Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 282028
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
328 PM EST WED JAN 28 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 328 PM EST WED JAN 28 2015

ROADS COULD BE ICY ON THURSDAY MORNING AS LOW PRESSURE BRINGS A
WINTRY MIX OF PRECIPITATION LATE TONIGHT. TEMPERATURES SHOULD RISE
ABOVE FREEZING BY LATE MORNING AND CONDITIONS SHOULD IMPROVE. SOME
LIGHT SNOW IS EXPECTED DURING THE AFTERNOON WITH ACCUMULATIONS AN
INCH OR LESS. IT WILL TURN MUCH COLDER ON FRIDAY AND INTO THE
WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 328 PM EST WED JAN 28 2015

KEPT THE HEADLINES AS IS. MAIN THREAT APPEARS TO BE LIGHT FREEZING
RAIN LATE TONIGHT WHICH WILL CAUSE ICY ROADS FOR THE THURSDAY
MORNING COMMUTE. WARM AIR ADVECTION IS ALREADY UNDERWAY AND
STRENGTHENS OVERNIGHT. AS THE VERY WARM AIR ACROSS THE PLAINS
ADVECTS EAST WE WILL SEE 850 MB TEMPS GO ABOVE 0C FOR BY 06Z FOR
ALL BUT THE FAR NORTHERN TIER. WE START OFF VERY DRY SO TEMPS WILL
DROP AS THE COLUMN SATURATES AND WE COULD SEE A QUICK BURST OF
SNOW AT THE ONSET BEFORE PRECIP GOES OVER TO IP AND FZRA. DO NOT
EXPECT MUCH QPF SO ICE AMOUNTS WILL BE LIMITED...BUT ENOUGH TO
CAUSE POTENTIAL TRAVEL PROBLEMS BEGINNING AFTER MIDNIGHT AND
CONTINUING THROUGH THE MORNING COMMUTE.

SOUTHERLY FLOW THROUGH THE MORNING SUGGESTS THAT SFC TEMPS SHOULD
WARM AS ANY FREEZING PRECIP BRINGS LATENT HEAT EFFECTS THAT ARE NOT
BEING OFFSET BY CAA NEAR THE SFC. SO EXPECT ICING ISSUES TO END
DURING THE MORNING. SFC LOW MOVES EAST AND COLD AIR ADVECTION ON
NORTHWEST FLOW BEGINS AFTER 18Z WITH PRECIP TRANSITIONING BACK TO
SNOW FROM NORTH TO SOUTH. SNOW ACCUMULATIONS AN INCH OR LESS AND
TEMPERATURES SHOULD NOT BE COLD ENOUGH TO ALLOW MUCH ACCUMULATION ON
ROADS...SO IMPACTS ARE EXPECTED TO BE MINOR.

SYNOPTIC SNOWS END BY EVENING WITH SOME NORTH TO NORTHWEST LAKE
EFFECT. INVERSION HEIGHTS ARE AOB 5KFT DURING THE EVENING SO LAKE
EFFECT SHOULD NOT BE HEAVY.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 328 PM EST WED JAN 28 2015

OVERALL MODELS ARE TRENDING FURTHER SOUTH WITH THE TRACK OF THE LOW
SATURDAY NIGHT THROUGH SUNDAY...SUGGESTING LOWER MICHIGAN WILL END
UP WITH LESS PRECIPITATION AND COLDER TEMPERATURES.  HIGH RES EURO
SUGGESTS A DRY FORECAST IS THE WAY TO GO FOR SUNDAY.  NOT READY TO
DROP POPS COMPLETELY...BUT THE PATTERN WE ARE IN HAS BEEN A DRY
ONE.  AS A RESULT I WILL LOWER POPS ON SUNDAY AND BACK OFF ON THE
QPF CONSIDERABLY.

LOOKING FURTHER AHEAD...STRONGER WARM AIR ADVECTION IS NOTED FOR
TUESDAY.  WITH AN ARCTIC AIRMASS IN PLACE...THAT SHOULD SUPPORT A
SOUTHWEST FLOW EVENT. POPS WERE INCREASED...ESPECIALLY WEST OF GRAND
RAPIDS.

I DID LOWER TEMPERATURES ESPECIALLY SUNDAY NIGHT AND MONDAY GIVEN
THE DOMINANCE OF THE ARCTIC AIR.  THE MODELS COMMONLY ARE TOO WARM
WITH THE NIGHTTIME LOWS DURING THESE EVENTS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1247 PM EST WED JAN 28 2015

CONFIDENCE INCREASING ON IMPACT CONDITIONS AT THE TAF SITES LATER
TONIGHT THROUGH THU MORNING. FREEZING RAIN...SLEET AND SNOW WILL
WORK ITS WAY IN FROM THE SOUTHWEST AND PERSIST THROUGH THU
MORNING. AHEAD OF IT THERE COULD BE WIND SHEAR AS LOW LEVEL WINDS
BACK TO THE SOUTHEAST AS A STRONGER LOW LEVEL JET ARRIVES FROM THE SOUTH.

IFR CONDITIONS MAY BE DELAYED INITIALLY DUE TO THE DRY
AIR...HOWEVER ONCE THEY ARRIVE LATER TONIGHT...THEY SHOULD PERSIST
THROUGH THE MORNING.

THE WIND WILL SHIFT SHARPLY THURSDAY MORNING AS THE WAVE OF LOW
PRESSURE TRACKS THROUGH.

&&

.HYDROLOGY...
ISSUED AT 328 PM EST WED JAN 28 2015

COLD WEATHER WITH ONLY LIGHT PRECIPITATION SHOULD MEAN NO
SIGNIFICANT TRENDS IN THE RIVERS. ICE WILL FORM OVER THE WEEKEND
AS THE COLD INTENSIFIES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 1 AM TO 4 PM EST THURSDAY FOR
     MIZ037-043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...MJS
AVIATION...MJS
HYDROLOGY...OSTUNO




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