Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 280350
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1150 PM EDT FRI MAR 27 2015


.AVIATION...

IT APPEARS ONE LAST SURGE OF LOW LEVEL CLOUDS WILL PIVOT DOWN INTO
THE TERMINALS FROM LAKE HURON WITHIN NORTHEAST FLOW OF 5 TO 10
KNOTS. THIS WILL BRING A PERIOD OF LOWER VFR CIGS FROM KFNT ON
SOUTH. EXPECT CLEARING ON SATURDAY AS HIGH PRESSURE BUILDS INTO THE
AREA WITH WINDS BACKING TO NORTHWEST AND THEN BECOMING LIGHT AND
VARIABLE BY SATURDAY EVENING AS THE CENTER OF THIS HIGH REACHES THE
AREA.

FOR DTW...GENERALLY EXPECT FEW-SCT VFR CONDITIONS...BUT THERE WILL
BE A CHANCE OF A SEVERAL HOUR PERIOD OF BKN CIGS AROUND 5KFT LATE
TONIGHT AS MOISTURE FUNNELS INTO AREA FROM THE THUMB.


//DTW THRESHOLD PROBABILITIES...

* LOW CONFIDENCE IN CEILINGS AROUND 5000 FT THROUGH LATE TONIGHT
  INTO EARLY SATURDAY MORNING.

&&

.PREV DISCUSSION...ISSUED 340 PM EDT FRI MAR 27 2015

SHORT TERM...TONIGHT

GOOD SUBSIDENCE AND DRYING OCCURRING BEHIND UPPER LEVEL TROUGH AXIS
MOVING THROUGH THE CENTRAL GREAT LAKES THIS AFTERNOON...WITH SURFACE
DEW PTS PLUNGING TO AROUND ZERO OVER CENTRAL SECTIONS OF THE
STATE...UNDER MOSTLY CLEAR SKIES. CLOUDS HAVE THINNED OUT OVER
SOUTHEAST MICHIGAN...BUT COLD (NEGATIVE UPPER TEENS AT 850 MB)
NORTHERLY FLOW OFF LAKE HURON IS MAINTAINING JUST ENOUGH MOISTURE TO
MAINTAIN MOSTLY CLOUDY SKIES AND EMBEDDED SNOW SHOWERS. THE ACTIVITY
IS VERY DISORGANIZED...BUT STEEP LOW LEVEL LAPSE RATES HAVE PRODUCED
VERY SMALL INTENSE CELLS...DROPPING VSYBS BRIEFLY BELOW 1 MILE IN
ISOLATED SPOTS. WITH HIGH PRESSURE BUILDING OVER THE WESTERN GREAT
LAKES TONIGHT...THE DRIER AIR/CLEAR SKIES SHOULD CONTINUE TO BLEED
INTO SOUTHEAST MICHIGAN...BUT PROBABLY STRUGGLE TO ADVANCE MUCH PAST
U.S. 23. LONG FETCHED NORTHERLY FLOW AND LOW LEVEL CONVERGENCE
FORECASTED BY 12Z NAM OVER THUMB REGION THIS EVENING SHOULD
MAINTAIN...OR ALLOW FOR REDEVELOPMENT OF ACTIVITY. STILL...THE
OVERALL DRY ENVIRONMENT AND LOW INVERSION HEIGHTS WILL TEMPER
ACTIVITY...AND EXPECTING A VERY NARROW BAND WITH SOME MOVEMENT...AND
THUS ANTICIPATING ACCUMULATIONS BELOW 1 INCH.

WITH TEMPERATURES STILL HOLDING THE 20S THIS AFTERNOON...MINS IN THE
LOW TO MID TEENS SHOULD BE NO PROBLEM...WITH THE POTENTIAL FOR
SINGLE NUMBERS IF THAT CLEARING LINE ADVANCES EAST OVERNIGHT. RECORD
LOWS FOR MARCH 28TH ARE GENERALLY IN THE LOWER SINGLE NUMBERS AND
ARE LIKELY OUT OF REACH AS WINDS WILL PROBABLY NOT GO CALM EVEN IF
WE DO TOTALLY CLEAR OUT.

LONG TERM...

LONGWAVE TROUGH CURRENTLY CENTERED NEAR MICHIGAN AND INDIANA WILL
COMPACT AND MOVE EASTWARD...LEADING TO A 500MB HEIGHT RECOVERY
SUNDAY THROUGH THE EXTENDED PERIOD. SATURDAY WILL CONTINUE TO BE
WELL BELOW NORMAL AS THE H85 TEMP FIELD REMAINS IN THE NEGATIVE
TEENS C. EXPECTING MAXES IN THE MID 30S. DESPITE THESE LOW
VALUES...ANTICYCLONE DIRECTLY OVERHEAD WILL PROVIDE A LIGHT WIND
FIELD AND FULL SUN.  ADDING LATE MARCH INSOLATION...CONDITIONS MAY
NOT FEEL TOO BAD.

ONCE THE SURFACE HIGH MOVES SOUTHEAST OF THE CWA ON
SUNDAY...SOUTHWEST WINDS OF 40-50KT AT H85 WILL QUICKLY USHER IN
WARMER TEMPERATURES. THIS LLJ WILL ALSO ACT TO INCREASE MOISTURE
CONTENT (3-4G/KG) TO AN APPROACHING COLD FRONT. THE WAVE ORIGINATES
WITH PACIFIC MOISTURE AND TRANSLATES ACROSS A CONTINENTAL AIRMASS
BEFORE BEING REINFORCED WITH GOM MOISTURE ON SUNDAY. TOUGH CALL ON
PRECIP TYPE WITH THIS SYSTEM AS TOP-DOWN IT FAVORS A COLD CANADIAN
TEMP PROFILE. SURFACE TO H7 HOWEVER...IT SEEMS THE WAA IS TAKING
OVER AND SURFACE TEMPS SHOULD BE AROUND +1C. WHILE THERE IS A CHANCE
THAT RAIN/SNOW MIX OR A 35F SNOW COULD OCCUR...FAVORING THE WARMER
SIDE OF GUIDANCE THAT INDICATES ABOVE FREEZING TEMPS IN THE BOUNDARY
LAYER (FIRST 1500+ FEET). FORECAST THEREFORE CALLING FOR A COLD 0.2
INCH RAIN EVENT SUNDAY AFTERNOON-EVENING.

BRIEF RIDGING ON MONDAY WILL ALLOW FOR DRY CONDITIONS TO PERSIST
ACROSS SOUTHEAST MICHIGAN FOR THE BEGINNING OF NEXT WEEK. ACTIVE
WEATHER QUICKLY RETURNS THOUGH ON MONDAY NIGHT AS A CLIPPER SYSTEM
ROLLS THROUGH THE REGION. TEMPERATURES LOOK TO BE COLD ENOUGH AT
THIS TIME TO SUPPORT ALL SNOW...WHICH COULD RESULT IN A HALF INCH OF
SNOW AT THE VERY LEAST...MAINLY NORTH OF THE M-59 CORRIDOR. THERE IS
STILL SOME DISAGREEMENT IN THE TRACK OF THIS SYSTEM THOUGH...SO
PRECIP TYPE AND AMOUNT IS NOT COMPLETELY CERTAIN. WARMER
TEMPERATURES AND DRY CONDITIONS RETURN ON WEDNESDAY AND LAST INTO
THURSDAY...WHEN THE NEXT POTENTIAL RAIN MAKER ARRIVES.

MARINE...

NORTH WINDS WILL BE SLOW TO RELAX OVER LAKE HURON TONIGHT AS ISOBARS
SPREAD OUT SOME DUE TO INCOMING HIGH PRESSURE. THE LAKE REMAINS
ACTIVE WITH UPPER LEVEL TEMPS STILL VERY COLD (H85 AT -13C)...WHICH
ADDS TO THE HIGHER WINDS OVER THE WATER. LOOK FOR HIGH WAVES
ESPECIALLY NEAR THE THUMB REGION AS THE NORTH FETCH IS FAVORABLE FOR
AMPLIFICATION. WINDS RAMP BACK UP SUNDAY WITH SOME GUSTS TO GALES AS
990MB LOW MOVES JUST NORTH OF THE REGION. SOUTHWEST WINDS WILL USHER
IN WARMER AIR...SO NOT EXPECTING LAKES TO BECOME UNSTABLE.

&&

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

$$

AVIATION.....DG
SHORT TERM...SF
LONG TERM....MM/RK
MARINE.......MM


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