624  
FXUS63 KGRR 191930  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
330 PM EDT SUN MAY 19 2019  
 
LATEST UPDATE...  
SYNOPSIS/DISCUSSION/MARINE/HYDRO  
   
SYNOPSIS
 
 
ISSUED AT 330 PM EDT SUN MAY 19 2019  
 
-SHOWERS AND THUNDERSTORMS ENDING THIS EVENING  
 
-BREEZY AND CHILLY MONDAY; PATCHY FROST POSSIBLE MONDAY NIGHT  
NORTH OF I-96  
 
-REBOUNDING TEMPERATURES FOR MID TO LATE WEEK WITH SHOWER AND  
THUNDERSTORMS POTENTIAL RETURNING.  
 

 
   
DISCUSSION
 
(THIS EVENING THROUGH NEXT SUNDAY)  
ISSUED AT 330 PM EDT SUN MAY 19 2019  
 
NARROW WINDOW OF POTENTIAL SVR TSTMS WITH DAMAGING WINDS STILL  
EXISTS BETWEEN 4 PM AND 9 PM THIS EVENING AS MID LEVEL SHORTWAVE  
AND SFC COLD FRONT COME THROUGH THE AREA. HIGH SHEAR/LOW CAPE  
ENVIRONMENT WITH MLCAPES ONLY AROUND 500 J/KG BUT 0-6 KM SHEAR OF  
70-75 KTS.  
 
A BRIEF AREA OF CLEARING IS NOW SPREADING IN FROM THE WEST AND  
UPSTREAM STORM REPORTS INDICATE A HISTORY OF LOCALIZED SVR WIND  
GUSTS AROUND MILWAUKEE AND CHICAGO. THIS SCATTERED CONVECTION MAY  
TEMPORARILY WEAKEN OVER THE COLD WATERS OF THE LK MI BUT THEN RE-  
INTENSIFY AGAIN ONCE OVER LAND IN WRN LWR MI.  
 
LATEST CAMS INDICATE A SCATTERED TO BROKEN LINE OF STRONG  
CONVECTION ALONG THE LAKESHORE AT 21Z, REACHING THE LAN/JXN AREAS  
AROUND 00Z. POOR MID LEVEL LAPSE RATES OF 5.5 TO 6 C/KM ARE  
A LIMITING FACTOR, BUT IF LINE OF STORMS CAN SOMEHOW CONGEAL AND  
DEVELOP A COLD POOL, THE DAMAGING WIND THREAT WILL INCREASE AS THE  
STORMS MOVE EAST AT NEARLY 50 KTS EARLY THIS EVENING.  
 
STORM THREAT ENDS AFTER 9 PM THEN DRY BUT BREEZY AND TURNING COOL  
TONIGHT. EXTENSIVE LOW LEVEL CLOUDINESS WILL POUR IN LATE TONIGHT  
AND EARLY MONDAY BEHIND THE FRONT, LINGERING MUCH OF TOMORROW.  
INCOMING SFC RIDGE SHOULD BRING DECREASING CLOUDS MID TO LATE  
AFTERNOON AS WELL AS DIMINISHING WINDS. WILL NEED TO CONSIDER A  
POTENTIAL FROST ADVISORY FOR MONDAY NIGHT UP NORTH WITH LIGHT  
WINDS AND CLR SKIES UNDER THE SFC RIDGE.  
 
WARM FRONT WILL START LIFTING BACK NORTH LATE TUESDAY NIGHT AND  
WEDNESDAY, BRINGING OUR NEXT CHANCE OF SHOWERS AND TSTMS. THURSDAY  
AND FRIDAY LOOK LIKE WARM/HUMID DAYS WITH THE WARM FRONT PROBABLY  
TO OUR NORTH, BUT ISOLATED DIURNAL SHOWERS OR STORMS COULD STILL  
DEVELOP.  
 
THE UPCOMING HOLIDAY WEEKEND COULD FEATURE PERIODIC SHOWERS AND  
TSTMS WITH THE FRONTAL BOUNDARY DRAPED ACROSS THE REGION. DAILY HIGH  
TEMPS WILL BE TRICKY SINCE COOL READINGS ARE LIKELY NORTH OF THE  
BOUNDARY WITH SUMMERLIKE READINGS AND HUMID CONDITIONS TO THE  
SOUTH.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)  
ISSUED AT 150 PM EDT SUN MAY 19 2019  
 
SCATTERED RAIN SHOWERS AND OCNL MVFR CIGS ARE EXPECTED THROUGH  
AROUND 20Z, FOLLOWED BY A ROUGHLY 4 HOUR WINDOW BETWEEN 20Z AND  
00Z IN WHICH TSTMS, SOME STRONG, MAY IMPACT THE TERMINALS. THESE  
STORMS COULD CONTAIN SOME BRIEF GUSTY WINDS IN EXCESS OF 40KTS AND  
HEAVY DOWNPOURS WHICH PRODUCE IFR VSBYS.  
 
TSTM THREAT ENDING AFTER 00Z BUT GUSTY WEST WINDS TO 25 KTS  
CONTINUING. WIDESPREAD MVFR CIGS OVERSPREADING THE REGION AFTER  
06Z TONIGHT AND REMAINING IN PLACE MONDAY MORNING WITH THE GUSTY  
WEST WINDS BECOMING NORTHWESTERLY BY NOON MONDAY.  
 

 
   
MARINE
 
 
ISSUED AT 330 PM EDT SUN MAY 19 2019  
 
NO CHANGE TO THE SMALL CRAFT ADVISORY. STILL CONCERNED ABOUT SOME  
POTENTIAL BEACH EROSION TONIGHT WITH WESTERLY WIND TRAJECTORY  
BEHIND THE COLD FRONT AND 4-6 FT WAVES, BUT CONFIDENCE NOT HIGH  
ENOUGH TO ISSUE LAKESHORE FLOOD ADVISORY. WINDS AND WAVES  
DIMINISHING LATE MONDAY AND ESPECIALLY MONDAY NIGHT.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 330 PM EDT SUN MAY 19 2019  
 
RAINFALL SINCE THE LOCALLY HEAVY RAINFALL FRIDAY NIGHT HAS BEEN  
LIMITED IN NATURE, WITH NO REAL IMPACTS FOR MOST AREAS. THE  
EXCEPTION TO THIS HAS BEEN AT VICKSBURG WHERE THE LEVEL HAS COME UP  
TO NEAR FLOOD STAGE. EMERGENCY MANAGEMENT AND RIVER OBSERVERS  
INDICATE NO THREAT TO HOMES OR PEOPLE, SO WE HAVE HELD OFF ON  
HEADLINES FOR NOW, AND WILL CONTINUE TO MONITOR.  
 
WE ARE NOT EXPECTING ANY SIGNIFICANT AMOUNTS OF RAINFALL THIS  
EVENING WITH THE STORMS, OR THROUGH THE COMING WORK WEEK. THERE WILL  
BE A COUPLE OF CHANCES OF RAINFALL, HOWEVER THESE SYSTEMS LOOK  
PROGRESSIVE, AND SHOULD NOT HAVE ALL OF THE INGREDIENTS NEEDED FOR  
HEAVY RAIN EVENTS.  
 
FLOODING ALREADY OCCURRING DUE TO HIGH LAKE MICHIGAN WATER LEVELS  
MAY WORSEN A BIT WITH STIFF SOUTHWEST TO NORTHWEST WINDS TONIGHT  
INTO MONDAY.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT MONDAY FOR LMZ844>849.  
 

 
 

 
 
SYNOPSIS...MEADE  
DISCUSSION...MEADE  
AVIATION...MEADE  
HYDROLOGY...NJJ  
MARINE...MEADE  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MI Page
The Nexlab IN Page Main Text Page