Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 161754
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
154 PM EDT SAT AUG 16 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 323 AM EDT SAT AUG 16 2014

SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY WITH THE
GREATEST LIKELIHOOD ACROSS CENTRAL LOWER MI THIS AFTERNOON WITH LESS
COVERAGE ANTICIPATED ACROSS SOUTHERN LOWER MI THIS EVENING AND
TONIGHT. MOST OF SUNDAY AND MONDAY WILL BE DRY ALTHOUGH A FEW
SHOWERS MAY POP UP BOTH DAYS MAINLY SOUTH OF A GRAND RAPIDS TO
LANSING LINE. TUESDAY THROUGH FRIDAY LOOKS WARM AND UNSETTLED AT
TIMES WITH OPPORTUNITIES FOR MORE SHOWERS AND STORMS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 1253 PM EDT SAT AUG 16 2014

CONVECTION THUS FAR HAS BEEN FAIRLY TAME AND NOT EXPECTING A BIG
UPTICK IN ACTIVITY EITHER. MOISTURE RETURN IN THE LOW LEVELS IS
NOT SIGNIFICANT IN TERMS OF 850MB MOISTURE TRANSPORT OR EVEN
SURFACE DEW POINTS. INSTABILITY IS THEREFORE EXPECTED TO BE
SOMEWHAT MARGINAL WITH CAPE VALUES AT 1000 J/KG OR LESS AND
SURFACE LI/S ON THE ORDER OF -2 TO -4 C. THE STRONGEST CELLS...NON
SEVERE...WILL LIKELY OCCUR BETWEEN NOW AND THE MID TO LATE AFTERNOON
AS THERE IS A 850MB LLJ THAT IS PEELING AWAY TO THE EAST AT THIS
TIME. MID LEVEL WINDS ARE DECENT ON THE ORDER OF 40-50KTS...WHICH
PUSHES THE 0-6KM SHEAR UP INTO THE 30-40KT RANGE. SO...DECENT
SHEAR IN PLACE...BUT INSTABILITY WILL BE LACKING. ENVISION A
BROKEN AREA OF SHOWERS AND STORMS GRADUALLY MIGRATING SOUTH
THROUGH THE FORECAST AREA THROUGH THE REMAINDER OF THE AFTERNOON
AND EVENING HOURS.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014

HIGH CONFIDENCE IN WARM SUMMERLIKE TEMPERATURES IN THE LONG TERM
PERIOD... ALTHOUGH IT LOOKS LIKE THE HOT/HUMID/UNCOMFORTABLE AIR
WITH HIGHS AROUND 90 AND DEW POINTS NEAR 70 SHOULD REMAIN JUST TO
OUR SOUTHWEST.

EARLY NEXT WEEK WE WILL BE WATCHING A SLOW MOVING SHORTWAVE WHICH
MOVES FROM NORTHERN MINNESOTA ON MONDAY TO WISCONSIN ON TUESDAY TO
LWR MI ON WEDNESDAY. A WEAK/ILL DEFINED SFC TROUGH/WARM FRONT...
ORIENTED IN A NW-SE FASHION... ACCOMPANIES/PRECEDES THIS FEATURE AS
IT IMPACTS THE UPR MIDWEST AND GRTLKS REGION DURING THE EARLY TO MID
WEEK PERIOD.

OUR BEST CHANCE OF SHOWERS/TSTMS WOULD APPEAR TO BE ON TUESDAY AND
WEDNESDAY... PARTICULARLY IN THE AFTERNOON/EVENING HOURS WITH
DIURNAL BOOST.

ONCE THE SHORTWAVE EXITS THE REGION BY THURSDAY... HEIGHT RISES
COMMENCE. HOWEVER A CHANCE OF A FEW SHOWERS AND TSTMS WILL REMAIN
SINCE THE WARM FRONT SHOULD BE SITUATED JUST TO OUR SOUTHWEST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 150 PM EDT SAT AUG 16 2014

MOSTLY VFR CIGS EXPECTED THROUGH 04Z OR SO. THE EXCEPTION IS AT
KGRR WHERE A MVFR CIG EXISTS. A WEAK COLD FRONT IS SAGGING SOUTH
THROUGH CENTRAL LOWER MICHIGAN. THE AREA OF SHOWERS WITH THE FRONT
HAS BEEN DECREASING IN COVEAGE DURING THE PAST FEW HOURS. KEPT A
VCSH COMMENT IN FOR THIS. OTHERWISE...IFR VIS POSSIBLE OVERNIGHT
IF SKIES CAN CLEAR OUT...WHICH SEEMS TO BE HAPPENING UPSTREAM.

&&

.MARINE...
ISSUED AT 1253 PM EDT SAT AUG 16 2014

UPDATED EARLIER FOR SOME MARINE FOG THAT CONTINUES TO BE LOCALLY
DENSE IN AND AROUND MUSKEGON. OTHER WEBCAMS ARE NOT SHOWING
ANYTHING CLOSE TO WHAT IS GOING ON AT MUSKEGON. SOME OF THE
COLDEST WATER IN THE NEARSHORE ZONE IS IN PLACE NEAR MUSKEGON
WHICH REPORTED A MORNING WATER TEMP OF 52 DEGREES. THE COLD WATER
FROM RECENT WAVE EVENTS COMBINED WITH OVERRIDING AIR THAT CONTAINS
DEW POINTS IN THE 60S IS RESULTING IN LOCALLY DENSE FOG. WILL SEE
HOW THE AFTERNOON PANS OUT...BUT WILL HOLD OFF ON A MARINE DENSE
FOG ADVISORY GIVEN THE SOMEWHAT LOCAL NATURE OF IT. HAVE FOG
MENTIONED IN THE HWO...SRF AND NSH.


&&

.HYDROLOGY...
ISSUED AT 323 AM EDT SAT AUG 16 2014

NO SIGNIFICANT RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS.

&&

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

$$

SYNOPSIS...HOVING
SHORT TERM...DUKE
LONG TERM...MEADE
AVIATION...93
HYDROLOGY...HOVING
MARINE...HOVING






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