National Weather Service Raw Text Product

152 
FXUS63 KGRR 021641
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1141 AM EST MON MAR 2 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 328 AM EST MON MAR 2 2015

PARTLY TO MOSTLY SUNNY SKIES WILL COVER THE GREAT LAKES TODAY BEFORE 
LOW PRESSURE SPREADS A MIX OF SNOW SLEET FREEZING RAIN AND RAIN INTO 
LOWER MICHIGAN TUESDAY. SEVERAL INCHES OF SNOW ARE POSSIBLE NORTH OF 
I-96 TUESDAY AND UP TO A TENTH OF AN INCH OF ICE SOUTH OF I-96. 
ANOTHER BLAST OF ARCTIC AIR WILL FLOW OVER THE STATE THURSDAY WHEN 
HIGHS ONLY REACH THE TEENS. WARMER WEATHER IS EXPECTED BY THE 
WEEKEND. 

&&

.UPDATE...
ISSUED AT 1128 AM EST MON MAR 2 2015

FOCUS REMAINS ON THE SYSTEM FOR TOMORROW. AT THIS POINT HAVE NOT
MADE ANY CHANGES TO TOMORROW/S FORECAST. WE WILL BE PERUSING ALL
OF THE 12Z GUIDANCE AND MAKING ANY TWEAKS NECESSARY THIS AFTERNOON.
STILL ANTICIPATING A MIX OF PRECIP TYPES ACROSS THE FORECAST AREA
NAMELY...SNOW...SLEET...FREEZING RAIN AND RAIN. EXPECTING THAT WE
WILL NEED A WINTER WEATHER ADVISORY FOR PROBABLY THE ENTIRE
FORECAST AREA ON TUESDAY. THE ADVISORY CALL WILL LIKELY BE MADE
WITH THE AFTERNOON FORECAST PACKAGE WHEN WE HAVE TIME TO LOOK AT
THE FINE DETAILS OF THE 12Z DATA.

DID NOT MAKE MUCH IN THE WAY OF CHANGES TO THE AFTERNOON FORECAST.
PARTLY TO MOSTLY SUNNY SKIES LOOK SOLID WITH A BIT OF STRATOCU
COMING OFF THE LAKE WITH DELTA T/S IN THE LOWER TEENS C. SOME
CIRRUS AND ALTOCU WILL BE SPREADING IN FROM THE SOUTHWEST TOWARDS
EVENING AS WELL. HIGH TEMPERATURES WILL TOP OUT IN THE 25 TO 30
DEGREE RANGE IN MOST AREAS.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 328 AM EST MON MAR 2 2015

LITTLE CHANGE TO THE GOING FORECAST. CONCERNS DEAL WITH THE 
APPROACHING LOW PRESSURE SYSTEM TUESDAY. 

LOW PRESSURE EMERGING FROM THE CENTRAL ROCKIES WILL MAKE A BEELINE 
TOWARD THE GREAT LAKES TONIGHT AND TUESDAY ON THE HEELS OF A 180KT 
UPPER JET THAT PASSES OVER THE CENTRAL CWA. FOR SEVERAL DAYS SHORT 
RANGE MODELS HAVE BEEN SHOWING THIS LOW PHASING WITH A LOW MOVING 
ACROSS SOUTHERN CANADA. THIS PHASING CREATES A POTENT SYSTEM AND 
WE/LL SEE AROUND A HALF INCH QPF FROM IT. STRONG ISENTROPIC LIFT ON 
THE 290K SFC QUICKLY SATURATES THAT COLUMN AFTER 06Z TONIGHT AND WE 
SHOULD SEE SNOW DEVELOP BY 4-5 AM. INITIALLY FORECAST SOUNDINGS ARE 
COLD ENOUGH TO SUPPORT ALL SNOW FOR THE CWA WHICH WILL ACTUALLY BE 
GOOD NEWS IN THE SOUTHERN CWA WHERE WE/LL SEE SOME FREEZING RAIN 
DEVELOP LATER IN THE DAY. TO HAVE SOME SNOW TO ABSORB THE RAIN AND 
PROVIDE SOME GRIT ON THE ROADS MAY BE A GOOD THING AS THE COLUMN 
WARMS AROUND 800 MB AND THE SNOW TURNS TO RAIN. LOOKING AT SOUNDINGS 
FROM THE ECMWF/GFS/NAM...THEY GENERALLY SUPPORT MOSTLY SNOW NORTH OF 
M-46. IN THIS AREA 3-5 INCHES SEEMS POSSIBLE TUESDAY. SOUTH OF THERE 
IT/S LOOKING LIKE A 1-3 INCH SNOWFALL WITH UP TO A TENTH OF AN INCH 
OF FREEZING RAIN. SOME SLEET IS ALSO POSSIBLE DURING THE TRANSITION 
PERIODS. THE MAIN SURGE OF WARMER AIR ACTUALLY COMES IN AROUND 21Z 
THROUGH 01Z OR SO AND WE COULD SEE SOME RAIN SOUTH OF I-94. GIVEN 
THE COLD GROUND TEMPERATURES...SECONDARY ROADS MAY REMAIN COLD 
ENOUGH DESPITE TEMPERATURES RISING ABOVE FREEZING SOUTH OF I-96 TO 
SEE MOSTLY FREEZING RAIN. THUS ICY CONDITIONS WILL BE MORE PREVALENT 
ON DIRT/GRAVEL ROADS...ALTHOUGH HAVING SOME SNOW ON THE GROUND WILL 
PROBABLY HELP. 

THE TRAILING COLD FRONT MOVES THROUGH AROUND 00Z AND WE/LL SEE A 
TRANSITION BACK TO LIGHT SNOW TUESDAY EVENING. BREEZY CONDITIONS 
WILL DEVELOP TUESDAY EVENING AS HIGH PRESSURE QUICKLY BUILDS IN AND 
THE GRADIENT TIGHTENS. SNOW SHOWERS ARE POSSIBLE WEDNESDAY AS H8 
TEMPS FALL TO -24C...BUT GIVEN THE LIMITED MOISTURE BEHIND THE FRONT 
WE ARE NOT EXPECTED MUCH IN THE WAY OF ACCUMS.   

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 AM EST MON MAR 2 2015

AFTER ANOTHER SHOT OF BITTER COLD AIR FOR THE MID WEEK PERIOD WITH 
TEMPERATURES 25 DEGREES BELOW NORMAL... IT LOOKS LIKE WE MAY FINALLY 
SEE TEMPERATURES ABOVE FREEZING NEXT WEEKEND.

LAKE EFFECT SNOW SHOWERS ARE EXPECTED WEDNESDAY NIGHT AND THURSDAY 
AS OUR NEXT INSTALLMENT OF ARCTIC AIR WITH H8 TEMPS AROUND -22C 
SLIDES ACROSS A STILL OPEN LAKE MICHIGAN. THE UPPER TROUGH AND CORE 
OF THE COLDEST H8 AIR ARE SHOWN TO IMPACT THE AREA DURING THIS TIME 
SO WILL CARRY LIKELY POPS WEST OF HIGHWAY 131 WITH A FEW INCHES OF 
ACCUMULATION POSSIBLE. 

MOISTURE LOOKS SHALLOW BUT THE DGZ SHOULD BE IN CLOUD LAYER. THE 
BEST CHANCE FOR ACCUMULATIONS ALONG THE LAKESHORE WOULD BE LATER 
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING WHEN SFC CONVERGENCE IS 
MAXIMIZED. 

MODERATING TEMPERATURES ARE EXPECTED FRIDAY AND SATURDAY AS THE NRN 
STREAM RETREATS AND THE UPR FLOW GOES MORE ZONAL. ITS QUESTIONABLE 
HOW WARM WE GET GIVEN THE EXPANSIVE SNOW COVER AND UNCERTAINTY IN 
AMOUNT OF CLOUD COVER... BUT TEMPS ABOVE FREEZING ARE CERTAINLY 
POSSIBLE ON SATURDAY. THE GFS IS DRIVING ANOTHER COLD FRONT THROUGH 
ON SATURDAY NIGHT WHICH WOULD HALT THE WEEKEND WARM UP BUT THE ECMWF 
DOES NOT SHOW THIS FRONT. 

LOOKING EVEN FARTHER AHEAD.... BOTH THE ECMWF AND GFS SHOW THE 
POSSIBILITY OF ONE MORE ARCTIC SURGE ON MON-TUE MARCH 9-10. IT IS 
BEHIND THIS THAT THE PATTERN CHANGE TOWARD WARMER TEMPERATURES MAY 
FINALLY ENSUE BY LATER THAT WEEK. 

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1130 AM EST MON MAR 2 2015

MVFR/VFR CONDITIONS WILL CONTINUE THIS AFTERNOON AND EVENING AND FOR 
MOST OF THE OVERNIGHT PERIOD. CONDITIONS WILL DETERIORATE RAPIDLY TO 
IFR/LIFR DURING THE MID MORNING HOURS TUESDAY AS SNOW DEVELOPS. 

SNOW WILL BECOME MIXED WITH AND/OR CHANGE OVER TO SLEET AND LIGHT 
FREEZING RAIN TOWARD MIDDAY SO A LIGHT ICING THREAT WILL EXIST AS 
WELL. 

LIFR/IFR CONDITIONS WILL THEN CONTINUE THROUGH 18Z DUE TO LOW CIGS 
AND MIXED PCPN. IT WILL ALSO BECOME WINDY BY MID TO LATE MORNING A 
SE WINDS RAMP UP TO 15 TO 20 KTS WITH GUSTS TO NEAR 25 KTS.

&&

.HYDROLOGY...
ISSUED AT 1140 AM EST SUN MAR 1 2015

THE FORECAST GETS A LITTLE TRICKY IN THE UPCOMING WEEK WITH THE
APPROACHING SYSTEM GOING INTO TUESDAY. TEMPERATURES COULD VARY
QUITE A BIT RIGHT ALONG WITH EXPECTED PRECIPITATION TOTALS AND
PRECIPITATION TYPE. THE CURRENT GUIDANCE SUGGESTS WE COULD GET A
BIT FURTHER INTO MILDER AIR (NEAR NORMAL) AND ADD MORE LIQUID
PRECIPITATION AS OPPOSED TO SNOW. OVERALL....IT IS NOT A DRASTIC
WARM UP AND AMOUNTS MAY REMAIN AROUND OR BELOW HALF AN INCH. THIS
COULD MOSTLY BE SOAKED UP BY CURRENT SNOW PACK. WITH LOW RIVER 
LEVELS AND GIVEN SITUATION...THIS SHOULD NOT RAISE ANY IMMEDIATE
CONCERN BUT WILL BE ADDED LIQUID TO BE CONSIDERED IN FORECASTS
DOWN THE ROAD.

THE GOOD NEWS IS THAT THE SYSTEM LAST NIGHT INTO TODAY WAS QUITE
LACKLUSTER IN REGARDS TO TOTALS. THEREFORE...WHAT WE MISSED LAST
NIGHT WILL JUST SUBTRACT FROM THE OVERALL WEEKLY AMOUNTS WE WERE
LOOKING AT YESTERDAY. THOUGH IT WAS NOT ANYTHING TOO HEAVY TO
BEGIN WITH IT JUST RAISES CONFIDENCE THAT ANY UPWARD TRENDS IN
TEMPERATURES WILL NOT HAVE AS MUCH OF A NEGATIVE IMPACT.
CONDITIONS ARE EXPECTED TO REMAIN STABLE FOR NOW AND IN THE NEAR
TERM.

&&

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

$$

UPDATE...DUKE
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...LAURENS
HYDROLOGY...JAM