Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 180729
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
325 AM EDT MON AUG 18 2014

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE

.SYNOPSIS...
ISSUED AT 325 AM EDT MON AUG 18 2014

FAIR WEATHER WILL CONTINUE TODAY BEFORE A LOW PRESSURE SYSTEM
MOVING IN FROM THE NORTHERN PLAINS BRINGS SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TONIGHT THROUGH TUESDAY. A FEW SHOWERS AND
STORMS MAY LINGER INTO WEDNESDAY. TEMPERATURES WILL BE NEAR NORMAL
THE NEXT FEW DAYS WITH HIGH TEMPERATURES IN THE UPPER 70S TO NEAR
80 DEGREES.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 325 AM EDT MON AUG 18 2014

OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
PROBABILITIES FOR SHOWERS AND STORMS TONIGHT THROUGH WEDNESDAY.

A FAIRLY WEAK SURFACE AND UPPER LEVEL LOW PRESSURE SYSTEM WILL
MOVE IN FROM THE NORTHERN PLAINS TONIGHT THROUGH TUESDAY AND BRING
SCATTERED SHOWERS AND A FEW TSTORMS. OVERALL CONVECTIVE POTENTIAL
TONIGHT INTO TUESDAY LOOKS FAIRLY LOW THOUGH DUE TO RATHER WEAK
INSTABILITY AND A WEAK LLJ. MOISTURE TRANSPORT SHOULD BE SUFFICIENT
ENOUGH FOR A FEW STORMS THROUGH TUESDAY BUT NO SEVERE WEATHER IS
ANTICIPATED.

A FEW SHOWERS AND ISOLATED STORMS MAY LINGER TUESDAY NIGHT AND
WEDNESDAY WITH THE UPPER LEVEL LOW PRESSURE SYSTEM STILL OVER OUR
REGION. AS FOR TODAY... FAIR WX IS ANTICIPATED AFTER SOME PATCHY
EARLY MORNING FOG. MAX TEMPS WILL REACH THE UPPER 70S TO AROUND 80
DEGREES.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 325 AM EDT MON AUG 18 2014

PRIMARY FORECAST ISSUE IN THE EXTENDED IS TRYING TO PIN DOWN THOSE
PERIODS THAT POPS CAN BE DROPPED. SFC AND SHORTWAVE UPPER RIDGING
SHOULD BRING FAIR WEATHER WEDNESDAY NIGHT AND EARLY THURSDAY BUT
WARM ADVECTION BEGINS THURSDAY WITH SHOWERS AND THUNDERSTORMS
EXPECTED NORTH OF THE SLOW MOVING SFC WARM FRONT...WITH THE HIGHEST
CHANCES ACROSS THE SOUTHERN FORECAST AREA. AN AREA OF ISENTROPIC
ASCENT CONTINUES TO BRING SHOWERS AND THUNDERSTORMS THURSDAY NIGHT
AND FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM EDT SUN AUG 17 2014

THE VFR CONDITIONS ACROSS MOST OF SOUTHWEST MI WILL GIVE WAY TO
LOWER CONDITIONS TONIGHT AS THE ATMOSPHERE COOLS OFF AN IT REMAINS
RELATIVELY MOIST. I AM NOT AS CERTAIN THAT WIDESPREAD IFR WILL
OCCUR AND HAVE BACKED OFF ON THE DURATION AND COVERAGE OF THE
STRATUS/FOG LATER TONIGHT. AS OF NOW IT APPEARS THAT THE KAZO TO
KBTL AND INTO KJXN REGION STANDS THE HIGHEST CHANCE FOR LOWER
CONDITIONS. A RETURN TO VFR IS EXPECTED DURING THE LATE MORNING TO
EARLY AFTERNOON OURS AS TEMPERATURES CLIMB.

WE ARE MONITORING A FEW SHOWERS ACROSS SOUTHERN LOWER MI. THEY
COULD ADD ADDITIONAL MOISTURE TO THE LOW LEVELS AND INCREASE THE
RISK FOR IFR AND LOWER CONDITIONS. I DID ADD VCSH TO THIS REGION
FOR TONIGHT.

MOISTURE STARTS TO INCREASE MON EVENING FROM THE WEST. THUS I
ADDED MVFR AND VCSH TO THE FORECAST FOR KMKG


&&

.MARINE...
ISSUED AT 325 AM EDT MON AUG 18 2014

WEAK OFFSHORE EASTERLY FLOW WILL RESULT IN WAVE HEIGHTS OF ONLY A
FOOT OR LESS TODAY. FAIRLY MINIMAL WIND AND WAVE ACTION IS
ANTICIPATED TONIGHT THROUGH MIDWEEK.

&&

.HYDROLOGY...
ISSUED AT 154 PM EDT SUN AUG 17 2014

ONE TO OVER 2 INCHES OF RAIN FELL OVER PARTS OF THE MACATAWA AND
KALAMAZOO RIVER BASINS OVER THE LAST 24 HOURS. QUICK RISES ARE
POSSIBLE IN THESE BASINS... THOUGH NO FLOODING IS EXPECTED. LITTLE
RAINFALL IS EXPECTED THROUGH MONDAY... WHICH WILL ALLOW RIVER LEVELS
TO RECEDE.

ELSEWHERE... RIVERS ARE RUNNING A LITTLE ABOVE NORMAL BUT ARE STILL
FAR BELOW BANK FULL. MOSTLY LIGHT PRECIPITATION IS POSSIBLE MONDAY
NIGHT THROUGH THURSDAY... WITH TOTALS EXPECTED TO END UP MOSTLY
AROUND AN INCH. THIS SHOULD LEAD TO SLOW RISES ON THE AREAS RIVER
SYSTEMS WITH PEAK LEVELS BELOW FLOOD STAGE OCCURRING BY THE END OF
THE WEEK.

&&

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

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...MJS
HYDROLOGY...63
MARINE...LAURENS







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