Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 271510
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1110 AM EDT SAT JUN 27 2015

LATEST UPDATE...
HYDRO

.SYNOPSIS...
ISSUED AT 328 AM EDT SAT JUN 27 2015

AN UNSEASONABLY STRONG STORM SYSTEM FOR THIS TIME OF YEAR WILL
TRACK ACROSS THE SOUTHERN GREAT LAKES TODAY...HEADING INTO CENTRAL
NEW YORK STATE BY SUNDAY MORNING. THIS WILL BRING STRONG
WINDS...LOCALLY HEAVY RAIN AND UNSEASONABLY CHILLY TEMPERATURES TO
INTERSTATE 69 AREA TODAY. AREAS NORTH AND WEST OF A LINE FROM
HOLLAND TO ALMA WILL HAVE PARTLY CLOUDY SKIES AND HIGHS IN THE
70S. BY TONIGHT THE STORM WILL BE FAR ENOUGH AWAY FROM THIS AREA
SO THAT SKIES SHOULD CLEAR FROM WEST TO EAST. SUNDAY SHOULD BE
PARTLY SUNNY. ANOTHER STORM SYSTEM WILL BRING SHOWERS AND
SCATTERED THUNDERSTORMS INTO THE AREA MONDAY. THOSE MAY LINGER
INTO TUESDAY. BEHIND THAT SYSTEM CANADIAN HIGH PRESSURE BUILDS
INTO THE AREA FOR MID WEEK. THAT WILL MEAN COOL TEMPERATURES FOR
THIS TIME OF YEAR BUT MOSTLY CLEAR SKIES.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EDT SAT JUN 27 2015

A RATHER UNUSUAL STORM FOR THIS TIME OF YEAR WILL TRACK THROUGH
THE SOUTHERN GREAT LAKES TODAY AND OVER WESTERN LAKE ERIE TONIGHT.
IT WILL BRING STRONG WINDS...CLOSE TO ADVISORY CRITERIA IN THE
INTERSTATE 69 AREA WITH RAIN...HEAVY AT TIMES. BUT AREAS NORTH AND
WEST OF A LINE FROM HOLLAND TO ALMA WILL HARDLY KNOW THE STORM IS
IN OUR AREA AS SKIES WILL BE PARTLY CLOUDY AND WINDS WILL NOT BE
ALL THAT STRONG EITHER. THE GLITCH FOR THIS FORECAST IT TO DECIDE
JUST HOW FAR WEST AND NORTH THE RAIN ACTUALLY GETS TODAY.

THE GEFS CLIMATE ANOMALIES FOR THIS SYSTEM TELL THE STORY. THE
SURFACE PRESSURE OF THE LOW FALLS TO BELOW 1000 MB...THAT IS
NEARLY 3.5 STANDARD DEVIATIONS FROM NORMAL OR HAS A RETURN
INTERVAL AT THIS TIME OF YEAR OF AROUND ONCE IN TEN YEARS. THIS
IS ONE OF THOSE COUPLED JET EVENTS WITH STRONG DYNAMICS AND A LOT
OF GULF MOISTURE TO WORK WITH. THE DEFORMATION ZONE OF THE SYSTEM
SETS UP OVER OUR SE CWA TODAY BUT THERE IS A CONSIDERABLE AMOUNT
OF LOW LEVEL DRY AIR FEEDING INTO THE SYSTEM FROM THE NORTH
(BLOCKING HIGH OVER SOUTHERN CANADA). THE MODELS HAVE BE VERY
INCONSISTENT WITH JUST HOW FAR WEST THE RAIN GETS. FOR NOW I AM
GOING WITH A BLEND OF THE RAP MODEL AND HRRR AND CALLING THAT
GOOD.

WINDS WILL BE AN ISSUE WITH THIS STORM TOO...THE RAP MODEL IS
SHOWING 45 TO 50 KNOTS OVER JACKSON FROM 8 AM THROUGH SUNSET JUST
ABOVE THE SURFACE. THE MIXING HEIGHT TAPS INTO THIS SO I WOULD
EXPECT SOME GUSTS TO BETWEEN 40 TO 45 KNOTS THIS AFTERNOON IN THAT
AREA... JUST UNDER ADVISORY CRITERIA. THIS WILL HAVE TO BE
WATCHED.

ALL OF THIS MOVES OUT THIS EVENING. THE NEXT SYSTEM MOVES IN
SUNDAY NIGHT INTO MONDAY. SINCE THE POLAR JET IS WELL SOUTH OF US
BY THEN...THIS WILL BE MORE OF A SHOWERY DAY WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EDT SAT JUN 27 2015

WE CONTINUE TO EXPECT THAT WE WILL BE UNDER THE INFLUENCE OF AN
UNSETTLED WEATHER PATTERN FOR THE FIRST FEW PERIODS OF THE LONG TERM
PORTION OF THE FCST. THE ANTICIPATED LONG WAVE TROUGH WILL BE OVER
THE AREA FROM MON NIGHT INTO TUE NIGHT. THE BEST CHC OF RAIN WILL
BEST MON NIGHT WITH A FAIRLY STOUT CLOSED SHORT WAVE AND ASSOCIATED
SFC LOW PASSING THROUGH. RAIN WILL REMAIN POSSIBLE TUE AND TUE
NIGHT...BUT IT DOES NOT LOOK TO BE AS WIDESPREAD WITH A WEAKER WAVE
MOVING THROUGH. IT WILL ALSO BE MORE DIURNALLY FOCUSED AND AWAY FROM
THE LAKE.

THE TREND OVER THE PAST COUPLE OF DAYS HAS DEFINITELY BEEN FOR A
DRIER PERIOD FOR THE MID PORTION OF THE WEEK FROM WED THROUGH THU.
THIS OCCURS AS THE LONG WAVE TROUGH IS PUSHED EAST OF THE AREA AND
WE BECOME UNDER THE INFLUENCE OF SUBSIDENCE DOWNSTREAM OF THE LONG
WAVE RIDGE ACROSS THE WRN HALF OF THE CONUS. WE WILL LIKELY REMAIN A
LITTLE COOLER THAN AVERAGE WITH THE NW FLOW ALOFT.

THE BREAK IN THE RAIN AND QUIET WEATHER LOOKS TO BE SHORT LIVED AS
THE NEXT CHC OF PCPN WILL START MAKING ITS WAY TOWARD THE AREA ON
FRI. THIS OCCURS AS THE NEXT STRONGER SHORT WAVE RIDING DOWN THE WRN
RIDGE WILL APPROACH FROM THE NW. THIS WILL LIKELY NOT HAVE RICH
MOISTURE TO WORK WITH AS GULF MOISTURE REMAINS LOCKED UP DOWN SOUTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 741 AM EDT SAT JUN 27 2015

RAIN WILL CONTINUE FOR MOST OF THE DAY OVER TAF SITES NEAR I-69.
EXPECT CIGS/VSBY TO BECOME IFR BY 16Z AT ALL OF THOSE TAF SITES.
IT WILL BECOME VERY WINDY TOO WITH NORTHEAST WINDS OF 15 TO 25
KNOTS WITH GUSTS TO NEAR 35 KNOTS. RAIN WILL END FROM WEST TO EAST
DURING THE LATE AFTERNOON AND EARLY EVENING. LOW CLOUDS MAY
PERSIST FOR LAN AND JXN THROUGH THE NIGHT.

MEANWHILE FOR MKG... SOLID VFR AND NOT NEARLY AS WINDY. SKIES
SHOULD BE MOSTLY CLEAR MOST OF THE DAY THERE ONCE THE CIRRUS
SHIELD MOVES OUT BY MID MORNING. GRR WILL BE ON THE EDGE OF RAIN
SHIELD TILL AROUND 16Z THEN EXPECT SLOWLY CLEARING SKIES THERE
TOO. WINDS WILL BECOME LIGHT AFTER SUNSET FOR BOTH MKG AND GRR.

&&

.MARINE...
ISSUED AT 328 AM EDT SAT JUN 27 2015

THE GOOD NEWS IS THE STORM IS JUST FAR ENOUGH TO THE SOUTH AND
EAST THAT IT WILL HAVE LITTLE IMPACT ON THE NEAR SHORE WATERS. SO
NO HEADLINES SEEM NEEDED AT THIS POINT.

&&

.HYDROLOGY...
ISSUED AT 1110 AM EDT SAT JUN 27 2015

RIVER FLOOD ADVISORIES REMAIN IN EFFECT AS RUNOFF OF RAINFALL MAKES
ITS WAY THROUGH THE RIVER SYSTEM. RAIN ACCUMULATIONS THROUGH THE
NEXT WEEK ARE EXPECTED TO BE A HALF INCH IN MOST AREAS WITH UP TO
AN INCH AND A HALF IN THE SOUTH. SIGNIFICANT FLOODING IS NOT
EXPECTED... BUT MINOR FLOODING ALONG RIVERS AND IN LOW-LYING AREAS
MAY PERSIST THROUGH THE WEEK.

&&

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

&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...WDM
HYDROLOGY...63
MARINE...WDM



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