Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 012230
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
630 PM EDT FRI MAY 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 315 PM EDT FRI MAY 1 2015

FAIR WEATHER WILL CONTINUE INTO SUNDAY EVENING WHEN A COLD FRONT
WILL BRING SOME SHOWERS AND THUNDERSTORMS. THE FRONT WILL STALL
CLOSE BY LOWER MICHIGAN AND BRING CHANCES FOR RAIN AT TIMES
THROUGH NEXT WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 315 PM EDT FRI MAY 1 2015

ONLY FORECAST ISSUE IN THE NEAR TERM IS TIMING AND AMOUNT OF
PRECIP ON SUNDAY NIGHT. NO SIGNIFICANT CHANGES WERE MADE TO THE
FORECAST BEFORE THEN ALTHOUGH MINS TONIGHT AND MAXES ON SATURDAY
WERE TWEAKED SLIGHTLY AS THE VERY DRY ATMOSPHERE SUGGESTS MINS A
BIT BLO GUIDANCE AND MAXES A BIT ABOVE GUIDANCE ON SATURDAY.

RETURN FLOW SETS UP SATURDAY NIGHT SUNDAY AS SFC RIDGING MOVES
EAST...BUT IT WILL TAKE A WHILE FOR MOISTURE TO ARRIVE. BY SUNDAY
EVENING GOOD MOISTURE TRANSPORT AND A 35 TO 40 KT LLJ ARRIVES
AHEAD OF APPROACHING COLD FRONT. THERE IS ALSO ENOUGH MID LEVEL
INSTABILITY FOR SOME THUNDER TO BE EMBEDDED IN THE AREA OF RAIN.

AS FOR TIMING... CONSENSUS FROM THE 12Z GUIDANCE IS THAT THE RAIN
ARRIVES ACROSS THE NORTHWEST FORECAST AREA SUNDAY EVENING AND
SLOWLY PROGRESSES EASTWARD...NOT REACHING THE EXTREME SE CWA UNTIL
AROUND 12Z ON MONDAY.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 315 PM EDT FRI MAY 1 2015

MILD WEATHER IS ANTICIPATED THROUGH MOST OF THE LONG RANGE FORECAST
PERIOD WITH POTENTIAL FOR SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH MOST OF THE WEEK.

A WEAK COLD FRONT WILL BRING POTENTIAL FOR SOME SCATTERED SHOWERS
AND THUNDERSTORMS ON MONDAY. THIS BOUNDARY WILL STALL OUT TO THE
SOUTH OF LOWER MI MONDAY NIGHT INTO TUESDAY. HOWEVER THE BOUNDARY
WILL REMAIN IN CLOSE ENOUGH PROXIMITY TO OUR AREA TO POTENTIALLY
FOCUS DEVELOPMENT OF MORE SCATTERED SHOWERS AND STORMS ON TUESDAY.
THE SEVERE WX THREAT FOR MONDAY THROUGH TUESDAY IS VERY LOW DUE TO
WEAK INSTABILITY AND LIMITED MOISTURE WITH SFC DEW POINTS ONLY
EXPECTED TO REACH THE 40S TO LOWER 50S.

THE BOUNDARY WILL MOVE THROUGH AS A WARM FRONT FOR MIDWEEK WITH
PERSISTENT SOUTHERLY FLOW WARM AIR ADVECTION TO FOLLOW RESULTING IN
ABOVE NORMAL TEMPERATURES AND A GRADUAL INCREASE IN MOISTURE. THERE
IS A CHANCE FOR A SCATTERED SHOWER OR THUNDERSTORM AT JUST ABOUT
ANYTIME MID TO LATE NEXT WEEK BUT DRY WX SHOULD PREVAIL MOST OF THE
TIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 629 PM EDT FRI MAY 1 2015

SOLID VFR CONDITIONS ARE EXPECTED INTO SUNDAY FOR ALL OF OUR TAF
SITES. A DISSIPATING FRONTAL SYSTEM MOVING THROUGH THE AREA
TONIGHT HAS RESULTED IN AN AREA OF THICK CIRRUS CLOUDS THESE
CLOUDS WILL LINGER INTO SATURDAY MORNING AS THE FRONTAL SYSTEM
CONTINUES TO DISSIPATE. I WOULD EXPECT MOSTLY CLEAR SKIES BY MIDDAY
SATURDAY ACROSS THE AREA. WINDS WILL BE TURN TO THE SOUTHWEST BY
EARLY SATURDAY MORNING AT THE TAF SITES AND WILL CONTINUE TO LIGHT
OUT OF THE SOUTHWEST SATURDAY.

&&

.MARINE...
ISSUED AT 315 PM EDT FRI MAY 1 2015

WINDS AND WAVES WILL BE RELATIVELY LIGHT INTO EARLY SATURDAY AS
HIGH PRESSURE PREVAILS. WILDS WILL GO SOUTH AND INCREASE ON
SATURDAY AS THE HIGH MOVES EAST AND A COLD FRONT APPROACHES.
THUNDERSTORMS SHOULD HOLD OFF UNTIL SUNDAY EVENING.


&&

.HYDROLOGY...
ISSUED AT 315 PM EDT FRI MAY 1 2015

RIVERS ARE RUNNING NEAR TO BELOW NORMAL AND NO ISSUES ARE EXPECTED
THROUGH THE WEEKEND. PERIODS OF RAIN AND THUNDERSTORMS DURING THE
FIRST HALF OF NEXT WEEK MAY LEAD TO SOME LOCATIONS RECEIVING AN INCH
OR MORE OF RAINFALL. WITH THE RECENT DRY WEATHER AND THE GREEN-UP
UNDERWAY... THIS WATER IS LIKELY TO BE ABSORBED BY SOIL... PLANTS...
AND RIVERS WITH NO NEGATIVE CONSEQUENCE.

&&

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

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...WDM
HYDROLOGY...CAS
MARINE...OSTUNO





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