COLD TEMPS TUES AFTERNOON/TUES NIGHT.
THE DEGREE OF LOW LEVEL MOISTURE...WITH DRYING ATOP THE MOIST LAYER
AND GOOD SHEAR WITHIN THE INVERSION ALSO SUGGESTS SOME POTENTIAL FOR
DRIZZLE DURING THE DAY TUESDAY.

HIGH PRESSURE WILL REMAIN OVER THE GREAT LAKES REGION ON WEDNESDAY
KEEPING CONDITIONS DRY AND COOL. CLOUDS BUILD INTO THE REGION ON
WEDNESDAY AFTERNOON AS THE NEXT LOW PRESSURE SYSTEM APPROACHES FROM
THE WEST. WHILE THE CENTER OF THIS LOW WILL REMAIN SOUTH OF THE OHIO
BORDER...RAIN SHOWERS ARE EXPECTED ACROSS SOUTHEAST MICHIGAN ON
THURSDAY. AN ISOLATED THUNDERSTORM IS ALSO POSSIBLE ACROSS THE
SOUTHERN CWA ON THURSDAY AFTERNOON AS BETTER INSTABILITY WORKS INTO
THE AREA. STRONG HIGH PRESSURE BUILDS SOUTHWARD OUT OF NORTHERN
CANADA ON FRIDAY AND REMAINS SITUATED OVER THE REGION FOR THE FIRST
HALF OF NEXT WEEKEND.

MARINE...

A FRONT WILL SETTLE OVER LAKE HURON ON MONDAY LEADING TO FRESH EAST
NORTHEAST WINDS OVER THE NORTHERN BASIN AND MODERATE SOUTHEAST WINDS
TO THE SOUTH IN ADDITION TO A WIDESPREAD CHANCE OF THUNDERSTORMS.
FRESH NE WIND WILL THEN FILL IN ACROSS ALL AREA WATERS LATE MONDAY
AFTERNOON INTO TUESDAY. SMALL CRAFT ADVISORIES MAY BE NEEDED FOR THE
NEARSHORE WATERS OF LAKE HURON FOR WINDS AS WELL AS WAVES DUE TO
PERSISTENT ONSHORE FLOW DURING THIS TIME. THERE IS A SMALL CHANCE
THAT WIND GUSTS MONDAY NIGHT INTO TUESDAY MORNING MAY REACH GALE
FORCE. CONFIDENCE THAT TIMING OF ANY GALES WILL REACH THREE HOURS IS
LOW...SO A GALE WATCH WILL NOT BE ISSUED ATTM. HIGH PRESSURE WILL
BRING DIMINISHING WINDS THROUGH MIDWEEK.

HYDROLOGY...

LOW PRESSURE AND ATTENDANT COLD FRONT WILL MOVE THROUGH SOUTHEAST
MICHIGAN MONDAY THROUGH MONDAY NIGHT. SHOWERS AND EMBEDDED
THUNDERSTORMS ARE CURRENTLY FORECAST TO PRODUCE AROUND ONE HALF TO
THREE QUARTERS OF AN INCH OF RAIN MONDAY THROUGH TUESDAY MORNING.
THE BULK OF THE RAIN IS FORECAST BETWEEN 00-06Z MONDAY NIGHT.
THUNDERSTORMS WILL POTENTIALLY PRODUCE LOCALLY HIGHER AMOUNTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 5 PM MONDAY TO 10 PM EDT TUESDAY FOR
     LHZ421-441>443.

     SMALL CRAFT ADVISORY FROM 11 PM MONDAY TO 10 PM EDT TUESDAY FOR
     LHZ422.

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

$$

AVIATION.....MR
DISCUSSION...SC/RK
MARINE.......JVC
HYDROLOGY....JVC


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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.