725
FXUS63 KFGF 112026
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
326 PM CDT THU SEP 11 2025
KEY MESSAGES
- THERE IS A LEVEL 1 OUT OF 5 RISK FOR SEVERE STORMS IN
NORTHEAST ND INTO NORTHWEST MN TODAY INTO EARLY FRIDAY
MORNING. MOST LIKELY HAZARDS INCLUDE HAZARDS INCLUDE HAIL TO
THE SIZE OF PING PONG BALLS AND WIND GUSTS TO 60 MPH.
- AN ACTIVE PATTERN CONTINUES THIS WEEKEND INTO NEXT WEEK WITH
PERIODIC CHANCES FOR STORMS, SOME OF WHICH MAY BE SEVERE.
THERE IS ALSO A RISK FOR LOCALIZED FLASH FLOODING IMPACTS WITH
THIS UPCOMING PATTERN.
DISCUSSION
ISSUED AT 129 PM CDT THU SEP 11 2025
..SYNOPSIS
OBSERVATIONAL DATASETS AND ENSEMBLE GUIDANCE ILLUSTRATES HIGH
CONFIDENCE IN AN OMEGA BLOCK-TYPE PATTERN SETTING UP OVER THE
NORTHERN CONUS, WITH THE NORTHERN PLAINS INTO UPPER MIDWEST
REGION GENERALLY IN THE EXIT REGION OF THE UPSTREAM UPPER LOW.
THIS WOULD PROMOTE CONTINUED ACTIVE PATTERN WITH PERIODIC
CHANCES FOR SHOWERS AND THUNDERSTORMS, AS WELL AS ABOVE AVERAGE
TEMPERATURES THROUGH AT LEAST EARLY NEXT WEEK. INTO MID TO LATE
NEXT WEEK, ENSEMBLE GUIDANCE SUGGESTS THE OMEGA BLOCK PATTERN
STARTS TO BREAK DOWN, BUT WITH GENERALLY WEAK FLOW ALOFT AND/OR
QUASI-ZONAL FLOW ALOFT, SUGGESTING CONTINUATION OF ABOVE AVERAGE
TEMPERATURES OR TREND BACK TOWARD AVERAGE. COMPARED TO THIS
WEEKEND INTO EARLY NEXT WEEK, THIS WOULD TREND TOWARD SLIGHTLY
DRIER PATTERN MID TO LATE NEXT WEEK; HOWEVER, CONFIDENCE IN THIS
IS NOT HIGH DUE TO SPREAD WITHIN ENSEMBLE GUIDANCE ASSOCIATED
WITH SYNOPTIC PATTERN.
..SEVERE STORM RISK TODAY INTO EARLY FRIDAY MORNING
MARGINALLY-STRENGTHED LOW LEVEL JET LINGERS FROM THIS MORNING,
CONTINUING TO FEED SCATTERED THUNDERSTORMS EARLY THIS
AFTERNOON, AMID AROUND 35KT OF EFFECTIVE SHEAR AND 1000 J/KG OF
INSTABILITY. THIS WILL CONTINUE TO SUPPORT POTENTIAL FOR A FEW
STRONG TO SEVERE STORMS IN PORTIONS OF NORTHEAST NORTH DAKOTA
THIS AFTERNOON CAPABLE OF HAIL UP TO THE SIZE OF PING PONG
BALLS. THUNDERSTORMS REMAIN ELEVATED IN ALTITUDE, WITH A CLEAR
STABLE LAYER NEAR THE SURFACE MITIGATING THE POTENTIAL FOR
SEVERE WIND GUSTS AT THE SURFACE. THIS CURRENT LOW LEVEL JET IS
EXPECTED TO WANE MID AFTERNOON, BRINGING A BRIEF LULL IN STRONG
TO SEVERE STORM POTENTIAL THIS AFTERNOON.
ON CAVEAT TO THIS EXPECTATION OF "LULL" IS AN UNCERTAIN WINDOW
OF OPPORTUNITY OF SURFACE BASED THUNDERSTORMS IN CENTRAL NORTH
DAKOTA BETWEEN BISMARCK, JAMESTOWN AND COOPERSTOWN AREA THIS
AFTERNOON. CURRENTLY, SPC MESOANALYSIS SHOWS SURFACE CONVERGENCE
NEAR AN EFFECTIVE WARM FRONT, WITH ERODING INHIBITION AMONG
FILTERED SUNSHINE AND INCREASING LOW LEVEL MOISTURE. LENDING
SOME CREDENCE TO THIS SCENARIO IS TOWERING ALTOCUMULUS SOUTH OF
BISMARCK HINTING AT FORCING ALOFT FROM A SUBTLE MID LEVEL
IMPULSE. HOWEVER, MAIN UNCERTAINTY STEMS FROM WHETHER OR NOT
ENOUGH FORCING FOR LIFT WILL BE SUFFICIENT TO INITIATE
SUSTAINED THUNDERSTORMS IN THIS AREA.
SHOULD THUNDERSTORMS DEVELOP NEAR CENTRAL NORTH DAKOTA THIS
AFTERNOON, SUPERCELLS ARE THE EXPECTED STORM MODE GIVEN WIND
SHEAR IN EXCESS OF 35KT, SURFACE INSTABILITY AROUND 2000 J/KG.
LARGE HAIL EXCEEDING 2 INCHES AND LOCALLY GUSTY WINDS TO 70 MPH
WOULD BECOME LIKELY HAZARDS. RELATIVELY STRONG STORM RELATIVE
FLOW IN A CYCLONIC FASHION IN THE LOWEST 1 KM WILL ALSO ALLOW
FOR THE POTENTIAL FOR TORNADOES. WHILE THIS SCENARIO IS MORE
LIKELY INTO CENTRAL ND, THIS COULD EEK INTO OUR AREA OF THE
SHEYENNE RIVER VALLEY AND/OR SOUTHERN DEVILS LAKE BASIN.
REFERENCING THE 12Z REFS, THERE IS AROUND A 20% CHANCE OF THIS
SCENARIO TO OCCUR.
INTO THIS EVENING, A LOW LEVEL JET REINVIGORATES AFTER MIDNIGHT
TONIGHT. THIS RE-INVIGORATION WILL REIGNITE SCATTERED STORMS IN
PORTIONS OF NORTHEAST NORTH DAKOTA AGAIN, WITH GENERAL MOVEMENT
TOWARD THE EAST INTO NORTHWEST MINNESOTA EARLY FRIDAY MORNING.
INSTABILITY AND SHEAR PARAMETER SPACING LOOK VERY SIMILAR, WITH
SLIGHTLY MORE SHEAR TO WORK WITH PUSHING EFFECTIVE SHEAR AROUND
40KT. AGAIN, STORMS WILL BE ELEVATED IN ALTITUDE ATOP A
NIGHTTIME SURFACE STABLE LAYER. THIS AGAIN WOULD BRING HAIL UP
TO THE SIZE OF PING PONG BALLS AT THE FOREFRONT OF POTENTIAL
HAZARDS, BUT WOULDN'T DISCOUNT GUSTY WINDS TO 60 MPH SHOULD
STORMS MERGE INTO MORE LINEAR-TYPE COMPLEX WITHIN AN AREA OF
DCAPE OF AROUND 1000 J/KG AND LOW LEVEL JET ROOTED AROUND 925
MB.
..ACTIVE PATTERN CONTINUES INTO NEXT WEEK
WITH OUR AREA STUCK IN THE "STORMIER" PORTION OF THE OMEGA BLOCK
PATTERN JUST DOWNSTREAM OF THE WESTERN UPPER LOW, PERIODIC
CHANCES ALMOST DAILY TODAY THROUGH AT LEAST MONDAY IS FORECAST
IN PORTIONS OF OUR FORECAST AREA. WITH THE UPPER LOW TO OUR
WEST, LOCATIONS CLOSER TO CENTRAL NORTH DAKOTA HOLD A RELATIVELY
HIGHER CHANCE IN SEEING MORE INTERVALS OF THUNDERSTORMS COMPARED
TO ELSEWHERE INTO EASTERN NORTH DAKOTA AND MINNESOTA. MACHINE
LEARNING SEVERE WEATHER GUIDANCE HIGHLIGHT THE DAKOTAS INTO
MINNESOTA FOR LOW PROBABILITIES OF SEVERE STORMS FRIDAY THROUGH
AT LEAST MONDAY. SUNDAY INTO LATE MONDAY HOLD A RELATIVELY
HIGHER CHANCE COMPARED TO OTHER DAYS, COINCIDING WITH A
SHORTWAVE TROUGH ROUNDING THE EASTERN FLANKS OF THE UPPER LOW,
LENDING SLIGHTLY HIGHER CONFIDENCE IN SEVERE STORM POTENTIAL IN
OUR AREA LATE SUNDAY INTO EARLY MONDAY. IT REMAINS UNCLEAR TO
THE EXPECTED HAZARDS, ALTHOUGH THERE ARE NO SIGNALS FOR
SIGNIFICANT SEVERE POTENTIAL AT THIS TIME, KEEPING STRONG TO
SEVERE STORM POTENTIAL MORE ON THE LOWER END OF SEVERITY
SPECTRUM.
WITH PERSISTENT INTERVALS OF THUNDERSTORMS, AND AMPLE OVERALL
MOISTURE CONTENT AS WELL AS SUFFICIENT INSTABILITY INTO OUR AREA
FOR AN EXTENDED PERIOD OF TIME, LOCALIZED FLASH FLOODING IS ALSO
A POTENTIAL HAZARD THIS WEEKEND THROUGH EARLY NEXT WEEK.
CONFIDENCE IS NOT HIGH IN COVERAGE OR LOCATION OF THIS POTENTIAL
HAZARD, AND WILL LIKELY HINGE UPON MESOSCALE/STORM-SCALE
PROCESSES TO DRIVE THIS POTENTIAL - SOMETHING THAT WOULDN'T
LIKELY BE KNOWN UNTIL VERY NEAR THE EVENT (LESS THAN 24 HOURS).
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 129 PM CDT THU SEP 11 2025
MAIN IMPACT TO AVIATION THROUGH 18Z FRIDAY WILL COME FROM
THUNDERSTORMS.
SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE
REGION TODAY THROUGH TONIGHT INTO FRIDAY MORNING. -TSRA HAS BEEN
INCLUDED IN TAFS WITHIN THE NEAR TERM WHERE CONFIDENCE IS HIGH
ENOUGH IN THUNDERSTORM IMPACTS TO RESPECTIVE SITES, WITH VCTS
AFTER 06Z AT RESPECTIVE SITES HIGHLIGHTING CURRENTLY FAVORED
TIMEFRAME FOR THUNDERSTORMS TONIGHT INTO FRIDAY MORNING. IN
ADDITION TO LIGHTNING, STORMS MAY HOLD HAIL AND ERRATIC, GUSTY
WINDS, AS WELL AS BRIEF PERIODS OF LOWERED CEILINGS IN THE IFR
AND/OR MVFR CATEGORY.
WINDS WILL BE GENERALLY OUT OF THE SOUTH AND SOUTHEAST 10-15KT,
GUSTING TO 25KT OUTSIDE OF THUNDERSTORMS. WINDS MAY HOLD ON TO
GUSTS TONIGHT AT SOME LOCATIONS LIKE KFAR. THERE IS ALSO
EXPECTATION OF A LOW LEVEL JET TO DEVELOP BETWEEN 04Z-15Z,
ALTHOUGH IT REMAINS UNCLEAR IF IT WILL EXCEED 40KT TO INCLUDE IN
TAFS, AND REMAIN MORE IN THE 25-35KT RANGE ROOTED AROUND 5KFT.
FGF WATCHES/WARNINGS/ADVISORIES
ND...NONE.
MN...NONE.
DISCUSSION...CJ
AVIATION...CJ
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