Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 111140
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
740 AM EDT THU SEP 11 2014

LATEST UPDATE...
AVIATION/MARINE

.SYNOPSIS...
ISSUED AT 315 AM EDT THU SEP 11 2014

A TOUCH OF FALL WILL BE IN THE AIR THE NEXT FEW DAYS AS MUCH
COOLER AIR MOVES IN FROM CANADA. LAKE EFFECT CLOUDS AND ISOLATED
SHOWERS WILL BE AROUND TODAY. PATCHY FROST IS POSSIBLE NORTH OF
GRAND RAPIDS SATURDAY NIGHT.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 315 AM EDT THU SEP 11 2014

NO REAL IMPACTS EXPECTED ON THE SHORT TERM...WITH FORECAST ISSUES
BEING AMOUNT OF CLOUDS THROUGH THE PERIOD AND CHANCES OF RAIN FOR
LATE FRIDAY INTO EARLY SATURDAY.

FOR TODAY AND TONIGHT...CYCLONIC FLOW AND COLD ADVECTION SHOULD
KEEP STRATUS AROUND WITH OCCASIONAL SPRINKLES OR DRIZZLE ACROSS
THE NORTHWEST HALF OF THE FORECAST AREA WITH LAKE EFFECT MOISTURE
CONTRIBUTION. CLOUDS SHOULD LIMIT DIURNAL TEMPERATURE SWING WITH
HIGHS STRUGGLING TO REACH 60 TODAY AND FRIDAY AND LOWS GENERALLY
IN THE LOWER AND MID 40S. FROST THREAT IS THEREFORE MITIGATED
UNLESS CLOUDS ARE ABLE TO BREAK UP TONIGHT...WHICH IS NOT
EXPECTED GIVEN MOISTURE PROFILES...THE CURRENT EXTENT OF UPSTREAM
STRATUS AND EXPECTED LAKE EFFECT GENERATION.

SHARP SHORTWAVE TROUGH ARRIVES FRIDAY AND GENERATES ENOUGH LIFT TO
GO WITH LIKELY POPS FRIDAY NIGHT. BULK OF THE RAIN IS DEPARTING BY
SATURDAY MORNING...WITH SLOW CLEARING BY AFTERNOON.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 248 AM EDT THU SEP 11 2014

TWO ITEMS OF INTEREST REMAIN IN THE LONG TERM. THESE ITEMS ARE FROST
POTENTIAL ON SAT NIGHT...AND THEN THE ONLY REAL CHC OF RAIN IN THE
LONG TERM THAT WILL BE CENTERED AROUND THE MON/MON NIGHT TIME FRAME.

WE WILL SEE A FRESH COOL CANADIAN AIR MASS MOVE IN FOR THE BEGINNING
OF THE LONG TERM. THIS COOL AIR MASS WILL COME IN THE WAKE OF THE
STRONG WAVE EXPECTED TO MOVE THROUGH THE AREA DURING THE LATTER
PORTION OF THE SHORT TERM. FROST WILL BE POSSIBLE AT LEAST UP NORTH
IN THE NORMALLY COLDER LOCATIONS AS HIGH PRESSURE SETTLES OVERHEAD
FOR THE SAT NIGHT PERIOD AND WE SEE A NEARLY IDEAL RADIATIONAL
COOLING EVENT. THIS RIDGE WILL REMAIN IN CONTROL INTO SUN NIGHT
ALLOWING FOR COOL TEMPS AND DRY CONDITIONS.

WE WILL SEE OUR ONLY CHC OF RAIN IN THE LONG TERM COME MAINLY FOR
MON AND MON NIGHT FOR THE AREA. SOME SHORT WAVES WILL RIDE SE AND
CLIP THE AREA ON THE SRN PERIPHERY OF THE LONG WAVE TROUGH THAT WILL
BE ESTABLISHED ACROSS CENTRAL AND ERN CANADA. THIS WAVE HAS THE
POTENTIAL TO DIG DEEP ENOUGH TO TAP SOME GULF MOISTURE AND BRING IT
NORTH TOWARD THE AREA.

CONDITIONS WILL DRY OUT AND COOL DOWN SLIGHTLY THEN FOR THE END OF
THE LONG TERM ON TUE AND WED NEXT WEEK. THE TROUGH MOVING THROUGH ON
MON/MON NIGHT WILL SHIFT EAST OF THE AREA BY TUE. WE WILL SEE
SYNOPTIC SCALE RIDGING BUILD ACROSS THE ROCKIES AND WE WILL BE
DOWNSTREAM OF THAT RIDGE. MAX TEMPS WILL REMAIN IN THE 60S WITH H850
TEMPS EXPECTED TO HOLD IN THE SINGLE DIGITS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 740 AM EDT THU SEP 11 2014

MVFR CEILINGS EXPECTED TODAY WITH SOME ISOLATED SHOWERS. LOW
STRATUS HANGING AROUND. SOME IFR IS ALSO POSSIBLE. WINDS WILL BE
NORTHWEST AROUND 20 KNOTS FOR MUCH OF THE DAY.

&&

.MARINE...
ISSUED AT 740 AM EDT THU SEP 11 2014

THE GALE WARNING EXPIRED AT 5 AM AND THE SMALL CRAFT ADVISORY
CONTINUES THROUGH FRIDAY AFTERNOON. WINDS WILL CONTINUE TO
DIMINISH BUT GUSTS TO 25 KNOTS ARE POSSIBLE THIS MORNING.

&&

.HYDROLOGY...
ISSUED AT 315 AM EDT THU SEP 11 2014

SOME RISES EXPECTED ON RIVERS AS WIDESPREAD RAIN OF ONE HALF TO
ONE INCH FELL ACROSS LOWER MICHIGAN ON WEDNESDAY WITH THE HIGHEST
AMOUNTS ACROSS THE SOUTH...IN THE SAINT JOSEPH AND KALAMAZOO RIVER
BASINS.

&&

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

&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...OSTUNO
HYDROLOGY...OSTUNO
MARINE...OSTUNO





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