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Displaying AFOS PIL: AFDGRR Received: 2015-03-02 17:05 UTC
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582 FXUS63 KGRR 021705 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1205 PM EST MON MAR 2 2015 LATEST UPDATE... HYDRO .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 1205 AM EST MON MAR 2 2015 AREA STREAMS AND RIVERS REMAIN STABLE WITH NO NOTABLE VARIATIONS TO RAISE CONCERNS. THE OVERALL THINKING WITH THE FORECAST IS CONSISTENT WITH PRIOR STATEMENTS IN THE LAST 48 HOURS. SEE-SAW TEMPERATURES ARE EXPECTED OVER THE NEXT SEVERAL DAYS WITH 30S TUESDAY...RETURNING TO THE TEENS AND 20S WEDNESDAY THROUGH FRIDAY. THE STORM SYSTEM TUESDAY BRINGS THE BULK OF THE MOISTURE BEFORE CONDITIONS BECOME RELATIVELY TAME FOR THE REMAINDER OF THE WEEK. QPF IS EXPECTED TO BE AROUND ONE-HALF AN INCH OR LESS AS THE STORM EXITS LATE TUESDAY. MILDER TEMPERATURES ARE SHORT-LIVED AND ARE ONLY BEING CONSIDERED MILD IN RELATIVE TERMS. SNOW ALREADY ON THE GROUND SHOULD SOAK UP MUCH OF WHAT FALLS AS RAIN OR FREEZING RAIN. ANY RIVER RESPONSE SHOULD HOLD OFF UNTIL WE GET A MORE SUSTAINED AND ROBUST WARM PERIOD. FOR THAT...IT MAY NOT BE UNTIL NEXT WEEK. THAT WILL BE SOMETHING TO CONSIDER IN DETAIL AS THE WEEK PROGRESSES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...DUKE SYNOPSIS...04 SHORT TERM...04 LONG TERM...MEADE AVIATION...LAURENS HYDROLOGY...JAM