Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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964
FXUS63 KGRR 070010
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
810 PM EDT FRI MAY 6 2016

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 326 PM EDT FRI MAY 6 2016

A COLD FRONT NEAR LAKE SUPERIOR WILL MOVE ACROSS LOWER MICHIGAN LATE
TONIGHT AND SATURDAY MORNING. SHOWERS AND THUNDERSTORMS WILL DEVELOP
ACROSS LOWER MICHIGAN AS THE FRONT MOVES THROUGH. THE REST OF THE
WEEKEND WILL BE DRY.

TEMPERATURES WILL TOP OUT NEAR NORMAL SATURDAY IN THE 60S AND
SUNDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 326 PM EDT FRI MAY 6 2016

FORECAST CONCERNS DEAL WITH PCPN TRENDS TONIGHT AND SATURDAY
MORNING.

SFC ANALYSIS SHOWS A COLD FRONT APPROACHING FAR NW WISCONSIN AND
VERY LITTLE IN THE WAY OF PCPN ALONG IT. HOWEVER...TOWERING CU IS
BEGINNING TO DEVELOP AND WE/LL PROBABLY SEE THUNDERSTORMS DEVELOP
THIS EVENING. AS THE FRONT MOVES OVER LAKE MICHIGAN AROUND 06Z, IT
WILL ENCOUNTER QUITE A BIT OF ELEVATED INSTABILITY...LI/S NEAR -4C.
HOWEVER, MOISTURE IS LACKING. FORECAST SOUNDINGS DO SHOW AN INCREASE
IN LOW LEVEL MOISTURE LATE TONIGHT ACROSS CENTRAL AND SOUTHERN LOWER
MICHIGAN AS MOISTURE CONVERGENCE INCREASES AND THE LLJ STRENGTHENS A
BIT. STILL, SOUNDINGS DON/T SATURATE. SHOWERS APPEAR LIKELY AND
SCATTERED THUNDERSTORMS SHOULD DEVELOP AS THE FRONT MOVES ACROSS THE
CWA. THE HIGHEST INSTABILITY WILL BE FOUND SATURDAY MORNING ACROSS
THE SOUTHEAST CWA ROUGHLY SOUTHEAST OF A LANSING TO BATTLE CREEK
LINE. THE PCPN SHOULD MOVE OUT OF THE CWA BY 18Z OR SO.

HIGH PRESSURE BUILDS IN SATURDAY AFTERNOON AND WILL CONTINUE INTO
LATE SUNDAY. THIS WILL LEAD TO A SUNNY MOTHERS DAY WITH SEASONAL
HIGHS IN THE 60S.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 326 PM EDT FRI MAY 6 2016

NEXT WEEK FEATURES MULTIPLE OPPORTUNITIES FOR SHOWERS AND STORMS AS
A SERIES OF SHORTWAVE TROUGHS SWING THROUGH THE GREAT LAKES REGION.
HIGH TEMPERATURES WILL BE MILD IN THE 60S...WITH THE POTENTIAL FOR
70 DEGREES WEDNESDAY AND THURSDAY.

HIGHEST CONFIDENCE IN RAIN AND THUNDERSTORMS IS MONDAY NIGHT AND
TUESDAY. WILL INCLUDE CHANCE POPS ON MONDAY WITH MOISTURE
INCREASINGLY STEADILY DURING THE DAY... BUT THE DAY LOOKS MOSTLY DRY
GIVEN SHORTWAVE RIDGING AND EASTERLY LOW LEVEL FLOW. H850 SOUTHERLY
RETURN FLOW KICKS IN MONDAY NIGHT. ISENTROPIC ASCENT UP A WARM FRONT
WILL LIKELY RESULT IN WIDESPREAD SHOWER ACTIVITY WITH A CHANCE FOR
THUNDER MONDAY NIGHT.

THE NEGATIVELY TILTED OPEN WAVE SWINGS THROUGH TUESDAY INTO TUESDAY
NIGHT. A DECREASING CLOUD TREND FOLLOWS FOR WEDNESDAY INTO WEDNESDAY
NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION LATE
IN THE WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 810 PM EDT FRI MAY 6 2016

FOR THE MOST PART VFR WEATHER WILL PREVAIL TONIGHT AND SATURDAY
DUE TO THE DRY AIR MASS CURRENTLY IN PLACE. HOWEVER A 3-6 HOUR
PERIOD OF MVFR CIGS WITH SCATTERED RAIN SHOWERS IS POSSIBLE
SATURDAY MORNING WHILE A COLD FRONT IS PASSING THROUGH THE
REGION. WINDS WILL INCREASE OUT OF THE NORTH TO 15 TO 25 KNOTS BY
AFTERNOON BEHIND THE FRONT. SKIES WILL CLEAR BEHIND THE FRONT
TOO... BUT SOME SMOKE ALOFT RELATED TO THE CANADIAN FIRES MAY
ARRIVE AS WINDS ALOFT GO NORTHWESTERLY.

WHILE THUNDER CANNOT BE RULED OUT AT ANY OF THE TERMINALS LATE
TONIGHT AND SATURDAY MORNING... FEEL THE PROBABILITY IS TOO LOW
TO INCLUDE A MENTION IN THE TAFS. THE EXCEPTION IS AT JXN WHERE
SOME SFC INSTABILITY MAY DEVELOP MID TO LATE MORNING JUST BEFORE
THE FROPA.

&&

.MARINE...
ISSUED AT 338 PM EDT FRI MAY 6 2016

WINDS AND WAVES WILL NOT BE AN ISSUE TONIGHT. HOWEVER, A COLD FRONT
MOVING SOUTH TONIGHT MAY PRODUCE SOME THUNDERSTORMS AND GUSTY WINDS.
NORTH WINDS BEHIND THE FRONT WILL LIKELY CAUSE WINDS TO INCREASE TO
3 TO 5 FEET SATURDAY AND A SMALL CRAFT ADVISORY MAY BE NEEDED.


&&

.HYDROLOGY...
ISSUED AT 113 PM EDT FRI MAY 6 2016

RIVER FLOOD ADVISORIES ARE CURRENTLY POSTED FOR THE GRAND RIVER AT
IONIA... THE THORNAPPLE RIVER IN HASTINGS AND THE MAPLE RIVER IN
MAPLE RAPIDS. THE RIVER LEVELS AT THESE SITES ARE RISING OR HAVE
JUST PEAKED. THEY ARE JUST ABOVE BANKFULL LEVELS AND SHOULD CREST
TODAY OR SATURDAY BELOW FLOOD STAGE. RAINFALL THIS WEEKEND MAY SLOW
THE FALL OF RIVER LEVELS.

&&

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

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...EBW
AVIATION...MEADE
HYDROLOGY...63
MARINE...04



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