736  
FXUS63 KBIS 221117  
AFDBIS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BISMARCK ND  
617 AM CDT FRI JUN 22 2018  
   
UPDATE
 
 
ISSUED AT 615 AM CDT FRI JUN 22 2018  
 
THE FORECAST REMAINS ON TRACK. BLENDED LATEST OBSERVATIONS WITH  
NEAR TERM TRENDS EARLY THIS MORNING.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
 
ISSUED AT 318 AM CDT FRI JUN 22 2018  
 
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE SHOWER AND  
THUNDERSTORM CHANCES TODAY AND TONIGHT.  
 
CURRENTLY, S/WV TROUGH OVER CENTRAL MONTANA SLOWLY PUSHING EAST  
EARLY THIS MORNING. ASSOCIATED SFC TROUGH WELL TO OUR WEST, WHICH  
HAS CONFINED THE BEST INSTABILITY OVER MONTANA THIS PAST EVENING.  
SHOWERS HAVE MOVED INTO SOUTHWEST ND SINCE 06Z, ALONG WITH A FEW  
LIGHTNING STRIKES. MUCAPE IS ALMOST NON-EXISTENT ACROSS SOUTHWEST  
ND, SO PREDICTABLY THE CONVECTION HAS WEAKENED AS IT MOVED INTO  
MY SOUTHWEST THE PAST FEW HOURS.  
 
S/WV TROUGH CONTINUES EAST TODAY AND TONIGHT INTO THE DAKOTAS,  
ALONG WITH THE SFC TROUGH MOVING INTO THE WESTERN DAKOTAS.  
CONTINUED BOUNDARY LAYER MOISTURE ADVECTION COUPLED WITH DAYTIME  
HEATING WILL SEE INCREASING INSTABILITY ACROSS ALL OF WESTERN AND  
CENTRAL ND TODAY. COMBINATION OF THE INSTABILITY AND FORCING WILL  
SEE SCATTERED SHOWERS AND THUNDERSTORMS THIS PERIOD, WITH THE MAIN  
WINDOW THIS AFTERNOON AND EVENING. SHEAR PARAMETERS ARE WEAK SO  
THE THREAT FOR SEVERE WEATHER REMAINS LOW. IF WE SEE ANY PULSE  
SEVERE TYPE STORMS WE WOULD EXPECT THEM OVER THE WEST ALONG THE  
FRONTAL BOUNDARY WHERE FORCING WILL BE GREATEST. THIS IS ALSO  
WHERE SPC DREW IN A MARGINAL RISK. BUT AGAIN, THE THREAT WILL BE  
LOW AND ONLY MARGINALLY SEVERE HAIL AT MOST WOULD BE EXPECTED.  
   
LONG TERM
 
(SATURDAY THROUGH THURSDAY)  
 
ISSUED AT 318 AM CDT FRI JUN 22 2018  
 
AN ACTIVE PATTERN REMAINS OVER THE NORTHERN PLAINS THROUGH THE  
WEEKEND AND INTO EARLY NEXT WEEK, AS AN UPPER LEVEL LOW MOVES FROM  
THE MONTANA ROCKIES ON SATURDAY SOUTHEAST INTO THE CENTRAL PLAINS  
BY SUNDAY NIGHT INTO MONDAY. A SERIES OF EMBEDDED S/WVS WILL BE  
MOVED THROUGH THE LOCAL REGION AS THE UPPER LOW MIGRATES SLOWLY TO  
THE SOUTHEAST, TRIGGERING SHOWERS AND THUNDERSTORMS. WITH ROBUST  
BOUNDARY LAYER MOISTURE WE WILL SEE DIURNAL INSTABILITY EACH DAY  
SATURDAY THROUGH MONDAY, AS WELL AS SOME MUCAPE DURING THE  
NIGHTTIME HOURS. BULK SHEAR REMAINS VERY WEAK SO THE OVERALL  
THREAT FOR SEVERE WEATHER WILL REMAIN LOW, BUT CANNOT DISCOUNT A  
FEW PULSE-SEVERE STORMS. THE WEAK FLOW ALOFT WILL INCREASE THE  
POTENTIAL FOR HEAVY RAIN PRODUCERS FOR ANY STORMS THAT DEVELOP.  
 
THE UPPER LOW KICKS OFF TO THE EAST BY TUESDAY, FOLLOWED BY A  
FRONTAL PASSAGE LATER ON TUESDAY AND INTO TUESDAY NIGHT AS ANOTHER  
UPPER LOW MOVES EAST ACROSS SOUTH CENTRAL CANADA. THIS FROPA WILL  
ALSO BRING A CHANCE FOR SHOWERS AND T-STORMS.  
 
ZONAL FLOW ALOFT THEN SETS UP FOR THURSDAY, AHEAD OF A DEVELOPING  
TROUGH OVER THE PACIFIC NORTHWEST.  
 
TEMPERATURES OVERALL THROUGH THE LONG TERM PERIOD WILL REMAIN  
SEASONAL FOR LATE JUNE.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)  
 
ISSUED AT 615 AM CDT FRI JUN 22 2018  
 
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS WESTERN  
NORTH DAKOTA TODAY, WITH AN ISOLATED THREAT EXPANDING ACROSS THE  
CENTRAL IN THE AFTERNOON AND EVENING. VFR CONDITIONS OUTSIDE OF  
RAIN SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS WESTERN AND  
CENTRAL NORTH DAKOTA FOR THE 12Z FORECAST PERIOD. THERE IS SOME  
HINT OF LOW STRATUS DEVELOPMENT ACROSS PORTIONS OF WESTERN AND  
CENTRAL ND LATE FRIDAY NIGHT.  
 

 
   
BIS WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
UPDATE...NH  
SHORT TERM...NH  
LONG TERM...NH  
AVIATION...NH  
 
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