Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 300352
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1152 PM EDT MON JUN 29 2015


.AVIATION...

THE LOW LEVEL S-SE WINDS HAVE BEEN ADVECTING A STRATUS DECK
NORTHWARD THIS EVENING. SATELLITE TRENDS SUGGEST THESE CLOUDS WILL
EVENTUALLY LIFT NORTH INTO FNT AND MBS BY OR SHORTLY AFTER 06Z.
CLOUD BASES ARE EXPECTED TO TREND TOWARD MVFR OVER THE NEXT FEW
HOURS AS ADDITIONAL LOW LEVEL MOISTURE ARRIVES FROM THE SOUTHEAST.
THESE LOW CLOUDS WILL LIKELY PERSIST THROUGH DAYBREAK UNDER A
SHALLOW INVERSION BEFORE DAYTIME HEATING LIFTS THE CLOUDS TO A VFR
STRATO CU FIELD BY AFTERNOON.

FOR DTW...THERE HAVE BEEN A FEW OBSERVATIONS ACROSS NRN OHIO WITH
IFR CIGS IN THE VICINITY OF A WEAK SURFACE LOW. THIS FEATURE WILL
LIFT EAST OF METRO DETROIT 08-12Z AND WILL SUPPLY SOME ADDITIONAL
LOW LEVEL MOISTURE ADVECTION. THIS WILL REMAIN SUPPORTIVE OF A
PERIOD OF IFR CEILINGS AT METRO EARLY TUES MORNING.

//DTW THRESHOLD PROBABILITIES...

* HIGH IN CIGS BELOW 5000 FT TONIGHT AND TUES MORNING.

* MEDIUM IN THUNDERSTORMS TUESDAY AFTERNOON AND EVENING.

&&

.PREV DISCUSSION...ISSUED 654 PM EDT MON JUN 29 2015

UPDATE...

EARLIER SHOWERS AND ISOLATED THUNDERSTORMS HAVE LIFTED NORTH OF
THE REGION...WITH LITTLE INSTABILITY REMAINING OVER SE MI. A MID
LEVEL SHORT WAVE NOW ROTATING ALONG THE MI/IN BORDER WILL PROVIDE
A CHANCE FOR SOME LIGHT SHOWERS/SPRINKLES ACROSS METRO DETROIT
AND POINTS SOUTH TONIGHT...BUT THAT IS ABOUT IT. IN LIGHT OF
CURRENT OBSERVATIONS...THE FORECAST WILL BE UPDATED TO REDUCE
CLOUD COVER THIS EVENING AND LOWER POPS SUBSTANTIALLY TONIGHT.

PREV DISCUSSION...ISSUED 322 PM EDT MON JUN 29 2015

SHORT TERM...TONIGHT

SUNNY START TO THE DAY ALLOWED TEMPERATURES TO PUSH TO AROUND 80
DEGREES OVER TRI-CITIES REGION...FLINT VICINITY...AND NORTHERN THUMB
REGION THIS AFTERNOON...COUPLED WITH MODEST MOISTURE ADVECTION
ALLOWING SOME (SCT) SHOWERS AND ISOLATED THUNDERSTORMS TO GO UP WITH
MUCAPES AROUND 500 J/KG.

POSITIVELY TILTED UPPER LEVEL LONGWAVE TROUGH IN PLACE OVER THE
WESTERN/GREAT LAKES...WITH SEASONABLY COLD MID LEVELS...AS 12Z DTX
SOUNDING INDICATED A 500 MB TEMP OF -15 C. ONE SHORTWAVE WHICH
PRODUCED HEAVIER SHORTWAVE ACTIVITY OVER NORTHWEST OHIO EARLY TODAY
HAS PASSED JUST TO OUR SOUTHEAST...TAKING WITH IT THE MAJORITY OF
THE DEEPER MOISTURE. HOWEVER...A SECOND PV MAXIMUM/SHORTWAVE NEAR
CHICAGO WILL SKIM ACROSS THE SOUTHERN MICHIGAN BORDER...AND 850-700
MB CIRCULATION IS FORECASTED TO SLOWLY LIFT THROUGH SOUTHEAST
MICHIGAN THIS EVENING. THIS FEATURE WILL HAVE LITTLE INSTABILITY TO
WORK WITH...BUT SHOULD ALLOW LOW CLOUDS AND MOISTURE TO SPREAD UP
FROM THE SOUTH WITH A CHANCE OF SOME DRIZZLE OR LIGHT RAIN SHOWERS
WITH THE WEAK CIRCULATION. SURFACE DEW PTS HOLDING IN THE UPPER 50S
TO AROUND 60 DEGREES WILL PROVIDE THE BOTTOM FOR MINS.

LONG TERM...TUESDAY THROUGH SUNDAY

LONGWAVE TROUGH WILL HOLD OVER THE REGION THROUGH THE WEEK BUT WITH
MANY SMALL SCALE FEATURES TO TRY TO ACCOUNT FOR. MODELS HAVE BEEN
STRUGGLING WITH THIS PATTERN AND THESE SMALLER WAVES THROUGHOUT THE
PAST WEEKEND AND EXPECT THIS TO CONTINUE MOVING FORWARD THROUGH MID
WEEK. FOR THIS REASON IT WILL BE HARD TO GO WITH POPS HIGHER THAN
CHANCE FOR ANY PERIOD UNTIL THE SHORTWAVES AND SFC FEATURES START TO
SHOW THEMSELVES AND THEIR LOCATIONS.

THE UPPER LEVEL TROUGH AXIS WILL REACH CENTRAL MI TUESDAY MORNING.
THE TRACK OF AN EXITING SFC LOW OVER LAKE ERIE MAY KEEP THE
WEAKENING DEFORMATION BAND AND PRECIP SHIELD OVER THE EASTERN
COUNTIES. A SHORTWAVE RIDGE WILL BE SLIDING ACROSS NORTHERN LOWER
WHICH MAY PUT AN EARLIER END TO THE LINGERING SHOWERS THOUGH. CHANCE
OF SHOWERS/TSTORMS WILL RETURN EARLY TUESDAY AFTERNOON AS THE NEXT
WAVE TRACKS THROUGH LOWER MI ALONG A FRONTAL BOUNDARY ON THE
BACKSIDE OF THE LONGWAVE TROUGH. THE WAVE AND ASSOCIATE SFC
REFLECTION ARE FORECAST TO TRACK RIGHT THROUGH LOWER MI DURING PEAK
HEATING BETWEEN 18-00Z WHICH SHOULD AIDE IN CONVECTION. MODELS SHOW
CAPE PEAKING UNDER 500 J/KG WITH LESS THAN 20 KNOTS THROUGHOUT THE
COLUMN. SO COULD SEE SOME SCATTERED SHOWERS/TSTORMS POP
UP...ESPECIALLY CLOSE TO THE FRONT IN THE LATE AFTERNOON. THOUGH
OVERALL FORCING IS NOT OVERWHELMING...PWATS ON WILL REMAIN NEAR 1.5
INCHES AND WHEN COMBINED WITH SLOW STORM MOTION COULD LEAD TO SOME
HEAVY RAINFALL. WITH THE LONGWAVE TROUGH AXIS PIVOTING THROUGH THE
AREA OVERNIGHT...EXPECT SOME SHOWERS TO LINGER OVERNIGHT AS THE LOW
SLOWLY LIFTS NE OUT OF THE AREA.

ADDITIONALLY...A SECONDARY TRAILING COLD FRONT/TROUGH WILL DRIFT
SOUTHWARD INTO MID MI WHICH MAY NEED TO BE WATCHED FOR POTENTIAL
SHOWER ACTIVITY. MORE LIKELY THE TROUGH WILL NOT IGNITE SHOWERS
UNTIL NEXT ROUND OF DIURNAL INSTABILITY BUILDING ON WEDNESDAY. HIGH
PRESSURE WILL BE BUILDING IN FROM THE NW BEHIND THE EXITING TROUGH
SO PRECIP SHOULD WANE WEDNESDAY INTO THE OVERNIGHT ACCORDINGLY.

BAGGY LONGWAVE UPPER TROUGH IN PLACE THURSDAY INTO THE WEEKEND.
ASIDE FROM THURSDAY WHICH HAS HAD THE BEST SIGNAL FOR
SUBSIDENCE...CANNOT RULE OUT PRECIP THROUGH THE WEEKEND...BUT UNTIL
A MORE COHERENT FORCING SIGNAL IS DEPICTED WITH ANY SORT OF
CONTINUITY WILL KEEP THE FORECAST DRY. WARMING TREND FOR THE WEEKEND
INTO EARLY NEXT WEEK AS MODELS HINTING AT UPPER FLOW REORGANIZING
INTO MORE OF A ZONAL CONFIGURATION.

MARINE...

FAIRLY LIGHT WINDS WILL PERSIST ACROSS THE CENTRAL GREAT LAKES FOR
THE BETTER PART OF THE UPCOMING WEAK. A LOW PRESSURE SYSTEM TRACKING
THROUGH UP THROUGH LAKE ERIE THIS EVENING WILL PRODUCE LOCALLY
HIGHER WINDS OVER WESTERN LAKE ERIE INTO THE OVERNIGHT. A SMALL
CRAFT ADVISORY CONTINUES FOR THE MICHIGAN WATERS OF LAKE ERIE FOR
INCREASED WIND GUSTS. WINDS WILL WEAKEN LATE TONIGHT AS THE LOW
LIFTS INTO ONTARIO. AN UPPER LEVEL DISTURBANCE WILL THEN DROP INTO
REGION ON TUESDAY WHICH WILL RESULT IN LOW PRESSURE RETURNING OVER
THE CENTRAL GREAT LAKES.

&&

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

$$

AVIATION.....SC
UPDATE.......SC
SHORT TERM...SF
LONG TERM....DRK/DT
MARINE.......DRK


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



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