Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KGRR 162334
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
634 PM EST TUE DEC 16 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 331 PM EST TUE DEC 16 2014

RAIN CHANGES TO LIGHT SNOW SHOWERS TOWARD MIDNIGHT. MOSTLY LIGHT
SNOW SHOWERS WILL CONTINUE INTO THURSDAY MORNING. QUIET WEATHER
WILL RETURN LATER THURSDAY AND CONTINUE THROUGH THE WEEKEND.
TEMPERATURES WILL BE NEAR NORMAL THROUGH THIS PERIOD. ANOTHER
SIGNIFICANT PRECIPITATION EVENT IS EXPECTED EARLY NEXT WEEK. THAT
SHOULD BE RAIN CHANGING TO SNOW. COLDER WEATHER WILL FOLLOW THAT
SYSTEM.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 331 PM EST TUE DEC 16 2014

NOT MUCH HAS CHANGED IN OUR FORECAST OVER THE PAST FEW DAYS AND
MY CURRENT THINKING IS AS IT HAS BEEN FOR SEVERAL DAYS NOW. THE
COLD AIR COMES IN TONIGHT TRAILING A SECONDARY COLD FRONT. THIS
WILL CHANGE THE RAIN SHOWERS TO SNOW SHOWERS BY MIDNIGHT ACROSS
THE AREA. THE SNOW SHOWERS MAY END FOR A WHILE SOUTH OF MUSKEGON
(AFTER MIDNIGHT) BUT WILL RESUME BY MORNING AND CONTINUE INTO
THURSDAY MORNING. ACCUMULATIONS WILL BE LIGHT BUT I DO EXPECT 1 TO
3 INCHES TO FALL OVER THE 48 HOURS OF THIS EVENT.

WE HAVE A CLOSED COLD CORE UPPER LOW DROPPING SOUTHEAST THROUGH THE
AREA WITH 850 TEMPS NEAR -10C. THE SURFACE AIR COMING OFF SHORE
FROM WISCONSIN SHOULD HAVE TEMPERATURES IN THE MID TO UPPER 20S
TOMORROW SO THAT SHOULD BE COLD ENOUGH TO ALLOW ENOUGH SURFACE
INSTABILITY FOR SHALLOW CONVECTION NEEDED FOR LAKE EFFECT. THE NAM
DOES SHOW SOME LIMITED CAPE (30 TO 50 J/KG OF MOST UNSTABLE CAPE).
THE CLOUD TOPS DO REACH THE DGZ BUT JUST BARELY SO I DO EXPECT
ACCUMULATING SNOW FROM THIS EVENT. WINDS WILL BE WEST TO NORTHWEST
SO MOST AREAS WEST OF US-131 SHOULD SEE SOME SNOW. THIS ALL COMES
TO AN END BY THURSDAY AFTERNOON AS THAT SYSTEM MOVES OUT OF THE
AREA.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 331 PM EST TUE DEC 16 2014

CANADIAN HIGH PRESSURE SHOULD DOMINATE THE EARLY PORTION OF THE
EXTENDED FORECAST.  THIS STILL APPEARS TO KEEP A STORM SYSTEM OVER
THE GULF COAST STATES FROM REACHING OUR AREA.  WE MAY DRAG DOWN
ENOUGH COOL AIR FOR SOME LIGHT LAKE EFFECT SNOW AS THE GULF COAST
SYSTEM SLIDES UP THE EAST COAST LATE IN THE WEEKEND.  BUT WITH
SURFACE HIGH PRESSURE STILL NEARBY THESE WILL PROBABLY NOT END TO BE
MUCH MORE THAN JUST FLURRIES.

WE SHOULD BEGIN TO WARM ADVECTION SUNDAY NIGHT AS WE GET ON THE BACK
SIDE OF THE HIGH.  MAX TEMPS SHOULD INCH UP INTO THE 30S OR APPROACH
40 FOR MON/TUE.  GOOD AGREEMENT IN THE MODELS SHOWING A NORTHERN
STREAM SYSTEM DEVELOPING ACROSS THE PLAINS IN THIS TIME FRAME.  IT
APPEARS A COLD FRONT SHOULD ARRIVE TUESDAY OR TUESDAY NIGHT.  MIXED
PCPN COULD ARRIVE AS EARLY AS MONDAY AFTERNOON AND LINGER THROUGH
TUESDAY.  HOWEVER TEMP REGIMES SUGGEST ANY MIX SHOULD LARGELY TURN
TO JUST A COLD RAIN BY TUESDAY

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 634 PM EST TUE DEC 16 2014

IFR CONDITIONS WILL CONTINUE FOR MUCH OF THE EVENING AS SCATTERED RAIN
SHOWERS BEGIN MIX WITH WET SNOW. MVFR CONDITIONS WITH AREAS OF
IFR CAN BE EXPECTED LATER TONIGHT IN LIGHT SNOW. WINDS WILL BE
WEST AROUND 12 KNOTS WITH GUSTS OVER 20 KNOTS AT TIMES.

&&

.MARINE...
ISSUED AT 331 PM EST TUE DEC 16 2014

NORTHWEST WINDS TO 30 KNOTS WILL CONTINUE THROUGH MOST OF
WEDNESDAY SO I WILL CONTINUE THE SMALL CRAFT ADVISORY AS IS. WINDS
ARE JUST COMING AROUND TO THE NORTHWEST AS I WRITE THIS AND BY 7
PM I WOULD EXPECT TO SEE THE WINDS IN THE 20 TO 30 KNOT RANGE
ACROSS OUR NEAR SHORE AREA. THE STRONGEST WINDS WILL BE BETWEEN 7
PM TONIGHT AND 7 AM WEDNESDAY...THERE IS 30 TO 35 KNOTS IN THE
MIXED LAYER DURING THAT TIME. IT IS POSSIBLE SOME HIGHER GUSTS TO
GALE FORCE MAY OCCUR EARLY THIS EVENING AS THE COLD AIR STARTS TO
COME IN BUT IF IT DOES HAPPEN IT WILL BE BRIEF AND ISOLATED.


&&

.HYDROLOGY...
ISSUED AT 331 PM EST TUE DEC 16 2014

NO HYDRO IMPACTS EXPECTED OVER THE NEXT WEEK. 24 HOUR OBSERVED
RAINFALL TOTALS THROUGH TUESDAY MORNING WERE ALL LESS THAN A QUARTER
INCH. SMALL RISES CAN BE EXPECTED ON SMALLER RIVERS AND CREEKS...BUT
NOTHING MORE. ANY LIGHT PRECIP WILL CHANGE TO SNOW TONIGHT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR LMZ844>849.

&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...JK
AVIATION...OSTUNO
HYDROLOGY...EBW
MARINE...WDM




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.