Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 210827
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
326 AM EST FRI NOV 21 2014

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

.SYNOPSIS...
ISSUED AT 326 AM EST FRI NOV 21 2014

THE COLDER AIR THAT HAS PLAGUED THE AREA OVER THE LAST WEEK OR SO
WILL GRADUALLY BE SCOURED OUT DURING THE DAY ON SAT. WITH THE COLDER
AIR ON ITS WAY OUT...THE LAKE EFFECT WILL COME TO AN END FOR THE
AREA.

WE COULD SEE A MIXTURE OF SLEET AND FREEZING RAIN LATE TONIGHT AND
EARLY SATURDAY MORNING AS THIS WARMER AIR STARTS TO ARRIVE. ANY
MIXTURE OF PRECIPITATION WILL CHANGE OVER TO ALL RAIN BY SATURDAY
AFTERNOON EVERYWHERE. OCCASIONAL RAIN...DRIZZLE...AND FOG CAN BE
EXPECTED OVER THE COMING WEEKEND ALONG WITH TEMPERATURES WELL INTO
THE 40S AND APPROACHING 50.

COOLER AIR WILL MOVE BACK IN ACROSS THE AREA NEXT WEEK ALONG WITH
CHANCES OF SNOW SHOWERS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 326 AM EST FRI NOV 21 2014

WE ARE CANCELING THE REMAINDER OF THE WINTER WEATHER ADVISORY
ACROSS THE AREA WITH THE FCST PACKAGE THIS MORNING. OUR FOCUS FOR
THE SHORT TERM IS ON THE POTENTIAL OF A MIXED BAG OF PCPN FOR LATER
TONIGHT AND EARLY ON SAT.

LAKE EFFECT IS DYING A QUICK DEATH ACROSS THE AREA THIS MORNING.
THIS IS HAPPENING AS THE UPPER JET IS NOW SHIFTING EAST OF THE AREA
AND INVERSION HTS ARE CRASHING STEADILY. WE WILL HAVE SOME
FLURRIES/LOW CHCS FOR MEASURABLE PCPN THIS MORNING NEAR THE
LAKESHORE...BUT IT WILL NOT BE SIGNIFICANT. WE HAVE ALREADY SEEN
CLEARING TAKE PLACE ACROSS THE NE PORTION OF THE CWFA THIS MORNING.
IT IS TRYING TO MAKE PROGRESS TOWARD THE SOUTH AND WEST...BUT IS
GETTING HELD UP NOW. WE DO EXPECT THAT AFTER SOME EARLY
CLEARING...SOME LAKE EFFECT CLOUDS WILL MOVE INLAND AND DISPERSE
THIS AFTERNOON WITH THE FLOW BECOMING WEST AND THEN SOUTH.

WE ARE STILL ON SCHEDULE FOR SOME LIGHT MIXED PCPN TO OCCUR ACROSS
THE AREA LATE TONIGHT AND EARLY SAT MORNING. WE WILL SEE THE INITIAL
SURGE OF WARMER AND MORE MOIST AIR AHEAD OF THIS WEEKEND/S SYSTEM
MAKE ITS WAY TOWARD THE AREA TONIGHT. SUFFICIENT SATURATION WILL
TAKE PLACE DURING THE SECOND HALF OF THE NIGHT FOR PCPN TO BREAK
OUT. THE SNOW COVERED GROUND AND ARCTIC AIR IN PLACE AT THE SFC WILL
HOLD A BIT LONGER WHILE THE MUCH WARMER AIR ALOFT MOVES OVERHEAD.
THIS WILL CREATE A TEXTBOOK CASE FOR PRODUCING SOME SLEET AND
FREEZING RAIN ACROSS THE AREA.

WE COULD SEE A FEW HUNDREDTHS OF QPF/ICING...HOWEVER WE ARE NOT
EXPECTING SIGNIFICANT ICING ACROSS THE AREA. A HEADLINE MAY BE
NEEDED FOR A SHORT PERIOD. SRLY FLOW BRINGING IN THE WARMER AIR AND
LATENT HEAT FROM THE RAIN WILL DRIVE TEMPS UP ABOVE FREEZING ACROSS
THE ENTIRE AREA BY SAT AFTERNOON. RAIN WILL REMAIN RELATIVELY LIGHT
SAT AFTERNOON...AND LOOKS TO TRANSITION TO MORE DRIZZLE/FOG SAT
NIGHT AS BETTER MOISTURE TRANSPORT MOVES OUT...AND SHALLOW MOISTURE
REMAINS IN PLACE WITH THE CONTINUING WARM AND MOIST ADVECTION IN THE
LOW LEVELS.

WE WILL SEE THE CHC FOR RAIN INCREASE SIGNIFICANTLY THROUGH THE DAY
ON SUN. THE MAIN SUPPORTING WAVE WILL BEGIN TO APPROACH THE AREA
DURING THE SUN AFTERNOON PERIOD. WE WILL SEE A MUCH STRONGER PUSH OF
MOISTURE TRANSPORT WITH THIS WAVE...AND SO WE EXPECT A BETTER CHC OF
PCPN AT THAT TIME. INSTABILITY IS NOT PRESENT THROUGH SUN...SO WE
HAVE LEFT OUT THAT WORDING FOR THE TIME BEING.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 326 AM EST FRI NOV 21 2014

WIDESPREAD RAIN AND MILD TEMPERATURES SUNDAY NIGHT WILL BE FOLLOWED
BY FALLING TEMPERATURES AND SNOW SHOWERS BY LATE MONDAY AS A
DEEPENING LOW PRESSURE SYSTEM LIFTS NORTH THROUGH THE GREAT LAKES
REGION.

IMPACT WEATHER APPEARS LIKELY FOR LATE MONDAY NIGHT AND TUESDAY
FEATURING SLIPPERY ROADS AND REDUCED VISIBILITIES. TEMPERATURES FOR
THE MORNING COMMUTE TIME ARE EXPECTED TO BE BELOW FREEZING WITH LAKE
SNOWS IN PROGRESS. ANY STANDING WATER FROM THE PREVIOUS RAIN AND
MELTING SNOW SHOULD FREEZE UP WITH SOME NEW SNOW ACCUMULATIONS
LIKELY ON TOP OF THAT. BRISK WESTERLY LOW LEVEL FLOW SHOULD SEND
HEAVIER SNOW BANDS WELL INLAND WITH AN I-96 OR I-94 CONVERGENCE BAND
POSSIBLE.

FORECAST CONFIDENCE IS CURRENTLY LOW FOR NEXT WEDNESDAY AND THURSDAY
AND THE PEAK HOLIDAY TRAVEL PERIOD. MODEL SOLUTIONS HAVE NOT BEEN
CONSISTENT FOR THIS PERIOD ALTHOUGH IT DOES LOOKS LIKE H5 TROUGHING
ALOFT WILL PROBABLY PERSIST. THIS IMPLIES A CONTINUED THREAT OF COLD
AIR INTRUSIONS FROM THE NORTHWEST WITH MORE BOUTS OF LAKE EFFECT
SNOWS POSSIBLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1205 AM EST FRI NOV 21 2014

LAKE EFFECT SNOW SHOWERS WILL BE ENDING WITH VFR BY 08Z. WINDS WILL
DIMINISHING AS WELL AND GOING SOUTHWEST FRIDAY AFTERNOON AROUND 10
KNOTS.


&&

.MARINE...
ISSUED AT 326 AM EST FRI NOV 21 2014

WE HAVE EXTENDED THE SMALL CRAFT ADVISORY OUT A FEW MORE HOURS UNTIL
15Z THIS MORNING. THE LATEST WAVES AT THE MID LAKE BUOY COMBINED
WITH THE LATEST WAVE GUIDANCE INDICATES THAT WAVES WILL NOT DROP
DOWN BELOW CRITERIA UNTIL MID MORNING.

THE NEXT EVENT OF CONCERN IS THEN BEGINNING TONIGHT AND LASTING
THROUGH MUCH OF THE WEEKEND. THE GRADIENT WILL TIGHTEN UP AHEAD OF
THE SYSTEM THAT WILL BE AFFECTING THE AREA THIS WEEKEND. A GOOD
AMOUNT OF WIND ALOFT WILL BE MOVING OVERHEAD...HOWEVER IT DOES NOT
LOOK LIKE IT WILL EASILY BE BROUGHT DOWN SINCE MUCH WARMER AIR WILL
BE RIDING OVER THE COOLER WATERS OF LAKE MICHIGAN. THIS IS ANOTHER
SOLID ADVISORY EVENT AT THE LEAST...HOWEVER THERE IS A CHANCE OF
SOME GALES. WE WILL LET THIS EVENT FINISH UP BEFORE ISSUING ANOTHER
ADVISORY FOR THE NEXT EVENT.

&&

.HYDROLOGY...
ISSUED AT 321 PM EST THU NOV 20 2014

WE ARE STILL MONITORING THE FLOOD THREAT OVER THE WEEKEND AS
AROUND A INCH OF RAIN IS EXPECTED TO FALL OVER OUR CURRENT SNOW
PACK. THE LATEST GUIDANCE FROM THE NCRFC INDICATES NONE OF OUR
RIVERS WILL RISE TO OR ABOVE FLOOD STAGE BUT WE MAY WELL HAVE SOME
MINOR URBAN AND SMALL STREAM FLOODING NONE THE LESS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR
LMZ844>849.

&&

$$

SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...NJJ




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