Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 260746
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
346 AM EDT SUN JUL 26 2015

.SHORT TERM...TODAY AND TONIGHT

WITH SUCH WEAK FLOW BEHIND THE FRONT...THE DRIER AIR OVER NORTHERN
LOWER HAS REALLY STRUGGLED TO MAKE IT SOUTH INTO THE AREA. THIS HAS
LEFT DEWPOINTS IN THE MID/UPPER 60S ACROSS THE AREA WHICH HAS LEAD
TO FOG DEVELOPMENT...ESPECIALLY OVER THOSE LOCATIONS IN THE THUMB
THAT RECEIVED HIGHER AMOUNTS OF RAINFALL ON SATURDAY. OBSERVATIONS
HAVE BEEN FLUCTUATING A BIT FROM 1/4SM TO 1 1/2SM SO WILL CONTINUE
WITH THE AREAS OF FOG WORDING FOR THAT AREA.

SATURDAYS TROUGH HAS FLATTENED THE LONG WAVE PATTERN ACROSS THE
NORTHERN CONUS. THE LOW AMPLITUDE RIDGE OVER THE WESTERN TWO-THIRDS
OF THE CONUS WILL START TO REAMPLIFY ONCE AGAIN THROUGH THE DAY
WHICH WILL INCREASE HEIGHTS AS FAR EAST AS LOWER MI. THIS WILL
RESULT IN SUBSIDENCE WARMING OVER AN ALREADY MILD AREA AS THE COLD
FRONTAL PASSAGE DID LITTLE TO THE THERMAL PROFILE OF THE LOCAL
AIRMASS. PERSISTENCE FORECASTING SAYS TO HEDGE ON THE HIGHER SIDE AS
INSOLATION HAS BEEN VERY EFFECTIVE OF LATE. WE WILL NOT HAVE THE SW
FLOW TODAY ADDING WAA BUT WITH TEMPS STILL NEAR 70 FOR MOST
LOCATIONS AS OF 3AM...FIND IT HARD TO GO AGAINST GUIDANCE WHICH
SUGGESTS ANOTHER DAY IN THE MID/UPPER 80S WITH FULL SUN ALL DAY. THE
DIFFERENCE TODAY WILL BE THAT THE SFC RIDGE SLIDING ACROSS MID MI
WILL BRING FLOW OFF LAKE HURON INTO THE THUMB WHICH SHOULD KEEP
COASTAL LOCATIONS CLOSER TO 80. FLOW WILL NOT BE THAT STRONG TO
REACH TOO FAR INLAND. LOWS OVERNIGHT WILL AGAIN BE DICTATED BY
DEWPOINTS WHICH WILL HOLD IN THE LOW TO MID 60S.

&&

.LONG TERM... MONDAY THROUGH SATURDAY

CONDITIONS THROUGH THE EARLY WEEK PERIOD WILL BE DEFINED BY BUILDING
UPPER HEIGHTS WORKING OVER EXISTING SURFACE HIGH PRESSURE. THIS
PATTERN WILL SUSTAIN A STRETCH OF QUIET WEATHER THROUGHOUT THE
REGION THROUGH TUESDAY...MARKED BY DEEP LAYER STABILITY UNDER
PERSISTENT SUBSIDENCE AND A WARMING MID LEVEL PROFILE.  THE RISING
THICKNESSES AND A HIGH DEGREE OF SUNSHINE WILL TRANSLATE INTO ABOVE
NORMAL WARMTH...HIGHS BOTH DAYS IN THE VICINITY OF 90 DEGREES.  THE
GRADUAL INCREASE IN LOW LEVEL MOISTURE QUALITY /DEWPOINTS MID 60S/
WILL NUDGE LATE DAY HEAT INDICES INTO THE LOWER 90S BY TUESDAY.

COLD FRONT ATTENDANT TO THE NEXT ROUND OF HEIGHT FALLS SHIFTING
ACROSS THE NORTHERN CONUS WILL ENTER THE PICTURE BY WEDNESDAY.
WINDOW WILL EXIST FOR A PERIOD OF MODEST PRE-FRONTAL MOISTURE
ADVECTION AS SOUTHWEST FLOW TEMPORARILY DEEPENS AS THE UPPER RIDGE
AXIS SHIFTS EAST.  GENERAL MODEL CONSENSUS POINTS TOWARD AN
INCREASING POTENTIAL FOR SOME DEGREE OF SHOWER/THUNDERSTORM
DEVELOPMENT WITH THIS FRONTAL PASSAGE LOCALLY.  HIGHS WEDNESDAY WILL
CARRY SOME DEPENDENCE ON THE TIMING...WITH AN EARLIER ONSET OF
PRECIPITATION AND/OR THICKER CLOUD COVER PROVIDING A GREATER
DISRUPTION TO THE DIURNAL TEMPERATURE RECOVERY.  TEMPERATURES WILL
THEN EASE BACK TOWARD NORMAL TO FINISH THE WEEK UNDER DEEPER WEST-
NORTHWEST FLOW.

&&

.MARINE...

RIDGE OF HIGH PRESSURE WILL PROVIDE A STRETCH OF FAVORABLE MARINE
CONDITIONS WITH LIGHT WINDS AND LIMITED WAVE ACTION THROUGH TUESDAY.
COLD FRONT MOVING THROUGH THE REGION WILL BRING A CHANCE FOR
THUNDERSTORMS ON WEDNESDAY.  MODEST SOUTHERLY WIND WILL DEVELOP IN
ADVANCE OF THIS FRONT DURING THE DAY.

&&

.AVIATION...ISSUED 1154 PM EDT SAT JUL 25 2015

CLEAR SKIES AND NEARLY CALM WINDS TONIGHT COULD PRODUCE RADIATION
FOG...BUT ENOUGH URBAN HEAT ISLAND EFFECT AND DRY AIR IS EXPECTED TO
FILTER IN TO MIGITATE THE FOG POTENTIAL AT TAF SITES. HIGH PRESSURE
WILL REMAIN IN CONTROL TOMORROW...MAINTAINING LIGHT WINDS WITH JUST
A TOUCH OF CU (4-8 KFT) EXPECTED TOMORROW WITH DAYTIME HEATING.

//DTW THRESHOLD PROBABILITIES...

* NONE.

&&

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

$$

SHORT TERM...DRK
LONG TERM....MR
MARINE.......MR
AVIATION.....SF


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



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