000
FXUS63 KGRR 010352
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1149 PM EDT FRI OCT 31 2008

LATEST UPDATE...AVIATION

.SYNOPSIS...(350 PM EDT FRI OCT 31 2008)
A COLD FRONT WILL MOVE THROUGH LOWER MICHIGAN THIS TONIGHT. THE
FRONT WILL NOT PRODUCE ANY PRECIPITATION AS IT MOVES THROUGH. FAIR
WEATHER IS EXPECTED OVER THE WEEKEND EXCEPT FOR A SLIGHT CHANCE OF
SHOWERS LATE SUNDAY.

&&

.SHORT TERM...(350 PM EDT FRI OCT 31 2008)
(TONIGHT THROUGH SUNDAY NIGHT)
NO REAL WEATHER ISSUES IN THE NEAR TERM. COLD FRONT EXPECTED TO COME
THROUGH DRY TONIGHT...ALTHOUGH THE GFS IS STILL PAINTING SOME VERY
LIGHT QPF ACROSS OUR FAR SOUTHERN FORECAST AREA OVERNIGHT. BELIEVE
THAT MOISTURE IS TOO LIMITED TO ADD POPS TO THE FORECAST TONIGHT
ACROSS THE SOUTH. THEN FAIR WEATHER FOR SATURDAY AND SATURDAY NIGHT
AS SFC HIGH BUILDS IN.

SOME SHOWERS ARE POSSIBLE LATE SUNDAY AFTERNOON AND SUNDAY NIGHT AS
AREA OF ISENTROPIC ASCENT DEVELOPS IN GENERAL WARM AIR ADVECTION
PATTERN AS THE SFC HIGH MOVES OFF TO THE EAST...BUT ONCE AGAIN
MOISTURE IS LIMITED AND BEST ASCENT IS TO THE NORTH OF LOWER
MICHIGAN. WILL CARRY SLIGHT CHANCE POPS SUNDAY NIGHT ACROSS ALL BUT
THE FAR SOUTHERN FORECAST AREA.

&&

.LONG TERM...(350 PM EDT FRI OCT 31 2008)
(MONDAY THROUGH FRIDAY)
THE MAIN CHALLENGE IN THE LONG TERM PERIOD DEALS WITH THE TIMING AND
STRENGTH OF PRECIPITATION. THE MODELS SHOW A LOW PRESSURE SYSTEM
PASSING ACROSS CENTRAL CANADA AND DRAGGING A COLD FRONT THROUGH THE
AREA MONDAY. THE MOISTURE IS LACKING WITH THE FRONT AND THE MAJORITY
OF THE FORCING REMAINS FAR TO THE NORTH. HAVE NO PRECIPITATION IN
THE GRIDS FOR THIS FEATURE. MODELS SHOW WARMER AIR STREAMING INTO
THE GREAT LAKES REGION LATE MONDAY THROUGH WEDNESDAY. SHOULD HAVE
TEMPERATURES WELL ABOVE NORMAL. A STRONGER SYSTEM IS FORECAST TO
FORM IN THE LEE OF THE ROCKY MOUNTAINS AND MOVE INTO THE REGION BY
THURSDAY. THERE ARE LARGE DISCREPANCIES BETWEEN THE MID RANGE
MODELS... AND HAVE BROAD BRUSHED PRECIPITATION WEDNESDAY NIGHT
THROUGH FRIDAY DUE TO THE UNCERTAINTY IN TIMING AND TRACK OF THE
SYSTEM.

&&

.MARINE...(350 PM EDT FRI OCT 31 2008)
EXPECT NORTHEAST WINDS BEHIND THE FRONT TONIGHT WITH WAVES OF 2 TO 4
FEET. THINGS LOOK CALM OVER THE WEEKEND BUT WINDS WILL GO SOUTH AND
WAVES WILL BEGIN INCREASING BY MONDAY AS HIGH PRESSURE MOVES OFF TO
THE EAST.

&&

.AVIATION...(1149 PM EDT FRI OCT 31 2008)
THERE WILL BE SOME LIGHT FOG AND HAZE POSSIBLE IN THE FIRST FEW
HOURS OF THE 06Z TAF ISSUANCE. ADDED A TEMPO GROUP FOR SOME LIGHT
FOG TO COVER THIS THREAT. THE FOG IS OCCURRING IN THE SLACK GRADIENT
NEAR AND JUST BEHIND THE COLD FRONT THAT IS SLIDING SOUTH. ONCE THE
NORTHERLY WINDS PICK UP JUST A BIT THE FOG DISSIPATES. THINKING LATE
TONIGHT SHOULD SEE VFR VSBY/S AS NORTHERLY WINDS INCREASE IN THE
LOWEST 1500 FT. VERY LITTLE IN THE WAY OF CLOUDS ARE EXPECTED
TONIGHT/SATURDAY WITH VFR CONDITIONS EXPECTED ON SATURDAY AFTER THE
LIGHT MVFR FOG IN SPOTS TONIGHT.

&&

.HYDROLOGY...(350 PM EDT FRI OCT 31 2008)
NO HYDRO CONCERNS DUE TO DRY WX REGIME.

&&

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

&&

$$

SYNOPSIS:     OSTUNO
SHORT TERM:   OSTUNO
LONG TERM:    IOD
MARINE:       OSTUNO
AVIATION:     DUKE
HYDROLOGY:    OSTUNO