Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 140747
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
347 AM EDT MON JUL 14 2014

.SHORT TERM...TODAY AND TONIGHT

AN AREA OF SHOWERS...ASSOCIATED WITH A POCKET OF HIGH LOW LEVEL
THETA-E VALUES...WILL MOVE THROUGH THE EXTREME SOUTHERN CWA DURING
THE EARLY MORNING HOURS. ONCE THESE SHOWERS MOVE THROUGH THERE WILL
BE A QUIET PERIOD THIS MORNING AS LOWER THETA-E AIR ADVECTS IN AHEAD
OF A POWERFUL LOW PRESSURE SYSTEM SEEN DIVING SOUTH OVER THE UPPER
MISSISSIPPI VALLEY ON WATER VAPOR IMAGERY. THIS POSITIVELY TILTED
TROUGH WILL DIVE SOUTHEAST OVER THE WESTERN GREAT LAKES
TODAY...BECOMING NEGATIVELY TILTED LATE TONIGHT AS IT LIFTS THROUGH
THE CENTRAL GREAT LAKES.

THE QUIET TIME AHEAD OF THIS LOW WILL ALLOW SOUTHEAST MICHIGAN TO
WARM INTO THE UPPER 70S TO LOWER 80S. THIS WILL ALLOW MUCAPES TO
BUILD TO 0.5 TO 1.0 J/G ACROSS THE SOUTHERN CWA LATE THIS AFTERNOON
INTO THE EVENING HOURS WHEN THE LARGE LOW TRACKS THROUGH THE CENTRAL
GREAT LAKES. THIS COULD PRODUCE SOME STRONG STORMS GIVEN THE
DYNAMICS AND INSTABILITY. HOWEVER IT APPEARS THE BEST CHANCE
FOR SEVERE WEATHER WILL BE FURTHER SOUTH IN THE WARM SECTOR WITH THE
DEEPER MOISTURE AND BETTER INSTABILITY. THAT BEING SAID...A FEW
STORMS COULD APPROACH SEVERE LIMITS ACROSS THE FAR SOUTH NEAR THE
OHIO BORDER.

AS THE LOW LIFTS OUT LATER TONIGHT THE DRY SLOT WILL BE PULLED IN
FROM THE SOUTHWEST...BRINGING LOWER PRECIPITATION CHANCES AFTER
MIDNIGHT AS THIS SLUG OF DRY AIR PUSHES INTO THE AREA. THE COOL AIR
BEHIND THE LOW WILL BRING NIGHTTIME LOWS DOWN INTO THE 50S ACROSS
THE AREA.

&&

.LONG TERM...

THE STORY IN THE EXTENDED CONTINUES TO BE THE WELL
ADVERTISED...UNSEASONABLY STRONG/COLD...UPPER LEVEL TROUGH THAT WILL
TAKE OVER THE EASTERN CONUS THROUGH MID WEEK. THE UPPER LOW WILL
SPLIT INTO A PAIR OF CLOSED LOWS EACH AROUND 550DAM ON MONDAY. THE
TRAILING LOW WILL DROP INTO THE TROUGH RIGHT OVER LOWER MI
TUESDAY...FILLING IN SLIGHTLY TO AROUND 554DAM...BEFORE THEN EXITING
INTO ONTARIO WEDNESDAY. TEMPERATURES THROUGHOUT THE COLUMN WILL BE
IMPRESSIVE FOR JULY/S STANDARDS COMING IN AROUND -23C AND 5C AT
500MB AND 850MB RESPECTIVELY AS THE COLD CORE PASSES OVER NORTHERN
LOWER MI TUESDAY. THE ENHANCED LAPSE RATES DUE TO THE CAA AND
WIDESPREAD LIFT DUE TO THE UPPER LOW WILL RESULT IN PLENTY OF CLOUD
COVER IN THE LOW/MID LEVELS. MODEL SOUNDINGS SHOW THE MOISTURE
TRAPPED BELOW 10KFT. MODELS ARE ALSO COMING TOGETHER IN DEVELOPING A
SFC LOW OVER SOUTHERN ONTARIO UNDER THE UPPER LOW. THE RESULTANT
DEFORMATION REGION WILL PASS OVER SE MI WHICH ALSO ENCOURAGES
PRECIPITATION. THIS WILL ALL YIELD HIGH TEMPS ONLY IN THE
MID/UPPER 60S TUESDAY WITH SCATTERED RAIN SHOWERS TUESDAY AND
TUESDAY NIGHT.

HEIGHTS WILL BE ON THE RISE THROUGH THE DAY WEDNESDAY MAINLY
BECAUSE THE CORE OF THE UPPER LOW IS DRIFTING NE. SE MI WILL STILL
RESIDE UNDER THE INFLUENCE OF THE DEEP TROUGH WITH UPPER LEVEL TEMPS
INCREASING SLIGHTLY TO -15/8C AT 500/850MB. CLOUDS WILL AGAIN BE
RATHER THICK AS A TROUGH/FRONT ROTATES AROUND THE UPPER LOW THROUGH
MI. WITH STILL FAVORABLE LAPSE RATES AND LL MOISTURE TO WORK
WITH...THIS TROUGH COULD BRING ANOTHER ROUND OF SHOWERS TO THE AREA.
TEMPERATURES WILL RESPOND TO OVERALL HEIGHT RISES BY A FEW DEGREES
WITH MOST LOCATIONS TRYING TO MAKE A RUN AT 70. THIS IS ABOUT 15
DEGREES BELOW NORMAL FOR MID JULY.

QUIETER WEATHER WILL MAKE ITS RETURN ON THURSDAY AS MID LEVEL RIDGE
STARTS PUSHING ACROSS THE CENTRAL PLAINS WHILE SFC RIDGE SLIDES IN
BEHIND THE DEPARTING TROUGH. THIS WILL LEAD TO A WARMING TREND INTO
THE WEEKEND WITH MOSTLY DRY CONDITIONS. A FEATURE OF NOTE WILL BE A
SOUTHERN STREAM WAVE WHICH IS FORECAST TO TRACK THROUGH THE
TENNESSEE VALLEY AND UP INTO OHIO SATURDAY. MODELS HAVE BEEN
FLIRTING WITH A TRACK THAT WOULD BRUSH THE EASTERN COUNTIES OF SE
MI. VERY LOW CONFIDENCE AT THIS POINT BUT SINCE THEY ARE TRENDING
MORE NW WITH IT ADDED IN A SLIGHT CHANCE DURING THE DAY.

&&

.MARINE...

A FEW THUNDERSTORMS WILL BE POSSIBLE TODAY AS A FRONT DRAPED ACROSS
SOUTHERN MICHIGAN DRIFTS SLOWLY SOUTHWARD. COVERAGE WILL BE MINIMAL
AND WILL MAINLY AFFECT SOUTHERN LAKE HURON...LAKE ST CLAIR AND LAKE
ERIE. LIGHT WINDS ON MONDAY WILL GIVE WAY TO WESTERLY WINDS GUSTING
TO AROUND 20 KNOTS ON TUESDAY AS MUCH COOLER AIRMASS MOVES INTO THE
REGION. THESE GUSTS ARE EXPECTED TO STAY BELOW SMALL CRAFT ADVISORY
CONDITIONS AT THIS TIME. THOUGH WE MAY NOT ACHIEVE SMALL CRAFT
CRITERIA...THERE WILL BE A THREAT OF WATERSPOUTS TUESDAY AND
WEDNESDAY AS THE COOLER AIR FLOWS OVER RELATIVELY WARMER LAKE WATER.
A CHANCE OF WATERSPOUTS HAS BEEN ADDED TO THE FORECAST FOR THE
FAVORABLE MARINE ZONES INCLUDING SOUTHERN LAKE HURON...LAKE ST CLAIR
AND LAKE ERIE.

&&

.AVIATION...ISSUED 1153 PM EDT SUN JUL 13 2014

//DISCUSSION...

A SLOW MOVING FRONTAL BOUNDARY WILL EXTEND ACROSS SE MI MON MORNING
INTO LATE AFTERNOON. THIS FRONT WILL SUSTAIN SOME WIDELY SCATTERED
SHOWERS DURING THE EARLY MORNING HOURS. ENOUGH LOW LEVEL DRY AIR IS
PRESENT TO WHERE BASES WILL REMAIN VFR. DAYTIME HEATING WILL MAKE
SHOWERS AND A FEW THUNDERSTORMS POSSIBLY BY LATE MONDAY
AFTERNOON...PARTICULARLY SOUTH OF PTK WHERE INSTABILITY IS EXPECTED
TO BE HIGHER.

//DTW THRESHOLD THREATS...

* LOW CONFIDENCE IN THUNDERSTORM POTENTIAL LATE MONDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...KURIMSKI
LONG TERM....DRK
MARINE.......DRK
AVIATION.....SC


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





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