Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 271936
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
336 PM EDT WED MAY 27 2015

.SHORT TERM...THROUGH TONIGHT

SURFACE TROUGH CONTINUES TO WORK ACROSS SOUTHEAST MICHIGAN THIS
AFTERNOON...WITH THE COLD FRONT FOLLOWING BEHIND...STILL STRETCHED
FROM ABOUT MT PLEASANT DOWN TOWARDS KALAMAZOO AT 300 PM. OUT AHEAD
OF THESE FEATURES...UNSTABLE AIRMASS REMAINS WITH 18Z KDTX RAOB
CONFIRMING EARLIER MODEL ESTIMATES WITH SB CAPE AROUND 1400 J/KG.
THE STRONGER STORMS HAVE BEEN ALIGNED ALONG A BOUNDARY SEEN ON KDTX
RADAR IMAGERY THAT STRETCHED FROM SOUTHERN LIVINGSTON COUNTY
NORTHEASTWARD INTO ST CLAIR COUNTY. STORMS...SOME STRONG TO
SEVERE...WILL CONTINUE THE MOST UNSTABLE AIR WILL CONTINUE TO BE
LOCATED ROUGHLY SOUTH OF A LINE FROM LEXINGTON TO HOWELL...WITH
INSTABILITY STARTING TO DECREASE AS STORMS WORK THE ATMOSPHERE OVER
AND THE COLD FRONT BEGINS TO WORK ACROSS THE AREA...BOTH HAPPENING
BY EARLY THIS EVENING. FURTHER NORTH ACROSS THE SAGINAW
VALLEY...COOLER AND DRIER AIR HAS ALREADY BEGUN TO ARRIVE WITH THE
FRONT AND ONLY EXPECTING ISOLATED LIGHT SHOWERS OVER THE NEXT FEW
HOURS.

UPPER TROUGH WILL CONTINUE TO WORK ACROSS THE WESTERN AND CENTRAL
GREAT LAKES OVERNIGHT...DRIVING THE COLD FRONT EAST. EXPECTING TO
SEE SOME DEEPER LAYER SUBSIDENCE SET IN BEHIND THE UPPER WAVE AND AS
SURFACE RIDGING BUILDS INTO THE SOUTHERN HALF OF MICHIGAN. THIS
SHOULD ALLOW SKIES TO SCATTER OUT AND WINDS TO GO LIGHT. GOOD
RADIATIONAL COOLING CONDITIONS WILL THEN PROMOTE SOME PATCH FOG
FORMATION...ESPECIALLY WHERE SOILS ARE MORE SATURATED FROM EARLIER
RAINFALL. BEST POTENTIAL FOR FOG WILL THEREFORE BE ALONG/SOUTH OF A
LINE FROM LEXINGTON TO HOWELL. MIN TEMPS WILL COOL A BIT FROM LAST
NIGHT WITH LOWER HUMIDITY AND COOLER AIR ARRIVING BEHIND THE
FRONT...WITH FORECAST MINS IN THE LOW 50S TO UPPER 50S.

&&

.LONG TERM...

SHORTWAVE RIDGE AND SMALL AREA OF SURFACE HIGH PRESSURE WILL BRING
DRY WEATHER ON THURSDAY AND THURSDAY NIGHT. WHILE TEMPERATURES WILL
STILL APPROACH 80 DEGREES IN MANY LOCATIONS...RELATIVE HUMIDITY WILL
BE LOWER AS DEW POINTS SETTLE BACK INTO THE LOW/MID 50S. DRY WEATHER
WILL PERSIST INTO PART OF FRIDAY...BUT AS SHORTWAVE RIDGE SHIFTS TO
THE EAST...MEAN UPPER LEVEL RIDGE AXIS WILL RE-ESTABLISH OVER THE
EASTERN SEABOARD AND LEAVE AREA WITHIN BROAD SOUTHWEST UPPER FLOW
WHICH WILL BRING A RETURN OF WARM AND HUMID WEATHER LATE FRIDAY INTO
SATURDAY. THIS AIRMASS WILL BE SHORTLIVED AS A VIGOROUS STORM SYSTEM
CHURNS ACROSS CANADA AND DRIVES A STRONG COLD FRONT INTO THE AREA BY
THE MIDDLE OF THE UPCOMING WEEKEND.

SHOWER AND THUNDERSTORM CHANCES WILL INCREASE NOTABLY BY FRIDAY
EVENING INTO SATURDAY AS RICHER THETA-E AIR FUNNELS BACK INTO THE
AREA AND SHORTWAVE ENERGY/TROUGHING HELPS TO FOCUS THE INCREASINGLY
UNSTABLE AIRMASS AHEAD OF THE APPROACHING COLD FRONT. MODEST MID
LEVEL WIND FIELD WILL ALSO AID IN ORGANIZED CONVECTIVE CLUSTERS WITH
A LEAST SOME POTENTIAL FOR A FEW SEVERE STORMS BY FRIDAY EVENING.
THUNDERSTORMS CHANCES THEN CONTINUE INTO SATURDAY...CULMINATING IN A
DECENT ROUND OF CONVECTION SATURDAY AFTERNOON AS THE COLD FRONT
MOVES THROUGH LOWER MICHIGAN.

A MUCH QUIETER WEATHER PATTERN THEN SETS UP LATE THIS WEEKEND INTO
THE EARLY AND MID PART OF NEXT WEEK AS A LARGE AREA OF CANADIAN HIGH
PRESSURE BUILDS INTO AND THROUGH THE GREAT LAKES AND NORTHEAST
CONUS.

IN TERMS OF TEMPERATURES...WIDESPREAD 80S CAN BE EXPECTED THURSDAY
AND ESPECIALLY FRIDAY...WITH ONLY AREAS IMMEDIATELY ALONG THE COOLER
GREAT LAKES WATERS HOLDING IN THE 70S THURSDAY. WITH THE COLD FROPA
AND SCATTERED TO NUMEROUS SHOWERS AND STORMS OVER THE AREA...HIGHS
WILL BE CAPPED IN THE 70S ON SATURDAY...WITH MUCH COOLER AIR THEN
BRING 60S FROM SUNDAY INTO MONDAY BEFORE A GRADUAL MODERATION BACK
INTO THE 70S OCCURS BY MID NEXT WEEK. AS THE AFOREMENTIONED SURFACE
HIGH SHIFTS OVER THE AREA...EXPECT PLENTY OF MINIMUM TEMPERATURES IN
THE 40S EARLY SUNDAY AND MONDAY MORNINGS.

&&

.MARINE...

A SMALL CRAFT ADVISORY WILL CONTINUE INTO THIS EVENING OVER SAGINAW
BAY THROUGH THE TIP OF THE THUMB AS SOUTHWEST FLOW IN ADVANCE OF A
WEAK COLD FRONT FUNNELS UP THE BAY AND CREATE WIND GUSTS TO AROUND
25 KNOTS. OTHERWISE...MOST MARINE AREAS WILL SEE WINDS AROUND 15
KNOTS...WITH 20 KNOT FLOW. THIS FRONT WILL ALSO FOCUS SCATTERED
SHOWERS AND THUNDERSTORMS OVER PARTS OF THE AREA THIS AFTERNOON INTO
THIS EVENING...WITH THE HIGHEST CONCENTRATION OF CONVECTION FROM
LAKE ST CLAIR SOUTH TO LAKE ERIE. DRY CONDITIONS ARE EXPECTED BY
TONIGHT INTO THURSDAY AS HIGH PRESSURE SETTLES OVER THE AREA. THESE
CONDITIONS WILL CONTINUE INTO FRIDAY BEFORE THE CHANCE OF SHOWERS
AND THUNDERSTORMS RETURN LATE IN THE DAY ON INTO FRIDAY NIGHT AND
SATURDAY.

&&

.AVIATION...ISSUED 139 PM EDT WED MAY 27 2015

SHOWERS AND THUNDERSTORMS HAVE FILLED IN OVER SOUTHEAST
MICHIGAN...AT LEAST FROM FNT SOUTH...AHEAD OF A SURFACE TROUGH AND
COLD FRONT. ACTIVITY IS EXPECTED TO CONTINUE INTO THE EARLY EVENING
BEFORE THE COLD FRONT WORKS ACROSS THE AREA AND PUSHES STORMS EAST.
SEVERE WEATHER IS POSSIBLE WITH THESE STORMS FROM PTK SOUTH. THE
MOST LIKELY THREAT IS DAMAGING WIND GUSTS TO 50 KNOTS...HOWEVER HAIL
TO 1 INCH IS ALSO POSSIBLE. OTHERWISE...SOUTHWEST WINDS WILL GUST TO
AROUND 25 KNOTS INTO THE EARLY EVENING BEFORE TURNING WEST AND
DECREASING BEHIND THE FRONT. SURFACE HIGH PRESSURE BUILDING INTO
SOUTHERN LOWER MICHIGAN LATE TONIGHT WILL ALLOW WINDS TO BECOME VERY
LIGHT. THIS MAY PROMOTE LIGHT FOG DEVELOPMENT AFTER 08Z.

FOR DTW...ADDITIONAL SHOWERS AND THUNDERSTORMS MAY IMPACT THE
TERMINAL BEFORE 22Z. SOME OF THESE STORMS MAY BE STRONG TO SEVERE.
WINDS WILL CONTINUE TO GUST TO AROUND 25 KNOTS THROUGH EARLY EVENING
BEFORE TURNING WEST AND DECREASING.

//DTW THRESHOLD PROBABILITIES...

* HIGH PROBABILITY FOR CEILINGS AT OR BELOW 5000 FT THIS AFTERNOON
  INTO EARLY EVENING.

* MEDIUM POTENTIAL FOR ADDITIONAL THUNDERSTORMS TO AFFECT THE
  TERMINAL FROM 18Z TO 22Z.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LHZ421-422-
     441.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...HLO
LONG TERM....DG
MARINE.......DG
AVIATION.....HLO


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