Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 222336
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
636 PM EST MON DEC 22 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 PM EST MON DEC 22 2014

WIDESPREAD RAIN CAN BE EXPECTED TONIGHT AND TUESDAY MORNING AS A
WARM FRONT LIFTS NORTH TOWARD THE SOUTHERN GREAT LAKES REGION. THE
PRECIPITATION WILL INITIALLY BE A MIXTURE OF SNOW... SLEET AND
FREEZING RAIN TONIGHT NEAR AND NORTH OF HIGHWAY U.S. 10.

RAIN WILL TAPER OFF FROM SOUTH TO NORTH TUESDAY AFTERNOON... BUT
MORE RAIN WILL ARRIVE FROM THE SOUTH FOR LATE TUESDAY NIGHT AND
WEDNESDAY. THE RAIN WILL CHANGE TO WET SNOW ON CHRISTMAS EVE WITH A
FEW INCHES OF ACCUMULATION POSSIBLE BEFORE ENDING BY CHRISTMAS
MORNING.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 330 PM EST MON DEC 22 2014

A WINTER WEATHER ADVISORY WILL BE IN EFFECT TONIGHT FOR CLARE...
OSCEOLA... AND LAKE COUNTIES FOR A PERIOD OF MIXED SNOW... SLEET...
AND FREEZING RAIN. THE MAIN THREAT IS FROM 7 PM TO 4 AM BUT WILL RUN
IT UNTIL 7 AM IN CASE THE MIX LINGERS A BIT LONGER THAT ANTICIPATED.
NO SIGNIFICANT AMOUNTS OF SNOW OR FREEZING RAIN ARE EXPECTED HOWEVER
THERE SHOULD BE ENOUGH TO SLICKEN THE ROADWAYS.

RAIN IS RACING IN RAPIDLY FROM THE SOUTHWEST WITH TEMPERATURES
MOSTLY IN THE MID TO UPPER 30S. HOWEVER THE SFC DEW POINTS ARE ONLY
IN THE MID 20S NORTH OF I-96. EVAPORATIVE COOLING AS THE RAIN FALLS
INTO THE DRIER AIR SHOULD LEAD TO TO A MIX OF PRECIP TYPES ACROSS
THE TYPICALLY COLDER INTERIOR OF CENTRAL AND NRN LWR MI. THIS IS
RELATIVELY SHORT LIVED HOWEVER AS STRONG WARMING TAKES PLACE AFTER
06Z. BELIEVE IT WILL BE WARM ENOUGH FOR ALL RAIN ACROSS THE ADVISORY
AREA BY 4-5 AM AND IF SO THE HEADLINE COULD BE CANCELLED EARLY.

SNOW ACCUMULATIONS FOR THE CHRISTMAS EVE EVENT CONTINUE TO LOOK
LIMITED DUE TO LACK OF GOOD COLD AIR. A PERIOD OF DEFORMATION ZONE
SNOW DOES APPEAR LIKELY BUT AT THIS TIME ACCUMULATIONS ONLY LOOK TO
BE ABOUT 1-3 INCHES. THE LATEST TREND OF THE 12Z GFS/ECMWF IS A TAD
FARTHER WEST WITH THE SFC LOW TRACK. THAT IMPLIES A WARMER SOLUTION
WITH THE CHANGE TO SNOW A BIT DELAYED AND OCCURRING AS HEAVIEST
PRECIP IS EXITING.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 330 PM EST MON DEC 22 2014

WE/LL BE IN BETWEEN SYSTEMS AS THE LONG TERM BEGINS THURSDAY. RIDGING
WILL REPLACE THE DEPARTING LOW AND MUCH OF THE CWA WILL BE DRY
THURSDAY/THURSDAY NIGHT. WARMER AIR WILL MOVE BACK INTO THE CWA
THURSDAY NIGHT AND FRIDAY.

FRIDAY NIGHT INTO SATURDAY NIGHT WILL BE AN OPPORTUNITY FOR MORE
PCPN AS AN UPPER TROUGH MOVES TOWARD THE GREAT LAKES. A SFC LOW
DRAGGING SOME MOISTURE NORTHWARD SHOULD PRODUCE MIXED RAIN AND SNOW
FRIDAY NIGHT AND SOME LIGHT LAKE EFFECT SNOW SHOWERS SATURDAY AND
SATURDAY NIGHT. THE ECMWF SHOWS A SOUTHERN STREAM SYSTEM MOVING
ACROSS THE NORTHERN TENNESSEE VALLEY JUST CLIPPING THE CWA WITH
LIGHT SNOW SUNDAY.

OVERALL CONFIDENCE IS NOT REAL HIGH WITH RESPECT TO PCPN TIMING NOR
AMOUNTS AS SIGNIFICANT SFC SYSTEMS ARE PROGD TO MAINLY MISS THE CWA.
TEMPS WILL VARY FROM THE LOWER 40S FRIDAY TO LOWER 30S
MONDAY/TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 632 PM EST MON DEC 22 2014

TRENDS SUPPORT A DELAY IN THE ARRIVAL OF THE IFR TONIGHT. THE
SOUTHEAST FLOW WAS CAUSING CEILINGS TO END UP HIGHER THAN
FORECASTED. WITH A WARM FRONT LIFTING UP FROM THE SOUTH
TONIGHT...THE CEILINGS AND VISIBILITIES WILL LIKELY END UP IN THE
IFR RANGE...GENERALLY AFTER 06Z. THE LOW CONDITIONS WILL THEN
LINGER THROUGH TUESDAY MORNING. SOME IMPROVEMENT IS POSSIBLE FOR
THE AFTERNOON.

WITH WARMER AIR MOVING IN...THE SLEET AND FREEZING RAIN POTENTIAL
IS SHIFTING NORTH WITH TIME. FOR NOW I STILL HAVE A POTENTIAL
MIXTURE OF PRECIPITATION ONLY FOR KJXN AND KLAN FOR AN HOUR OR TWO.

&&

.MARINE...
ISSUED AT 330 PM EST MON DEC 22 2014

WINDS WILL BE OFFSHORE TONIGHT SO WILL CANCEL THE SMALL CRAFT
ADVISORY EARLY. A PERIOD OF STRONG WINDS/WAVES APPEARS LIKELY ON
CHRISTMAS EVE.


&&

.HYDROLOGY...
ISSUED AT 330 PM EST MON DEC 22 2014

THROUGH CHRISTMAS EVE...AN INCH OR MORE OF WIDESPREAD RAINFALL IS
POSSIBLE. THE HEAVIEST AMOUNTS ARE ANTICIPATED TO BE ACROSS THE
EASTERN GRAND AND KALAMAZOO/ST JOE RIVER BASINS. THIS WILL CERTAINLY
CAUSE RISES ON AREA RIVERS AND STREAMS. 72 HOUR ENSEMBLE QPF
SIMULATIONS ARE SHOWING THE BIGGEST RISES FOR THE EASTERN PORTION OF
THESE BASINS. SOME SITES COULD APPROACH BANKFULL WITH THIS RAINFALL
IF OVER AN INCH MATERIALIZES (CERTAINLY IF 1.5-2.0 INCHES WERE TO
FALL). AT THIS POINT THERE IS NOT A SIGNIFICANT THREAT FOR ANY MINOR
FLOODING. SO...WOULD EXPECT THE MAIN IMPACT WOULD BE HIGHER THAN
NORMAL FLOWS HEADING INTO THE END OF DECEMBER.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ038>040.

LM...NONE.
&&

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...93
AVIATION...MJS
HYDROLOGY...HOVING
MARINE...MEADE






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