Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 260355
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1155 PM EDT SAT APR 25 2015


.AVIATION...

SOUTHEAST MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF DRY
NORTHEASTERLY FLOW TONIGHT AS WEAK SURFACE RIDGING BUILDS IN.  THIS
WILL ENSURE A MOSTLY CLEAR SKY BELOW 10K FT THROUGH THIS TIME.
PERSISTENT NORTHERLY FLOW WILL RETAIN VFR CONDITIONS THROUGHOUT
SUNDAY.  A POCKET OF MOISTURE ROTATING THROUGH THE RIDGE PERIPHERY
WILL LEAD TO AN INCREASE IN DIURNAL STRATOCU BY EARLY AFTERNOON.

//DTW THRESHOLD PROBABILITIES...

* LOW IN CEILINGS AT OR BELOW 5000 FEET SUNDAY AFTERNOON AND EVENING.

&&

.PREV DISCUSSION...ISSUED 340 PM EDT SAT APR 25 2015

SHORT TERM...THIS AFTERNOON AND TONIGHT

SHORTWAVE OVER THE MID MISSISSIPPI VALLEY WILL EDGE EASTWARD AND
CONTINUE TO PROVIDE FGEN FORCING INTO THE OHIO VALLEY. WHILE MOST OF
THE LIFT...AND RESULTANT RAIN SHOWERS...WILL REMAIN SOUTH OF THE
AREA INTO THIS EVENING...A FEW SHOWERS WILL BE POSSIBLE OVER THE FAR
SOUTHERN CWA...WELL SOUTH OF METRO DETROIT.

ANY SHOWERS WILL SETTLE SOUTHWARD DURING THE COURSE OF THE EVENING
WITH MOSTLY CLOUDY SKIES ALSO GRADUALLY CLEARING OUT OVER THE SOUTH
HALF OF THE CWA. THIS WILL ALLOW FOR DECENT RADIATIONAL COOLING AND
BRING LOWS BACK WELL INTO THE 30S OVERNIGHT...EVEN AS MODEST
NORTHEAST FLOW IN THE 5 TO 10 MPH RANGE PERSIST DURING THE OVERNIGHT
HOURS.

LONG TERM...SUNDAY THROUGH NEXT SATURDAY

WATER VAPOR IMAGERY SHOWS SEVERAL PIECES OF SHORTWAVE ENERGY
ROTATING AROUND THE LARGE UPPER LOW CENTERED OFF THE COAST OF MAINE.
TWO OF THESE WAVES...ONE NEAR ST JAMES BAY AND ONE OVER NEWFOUNDLAND
WILL PIVOT DOWN INTO MICHIGAN...THE FIRST ON SUNDAY AND THE SECOND
SUNDAY NIGHT. TIMING HAS BEEN A LITTLE HARD TO PINPOINT HOWEVER
GIVEN MODEL VARIATION WITH HANDLING THESE SMALLER SCALE FEATURES.

WATER VAPOR PRESENTATION OF THE SECOND WAVE OVER NEWFOUNDLAND IN
PARTICULAR IS LOOKING NICE...AND PLUME OF MOISTURE BEING DRAWN OFF
THE ATLANTIC AND AROUND THE NORTH SIDE OF THE LOW CENTER IS ALSO
QUITE APPARENT. MODELS BRING THIS PLUME OF MOISTURE INTO SOUTHEAST
MICHIGAN BY SUNDAY NIGHT AS THE SECOND WAVE ARRIVES...AND HIKE PW
VALUES UP TO JUST OVER 0.5 INCHES. MOISTURE AND FORCING SHOULD
PROVIDE A CHANCE FOR LIGHT RAIN SHOWERS SUNDAY NIGHT INTO MONDAY.
OTHERWISE...HIGH PRESSURE SITUATED OVER THE NORTHERN PLAINS AND
UPPER MIDWEST WILL KEEP FLOW NORTHERLY OVER THE GREAT LAKES...WITH
THE PASSING WAVES HELPING TO REINFORCE COLD AIR. THIS WILL KEEP
TEMPERATURES DOWN BELOW NORMAL BOTH SUNDAY AND MONDAY WITH HIGHS IN
THE 50S. COOLER TEMPS CAN BE EXPECTED CLOSER TO LAKE HURON.

MINIMAL WEATHER CONCERNS FOR THE REMAINDER OF THE PERIOD. BRIEF
RIDGING WILL GIVE WAY TO A WAVE DROPPING SEWD THROUGH THE WESTERN
GREAT LAKES TUESDAY OR WEDNESDAY /12Z SUITE DIFFERS WITH TIMING OF
THIS FEATURE/. REGARDLESS...IMPACTS LOOK TO BE MINIMAL WITH LACK OF
MOISTURE SO KEPT POPS OUT OF THE FORECAST. THIS WAVE WILL ACT TO
DEEPEN THE LONGWAVE EASTERN CONUS TROUGH MIDWEEK TO SOME DEGREE
/AGAIN 12Z SUITE DIFFERS ON THE AMPLITUDE/ LIKELY LEADING TO
NEAR TO SLIGHTLY BELOW NORMAL TEMPS. TREND WILL BE FOR THE RIDGE
OVER THE NORTHERN PLAINS TO SLOWLY EDGE ITS WAY INTO THE WESTERN
GREAT LAKES FROM FRIDAY INTO NEXT WEEKEND...LEADING TO INCREASED
LIKELIHOOD FOR ABOVE NORMAL TEMPS DURING THAT TIME FRAME.

MARINE...

FLOW WILL GRADUALLY TURN FROM NORTHEAST TO MORE NORTHERLY TONIGHT AS
LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY AND HIGH PRESSURE
REMAINS OVER ONTARIO. THE HIGH WILL THEN EXPAND SOUTH AND EAST
THROUGH EARLY NEXT WEEK...KEEPING NORTHERLY FLOW A LITTLE GUSTY
UNTIL MONDAY NIGHT WHEN THE HIGH FINALLY EXPANDS INTO THE CENTRAL
GREAT LAKES. PERSISTENT NORTHERLY FLOW WILL ALLOW WAVE HEIGHTS TO
BUILD AS HIGH AS THREE FEET OVER THE NEARSHORE WATERS OF LAKE HURON
THROUGH MONDAY...EVEN APPROACHING FOUR FEET SUNDAY NIGHT. WAVES UP
TO THREE FEET WILL PERSIST OVER WESTERN LAKE ERIE THIS EVENING
BEFORE WINDS SHIFT MORE NORTHERLY.

&&

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

$$

AVIATION.....MR
SHORT TERM...DG
LONG TERM....HLO/DT
MARINE.......HLO


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



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