Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 050824
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
326 AM EST FRI FEB 5 2016

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

.SYNOPSIS...
ISSUED AT 326 AM EST FRI FEB 5 2016

A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL LINGER TODAY AND AGAIN
FOR SATURDAY. A CLIPPER SYSTEM WILL BRING MIXED RAIN AND SNOW
SHOWERS SUNDAY FOLLOWED BY SNOW SHOWERS SUNDAY NIGHT THROUGH EARLY
TO MID NEXT WEEK. TEMPERATURES WILL AVERAGE ABOVE NORMAL THIS
WEEKEND AND MONDAY BEFORE COOLING TO BELOW NORMAL BY MID TO LATE
WEEK.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 326 AM EST FRI FEB 5 2016

A SFC TROF WILL BRING POTENTIAL FOR A FEW MORE LIGHT SNOW SHOWERS
AND FLURRIES THIS MORNING. AFTER PASSAGE OF THE SFC TROF BY MIDDAY
A FEW MORE LIGHT SNOW SHOWERS AND FLURRIES WILL DEVELOP AS
THETA E DECREASES WITH HEIGHT RESULTING IN A LITTLE BIT OF
INSTABILITY. HOWEVER VERY LITTLE (UNDER AN INCH) TO NO SNOW
ACCUMULATION IS ANTICIPATED TODAY.

FAIR WX IS ANTICIPATED THIS EVENING FOLLOWED BY DEVELOPMENT OF A
FEW MORE LIGHT SNOW SHOWERS AND FLURRIES OVER OUR FAR NW FCST AREA
TOWARD DAYBREAK SATURDAY AS THE NEXT LOW PRESSURE SYSTEM CONTINUES
TO MOVE EAST ACROSS THE LAKE SUPERIOR REGION. THIS SYSTEM WILL
BRING POTENTIAL FOR A FEW LIGHT SNOW SHOWERS AND FLURRIES SATURDAY
MORNING AND AFTERNOON BUT ONCE AGAIN WITH VERY LITTLE TO NO SNOW
ACCUMULATION.

DRY WX RETURNS SATURDAY NIGHT BEFORE A CLIPPER SYSTEM BRINGS
POTENTIAL FOR A MIX OF RAIN AND SNOW SHOWERS SUNDAY AS THERMAL
PROFILES MODERATE IN SW FLOW WAA IN ADVANCE OF THE CLIPPER. HIGH
TEMPS SUNDAY WILL REACH THE UPPER 30S UP NORTH TO THE LOWER 40S
SOUTH.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 326 AM EST FRI FEB 5 2016

THERE IS LITTLE QUESTION THIS COMING WEEK WILL START OUT WARMER THAN
NORMAL BUT A SURGE OF ARCTIC AIR WILL BRING TEMPERATURES BELOW
NORMAL FOR WEDNESDAY AND THURSDAY. THERE IS ALSO LITTLE QUESTION
THERE WILL BE SNOW NEARLY EVERY DAY THIS COMING WEEK. THE MAIN
QUESTION IS HOW MUCH SNOW?

THE MODELS CONTINUE TO COME INTO BETTER AGREEMENT AS TO HOW THAT
LARGE SYSTEM THE CLOSES OFF AT UPPER LEVEL LOW OVER THE GREAT LAKES
WILL PLAY OUT IN TIME. OVERALL OUR TWO EAST ASIAN JET STREAKS...BOTH
OVER 180 KNOTS HELP TO DEVELOP A LARGE WEST COAST UPPER LEVEL RIDGE.
THAT HELPS THE SYSTEM NOW MOVING ON SHORE OVER WESTERN CANADA AND
THE PACIFIC NORTHWEST TO DIG STRONGLY TO THE SOUTHEAST. SEEMS SOME
OF THAT JET ENERGY MAKES IT UP THE EAST SIDE OF THE SYSTEM OVER THE
GULF OF ALASKA LEADING TO A 170 KNOT JET CORE HEADING TOWARD THE
EXTREME SOUTHEASTER PART OF ALASKA ON SUNDAY. THAT ONLY HELPS BUILD
THE UPPER RIDGE EVEN MORE SO. WE THEN HAVE A 150 KNOT JET CORE
DIVING DOWN THE WEST SIDE OF THE DEEPENING CENTRAL CONUS TROUGH. BY
MONDAY MORNING A LARGE UPPER LOW DEVELOPS OVER MICHIGAN  AND REMAINS
NEAR MICHIGAN INTO TUESDAY.  OUR SECOND EAST ASIAN JET CORE REACHES
THE DATELINE BY MONDAY NIGHT... FORCING SOME OF THE ENERGY FROM THE
STORM IN THE GULF OF ALASKA OVER THE WESTERN RIDGE. THAT FINALLY
PUSHES THE UPPER LOW OVER MICHIGAN TO THE EAST IN THE WEDNESDAY TIME
FRAME.

SINCE THE SYSTEM STALLS OVER MICHIGAN MONDAY...IT TAKES TILL TUESDAY
FOR THE ARCTIC AIR TO START TO MOVE INTO MICHIGAN. MEANWHILE WHAT WE
WILL HAVE TO WATCH IS WILL THE ECMWF BE CORRECT OR THE GFS IN TERMS
OF WHAT THE 700 MB LOW DOES.  THE GFS OPENS IT UP QUICKLY AND SO ON
MONDAY THE DEEP MOISTURE IS OVER LAKE MICHIGAN AND LAKE HURON.
MEANWHILE THE ECMWF IS MUCH SLOWER TO OPEN UP THE 700 MB LOW SO WE
REMAIN IN THE DEEP MOISTURE INTO TUESDAY. I WENT WITH THAT IDEA AS
THE GFS TYPICALLY OPENS THESE SYSTEM TO QUICKLY. WITH THE ECMWF IDEA
WE WOULD HAVE A STEADY SNOW EVENT MONDAY INTO TUESDAY MORNING BEFORE
THE LAKE EFFECT KICKS IN.

BOTH MODELS SHOW THE LAKE EFFECT KICKING IN TUESDAY AND LASTING
THROUGH THURSDAY. THIS WILL BE A NORTHWEST FLOW TYPE EVENT AND WITH
850 TEMPS GETTING TO NEAR -20C... THE DGZ WILL BE NEAR THE GROUND...
SO SNOW FLAKE SIZE WILL BE SMALL. STILL IT WOULD BE PROLONGED EVENT
SO WE COULD SEE OVER A FOOT OF SNOW I LAKE SHORE AREAS BY THE END OF
THE WEEK. I HAVE HIGH POPS WEST OF US-131 TUE THROUGH THURSDAY FOR
THIS.

.WEEK TWO OUTLOOK...

THE NEXT THING TO WATCH IS A SECOND PUSH OF EVEN COLDER AIR... IF
THIS AIR CAN REACH US...EARLY IN THE FOLLOWING WEEK IT WOULD BY FAR
BE THE COLDEST AIR OF THE SEASON. 850 MB TEMPS ARE NEAR -30C WITH
THIS EVENT. THERE COULD BE A VALENTINES DAY SNOWSTORM WITH THIS TOO.
IT WILL DEPEND ON HOW MUCH THE MJO CAN KEEP A SECOND DEEP EASTERN
TROUGH FROM FORMING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1204 AM EST FRI FEB 5 2016

ALL SITES ARE CURRENTLY VFR AT 05Z. AN UPSTREAM WEATHER
DISTURBANCE WILL SPREAD CLOUDS IN OVER THE COURSE OF THE REMAINDER
OF THE NIGHT. MVFR CEILINGS WILL FIRST SPREAD INTO KMKG LATE
TONIGHT...AND INTO THE OTHER TAF SITES THROUGH THE COURSE OF THE
DAY ON FRIDAY. THERE IS SOME LIGHT SNOW ASSOCIATED WITH THE
DISTURBANCE...BUT OUTSIDE OF KMKG...NOT EXPECTING MUCH IN THE WAY
OF RESTRICTION TO VISIBILITY INLAND. THE MVFR CEILING MAY BE
FAIRLY PREVALENT FRIDAY AFTERNOON AND EARLY EVENING BEFORE WE
TREND VFR ONCE AGAIN FRIDAY EVENING. WINDS WILL BE LESS THAN 10
KNOTS THROUGH THE PERIOD.


&&

.MARINE...
ISSUED AT 326 AM EST FRI FEB 5 2016

WINDS AND WAVES WILL REMAIN RELATIVELY LIGHT THROUGH TONIGHT. SW
WINDS WILL INCREASE A BIT SATURDAY.

&&

.HYDROLOGY...
ISSUED AT 258 PM EST WED FEB 3 2016

MINOR FLOODING IS POSSIBLE THIS WEEK... ESPECIALLY IN LOWLAND AREAS
NEAR RIVERS. SOME RIVERS MAY EXCEED BANKFULL DUE TO SNOW MELT AND
PRECIPITATION FROM THE LAST STORM. TOTAL PRECIPITATION OF ONE TO
AROUND ONE AND A HALF INCHES FELL. RIVER FLOOD ADVISORIES HAVE BEEN
ISSUED FOR SYCAMORE CREEK AT HOLT... FLAT RIVER AT SMYRNA... ROGUE
RIVER AT ROCKFORD... MAPLE RIVER AT MAPLE RAPIDS AND GRAND RIVER AT
IONIA.

&&

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

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...DUKE
HYDROLOGY...63
MARINE...LAURENS


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