Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 111642
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1242 PM EDT FRI JUL 11 2014


.AVIATION...

//DISCUSSION...

DIURNAL VFR CU HAS FLARED UP FROM PTK SOUTHWARD. COVERAGE IS
EXPECTED TO REMAIN SCT AT MOST...AND DIMINISH SOMEWHAT BY
MIDAFTERNOON. IMPACTS WILL REMAIN NIL OVERNIGHT WITH ONLY PERIODS
OF MID/HIGH CLOUDS OVER THE TERMINALS. MOISTURE WILL INCREASE
DURING THE DAY TOMORROW AS DEEPER SSW FLOW
DEVELOPS...HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN
PREDOMINANTLY VFR THROUGHOUT THE FORECAST PERIOD.

FOR DTW...THERE REMAINS A LIMITED WINDOW BEFORE 21Z TODAY FOR BRIEF
CEILINGS NEAR THE 5KFT THRESHOLD...BUT COVERAGE SHOULD REMAIN
MOSTLY FEW-SCT. A FEW SHOWERS AND PERHAPS A THUNDERSTORM CANNOT BE
RULED OUT AFTER AROUND 21Z TOMORROW...BUT COVERAGE SHOULD BE TOO
LIMITED TO INCLUDE IN THE TAFS AT THIS TIME.

//DTW THRESHOLD THREATS...

* LOW CONFIDENCE ON CEILINGS AOB 5000 FT EARLY THIS AFTERNOON AND
  LATE TOMORROW AFTERNOON.

* LOW CONFIDENCE ON A STRAY THUNDERSTORM IMPACTING THE TERMINAL
  AFTER 21Z TOMORROW.

&&

.PREV DISCUSSION...ISSUED 349 AM EDT FRI JUL 11 2014

SHORT TERM...TODAY AND TONIGHT

A QUIET DAY ON TAP FOR SE MI AS RIDGING HOLDS OVER THE AREA ONE MORE
DAY. MODELS INDICATE CONTINUED WARMING IN THE 800-500MB LAYER FROM
THURSDAY...STRENGTHENING THE SUBSIDENCE INVERSION THROUGH THE
AFTERNOON. AMOUNT OF MOISTURE IN THE COLUMN IS ALSO PROGGED TO
DECREASE SOME FROM 0.8 INCHES TO 0.6 INCHES BY THIS AFTERNOON.
SHOULD BE ENOUGH TRAPPED UNDER THE INVERSION TO SPARK A FEW
AFTERNOON CU. LOOK FOR TEMPS TO JUMP A COUPLE DEGREES FROM YESTERDAY
TO THE UPPER 70S/NEAR 80.

CHANGES START TO COME OVERNIGHT AS STRONG UPPER LEVEL JET STARTS TO
WORK THROUGH THE NORTHERN GREAT LAKES. THIS WILL OCCUR AS UPPER
LEVEL PATTERN BECOMES ZONAL ACROSS THE NORTHERN TIER OF THE CONUS
BETWEEN THE DOMINATE UPPER LOW OVER CENTRAL CANADA AND HIGH OVER
MOST OF THE SOUTH/CENTRAL CONUS. UPPER LEVEL CLOUD DEBRIS WILL BEGIN
WORKING INTO LOWER MI AS A RESULT OF THE SHORTWAVE LOCATED AT THE
NOSE OF THE JET AND THE APPROACHING COLD FRONT ENTERING WESTERN WI.
SOUTHWESTERLY FLOW WILL INCREASE SOME AS THE RIDGE GETS SHUNTED
EAST. THIS WILL ALLOW THE THETA E GRADIENT TO WORK ACROSS LOWER MI
AS WELL. THE INCREASING CLOUDS/MOISTURE...SW FLOW...AND THETA E
GRADIENT WILL KEEP TEMPERATURES UP IN THE LOW 60S OVERNIGHT.

LONG TERM...SATURDAY THROUGH THURSDAY

A SURFACE HIGH WILL PUSH EAST TOWARDS THE WESTERN ATLANTIC ON
SATURDAY...ALLOWING A MID LEVEL SHORTWAVE TO TRACK THROUGH THE
CENTRAL GREAT LAKES. WITH NVA AND ABUNDANT DRY AIR IN PLACE SATURDAY
MORNING...RAIN IS NOT EXPECTED FOR THE FIRST PART OF THE DAY. LATER
IN THE AFTERNOON HIGHER THETA-E VALUES ADVECT IN FROM THE WEST AS A
WEAK SHORTWAVE TRACKS THROUGH THE AREA WHILE SOUNDINGS SHOW A
MOISTENING PROFILE. IN ADDITION THE LOW LEVEL JET REALLY BEGINS INCREASING
DURING THE EVENING HOURS...WITH LIKELY POPS EXPECTED SATURDAY
NIGHT AS YET ANOTHER SHORTWAVE TRACKS THROUGH THE CENTRAL GREAT
LAKES REGION AND VIGOROUS DIVERGENCE AS A STRONG 100 KNOT UPPER
LEVEL JET COUPLED JET STRUCTURE MOVES THROUGH THE GREAT LAKES
REGION. TEMPERATURES ON SATURDAY SHOULD BE ABLE TO GET INTO THE
80S AS PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL SATURDAY
AFTERNOON. LOWS SATURDAY NIGHT WILL BE RELATIVELY WARM IN THE
MIDDLE TO UPPER 60S GIVEN THE ABUNDANT CLOUD COVER AND THE REGION
IN THE WARM SECTOR.

A COLD FRONT WILL PUSH THROUGH THE CENTRAL GREAT LAKES ON
SUNDAY...HOWEVER HIGHS ARE STILL EXPECTED TO GET TO AROUND 80 AS THE
PUSH OF COLD AIR IS NOT EXPECTED UNTIL SUNDAY NIGHT WHEN LOWS ARE
EXPECTED TO DIP INTO THE LOW TO MID 60S. ALTHOUGH SURFACE RIDGING
WILL BUILD IN FROM THE WEST...ANOTHER SHORTWAVE WILL DIVE SOUTH
ALONG WITH A RIBBON OF HIGHER THETA-E AIR SUNDAY NIGHT...CONTINUING
THE CHANCE FOR MORE RAIN DURING THE OVERNIGHT HOURS.

THE BIG STORY FOR THE EXTENDED IS THE COLD LOW PLUNGING SOUTH MONDAY
AND TUESDAY...SENDING 850 MB TEMPERATURES PLUNGING INTO THE SINGLE
DIGITS BY TUESDAY. THIS BLAST OF COOL AIR WILL SEND DAYTIME HIGHS
DOWN TO AROUND 70 ON TUESDAY...WITH LOWS IN THE LOW TO MID 50S ON
TUESDAY NIGHT. WEDNESDAY WILL NOT BE MUCH WARMER WITH HIGHS STILL
AROUND 70 DEGREES. THIS STRETCH OF COOL WEATHER COULD GET CLOSE TO
SOME RECORD COOL TEMPERATURES WITH RECORD LOWS AND RECORD LOW
MAXIMUMS AT RISK OF BEING BROKEN...ESPECIALLY ON WEDNESDAY WHEN
THESE VALUES ARE RELATIVELY HIGH COMPARED TO THE REST OF THE DATA
SET. ALTHOUGH WE REMAIN IN A TROUGH ON THURSDAY...850 MB
TEMPERATURES REBOUND TO AROUND 10 DEGREES...WITH HIGHS BACK IN THE
MIDDLE 70S ACROSS MUCH OF THE AREA.

MARINE...

HIGH PRESSURE WILL PROVIDE LIGHT WINDS AND LOW WAVES TODAY. LIGHT
SOUTHERLY WINDS TONIGHT WILL BRING WARMER AND MORE HUMID AIR INTO
THE REGION WITH A CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE
WEEKEND...OTHERWISE WINDS LOOK TO BE STAYING LIGHT.

&&

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

&&

$$

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


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