Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 241732
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
132 PM EDT SUN APR 24 2016

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT SUN APR 24 2016

THERE WILL BE SCATTERED RAIN SHOWERS NORTH OF I-96 TODAY AND
TONIGHT...WHILE AREAS ALONG AND SOUTH OF I-96 WILL STAY DRY. THE
FRONT RESPONSIBLE FOR THESE SHOWERS WILL SAG SOUTH ON MONDAY AND ALL
OF SOUTHWEST LOWER MICHIGAN WILL SEE SHOWERS AND A FEW
THUNDERSTORMS.  A FEW OF THESE STORMS COULD BE STRONG MONDAY EVENING
SOUTH OF I-96.  THE RAINS WILL BE HEAVIEST INTO MONDAY NIGHT...
BEFORE FINALLY DIMINISHES ON TUESDAY.  MOST AREAS WILL SEE A HALF TO
ONE INCH OF RAIN...ALTHOUGH LOCALLY HIGHER AMOUNTS ARE POSSIBLE.

WE WILL DRY OUT BEFORE THE NEXT CHANCE OF RAIN ARRIVES WEDNESDAY
NIGHT AND THURSDAY.

WE WILL SEE MILD TEMPERATURES OF 65 TO 70 TODAY AND MONDAY...THEN
THE MID WEEK PERIOD SHOULD ONLY SEE DAYTIME HIGHS IN THE 50S.  A
SLIGHT WARM UP IS EXPECTED TOWARD THE END OF THE WEEK WITH 60 TO 65
EXPECTED FOR FRIDAY AND SATURDAY.

&&

.UPDATE...
ISSUED AT 1038 AM EDT SUN APR 24 2016

THE MAIN CHANGES TO THE FORECAST WILL REFLECT A LOWERING OF THE
MAX TEMPS FOR THE NORTHERN HALF OF MY CWA THIS AFTERNOON. ALSO I
DID INCREASE THE POPS FOR THIS AFTERNOON FOR ALL BE THE
SOUTHERNMOST COUNTIES. THE ELEVATED SHOWERS CONTINUE TO DEVELOP
FURTHER SOUTH THAN MOST MODELS INDICATED ACROSS WI. BASED ON
THEIR MOVEMENT...SHOWERS WILL BE ON THE INCREASE FOR SOUTHWEST
LOWER MI THIS AFTERNOON. THIS WILL IMPACT THE TEMPERATURES AS
WELL. WILL CONTINUE TO MONITOR TRENDS...AND MAY NEED TO FURTHER
ADJUST THE FORECAST LATER.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EDT SUN APR 24 2016

A FAIR AMOUNT OF ADJUSTS WERE NEEDED FOR THIS FORECAST PACKAGE AS
THE FRONT IS TRENDING SLOWER AS IT MOVES SOUTH ACROSS THE REGION.
THIS AFFECTS RAIN TIMING AND ALSO TEMPS.

SLOW MOVING SURFACE BOUNDARY WAS TAKING SHAPE EARLY THIS MORNING
ACROSS NORTHERN LAKE MICHIGAN.  THIS SAGS SOUTH INTO THE NORTHERN
CWA BY THE END OF TODAY...BUT THEN BECOMES QUASI-STATIONARY AS LOW
PRESSURE TO THE WEST TRACKS ALONG THE FRONT.  IT NOW APPEARS THAT
THE FRONT WILL NOT PUSH SOUTH OF THE CWA UNTIL THE LOW PASSES LATE
MONDAY NIGHT.

THIS WILL RESULT IN THE RAIN CHANCES REMAINING NORTH OF THE FRONT
TODAY AND TONIGHT...MAINLY NORTH OF A GRAND HAVEN TO ALMA LINE. THIS
WILL BE A STABLE REGIME NORTH OF THE FRONT...SO THUNDER RISK WILL BE
LOW UNTIL CLOSE TO MONDAY MORNING.  PCPN AMOUNTS SHOULD ALSO REMAIN
LOW...GENERALLY UNDER A QUARTER INCH THROUGH DAYBREAK MONDAY.

INTO MONDAY THE FRONT SHOULD SAG VERY SLOWLY SOUTH...PERHAPS JUST A
BIT SOUTH OF I-96 BY THE END OF THE DAY.  THIS SHOULD HELP THE PCPN
TO SAG SOUTH TOO.  ON TOP OF THIS WILL BE A COUPLED JET ARRIVING
OVER THE AREA INCREASING UPPER DIVERGENCE/LIFT.  FEEL THE DAY WILL
GRADUALLY SEE A WIDER PCPN COVERAGE THROUGH THE DAY.  THE BETTER
DYNAMICS SHOULD ALSO INCREASE THE CHANCE FOR THUNDER AS THE FRONT
MOVES INTO BETTER INSTABILITY.  OUTSIDE CHANCE OF SEEING A FEW
STRONGER STORMS SOUTH OF I-96 BY LATE IN THE DAY.  HOWEVER A DECENT
LOW JET IS NOT DEPICTED...SO NOT EXPECTING SIGNIFICANTLY ORGANIZED.

MONDAY NIGHT SHOULD SEE THE STEADIEST RAINS WITH THE SURFACE LOW
PASSING THROUGH.  MOST AREAS SHOULD SEE A HALF TO ONE INCH OF
RAIN BY EARLY TUESDAY...ALTHOUGH LOCALLY HIGHER AMOUNTS MAY OCCUR.

WITH THE FRONT A BIT SLOWER TO EXIT CHANCE POPS WHERE ADDED TO
TUESDAY.  AFTER TEMPS NEAR 70 ON MONDAY...MOST AREAS WILL BE STUCK
IN THE 50S ON TUESDAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM EDT SUN APR 24 2016

LONG TERM PERIOD SHOWS SOMEWHAT CONFLUENT FLOW ALOFT OVER THE GREAT
LAKES...DUE TO BLOCKING OVER EASTERN CANADA. SYSTEMS MOVING OUR
DIRECTION LOOK TO BE LOSING PUNCH AND ARE FORECAST TO PASS BY TO OUR
SOUTH. A LOW WILL MOVE BY TO OUR SOUTH WEDNESDAY NIGHT AND THURSDAY
WITH RAIN SHOWERS...ESPECIALLY ACROSS SOUTHERN LOWER MICHIGAN.
PRECIP WILL BE HEAVIEST TOWARDS I-94. WE DRY OUT BEHIND THIS SYSTEM
FOR THE END OF THE WORK WEEK BEFORE ANOTHER LOW TAKES A SIMILAR
TRACK NEXT WEEKEND. TEMPERATURES LOOK TO BE BELOW NORMAL IN THE 50S
FOR WEDNESDAY AND THURSDAY AND BACK TOWARDS NORMAL AROUND 60 FRIDAY
AND SATURDAY.

BOTTOM LINE FAIRLY TYPICAL SPRING TIME WEATHER ACROSS OUR AREA WITH
PERIODIC SHOWERS AND NEAR TO SLIGHTLY BELOW NORMAL TEMPS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 129 PM EDT SUN APR 24 2016

VFR EXPECTED THROUGH THE PERIOD. A FRONTAL BOUNDARY WILL MOVE FROM
NORTHERN LOWER TO NEAR US-10 BY MONDAY MORNING. SCATTERED SHOWERS
NEAR THE BOUNDARY MAY AFFECT THE NORTHERN TAF SITES. HOWEVER THE
SOUTHERN TAF SITES ARE EXPECTED TO BE DRY.

&&

.MARINE...
ISSUED AT 330 AM EDT SUN APR 24 2016

NO HEADLINES EXPECTED WITH A SE FLOW TODAY AND TONIGHT.  HOWEVER WE
MAY NEED A SMALL CRAFT ADVISORY INTO MONDAY AS THE WINDS BECOME MORE
SOUTHERLY AND INCREASE.  WINDS WILL BECOME NORTHERLY BEHIND A
PASSING FRONT LATE MONDAY NIGHT.


&&

.HYDROLOGY...
ISSUED AT 1255 PM EDT SUN APR 24 2016

MOST OF THE RAINFALL OVER THE NEXT COUPLE OF DAYS IS EXPECTED MONDAY
AFTERNOON THROUGH MONDAY NIGHT. HEAVIER SHOWERS AND SOME STRONG
STORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...
ESPECIALLY MONDAY EVENING AND MONDAY NIGHT. MOST BASINS WILL SEE
OVER A HALF INCH OF RAIN... WHILE STRONG THUNDERSTORMS AND TRAINING
OVER THE SAME AREAS COULD PRODUCE OVER AN INCH LOCALLY. EXPECT
PONDING OF WATER/LOCALIZED MINOR FLOODING IN POOR DRAINAGE AREAS IF
THIS OCCURS.

RIVER RISES ARE LIKELY... AND SOME RIVERS MAY RISE ABOVE BANKFULL
THIS WEEK. THE MAIN IMPACT WILL BE NUISANCE FLOODING NEAR RIVER
BANKS.

&&

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

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...04
HYDROLOGY...EBW
MARINE...JK



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