Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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402
FXUS63 KGRR 020730
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
236 AM EDT MON MAY 2 2016

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE

.SYNOPSIS...
ISSUED AT 236 AM EDT MON MAY 2 2016

LOW PRESSURE MOVING ACROSS OHIO WILL QUICKLY MOVE EAST TO
PENNSYLVANIA TODAY AND RAIN WILL END THIS MORNING AND THEN SKIES
WILL BECOME PARTLY SUNNY. A COLD FRONT WILL MOVE THROUGH TUESDAY
NIGHT BRINING ANOTHER CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORM
ALONG WITH COOLER AIR FOR WEDNESDAY. A WARMING TREND IS EXPECTED FOR
MOTHERS DAY WEEKEND WITH HIGHS AROUND 70.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 236 AM EDT MON MAY 2 2016

FORECAST CONCERNS ARE MINIMAL TODAY AND MAINLY DEAL WITH PCPN TRENDS
THIS MORNING AND THE COLD FRONT TUESDAY NIGHT.

LATEST RADAR LOOP SHOWS PCPN MOVING EAST AND DIMINISHING. MUCH OF
THE PCPN SHOULD BE OVER BY 12Z LEAVING MOSTLY CLOUDY SKIES.
SATELLITE IMAGERY THOUGH SHOWS CLEAR SKIES ACROSS NORTHERN LOWER. AS
WINDS BECOME NORTHERLY BEHIND THE DEPARTING LOW...WE SHOULD SEE SOME
DRIER AIR FROM THE NORTH MOVE SOUTH AND MIX OUT THE CLOUDS. TEMPS
WILL FALL INTO THE UPPER 30S TONIGHT...PROBABLY JUST WARM ENOUGH TO
PRECLUDE FROST ACROSS THE SOUTHERN CWA.

THE NEXT COLD FRONT IS WELL HANDLED BY THE SHORT RANGE MODELS AND
SHOULD MOVE SOUTH ACROSS THE CWA TUESDAY NIGHT. MODELS SHOW SOME
WEAKNESS IN THE STABILITY FIELD AND THETA-E DECREASING WITH HEIGHT.
THIS WE INCLUDED A MENTION OF THUNDER TUESDAY NIGHT. A DEEP UPPER
TROUGH DROPPING SOUTH ACROSS THE GREAT LAKES WILL LIKELY PREVENT THE
PCPN FROM ENDING QUICKLY ON WEDNESDAY...SO DESPITE THE PASSAGE OF
THE COLD FRONT SHOWERS WILL LINGER THROUGH WEDNESDAY. A CHILLY DAY
IS EXPECTED WEDNESDAY WITH HIGHS IN THE 50S.


.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 236 AM EDT MON MAY 2 2016

UPPER TROUGH WILL LINGER OVERHEAD THROUGH THURSDAY BUT THE MAIN
UPPER LOW WILL MOVE AWAY TO THE SOUTHEAST TOWARD THE CAROLINAS. A
FEW SHOWERS WILL STILL BE POSSIBLE WEDNESDAY NIGHT AND THURSDAY BUT
OVERALL COVERAGE SHOULD BE LESS THAN ON WEDNESDAY... AND MAINLY
NEAR/EAST OF HIGHWAY 131.

FRIDAY LOOKS TO BE THE BEST DAY IN THE LONG TERM PERIOD AS RIDGING
AND WARM AIR ADVECTION SLIDE IN FROM THE NORTHWEST. HIGH CONFIDENCE
FOR MOSTLY SUNNY SKIES WITH HIGHS NEAR 70 EXCEPT AT THE LK MI COAST.

MUCH OF SATURDAY SHOULD BE DRY/WARM TOO WITH HIGHS 70-75... BUT A
FRONTAL BOUNDARY WILL BE DROPPING IN FROM THE NORTHWEST LATE IN THE
DAY IN RESPONSE TO NRN STREAM TROUGH DIGGING INTO THE NRN GRTLKS RGN.
THIS MAY LEAD TO A BATCH OF LATE DAY CONVECTION WHICH CONTINUES INTO
SATURDAY NIGHT.

PRESENT INDICATIONS ARE THAT THE SFC FRONT WILL SLIP SOUTH OF THE
AREA FOR SUNDAY. RESULT SHOULD BE FOR SCATTERED MORNING SHOWERS
ENDING FOLLOWED BY A DECREASING CLOUD TREND AND SLIGHTLY COOLER MAX
TEMPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1132 PM EDT SUN MAY 1 2016

IFR IMPACTS CONTINUE MAINLY OVER SOUTHERN LOWER MI. RADAR COMBINED
WITH OBSERVATIONS INDICATE THAT THE RISK FOR THUNDERSTORMS WILL
NEAR THE SOUTHERN TAF SITES KAZO...KBTL AND KJXN. I ADDED THIS
RISK EARLIER. THE LOW LEVEL MOISTURE REMAINS HIGH FOR THESE TAFS
SITES TONIGHT...THUS I MAINTAINED THE IFR RISK THROUGH DAYBREAK.

NORTHERLY WINDS WILL DEVELOP ON MONDAY. THIS WILL DRAW DOWN A
DRIER AIRMASS DURING THE DAY. THUS CONDITIONS ARE FORECASTED TO
RETURN TO VFR FOR ALL SITES.


&&

.MARINE...
ISSUED AT 330 AM EDT MON MAY 2 2016

WINDS WILL SHIFT FROM THE NORTHEAST TO THE NORTH TODAY. WIND SPEEDS
IN THE 10 TO 20 MPH RANGE WILL RESULT IN WAVES IN THE 1 TO 3 FOOT
RANGE.

&&

.HYDROLOGY...
ISSUED AT 205 PM EDT SUN MAY 1 2016

FLOODING IS NOT EXPECTED. RECENT RAINS HAVE RESULTED IN MODEST RISES ON RIVERS
AND STREAMS... BUT SIGNIFICANT RISES ON MAIN STEM RIVERS ARE NOT EXPECTED.
ADDITIONAL RAINFALL IS EXPECTED TONIGHT ACROSS SOUTHERN LOWER MICHIGAN. A
QUARTER TO HALF INCH OF RAIN IS POSSIBLE THROUGH MONDAY MORNING ACROSS THE
KALAMAZOO RIVER BASIN AND THE UPPER GRAND BASIN.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...MJS
HYDROLOGY...EBW
MARINE...04



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