Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 291026
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
526 AM EST MON DEC 29 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 304 AM EST MON DEC 29 2014

THIS WEEK WILL BE COLD WITH HIGHS MOSTLY IN THE 20S. WEDNESDAY WILL
BE THE COLDEST DAY WITH HIGHS AROUND 20 AND WIND CHILLS BELOW 0.
OCCASIONAL FLURRIES WILL FALL TODAY AS WEAK LOW PRESSURE ALOFT MOVES
ACROSS MICHIGAN. A BETTER CHANCE FOR LIGHT SNOW WILL OCCUR TUESDAY
WEST OF US-131 AS A STRONG COLD FRONT MOVES THROUGH. AN INCH OR TWO
OF ACCUMULATION IS POSSIBLE TUESDAY NEAR THE LAKE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 304 AM EST MON DEC 29 2014

FORECAST CONCERNS DEAL WITH LIGHT SNOW CHANCES AS A STRONG COLD
FRONT MOVES THROUGH THE CWA TUESDAY.

MUCH COLDER AND NOT SO SNOWY IS THE WAY IT LOOKS FOR THIS WEEK.
LATEST REGIONAL RADAR SHOWS LIGHT RETURNS MOVING EAST FROM IOWA.
THIS IS ASSOCIATED WITH A MINOR SHORT WAVE AND SFC OBS DON/T REVEAL
MUCH MORE THAN FLURRIES. THE ISSUE WITH THIS SYSTEM IS REALLY WHAT
WE/LL DEAL WITH THROUGH THE PERIOD. THERE ISN/T MUCH IN THE WAY OF
LOW LEVEL MOISTURE...AND LOOKING AT BUFKIT RH PROFILES...THAT WILL
CONTINUE THROUGH WEDNESDAY. SO DESPITE A DECENT AMOUNT OF COLD AIR
IN PLACE...AND A STRONG COLD FRONT MOVING SOUTH TUESDAY IN WHICH H8
TEMPS FALL TO -19C BEHIND IT...WE DON/T EXPECT MUCH IN THE WAY OF
SNOW SHOWERS. MOST OF WHAT FALLS WILL BE CLOSER TO THE LAKE...WHERE
MODELS HAVE A DIFFICULT TIME ADJUSTING FOR MOISTURE ENTRAINMENT FROM
THE LAKE. WE DO HAVE HIGHER POPS THERE TUESDAY INTO WEDNESDAY AND
MINOR ACCUMULATIONS ARE POSSIBLE. ELSEWHERE THOUGH...FLURRIES SEEMS
LIKE THE WAY TO GO.

WEDNESDAY WILL BE COLD...HIGHS ONLY AROUND 20. GUSTY NORTHWEST WINDS
BEHIND THE DEPARTING COLD FRONT WILL RESULT IN APPARENT TEMPERATURES
OF 5 ABOVE TO 5 BELOW.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 304 AM EST MON DEC 29 2014

THE LONG TERM PERIOD WILL START OFF WITH WINDY AND COLD CONDITIONS.
BASED ON MIXING HEIGHTS AND FORECASTED WINDS AT THESE LEVELS...GUSTS
OVER 30 MPH ARE LIKELY TO OCCUR. THE MAIN TIMEFRAME WOULD BE
WEDNESDAY NIGHT INTO THURSDAY.  INSTABILITY IS SHOWN TO EXIST AS THE
COLD AIR ADVECTS OVER LAKE MI.  THE DGZ IS SHOWN TO BE MOIST ALONG
WITH SOME LIFT.  THUS SNOW SHOWERS SHOULD EXIST...HOWEVER GIVEN THE
FAST FLOW AND LOW INVERSION HEIGHTS ACCUMULATIONS SHOULD BE
LIMITED.  WE WILL NEED TO MONITOR THE IMPACTS CLOSELY GIVEN THE
POTENTIAL FOR LOCALIZED STRONGER SNOW SHOWERS...GUSTY WINDS AND LOW
WIND CHILLS.

OVER THE WEEKEND...MODELS HAVE NOT SHOWN GOOD CONTINUITY FROM THE
PREVIOUS RUNS...SO CONFIDENCE IS LOW.  THE HIGH RES EURO NOW
FEATURES A WEAKER AND SLOWER WAVE TRACKING THROUGH THE MID MS VALLEY
SUN. THIS WOULD FAVOR LESS PRECIPITATION AND COLDER TEMPERATURES FOR
MI AS COMPARED TO THE GFS.  THE GFS IS FURTHER NORTH AND
WARMER...AND WOULD SUPPORT TEMPERATURES BECOMING WARM ENOUGH FOR A
SNOW TO RAIN SCENARIO.  WITH THE HIGH RES EURO STILL SUPPORTING THE
ONGOING FORECAST...WILL LARGELY KEEP THE FORECAST CLOSE TO THE
PREVIOUS FORECAST.  THUS WE WILL FEATURE RELATIVELY LOW POPS AND A
MAIN PRECIPITATION TYPE OF SNOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 522 AM EST MON DEC 29 2014

LAKE EFFECT SNOW SHOWERS WILL BE DEVELOPING THROUGH THE FORECAST
PERIOD. WITH A NORTHERLY FLOW...TYPICALLY THE IMPACT SNOW SHOWERS
END UP VERY CLOSE TO THE LAKESHORE..OR JUST OFFSHORE. THIS SHOULD
BE THE CASE. KMKG WILL BE THE TAF SITE CLOSEST TO THE SNOW BANDS.
RIGHT NOW IT IS FORECASTED THAT THE STRONGEST BANDS WILL REMAIN
WEST OF EVEN KMKG. LAT TONIGHT...AFTER 09Z SOME OF THOSE SNOW
BANDS MAY SHIFT EAST...CLOSE TO KMKG. THIS WILL NEED TO BE
MONITORED CLOSELY.

&&

.MARINE...
ISSUED AT 304 AM EST MON DEC 29 2014

FAIRLY LIGHT WINDS ARE EXPECTED TODAY. HOWEVER...A SCA MAY BE NEEDED
BY TUESDAY AS A COLD FRONT MOVES SOUTH THROUGH LOWER MICHIGAN.
NORTHWEST WINDS WILL INCREASE TO 15 TO 25 MPH WITH HIGHER GUSTS.


&&

.HYDROLOGY...
ISSUED AT 304 AM EST MON DEC 29 2014

THE NEXT WEEK WILL BE RATHER CHILLY...MUCH OF IT BELOW FREEZING. THE
MAIN HYDRO ISSUES WILL BE ICE DEVELOPMENT ON AREA RIVERS AND
STREAMS.

&&

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

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...MJS
AVIATION...MJS
HYDROLOGY...93
MARINE...93





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