480
FXUS63 KGRR 291945
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
245 PM EST WED JAN 29 2025
KEY MESSAGES
- MIXED PRECIPITATION EVENT THURSDAY NIGHT INTO FRIDAY
- RAIN/SNOW CHANCES SUNDAY AND WARMER EARLY NEXT WEEK
- QUIET AND COOLER MID-WEEK
DISCUSSION
ISSUED AT 245 PM EST WED JAN 29 2025
- MIXED PRECIPITATION EVENT THURSDAY NIGHT INTO FRIDAY
CLOUDS CONTINUE TO SLOWLY ERODE FROM SW TO NE THIS AFTERNOON AS THE
UPPER JET LIFTS NE AWAY FROM THE AREA. THIS IS SETTING THE AREA UP
FOR SOME SUNSHINE TO FINISH TODAY AND QUITE A BIT ALSO FOR THURSDAY.
THE WINDS ARE ALSO DIMINISHING SOME THIS AFTERNOON, AND SHOULD NOT
BE ANY STRONGER ON THURSDAY, COMPARED TO THIS AFTERNOON.
THE NEXT LIMITED IMPACTFUL SYSTEM HAS ITS EYES SET ON THE AREA
DURING THE THURSDAY NIGHT INTO FRIDAY TIME FRAME. THE UPPER LOW NEAR
THE FOUR CORNERS REGION THIS AFTERNOON WILL BE RESPONSIBLE FOR THE
THURSDAY NIGHT/FRIDAY PRECIPITATION CHANCES. THIS LOW WILL BE
GETTING PUSHED OUT BY ENERGY OVER THE MIDDLE OF THE PACIFIC AND THE
RIDGE MOVING ONSHORE OVER THE WEST U.S. COAST. THIS UPPER LOW WILL
BE SLOWLY OPENING UP AND WEAKENING AS IT MOVES TOWARD THE REGION
THURSDAY NIGHT AND FRIDAY.
THE MAIN UNCERTAINTY WITH THIS SYSTEM FOR OUR AREA WILL BE HOW FAR
NORTH DOES THE PRECIPITATION MAKE IT, AND HOW MUCH OF A WINTRY MIX
COULD OCCUR WITH IT. THE NORTHWARD PROGRESS OF THE SYSTEM WILL BE
LIMITED BY THE CLOSED MID LEVEL LOW OPENING UP, AND WITH A DRY FLOW
FROM THE NE ON THE NORTHERN EDGE OF IT. FORTUNATELY THIS SYSTEM
LOOKS LIKE IT WILL BE PRIMARILY RAIN THAT WILL KEEP THE IMPACTS
LOWER. THIS IS THE RESULT OF IT BEING A SOUTHERN STREAM SYSTEM, WITH
NO DEEP COLD AIR AVAILABLE TO IT. 850 MB TEMPS WILL BE MOSTLY ABOVE
FREEZING UNTIL LATE FRIDAY.
THERE MAY BE SOME VERY LIGHT FREEZING RAIN ACROSS CENTRAL LOWER
WHERE SFC TEMPS WILL BE A TOUCH BELOW FREEZING AS THE RAIN BEGINS TO
FALL THURSDAY NIGHT. THIS WILL BE SHORT LIVED HOWEVER AS THE RAIN
WILL BRING THE WARMER AIR FROM ALOFT DOWN TO THE SFC. THERE MIGHT BE
A BRIEF LIGHT GLAZE NORTH OF I-96 BEFORE TEMPS GO ABOVE FREEZING.
THEN SNOW WILL TRY TO MIX IN WITH THE RAIN ON THE BACK END OF THE
PRECIPITATION AS TEMPS ALOFT DROP BELOW FREEZING JUST BEFORE THE
PRECIPITATION ENDS.
- RAIN/SNOW CHANCES SUNDAY AND WARMER NEXT WEEK
WE WILL SEE A BREAK IN THE PRECIPITATION CHANCES ON SATURDAY AS HIGH
PRESSURE BUILDS IN OVER THE AREA. MUCH COOLER TEMPERATURES CAN BE
EXPECTED WITH 850 MB TEMPS DROPPING TO AS LOW AS -3C TO -8C. THIS
AIR IS NOT QUITE COLD ENOUGH TO FACILITATE LAKE EFFECT. PLUS, THE
FLOW WILL BE COMING IN FROM THE NE.
CLOUDS AND PRECIPITATION WILL MOVE BACK IN BY SUNDAY ACROSS THE
AREA. WE WILL SEE A NORTHERN STREAM SHORT WAVE RIDE ALONG THE
U.S./CANADIAN BORDER JUST NORTH OF OUR AREA. PRECIPITATION WILL
BEGIN LATE SATURDAY NIGHT AND SUNDAY MORNING OUT AHEAD OF A
STRENGTHENING WARM FRONT AHEAD OF THE SYSTEM. THIS LOOKS TO BE
ANOTHER MIXED TYPE OF EVENT AT THE ONSET AS WARMER AIR WILL BE
OVERRIDING THE RESIDUAL COLDER AIR FROM SATURDAY. THE CHANGEOVER
WILL BE QUICK TO CHANGE TO RAIN AGAIN BEFORE ENDING SUNDAY
MORNING WITH THE AREA GETTING INTO THE WARM SECTOR.
850 MB TEMPS RISING INTO THE MID SINGLE DIGITS ABOVE 0C WILL SUPPORT
HIGHS ON SUNDAY INTO THE 40S. MUCH OF THE DAY LOOKS DRY BEHIND THE
WARM FRONT, AND AHEAD OF THE COLD FRONT THAT WILL COME THROUGH
MONDAY MORNING. THE COLD FRONT WILL BRING A SMALL CHANCE OF RAIN
SHOWERS, BUT THERE IS JUST NOT MUCH MOISTURE TO WORK WITH AT THAT
TIME.
- QUIET AND COOLER MID-WEEK
THE AIR BEHIND THE FRONT THAT COMES THROUGH EARLY MONDAY WILL NOT BE
SIGNIFICANTLY COLDER. THIS IS BECAUSE THE ORIGIN OF THE AIR MASS
WILL BE FROM THE PACIFIC WITH A ZONAL FLOW TAKING SHAPE. WE WILL SEE
ANOTHER SHOT OF COLDER AIR DROP DOWN BEGINNING ON TUESDAY AS A
SHALLOW COLD AIR MASS DROPS DOWN INTO THE AREA ON A FAIRLY
PERSISTENT FLOW FROM THE NNE. THIS FRONT WILL BRING A SMALL CHANCE
OF A FEW RAIN AND/OR SNOW SHOWERS. ONCE THE FRONT MOVES THROUGH, WE
STAY UNDER THE INFLUENCE OF COOL CANADIAN HIGH PRESSURE TO OUR WEST.
THE FLOW WILL REMAIN FROM THE NE, SO LAKE EFFECT IS NOT EXPECTED TO
BE A FACTOR.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1226 PM EST WED JAN 29 2025
LITTLE TO NO IMPACT EXPECTED AT ALL OF THE TERMINALS OVER THE NEXT
24 HOURS. CEILINGS HAVE GONE VFR AT OF OUR TERMINALS, WITH KAZO
AND KBTL EITHER HAVING SCATTERED OUT, OR WILL DO SO VERY SOON. THE
CLOUDS WILL THEN DIMINISH THROUGH EARLY THIS EVENING FROM SOUTH TO
NORTH. ONLY SOME HIGH CLOUDS WILL THEN REMAIN OVERNIGHT AND
THURSDAY.
WIND GUSTS FROM THE NW WILL CONTINUE UNTIL ALMOST SUNSET BEFORE
DIMINISHING. LIGHT WINDS WILL SWITCH OVERNIGHT TO BECOME FROM THE
SOUTH. WINDS WILL THEN BECOME GUSTY ONCE AGAIN TOWARD 17Z THURSDAY
TO AROUND 20-24 KNOTS AS BETTER DIURNAL MIXING TAKES PLACE.
GRR WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR
LMZ844>849.
DISCUSSION...NJJ
AVIATION...NJJ
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