Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 272250
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
650 PM EDT MON APR 27 2015

.AVIATION...

SLOW EROSION OF VFR CEILINGS IS WELL UNDERWAY AND WILL CONTINUE OVER
THE NEXT SEVERAL HOURS. ADDITIONAL ADVANCING CLOUDS OVER LAKE HURON
WILL MAKE INROADS TO THE REGION LATER THIS EVENING. CEILINGS WILL
LIKELY LOWER SOME AS THE LOWER LEVEL INVERSION STRENGTHENS THROUGH
NOCTURNAL COOLING AT THE TOP OF THE CLOUDS LAYER. STILL SOME
QUESTIONS REGARDING THE INTEGRITY OF CLOUD FIELD AS TUESDAY UNFOLDS.
EXPECTATIONS ARE FOR SOME SCATTERING...WITH BASES REMAINING IN THE
3.5-5 KFT RANGE. OTHERWISE...LIGHT NORTHERLY WINDS WILL CONTINUE.

//DTW THRESHOLD PROBABILITIES...

* MEDIUM FOR PERIODS OF CEILINGS BELOW 5000 FT THROUGH TUESDAY
  AFTERNOON.

&&

.PREV DISCUSSION...ISSUED 332 PM EDT MON APR 27 2015

SHORT TERM...THIS EVENING AND TONIGHT

SOUTHEAST MICHIGAN STILL UNDER THE INFLUENCE OF EXPANSIVE MID LEVEL
LOW PRESSURE NOW CENTERED OFF THE NEW ENGLAND COAST.  THE EFFECTIVE
MAINTENANCE OF A DEEP NORTHERLY FLOW WITHIN THE WESTERN CYCLONIC
PERIPHERY PROVIDING YET ANOTHER DAY OF COOL/CLOUDY CONDITIONS
LOCALLY.  STRONG DIURNAL COMPONENT TO THE EXISTING CLOUD
FIELD...INCREASING SUBSIDENCE AND DAYTIME MIXING BEGINNING TO LIFT
AND GRADUALLY SCATTER THIS DECK NOW ACROSS THE NORTH.  THIS PROCESS
WILL CONTINUE INTO THIS EVENING.  LATEST SOUNDING DATA AND RH FIELDS
POINT TOWARD SEEING AT LEAST PARTIAL CLEARING BY EVENING...IF NOT A
MORE AGRESSIVE CLEARING TREND...AS DIURNAL ENHANCEMENT FADES.  CLOUD
TRENDS INTO THE OVERNIGHT PERIOD LESS CERTAIN.  THERE IS THE
POTENTIAL FOR AN ADDITIONAL PERIOD OF LOW LEVEL MOISTURE ADVECTION
TO COMMENCE DURING THE EARLY MORNING HOURS AS THE FLOW VEERS
SLIGHTLY TO NORTHEASTERLY...DRAWING IN THAT HIGHER MOISTURE
RESERVOIR STILL RESIDING OVER EASTERN ONTARIO/WESTERN QUEBEC.  WILL
HOLD THE LINE WITH A PARTLY CLOUDY MENTION FOR NOW...ALLOWING
SUBSEQUENT NEAR TERM TRENDS DICTATE FURTHER ADJUSTMENT IN SKY
CONDITION. LOWS A TOUCH WARMER TONIGHT...STILL LARGELY IN THE MIDDLE
AND UPPER 30S.

LONG TERM...TUESDAY THROUGH SUNDAY

A MORE COMFORTABLE STRETCH OF SPRING WEATHER IS EXPECTED TUESDAY AND
WEDNESDAY WITH PREDOMINATELY DRY CONDITIONS AND MODERATING
TEMEPRATURES.

PERSISTENT STRATOCUMULUS SHOULD LET UP BRIEFLY AT THE START OF THE
PERIOD TUESDAY WITH TWO GOOD SURGES OF SUBSIDENCE AND A FAIRLY RAPID
LOSS IN DEEP CYCLONIC FLOW. THIS LOSS IN LOW CLOUD SHOULD ONLY BE
TEMPRORARY AS A GOOD SIGNAL EXISTS THAT LOW LEVEL RESIDUAL MOISTURE
WILL THEN BLOSSOM INTO A FAIRLY ROBUST DIURNAL CU RESPONSE. HIGHS ON
TUESDAY ARE EXPECTED TO CLIMB A COUPLE OF DEGREES ABOVE
60...ALTHOUGH AREAS HUGGING THE LAKESHORE WILL BE A FEW DEGREES
COOLER.

MUDDY MID TO UPPER LEVEL RIDGING AND LACK OF FLOW IN THE COLUMN WILL
LEAD TO PERSISTENCE FOR WEDNESDAY. THE LOW LEVELS ARE FORECASTED TO
BE MARGINALLY DRIER WHILE THERE IS SOME SIGNAL FOR SOME MIDLEVEL
MOISTURE TO POOL OVER LOWER MICHIGAN AHEAD OF THE NEXT SHORTWAVE.
STILL EXPECTING SOME MIDCLOUD...BUT BETTER LOW LEVEL LAPSE RATES
SHOULD SUPPORT HIGHS IN THE MIDDLE 60S ON WEDNESDAY.

MODEL DATA IS AGGRESIVE WITH AN UPPER LEVEL ENERGY/VORTICITY MAXIMUM
DROPPING STRAIGHT SOUTHWARD INTO THE LAKE MICHIGAN VICINITY
WEDNESDAY NIGHT AND THURSDAY. THE BOOK HASNT BEEN WRITTEN YET ON
SPECIFICS WITH MODELS TRENDING WESTERLY WITH THE QPF AXIS.
REGARDLESS...FAIRLY ROBUST SHORTWAVE AND INBOUND TRAJECTORY OF AIR
PARCELS SUPPORT AN INCREASINGLY GOOD POTENTIAL FOR A COOL DOWN AND
RAIN SHOWERS WEDNESDAY NIGHT AND THURSDAY. BUMPED POPS UPWARD FROM
THE OFFERED GRIDDED GUIDANCE. TEMPERATURES THURSDAY COULD STRUGGLE
TO CLIMB INTO THE 50S...ESPECIALLY ACROSS THE NORTHERN CWA.

RAIN CHANCES CONTINUE THROUGH THURSDAY AS A MID LEVEL DISTURBANCE
DRIFTS SOUTHWARD ACROSS THE GREAT LAKES. HIGH PRESSURE THEN QUICKLY
BUILDS INTO THE REGION BY THURSDAY NIGHT...BRINGING DRY CONDITIONS
THROUGH SATURDAY MORNING. BEYOND SATURDAY...MODELS DISAGREE ON
TIMING OF THE NEXT RAIN MAKER...WITH A COUPLE MODELS NOT EVEN
SHOWING ANY CHANCE OF RAIN FOR THE WEEKEND. FOR NOW...DUE TO THE
UNCERTAINTY...HAVE ONLY INCLUDED SLIGHT CHANCE POPS FOR THE LATE
SATURDAY NIGHT THROUGH SUNDAY TIMEFRAME. A BETTER CHANCE FOR PRECIP
ARRIVES EARLY NEXT WEEK AS A COLD FRONT TRACKS ACROSS LOWER
MICHIGAN.

MARINE...

FAVORABLE MARINE CONDITIONS TOMORROW AS SURFACE HIGH PRESSURE WILL
RESIDE ACROSS THE CENTRAL GREAT LAKES...PROVIDING LIGHT WINDS AND
LOW WAVES. WEAKENING HIGH PRESSURE WILL BE REPLACED BY WEAK SURFACE
TROUGHING LATE TOMORROW/TOMORROW NIGHT...BUT WINDS ARE STILL
EXPECTED TO REMAIN BELOW 20 KNOTS. HOWEVER...WINDS WILL BE
NORTHERLY...AND THERE COULD BE ONSHORE COMPONENT TO SUPPORT
SLIGHTLY HIGHER WAVES ALONG THE NEARSHORE WATERS.

&&

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

$$

AVIATION.....MANN
SHORT TERM...MR
LONG TERM....SF/RK
MARINE.......SF


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AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).



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