611  
FXUS63 KFGF 020832  
AFDFGF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND FORKS ND  
332 AM CDT FRI JUN 2 2023  
   
SHORT TERM
 
(TODAY THROUGH SATURDAY)  
ISSUED AT 140 AM CDT FRI JUN 2 2023  
 
KEY MESSAGES...  
 
- SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ONCE AGAIN  
THIS AFTERNOON. THE PROBABILITY FOR BOTH SEVERE WEATHER AND  
FLASH FLOODING IS LOW BUT NON-ZERO.  
 
- HOT TEMPERATURES WILL CONTINUE WITH HIGH TEMPERATURES IN THE 90S  
TODAY AND SATURDAY.  
 
DISCUSSION....  
 
SURFACE ANALYSIS ACROSS THE NORTHERN PLAINS INDICATE NO REAL  
PROMINENT SURFACE FEATURES WITHIN THE VICINITY OF OUR CWA AT THIS  
TIME EXCEPT FOR SOME SUBTLE PRESSURE TROUGHS ACROSS NORTHEASTERN  
SOUTH DAKOTA, PRIMARILY ATTACHED TO THE SURFACE LOW OVER IN  
EASTERN WYOMING. LARGE SCALE RIDGING CONTINUES TO RETROGRADE  
TOWARDS OUR AREA FROM THE EAST PER WATER VAPOR SATELLITE.  
PERSISTENCE CONTINUES TO BE THE PRIMARY DRIVING FORCE FOR TODAYS  
FORECAST. HIGH TEMPERATURES THIS AFTERNOON SHOULD BE A FEW DEGREES  
COOLER THAN TODAY THANKS TO 2 C LOWER 850MB TEMPERATURES AND VERY  
LOW CONVECTIVE TEMPERATURES. REGARDLESS OF COOLER TEMPERATURES,  
EXPECT AT LEAST 88 TODAY, WITH THE RED RIVER VALLEY EXCEEDING 90.  
 
SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR ONCE AGAIN THIS  
AFTERNOON THANKS TO LOW CONVECTIVE TEMPERATURES AND STRONG  
BOUNDARY LAYER HEATING. THE STRONGEST SHOWERS AND THUNDERSTORMS  
WILL HAVE THE POTENTIAL TO PRODUCE ISOLATED SEVERE STORMS AND  
ISOLATED FLASH FLOODING.  
 
FOR THE SEVERE THREAT, MLCAPE VALUES HAVE TENDED TO APPROACH  
1500-2500 J/KG THROUGH THE LAST FEW DAYS. WITH A SIMILAR AIRMASS OVER  
US, THAT APPEARS TO BE THE MOST LIKELY SOLUTION ONCE AGAIN DESPITE  
SOME CAMS CONTINUING TO UNDERESTIMATE MLCAPE. MID-LEVEL LAPSE  
RATES CONTINUE TO BE MOSTLY CONDITIONALLY UNSTABLE TO NEAR STABLE, SO  
MOST OF THE INSTABILITY WILL COME FROM WITHIN THE MIXED LAYER.  
COMBINE THAT WITH VERY WEAK FLOW ALOFT, RESIDENCE TIME WITHIN THE  
HAIL GROWTH ZONE MAY BE EXTENDED JUST ENOUGH TO PRODUCE UP TO  
QUARTER SIZE HAIL. WITH THE LACK OF EFFECTIVE BULK SHEAR TO REALLY  
DEVELOP ANY MEANINGFUL MESOCYCLONES (OUTSIDE A RANDOM OUTFLOW  
BOUNDARY DEVELOPING PRODUCING A STORM SCALE ENVIRONMENT FOR  
SUPERCELLS), THE STRONGEST SEVERE STORMS COULD PRODUCE UP TO  
QUARTER SIZE HAIL, AND THIS WOULD BE A VERY ISOLATED THREAT.  
ADDITIONALLY, WITH THE DEEP VERTICAL MIXING AND THE HIGH  
PRECIPITABLE WATER VALUES, DOWNBURST WINDS APPEAR POSSIBLE DUE TO  
ENHANCED WATER LOADING DESPITE DCAPE VALUES GENERALLY BEING IN THE  
700-1100 RANGE. WHILE NOT A SLAM DUNK BY ANY MEANS, THERE IS THAT  
POTENTIAL ONCE AGAIN.  
 
AS STATED ABOVE, FLASH FLOODING MAY CONTINUE TO POSE A RISK TODAY.  
HIGH PW VALUES APPROACHING THE 95TH PERCENTILE AND HIGHER WILL  
CONTINUE TO LINGER ACROSS THE AREA THANKS TO CONTINUED SOUTHERLY  
FLOW. EFFICIENT RAINFALL RATES ARE LIKELY TO CONTINUE, WITH RATES  
POTENTIALLY EXCEEDING AN INCH PER HOUR AT TIMES, ALTHOUGH THE  
RESIDENCE TIME AT ANY PARTICULAR POINT IS VERY UNCERTAIN AND HAS A  
VERY LOW PROBABILITY FOR STICKING AROUND LONG ENOUGH AT ANY ONE  
SITE TO PRODUCE SIGNIFICANT RAINFALL ACCUMULATIONS. REGARDLESS,  
HEAVY RAINFALL RATES MAY POSE ISOLATED FLASH FLOODING RISK AS  
MOTION OF THESE STORMS WILL BE FAIRLY MINIMAL AND RESIDENCE TIME  
WILL GENERALLY BE AT THE MERCY OF THE ORDINARY THUNDERSTORM LIFE  
CYCLE.  
 
FOR SATURDAY, EXPECT MORE OF THE SAME, WITH HIGH TEMPERATURES  
APPROACHING THE 90S AND SCATTERED SHOWERS AND THUNDERSTORMS. AS  
THE RIDGE CONTINUES TO PUSH SLOWLY WESTWARD, THE SPATIAL EXTENT OF  
SHOWERS AND STORMS MAY BECOME LESS AND LESS, ALTHOUGH CONFIDENCE  
IS TOO LOW TO SAY THAT WITH ANY CERTAINTY. FOR NOW JUST EXPECT  
CONTINUED CHANCES FOR SHOWERS AND STORMS WITH ISOLATED STRONG TO  
SEVERE STORMS POSSIBLE.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 140 AM CDT FRI JUN 2 2023  
 
-ABOVE AVERAGE TEMPERATURES CONTINUE SUNDAY INTO MONDAY, WITH A  
PATTERN SHIFT THAT MAY ALLOW FOR TEMPERATURES TO BE MORE IN LINE  
WITH SEASONAL RANGES.  
 
-THERE CONTINUES TO BE CONDITIONAL RISK FOR ISOLATED STRONG TO  
SEVERE THUNDERSTORMS DURING THE AFTERNOON AND EVENING PERIODS SUNDAY  
INTO MONDAY. UNSETTLED PATTERN CONTINUES THROUGH THE END OF NEXT  
WEEK, HOWEVER THE PROBABILITY FOR SEVERE IS LOWER.  
 
LARGE SCALE RIDGE IS STILL SHOWN TO BE IN PLACE OVER OUR CWA SUNDAY  
INTO MONDAY BEFORE FINALLY SHIFTING WEST WHILE TROUGHING DEEPENS  
OVER HUDSON BAY. DUE TO THE INFLUENCE OF THE RIDGE WE SEE SIMILAR  
CONDITIONS AND CONCERNS AS THE PREVIOUS DAYS WILL WELL ABOVE AVERAGE  
TEMPERATURES AROUND 90, AND DIURNALLY FOCUSED THUNDERSTORM ACTIVITY  
(PRIMARILY DRIVEN BY CONVECTIVE TEMPS, MODEST INSTABILTY AND WEAK  
SURFACE CONVERGENCE). THE PREDICTABILITY OF ACTUAL COVERAGE/IMPACTS  
IS LOW DUE TO THE LACK OF SYNOPTIC/ORGANIZED FORCING, BUT AS WITH  
PREVIOUS DAYS WE SHOULD HAVE DAILY AFTERNOON/EVENING RISKS FOR A FEW  
STRONG OR SEVERE STORMS (ML CAPE STILL IN THE 1500-2500 J/KG WITH  
LOW SHEAR). HAIL AROUND 1 INCH, LIMITED MICROBURST POTENTIAL (GUSTS  
AROUND 60 MPH), AND LOCALIZED HEAVY/EXCESSIVE RAIN RISK (DUE TO HIGH  
PWATS).  
 
AS THE RIDGE TRANSITIONS WEST TUESDAY INTO THE LATER PART OF NEXT  
WEEK, THE INFLUENCE WANES AND WE SEE NORTHERLY FLOW START TO BUILD  
BACK INTO OUR CWA, WITH CLUSTERS SHOWING SOME SEPARATION IN THE  
DEPTH OF MID LEVEL TROUGHING TO THE NORTHEAST THAT WOULD INFLUENCE  
THE DEGREE OF CAA AND FORCING DUE TO ANY PROGRESSIVE MID LEVEL  
SHORTWAVES WITHIN THE NORTHERLY FLOW. THIS CREATES LARGER UNCERTAINTY  
ON TEMPERATURES, BUT ALSO ON IMPACTS/COVERAGE OF STORMS. THESE  
PROGRESSIVE FEATURES ALLOW FOR MORE ORGANIZED FORCING "WHEN" THE  
PASS, BUT THERE IS LARGER SPREAD ON DETAILS. THIS LARGE SCALE  
PATTERN WILL ALSO TEND TO TRANSLATE TO THE BL WITH DRIER FLOW ACROSS  
MUCH OF OUR CWA LOWERING POTENTIAL INSTABILTY OR AT LEAST CREATING A  
LARGE GRADIENT WEST TO EAST (HIGHER INSTABILTY/PWATS WEST TO LOWER  
IN THE EAST).  
 
IF THAT MOIST/UNSTABLE AIR MASS REMAIN OVER PARTS OF OUR CWA WHEN  
THOSE SHORTWAVES ARRIVE THERE MAY BE ORGANIZED PERIODS OF SEVERE  
(NOT CURRENTLY SHOWN BY MACHINE LEARNING/ANALOGUES). IF THAT AXIS IS  
WEST THEN WE WOULD ONLY BE LOOKING AT PERIODS OF SHOWERS AND NON  
SEVERE STORMS WHEN THEY PASS.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)  
ISSUED AT 1133 PM CDT THU JUN 1 2023  
 
VFR CONDITIONS NOW AND THROUGHOUT THE PERIOD AS CONVECTION  
DISSIPATES. HIGH CLOUDS THROUGH MOST OF THE OVERNIGHT AND INTO  
TOMORROW. WINDS WILL BE MOSTLY FROM THE SOUTHEAST IN THE 5 TO 12  
KT RANGE.  
 

 
   
FGF WATCHES/WARNINGS/ADVISORIES
 
 
ND...NONE.  
MN...NONE.  

 
 

 
 
SHORT TERM...PERROUX  
LONG TERM...DJR  
AVIATION...JR  
 
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