207
FXUS63 KGRR 201032
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
632 AM EDT FRI MAR 20 2026
KEY MESSAGES
- RAIN SHOWERS THIS MORNING
- WARMUP TODAY INTO SATURDAY, RAIN SATURDAY NIGHT/SUNDAY
- SEASONABLE TEMPERATURES EARLY NEXT WEEK, MOSTLY DRY
DISCUSSION
ISSUED AT 251 AM EDT FRI MAR 20 2026
- RAIN SHOWERS THIS MORNING
AT THIS TIME, WATER VAPOR IMAGES SHOW AN UPPER PV MAX MOVING SOUTHEAST
ACROSS EASTERN LAKE SUPERIOR WHILE AN EXTENSIVE AREA OF PRECIPITATION
IS MOVING ACROSS THE UP AND NORTHERN LOWER MI AHEAD OF THIS FEATURE.
BASED ON LATEST RADAR TRENDS AND GUIDANCE, HAVE EXTENDED POPS FARTHER
TO THE SOUTH AND EAST THIS MORNING. OUR NORTHEAST ZONES IN CENTRAL
INTERIOR LOWER MI SHOULD RECEIVE THE GREATEST AMOUNT OF PRECIPITATION.
SURFACE OBSERVATIONS THERE ARE REPORTING TEMPERATURES IN THE MID TO
UPPER 30S. GIVEN THAT SOUTHEAST TO SOUTH WINDS WILL LIKELY INCREASE
WITH THE APPROACH OF THE ASSOCIATED SURFACE LOW, IT IS UNLIKELY
TEMPERATURES WILL BE ABLE TO DROP TO FREEZING; HENCE, FREEZING RAIN
IS NOT EXPECTED. THIS IS GOOD NEWS TO CENTRAL INTERIOR LOWER MI, WHICH
HAS ALREADY HAD MORE THAN ITS SHARE OF ICE ACCUMULATIONS RECENTLY.
PRECIPITATION SHOULD EXIT THE AREA BY LATE MORNING/EARLY AFTERNOON.
- WARMUP TODAY INTO SATURDAY, RAIN SATURDAY NIGHT/SUNDAY
AFOREMENTIONED SOUTHERLY FLOW TODAY INTO SATURDAY WILL SUPPORT A
WARMUP RANGING FROM NEAR 50 NORTH TO LOWER 60S SOUTH. AT GRAND
RAPIDS, THIS WILL EQUATE TO MID TO UPPER 50S, WHICH IS ABOUT 10
DEGREES ABOVE NORMAL.
A COLD FRONT IS EXPECTED TO PUSH THROUGH SATURDAY NIGHT INTO SUNDAY
WITH MOSTLY POST-FRONTAL PRECIPITATION THAT SHOULD BE CHIEFLY RAIN.
THIS ASSUMPTION OF RAIN IS BASED ON WARM ANTECEDENT TEMPERATURES AND
WHAT APPEARS TO BE A LACK OF DEEP COLD ADVECTION WITH THE SYSTEM
DRIVING THE FRONT. TRENDS HAVE BEEN TO SLOW THIS FRONT, WHICH IS NOT
SURPRISING GIVEN WHAT APPEARS TO BE A DEEP LAYER OF BOUNDARY-PARALLEL
FLOW. THERE IS IN FACT SOME QUESTION ABOUT HOW SOON THIS FRONT EXITS
THE AREA, OR WHETHER IT BECOMES STATIONARY IN THE VICINITY INTO MONDAY.
- SEASONABLE TEMPERATURES EARLY NEXT WEEK, MOSTLY DRY
RUNNING UNDER THE ASSUMPTION (AND MAJORITY REPORT) THAT THE POST-FRONTAL
PRECIPITATION DEPARTS BY LATE SUNDAY, MONDAY WILL SEE THE ADVANCEMENT
OF SURFACE AND MID-LEVEL RIDGING INTO THE REGION. THE FORECAST IS
GENERALLY FOR DRY CONDITIONS, HOWEVER LATEST GUIDANCE SUGGESTS THAT
SHORTWAVES (WHICH ARE DIFFICULT TO PIN DOWN AT THIS FORECAST RANGE)
MAY DRIVE LOW PRECIPITATION CHANCES. HIGHS WILL GENERALLY BE IN THE
40S TO LOW 50S, WHICH IS NEAR NORMAL FOR THIS TIME OF YEAR.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 632 AM EDT FRI MAR 20 2026
MAIN CHANGE WAS TO INCLUDE RAIN OR VCSH AT SOME OF THE TERMINALS
BASED ON RADAR TRENDS SHOWING A MORE SOUTHWESTWARD EXTENT OF
PRECIPITATION CURRENTLY MOVING SOUTHEAST INTO SOUTHWEST LOWER MI.
NO SIGNIFICANT CHANGES TO LLWS EXPECTATIONS, BUT IT'S WORTH NOTING
THAT WINDS IN THE LOWEST COUPLE THOUSAND FEET ARE EXPECTED TO
CHANGE DIRECTION QUITE SIGNIFICANTLY BETWEEN NOW AND 16Z.
FINALLY, THIS UPDATE ALSO WAS MORE SPECIFIC ABOUT INTRODUCING
MVFR CEILINGS TOWARDS 00Z.
MARINE
ISSUED AT 418 AM EDT FRI MAR 20 2026
BASED ON LATEST WIND AND WAVE GUIDANCE, DECIDED TO ISSUE A SMALL
CRAFT ADVISORY FOR OUR CENTRAL MARINE ZONES. WINDS AND WAVES WILL
PEAK SHORTLY AFTER 8 AM, FOLLOWED BY A GRADUAL DECREASE. THE
EXPIRATION TIME OF 8 PM MAY END UP BEING A BIT TOO LONG, SO WOULDN'T
BE SURPRISED IF LATER SHIFTS DECIDE TO CANCEL THIS EARLY.
HYDROLOGY
ISSUED AT 219 PM EDT THU MAR 19 2026
ONLY ONE SITE REMAINS AT OR ABOVE FLOOD STAGE AS OF THIS AFTERNOON.
THE GRAND RIVER AT COMSTOCK PARK IS NOW CRESTING AT MINOR FLOOD
STAGE. THE MAPLE RIVER AT MAPLE RAPIDS WENT BELOW MINOR FLOOD STAGE
THIS MORNING ALLOWING THE WARNING TO BE CANCELLED. WITH LIGHT
AMOUNTS OF PRECIPITATION EXPECTED OVER THE NEXT FEW DAYS, ADDITIONAL
FLOODING IS NOT EXPECTED.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ845>848.
DISCUSSION...TJT/THOMAS
AVIATION...TJT
MARINE...TJT
HYDROLOGY...THOMAS
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