996
FXUS63 KFGF 122107
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
407 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 INTO 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 AXIS OF THE UPPER TROUGH ARE
ALLOWING FOR SHOWERS AND WEAK THUNDERSTORMS NEAR LAKE OF THE
WOODS AREA IN NORTHWEST MN. THIS WILL CONTINUE THROUGH THE
AFTERNOON, 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 RETURN OF MOISTURE AND WARMTH BACK
INTO THE NORTHERN PLAINS AND UPPER MIDWEST STARTING WEDNESDAY.
THIS COMBINE 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. MORE DETAILS ON THIS FOUND BELOW.
..STRONG TO SEVERE STORMS MID TO LATE THIS WEEK
AS THE AFOREMENTIONED WAVE OUT OF THE NORTHER 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 DEGREE
OF FORCING AND CONVECTIVE INHIBITION LOWERS CONFIDENCE IN STORM
EVOLUTION, PARTICULARLY THURSDAY AND FRIDAY.
ENSEMBLE SUITE OF GUIDANCE AGREES ON A COLD FRONT TO MOVE
THROUGH MAJORITY OF OUR AREA THURSDAY. HOWEVER, 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 TOWARD 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 TURNING INTO MORE LINEAR FEATURE 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 STORM
TO DEVELOP NEAR THIS 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.
IT IS ALSO WORTH MENTIONING POTENTIAL FOR STRONG STORMS LATE
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING FROM ELEVATED
CONVECTION, ALTHOUGH 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 /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 115 PM CDT TUE AUG 12 2025
VFR WITH PERIODIC MVFR CONDITIONS ARE FORECAST AT TAF SITES
THROUGH WEDNESDAY MORNING. WILDFIRE SMOKE NEAR THE SURFACE
REDUCING VISIBILITY AS LOW AS 3SM IS THE MAIN CONTRIBUTOR TO
MVFR CONDITIONS. SMOKE IS FORECAST TO SWEEP THROUGH THE AREA
STARTING THIS AFTERNOON INTO EARLY EVENING, LASTING UNTIL EARLY
WEDNESDAY MORNING.
OTHERWISE, NORTHWEST WINDS 10-15KT, GUSTS TO 23KT, WILL PERSIST
UNTIL AROUND 01Z BEFORE LESSENING BELOW 10KT. AFTERNOON CUMULUS
WILL LEAD TO SCATTERED DECK BETWEEN 3 TO 5 KFT, MORE BROKEN DECK
NEAR THE INTERNATIONAL BORDER. WITHIN NORTHWEST MINNESOTA,
SCATTERED SHOWERS AND ISOLATED WEAK THUNDERSTORMS WILL DEVELOP
THIS AFTERNOON, MAINLY NEAR LAKE OF THE WOODS AREA. THIS
ACTIVITY WILL NOT IMPACT TAF SITES.
FGF WATCHES/WARNINGS/ADVISORIES
ND...NONE.
MN...NONE.
DISCUSSION...CJ
AVIATION...CJ
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