Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 241928
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
328 PM EDT SUN AUG 24 2014

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

.SYNOPSIS...
ISSUED AT 328 PM EDT SUN AUG 24 2014

MONDAY AND TUESDAY WILL SEE WARMER AND MORE HUMID CONDITIONS WITH
SCATTERED THUNDERSTORMS. SOME HEAVIER RAIN IS POSSIBLE TUESDAY
NIGHT AS A COLD FRONT SINKS SOUTH THROUGH LOWER MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 328 PM EDT SUN AUG 24 2014

FORECAST IMPACTS IN THE NEAR TERM INCLUDE PATCHY FOG TONIGHT ALONG
WITH HEAT INDICES IN THE LOWER 90S MONDAY AND TUESDAY AFTERNOON.
SCATTERED THUNDERSTORMS ARE POSSIBLE AS LIFTED INDICES ARE AROUND
MINUS 6 BOTH DAYS...BUT COVERAGE WILL BE ISOLATED TO SCATTERED
BEFORE THE COLD FRONT ARRIVES LATER TUESDAY TO FOCUS CONVECTION.
SEVERE WEATHER RISK IS LIMITED AS SHEAR REMAINS RELATIVELY WEAK.
FLOODING POTENTIAL IS THERE HOWEVER. SEE HYDROLOGY SECTION FOR
DETAILS. LOOKS LIKE THE MOST FAVORABLE CONDITIONS FOR HEAVY RAIN
OCCUR TUESDAY NIGHT.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 328 PM EDT SUN AUG 24 2014

A COLD FRONT SHOULD BE NEAR THE MI/IN BORDER WEDNESDAY AS HIGH
PRESSURE BUILDS IN FROM WISCONSIN. WE PUSHED POPS A BIT FARTHER
SOUTH WEDNESDAY BUT THE EXACT POSITION OF THE FRONTAL BOUNDARY ISN/T
CERTAIN AT THIS POINT. IT/S LIKELY THOUGH THE THE BULK OF THE PCPN
ASSOCIATED WITH THE BOUNDARY WILL BE OVER NORTHERN INDIANA OR
PERHAPS FAR SOUTHERN LOWER MICHIGAN.

THE BOUNDARY BEGINS LIFTING NORTHWARD THURSDAY IN RESPONSE TO
DEVELOPING LOW PRESSURE IN THE PLAINS. WE/LL KEEP A SLIGHT CHANCE OF
PCPN IN THE GRIDS BUT MOST LOCATIONS WILL BE DRY.

THE BEST CHANCE OF RAIN LOOKS TO BE FRIDAY/SATURDAY WHEN THE LOW
MOVES ENE TOWARD LOWER MICHIGAN AND THE WARM FRONT MOVES NORTH
ACROSS THE CWA. HIGHS WILL BE IN THE MID TO UPPER 70S THROUGH THE
PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 137 PM EDT SUN AUG 24 2014

MORNING STRATOCU IS SCATTERING OUT AND ALL TAF SITES SHOULD BE VFR
BY MID AFTERNOON. EXPECT MVFR/IFR TO DEVELOP OVERNIGHT AS FOG
DEVELOPS AFTER MIDNIGHT.

&&

.MARINE...
ISSUED AT 328 PM EDT SUN AUG 24 2014

WINDS WILL VEER TO THE SOUTH ON MONDAY BUT WAVES WILL ONLY BUILD
TO AROUND 2 FEET AS FLOW WILL BE RELATIVELY LIGHT. VISIBILITY COULD
BE REDUCED AT TIMES IN FOG TONIGHT THROUGH TUESDAY. THUNDERSTORMS
ARE POSSIBLE MONDAY AND TUESDAY AFTERNOONS.

&&

.HYDROLOGY...
ISSUED AT 1104 AM EDT SUN AUG 24 2014

BEST CHANCE FOR SIGNIFICANT RAINFALL WOULD BE MONDAY NIGHT THROUGH
WEDNESDAY WITH A SLOW MOVING COLD FRONT. THIS IS NOT A GUARANTEE
AS THE LLJ IS FORECAST TO BE QUITE WEAK. NEVERTHELESS...A VERY
MOIST ATMOSPHERE COMBINED WITH FORCING VIA THE COLD FRONT AND SLOW
CELL MOVEMENT COULD RESULT IN SOME SIGNIFICANT RAINFALL IF STORMS
DEVELOP OVER OUR AREA. PW VALUES WILL LIKELY BE AROUND 1.75"
MONDAY NIGHT AND TUESDAY. MODEL GUIDANCE IS MIXED REGARDING HOW
LONG THE FRONT MAY HANG UP...SO IT IS UNCLEAR WHEN THE THREAT FOR
SIGNIFICANT RAINFALL WOULD END.

&&

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

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...93
HYDROLOGY...HOVING
MARINE...OSTUNO



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