Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 211725
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
125 PM 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.

&&

.UPDATE...
ISSUED AT 1106 AM EDT SUN SEP 21 2014

WE HAVE UPDATED THE FCST THIS MORNING TO BUMP UP RAIN CHCS TO
CATEGORICAL FOR MANY LOCATIONS ACROSS THE CENTRAL AND NRN SECTIONS
OF THE CWFA THIS MORNING. THE UPPER LOW IS CURRENTLY MOVING ACROSS
THE REGION. THERE IS A BATCH OF RAIN EXTENDING FROM MUSKEGON TO
MT. PLEASANT THAT IS AHEAD OF THE CENTER OF THE LOW. THERE IS THEN
ANOTHER BATCH WRAPPING IN ON THE BACKSIDE OF THE LOW POISED TO
MOVE INTO THE NRN COUNTIES IN NEXT HOUR OR SO. THIS WILL ALL THEN
GRADUALLY SHIFT EAST THROUGH EARLY THIS EVENING.

A SMALL THUNDER THREAT STILL EXISTS ACROSS THE CENTRAL PORTION OF
THE CWFA NEAR THE CENTER OF THE UPPER LOW. CAN NOT RULE OUT SOME
SMALL HAIL OUT OF ANY ENHANCED SHOWER OR STORM WITH FREEZING
LEVELS AROUND 8K FEET OR SO.

&&

.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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 125 PM EDT SUN SEP 21 2014

NORTHWEST WIND GUSTS OF 25 TO 30 KNOTS AND AREAS OF MVFR IN RAIN
SHOWERS WILL CONTINUE THIS AFTERNOON. VFR CONDITIONS EXPECTED BY
LATE AFTERNOON AND EVENING AS THE RAIN ENDS AND WILL CONTINUE
OVERNIGHT AS WINDS ALSO DECREASE TO ABOUT 10 KNOTS BY 06Z.

&&

.MARINE...
ISSUED AT 1106 AM EDT SUN SEP 21 2014

WE HAVE UPGRADED THE ENTIRE NEARSHORE TO A GALE WARNING THROUGH
00Z THIS EVENING PER COLLABORATION WITH SURROUNDING OFFICES. STRONG COLD
AIR ADVECTION WITH THE UPPER LOW IS HELPING TO MIX DOWN 30 TO 35
KNOT WINDS ALONG THE LAKESHORE THIS MORNING WITH NW FLOW. WINDS
ARE EXPECTED TO PICK UP A TAD THROUGH EARLY AFTERNOON BEFORE
DIMINISHING THIS EVENING.

CAN NOT RULE OUT WATERSPOUTS THIS AFTERNOON WITH THE UPPER LOW
NEARBY...HOWEVER THE STRONG WINDS WILL LIKELY NEGATE THE THREAT
ENOUGH TO LEAVE A MENTION OUT OF THE FCST FOR NOW.


&&

.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 FROM 8 PM THIS EVENING TO 8 AM EDT MONDAY
     FOR LMZ844>849.

     GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.

&&

$$

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





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