Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 201929
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
329 PM EDT MON APR 20 2015

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

.SYNOPSIS...
ISSUED AT 330 PM EDT MON APR 20 2015

A STALLED STORM SYSEM OVER THE NORTHERN GREAT LAKES WILL KEEP
SHOWERS AND UNSEASONABLY COLD WEATHER THROUGH A GOOD PART OF THIS
WEEK. THE SHOWERS MAY BE MIXED WITH SNOW OR TURN TO SNOW AT TIMES
TUESDAY NIGHT INTO THURSDAY. ANY ACCUMULATIONS WILL BE MINOR.
FREEZING TEMPERATURES ARE EXPECTED EACH MORNING STARTING ON
WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 330 PM EDT MON APR 20 2015


THE MAIN ISSUE IS THE PRECIPITATION THREAT AND RISK OF SNOW
TUESDAY NIGHT INTO WEDNESDAY NIGHT. OUR STALLED LOW PRESSURE
SYSTEM WILL CONTINUE BRING COLDER AIR INTO THE REGION INTO
WEDNESDAY. SHORTWAVES ROTATING AROUND THE STALLED SYSTEM WILL KEEP
SHOWERS GOING THROUGH THE SHORT TERM. WITH THE LAKE TEMPERATURE
NEAR 3C... AND 850 TEMPS FALLING TO NEAR -8C.... THAT IS MARINGAL
FOR LAKE EFFECT BUT GIVEN THERE IS ENOUGH MOISTURE IN THE 950 TO
700 MB LAYER THROUGH THIS TIME PERIOD SHOWERS WILL CONTINUE AS
WELL AS GUSTY WINDS. BY TUESDAY NIGHT IT GETS COLD ENOUGH FOR
MIXER RAIN AND SNOW AND THAT THREAT CONTINUES INTO WEDNESDAY
NIGHT.




.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 330 PM EDT MON APR 20 2015

UNSEASONABLY COOL WEATHER WILL CONTINUE THURSDAY WITH THE UPPER
TROUGH AXIS IN PLACE OVER THE EASTERN GREAT LAKES REGION AND DEEP
CYCLONIC FLOW. SCATTERED RAIN SHOWERS WILL LINGER THURSDAY AND MAY
BE MIXED AT TIMES WITH WET SNOW FLAKES PARTICULARLY ACROSS HIGHER
ELEVATIONS OF OUR NORTHERN FCST AREA.

THE UPPER TROUGH WILL SHIFT FURTHER EAST THURSDAY NIGHT AS A SFC
RIDGE BEGINS TO BUILD IN. THIS WILL LIKELY SET THE STAGE FOR A
COLDER NIGHT DEPENDING ON EXTENT AND TIMING OF CLEARING AS THE RIDGE
BEGINS TO BUILD IN. THERE IS POTENTIAL FOR WIDESPREAD TEMPS IN THE
25 TO 30 DEGREE RANGE BY EARLY FRIDAY MORNING SO FROST/FREEZE ISSUES
ARE CERTAINLY A CONCERN FOR LATE WEEK.

THE SFC HIGH PRESSURE RIDGE WILL BRING FAIR BUT COOL WEATHER FRIDAY
INTO SATURDAY. MAX TEMPS BY FRIDAY SHOULD REACH THE UPPER 40S TO
LOWER 50S WITH MIN TEMPS FRIDAY NIGHT IN THE 20S TO AROUND 30
DEGREES. TEMPERATURES WILL UNDERGO A SLOW MODERATING TREND FOR THE
WEEKEND INTO EARLY NEXT WEEK WITH FAIR WX EXPECTED TO CONTINUE WITH
THE SFC RIDGE REMAINING IN CONTROL OF THE WX PATTERN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1220 PM EDT MON APR 20 2015

MAINLY IFR/MVFR CONDITIONS WILL CONTINUE THROUGH MID TO LATE
AFTERNOON DUE TO LOW CIGS AND SCATTERED SHOWERS AND PATCHY FOG
BEFORE GRADUALLY IMPROVING TO VFR THIS EVENING AND OVERNIGHT.

IT WILL BE BREEZY THIS AFTERNOON WITH SW WINDS OF 15 TO 25 KTS WITH
GUSTS TO AROUND 30 KTS. SOUTHWEST TO WEST WINDS WILL STAY UP AROUND
15 TO 25 KTS OVERNIGHT AND THEN VEER TO THE WEST AND INCREASE TO 20
TO 25 KTS WITH GUSTS TO AROUND 30 KTS BY MID TO LATE TUESDAY MORNING.

SCATTERED LIGHT RAIN SHOWERS WILL LINGER OVERNIGHT AND THEN BECOME
MORE PREVALENT ON TUESDAY. MAINLY VFR CONDITIONS ARE ANTICIPATED
TUESDAY ALTHOUGH SOME PATCHY MVFR IS POSSIBLE DUE TO LOWER CIGS AND
HEAVIER SHOWERS.


&&

.MARINE...
ISSUED AT 330 PM EDT MON APR 20 2015

I EXTENTED THE AREA COVERED BY THE SCA TO COVER THE ENTIRE NEAR
SHORE. I ALSO CONTINUED IT THROUGH WEDNESDAY AFTERNOON. WITH OUR
SYSTEM STALLED OVER THE GREAT LAKES MOST OF THE WEEK WE WILL SEE A
CONTINUATION OF 15 TO 25 KNOT WINDS FROM THE SOUTHWEST INTO
TUESDAY THEN NORTHWEST TUESDAY NIGHT THROUGH A GOOD PART OF THE
REST OF THE WEEK.

&&

.HYDROLOGY...
ISSUED AT 1156 AM EDT MON APR 20 2015

WIDESPREAD RAINFALL THROUGH 8 AM THIS MORNING PRODUCED 0.50 TO 0.75
INCHES ACROSS MOST OF THE GRAND AND MUSKEGON RIVER BASINS. FURTHER
SOUTH ACROSS THE KALAMAZOO RIVER BASIN...RAINFALL AMOUNTS WERE
HIGHER IN THE 0.75 TO 1.00 INCH RANGE. AS EXPECTED...GRADUAL RIVER
RISES HAVE BEGUN ON MOST AREA RIVERS. GENERAL HYDRO THINKING HAS NOT
CHANGED MUCH...MOSTLY WITHIN BANK RISES ARE EXPECTED. A FEW SITES
COULD EXCEED BANKFULL. BUT WITH RAIN TODAY AND TONIGHT BEING OF THE
SCATTERED AND LIGHT VARIETY...SIGNIFICANT FLOODING IS NOT EXPECTED.

FORECAST RAINFALL TODAY AND TONIGHT IS IN THE 0.10 TO 0.25 INCH
RANGE. EVEN LIGHTER PRECIP AMOUNTS ARE EXPECTED TUESDAY
INTO WEDNESDAY. A SLIGHT CHANCE OF LIGHT RAIN AND SNOW WILL LINGER
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. BUT MAINLY DRY AND CHILLY
WEATHER IS EXPECTED TOWARD THE END OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR LMZ844>849.

&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW
MARINE...WDM






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