Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 252334
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
634 PM EST TUE NOV 25 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 320 PM EST TUE NOV 25 2014

WE WILL SEE A BREAK IN WINTER PRECIPITATION THROUGH WEDNESDAY. THE
NEXT UPPER DISTURBANCE WILL BRING ANOTHER ROUND OF ACCUMULATING LAKE
EFFECT SNOW MAINLY NEAR THE LAKESHORE FROM WEDNESDAY NIGHT THROUGH
THANKSGIVING. THEN...A MIX OF RAIN...SNOW....AND SLEET IS EXPECTED
FROM FRIDAY THROUGH THE WEEKEND. TEMPERATURES WILL GENERALLY BE NEAR
NORMAL THROUGH THE PERIOD.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 320 PM EST TUE NOV 25 2014

MAIN CONCERN IS LAKE EFFECT SNOW WEDNESDAY NIGHT THROUGH
THANKSGIVING. ALTHOUGH WE ONLY ADVERTISE ABOUT 3 INCH TOTALS NEAR
THE LAKESHORE DURING THIS PERIOD THERE IS SOME POTENTIAL FOR THIS
EVENT TO OVER-PERFORM GIVEN AGREEMENT BETWEEN THE NAM/GFS FORECAST
SOUNDINGS FOR THERE TO BE A DEEP SATURATED MIXED LAYER THROUGH THE
DGZ UP TO AROUND 10000 FT. THERE ARE TWO OFFSETTING FACTORS
HOWEVER. 1) FAIRLY WARM DAYTIME TEMPERATURES ON THANKSGIVING THAT
MAY LIMIT ACCUMULATIONS. 2) DIRECTIONAL SHEAR IN THE FORECAST
SOUNDINGS COMBINED WITH NON-LAMINAR FLOW DURING DAYTIME HEATING THAT
WILL LIKELY PREVENT PERSISTENT SNOW BANDS FROM OCCURRING AND
CONCENTRATING SNOWFALL.

NONETHELESS...BRIEFLY INTENSE SNOWFALL RATES AND RESTRICTIONS TO
VISIBILITY ARE NOT OUT OF THE QUESTION ESPECIALLY NEAR THE LAKESHORE
AND COULD STILL IMPACT THANKSGIVING TRAVEL. SNOW SHOULD SHUT OFF
RATHER QUICKLY THURSDAY NIGHT AS LOW LEVEL FLOW BECOMES ANTICYCLONIC
WITH A SHARP SURFACE PRESSURE RIDGE MOVING INTO THE AREA.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 320 PM EST TUE NOV 25 2014

WIDE TEMPERATURE VARIABILITY IS EXPECTED DURING THE LONG TERM. A
GENERAL ZONAL UPPER FLOW PATTERN WILL DEVELOP LATER THIS WEEK AND
PERSIST INTO NEXT WEEK. SEVERAL SYSTEMS WILL MOVE ACROSS MICHIGAN
PRODUCING A MIX OF RAIN AND SNOW.

FRIDAY WILL START OFF WITH TEMPS WELL BELOW NORMAL AND WE MAY SEE
SOME LIGHT SNOW AS A WARM FRONT APPROACHES FROM THE SOUTHWEST.
STRONG ISENTROPIC LIFT DEVELOP FRIDAY MORNING AND THEN MOVES NEWD.
SNOW CHANCES WILL DIMINISH FRIDAY NIGHT AS WARMER AIR MOVES IN.
SATURDAY LOOKS MAINLY DRY. A CLIPPER IS THEN PROGD TO MOVE ACROSS
SOUTHERN CANADA DRAGGING A COLD FRONT THROUGH MICHIGAN SUNDAY. THIS
MAY PRODUCE LIGHT RAIN OR MIXED LIGHT RAIN/SNOW BUT MUCH OF THE
MOISTURE WILL REMAIN NORTH OF THE CWA NEAR THE LOW. COLDER TEMPS ARE
THEN EXPECTED SUNDAY NIGHT AND MONDAY BEFORE WARMER AIR MOVES IN
TUESDAY ON THE BACK SIDE OF THE HIGH. ANOTHER SHOT OF WARMER AIR
TUESDAY MAY RESULT IN LIGHT RAIN WITH HIGHS AROUND 40.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 629 PM EST TUE NOV 25 2014

THE STRATOCUMULUS ISN`T GOING ANYWHERE FOR THIS SET OF TAFS.
LITTLE CHANGE IN CIGS IS EXPECTED. WINDS MAY GO CALM BETWEEN 06Z-
12Z BEFORE A LIGHT SE WIND (OR JUST LIGHT AND VARIABLE) DEVELOPS.
NO PRECIPITATION IS EXPECTED FOR THIS TAF PERIOD.


&&

.MARINE...
ISSUED AT 320 PM EST TUE NOV 25 2014

LATEST LOCAL RUN OF THE GLERL WAVE MODEL SUPPORTS THE CURRENT
FORECAST. TIMING THEREFORE STILL LOOKS GOOD FOR A LATE EVENING
CANCELLATION/EXPIRATION OF THE SMALL CRAFT ADVISORY.


&&

.HYDROLOGY...
ISSUED AT 255 PM EST TUE NOV 25 2014

SEVERAL LOCATIONS ON AREA RIVERS REMAIN AT OR ABOVE ADVISORY
CRITERIA. MANY LOCATION HAVE REACHED THEIR PEAK AND ARE BEGINNING
THEIR DECLINE...WHILE A FEW OTHERS WILL SEE CRESTS OVER THE NEXT
48 HOURS OR SO. THERE ARE A FEW CHANCES AT PRECIPITATION THROUGH
THE WEEK BUT IT MOSTLY LOOKS TO BE IN THE FORM OF SNOW AND MAINLY
IN THE LIGHTER VARIETY. PRECIPITATION IS ALSO SPREAD OUT OVER
THE COURSE OF SEVERAL DAYS. THIS IS ANTICIPATED TO HAVE
LITTLE...IF ANY...AFFECT ON AREA RIVERS. WE SHOULD SEE IMPROVING
CONDITIONS AS WE GET LATER INTO THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR LMZ844>849.

&&

$$

SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...93
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...TJT






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