Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 281150
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
650 AM 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 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM EST SAT FEB 28 2015

VFR TODAY INTO THIS EVENING WITH THE EXCEPTION OF SOME MVFR CIGS
AROUND 2500 FT AT MKG THIS MORNING. LIGHT SNOW MOVING IN FROM THE
SOUTH AFTER 04Z TONIGHT WITH MVFR CIGS/VSBYS DEVELOPING. IFR VSBYS
UNDER 3 MILES MORE LIKELY LATE TONIGHT AT AZO/BTL/JXN THAN FARTHER
NORTH AT MKG/GRR/LAN.

&&

.HYDROLOGY...
ISSUED AT 1202 PM EST FRI FEB 27 2015

THE BATTLE CREEK SITE (BTCM4) ON THE KALAMAZOO RIVER HAS SHOWN
SOME ERRONEOUS DATA THROUGH THE MORNING HOURS. THIS HAS BEEN
DETERMINED TO BE CAUSED BY THE EXTREME COLD THAT SETTLED IN
OVERNIGHT. IT HAS SINCE SHOWN SIGNS OF RETURNING BACK TO ITS
ORIGINAL READING AS A RESULT OF THE SUNSHINE THIS AFTERNOON.
COORDINATION WITH LOCAL OFFICIALS HAS NOT REVEALED ANY NEED FOR
CONCERN.

WHILE AREA STREAMS AND RIVERS HAVE BEEN STABLE FOR SEVERAL WEEKS
NOW A RATHER ACTIVE PERIOD AND GRADUAL WARMING TREND IS EXPECTED.
THIS DOES NOT NECESSARILY RAISE ALARM BUT WE SHOULD HEED SPECIFICS
AS TEMPERATURES BEGIN TO INCREASE AND PRECIPITATION APPROACHES.
TOTAL PRECIPITATION THROUGH THE NEXT SEVEN DAYS IS ANTICIPATED TO
REMAIN UNDER AN INCH. THE REAL QUESTION COMES ON TUESDAY...AS TO
THE EXTENT OF WARMTH...PRECIPITATION AMOUNTS AND PRECIPITATION
TYPE. THAT SAID...WE WOULD NEED A MEANINGFUL AMOUNT OF MOISTURE
IN A SHORT PERIOD OF TIME...COUPLED WITH AN EXTENDED PERIOD OF
WARMTH TO CREATE INSTABILITY IN THE CURRENT ICE COVER. AS OF
NOW...NO REAL ISSUES ARE EXPECTED BUT RIVERS WILL BE MONITORED
THROUGH THE NEXT WEEK.

&&

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

$$

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






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