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000
FXUS63 KGRR 062030
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 PM EST FRI MAR 6 2015

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

.SYNOPSIS...
ISSUED AT 330 PM EST FRI MAR 6 2015

WE WILL SEE A SLOW WARM UP OVER THE NEXT WEEK WITH THE WARMEST
TEMPERATURES EXPECTED DURING THE MID WEEK PERIOD. THERE IS A
CHANCE OF LIGHT SNOW NEAR THE LAKE SHORE TONIGHT AND SOME
SCATTERED FLURRIES FROM TIME TO TIME INTO SUNDAY NIGHT BUT NO
SIGNIFICANT SNOW ACCUMULATIONS ARE EXPECTED THROUGH THE WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 330 PM EST FRI MAR 6 2015

THERE IS THE CHANCE OF A PERIOD OF LIGHT SNOW SHOWERS WEST OF
US-131 DURING THE MID TO LATE EVENING HOURS...THEN AGAIN DURING
THE MID MORNING HOURS OF SATURDAY HEAD OF THE COLD FRONT. YET
ANOTHER RATHER WEAK SYSTEM COULD BRING SOME LIGHT SNOW SHOWERS
SUNDAY INTO SUNDAY EVENING. OVERALL EXPECT MOSTLY CLOUDY SKIES
WITH TEMPERATURES BETWEEN 25 DEGREES AND 35 DEGREES MOST OF THE
TIME FROM SATURDAY MORNING INTO MONDAY MORNING.

TONIGHT WE HAVE A WARM FRONT HEADING TOWARD LOWER MICHIGAN AHEAD
OF WEAK CLIPPER SYSTEM CURRENTLY NEAR LAKE WINNIPEG. SOUTHWEST
FLOW AHEAD OF THE WARM FRONT IS SHOWN BY ALL OF THE HIGH
RESOLUTION MODELS TO DEVELOP AND AREA OF LOW CLOUDS AND POSSIBLY
EVEN A LITTLE LIGHT SNOW (MOSTLY NEAR AND NORTH OF MUSKEGON) AFTER
9 PM. THERE IS DECENT LIFT BUT IT IS ALL BELOW 5000 FT AND THE AIR
TEMPERATURES ARE MARGINALLY COLD ENOUGH OF LAKE ENHANCEMENT. THE
DEEP MOISTURE AHEAD OF THE FRONT COMES THROUGH DURING THE MID
MORNING HOURS OF SATURDAY SO I HAVE CHANCE POPS FOR THAT TOO. BY
LATE IN THE MORNING SURFACE TEMPERATURES SHOULD BE WARM ENOUGH THAT
ANY PRECIPITATION MAY BE IN THE FORM OF RAIN SOUTH OF I-96 (MORE OR LESS).

ANOTHER WEAKER CLIPPER SYSTEM MOVES THROUGH THE AREA SUNDAY INTO
SUNDAY EVENING BUT THAT HAS EVEN LESS MOISTURE THAN THE SATURDAY
SYSTEM SO I PLAYED DOWN THE POP FOR THAT EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 330 PM EST FRI MAR 6 2015

MINIMAL CONCERNS WITH RELATIVELY GOOD CONFIDENCE FOR TEMPERATURES
NEAR OR SLIGHTLY ABOVE NORMAL AND FOR DRY CONDITIONS. ZONAL FLOW
ALOFT SHOULD PREDOMINATE DURING THE PERIOD WITH SURFACE HIGH
PRESSURE IN CONTROL OVER MUCH OF THE UNITED STATES.

BETTER PROSPECTS FOR PRECIPITATION BEGIN FRIDAY WITH HINTS OF A
PHASING UPPER TROUGH UPSTREAM. HOWEVER...OVERALL FORECAST CERTAINTY
TENDS TO DROP OFF SIGNIFICANTLY AT THIS TIME RANGE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 100 PM EST FRI MAR 6 2015

THROUGH 00Z...MAIN CONCERN IS MVFR RESTRICTIONS IN SNOW AT THE MKG
TERMINAL. CURRENT THINKING IS THAT THIS SHOULD ABATE FAIRLY SOON.
AT THE REMAINING TERMINALS...CONFIDENCE IS HIGH FOR VFR CONDITIONS WITH
NO RESTRICTIONS TO VISIBILITY.

AFTER 00Z...EXPECT IFR CONDITIONS TO DEVELOP AND PERSIST AT LEAST THROUGH
12Z AT MKG. FUEL ALTERNATE VSBY/CIG THRESHOLDS COULD QUITE POSSIBLY
BE MET AFTER 03Z AT GRR WITH MOSTLY LIGHT SNOW SPREADING INTO THE
AREA. AT THE REMAINING TERMINALS...THERE IS LESS CONCERN FOR
RESTRICTIONS...ALTHOUGH THERE WILL BE A SLIGHT CHANCE FOR FUEL
ALTERNATE CIGS BELOW 2000FT AGL AT SOME SITES.


&&

.HYDROLOGY...
ISSUED AT 255 PM EST FRI MAR 6 2015

CURRENT FLOWS ARE GENERALLY BELOW NORMAL ACROSS SOUTHWEST LOWER
MICHIGAN. RISK OF FLOODING FROM LATE WINTER INTO SPRING IS STILL
NEAR NORMAL...BUT BELOW NORMAL OVER THE NEXT WEEK OR SO. RIVER
LEVELS ARE STABLE...AND ICE BREAKUP HAS YET TO OCCUR. THE WARM UP
THIS WEEKEND THROUGH NEXT WEEK IS VERY GRADUAL. WITH HIGHS IN THE
40S AND LOWS BELOW FREEZING...CONDITIONS ARE IDEAL FOR A SLOW
MELTING PROCESS OF SNOW AND RIVER ICE NEXT WEEK. DIRECT SUNLIGHT
HELPS EAT AWAY AT RIVER ICE QUITE A BIT ALSO.

THE OTHER MAJOR FACTOR IS RAINFALL. THE FORECAST FOR NEXT WEEK IS
QUITE DRY. THUS...RIVER LEVELS ARE EXPECTED TO RISE SLOWLY NEXT
WEEK...ESPECIALLY FROM MID WEEK ON. MOSTLY WITHIN BANK RISES ARE
EXPECTED...BUT A FEW SMALLER STREAMS COULD EXCEED BANKFULL.

LOOKING BEYOND NEXT WEEK...CPC CONTINUES TO INDICATE A 50 PERCENT
CHANCE FOR ABOVE NORMAL TEMPERATURES THROUGH MARCH 19. A STRONGER
WARM UP INTO THE 50S OR 60S...ALONG WITH ANY SIGNIFICANT RAINFALL
EVENT WOULD GREATLY INCREASE THE FLOODING RISK. ICE JAMS ARE NOT
EASY TO FORECAST...BUT SERIOUS ICE JAM FLOODING BECOMES A MAJOR
CONCERN WHEN WARM TEMPERATURES AND HEAVY RAIN COMBINE TO RAPIDLY
ELEVATE RIVER LEVELS TO BUST UP ICE COVER.

&&

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

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...EBW