Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 170830
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 AM EST WED DEC 17 2014

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

.SYNOPSIS...
ISSUED AT 330 AM EST WED DEC 17 2014

COLDER AIR AND GUSTY WINDS HAVE FOLLOWED A LOW THAT IS MOVING EAST
TOWARD THE ATLANTIC. LIGHT LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE
TODAY AND TONIGHT BUT ACCUMS WILL MAINLY BE LIMITED TO AROUND AN
INCH OR LESS...MAINLY WEST OF US-131. TEMPS WILL REMAIN IN THE LOWER
30S THROUGH SATURDAY BEFORE WARMING A BIT AS WE HEAD INTO NEXT WEEK.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EST WED DEC 17 2014

FORECAST CONCERNS DEAL WITH LAKE EFFECT SNOW CHANCES TODAY AND
TONIGHT.

WINDS HAVE BEEN GUSTY OVERNIGHT AS COLD AIR POURS INTO LOWER
MICHIGAN BEHIND THE DEPARTING LOW. LIGHT SYNOPTIC SNOW CONTINUES
MAINLY OVER NORTHERN LOWER ATTM AS THE UPPER LOW ROTATES INTO THE
STATE. MODELS CONTINUE TO SHOW H8 TEMPS NEAR -12C MOVING ACROSS THE
LAKE TODAY. THAT NORMALLY CREATES ENOUGH INSTABILITY FOR SHSN. THE
ISSUE TODAY THOUGH IS THE MEAGER DGZ. THE MODELS HAVE BEEN PRETTY
CONSISTENT SHOWING THE DGZ HUGGING THE TOP OF THE CLOUD LAYER AROUND
4K FT. IT DOESN/T LOOK TO ME THAT THE DGZ IS SUFFICIENTLY DEEP TO
PRODUCE DECENT SNOWFLAKES. WE/LL PROBABLY GET SOME BUT I/M
COMPLETELY UNDERWHELMED BY THIS SETUP. AS SUCH I/VE CUT BACK ON POPS
A BIT TODAY AND TONIGHT BUT STILL RETAINED THE HIGHEST VALUES WEST
OF US-131. THE BOUNDARY LAYER COLD AIR BAILS LATE THURSDAY AND SO
WHATEVER LAKE EFFECT SNOW IS STILL GOING SHOULD WIND DOWN TO
FLURRIES.

HIGHS DURING THE NEXT FEW DAYS WILL BE QUITE A BIT COLDER THAN WE/VE
SEE LATELY WITH LOWER 30S EXPECTED.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EST WED DEC 17 2014

BENIGN WEATHER WITH SLIGHTLY ABOVE NORMAL TEMPERATURE IS EXPECTED
THIS WEEKEND INTO EARLY NEXT WEEK AS A SFC RIDGE OF HIGH PRESSURE
DOMINATES OUR WEATHER. THE PATTERN TURNS MORE ACTIVE BY NEXT TUESDAY
AS A LONGWAVE TROUGH TAKES SHAPE OVER THE CENTER OF THE NATION. WARM
ADVECTION/ISENTROPIC LIFT AHEAD OF A DEVELOPING LOW OVER THE CENTRAL
PLAINS BRINGS A THREAT OF LIGHT MIXED RAIN AND SNOW MONDAY NIGHT
WHICH LOOKS TO CHANGE TO MOSTLY ALL RAIN ON TUESDAY AS GUIDANCE
SHOWS HIGHS NEAR 40.

LOOKING FARTHER AHEAD.. PRESENT INDICATIONS ARE FOR A LOW TO LIFT
NORTH FROM THE GULF COAST ON TUESDAY NIGHT AND WEDNESDAY... THEN
DEEPEN AND OCCLUDE OVER THE GREAT LAKES REGION ON CHRISTMAS EVE. THE
00Z ECMWF SOLUTION OF A 965 LOW OVER THE THUMB BY CHRISTMAS MORNING
SUPPORTS QUITE A BIT OF WIND WITH RAIN CHANGING TO SNOW. HOWEVER
THIS POTENTIAL SYSTEM IS STILL A WEEK OUT IN TIME SO CONFIDENCE ON
THE SPECIFICS IS LOW AND WE WILL LIKELY SEE VARYING SOLUTIONS OVER
TIME.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM EST TUE DEC 16 2014

EXPECT MOSTLY MVFR CONDITIONS WITH SOME AREAS OF IFR TONIGHT AND
INTO WEDNESDAY MORNING IN LIGHT SNOW SHOWERS. WINDS WILL BE
WESTERLY AROUND 12 KNOTS WITH GUSTS TO 20 KNOTS.


&&

.MARINE...
ISSUED AT 330 AM EST WED DEC 17 2014

NO CHANGES TO THE SCA. GUSTY NW WINDS WILL CONTINUE INTO THURSDAY
RESULTING
IN 5 TO 10 FT WAVES.

&&

.HYDROLOGY...
ISSUED AT 330 AM EST WED DEC 17 2014

NO HYDRO ISSUES.

&&

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

&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...MEADE
AVIATION...OSTUNO
HYDROLOGY...93
MARINE...93









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