Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 282355
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
755 PM EDT FRI AUG 28 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 325 PM EDT FRI AUG 28 2015

PERIODS OF RAIN AND A FEW THUNDERSTORMS WILL MOVE INTO SOUTHWEST
MICHIGAN TONIGHT AND WILL CONTINUE INTO SATURDAY...BEFORE
DIMINISHING SATURDAY EVENING.  MUCH OF SUNDAY WILL BE DRY...BUT A
FEW SHOWERS WILL BE POSSIBLE OVER SOUTH CENTRAL LOWER.  TEMPERATURES
WILL REMAIN MILD WITH HIGHS MAINLY IN THE 70S.

NEXT WEEK APPEARS TO BE WARMER WITH HIGHS IN THE LOW TO MID 80S EACH
DAY.  RAIN CHANCES SHOULD REMAIN LOW.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 325 PM EDT FRI AUG 28 2015

A LARGE AREA RAIN COVERED MUCH OF WISCONSIN INTO IOWA THIS
AFTERNOON.  THIS WILL ARRIVE INTO SW MI LATER TONIGHT AND PERSIST
INTO SATURDAY.  OVERALL THE SYSTEM LOOKS WEAKER NOW...WITH LESS JET
DYNAMICS...SO RAINFALL TOTALS SHOULD NOT BE EXCESSIVE.

A SOMEWHAT DIFFUSED FRONTAL SYSTEM WILL AFFECT THE REGION LATER
TONIGHT THROUGH SATURDAY.  A LOW LEVEL JET IS NOW PROGGED TO NOSE
INTO NORTHERN LOWER TOWARD DAYBREAK SATURDAY...AND IT/S ENHANCEMENT
TO THE RAINFALL SHOULD REMAIN NORTH OF THE CWA.  HOWEVER THE RIGHT
ENTRANCE REGION OF THE UPPER JET MOVES OVER SW MI THIS EVENING AND
DOES NOT EXIT UNTIL SATURDAY EVENING.  SO THE UPPER FORCING SHOULD
MAINTAIN THE PCPN PATTERN INTO AND THROUGH THE AREA TOWARD MIDNIGHT
TONIGHT...THEN DIMINISH SATURDAY EVENING.  I INCREASED POPS ACROSS
THE NORTHERN CWA TONIGHT BASED ON RADAR TRENDS AND THE POSITION OF
THE UPPER JET.  THEN I ALSO INCREASED POPS OVER THE SOUTHERN CWA
SATURDAY NIGHT AS THE FRONT ONLY SLOWLY MOVES THROUGH.  OVERALL...
RAINFALL TOTALS SHOULD MAINLY BE 0.25 TO 0.50 INCHES.

THE FRONT GRADUALLY WASHES OUT NEAR THE MI/IN BORDER SUNDAY
MORNING/EARLY AFTERNOON AND THIS MAY KEEP A FEW WIDELY SCATTERED
SHOWERS OVER THE SE CWA.  ELSEWHERE SUNDAY SHOULD BE DRY.

TEMPS SHOULD REMAIN MILD...HOWEVER I DID LOWERED MAX TEMPS FOR
SATURDAY AS THE SHOWERS SHOULD BE FAIRLY PERSISTENT. HIGHS SHOULD BE
AROUND 70 IN MOST PLACES...75 TO 80 ON SUNDAY.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 325 PM EDT FRI AUG 28 2015

E CONTINUE TO EXPECT A CHANGE IN THE UPPER AIR PATTERN FOR THE LONG
TERM PORTION OF THE FCST BRINGING ABOVE AVERAGE TEMPERATURES TO THE
AREA. THERE WILL BE SOME SMALL CHCS OF SHOWERS/STORMS IN THE
FCST...BUT NOTHING MAJOR LOOKS TO BE EXPECTED AT THIS TIME.

WE WILL START OFF THE LONG TERM ON MON AND TUE WITH WARM AND MAINLY
DRY DAYS FOR THE STATE. UPPER RIDGING WILL BE BUILDING IN ACROSS THE
AREA AS A FAIRLY STRONG UPPER LOW WILL BE AFFECTING THE PACIFIC NW
AND THE CANADIAN WEST COAST. H850 TEMPS OF MID TEENS C WILL SUPPORT
HIGHS IN THE MID TO UPPER 80S. FAIRLY STRONG SUBSIDENCE AND WARM
TEMPS ALOFT SHOULD CAP ANY PCPN FROM OCCURRING.

WED THROUGH THU...AND POTENTIALLY INTO FRI WE WILL SEE TEMPS
STABILIZE A BIT AND SOME SMALL CHCS FOR CONVECTION DEVELOP. WE WILL
SEE A SHORT WAVE BE EJECTED FROM THE WRN TROUGH AND TRY TO KNOCK
DOWN THE RIDGE A BIT DURING THIS TIME. H850 TEMPS WILL HOLD OR
SLIGHTLY DROP WITH THE SLIGHT LOWERING OF UPPER HEIGHTS WITH THE
TROUGH. THE CHCS FOR RAIN DO NOT LOOK BIG RIGHT NOW AND WOULD BE
MORE OF A DIURNAL NATURE WITH A CAP ERODING A BIT.

ONCE THE TROUGH MOVES BY THE AREA...THE UPPER RIDGE LOOKS TO BUILD
ONCE AGAIN AS THE WRN TROUGH IS REINFORCED. THIS WILL ALLOW FOR
WARMING TEMPS ONCE AGAIN ALONG WITH A DECREASE IN PCPN CHCS. THIS
COULD TAKE PLACE AS EARLY AS FRI...OR OCCUR JUST AFTER THE LONG TERM
PERIOD ON SAT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 755 PM EDT FRI AUG 28 2015

RAIN WILL DEVELOP MAINLY AT KMKG LATE THIS EVENING AND OVERNIGHT
CAUSING CONDITIONS TO DETERIORATE TO MVFR VERY LATE TONIGHT AS
STEADIER RAIN MOVES IN. CONDITIONS SHOULD REMAIN VFR AT ALL THE REST
OF THE TERMINALS THIS EVENING AND OVERNIGHT WITH JUST A SMALL CHANCE
OF A SHOWER LATE TONIGHT.

RAIN SHOULD THEN DEVELOP FURTHER SE TO AFFECT ALL THE TERMINALS FROM
MID TO LATE SATURDAY MORNING THROUGH SATURDAY AFTERNOON. CONDITIONS
SHOULD STAY PRIMARILY VFR BUT SOME POCKETS OF MVFR ARE POSSIBLE IN
STEADIER SHOWERS. SHOWERS WILL LINGER INTO SATURDAY EVENING BEFORE
GRADUALLY ENDING.

&&

.MARINE...
ISSUED AT 325 PM EDT FRI AUG 28 2015

OTHER THEN THE CHANCE OF WIDELY SCATTERED THUNDERSTORMS LATE TONIGHT
THROUGH SATURDAY EVENING...THE LAKE SHOULD BE FAIRLY CALM.  WINDS
ARE EXPECTED TO REMAIN 15 KNOTS OR LESS THROUGH THE SHORT TERM.

&&

.HYDROLOGY...
ISSUED AT 325 PM EDT FRI AUG 28 2015

A QUARTER TO ONE HALF INCH OF RAIN IS EXPECTED TONIGHT INTO SUNDAY
MORNING.  THIS SHOULD NOT CAUSE HYDRO CONCERNS.

&&

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

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...NJJ
AVIATION...LAURENS
HYDROLOGY...JK
MARINE...JK



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