Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 031716
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1215 PM EST TUE MAR 3 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 AM EST TUE MAR 3 2015

LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES TODAY BRINGING A
VARIETY OF WEATHER TYPES...ALL OF WHICH WILL MAKE ROADS A BIT MESSY.
SNOW...FREEZING RAIN...SLEET...AND RAIN ARE ALL EXPECTED TODAY WITH
THE RAIN LIKELY THE LAST TO DEVELOP SOUTH OF I-94 THIS AFTERNOON.
SNOWFALL FROM 1-4 INCHES...HIGHEST NORTH OF M-46...WILL ACCUMULATE
PRIOR TO DIMINISHING TONIGHT. ANOTHER SHOT OF ARCTIC AIR...PERHAPS
THE LAST...WILL RESULT IN HIGHS IN THE TEENS THURSDAY. TEMPERATURES
WILL RISE INTO THE 30S OVER THE WEEKEND.

&&

.UPDATE...
ISSUED AT 1145 AM EST TUE MAR 3 2015

CONTINUING THE WINTER WEATHER ADVISORY THROUGH 800 PM THIS
EVENING. PRECIPITATION HAS CHANGED OVER TO A MIX FOR ABOUT THE
SOUTHERN HALF OF THE FORECAST AREA. DUAL POL CORRELATION
COEFFICIENT HAS DEPICTED THE CHANGE OVER LINE WELL FROM ALL SNOW
TO A MIX OF SLEET AND FREEZING RAIN THIS MORNING. THIS LINE HAS
DRIFTED STEADILY NORTHWARD THROUGH THE COURSE OF THE MORNING AND
NOW LIES JUST NORTH OF THE INTERSTATE 96 CORRIDOR. EXPECTING THE
MIX TO TAPER TO DRIZZLE AND FREEZING DRIZZLE THIS AFTERNOON ACROSS
THE SOUTHERN HALF OF THE FORECAST AREA. SOME SNOW WILL CONTINUE
ACROSS CENTRAL LOWER BEFORE TAPERING/TRENDING TOWARDS FREEZING
DRIZZLE AS WELL.

THE BACK EDGE OF THE HEAVIER PRECIPITATION IS ALREADY COMING
ASHORE OFF OF LAKE MICHIGAN AT 1130AM AND SHOULD BE EXITING THE
EASTERN CWA ALONG U.S. 127 BETWEEN 230PM AND 300PM.

WE WILL TAKE A CLOSE LOOK AT THE FREEZING DRIZZLE THREAT THIS
AFTERNOON AND MAKE ANY NECESSARY CHANGES TO THE HEADLINE WITH THE
AFTERNOON FORECAST UPDATE. AT THIS POINT PLANNING ON KEEPING THE
HEADLINE INTO THE EVENING GIVEN THE LIGHT HAZE LOOK ON UPSTREAM
RADARS WHICH USUALLY CORRELATES TO FREEZING DRIZZLE. THE DGZ
RAPIDLY BECOMES UNSATURATED THIS AFTERNOON. FREEZING DRIZZLE
SHOULD REMAIN LIKELY AT LEAST THROUGH THE EVENING COMMUTE HOME
FROM WORK AND SCHOOL.

THE HIGHER SNOWFALL TOTALS RECEIVED THUS FAR ARE NEAR 3 INCHES
ACROSS THE GRAND RAPIDS AREA.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 328 AM EST TUE MAR 3 2015

FORECAST CONCERNS DEAL WITH THE WINTER WEATHER THAT IS JUST
DEVELOPING OVER THE WESTERN GREAT LAKES. THE SHORT RANGE MODELS HAVE
BEEN PRETTY CONSISTENT OVER THE PAST 4 DAYS WITH THE MIXED PCPN
SCENARIO AND CONFIDENCE IS FAIRLY HIGH. AS SUCH...LITTLE CHANGE WAS
NEEDED TO THE GOING FORECAST AND THE HEADLINE REMAINS INTACT.

WE/LL SAY AT THE OUTSET THOUGH THAT THE MODELS SEEM TO HAVE OVERDONE
THE INITIAL COLD AIR; WE JUST HAVEN`T DROPPED TEMP WISE LIKE
ADVERTISED. SO THE UPSIDE TO THAT IS THAT WE MAY SEE LESS IN THE WAY
OF FREEZING RAIN. HOWEVER...GIVEN DEWPOINTS IN THE MID TEENS...
EVAPORATIVE COOLING WILL LOWER TEMPS A BIT AS PCPN DEVELOPS.

STRONG ISENTROPIC LIFT IS ONGOING OVER THE MIDWEST AND AS THE COLUMN
SATURATES WE`VE WATCHED PCPN DEVELOP LAST NIGHT OVER NORTHERN
MISSOURI AND MOVE NORTHEAST TO ILLINOIS. LIGHT SNOW HAS DEVELOPED
DURING THE PAST HOUR OR SO AT MUSKEGON AND FREMONT AND WILL CONTINUE
TO DEVELOP OVER THE REST OF THE CWA TOWARD MORNING.

A VERY STRONG 180KT UPPER JET WILL QUICKLY MOVE LOW PRESSURE FROM
THE PLAINS TOWARD LOWER MICHIGAN WHERE IT WILL PHASE WITH THE LOW IN
CANADA. A 65KT LLJ WILL DRAW WARM AIR NORTHWARD INTO THE SYSTEM AND
THAT WILL ENABLE A CHANGE FROM SNOW TO SOME SLEET AND FREEZING RAIN.
THE ECMWF/GFS/NAM ARE ALL A LITTLE DIFFERENT IN THERE THERMAL
PROFILES AND AS A RESULT GIVE SLIGHTLY DIFFERING AMOUNTS OF
SNOW/SLEET/FREEZING RAIN. GIVEN THE SLIGHTLY WARMER STARTING TEMPS
WE TRIMMED ICE ACCUMULATION AMOUNTS A BIT OVER THE SOUTHERN CWA.
STILL LOOKING AT A CHANGE OVER TO FREEZING RAIN AND RAIN SOUTH OF
I-96. EVEN WITH TEMPS ABOVE FREEZING...GRAVEL ROAD TEMPS MAY STILL
REMAIN BELOW FREEZING AND CREATE ICY CONDITIONS.

THERE/S LIKELY TO BE A BIT MORE SLEET CLOSER TO I-96 WITH MOSTLY
SNOW NORTH OF M-46. SNOWFALL ACCUMS SHOULD RANGE FROM 1-3 INCHES
SOUTH OF I-96 TO 2 TO 4 INCHES NORTH OF THERE PRIOR TO THE
DEVELOPMENT OF THE FREEZING RAIN/SLEET.

A FAIRLY STRONG DRY SLOT DEVELOP AROUND 00Z TONIGHT AND THE DGZ
BECOME UNSATURATED. ANY LINGERING PCPN WILL MIX WITH FREEZING
DRIZZLE THIS EVENING. WINDS WILL ALSO INCREASE THIS EVENING AFTER
THE COLD FRONT MOVES THROUGH AND H8 TEMPS START TO TUMBLE. LAKE
EFFECT SNOW SHOWERS WILL DEVELOP LATE TONIGHT AND CONTINUE WEDNESDAY
AND THURSDAY. THE CORE OF THE COLD AIR WILL BE OVER THE CWA THURSDAY
AND HIGHS WILL ONLY CLIMB INTO THE TEENS...NEARLY 25 DEGREES BELOW
NORMAL.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 328 AM EST TUE MAR 3 2015

THE LONG TERM PERIOD LOOKS GENERALLY QUIET WITH ONLY PERIODIC
CHANCES OF LIGHT SNOW SHOWERS. TEMPERATURES WILL STILL BE BELOW
NORMAL BUT NOT NEARLY AS COLD AS WHAT WE HAVE SEEN OVER THE LAST
MONTH.

ONE MORE VERY COLD NIGHT IS EXPECTED THURSDAY NIGHT WITH LOW
TEMPERATURES NEAR ZERO BEFORE A MODERATING TREND DEVELOPS. TIGHT
GRADIENT ON THE BACK SIDE OF THE DEPARTING SFC HIGH USHERS IN MILDER
AIR FROM THE SOUTHWEST FOR FRIDAY...ALTHOUGH HIGHS STILL ONLY IN THE
20S WITH BREEZY CONDITION.

WEAK SFC COLD FRONTS ARE PROGGED TO SLIP THROUGH THE REGION ON BOTH
SATURDAY AND MONDAY RELATED TO CLIPPER SYSTEMS PASSING BY TO OUR
NORTH. THESE FRONTS MAY PRODUCE SOME LIGHT SNOW SHOWERS BUT LITTLE
OR NO SNOW ACCUMULATION EXPECTED. THE FRONTS WILL ALSO PREVENT ANY
REAL WARM UPS THROUGH EARLY NEXT WEEK. HOWEVER THERE CONTINUES TO BE
A STRONG SIGNAL OF A POTENTIALLY SIGNIFICANT WARM UP BY LATE NEXT
WEEK AS UPR RIDGING BUILDS OVER THE REGION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY)
ISSUED AT 1215 PM EST TUE MAR 3 2015

THE HEAVIEST PRECIPITATION HAS MOVED OFF TO THE EAST BUT IFR
CONDITIONS ARE LIKELY TO CONTINUE THIS AFTERNOON DUE TO EXTENSIVE
LOW CLOUD COVER AND LIGHT FREEZING RAIN/SLEET/LIGHT SNOW.

WINDS WILL CONTINUE TO GRADUALLLY INCREASE AND BY MID TO LATE
AFTERNOON SW WINDS WILL GUST TO AROUND 25 KTS. SOME AREAS OF
FREEZING DRIZZLE ARE ANTICIPATED THIS EVENING ALONG WITH GUSTY WEST
WINDS.

CONDITIONS WILL GRADUALLLY IMPROVE TO MVFR LATE TONIGHT AS CIGS AND
VISBYS SLOWLY IMPROVE. CONDITIONS SHOULD CONTINUE TO IMPROVE TO VFR
FOR WEDNESDAY.

&&

.HYDROLOGY...
ISSUED AT 1205 AM EST MON MAR 2 2015

AREA STREAMS AND RIVERS REMAIN STABLE WITH NO NOTABLE VARIATIONS
TO RAISE CONCERNS. THE OVERALL THINKING WITH THE FORECAST IS
CONSISTENT WITH PRIOR STATEMENTS IN THE LAST 48 HOURS.

SEE-SAW TEMPERATURES ARE EXPECTED OVER THE NEXT SEVERAL DAYS WITH
30S TUESDAY...RETURNING TO THE TEENS AND 20S WEDNESDAY THROUGH
FRIDAY. THE STORM SYSTEM TUESDAY BRINGS THE BULK OF THE MOISTURE
BEFORE CONDITIONS BECOME RELATIVELY TAME FOR THE REMAINDER OF THE
WEEK. QPF IS EXPECTED TO BE AROUND ONE-HALF AN INCH OR LESS AS THE
STORM EXITS LATE TUESDAY. MILDER TEMPERATURES ARE SHORT-LIVED AND
ARE ONLY BEING CONSIDERED MILD IN RELATIVE TERMS. SNOW ALREADY ON
THE GROUND SHOULD SOAK UP MUCH OF WHAT FALLS AS RAIN OR FREEZING
RAIN. ANY RIVER RESPONSE SHOULD HOLD OFF UNTIL WE GET A MORE
SUSTAINED AND ROBUST WARM PERIOD. FOR THAT...IT MAY NOT BE UNTIL
NEXT WEEK. THAT WILL BE SOMETHING TO CONSIDER IN DETAIL AS THE
WEEK PROGRESSES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
     MIZ037>040-043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...DUKE
SYNOPSIS...99
SHORT TERM...99
LONG TERM...MEADE
AVIATION...LAURENS
HYDROLOGY...JAM







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