Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 230030
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
730 PM EST THU JAN 22 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 321 PM EST THU JAN 22 2015

MOSTLY FAIR WEATHER WILL PREVAIL INTO SATURDAY. A CLIPPER WILL
BRING SOME SNOW FOR SUNDAY THEN IT WILL TURN COLDER ON MONDAY AND
TUESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 321 PM EST THU JAN 22 2015

ONLY REAL FORECAST CONCERN IN THE NEAR TERM IS FOR PRECIPITATION
TYPE LATE FRIDAY NIGHT AS MODEL SOUNDINGS SHOW THE DGZ IS NOT
SATURATED AFTER 06Z SATURDAY. KEPT THE PRECIP TYPE AS SNOW FOR
NOW BUT MAY HAVE TO ADD FREEZING DRIZZLE IF DGZ IS DRY IN FUTURE
RUNS DURING THE 06Z TO 12Z SATURDAY PERIOD. WITH THE SFC LOW
PASSING WELL NORTH OF THE FORECAST AREA...THE FORCING FOR ANY
PRECIP IS WEAK AND THERE DOES NOT APPEAR TO BE MUCH LIFT IN THE
STRATUS DECK...SO ANY PRECIP SHOULD BE LIGHT.

ONE OTHER POTENTIAL ISSUE IS FOR POPS LATE SATURDAY NIGHT. AT THIS
POINT IT APPEARS THAT BULK OF THE SNOW WITH THE APPROACHING
CLIPPER WILL HOLD OFF UNTIL AFTER 12Z SUNDAY. WENT WITH CHANCE
POPS FOR NOW WITH HIGHER CHANCES TO THE WEST. POPS WILL HAVE TO BE
RAISED FOR THE 06Z TO 12Z SUNDAY PERIOD IF A FASTER TREND DEVELOPS
AS WE GET CLOSER TO THE EVENT...AS HAPPENED WITH THE CLIPPER THAT
MOVED THROUGH YESTERDAY.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 321 PM EST THU JAN 22 2015

THE MAIN CONCERN DURING THE LONG TERM IS THE POTENTIAL FOR
ACCUMULATING SNOW SUNDAY. THE MODELS ARE PRETTY MUCH ON TRACK AND
CONVERGING ON A TRACK THAT TAKES A CLIPPER SOUTHEASTWARD ACROSS NW
INDIANA. THIS TRACK PLACES THE CWA ON THE COLD AND SNOWY SIDE. THE
LATEST ECMWF IS CLOSER TO ITS ENSEMBLE MEAN POSITION AND WILL
GENERALLY BE FOLLOWED.

ISENTROPIC LIFT WILL BEGIN EARLY SUNDAY AHEAD OF THE CLIPPER AND
CONTINUE THROUGH THE DAY. AS THE CLIPPER APPROACHES THE GREAT LAKES
A COLD FRONT WILL DROP SOUTH AND THE RESULTING BAROCLINIC ZONE WILL
BE CONDUCIVE FOR PCPN DEVELOPMENT. QPF AROUND A QUARTER INCH SHOULD
RESULT IN SNOWFALL ACCUMULATIONS IN THE 2-4 INCH RANGE GIVEN SNOW
RATIOS AROUND 14/15-1. THERE IS DEEP LIFT WITHING THE CLOUD LAYER
INCLUDING THE DGZ. HOWEVER...THE STRONGEST LIFT IS BELOW THE DGZ
WHICH MAY PRECLUDE THE SYSTEM FROM OVERPERFORMING. SNOWFALL WILL
WIND DOWN BY LATE AFTERNOON/EARLY EVENING SUNDAY.

HIGHS IN THE LOWER 30S ARE EXPECTED SUNDAY THEN COOLING TO AROUND 20
BY MONDAY BEHIND THE CLIPPER THEN BEGIN A WARMING TREND THROUGH THE
REST OF THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 728 PM EST THU JAN 22 2015

PLENTY OF MVFR CEILINGS IN PLACE ACROSS THE AREA AT 00Z...AND THE
THINKING IS THIS WILL CONTINUE THE REMAINDER OF THE NIGHT AND INTO
FRIDAY. THERE IS A CLEARING LINE JUST OFF TO THE NORTH AND WEST OF
THE AREA ACROSS CENTRAL LOWER AND CENTRAL LAKE MICHIGAN...BUT WE
ARE THINKING THIS WILL LIKELY LIFT BACK NORTHWARD AS THE FLOW
TURNS SOUTHWESTERLY. THE WIND WILL PICK AS WELL OUT OF THE
SOUTHWEST WHICH SHOULD KEEP THE CEILINGS IN PLACE. NOT EXPECTING
ANY PRECIP IN THE NEXT 24 HOURS AT THE TAF SITES. WINDS WILL
INCREASE AND BECOME GUSTY AROUND NOON ON FRIDAY WITH SOUTHWEST
WINDS OF 10-20 KNOTS WITH GUSTS TOWARDS 25 KNOTS AT TIMES.


&&

.HYDROLOGY...
ISSUED AT 321 PM EST THU JAN 22 2015

ALL GAUGES SHOW RIVER LEVELS BELOW BANKFULL. WILL CONTINUE
MONITORING FOR POTENTIAL ICE JAMS WHICH CAN CAUSE WATER LEVEL RISE
AT ANY TIME. SIGNIFICANT ICE JAM FLOODING IS UNLIKELY FOR THE TIME
BEING. A SMALL AMOUNT OF ICE MELT MAY OCCUR WITH MILDER TEMPERATURES
FRIDAY AND SATURDAY BEFORE COLDER AIR ARRIVES NEXT WEEK.

&&

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

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...DUKE
HYDROLOGY...CAS





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