Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 030525
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
125 AM EDT MON AUG 3 2015


.AVIATION...

LINE OF THUNDERSTORMS HAS SETTLED INTO PORTIONS OF OHIO AND INDIANA.
TRAILING STRATIFORM PRECIPITATION WITH EMBEDDED LIGHTNING WILL
IMPACT THE SOUTHERN TERMINALS OMITTENLY DURING THE FIRST HOUR OR TWO
OF THE TAF CYCLE. RESIDUAL MOISTURE WITH ONSET OF LOW LEVEL COLD AIR
ADVECTION SHOULD ALLOW IFR STRATUS DECK TO FILL IN ACROSS THE
NORTHERN HALF OF THE AREA. OBSERVING PLATFORMS HAVE RECORDED THE IFR
CIGS NOW ITS A QUESTION OF OVERALL DEVELOPING COVERAGE. KEPT CIGS AT
BORDERLINE IFR/MVFR FOR THE DETROIT TERMINALS. DEVELOPING BOUNDARY
LAYER TODAY WILL LEAD TO WEST WINDS OF 10 TO 20 KNOTS. LOSS OF
DAYTIME HEATING AND DRY AIR ADVECTION IS EXPECTED TO LEAD TO
PREDOMINATELY SKC CONDITIONS TONIGHT.

//DTW THRESHOLD PROBABILITIES...

* MEDIUM IN ISOLATED CLOUD TO GROUND LIGHTNING STRIKES BETWEEN 06-
  08Z.

* HIGH FOR CIGS BELOW 5000 FT AGL. LOW CONFIDENCE IN POTENTIAL FOR
  CIGS OF LESS THAN 1000 FT.

&&

.PREV DISCUSSION...ISSUED 325 PM EDT SUN AUG 2 2015

SHORT TERM...THIS AFTERNOON AND TONIGHT

SCATTERED CONVECTION CONTINUES TO BUBBLE OVER FAR NORTHERN CWA ALONG
WEST TO EAST OUTFLOW BOUNDARY STALLED OVER THAT AREA ALONG SOUTHERN
PERIPHERY OF CONVECTIVE CLUSTER TRACK(S) FROM THIS MORNING AND EARLY
AFTERNOON. EXPECT THIS ACTIVITY TO GRADUALLY INCREASE IN COVERAGE
THROUGH THE REST OF THE AFTERNOON...AT LEAST NORTH OF THE INTERSTATE
69 CORRIDOR. GIVEN THE DEGREE OF INSTABILITY ADVECTING INTO AREA FROM
THE WEST AND SOUTHWEST AND FEEDING THIS ACTIVITY...EXPECT SOME OF
THESE STORMS TO BE SEVERE. TO THIS POINT...THIS ACTIVITY HAS HAS
REMAIN CONFINED TO THE SAGINAW VALLEY AND NORTHERN THUMB. IF THIS
REMAINS THE CASE...LATER ACTIVITY THIS EVENING SHOULD HAVE A
STRAIGHT SHOT INTO THE AREA WITHIN TOO MUCH IMPEDANCE FROM
STABILIZATION IN THE WAKE OF THIS LEAD CLUSTER OF SEVERE STORMS.

THIS MAIN WIDESPREAD ACTIVITY...WHICH WILL SPREAD SOUTHWARD THROUGH
THE AREA THIS EVENING...STILL LOOKS TO ORGANIZE FROM VARIOUS
CONVECTIVE CLUSTERS CURRENTLY ACTIVE OVER NORTHERN WISCONSIN AND
WESTERN NORTHERN LOWER MICHIGAN. AS A COLD FRONT AND STRONG UPPER
LEVEL SUPPORT FROM AMPLIFYING UPPER TROUGH WORK INTO THE
REGION...THESE CLUSTERS SHOULD COMBINE INTO A PRETTY SOLID LINE (OR
TWO) OF STORMS AND ACCELERATE THROUGH SOUTHEAST LOWER MICHIGAN FROM
MID TO LATE EVENING. WHILE LATE DAY INSTABILITY...CURRENTLY 2500
J/KG OF MLCAPE...WILL EASE BY THIS TIME...HIGH BULK SHEAR FROM
STRONG WIND FIELD...ALONG WITH GENERAL UPSCALE ORGANIZATION OF THE
MESOSCALE SYSTEM...SHOULD SUPPORT RATHER WIDESPREAD WIND DAMAGE.

AS OF 3 PM...IT APPEARS THE STORM CLUSTER THAT WILL LIKELY BECOME
OUR MAIN EVENT THIS EVENING IS ORGANIZING OVER NORTHERN WISCONSIN AS
THE FULL UPPER SUPPORT OF THE DEEPENING SHORTWAVE TROUGH IS NOW
SPREADING INTO THIS AREA. THIS CURRENT LOCATION SUPPORTS A SLIGHTLY
FASTER ADVANCE INTO THE AREA BY PERHAPS 1 OR 2 HOURS -VS- THE
PREVIOUS FORECAST THINKING. THIS BASICALLY FOCUSES THIS NEXT ROUND
OF SEVERE THUNDERSTORMS AT 23Z-00Z OVER THE FAR NORTHERN CWA TO 01Z-
02Z FLINT INTO NORTHERN METRO DETROIT...AND QUICKLY SOUTH FROM THERE
THE REST OF THE EVENING AS WHAT WILL MOST LIKELY BE A FORWARD
PROPAGATING MCS MATURES AND RACES THROUGH LOWER MICHIGAN.

LONG TERM...

UPPER LOW CENTER WILL SLOWLY TRACK FROM ONTARIO TO QUEBEC MONDAY AND
TUESDAY. THIS WILL KEEP THE NORTHERN AND CENTRAL GREAT LAKES
CONFINED WITHIN COOLER WEST TO NORTHWEST FLOW AROUND THE BACKSIDE OF
THE SYSTEM. COOLER AND QUIETER WEATHER CAN BE EXPECTED FOR THE FIRST
PART OF THE WORK WEEK...ALTHOUGH A FEW SHORTWAVE TROUGHS WILL STILL
PIVOT DOWN ACROSS MICHIGAN. MODELS ARE STILL KEYING IN ON A
SECONDARY COLD FRONT DROPPING DOWN THROUGH NORTHERN AND CENTRAL
LOWER MICHIGAN LATE MONDAY THROUGH THE FIRST PART OF MONDAY NIGHT.
FORECAST CONTINUES TO CARRY A LOW CHANCE OF POPS FROM I-69 NORTH
WHERE MORE MOISTURE WILL BE AVAILABLE AND WHERE COOLER MID-LEVEL AIR
WILL OVERLAP WITH DIURNAL HEATING AHEAD OF THE FRONT. THE SECONDARY
FRONT WILL REMAIN SETTLED OVER CENTRAL MICHIGAN INTO TUESDAY...AND
MAY AGAIN PROVIDE A FOCUS FOR SHOWERS AND A FEW THUNDERSTORMS
TUESDAY AFTERNOON/EVENING AS A SHORTWAVE TROUGH CLIPS ACROSS THE
REGION. CONDITIONS WILL FEEL COOLER WITH DEWPOINTS DROPPING INTO
MORE COMFORTABLE READINGS IN THE 50S...AND AS DAYTIME HIGHS ONLY
REACH INTO THE MID 70S TO LOW 80S MONDAY AND INTO THE 70S ON TUESDAY.

WEDNESDAY THROUGH SUNDAY.

FAIR WEATHER IS STILL ON TRACK FOR WEDNESDAY AS HIGH PRESSURE MOVES
OVER THE REGION. DRY CONDITIONS SHOULD HOLD OVER MOST OF SOUTHEAST
MICHIGAN ON THURSDAY MORNING...WITH EXCEPTION OF THE SOUTHERN MOST
COUNTIES WHERE SCATTERED SHOWERS WILL BEGIN TO POP. CHANCES OF
SHOWERS AND THUNDERSTORMS WILL SPREAD NORTHWARD THROUGH THE
AFTERNOON AND EVENING OFF LOW PUSHING INTO NORTHERN OHIO. CONFIDENCE
AND TIMING ON THIS SYSTEM IS LOW TO MODERATE DUE TO MODEL
INCONSISTENCIES. POTENTIAL FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL LINGER INTO SATURDAY.

MARINE...

STRONG SOUTHWEST WINDS WITH GUSTS OF 25 TO 30 KNOTS WILL CONTINUE
INTO TONIGHT IN ADVANCE OF A COLD FRONT DROPPING THROUGH THE GREAT
LAKES. THE STRONGEST WINDS WILL BE OVER SAGINAW BAY...WHERE
SOUTHWEST WINDS WILL FUNNEL. THE FRONT AND A WARM AND UNSTABLE
AIRMASS PRECEDING IT WILL ALSO PROVIDE ROUNDS OF SHOWERS AND
THUNDERSTORMS THROUGH TONIGHT...SOME OF WHICH WILL BE SEVERE. THE
MOST LIKELY THREAT WITH THUNDERSTORMS WILL BE WIND GUSTS TO 50
KNOTS. WINDS WILL TURN WEST AND THEN NORTHWEST BEHIND THE FRONT
MONDAY. WIND SPEEDS MONDAY LOOK TO BE GREATEST OVER NORTHERN LAKE
HURON...WHERE THEY WILL REACH BETWEEN 15 TO 25 KNOTS MONDAY NIGHT
THROUGH TUESDAY NIGHT AS COOLER AIR SETTLES OVER THE CENTRAL GREAT
LAKES REGION.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR LHZ421-
     422-441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR LEZ444.

&&

$$

AVIATION.....CB
SHORT TERM...DG
LONG TERM....HLO/DE
MARINE.......HLO


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



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