Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 032228 AAB
AFDGRR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
628 PM EDT TUE MAY 3 2016

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 PM EDT TUE MAY 3 2016

A COOLER SHOWERY PERIOD IS EXPECTED BEGINNING TONIGHT THROUGH
WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM AFFECTS THE AREA. A COLD
FRONT WILL DROP INTO SOUTHWEST LOWER MICHIGAN FROM THE NORTH TONIGHT
AND PUSH EAST OF THE AREA ON WEDNESDAY. THE FRONT WILL BE
ACCOMPANIED BY SHOWERS AND POSSIBLY A FEW THUNDERSTORMS
TONIGHT...WITH SHOWERS LINGERING FOR WEDNESDAY AND WEDNESDAY NIGHT.
WE SHOULD DRY OUT FOR THE END OF THE WORK WEEK ON THURSDAY AND
FRIDAY. HIGHS ON WEDNESDAY WILL ONLY TOP OUT IN THE 50S...WARMING TO
AROUND 60 ON THURSDAY AND NEAR 70 ON FRIDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 328 PM EDT TUE MAY 3 2016

MAIN FORECAST FOCUS IS ON THE CHANCES FOR RAIN WITH THE SYSTEM SET
TO AFFECT THE AREA TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. RAIN
SHOWERS WILL SLOWLY SPREAD SOUTH AND EAST INTO SOUTHWEST LOWER
MICHIGAN TONIGHT. THE THREAT FOR THUNDER LOOKS LIMITED WITH MEAGER
LOW LEVEL MOISTURE VALUES IN REGARD TO CHANCES FOR THUNDER. LEFT THE
MENTION OF A CHANCE OF THUNDERSTORMS IN THE FORECAST...BUT THINKING
IF IT OCCURS IT WILL BE QUITE ISOLATED. THE CONVECTION ALLOWING
MODELS ARE NOT VERY BULLISH ON STORMS AND THIS MAKES SENSE GIVEN
850MB DEW POINTS THAT ARE SUB +8C AND SURFACE DEW POINTS IN THE 30S
AND 40S F.

THE UPPER LOW REMAINS OVERHEAD BOTH WEDNESDAY AND WEDNESDAY NIGHT
WHICH WILL LEAD TO CONTINUED CHANCES FOR SHOWERS. THINKING ANY
THUNDER CHANCE WEDNESDAY AND WEDNESDAY NIGHT IS ALMOST ZERO...SO
LEFT IT OUT OF THE FORECAST. TEMPERATURES WEDNESDAY AFTERNOON WILL
BE QUITE COOL IN THE 40S TO LOW 50S. WE WILL BE WELL BELOW NORMAL
HIGHS...WHICH ARE UP IN THE MID 60S THIS TIME OF YEAR.

THURSDAY AND THURSDAY NIGHT WE LOOK AS IF WE WILL CLEAR OUT WITH DRY
WEATHER FORECAST. A RIDGE OF HIGH PRESSURE WILL BE SITUATED THROUGH
THE REGION.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 328 PM EDT TUE MAY 3 2016

SEASONABLY MILD TEMPERATURES ARE ANTICIPATED FOR MOST OF THE LONG
RANGE FCST PERIOD. FAIR WEATHER WILL CONTINUE FRIDAY THROUGH FRIDAY
NIGHT WITH SEASONABLY MILD TEMPERATURES. A COLD FRONT MOVING IN FROM
THE NW WILL BRING A CHANCE OF SHOWERS AND PERHAPS SOME THUNDERSTORMS
ON SATURDAY. IT IS NOTED THAT OVERALL MEDIUM RANGE GUIDANCE TRENDS
ARE INDICATING A FASTER FRONTAL PASSAGE AND SUBSEQUENT EARLIER
ARRIVAL OF PCPN SATURDAY.

THE FRONT SHOULD BE THROUGH OUR FCST AREA BY SATURDAY EVENING AND A
COOLER AIRMASS WILL BRIEFLY ADVECT IN FOR SUNDAY AS CANADIAN HIGH
PRESSURE BUILDS IN. TEMPERATURES WILL MODERATE AGAIN EARLY NEXT WEEK
AS SOUTHERLY RETURN FLOW DEVELOPS ON THE BACK SIDE OF THE DEPARTING
RIDGE. THE PERSISTENT SOUTH FLOW WILL ALSO LEAD TO GRADUALLY
INCREASING MOISTURE AND POTENTIAL FOR SOME SHOWERS LATE MONDAY
THROUGH TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM EDT TUE MAY 3 2016

LOW LEVEL MOISTURE WILL BE ON THE INCREASE TONIGHT INTO WEDNESDAY
AS A LOW PRESSURE SYSTEM MOVES IN. SOME OF THE MOISTURE WILL BE
FROM THE GREAT LAKES. THIS WILL RESULT IN CEILINGS LOWERING...AND
RAIN ARRIVING. IFR IMPACTS LOOK LIKELY FOR ALL TAF SITES AT TIMES
LATE TONIGHT OR ON WEDNESDAY. IN ADDITION THE RAIN COULD CAUSE THE
VISIBILITIES TO FALL INTO MVFR OR LOWER LEVELS.

THIS SYSTEM WILL REMAIN IN THE AREA THROUGH WEDNESDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 328 PM EDT TUE MAY 3 2016

OPTED TO ISSUE A SMALL CRAFT ADVISORY BEGINNING TONIGHT AND LASTING
INTO THE AFTERNOON ON THURSDAY. SOUTHWESTERLY WINDS WILL INCREASE
TONIGHT AND MAY PUSH WAVES TOWARDS SCA CRITERIA. THE MAIN WIND/WAVE
EVENT HOWEVER WILL COME ON WEDNESDAY AND WEDNESDAY NIGHT WHEN STRONG
NORTHERLY COLD AIR ADVECTION KICKS IN. WINDS WILL PUSH INTO THE 20-
30 KNOT RANGE OUT OF THE NORTH WHICH WILL BUILD WAVES INTO THE 5 TO
8 FOOT RANGE.

WINDS BECOME LIGHTER THURSDAY NIGHT INTO FRIDAY AS A RIDGE OF HIGH
PRESSURE MOVES THROUGH THE REGION.


&&

.HYDROLOGY...
ISSUED AT 1220 PM EDT TUE MAY 3 2016

RIVER FLOOD ADVISORIES ARE CURRENTLY POSTED FOR SYCAMORE CREEK NEAR
HOLT AND THE GRAND RIVER AT IONIA. SYCAMORE CREEK IS FALLING AND
SHOULD FALL BELOW BANKFULL BY WEDNESDAY. THE GRAND RIVER IS STILL
RISING AT IONIA AND SHOULD CREST WEDNESDAY.

RAINFALL TOTALS TONIGHT THROUGH WEDNESDAY WILL BE A QUARTER TO A
HALF INCH. THIS SHOULD HELP TO KEEP RIVER LEVELS ELEVATED.
THUNDERSTORMS ARE POSSIBLE LATE SATURDAY INTO SATURDAY NIGHT... SO
RIVERS WILL NEED TO BE MONITORED INTO EARLY NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 AM WEDNESDAY TO 2 PM EDT THURSDAY
     FOR LMZ844>849.

&&

$$

SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...DUKE
AVIATION...MJS
HYDROLOGY...63
MARINE...DUKE



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