Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 232308
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
708 PM EDT WED APR 23 2014


.AVIATION...

//DISCUSSION...

HIGH PRESSURE SETTLING INTO THE REGION WILL BRING VFR CONDITIONS
THROUGH 00Z FRIDAY. NORTHERLY WINDS WILL BECOME LIGHT AND VARIABLE
THIS EVENING AS THE ATMOSPHERE DECOUPLES. HIGH/MID CLOUDS
WILL INCREASE AND THICKEN OVERNIGHT AND THURSDAY AHEAD OF AN
APPROACHING LOW PRESSURE SYSTEM. RAIN FROM THIS SYSTEM IS EXPECTED
TO HOLD OFF UNTIL AFTER 00Z FRI.

//DTW THRESHOLD THREATS...

* NONE

&&

.PREV DISCUSSION...ISSUED 328 PM EDT WED APR 23 2014

SHORT TERM...TONIGHT

SURFACE HIGH PRESSURE CENTERED OVER THE WESTERN GREAT LAKES WILL
SLIDE OVERHEAD TONIGHT...KEEPING DRY AND QUIET WEATHER OVER
SOUTHEAST MICHIGAN. HIGH CLOUDS WILL INCREASE OVERNIGHT AS THE NEXT
LOW PRESSURE SYSTEM APPROACHES...WITH SOME MID-LEVEL CLOUDS WORKING
IN TOWARDS DAYBREAK. CROSS-SECTIONS OF MODEL MOISTURE...WHICH LOOKS
TO BE POSITIONED HIGH BUT EXTEND QUITE DEEP...AND SATELLITE IMAGERY
SUPPORT A MOSTLY CLOUDY WORDING BY LATE TONIGHT. AN ELEVATED WARM
FRONT AHEAD OF THE LOW ORGANIZING OVER THE PLAINS IS FORECAST TO
START WORKING UP ACROSS LOWER MICHIGAN LATE. WILL MAINTAIN A DRY
FORECAST WITH THIS AS THE THE LOW-LEVEL JET AND A VERY MODEST SURGE
OF THETA-E ADVECTION REMAIN WELL TO OUR WEST. LITTLE CHANGE WAS
NECESSARY TO MIN TEMPS AS GOOD RADIATIONAL COOLING CONDITIONS SET UP
EARLY IN THE NIGHT BEFORE HIGH CLOUDS MOVE IN. MIN TEMPS SHOULD
RANGE FROM THE UPPER 20S TO MID 30S...WARMEST IN THE DETROIT HEAT
ISLAND AND WESTERN SECTIONS OF THE FORECAST AREA WHERE CLOUDS WILL
ARRIVE AND THICKEN A LITTLE EARLIER.

LONG TERM...

MID AND HIGH CLOUDS WILL STREAM ACROSS THE RIDGE AXIS THROUGH THE
DAY ON THURSDAY BRINGING A MOSTLY CLOUDY SKY CONDITION, PARTICULARLY
THROUGH THE FIRST HALF OF THE DAY. AT THE SAME TIME, EASTWARD
PROGRESSION OF THE LARGE SCALE PATTERN WILL FAVOR REBOUNDING
HEIGHTS/TEMPS THROUGHOUT THE COLUMN WHICH, COMBINED WITH PROGGED
BOUNDARY LAYER GROWTH TO 850MB, SHOULD ALLOW HIGHS TO REBOUND
SEVERAL DEGREES OVER TODAY`S HIGHS. SE WINDS WILL, HOWEVER, MAINTAIN
A CHILL IN THE AIR IN LAKE SHADOWED REGIONS AND WILL TEMPER
EXPECTATIONS TO UPPER 50S OVERALL.

RIDGE AXIS WILL TRANSIT SE MICHIGAN LATE THURSDAY, USHERING IN A
PERIOD OF INCREASING MID-LEVEL ISENTROPIC ASCENT. THIS WILL SERVE TO
MOISTEN THE COLUMN, BUT MODEL SOLUTIONS SUGGEST NOTHING IN THE WAY
OF PRECIP WITH THIS INCREASING MOISTURE TRANSPORT/ASCENT. THE
SOLUTIONS ARE BELIEVABLE GIVEN THE DEEP LAYER OF REMNANT DRY AIR IN
THE LOWEST 12KFT, SO A DRY FORECAST LOOKS TO BE IN ORDER UNTIL THE
APPROACH OF THE PRIMARY TROUGH AXIS LATE.

OVERALL MODEL DEPICTION OF THURSDAY NIGHT`S SYSTEM CONTINUES TO
FAVOR SLOWER SOLUTIONS AS IMPROVING DATA QUALITY ALLOWS FOR BETTER
RESOLUTION OF INTERACTING NORTHERN/SOUTHERN WAVES. THE STRONGEST
SHORTWAVE FORCING WILL OCCUR WITH THE TWO INDIVIDUAL WAVES, WHICH
WILL REMAIN UNPHASED, AND WILL THUS SPLIT THE REGION LEAVING SE
MICHIGAN IN A ZONE OF RELATIVELY WEAK/LESS ORGANIZED LARGE SCALE
ASCENT. APPROACH OF THE MID-LEVEL TROUGH AXIS WILL HELP TO ORGANIZE
DEEP LAYER ISENTROPIC ASCENT, BUT NOT UNTIL CLOSER TO 09Z OR SO. LOW
STATIC STABILITY AND STRONGER FORCING BY THIS TIME SHOULD ALLOW
SHOWERS TO BEGIN PUSHING INTO THE AREA BY THIS TIME. THE BULK OF THE
RAINFALL WILL THEN TRANSIT THE AREA ALONG/AHEAD OF THE ELONGATED
500MB FRONTAL ZONE WHERE SYSTEM RELATIVE FGEN WILL REMAIN FAIRLY
ACTIVE. RAPID DEAMPLIFICATION OF THE FLOW IN THE WAKE OF THE TROUGH
WILL FAVOR A QUICK EXIT TO PRECIP AS DRY AIR AGGRESSIVELY SPREADS
OVER THE REGION MID/LATE MORNING FRIDAY, SO NOT EXPECTING MUCH MORE
THAN A 3-4 HOUR PERIOD OF SHOWERS FOR MOST AREAS. THIS WILL ALSO
ALLOW MIXING HEIGHTS TO RAPIDLY DEEPEN DURING THE AFTERNOON HOURS
RESULTING IN GUSTY WINDS AND TEMPERATURES QUICKLY REBOUNDING FROM
THE 40S INTO LOW TO MID 60S. SECONDARY ROUND OF NORTHERN STREAM
HEIGHT FALLS WILL USHER A COLD FRONT THROUGH THE AREA FRIDAY NIGHT.
EVENTUAL DEVELOPMENT OF A CLOSED LOW OVER THE EASTERN UNITED STATES
WILL ENSURE THE CHILLY AIR STAYS IN PLACE FOR THE REMAINDER OF THE
EXTENDED.

MARINE...

LIGHT TO OCCASIONALLY MODERATE SOUTHEAST FLOW WILL DEVELOP LATE
TONIGHT AND PERSIST THROUGH INTO EARLY FRIDAY NIGHT AS A WEAK
PRESSURE GRADIENT MAINTAINS RELATIVELY TRANQUIL CONDITIONS ACROSS
THE WATERS. WINDS WILL QUICKLY SHIFT TO THE WEST ON FRIDAY BEHIND A
WEAK FRONT AND WILL THEN QUICKLY RAMP UP LATE FRIDAY NIGHT AS A
STRONGER COLD FRONT MOVES THROUGH THE GREAT LAKES. AS A
RESULT...MODERATE NORTHWEST WINDS MAY BE ACCOMPANIED BY GUSTS TO
NEAR-GALES THROUGH EARLY SATURDAY.

&&

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

&&

$$

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


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