000
FXUS63 KDTX 151924
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
324 PM EDT TUE APR 15 2014

.SHORT TERM... TODAY AND TONIGHT

BOUNDARY LAYER GROWTH AND MOISTURE FLUX OFF THE LAKES HAS
CONTRIBUTED TO WIDESPREAD CLOUD COVER AND SNOW SHOWERS/FLURRIES
THROUGHOUT THE AFTERNOON. THE HEIGHT FIELD HAS BEGUN TO REBOUND ACROSS
THE REGION IN RESPONSE TO AN APPROACHING SHORTWAVE THAT WILL LIFT
TOWARD IA/MN WEDNESDAY MORNING. THE RESULTANT PATTERN OF WARM
ADVECTION WILL ALLOW TEMPERATURES ALOFT TO WARM A BIT OVERNIGHT, BUT
THE SURFACE GRADIENT WILL BE WEAK AND EARLY DECOUPLING IS FAVORED AS
SKIES CLEAR UNDER THE INFLUENCE OF BUILDING HIGH PRESSURE AND
NOCTURNAL STABILIZATION. CONTINUED MENTION OF FLURRIES THROUGH 8PM
WITH POORLY ORGANIZED CELLULAR TYPE CONVECTION, BUT REMOVED POPS AS
MEASURABLE POTENTIAL APPEARS TO BE NIL FROM HERE ON OUT WITH LOSS
OF BANDING AND DECREASING INSTABILITY. LOWS WILL PLUMMET UNDER WHAT
REMAINS OF SNOW COVER, CALM WINDS, AND MOSTLY CLEAR SKIES. RECORD OR
NEAR-RECORD LOWS IN THE TEENS TO AROUND 20 ARE LIKELY (SEE CLIMATE
SECTION).

&&

.LONG TERM...WEDNESDAY THROUGH NEXT TUESDAY

AN UPPER LEVEL WAVE...CURRENTLY VISIBLE OVER THE PACIFIC NORTHWEST
ON WATER VAPOR IMAGERY...WILL EMERGE OVER THE NORTHERN PLAINS ON
WEDNESDAY AND OVER THE WESTERN GREAT LAKES WEDNESDAY NIGHT. THIS
WAVE WILL BRING A BAROCLINIC ZONE THROUGH THE GREAT LAKES REGION ON
THURSDAY...HALTING OVER THE CENTRAL GREAT LAKES AS THE MAIN WAVE
TAKES A TURN NORTHEAST TOWARDS JAMES BAY. THIS BAROCLINIC ZONE WILL
WEAKEN AS THE MAIN ENERGY EJECTS NORTHEAST AND HALT ITS EASTWARD
PROGRESS...KEEPING SOUTHEAST MICHIGAN ON THE DRY SIDE OF THIS
BOUNDARY. TEMPERATURES ARE EXPECTED TO RISE TO AROUND 60 AHEAD OF
THIS BOUNDARY ON THURSDAY WITH MODERATE WARM AIR ADVECTION AS LOW
LEVEL WINDS TURN SOUTHERLY.

A BETTER DEFINED TROUGH TRACKING ACROSS THE NORTHERN CONUS WILL PUSH
THE AFOREMENTIONED BOUNDARY THROUGH THE CENTRAL GREAT LAKES THURSDAY
NIGHT AND FRIDAY ON ITS WAY TO THE EAST COAST. THERE ARE STILL
SUBSTANTIAL TIMING ISSUES AMONGST THE NWP MODELS REGARGING THE
TIMING OF THIS BOUNDARY...WHICH HAS IMPLICATIONS ON FRIDAYS HIGH
TEMPERATURES AS A SOONER FROPA WOULD MEAN LOWER HIGH TEMPERATURES
AND A SOONER CHANGEOVER TO WET SNOW AS COLDER AIR FILTERS IN FROM
THE NORTH. STILL FAVOR THE PHASED SOLUTION PRESENTED BY THE GFS
WHICH WOULD SUPPORT RAIN FRIDAY CHANGING OVER TO WET SNOW FRIDAY
NIGHT WITH A SLOWER FROPA.

THE MAIN FEATURE FOR THIS WEEKEND WILL BE THE BATTLE BETWEEN A
SPRAWLING AREA OF HIGH SURFACE PRESSURE VS A STRUNG OUT FRONTAL
BOUNDARY ACROSS THE REGION. NWP GUIDANCE HAS DIFFERING VIEWS OF THE
STRENGTH OF THE SURFACE PRESSURE /ECMWF 4 HPA HIGHER THAN GFS/.
EVEN IF THE SURFACE LOW AND ASSOCIATED FRONT GAIN MORE UPPER LEVEL
SUPPORT...THE ONSET OF RAIN SHOULD HOLD OFF UNTIL THE AFTERNOON
HOURS OF EASTER. TIMING OF RAIN/EXIT OF THE COLD FRONT ON MONDAY IS
OUT OF PHASE IN THE MODELS...SO A CHANCE POP REMAINS IN THE FORECAST
FOR SEVERAL PERIODS DESPITE THE LIKELY SHORT PRECIP WINDOW.

&&

.MARINE...

NORTHWEST WINDS OF 20 TO 30 KNOTS LATE THIS AFTERNOON WILL DIMINISH
RAPIDLY THIS EVENING. SIGNIFICANT WAVE HEIGHTS WILL BUILD TO 7 FEET
OR HIGHER OVER THE OPEN WATERS OF CENTRAL LAKE HURON AND WILL BE IN
EXCESS OF 4 FEET ALONG THE EXPOSED NEARSHORE WATERS OF THE THUMB.
THIS IN COMBINATION WITH FREQUENT GUSTS OF 25 KNOTS SUPPORTS
CONTINUANCE OF THE SMALL CRAFT ADVISORIES FOR LAKE HURON THROUGH THE
EVENING HOURS. WINDS AND WAVES WILL QUICKLY SUBSIDE WITH THE ARRIVAL
OF HIGH PRESSURE TONIGHT. THIS HIGH WILL SLOWLY SLIDE EAST ON
WEDNESDAY...LEADING TO INCREASING SOUTHEAST WINDS INTO WEDNESDAY
NIGHT...BUT STILL REMAINING BELOW 30 KNOTS WITH WAVES BELOW HEADLINE
CRITERIA.

&&

.CLIMATE...

RECORD LOW HIGH TEMPERATURE FOR APRIL 15:

DTW 36 (1904)
FNT 35 (1944)
MBS 33 (1944)

RECORD LOWS FOR APRIL 16:

DTW 17 (1875)
FNT 21 (1935)
MBS 21 (1935)

&&

.AVIATION...ISSUED 105 PM EDT TUE APR 15 2014

//DISCUSSION...

COLD ADVECTION AND DIURNAL HEATING WILL FACILITATE WIDESPREAD
FLURRIES AND OCCASIONAL SNOW SHOWERS FOR THE REMAINDER OF THE
DAYLIGHT HOURS ALONG WITH LOW VFR CEILING. VISIBILITY MAY BRIEFLY
DROP BELOW 3SM IN HEAVIER SHOWERS BUT WILL OTHERWISE REMAIN VFR.
GUSTY NORTHWEST WINDS WILL SUBSIDE AFTER SUNSET AS DIURNAL
STABILIZATION TAKES PLACE WHILE BUILDING HIGH PRESSURE ALLOWS FOR
CLEARING OF LOW CLOUDS. CONDITIONS WILL THEN REMAIN CLEAR BELOW
10KFT FOR THE REMAINDER OF THE NIGHT AS LIGHT SURFACE WINDS
GRADUALLY BACK TO THE SOUTHWEST.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CIGS BELOW 5000 FEET TODAY.

* HIGH CONFIDENCE IN PTYPE OF SNOW

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.

LAKE HURON...
     SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
     HURON INCLUDING OUTER SAGINAW BAY...UNTIL MIDNIGHT WEDNESDAY.

LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...JVC
LONG TERM....KURIMSKI/MM
MARINE.......KURIMSKI
CLIMATE......JVC
AVIATION.....JVC


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