HAMweather.com Area Forecast Discussion for County Warning Area GRR

Thu, 16 Feb 2012 07:04:39 GMT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1130 PM EST WED FEB 15 2012

.SYNOPSIS...
ISSUED AT 310 PM EST WED FEB 15 2012

RAIN WILL MOVE INTO THE REGION VERY LATE TONIGHT AND MAY MIX WITH 
SNOW AT TIMES THROUGH LATE THURSDAY MORNING. SOME SNOW ACCUMULATION 
MAY OCCUR THURSDAY MORNING...THOUGH THIS IS MAINLY EXPECTED NORTH OF 
I-96. 

ONLY LIGHT SNOW WILL BE POSSIBLE THIS WEEKEND...WITH A MORE 
ORGANIZED STORM SYSTEM POTENTIALLY AFFECTING THE GREAT LAKES REGION 
TUESDAY AND WEDNESDAY. 

.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 310 PM EST WED FEB 15 2012

MINIMAL IMPACTS EXPECTED AT THIS TIME FROM APPROACHING SYSTEM THAT 
WILL BRING RAIN TONIGHT AND A MIX OF RAIN AND SNOW EARLY THURSDAY. 

RAIN WILL SPREAD INTO THE REGION TONIGHT WITH A MIX OF RAIN AND SNOW 
SHOULD DEVELOP MAINLY NORTH OF I-96 AROUND OR SHORTLY AFTER MIDNIGHT 
TONIGHT. SOME LOCATIONS WILL SEE A COMPLETE CHANGE OVER TO SNOW BY 
SUNRISE THURSDAY...ESPECIALLY THOSE PLACES FURTHER TO THE 
NORTH...WITH SOME ACCUMULATION OF SNOW POSSIBLE BEGINNING BEFORE 
SUNRISE. 
 
ANY ACCUMULATIONS LOOK TO BE AROUND AN INCH TO TWO INCHES ESPECIALLY 
IN MASON...LAKE...OSCEOLA AND CLARE COUNTIES...ALONG WITH THE 
NORTHERN PORTIONS OF OCEANA...NEWAYGO...MECOSTA AND ISABELLA 
COUNTIES. THIS SNOW SHOULD ACCUMULATE SLOWLY THROUGH EARLY THURSDAY 
AFTERNOON SO MINIMAL TRAVEL IMPACTS ARE EXPECTED AT THIS TIME. 

PRECIPITATION COMES TO AN END EARLY THURSDAY AFTERNOON WITH COOLER 
TEMPERATURES FILTERING IN THURSDAY NIGHT. SOME LAKE EFFECT FLURRIES 
MAY BE POSSIBLE THROUGH THURSDAY NIGHT...BUT VERY LITTLE IF ANY 
ACCUMULATION IS EXPECTED.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 310 PM EST WED FEB 15 2012

FORECAST CONCERNS DEAL WITH TWO SYSTEMS MOVING ACROSS THE GREAT 
LAKES. BOTH THE GFS AND ECMWF ARE HANDLING BOTH OF THEM IN SIMILAR 
FASHION. 

A CLIPPER IS PROGD TO MOVE FROM THE NRN PLAINS SOUTH EAST TO SRN 
WISCONSIN BY FRIDAY NIGHT. WE/LL SEE SOME LIGHT SNOW DEVELOP FRIDAY 
EVENING AND CONTINUE INTO SATURDAY. THERE IS SOME UVV/S BUT MAINLY 
BELOW THE DGZ. GIVEN THE LACK OF DEEP MOISTURE WITH THIS SYSTEM ANY 
ACCUMS WE SEE SHOULD BE LESS THAN AN INCH. SUNDAY AND MONDAY LOOK 
DRY AS HIGH PRESSURES MOVES IN TO REPLACE THE CLIPPER. 

ANOTHER STRONGER SYSTEM THEN WILL PROGRESS FROM THE CENTRAL ROCKIES 
NEWED TOWARD WRN LAKE SUPERIOR. THIS PLACES THE CWA ON THE WARM SIDE 
AND WE/LL LIKELY SEE SOME LIGHT RAIN OR MIXED PCPN MONDAY NIGHT AND 
TUESDAY. THE LATEST ECMWF SHOWS A WAVE DEVELOPING OVER THE LOWER 
MISSISSIPPI VALLEY ON THE TRAILING COLD FRONT AND MOVING NEWD TOWARD 
LOWER MICHIGAN WEDNESDAY AND PHASING WITH ANOTHER STRONGER CLIPPER. 
THE GFS SHOWS THIS PHASING NICELY...THE ECMWF IS A A BIT SLOWER WITH 
THE PHASING. IF THE PHASING OCCURS...WE/LL LIKELY NEED HIGHER POPS 
WEDNESDAY.

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY MORNING)
ISSUED AT 1130 PM EST WED FEB 15 2012

IFR TO LIFR CONDITIONS TO CONTINUE OVERNIGHT AT ALL THE TERMINALS 
DUE TO LOW CLOUDS/LIGHT RAIN/LIGHT FOG. LIGHT RAIN WILL GRADUALLY 
TAPER OFF FROM WSW TO ENE DURING THE MID TO LATE MORNING HRS 
THURSDAY. AS THIS OCCURS WINDS WILL SHIFT TO THE WEST AND CONDITIONS 
SHOULD GRADUALLY IMPROVE INTO THE MVFR FLIGHT CATEGORY BY MID TO 
LATE THURSDAY MORNING. 

.MARINE...
ISSUED AT 310 PM EST WED FEB 15 2012

WINDS UP TO 20 KNOTS WILL CONTINUE THROUGH THIS EVENING BEFORE 
DECREASING OVERNIGHT. WINDS WILL INCREASE UP TO 20 KNOTS AGAIN LATE 
THURSDAY MORNING AND REMAIN BREEZY THROUGH THURSDAY EVENING. 

.HYDROLOGY...
ISSUED AT 310 PM EST WED FEB 15 2012

0.25 TO 0.50 INCHES OF RAIN IS EXPECTED TO FALL THURSDAY. THIS WILL 
MELT SNOW PACK IN PLACE AND RESULT IN AREA STREAMS AND RIVERS TO 
RISE. THIS RISE IN WATER LEVELS IS NOT EXPECTED TO RESULT IN ANY 
FLOODING THREATS ACROSS SOUTHWEST LOWER MICHIGAN. 

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