Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Graphics & Text | 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 052329
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
629 PM EST THU MAR 5 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 PM EST THU MAR 5 2015

ANOTHER COLD NIGHT IS EXPECTED TONIGHT...THEN A MODERATING TREND IS
EXPECTED THROUGH THE WEEKEND AND INTO NEXT WEEK. HIGHS TOMORROW WILL
REACH THE 20S...WITH 30S OVER THE WEEKEND. BY THE MIDDLE OF NEXT
WEEK WE SHOULD WARM INTO THE 40S...WITH THE SOUTHERN PORTION OF THE
STATE NEARING 50 ON WEDNESDAY AND THURSDAY. ONLY LIGHT PRECIPITATION
IS EXPECTED INTO EARLY NEXT WEEK. VERY WEAK SYSTEMS MOVING THROUGH
THE GREAT LAKES TOMORROW AND SATURDAY MAY BRING BRIEF PERIODS OF
LIGHT SNOW. ANY ACCUMULATIONS EACH DAY SHOULD BE AN INCH OR LESS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 329 PM EST THU MAR 5 2015

LIMITED CONCERNS THROUGH THE SHORT TERM. NORTHWEST UPPER FLOW
REMAINS IN PLACE...BUT TEMPERATURES WILL BE MODERATING AS THE COLD
CORE OF AIR LIFTS OUT. THE SHORTWAVE SEEN OVER THE DAKOTAS THIS
AFTERNOON WILL SWING THROUGH OUR AREA TOMORROW. ONLY EXPECTING SMALL
CHANCES FOR SNOW. CONFINED THE POPS TO THE NORTHWEST HALF OF THE
FORECAST AREA AS DELTA T/S MAY BE JUST ENOUGH TO AID IN SNOW
GENERATION. LINGERED FLURRIES AREA WIDE FRIDAY NIGHT.

NEXT SHORTWAVE IS SEEN IN THE WATER VAPOR IMAGERY COMING ASHORE IN
BRITISH COLUMBIA. THE SHORTWAVE DIVES SOUTHEAST AND MOVES THROUGH
OUR AREA ON SATURDAY. MOISTURE INCREASES IN THE 1000-700MB LAYER IN
BOTH TIME FRAMES...FRIDAY AND SATURDAY. NOT EXPECTING MUCH EITHER
PERIOD...BUT SOME CHANCES FOR A LITTLE LIGHT SNOW FOR SURE.
OVERALL...A PRETTY QUIET PERIOD.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 329 PM EST THU MAR 5 2015

WARMER TEMPERATURES ARE EXPECTED BY TUESDAY AFTER OUR FINAL CLIPPER
SYSTEM BRINGS SOME LIGHT SNOW TO THE AREA ON SUNDAY.

ONE GOOD SIGN OF A WARM UP IS LOOKING INTO THE STRATOSPHERE THE 30MB
AND 50MB CIRCULATION AROUND THE POLAR VORTEX...WHICH HAS FEATURED A
DEEP TROUGH OVER THE EASTERN UNITED STATES RETREATS INTO SOUTHERN
CANADA BY THE MIDDLE OF NEXT WEEK. MEANWHILE AT 10MB THERE WERE TWO
CENTERS...ONE OVER NORTHEASTERN RUSSIA AND THE OTHER NORTHERN HUDSON
BAY. BY THE MIDDLE OF NEXT WEEK THAT CONSIDERATE OVER THE NORTH
POLE. ALL THIS TELLS ME THE DEEP COLD AIR RETREATS TO THE NORTH OVER
THE NEXT WEEK. THIS GOES ALONG WITH WHAT ONE WOULD FORECAST USING
THE MJO...WHICH IS WARMING FOR ABOUT 2 WEEKS. THUS I AM MORE IN
FAVOR THE ECMWF IDEA OF NOT BRINGING DOWN SO MUCH COLD AIR LATER
NEXT WEEK.

THE OTHER ISSUE THAT LEADS ME TO WANT TO FOLLOW THE ECMWF OVER THE
GFS IS THAT THE NORTHERN STREAM SHORTWAVE THAT CREATES THE COLD
OUTBREAK LATER NEXT WEEK WAS SHARPER ON YESTERDAYS RUN THAN TODAY.
THAT SUGGESTS TO ME THE TENDENCY OF THE MODEL IS TO FLATTEN
THAT SHORTWAVE OVER TIME. THAT WOULD FAVOR THE ECMWF IDEA OF WARM
VERSES COLDER SURFACE TEMPERATURES LATER NEXT WEEK.

ONE OTHER ISSUE IS THE GFS MODEL SOUNDING COMPARED TO THE ECWMF
SUGGEST THE GFS IS COOLING THE LOWER LEVELS TO MUCH DUE TO THE
CURRENT SNOW COVER. THE NEGATIVE FOR THAT THOUGH IS WE ARE UNDER
SURFACE HIGH PRESSURE DURING THE MIDDLE OF NEXT WEEK. THAT LEADS TO
LESS DEEP MIXING SO HIGHS IN THE MID 40S...THAT GOES NICELY WITH THE
1000/925 MB THICKNESS TOOL...WHICH IS MY FAVORITE HIGH TEMPERATURE
FORECASTING TOOL.

AS FOR THE SYSTEM ON SUNDAY...THE BEST DYNAMICS AND JET CORE PASS
NORTH OF MICHIGAN IN SOUTHERN CANADA. EVEN SO BOTH THE ECMWF AND GFS
SHOW SOME WORKABLE MOISTURE TRANSPORT VECTORS NEARLY PARALLEL TO
INTERSTATE 96/94 SUNDAY DURING THE DAY.  SO I EXPECT SOME LIGHT SNOW
BUT NOTHING ONE WOULD HAVE TO SHOVEL.  AFTER THAT MOVES OUT WARMER
TEMPERATURE BEGIN.

BOTTOM LINE IS EXPECT SOME OF THE WARMEST TEMPERATURE SINCE
CHRISTMAS WEEK (YOU MAY REMEMBER HIGHS IN THE 50S ON THE 23RD OF
DECEMBER). DEW POINTS SHOULD NOT GET ABOVE FREEZING SO THE SNOW MELT
WILL BE SLOW...EVEN WITH THOSE WARM TEMPERATURES.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 626 PM EST THU MAR 5 2015

VFR WEATHER IS FORECASTED THROUGH THE PERIOD. A FEW PATCHES OF
MVFR CLOUDS POSSIBLE ALONG THE LAKESHORE EARLY THIS
EVENING...HOWEVER THE CLOUDS ARE EXPECTED TO DIMINISH
TONIGHT...ALONG WITH ANY REMAINING FLURRIES. WINDS WILL STRENGTHEN
AND SHIFT TO THE SOUTHWEST ON FRIDAY. A FEW GUSTS OVER 25 KNOTS
ARE POSSIBLE.

&&

.HYDROLOGY...
ISSUED AT 329 PM EST THU MAR 5 2015

LOW ICE JAM POTENTIAL/FLOODING RISK OVER THE NEXT 7 DAYS.

LATEST SNOW WATER EQUIVALENT ANALYSES INDICATE AROUND AN INCH OR TWO
IS CONTAINED WITHIN THE SNOWPACK INLAND WITH 2-4 INCHES OF LIQUID
EQUIVALENT CLOSER TO THE LAKESHORE. SWE VALUES OF 4+ INCHES ARE MOST
LIKELY IN THE WHITE AND PERE MARQUETTE RIVER BASINS.

A GRADUAL WARM UP IS EXPECTED FRIDAY INTO THE MIDDLE OF NEXT
WEEK...BUT THE LATEST MODELS ARE LESS BULLISH WITH THE WARM AIR.
HIGHS GENERALLY IN THE 40S TO AROUND 50 DEGREES SEEMS REASONABLE
WITH LOWS NEAR OR BELOW FREEZING. GIVEN THE MOSTLY DRY FORECAST
THROUGH NEXT THURSDAY...THIS COULD BE AN IDEAL FORECAST TO SLOWLY
MELT THE SNOWPACK AND CHIP AWAY AT ICE THICKNESS ON AREA RIVERS AND
STREAMS. RISES IN AREA RIVERS MOSTLY BELOW BANKFULL ARE EXPECTED
NEXT WEEK. A FEW SMALLER STREAMS COULD REACH ADVISORY
STAGE...ESPECIALLY FROM AROUND MARCH 11 INTO THE FOLLOWING WEEKEND.
BUT THE MAJOR STEMS OF THE GRAND AND MUSKEGON RIVERS ARE NOT
EXPECTED TO EXCEED BANKFULL NEXT WEEK.

UNTIL FURTHER NOTICE...ANY SIGNIFICANT RAINFALL EVENTS CHANGE THE
DYNAMIC AND INCREASE THE RISK FOR FLOODING.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...WDM
AVIATION...MJS
HYDROLOGY...EBW






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