Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 271737
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1237 PM EST FRI FEB 27 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 320 AM EST FRI FEB 27 2015

CONTINUED COLD THROUGH THE WEEKEND WITH SOME LIGHT SNOW POSSIBLE
NEAR LAKE MICHIGAN TODAY AND MORE WIDESPREAD SNOW EXPECTED SUNDAY
AND SUNDAY NIGHT. A BRIEF WARMUP IS EXPECTED ALONG WITH A MIX OF
RAIN AND SNOW TUESDAY AND TUESDAY NIGHT...BEFORE COLD WEATHER
RETURNS FOR THE REST OF NEXT WEEK.

&&

.UPDATE...
ISSUED AT 1030 AM EST FRI FEB 27 2015

I UPDATED THE FORECAST TO HAVE THE LAKE SNOW BAND AS IT MOVES ON
SHORE BE MORE PERSISTENT. THE LATEST NAM12 SHOWS DECENT LIFT IN
THE DGZ WITH ENOUGH MOISTURE TO KEEP THE SNOW BAND GOING INTO
EARLY THIS AFTERNOON. OTHERWISE THE ON GOING FORECAST LOOKS GREAT.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 320 AM EST FRI FEB 27 2015

LITTLE IMPACT WEATHER IN THE SHORT TERM WITH VERY COLD
TEMPERATURES REMAINING AND ONLY SOME LIGHT SNOW POSSIBLE NEAR
LAKE MICHIGAN TODAY. OTHERWISE...MONITORING THE APPROACH OF A
SYSTEM LATE SATURDAY THAT DOES NOT APPEAR TO MOVE THE POSSIBILITY
OF SNOW INTO MICHIGAN UNTIL SUNDAY.

VERY COLD START TO TODAY WITH TEMPERATURES WELL BELOW ZERO AND
SLOW RECOVERY LEADING TO ANOTHER DAY WITH HIGH TEMPERATURES IN
THE 10-20 DEGREE ABOVE ZERO RANGE. SNOW BAND CURRENTLY OVER LAKE
MICHIGAN TO CONTINUE TO SLOWLY WORK INLAND THIS MORNING WEAKENING
AS IT MOVES OVER LAND. A FEW LOCATIONS ALONG THE COAST COULD SEE
A SLOW INCH OR SO THIS MORNING...BUT FOR THE MOST PART JUST A FEW
FLURRIES WEST OF US-131 TODAY AND NO SIGNIFICANT IMPACTS
EXPECTED.

ANOTHER VERY COLD NIGHT AGAIN TONIGHT WITH SOME CLEARING SKIES
BRINGING NEAR ZERO AND BELOW ZERO TEMPERATURES TO LOWER MICHIGAN
AGAIN. SATURDAY AGAIN A COLD DAY WITH INCREASING CLOUDS SATURDAY
NIGHT AHEAD OF AN APPROACHING SYSTEM THAT MAY BRING SOME SNOW TO
THE AREA SUNDAY.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 320 AM EST THU FEB 26 2015

FOCUS REMAINS ON TWO EVENTS IN THE LONG TERM...NAMELY SNOW ON SUNDAY
AND THEN THE SYSTEM FOR NEXT WEEK TUESDAY INTO WEDNESDAY.

REGARDING THE SUNDAY SYSTEM IT APPEARS TO HAVE NUDGED A BIT TO THE
SOUTH...AS THE UPPER WAVE DRIVING THE SNOW DIGS INTO THE GREAT LAKES
REGION MORE. THE AXIS OF HEAVIEST PRECIPITATION IS SOLIDLY ACROSS
INDIANA. THE SNOW SPREADS IN LATE SATURDAY NIGHT WITH THE BULK
FALLING DURING THE DAY ON SUNDAY. THE SNOW SHOULD WIND DOWN SUNDAY
EVENING. AMOUNTS MAY BE JUST A TOUCH LOWER THAN WHAT WE WERE
THINKING LAST NIGHT. MAYBE AN INCH OR SO ACROSS CENTRAL LOWER
MI...AND 2-4 INCHES TOWARDS I-94.

A BRIEF LULL IN THE WEATHER FOR SUNDAY NIGHT INTO MONDAY NIGHT
BEFORE FOCUS SHIFTS TO THE NEXT SYSTEM. THE TUESDAY SYSTEM HAS LOST
A BIT OF MODEL TO MODEL CONTINUITY AGAIN WITH THE GFS BEING
QUICKER...DEEPER AND FURTHER NORTH. THE ECMWF IS SLOWER AND
EVENTUALLY NEARS THE SAME DEPTH OF THE GFS. THE CANADIAN DOESN/T
OFFER MUCH OF A LEAN EITHER WAY BEING WEAKER AND SOUTH.

AT THIS POINT TAKING A STAY THE COURSE TYPE OF APPROACH WITH THE
TUES/WED SYSTEM GIVEN HOW IT EVOLVES. ESSENTIALLY IT IS DRIVEN BY A
SHORTWAVE EJECTING OUT OF THE SOUTHWEST U.S. UPPER TROUGH. THESE
TYPE OF SYSTEMS ARE FICKLE AND TOUGH TO NAIL DOWN DETAILS ON
ESPECIALLY AT RANGE IN THE FORECAST.

AT THIS POINT FORECAST IS FOR LIGHT SNOW...LOW CHANCES...DEVELOPING
MONDAY NIGHT. ON TUESDAY A SNOW...SLEET...FREEZING RAIN MIX CHANGING
TO FREEZING RAIN AND RAIN. BOTH THE GFS AND ECMWF SHOW A SURGE OF
WARMER AIR INTO THE CWA...THE EURO IS JUST SLOWER WITH IT. MY
INTUITION TELLS ME TO GO WITH THE SLOWER EURO GIVEN A DIGGING TROUGH
DOWN THE WEST COAST. SLOWER IS USUALLY THE WAY TO GO GIVEN THIS
PATTERN. MIX OF RAIN AND SNOW TUESDAY NIGHT CHANGING BACK TO SNOW ON
WEDNESDAY. BOTTOM LINE WE HAVE A WAYS TO GO YET IN DETERMINING THE
FINE DETAILS WITH THIS SYSTEM. BIGGEST IMPACT IN OUR AREA LOOKS TO
BE THE FREEZING PRECIPITATION AS THE HEAVIER SNOW SWATH LAYS DOWN
ACROSS NORTHERN LOWER. STAY TUNED FOR FURTHER MODEL ADJUSTMENTS
THOUGH.

COLDER AIR SWEEPS IN BEHIND THE SYSTEM FOR THURSDAY WITH LAKE SNOWS
LIKELY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1237 PM EST FRI FEB 27 2015

MAIN IMPACT TO AVIATION OPERATIONS WILL BE LAKE EFFECT CLOUDS AND
SOME SNOW SHOWERS MOVING INLAND THIS AFTERNOON. THE CLOUD LEVEL
WINDS ARE SHIFTING ONSHORE THIS AFTERNOON...WHICH IS HELPING TO
PUSH LAKE EFFECT INLAND. SOME IFR WAS REPORTED AT KMKG
EARLIER...WHICH HAS SINCE MOVED INLAND. WE EXPECT THAT THE SNOW
SHOWERS WILL WEAKEN THIS AFTERNOON AS THE MAIN BAND MOVING ONSHORE
DISPERSES. KGRR COULD SEE A FEW OF THESE...BUT WE EXPECT MAINLY
MVFR WITH ANY SNOW SHOWERS. SOME BRIEF AND ISOLATED IFR WILL BE
POSSIBLE.

LAKE EFFECT WILL CLEAR OUT OF THE AREA ACROSS THE SRN TERMINALS
THIS EVENING AS THE FLOW BECOMES SW IN THE CLOUD LAYER. KMKG AND
KGRR WILL HOLD ON TO THE VFR DECK INTO SAT MORNING BEFORE IT
EVENTUALLY MOVES NORTH/DISSIPATES. CAN NOT RULE OUT SOME OF THE
CIGS GOING MVFR OVERNIGHT.

&&

.HYDROLOGY...
ISSUED AT 1202 PM EST FRI FEB 27 2015

THE BATTLE CREEK SITE (BTCM4) ON THE KALAMAZOO RIVER HAS SHOWN
SOME ERRONEOUS DATA THROUGH THE MORNING HOURS. THIS HAS BEEN
DETERMINED TO BE CAUSED BY THE EXTREME COLD THAT SETTLED IN
OVERNIGHT. IT HAS SINCE SHOWN SIGNS OF RETURNING BACK TO ITS
ORIGINAL READING AS A RESULT OF THE SUNSHINE THIS AFTERNOON.
COORDINATION WITH LOCAL OFFICIALS HAS NOT REVEALED ANY NEED FOR
CONCERN.

WHILE AREA STREAMS AND RIVERS HAVE BEEN STABLE FOR SEVERAL WEEKS
NOW A RATHER ACTIVE PERIOD AND GRADUAL WARMING TREND IS EXPECTED.
THIS DOES NOT NECESSARILY RAISE ALARM BUT WE SHOULD HEED SPECIFICS
AS TEMPERATURES BEGIN TO INCREASE AND PRECIPITATION APPROACHES.
TOTAL PRECIPITATION THROUGH THE NEXT SEVEN DAYS IS ANTICIPATED TO
REMAIN UNDER AN INCH. THE REAL QUESTION COMES ON TUESDAY...AS TO
THE EXTENT OF WARMTH...PRECIPITATION AMOUNTS AND PRECIPITATION
TYPE. THAT SAID...WE WOULD NEED A MEANINGFUL AMOUNT OF MOISTURE
IN A SHORT PERIOD OF TIME...COUPLED WITH AN EXTENDED PERIOD OF
WARMTH TO CREATE INSTABILITY IN THE CURRENT ICE COVER. AS OF
NOW...NO REAL ISSUES ARE EXPECTED BUT RIVERS WILL BE MONITORED
THROUGH THE NEXT WEEK.

&&

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

$$

UPDATE...WDM
SYNOPSIS...MACZKO
SHORT TERM...MACZKO
LONG TERM...DUKE
AVIATION...NJJ
HYDROLOGY...JAM





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