Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 211143
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
743 AM EDT SUN SEP 21 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 AM EDT SUN SEP 21 2014

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL BRING CLOUDS AND SHOWERS
AND ISOLATED THUNDERSTORMS TODAY. THE SYSTEM WILL MOVE OUT TONIGHT
AND ALLOW SKIES TO GRADUALLY CLEAR. HIGH PRESSURE WILL BRING FAIR
WEATHER THROUGH THE UPCOMING WEEK. IT WILL BE SEASONABLY COOL
MONDAY. TEMPERATURES WILL MODERATE TO ABOVE NORMAL FOR MID TO
LATE WEEK.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 300 AM EDT SUN SEP 21 2014

SHOWERS AND SCATTERED CONVECTION WILL CONTINUE TO MOVE ACROSS OUR
AREA EARLY THIS MORNING IN THE FORM OF A NON SEVERE AND WEAKENING
QLCS. NO SEVERE WX REPORTS WERE NOTED WITH THIS ACTIVITY AS IT MOVED
ACROSS WI EARLIER TONIGHT. INSTABILITY OVER OUR AREA IS WEAK BUT
STRONG SPEED SHEAR IS NOTED. THEREFORE ISOLATED MINI BOWS MAY RESULT
IN GUSTS TO AROUND 35 TO 40 KTS FOR THE NEXT FEW HOURS BUT NO SEVERE
WX IS ANTICIPATED. KGRR RADAR TRENDS THE PAST HOUR OR SO ALREADY
INDICATE WEAKENING. BIG SABLE POINT REPORTED A PEAK GUST OF 41 MPH
AS THE STORMS CAME ONSHORE AFTER JUST AFTER 06Z EARLY THIS MORNING.

SHOWERS WILL REDEVELOP LATER TODAY AS THE UPPER TROUGH AXIS MOVES
OVERHEAD BY 18Z. AN ISOLATED STORM OR TWO IS ALSO POSSIBLE LATER
TODAY DUE TO INSTABILITY FROM DAYTIME HEATING AND AS THE POOL OF
COLDER AIR ALOFT MOVES IN. IT WILL BECOME BREEZY LATE THIS MORNING
AND AFTERNOON AS WINDS VEER TO THE NW AND INCREASE TO 15 TO 25 MPH
WITH GUSTS TO 30 MPH... HIGHEST RIGHT ALONG THE LAKE MI SHORELINE.

FAIR WX IS ANTICIPATED THROUGH THE REST OF THE SHORT TERM FCST
PERIOD AS HIGH PRESSURE BUILDS IN. SKIES WILL GRADUALLY CLEAR
TONIGHT AS THE H5 TROF AXIS SHIFTS EAST AND LOW LEVEL WINDS BECOME
MORE NORTHERLY AND ADVECT DRIER AIR IN. SEASONABLY COOL CONDITIONS
ARE ANTICIPATED MONDAY WITH MAX TEMPS REACHING THE UPPER 50S TO
LOWER 60S. IT WILL BE AT LEAST TEN DEGREES MILDER TUESDAY WHEN MAX
TEMPS WILL REACH THE UPPER 60S TO LOWER 70S WITH MOSTLY CLEAR SKIES.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM EDT SUN SEP 21 2014

A HIGH PRESSURE RIDGE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
LONG RANGE FORECAST PERIOD. MAX TEMPS DAILY WILL REACH THE 70S WITH
MIN TEMPS PRIMARILY IN THE 45 TO 55 DEGREE RANGE. THE MILDEST
TEMPERATURES ARE ANTICIPATED LATE IN THE WEEK AS THE UPPER LEVEL
RIDGE BECOMES MORE AMPLIFIED OVER THE GREAT LAKES REGION. MILD AND
DRY WX WILL LIKELY CONTINUE THROUGH THE WEEKEND INTO NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 742 AM EDT SUN SEP 21 2014

AS THE UPPER TROUGH MOVES THROUGH THE AREA EXPECT A PERIOD OF LOW
CEILING AND SHOWERS...THIS WILL LARGELY BE FROM 14Z TILL 18Z. ALSO
DURING THIS TIME THE MIXING HEIGHT INCREASES AND THAT SHOULD MIX
DOWN WIND GUSTS TO NEAR 30 KNOTS. BEHIND THE TROUGH EXPECT A
PERIOD OF VFR CIGS INTO THIS EVENING. OVERNIGHT WRAP AROUND LOW
CLOUDS MOVE BACK IN SO MVFR CIGS WILL ONCE AGAIN PREVAIL. WINDS
SPEEDS WILL BE AROUND 10 KNOTS OVERNIGHT.

&&

.MARINE...
ISSUED AT 300 AM EDT SUN SEP 21 2014

THE SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY THROUGH TONIGHT.
WINDS WILL VEER TO THE WEST TO NORTHWEST TODAY AND STRENGTHEN
TO 20 TO 30 KTS CAUSING WAVE HEIGHTS TO BUILD TO AROUND 4 TO 8
FEET THIS AFTERNOON AND EVENING. WIND SPEEDS MAY BRIEFLY FLIRT
WITH GALE FORCE THIS AFTERNOON BUT WILL STICK WITH THE THINKING OF
THE PREVIOUS SHIFT AND CONTINUE TO COVER THIS WITH THE SMALL CRAFT
HEADLINE. WAVE HEIGHTS WILL SLOWLY SUBSIDE LATE TONIGHT AS WIND
SPEEDS DIMINISH.


&&

.HYDROLOGY...
ISSUED AT 300 AM EDT SUN SEP 21 2014

LOCALLY HEAVY RAINFALL OCCURRED YESTERDAY AFTERNOON AND OVERNIGHT.
SOME RISES IN AREA RIVER LEVELS WILL CONTINUE TO OCCUR BUT OTHER
THAN ISOLATED MINOR URBAN AND SMALL STREAM TYPE ISSUES EARLY THIS
MORNING... NO SIGNIFICANT HYDRO ISSUES ARE ANTICIPATED. IT IS
NOTED THAT THE GRAND RIVER AT JACKSON QUICKLY SPIKED UP TO ABOVE 12
FEET YESTERDAY EVENING BUT REMAINED BELOW ACTION STAGE AND THE RIVER
LEVEL THERE HAS ALREADY TRENDED BACK DOWNWARD SIGNIFICANTLY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.

&&

$$

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





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