Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 241100
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
700 AM EDT THU JUL 24 2014


.AVIATION...

//DISCUSSION...

LIGHT NORTHEAST WINDS /10 KNOTS OR LESS/ WILL DEVELOP THIS MORNING
WITH THE ONSET OF DAYTIME HEATING. WINDS WILL DIMINISH DURING THE
AFTERNOON AS HIGH PRESSURE BUILDS IN FROM THE WEST AND REDUCES THE
SFC GRADIENT. SOME SCT DIURNAL CU IS EXPECTED TODAY BUT BASES WILL
BE FAIRLY HIGH GIVEN MUCH DRIER LOW LEVEL AIR.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 344 AM EDT THU JUL 24 2014

SHORT TERM...TODAY AND TONIGHT

AN ELONGATED MID LEVEL TROUGH WILL ADVANCE FROM SRN LOWER MI EARLY
THIS MORNING INTO NRN OHIO BY 15Z. MID LEVEL SUBSIDENCE IN ITS WAKE
THIS AFTERNOON WILL REINFORCE THE DRY MID LEVEL AIR ALREADY OVER THE
REGION PROVIDING A DRY DAY. LINGERING LOW LEVEL THERMAL TROUGHING
EXTENDING ACROSS THE ERN GREAT LAKES AND INTO SRN MI WILL LEAD TO
STEEPENING LOW LEVEL LAPSE RATES THIS AFTERNOON. WHILE THIS SHOULD
RESULT IN SOME DIURNAL CU DEVELOPMENT...THE DEGREE OF DRY AIR WHICH
HAS BEEN ADVECTING INTO THE LOW LEVELS OVERNIGHT SUGGEST THE
COVERAGE OF AFTERNOON CU WILL BE MUCH LESS THAN OBSERVED YESTERDAY.
SO THE STEEP LOW LEVEL LAPSE RATES AND GOOD AFTERNOON INSOLATION
WILL BOOST DAYTIME HIGHS INTO THE MID 70S. THE SPRAWLING SFC HIGH
NOW EXTENDING ACROSS THE WRN GREAT LAKES WILL BUILD ACROSS LOWER MI
THIS AFTERNOON AND EVENING. WITH SFC DEWPOINTS EXPECTED TO DROP INTO
THE 40S OVER MUCH OF SE MI THIS AFTERNOON...IDEAL RADIATIONAL
COOLING TONIGHT WILL LEAD TO RELATIVELY CHILLY MIN TEMPS FOR LATE
JULY /UPPER 40S TO LOW 50S OUTSIDE OF THE METRO DETROIT HEAT ISLAND/.

LONG TERM...

FRIDAY...UPPER LEVEL CONFLUENT FLOW WILL GIVE WAY TO GEOPOTENTIAL
HEIGHT RISES DURING THE DAY. THIS TRANSITION WILL CONTINUE TO
SUPPORT HIGH PRESSURE AND WILL ALLOW THE SURFACE RIDGE TO PERSIST
OVER THE STATE. THIS WILL BE ANOTHER DAY OF BEAUTIFUL WEATHER WITH
LOW HUMIDITY AND TEMPERATURES RISING INTO THE UPPER 70S.

FRIDAY NIGHT...MODEL SOLUTIONS HAVE SPED UP QUITE A BIT FROM THEIR
COUNTERPARTS 24 HOURS AGO BY BRINGING A SPEEDY...ZONAL UPPER LEVEL
JET CORE BACK INTO THE GREAT LAKES. NWP SOLUTIONS ARE SEEMINGLY
OVERZEALOUS WITH THE PRECIPITATION ONSET GIVEN THE AMOUNT OF DRY AIR
IN ADVANCE. NICE TO SEE THE ECMWF SLOW DOWN A LITTLE BIT AGAIN.
OTHERWISE...IT SHOULD TAKE THE MAJORITY OF THE NIGHT BEFORE MOISTURE
TRANSPORT...AND SOME MODEST LAPSE RATES MAKE IT BACK INTO
SOUTHEASTERN MICHIGAN. THE FORECAST WILL GO OUT WITH A CHANCE...BUT
IT IS FOR THE FEW HOURS LEADING INTO 12Z SATURDAY.

SATURDAY...UPPER LEVEL FORCING SEEMS TO BE COMING TOGETHER FOR A
GOOD POTENTIAL OF SHOWERS AND THUNDERSTORMS DURING THE DAY ON
SATURDAY. REALLY A GOOD JUXTAPOSITIONING OF LEFT EXIT REGION
DYNAMICS WITH WHAT COULD BE OUTSTANDING WARM ADVECTION ON THE NOSE
OF A WELL PUT TOGETHER THETA E RIDGE. MODEL SOUNDINGS ARE SHOWING
ANYWHERE FROM MODERATE TO VERY UNSTABLE CONDITIONS WITH CAPE VALUES
PUSHING UPWARDS OF 3000 J/KG. A HIGH AMOUNT OF SHEAR IS ANTICIPATED
UNDER THE DEVELOPING ZONAL FLOW OVERHEAD...0-6KM BULK SHEAR VALUES
RISING UPWARDS OF 50 KNOTS BY 00Z SUNDAY. THING TO WATCH FOR WILL BE
AMOUNT OF SUBSIDENCE/MIDLEVEL LATENT HEATING THAT WILL BE IN PLACE
FROM POSSIBLE EARLIER DAY ACTIVITY. THERE IS A GOOD CAPPING
STRUCTURE IN THE CURRENT FCST SOUNDINGS. WITH THAT STATED...THIS
APPEARS TO BE A TIMEFRAME TO WATCH FOR THE POTENTIAL OF WIDESPREAD
SEVERE WEATHER. AGGRESSIVE WORDING IN THE LATEST SWODY3.

SATURDAY NIGHT AND SUNDAY...THE SIGNAL IS THERE IN THE GLOBAL
DETERMINISTIC SOLUTIONS TO LATCH ONTO A LULL IN PRECIPITATION
CHANCES SATURDAY NIGHT AND THE FIRST PART OF SUNDAY. WENT AGGRESSIVE
WITH THAT IN THE GRIDS. DAYTIME HEATING WILL LEAD TO ANOTHER DAY OF
MODERATE INSTABILITY WITH CAPES AGAIN PUSHING OVER 2000 J/KG.
FEATURE TO WATCH WILL BE FAIRLY VIGOROUS SHORTWAVE/PV ANOMALY THAT
WILL SLINGSHOT DOWN INTO THE DEVELOPING TROUGH AND MAKE A RUN AT
SOUTHEASTERN MICHIGAN. THIS SHORTWAVE IS EXPECTED TO PASS OVERHEAD
SHORTLY AFTER 00Z MONDAY. WITH CVA AND LEFT EXIT REGION DYNAMICS
WILL WILL ALSO NEED TO WATCH THIS TIME FOR THE POTENTIAL OF ANOTHER
ROUND OF SEVERE WEATHER. IT VERY WELL COULD TURN OUT TO BE A BUSY
WEEKEND.

MARINE...

SPRAWLING SURFACE HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES FOR
THE END OF THE WEEK. FAVORABLE MARINE WEATHER IS EXPECTED THURSDAY
THROUGH FRIDAY NIGHT. THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
ENTERS THE PICTURE AGAIN ON SATURDAY AND SUNDAY. THE POTENTIAL
EXISTS FOR THESE THUNDERSTORMS TO BECOME SEVERE.

&&

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

&&

$$

AVIATION.....SC
SHORT TERM...SC
LONG TERM....CB
MARINE.......CB


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






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