755
FXUS63 KFGF 220435
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1135 PM CDT MON APR 21 2025
KEY MESSAGES
- A PERIOD OF RAIN SHOWERS WILL MOVE THROUGH THE REGION LATE
TONIGHT THROUGH TUESDAY, ENDING BY MIDDAY IN THE CENTRAL AND
SOUTHERN RED RIVER VALLEY AND LINGERING NORTH OF HIGHWAY 2
THROUGH THE AFTERNOON.
- THERE ARE ADDITIONAL RAIN CHANCES THURSDAY MAINLY ALONG AND
SOUTH OF I-94 AND ACROSS THE REGION EARLY NEXT WEEK.
UPDATE
ISSUED AT 1135 PM CDT MON APR 21 2025
RAIN IS SLOWLY MOVING INTO PORTIONS OF EASTERN NORTH DAKOTA
TONIGHT, WITH LIGHT RAIN NOW BEING REPORTED AT OAKES AND DEVILS
LAKE. THIS WILL CONTINUE TO OVERSPREAD THE REMAINDER OF EASTERN
NORTH DAKOTA, WEST CENTRAL MINNESOTA, AND THE RED RIVER VALLEY
OVER THE NEXT COUPLE HOURS, THEN INTO NORTHWEST MINNESOTA BY
EARLY TUESDAY MORNING. THE FORECAST REMAINS ON TRACK THIS
EVENING.
UPDATE
ISSUED AT 616 PM CDT MON APR 21 2025
THE FORECAST REMAINS ON TRACK THIS EVENING WITH WINDS RANGING
FROM 10 TO 15 MPH AND OCCASIONAL GUSTS TO 20 MPH. TEMPERATURES
ARE IN THE UPPER 50S TO MIDDLE 60S. RAIN IS STILL WELL TO THE
WEST OF THE AREA, BUT SLOWLY PROGRESSING EASTWARD. NO
ADJUSTMENTS TO TIMING WERE MADE AT THIS TIME, BUT WILL CONTINUE
TO ASSESS THE ONSET TIMING OF TONIGHT'S RAIN ACTIVITY.
DISCUSSION
ISSUED AT 307 PM CDT MON APR 21 2025
..SYNOPSIS
SHORTWAVE RIDGING IN PLACE ALOFT OVER OUR AREA BETWEEN THE STRONGER
MID/UPPER LOW OVER THE GREAT LAKES AND AN SHORTWAVE TROUGH BUILDING
UPSTREAM OUT OF MONTANA. THIS UPSTREAM TROUGH BRINGS OUR NEXT ROUND
OF RAIN TONIGHT INTO TUESDAY. THIS IS FOLLOWED BY A TRANSITION BACK
TO A SPLIT SOUTHWEST FLOW PATTERN THAT BRINGS ANOTHER WEAKER MID
LEVEL TROUGH THROUGH THE REGION WEDNESDAY NIGHT-THURSDAY, THEN
DEEPER SOUTHWEST FLOW AS A LARGER SCALE TROUGH DEVELOPS LATE NEXT
WEEKEND IN TO EARLY NEXT WEEK. THOSE FEATURES BRING OUR NEXT
RAINFALL CHANCES, THOUGH DETAILS ARE MORE UNCERTAIN. THE TENDENCY
WILL BE FOR TEMPERATURES TO REMAIN ABOVE AVERAGE (THOUGH NOT
UNSEASONABLE/ANOMALOUS IN NATURE).
..RAIN LATE TONIGHT-TUESDAY
THE INITIAL AXIS OF RAIN SHOWERS ARRIVES WITH AN AXIS OF WAA LOFT
AHEAD OF THE 700MB TROUGH LATE THIS EVENING IN OUR WEST, THEN
ROTATES THROUGH OUR CWA AS THE 700 MB LOW DEEPENS TUESDAY. INITIALLY
MID LEVEL LAPSE RATES MAY BE STEEP ENOUGH TO SUPPORT SOME CAPE IN
OUR FAR WEST-SOUTHWEST AND ISOLATED LIGHTNING ACTIVITY TONIGHT. RAIN
SHOULD END SOONER IN OUR SOUTH TUESDAY BASED ON HREF/NBM, BUT COULD
LINGER LONGER INTO THE AFTERNOON/EVENING NORTH OF HIGHWAY 2 WHERE A
STALL BAROCLINIC ZONE SETS UP AS THE TROUGH SHIFTS NORTH THEN EAST
THROUGH TUESDAY NIGHT. THE MAIN IMPACTS WILL BE WIDESPREAD LIGHT
RAIN (0.25" OR LESS), WITH A CHANCE FOR GREATER THAN 0.5" (40% BASED
ON HREF AND NBM PROBS). THE BEST CHANCE FOR THOSE HIGHER AMOUNTS
BASED ON ENSEMBLES IS TOWARDS THE DEVILS LAKE BASIN CLOSER TO WHERE
THE PIVOT OF THE 700 MB LOW IS SHOWN TO TRACK, THOUGH POCKETS OF
0.25-0.5" COULD STILL OCCUR JUST DO TO THE CONVECTIVE NATURE OF THE
RAINFALL.
..RAIN CHANCES MIDWEEK AND EARLY NEXT WEEK
A WEAKER/POSITIVELY TITLED 700MB TROUGH ROTATES THROUGH WEST-
SOUTHWEST FLOW WEDNESDAY NIGHT INTO THURSDAY, WITH THE BEST SIGNAL
FOR RAINFALL DEPENDS ON LOCATION OF A BAROCLINIC ZONE/THETA-E AXIS
AS PVA ROTATES THOUGH THE MEAN FLOW. CLUSTERS SHOW QUITE A BIT OF
SPREAD NOW AND MORE COMMON SCENARIOS SHIFTING THIS FARTHER SOUTH AND
LOWERING PROBABILITIES IN THE MAJORITY OF OUR CWA (PROBABILITY FOR
0.5" IS NOW ONLY 15% IN OUR FAR SOUTH).
THERE IS A MUCH BETTER SYNOPTIC SIGNAL FOR RAIN LATER IN THE
WEEKEND/EARLY NEXT WEEK AS A LARGER TROUGH BUILDS OVER THE WESTERN
US. THE GENERAL PATTERN IS SHOWING STRONG CONSISTENCY, HOWEVER
DETAILS REGARDING THE EVOLUTION OF MID/UPPER LOW AND TRACK WILL
DETERMINE POTENTIAL RAIN AMOUNTS, COMPLICATED BY THE STANDARD
CONVECTIVE NATURE OF THE LIKELY RAINFALLS. INSTABILITY ISN'T
CURRENTLY SHOWN TO BE HIGH ENOUGH TO RAISE IMMEDIATE CONCERNS
REGARDING SEVERE POTENTIAL (GEFS BASED MACHINE LEARNING PROBS ALSO
DO NOT SUPPORT THAT). HOWEVER, IT COULD BE ENOUGH TO SUPPORT LOCALLY
HEAVY RAINFALL AS THE EVENT UNFOLDS. THE PROBABILITY FOR GREATER THAN
0.5" OF RAINFALL AT THIS RANGE IS IN THE 20-40% RANGE FOR THAT
SYSTEM.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1135 PM CDT MON APR 21 2025
VFR CONDITIONS PREVAIL AT ALL SITES, WITH CEILINGS EXPECTED TO
FALL TO MVFR AND POSSIBLY IFR LEVELS OVERNIGHT. RAIN WILL
CONTINUE TO OVERSPREAD THE AREA, WITH KDVL ALREADY REPORTING
SHOWERS OFF AND ON. WINDS REMAIN OUT OF THE SOUTH THROUGH MUCH
OF THE OVERNIGHT PERIOD BEFORE SHIFTING TO THE SOUTHWEST ON
TUESDAY AS RAIN COMES TO AN END FROM SOUTHWEST TO NORTHEAST.
WINDS WILL BRIEFLY INCREASE AS THE SHIFT OCCURS, WITH A FEW
GUSTS UP TO 25 KNOTS POSSIBLE.
FGF WATCHES/WARNINGS/ADVISORIES
ND...NONE.
MN...NONE.
UPDATE...LYNCH
DISCUSSION...DJR
AVIATION...LYNCH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page