034
FXUS63 KFGF 130331
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1031 PM CDT TUE AUG 12 2025
KEY MESSAGES
- THERE IS POTENTIAL FOR STRONG TO SEVERE STORMS MID TO LATE
THIS WEEK, INCLUDING A 2 OUT OF 5 RISK FOR SEVERE
THUNDERSTORMS THURSDAY AFTERNOON AND EVENING.
UPDATE
ISSUED AT 1031 PM CDT TUE AUG 12 2025
NO FORECAST CHANGES... SMOKE REMAINS AS EVIDENT BY THE GFK OBS
STILL SHOWING HZ SINCE THE OBSERVER LEFT AND THE UND WEBCAM
STILL LOOKING SEMI FOGGY ALMOST AS SMOKE BEGINS TO SETTLE CLOSER
TO THE SFC WITH THE DEVELOPING OVERNIGHT INVERSION.
UPDATE
ISSUED AT 607 PM CDT TUE AUG 12 2025
SHOWER ACTIVITY HAS MOSTLY CEASED ACROSS THE LOW REGION WITH
WINDS BECOMING CALM IN THE NEXT FEW HOURS. WHILE SMOKE IS BEING
REPORTED AT NUMEROUS STATIONS ACROSS THE REGION A LACK A
VISIBILITY IMPACTS IS SHOWING THAT IT MAY BE THINNER THAN
ORIGINALLY EXPECTED. REGARDLESS AN AQA REMAINS IN EFFECT FOR
NORTHWEST MINNESOTA THROUGH WEDNESDAY EVENING.
DISCUSSION
ISSUED AT 325 PM CDT TUE AUG 12 2025
..SYNOPSIS
WATER VAPOR SATELLITE IMAGERY THIS AFTERNOON DEPICTS AN UPPER TROUGH
IN NORTHERN ON INTO MN, WITH SUBSIDENT RIDGING JUST UPSTREAM WITHIN
SK/MB INTO THE DAKOTAS. THIS IS HELPING STREAM IN ADDITIONAL NEAR-
SURFACE SMOKE, ALTHOUGH CONCENTRATIONS ARE CURRENTLY NOT AS DENSE AS
WHAT SMOKE GUIDANCE DEPICTED THIS MORNING, KEEPING AQI'S IN THE
YELLOW TO ORANGE CATEGORIES. COLD TEMPERATURES ALOFT NEARER TO THE
AXIS OF THE UPPER TROUGH ARE ALLOWING FOR SHOWERS AND WEAK
THUNDERSTORMS NEAR LAKE OF THE WOODS IN NORTHWEST MN. THIS WILL
CONTINUE THROUGH THE AFTERNOON, THE MAIN HAZARD WILL BE LIGHTNING.
ENSEMBLE GUIDANCE INDICATES UPSTREAM RIDGING WILL BUILD FURTHER OVER
THE NORTHERN PLAINS DOWNSTREAM OF AN UPPER SHORTWAVE TROUGH
IMPINGING UPON THE NORTHERN ROCKIES, REINTRODUCING ZONAL TO SLIGHTLY
SOUTHWESTERLY FLOW ALOFT OVER THE DAKOTAS INTO MINNESOTA. THIS WILL
PROMOTE THE RETURN OF MOISTURE AND WARMTH BACK INTO THE NORTHERN
PLAINS AND UPPER MIDWEST STARTING WEDNESDAY. THIS COMBINED WITH
STEEP LAPSE RATES ALOFT OVERSPREADING THIS SAME REGIONS ALONG WITH
INCREASED FLOW ALOFT WILL CONTRIBUTE TO POTENTIAL STRONG TO SEVERE
STORMS AS EARLY AS WEDNESDAY OVERNIGHT/EARLY THURSDAY MORNING,
POTENTIALLY LASTING INTO FRIDAY OR EVEN SATURDAY.
..STRONG TO SEVERE STORMS MID TO LATE THIS WEEK
AS THE AFOREMENTIONED WAVE OUT OF THE NORTHERN ROCKIES MOVES INTO
SOUTH-CENTRAL CANADA, UPPER FORCING FOR ASCENT INCREASES OVER THE
NORTHERN PLAINS AND UPPER MIDWEST, HELPING PUSH A COLD FRONT THROUGH
THE REGION. WHILE THIS, COMBINED WITH INCREASING INSTABILITY
POTENTIALLY GREATER THAN 3000 J/KG AND EFFECTIVE SHEAR ON THE ORDER
OF 30-45KT IS DRIVING THE SEVERE STORM POTENTIAL, THERE ARE
IMPORTANT DETAILS THAT REMAIN UNCERTAIN. UNCERTAINTIES ARE MAINLY
TIED TO THE RELATIONSHIP BETWEEN THE DEGREE OF FORCING AND
CONVECTIVE INHIBITION LOWERS CONFIDENCE IN STORM EVOLUTION,
PARTICULARLY THURSDAY AND FRIDAY.
ENSEMBLE GUIDANCE DEPICTS A COLD FRONT TO MOVING THROUGH THE
MAJORITY OF OUR AREA THURSDAY. HOWEVER, THE BEST UPPER FORCING FOR
ASCENT SHOULD REMAIN WITHIN CANADA RELATIVE TO OUR AREA. THERE IS
POTENTIAL FOR SUBTLE, LOW AMPLITUDE IMPULSES TO MOVE OVER THE
DAKOTAS THROUGH THE BASE OF THE UPPER TROUGH IN CANADA, WHICH MAY
PROVIDE ENOUGH SUPPORT (ALONG WITH ENHANCING CONVERGENCE IN THE
LOWER LEVELS/NEAR THE FRONT) TO OVERCOME CAPPING. ADDITIONALLY,
DEGREE OF CAPPING REMAINS IN QUESTION (COULD BE MODERATELY STRONG TO
VERY STRONG). THIS OPENS UP A RANGE OF POSSIBLE OUTCOMES RANGING
FROM DISCRETE SUPERCELLS ALONG THE COLD FRONT CAPABLE OF ALL
HAZARDS, OR MORE CLUSTERS OF STORMS EVENTUALLY GROWING MORE LINEAR
PLACING HIGH WIND AND HAIL IN THE FOREFRONT OF MOST LIKELY HAZARDS.
THE EVOLUTION OF CONVECTION AS WELL AS FRONTAL PLACEMENT WILL
DICTATE FRIDAY'S SEVERE STORM POTENTIAL. SHOULD THE FRONT BE SLOW TO
MOVE THROUGH THE AREA, IT COULD STALL NEAR THE TRI-STATE AREA OF THE
DAKOTAS AND MINNESOTA. THIS WOULD ALLOW SEVERE STORMS TO DEVELOP
NEAR THE STALLED FRONT AND PERHAPS EVENTUAL SURFACE CYCLOGENESIS
NEAR THE SAME AREA. SHOULD THIS OCCUR, ALL HAZARDS WOULD AGAIN BE
POSSIBLE. GIVEN THE POSSIBILITY OF STRONG INSTABILITY COUPLED WITH
MODERATE SHEAR, AS WELL AS STRONG DOWNDRAFT ENHANCEMENT/MAINTENANCE,
SIGNIFICANT SEVERE HAZARDS ARE POSSIBLE BOTH THURSDAY AND FRIDAY
THOUGH THIS REMAINS A LOW CONFIDENCE SCENARIO.
IT IS ALSO WORTH MENTIONING POTENTIAL FOR STRONG STORMS LATE
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING FROM ELEVATED
CONVECTION, ALTHOUGH THE CURRENTLY FAVORED LOCATION FOR NOCTURNAL
CONVECTION REMAINS IN SOUTH DAKOTA. SHOULD STORMS MAKE THEIR WAY
INTO OUR AREAS LIKE SOUTHEAST ND INTO WEST-CENTRAL MN, HAIL AND
GUSTY WINDS WOULD BE MAIN HAZARDS.
AVIATION /03Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1031 PM CDT TUE AUG 12 2025
VFR WITH A LOW CONFIDENCE CHANCE FOR MVFR CONDITIONS ARE
FORECAST AT TAF SITES THROUGH WEDNESDAY NIGHT. WILDFIRE SMOKE
NEAR THE SURFACE, WHICH COULD REDUCE VISIBILITY AS LOW AS 4SM
SHOULD THE INVERSION TRAP IT NEAR THE SFC, IS THE MAIN
CONTRIBUTOR TO MVFR POTENTIAL. CLEAR SKIES TONIGHT (ASIDE FROM
THE SMOKE) AND CALM WINDS BEFORE PICKING UP LATE WEDNESDAY
MORNING FROM THE SOUTHEAST WITH GUSTS UP TO 25 KTS IN THE DVL
AREA WED AFTERNOON. SUSTAINED WINDS OF 15KTS OR SO IN THE DVL
OTHERWISE SE AT 5-10 KTS FOR OTHER SITES
FGF WATCHES/WARNINGS/ADVISORIES
ND...NONE.
MN...NONE.
UPDATE...TT
DISCUSSION...CJ
AVIATION...TT
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