Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 281145
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
745 AM EDT TUE OCT 28 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT TUE OCT 28 2014

RAIN SHOWERS WILL EXIT TO THE EAST THIS AFTERNOON AND BE FOLLOWED BY
BREEZY AND COOLER CONDITIONS AS A COLD FRONT SWEEPS THROUGH THE
REGION. TEMPERATURES ON WEDNESDAY AND THURSDAY WILL BE CLOSER TO
NORMAL FOR THE END OF OCTOBER WITH HIGHS AROUND 50.

VERY CHILLY AIR WILL ARRIVE ON HALLOWEEN AND WE MAY SEE OUR FIRST
SNOWFLAKES OF THE SEASON ALONG WITH STRONG NORTH WINDS. THE COLD AIR
WILL STICK AROUND ON SATURDAY THEN A MODERATING TREND IN
TEMPERATURES WILL BEGIN SUNDAY.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 330 AM EDT TUE OCT 28 2014

CONSENSUS OF SHORT RANGE GUIDANCE INDICATES THAT THE HIGHEST
COVERAGE OF RAIN SHOWERS THIS MORNING WILL BE SOUTH AND EAST OF GRR
AND WILL CARRY CATEGORICAL POPS ACROSS THIS AREA WITH MUCH LOWER
POPS NORTH OF GRR. THE COVERAGE OF TSTMS SHOULD BE QUITE LOW WITH MU
CAPES GENERALLY UNDER 500 J/KG.

THE ARRIVAL OF THE DRY SLOT THIS AFTERNOON BEHIND THE SFC COLD FRONT
WILL LEAD TO SOME SUNSHINE BUT THE DEEPER MIXING AND COLD ADVECTION
WILL ALSO PROMOTE SOME RATHER GUSTY WEST WINDS TO 35 MPH. WE HAVE
ACTUALLY SEEN A FEW OCCURRENCES OF STRONGER GUSTS ALREADY EARLY THIS
MORNING DUE TO THE 40 KT LOW LEVEL JET OVERHEAD AND THE SHOWERS
HELPING TO BRIEFLY MIX THIS DOWN.

LESS WIND ON WEDNESDAY BUT SCATTERED LAKE EFFECT RAIN SHOWERS
EXPECTED AS LOW LEVEL MOISTURE BETWEEN 2K AND 5K DROPS IN FROM THE
NORTHWEST. H8 TEMPS FALL TO AROUND -3C AND CYCLONIC FLOW WILL BE IN
PLACE SO A MORE TYPICAL OCTOBER DAY WITH EXTENSIVE STRATOCUMULUS AND
OCCASIONAL LIGHT SHOWERS ESPECIALLY ALONG/WEST OF HIGHWAY 131.

SFC RIDGE ARRIVES WEDNESDAY NIGHT AND THURSDAY ALTHOUGH EXTENSIVE
LOW CLOUDINESS MAY LINGER UNDER THE SUBSIDENCE INVERSION AS IS
TYPICAL IN MICHIGAN IN LATE OCTOBER.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 AM EDT TUE OCT 28 2014

FORECAST CONCERNS DURING THE LONG TERM CONTINUE TO REVOLVE AROUND
THE STRONG COLD FRONT FRIDAY. THE MODELS ARE CONVERGING ON A
SOLUTION IN WHICH H8 TEMPS FALL TO -8C BY FRIDAY AFTERNOON. THE
STRENGTH OF THIS SYSTEM SEEMS TO RELY ON THE TIMING OF TWO SHORT
WAVES PHASING OVER THE GREAT LAKES. THE FIRST IS A WAVE THAT MOVES
IN OFF THE PACIFIC ACROSS THE ROCKIES AND THEN MOVES SOUTHEAST
TOWARD THE MISSOURI VALLEY. THE SECOND AND STRONGER WAVE MOVES SOUTH
FROM NORTHERN CANADA AND ACROSS LAKE SUPERIOR AROUND THE TIME THE
FIRST WAVE MOVES ACROSS THE MISSISSIPPI. THE RESULT IS A DEEPENING
UPPER TROUGH AND SFC LOW THAT MOVES FROM LAKE SUPERIOR SEWD ACROSS
LAKE HURON. STRONG NORTH WINDS DEVELOP AS THE COLD FRONT MOVES
THROUGH FRIDAY MORNING. MODELS SHOW QUITE A BIT OF WRAP AROUND
MOISTURE WITH THE LOW. GIVEN THE STRENGTH OF THE COLD AIR
ADVECTION...WE SHOULD SEE MIXED RAIN AND SNOW SHOWERS THROUGHOUT THE
DAY. HIGHS ARE LIKELY TO BE IN THE MORNING WITH MOSTLY 30S IN THE
AFTERNOON. IT/S GOING TO FEEL REALLY CHILLY TOO WITH A BRISK NORTH
WIND. THERE COULD BE LINGERING LAKE EFFECT SNOW SHOWERS FRIDAY NIGHT
ALONG THE COAST...BUT NORTH WIND AND SHALLOW MOISTURE WILL PROHIBIT
ANY SIGNIFICANT PCPN.

HIGH PRESSURE THEN MOVES OVERHEAD LEADING TO FAIR SKIES FOR THE
WEEKEND...BUT HIGHS ONLY IN THE LOWER TO MID 40S. TEMPS WILL CLIMB
INTO THE 50S EARLY NEXT WEEK AS THE HIGH MOVES EAST AND SOUTH WINDS
DEVELOP.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE OCT 28 2014

A PERIOD OF MVFR CIGS/VSBYS CAN BE EXPECTED THIS MORNING AS THE
SFC COLD FRONT PRESSES EAST THROUGH THE AREA. TEMPORARY IFR
CONDITIONS ARE ALSO POSSIBLE IN THE AREAS OF HEAVIER RAIN AHEAD OF
THE FRONT. DID NOT INCLUDE ANY TSTMS/CBS IN THE TAFS BUT A STORM
CANNOT BE COMPLETELY RULED OUT THROUGH 15Z MAINLY SOUTH AND EAST
OF GRR.

VFR CONDITIONS WILL DEVELOP WITH FROPA FROM WEST TO EAST LATER
THIS MORNING BETWEEN ROUGHLY 14Z AND 18Z. HOWEVER SFC WINDS WILL
ALSO INCREASE OUT OF THE WEST-SOUTHWEST DURING THIS TIME AND GUSTS
AS HIGH AS 30-35 KNOTS ARE LIKELY AFTER 18Z. THE WINDS SHOULD
RELAX AFTER 00Z TONIGHT.

&&

.MARINE...
ISSUED AT 330 AM EDT TUE OCT 28 2014

STRONG WEST WINDS TO 30 KNOTS TODAY AND TONIGHT THEN NORTHWEST ON
WEDNESDAY WITH WAVES TO 8 FEET WILL BE HAZARDOUS TO SMALL CRAFT. A
SIGNIFICANT NORTH FLOW EVENT IS LOOKING LIKELY FOR HALLOWEEN WITH
GALES A GOOD BET.

&&

.HYDROLOGY...
ISSUED AT 1149 AM EDT MON OCT 27 2014

THE OVERALL TREND THIS WEEKEND HAS BEEN TO GRADUALLY STEP BACK ON
PRECIP TOTALS. IT SEEMS THAT THE CHANCES FOR ANY HIGHER TOTALS
IS LOW AND WOULD BE THE OUTLIER. I SUPPOSE SOME LOCALIZED AREAS
WOULD EXCEED HALF AN INCH OR SO IF AFFECTED BY THUNDERSTORMS
TONIGHT...JUST AS THEY HAD IN NORTHERN SECTIONS OF THE FORECAST
AREA THIS MORNING. THIS SHOULD NOT LEAD TO ANY FLOODING ISSUES.
RIVERS ARE ALREADY RUNNING WELL WITHIN THEIR BANKS. WITH RECENT
DRY WEATHER ANY INCOMING PRECIP WOULD JUST BE BENEFICIAL AT THIS
POINT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT WEDNESDAY FOR LMZ844>849.

&&

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...93
AVIATION...MEADE
HYDROLOGY...JAM
MARINE...MEADE






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