Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 031230
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
730 AM EST TUE MAR 3 2015

LATEST UPDATE...
MESOSCALE DISCUSSION/AVIATION

.MESOSCALE DISCUSSION...
ISSUED AT 730 AM EST TUE MAR 3 2015

STRONG RETURNS DEVELOPING ON RADAR JUST UPSTREAM OVER FAR NRN IL
IN AREA OF BEST ISENTROPIC ASCENT HAS RECENTLY PRODUCED MODERATE
SNOW AT ROCKFORD AND WAUKEGAN IL. LATEST SHORT TERM GUIDANCE
MOVES THIS RELATIVELY NARROW AXIS OF HEAVIEST PRECIP EAST-
NORTHEAST INTO SW LWR MI OVER THE NEXT FEW HOURS... SPECIFICALLY
TOWARD THE HOLLAND AND GRAND RAPIDS AREAS. LOOK FOR HEAVY SNOWFALL
RATES OF UP TO ONE INCH PER HOUR TO OCCUR IN THESE AREAS FROM
ROUGHLY 9 AM TO 1 PM... LIKELY EXPANDING TOWARD THE LANSING AND ST
JOHNS AREAS EVENTUALLY AS WELL.

&&

.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.

&&

.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 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 730 AM EST TUE MAR 3 2015

IFR/LIFR CONDITIONS WILL BECOME WIDESPREAD EARLY THIS MORNING AS
SNOW RAPIDLY DEVELOPS THEN MIXES WITH OR CHANGES TO FREEZING RAIN
AND SLEET LATER THIS MORNING AND THIS AFTERNOON. MODERATE TO
SEVERE ICING IS EXPECTED FROM THE SFC TO 20K FT... PARTICULARLY AS
THE HEAVIEST PRECIPITATION IS OCCURRING BETWEEN 14Z AND 20Z. THE
PRECIP SHOULD DIMINISH RAPIDLY AFTER 21Z TO JUST AREAS OF
DRIZZLE/FREEZING DRIZZLE. IMPROVEMENT IN CIGS/VSBYS EXPECTED AFTER
00Z AND ESPECIALLY AFTER 03Z.

INCREASING SOUTH WINDS TODAY WILL LEAD TO SOME LOW LEVEL TURBULENCE
DEVELOPING BY 18Z AND CONTINUING THROUGH THE AFTERNOON AND
EVENING. THE WINDS WILL SHIFT TO THE WEST-NORTHWEST AFTER 00Z BUT
REMAIN GUSTY THROUGH MUCH OF THE NIGHT.

&&

.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.
&&

$$

MESOSCALE...MEADE
SYNOPSIS...99
SHORT TERM...99
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JAM






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