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000
FXUS63 KGRR 281752
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1252 PM EST SAT FEB 28 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EST SAT FEB 28 2015

WEAK LOW PRESSURE WILL MOVE ACROSS SOUTHERN LOWER MICHIGAN THIS
EVENING AND SUNDAY SPREADING LIGHT SNOW AS IT MOVES EAST.
ACCUMULATIONS WILL BE LIMITED TO 1 TO PERHAPS 3 INCHES...HIGHEST
SOUTH OF I-94. A MORE SUBSTANTIAL SYSTEM WILL AFFECT LOWER MICHIGAN
MONDAY NIGHT AND TUESDAY. THE POTENTIAL EXISTS FOR MIXED FREEZING
RAIN...SLEET...AND SOME SNOW. TEMPERATURES WILL WARM INTO THE MID
30S TUESDAY BUT QUICKLY FALL INTO THE TEENS BY THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EST SAT FEB 28 2015

FORECAST CONCERNS DEAL WITH SNOW POTENTIAL TONIGHT/SUNDAY.
OVERALL...THE FORECAST DIDN/T CHANGE MUCH.

WE/LL START OFF MOSTLY SUNNY THIS MORNING BUT CLOUDS WILL BEGIN TO
SPREAD OVER THE CWA BY LATE IN THE AFTERNOON AS A COUPLE OF SHORT
WAVES MOVE IN THIS DIRECTION. BOTH OF THESE WAVES WILL MOVE JUST
SOUTH OF THE CWA BUT JET DYNAMICS WILL HELP TO PULL THE LIGHT SNOW
NORTHWARD. WE/LL SEE LIGHT SNOW DEVELOP BY 04Z SOUTH OF I-94 AND
THEN GRADUALLY SPREAD NORTHWARD TO NEAR I-96 AFTER MIDNIGHT. THIS
ISN`T AN IMPRESSIVE SYSTEM AND TOTAL SNOW SHOULD RANGE FROM AROUND
AN INCH NEAR I-96 TO PERHAPS AS HIGH AS 3 INCHES SOUTH OF I-94. SNOW
WILL END SUNDAY NIGHT AS THE SECOND WAVE MOVES EAST AND HIGH
PRESSURE WILL BUILD IN TO THE GREAT LAKES MONDAY.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EST SAT FEB 28 2015

WE CONTINUE TO EXPECT A MESSY SYSTEM TO COME THROUGH ON TUESDAY WITH
A POTENTIALLY HAZARDOUS MIXTURE OF SNOW...SLEET AND FREEZING RAIN.
THE PRECIPITATION SHOULD CHANGE OVER TO MAINLY RAIN FOR A TIME SOUTH
OF I-96 TUESDAY AFTERNOON AND EVENING.

WE HAVENT SEEN MUCH IMPACT FROM THE SOUTHERN STREAM OF THE JET THIS
WINTER IN MICHIGAN AND THAT LOOKS TO CHANGE VERY BRIEFLY EARLY NEXT
WEEK AS IT LIFTS NORTH IN RESPONSE TO A DEEP WEST COAST TROUGH. WIND
SPEEDS WITHIN THE UPPER JET ARE PROGGED TO BE 150 KTS OR MORE WITH
SOME POTENTIAL FOR A PERIOD OF COUPLED JET OR RIGHT ENTRANCE REGION
FORCING. THE LOW LEVEL JET IS PROGGED TO BE 50-70 KTS WHICH SENDS
PWATS OF AN INCH OR MORE NORTHWARD FROM THE GULF.

THIS LOOKS LIKE A RELATIVELY QUICK HITTING EVENT WITH MOST OF THE
PRECIP COMING IN A 12 HOUR PERIOD ON THE NOSE OF THE LOW LEVEL JET.
SUSPECT MUCH OF THIS PRECIP WILL BE CONVECTIVE IN NATURE SO HEAVY
PRECIP RATES ARE POSSIBLE BEFORE A DRY SLOT SWEEPS IN FROM THE
SOUTHWEST LATE TUESDAY/TUESDAY EVENING.

THE FREEZING RAIN/ICING POTENTIAL SHOULD BE HIGH GIVEN HOW COLD IT
HAS BEEN LATELY AND THAT ROADS/OBJECTS WILL REMAIN COLDER THAN THE
AIR TEMPS FOR THE INITIAL STAGES OF THE EVENT.

BASED ON THE LATEST THERMAL PROFILES IT LOOKS LIKE MOSTLY SNOW LATE
MONDAY NIGHT INTO EARLY TUESDAY MORNING FOLLOWED BY A QUICK CHANGE
TO FREEZING RAIN FOR AREAS NEAR/SOUTH OF I-96 15Z-21Z TUESDAY.
PRIMARILY SNOW EXPECTED NORTH OF I-96 THROUGH THE EVENT...POSSIBLY
MIXED WITH SOME SLEET/FREEZING RAIN. MAINLY RAIN SOUTH OF I-96
21Z-03Z. PRECIP GOES BACK TO ALL SNOW LATE TUESDAY NIGHT ALTHOUGH
MAINLY LIGHT WITH NO SIG ACCUMS EXPECTED.

AFTER THIS SYSTEM THE NORTHERN STREAM DOMINATES AGAIN FOR THE
REMAINDER OF THE WEEK SO MORE COLD AIR WITH OCCASIONAL LIGHT SNOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1251 PM EST SAT FEB 28 2015

QUIET WEATHER WILL START OFF THE FCST PERIOD FOR MOST OF THE AREA.
MOST AREAS WILL SEE ONLY A FEW HIGH CLOUDS INTO EARLY THIS
EVENING. THERE ARE SOME LAKE EFFECT CLOUDS AND LIGHT SNOW SHOWERS
AFFECTING THE KMKG AREA AND NORTH. SOME MVFR CIGS AND VSBYS WILL
BE POSSIBLE FOR THE NEXT COUPLE OF HOURS THERE.

CLOUDS WILL INCREASE THIS EVENING FROM SW TO NE. CIGS WILL START
OUT AROUND 8-10K FT. LIGHT SNOW WILL DEVELOP FROM SW TO NE
STARTING AROUND 03-05Z. THIS SNOW IS EXPECTED TO PRODUCE MAINLY
MVFR CONDITIONS WITH ITS LIGHT NATURE. SOME IFR WILL BE POSSIBLE
BRIEFLY AT TIMES...BUT MVFR WILL RULE. LIGHT SNOW WILL LIKELY MOVE
OUT VERY LATE TONIGHT INTO SUN MORNING...AND LEAVE LOW CLOUDS
BASED AROUND 2500 FT IN PLACE.

&&

.HYDROLOGY...
ISSUED AT 1132 AM EST SAT FEB 28 2015

CONDITIONS ON AREA RIVERS AND STREAMS REMAIN STABLE. THIS IS
EXPECTED TO CONTINUE TO BE THE CASE THROUGH AT LEAST THE NEXT
COUPLE OF DAYS.

THE PATTERN WILL BECOME MORE ACTIVE AS WE GET INTO
THE SECOND HALF OF THE WEEKEND AND INTO NEXT WEEK. THE EXTREME
COLD THAT HAS BEEN ALL TOO STUBBORN WILL BEGIN TO RELEASE ITS GRIP
ON THE REGION. AS A RESULT...GRADUALLY WARMER TEMPERATURES WILL
MAKE THEIR WAY IN THROUGH TUESDAY. WHILE THERE IS SOME QUESTION TO
THE EXTENT OF THE WARMTH IT IS STILL NOT ANTICIPATED TO CREATE
MANY ISSUES AS COLD AIR QUICKLY MOVES BACK IN DURING THE MIDDLE
OF THE WEEK. TOTAL PRECIPITATION AMOUNTS SHOULD HOVER AROUND A
HALF INCH THROUGH THE NEXT SEVEN DAYS WITH MOST OF THIS COMING
IN THE TUESDAY SYSTEM. RIVERS WILL BE MONITORED THROUGH THE NEXT
SEVERAL DAYS IN THAT CASE THAT ANY VARIABILITY IS SENSED.

&&

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

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...NJJ
HYDROLOGY...JAM