738  
FXUS63 KGRR 170745  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
245 AM EST WED JAN 17 2018  
 
LATEST UPDATE...  
SYNOPSIS/SHORT TERM/LONG TERM  
   
SYNOPSIS
 
 
ISSUED AT 245 AM EST WED JAN 17 2018  
 
HIGH PRESSURE WILL BRING FAIR WEATHER INTO THE WEEKEND. LOW  
PRESSURE WILL MOVE IN BY SUNDAY, WITH SOUTHERLY WINDS BRINGING  
WARMER TEMPERATURES AND SOME RAIN. THE LOW WILL MOVE BY ON MONDAY  
WITH COLDER TEMPERATURES AND SOME SNOW SHOWERS FOR MONDAY NIGHT.  
 

 
   
SHORT TERM
 
(TODAY THROUGH FRIDAY)  
ISSUED AT 245 AM EST WED JAN 17 2018  
 
NO SIGNIFICANT WEATHER IN THE NEAR TERM. SFC RIDGING TO OUR SOUTH  
AND NORTHERN STREAM CLIPPER PASSING WELL TO OUR NORTH WILL MEAN  
SOME BREEZY CONDITIONS WITH MILDER TEMPERATURES THURSDAY AND  
FRIDAY. NO PRECIPITATION IS EXPECTED BUT WE WILL HAVE TO WATCH FOR  
LOW STRATUS CLOUDS TRAPPED UNDER INVERSION AS MOISTURE ADVECTS IN  
FROM THE SOUTH ON THURSDAY AND FRIDAY. TEMPERATURES SHOULD RISE  
ABOVE FREEZING FRIDAY AFTERNOON ALONG WITH SOME CLEARING AS  
INVERSION IS FORECAST TO WEAKEN BY THAT TIME.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 245 AM EST WED JAN 17 2018  
 
MUCH ABOVE NORMAL TEMPERATURES ARE FORECAST FRIDAY NIGHT THROUGH  
MONDAY BEFORE RETURNING TO NEAR NORMAL BY TUESDAY. A STRONG LOW  
PRESSURE SYSTEM WILL BRING A GOOD CHANCE OF PRECIPITATION FROM LATE  
SUNDAY THROUGH SUNDAY NIGHT INTO MONDAY.  
 
STRONG SW FLOW WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT THROUGH  
THE WEEKEND. DRY WX IS FCST FRIDAY NIGHT THROUGH SATURDAY AFTERNOON.  
A WARM FRONT WILL BRING AN INITIAL MIX OF LIGHT PCPN SATURDAY NIGHT  
INTO SUNDAY MORNING WITH THE HIGH PRESSURE TO THE NORTH STILL  
PROVIDING SOME LOW LEVEL COLD AIR.  
 
HOWEVER ANY MIXED PCPN SHOULD QUICKLY TRANSITION TO RAIN SUNDAY  
GIVEN THE STRENGTH OF THE WARM AIR ADVECTION AND MODERATING THERMAL  
PROFILES. IN FACT HIGH TEMPERATURES BY SUNDAY AND/OR MONDAY COULD  
FLIRT WITH THE 50 DEGREE MARK IN A FEW SPOTS. WE DID NOT FCST TEMPS  
QUITE THAT MILD GIVEN THE LINGERING SNOW COVER AND EXTENSIVE CLOUD  
COVER AND PCPN FORECAST BY THEN.  
 
PERSISTENT SOUTHERLY FLOW OFF THE GULF WILL RESULT IN INCREASING  
MOISTURE AND THE BEST CHANCE FOR RAIN LATE SUNDAY NIGHT AND MONDAY  
AS THE STRONG LOW PRESSURE SYSTEM MOVES FROM THE CENTRAL PLAINS  
STATES SUNDAY TO THE GREAT LAKES REGION MONDAY. TEMPERATURES WILL  
FINALLY COOL AND RETURN TO NEAR NORMAL FOR THIS TIME OF YEAR BY  
TUESDAY BEHIND THAT SYSTEM.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1100 PM EST TUE JAN 16 2018  
 
PRIMARILY VFR CONDITIONS WILL CONTINUE AT MOST OF THE TERMINALS  
THROUGH WEDNESDAY EVENING. AN EXCEPTION TO THIS IS AT KMKG WHERE  
LIGHT SNOW SHOWERS AND FLURRIES MAY CAUSE BRIEF REDUCTIONS TO MVFR  
OVERNIGHT. HOWEVER EVEN THERE VFR SHOULD PREVAIL OVERNIGHT. SOUTHWEST  
WINDS WILL RAMP UP CONSIDERABLY AT ALL THE TERMINALS WEDNESDAY MORNING  
AND FREQUENTLY GUST TO 20-30 KTS THROUGH WEDNESDAY EVENING.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 1230 PM EST TUE JAN 16 2018  
 
THE ICE JAM CONTINUES ALONG THE MUSKEGON RIVER IN MECOSTA COUNTY.  
LATEST INFORMATION FROM EMERGENCY MANAGEMENT IS THAT LITTLE RISE HAS  
BEEN NOTED SINCE IMPACTS FROM THE JAM WERE REPORTED MONDAY EVENING.  
LITTLE OR NO ADDITIONAL IMPACTS HAVE BEEN REPORTED. PREVIOUSLY  
OPEN WATERS HAVE SINCE FROZEN WITH ICE CHUNKS THAT HAVE BUILT IN  
ON THE BACK SIDE OF THE JAM, BUT SEEM TO BE STABLE. GIVEN THE  
LITTLE NOTICEABLE CHANGES, WE COULD BE SEEING THE PEAK, BUT IT  
DOES NOT RULE OUT ICE MOVEMENT AND FURTHER FLUCTUATION. RESIDENTS  
SHOULD CONTINUE TO MONITOR LEVELS AND PAY CLOSE ATTENTION TO  
LATEST UPDATES THAT ARE PROVIDED.  
 
SITES ELSEWHERE ARE SHOWING SOME AFFECTS AS A RESULT OF RIVER ICE,  
BUT SEEM TO BE STABLE. MINOR FLUCTUATIONS HAVE BEEN NOTED WITH  
OVERALL DOWNWARD TRENDS ON RIVERS AT OR NEAR BANKFULL. ONLY ONE  
ADVISORY REMAINS IN EFFECT, BUT IS LIKELY TO BE DROPPED SOMETIME  
LATE THIS EVENING OR OVERNIGHT.  
 
COLDER TEMPERATURES WILL ALLOW ICE TO CONTINUE TO BUILD OVER THE  
NEXT COUPLE OF DAYS. THERE IS CONCERN IN THE UPCOMING WEEKEND AND  
INTO EARLY NEXT WEEK AS TEMPERATURES RISE AND PRECIPITATION  
CHANCES INCREASE. WE COULD SEE A REPEAT OF LAST WEEK WITH MELTING  
SNOW AND RAINFALL. IN ADDITION TO WEAKENING ICE, RUNOFF COULD  
CAUSE RIVERS TO RISE AND LEAD TO ADDITIONAL ICE JAMS.  
 

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

 
 

 
 
SYNOPSIS...OSTUNO  
SHORT TERM...OSTUNO  
LONG TERM...LAURENS  
AVIATION...LAURENS  
HYDROLOGY...JAM  
 
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