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000
FXUS63 KGRR 120134
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
934 PM EDT TUE MAR 11 2014

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 302 PM EDT TUE MAR 11 2014

A DEEPENING LOW PRESSURE SYSTEM WILL TRACK UP THE OHIO VALLEY
TONIGHT INTO WEDNESDAY. THIS SYSTEM WILL PRODUCE A BAND OF HEAVIER
SNOW THAT WILL IMPACT MUCH OF SOUTHERN LOWER MICHIGAN. A MUCH
COLDER AIRMASS WILL MOVE IN BEHIND THIS STORM AND PERSIST ACROSS
THE REGION THROUGH THURSDAY.

&&

.UPDATE...
ISSUED AT 934 PM EDT TUE MAR 11 2014

WE WILL BE MAINTAINING THE CURRENT SET OF HEADLINES THIS EVENING
FOR THE STORM SYSTEM COMING IN TONIGHT WITH NO REAL CHANGES TO THE
FCST FOR NOW.

BATCH OF PCPN COMING THROUGH THIS EVENING HAS BEEN ALL RAIN THUS
FAR ACROSS THE CWFA. MILD AIR REMAINS IN PLACE AND DEEP ENOUGH FOR
MOST OF THE AREA. WE EXPECT THIS BATCH OF PCPN TO MOVE OUT OVER
THE NEXT HOUR OR SO BEFORE THE MAIN BATCH COMES IN A FEW HOURS AS
THE PHASING OF THE SYSTEMS TAKE PLACE. WE EXPECT THAT THE COLDER
AIR IS ON TRACK TO CHANGE ALL PCPN OVER TO SNOW FROM N TO S OVER
THE ENTIRE AREA BY AROUND 06Z.

WE ARE CURRENTLY IN A HOLDING PATTERN...WAITING TO SEE WHERE THE
BEST FGEN BANDS OF PCPN WILL SET UP OVERNIGHT. MODELS ARE ALL IN
GENERAL AGREEMENT WITH THE TRACK OF THE PHASED WAVES. STILL SOME
DISAGREEMENT WITH THE BACKEDGE OF PCPN THAT WILL BE ON THE NORTH
SIDE OF THE FGEN CIRCULATION WHERE THE SINKING AIR WILL OCCUR.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 302 PM EDT TUE MAR 11 2014

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE HEADLINE CHANGES.
OVERALL A TREND A SLIGHTLY FURTHER SOUTH TREND OF THE LOW TRACK IS
SEEN. STILL NOT CERTAIN HOW THIS ONE WILL PLAY OUT...AS THE ARE
SEVERAL INGREDIENTS THAT TRY TO COME TOGETHER ACROSS THE CWA AS
THE STORM PUSHES THROUGH. WE MAY STILL NEED TO MODIFY HEADLINES
THIS EVENING DEPENDING ON TRENDS.

IT FAIRLY CLEAR THAT A BAND OF HEAVIER SNOW WILL DEVELOP OVER
PARTS OF SOUTHERN LOWER MI AS THE MODELS SHOWING STRONGER MID
LEVEL FGEN...WEAKNESS IN THE STABILITY ALONG WITH A COUPLED UPPER
JET. WE ARE SEEING DRIER AIR MOVING DOWN FROM THE NORTH. I SEE
THIS DRY AIR AND THE STRUCTURE OF THE STABILITY AS SUPPORTING A
SHARP EDGE TO THE SNOW ACCUMULATIONS. I AM FAIRLY CERTAIN WE WILL
SEE AN INCH PER HOUR RATES DURING THE MORNING COMMUTE ESPECIALLY
ALONG I-94. BATTLE CREEK TO JACKSON SHOULD SEE A LONGER DURATION
OF THE HEAVIER SNOW SO I FEATURED THEM IN A WARNING. FURTHER NORTH
AND WEST ACCUMULATIONS SHOULD END UP LESS...BUT IMPACTS ARE LIKELY
GIVEN SEVERAL INCHES OF SNOW AND FALLING TEMPERATURES. ROAD
CONDITIONS ARE ALREADY MOIST THROUGH MUCH OF THE AREA...SO ICY
CONDITIONS COULD START OFF BY MIDNIGHT...EVEN WITHOUT SNOW. I-94
SHOULD STAY ABOVE FREEZING THROUGH MUCH OF THE EVENING...BUT BY 2
OR 3 AM...THEY SHOULD FALL BELOW FREEZING.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 302 PM EDT TUE MAR 11 2014

NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST. A CLIPPER SYSTEM
MOVING ACROSS THE AREA FRIDAY WILL WILL ALLOW TEMPERATURES TO
REBOUND TO NEAR SEASONAL VALUES DURING THE DAY. THIS WILL BE
FOLLOWED BY A SHOT OF LAKE EFFECT SNOW FRIDAY NIGHT INTO EARLY
SATURDAY NORTH OF INTERSTATE 96 WITH LITTLE ACCUMULATIONS EXPECTED.

AFTER THIS...HIGH PRESSURE AT THE SURFACE FOLLOWED BY RIDGING ALOFT
KEEPS CERTAINTY FAIRLY HIGH FOR DRY WEATHER LASTING INTO MONDAY.

TUESDAY CURRENTLY LOOKS MILD AND WET WITH BOTH THE ECWMF AND GFS
AGREEING ON BRINGING A DEEP PHASED UPPER TROUGH TOWARDS THE AREA
WITH AN ATTENDANT SURFACE LOW. HOWEVER...THIS IS NOT SUPPORTED AS
MUCH BY THE 11/00Z FIM...AND FORECAST CERTAINTY IN GENERAL DROPS OFF
VERY QUICKLY 6 TO 7 DAYS OUT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 757 PM EDT TUE MAR 11 2014

WIDESPREAD VFR CONDITIONS WERE STILL PRESENT EARLY THIS EVENING
AND WILL CONTINUE FOR A FEW MORE HOURS BEFORE TRENDING DOWN INTO
THE MVFR AND IFR CATEGORY TOWARD/AFTER 06Z.

CONFIDENCE IN PERSISTENT IFR CONDITIONS IN SNOW/HEAVY SNOW IS
HIGHEST SOUTH AND EAST OF GRR LATE TONIGHT AND EARLY WEDNESDAY FOR
AREAS SOUTH AND EAST OF GRR. LIFR IS ALSO POSSIBLE ESPECIALLY
AROUND JXN FROM 09Z-15Z DURING THE HEIGHT OF THE SNOWSTORM.

A SHARP NORTHERN EDGE TO THIS SYSTEM WILL PROBABLY LEAD TO LITTLE
OR NO SNOW AT MKG WITH CONDITIONS LIKELY REMAINING VFR. GRR SHOULD
BE THE CUTOFF BETWEEN SNOW/NO SNOW AND CONDITIONS AT THIS TERMINAL
COULD GO EITHER WAY.

NORTH WINDS WILL INCREASE AND BECOME STRONG/GUSTY LATE TONIGHT AND
EARLY WEDNESDAY...LEADING TO SOME BLOWING SNOW ISSUES MAINLY
SOUTH AND EAST OF GRR WHERE MOST OF THE SNOW IS EXPECTED TO FALL.


&&

.HYDROLOGY...
ISSUED AT 302 PM EDT TUE MAR 11 2014

RISES UNDERWAY AND TODAYS WARMER THAN EXPECTED TEMPERATURES ARE
ALLOWING FOR SOME ENHANCED RUNOFF. STILL WE ARE NOT EXPECTING ANY
HIGHER IMPACTS FROM THIS INITIAL SURGE OF RUNOFF. WITH ICE IN THE
RIVERS...WE STILL NEED TO MONITOR FORECAST POINTS CLOSELY.
TEMPERATURES WILL FALL WELL BELOW FREEZING ON WEDNESDAY AND THAT
SHOULD LOCK UP THE RUNOFF FOR A FEW DAYS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 3 PM EDT WEDNESDAY FOR MIZ057>059-
     064>067-071-072.

     WINTER STORM WARNING UNTIL 3 PM EDT WEDNESDAY FOR MIZ073-074.

LM...NONE.
&&

$$

UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...TJT
AVIATION...MEADE
HYDROLOGY...MJS