Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 241745
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1245 PM EST MON NOV 24 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EST MON NOV 24 2014

RAIN ONGOING EARLY THIS MORNING WILL DIMINISH A BIT IN COVERAGE
AND INTENSITY THIS MORNING. INTERVALS OF RAIN WILL CONTINUE
THROUGH MID AFTERNOON ACROSS THE AREA BEFORE ALL RAIN CHANGES TO
SNOW FAIRLY RAPIDLY LATE THIS AFTERNOON INTO EARLY THIS EVENING.
SNOW WILL ACCUMULATE ACROSS THE AREA FROM TONIGHT THROUGH
TUESDAY...WITH THE HIGHEST AMOUNTS OCCURRING TO THE NORTHWEST
TOWARD LUDINGTON.

WE WILL SEE A BREAK IN THE SNOW FROM LATE TUESDAY NIGHT INTO
WEDNESDAY BEFORE SNOW SHOWERS WILL BECOME POSSIBLE ONCE AGAIN.
THERE WILL BE AT LEAST A CHANCE OF SNOW FOR THANKSGIVING AND INTO
THE WEEKEND...HOWEVER NO SIGNIFICANT SNOWFALL IS EXPECTED LATER
THIS WEEK. A MODERATION IN TEMPERATURES AND PRECIPITATION CHANGING
OVER TO RAIN WILL BE POSSIBLE NEXT WEEKEND.

&&

.UPDATE...
ISSUED AT 1149 AM EST MON NOV 24 2014

NO CHANGES WITH THE MORNING UPDATE AS THE GOING FORECAST LOOKS TO
HAVE THINGS WELL IN HAND. STRONG WIND GUSTS ARE ABOUT TO SURGE
INTO THE SOUTHERN FORECAST AREA ALONG INTERSTATE 94 FROM THE
SOUTH. GUSTS AROUND 45 MPH APPEAR LIKELY ACROSS ABOUT THE SOUTHERN
HALF OF THE GRR FORECAST AREA OR ROUGHLY SOUTH OF A MUSKEGON TO
ALMA LINE. CANNOT RULE OUT A FEW GUSTS INTO THE 50-55 MPH RANGE
FROM BATTLE CREEK TO LANSING AND JACKSON THIS AFTERNOON AND EVENING.

REGARDING SNOW WILL BE LEAVING THE FORECAST AMOUNTS ALONE AS THEY
SEEM TO BE IN LINE WITH SOME OF THE LATEST GUIDANCE COMING IN.
WILL LOOK AT THIS CLOSER THROUGH THE AFTERNOON THOUGH. STILL
LOOKING LIKE WE SEE A CHANGE OVER FROM RAIN TO SNOW IN THE 21Z-00Z
TIME FRAME...BECOMING ALL SNOW PRETTY QUICKLY AFTER 00Z/7PM. A
BAND OF HEAVY SNOW LOOKS LIKELY ACROSS PORTIONS OF CENTRAL LOWER
MICHIGAN...ESPECIALLY OVER ABOUT OUR NORTHWEST QUARTER OF THE CWA.
THAT HEAVY SNOW OCCURS THIS EVENING INTO TONIGHT AS THE
DEFORMATION ZONE SETS UP THERE.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 330 AM EST MON NOV 24 2014

WE HAVE ISSUED A WIND ADVISORY FOR THIS AFTERNOON AND EARLY
EVENING FOR ROUGHLY THE SE HALF OF THE FCST AREA. A WINTER WEATHER
ADVISORY HAS BEEN ISSUED FOR ROUGHLY THE NW HALF OF THE AREA FOR
LATE THIS AFTERNOON THROUGH THE DAY ON TUESDAY.

STEADY RAIN CONTINUES TO FALL ACROSS THE AREA EARLY THIS MORNING
WITH THE DRY SLOT TRYING TO MAKE IT INTO THE FCST AREA FROM THE
SOUTH. WE ARE SEEING THE MODERATE RAIN THAT FELL LAST EVENING SHIFT
OUT OF THE AREA AS THE CORE OF THE LLJ AHEAD OF THE LOW SHIFTS EAST
OF THE AREA. THE DRY SLOT SHOULD STAY JUST SOUTH OF THE CWFA
BORDER...KEEPING PERIODS OF RAIN/SHOWERS MOVING THROUGH THE AREA
TODAY. THE AREA OF SHOWERS MOVING ACROSS SRN IL AS OF 08Z THIS
MORNING WILL BE THE LAST OF THE WIDESPREAD RAIN FOR THE AREA THAT
WILL MOVE THROUGH LATE THIS MORNING AND INTO THE AFTERNOON HOURS.

THE WINDS ARE LIGHT RIGHT NOW ACROSS THE AREA...BUT WILL INCREASE
LATE THIS MORNING/EARLY THIS AFTERNOON ACROSS THE SE PORTION OF THE
CWFA. THE BAND OF SHOWERS ACROSS SRN IL IS WITH A SFC WAVE THAT WILL
MOVE UP INTO THE AREA. ONCE THIS WAVE MOVES BY...THE COLD AIR
ADVECTION WILL COMMENCE AS THE STRONGER GRADIENT MOVES IN. MODELS
INDICATE THAT 40 KNOTS OR SO AROUND 2K FT WILL BE VERY ABLE TO BE
MIXED DOWN WITH THE GOOD MIXING DUE TO THE COLD AIR ADVECTION.

WE WILL SEE ALL RAIN CHANGE OVER TO SNOW FAIRLY QUICKLY FROM SW TO
NE AFTER 21Z AND ALMOST ACROSS THE ENTIRE AREA TOWARD 00Z. WE WILL
SEE THE BAND OF PCPN COMING UP AHEAD OF THE SRN IL WAVE MOVE NORTH
AND ALMOST BECOME STATIONARY ACROSS THE NW HALF OF THE CWFA. THIS
OCCURS INITIALLY WITH AN INITIAL DEFORMATION BAND FROM THE UPPER
WAVE COMING IN FROM THE SW. WE WILL THEN SEE THE NEXT SHORT WAVE
WITH THE PARENT TROUGH ROTATE IN ACROSS THE AREA AND FAVOR THE NW
COUNTIES ONCE AGAIN. BY THIS TIME...IT WILL BE SNOWING AND WILL
ACCUMULATE.

THIS SNOW WILL AFFECT THE NW HALF OF THE CWFA FROM THIS EVENING INTO
EARLY TUE AFTERNOON WHEN A THIRD SHORT WAVE MOVES THROUGH IN THE
SAME FASHION. WE ARE LOOKING AT A PROLONGED LIGHT SNOW EVENT WITH
SOME ENHANCEMENT AT TIMES DUE TO A SW FLOW OFF OF THE LAKE. DELTA
T/S WILL BE IN THE TEENS AND MOISTURE WILL BE QUITE DEEP OVER THE
AREA. WHAT WILL KEEP THIS FROM BEING A MORE SIGNIFICANT EVENT WILL
BE AN INVERSION THAT FLUCTUATES FROM 5-8K FT. THIS WILL LIMIT THE
LAKE ENHANCEMENT FROM BECOMING TOO STRONG...BUT SOME LOCALLY HEAVIER
AMOUNTS WILL STILL BE POSSIBLE. SOME UPSLOPE FLOW ACROSS THE HILLS
OF CENTRAL LOWER COULD ALSO HELP TOTALS A BIT. SOME BLOWING AND
DRIFTING WILL BE POSSIBLE TOWARD THE LAKESHORE WHERE WINDS WILL BE A
LITTLE STRONGER.

AS THE MAIN UPPER TROUGH FINALLY PULLS OUT TUE AFTERNOON...WE WILL
SEE SNOW SHOWERS DIMINISH. THERE COULD BE SOME DECENT BANDS MOVE
THROUGH GRR TUE MORNING AS THE FLOW BECOMES MORE WNW BEFORE
EVERYTHING ENDS LATE TUE. AMOUNTS WILL BE LOWER TOWARD GRR...HOWEVER
THE TUE MORNING COMMUTE COULD BE IMPACTED.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 330 AM EST MON NOV 24 2014

OTHER THAN THE POSSIBILITY OF SOME LIGHT LAKE EFFECT SNOW
ACCUMULATIONS ON THANKSGIVING DAY... CONFIDENCE IS INCREASING THAT
MINIMAL TRAVEL IMPACTS WILL OCCUR OVER THE UPCOMING HOLIDAY PERIOD.

MODELS HAVE TRENDED MUCH FARTHER SOUTH WILL THE CLIPPER LOW ON
WEDNESDAY AND WEDNESDAY NIGHT SO THE SYNOPTIC SNOW POTENTIAL WITH
THAT SYSTEM NOW LOOKS QUITE LOW.

H8 AIR AROUND -15C IS STILL PROGGED TO COME INTO THE AREA VIA
NORTHWEST WINDS ON THANKSGIVING DAY. CONDITIONS LOOK FAVORABLE FOR
LAKE EFFECT SNOW FOR ABOUT 12 HOURS AS H5 SHORTWAVE PIVOTS
THROUGH... SO A FEW INCHES OF ACCUMULATION STILL APPEARS POSSIBLE
NEAR AND WEST AND HIGHWAY 131. SURFACE RIDGING AND WARM ADVECTION
ARRIVES THURSDAY NIGHT AND THE LAKE EFFECT SHOULD DIMINISH AT THAT
TIME.

AFTER THANKSGIVING DAY... THE UPPER FLOW GOES FLAT/ZONAL WITH 100 KT
PACIFIC JET SHOOTING ACROSS THE NRN CONUS. THIS PATTERN WILL LEAD TO
MILDER TEMPERATURES DEVELOPING ACROSS SW MI TOWARD THE END OF THE
WEEK WITH ONLY A SMALL CHANCE FOR LIGHT SNOW OR MIXED LIGHT RAIN AND
SNOW.

LATEST 00Z GUIDANCE NOW SHOWS A RATHER STRONG WARM ADVECTION PATTERN
ON SATURDAY AHEAD OF A NRN PLAINS LOW... SO WE MAY NEED TO BOOST
HIGHS INTO THE 40S IF THIS TREND REMAINS. THAT SAME SYSTEM DRAGS A
COLD FRONT THROUGH ON SATURDAY NIGHT OR EARLY SUNDAY AS IT MOVES
EAST... BUT NOT MUCH QPF ALONG THE FRONT AND STRONG SURFACE RIDGING
DEVELOPING BEHIND IT ON SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1242 PM EST MON NOV 24 2014

WINDS WILL INCREASE TO 40KTS AT TIMES THIS AFTERNOON FROM THE WSW
AND WON/T DIMINISH UNTIL MID EVENING. SHRA WILL TRANSITION TO SHSN
THIS AFTERNOON AS COLDER AIR WORKS INTO LOWER MICHGIAN. VSBYS WILL
REMAIN BLO 5SM THROUGH MUCH OF THE PERIOD EXCEPT AT KLAN/KJXN.

&&

.MARINE...
ISSUED AT 430 AM EST MON NOV 24 2014

A SIGNIFICANT INCREASE IN WINDS FROM THE WEST SOUTHWEST IS
ANTICIPATED TODAY AS A DEEPENING LOW PRESSURE SYSTEM MOVES
NORTHEAST THROUGH THE GREAT LAKES REGION. GALES WILL DEVELOP SOUTH
OF PENTWATER LATER THIS MORNING AND CONTINUE THROUGH THIS EVENING
BEFORE GRADUALLY DIMINISHING LATE TONIGHT AS THE LOW PULLS AWAY.
WAVES WILL BUILD TO AS HIGH AS 12 FEET DURING THE PEAK OF THE
EVENT LATER TODAY.


&&

.HYDROLOGY...
ISSUED AT 430 AM EST MON NOV 24 2014

WIDESPREAD RAINFALL AMOUNTS OF 1.00 TO 1.50 HAVE ALREADY OCCURRED
AND UP TO ANOTHER 0.50 IS STILL POSSIBLE TODAY. MANY OF THE SMALLER
TRIBUTARIES SUCH AS THE MACATAWA RIVER AT ZEELAND AND PLASTER CREEK
IN GRAND RAPIDS HAVE SHOWN SIGNIFICANT RISES OVERNIGHT DUE TO THE
RAIN... SUGGESTING SOME IMPACTS ARE POSSIBLE THIS MORNING WITH
WATER OVER ROADS/PARKING LOTS IN SPOTS. PLENTY OF STANDING WATER
WILL BE NOTICEABLE AS WELL TODAY IN ANY LOW LYING OR POOR DRAINAGE
AREAS.

ON THE LARGER RIVERS/TRIBUTARIES... RIVER FLOOD ADVISORIES HAVE
BEEN ISSUED FOR EXPECTED BANKFULL STAGES AT THE FOLLOWING
LOCATIONS: THE LOOKING GLASS RIVER AT EAGLE... SYCAMORE CREEK AT
HOLT... THE FLAT RIVER AT SMYRNA... AND THE ROGUE RIVER AT
ROCKFORD.

BASED ON THE RAINFALL THAT HAS ALREADY FALLEN... ADDITIONAL RIVER
ADVISORIES FOR BANKFULL STAGES WILL LIKELY BE NEEDED LATER THIS
MORNING FOR AT LEAST THE FOLLOWING LOCATIONS: THE PERE MARQUETTE AT
SCOTTVILLE... THE WHITE RIVER AT WHITEHALL... AND MAPLE RIVER AT
MAPLE RAPIDS... THE THORNAPPLE AT HASTINGS... AND THE GRAND RIVER AT
IONIA. THE RESPONSE AT THESE LOCATIONS IS MORE DELAYED THAN THE
ABOVE LOCATIONS... WITH BANKFULL STAGES PROBABLY NOT OCCURRING
UNTIL 1-3 DAYS FROM NOW.

NO RIVERS ARE EXPECTED TO REACH THEIR FLOOD STAGES AT THIS
POINT... BUT THIS WILL NEED TO BE CLOSELY MONITORED OVER THE NEXT
24 HOURS AS RAINFALL HAS BEEN A LITTLE MORE THAN EXPECTED WITH A
BIT MORE TO COME... AND ALL THE SNOW PACK HAS MELTED.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MIZ052-058-059-
     064>067-071>074.

     WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM EST
     TUESDAY FOR MIZ037>040-043>046-050-051-056-057.

LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LMZ849.

     GALE WARNING UNTIL 7 AM EST TUESDAY FOR LMZ844>848.

&&

$$

UPDATE...DUKE
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...93
HYDROLOGY...MEADE
MARINE...MEADE





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