314  
ACUS48 KWNS 030851  
SWOD48  
SPC AC 030850  
 
DAY 4-8 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0350 AM CDT WED JUN 03 2020  
 
VALID 061200Z - 111200Z  
   
..DISCUSSION
 
   
..DAY 4/SAT - EASTERN MT INTO WESTERN ND/SD
 
 
AN INTENSE SHORTWAVE IMPULSE EMBEDDED IN THE LARGER-SCALE WESTERN  
UPPER TROUGH WILL EJECT NORTH/NORTHEAST FROM THE FOUR CORNERS  
VICINITY TO THE NORTHERN HIGH PLAINS ON SATURDAY. IN RESPONSE, A  
SURFACE LOW WILL DEEPEN OVER MT WITH A SURFACE TROUGH EXTENDING INTO  
THE NORTHERN AND CENTRAL HIGH PLAINS. STRONG SOUTH/SOUTHEASTERLY LOW  
LEVEL FLOW WILL TRANSPORT A SWATH OF RICHER BOUNDARY-LAYER MOISTURE  
NORTHWEST ACROSS PARTS OF THE WESTERN DAKOTAS AND EASTERN/CENTRAL  
MT. STRONG VERTICAL SHEAR WILL OVERLAP WITH STEEP MIDLEVEL LAPSE  
RATES AND MODERATE INSTABILITY, AND STRONG TO SEVERE STORMS APPEAR  
LIKELY FROM LATE AFTERNOON INTO THE OVERNIGHT HOURS. ALL SEVERE  
HAZARDS APPEAR POSSIBLE WITH FORECAST SOUNDINGS SHOWING FAVORABLE  
CONDITIONS FOR SUPERCELLS. AN INCREASING LOW LEVEL JET DURING THE  
EVENING AND OVERNIGHT HOURS SUGGESTS POTENTIAL FOR UPSCALE GROWTH  
DURING THE NIGHTTIME HOURS, WHICH WOULD INCREASE THE THREAT FOR  
DAMAGING WINDS ACROSS PARTS OF NORTHEAST MT INTO THE WESTERN  
DAKOTAS.  
   
..DAY 4/SAT - MID-ATLANTIC VICINITY
 
 
AN UPPER TROUGH OVER ONTARIO AND QUEBEC WILL DEEPEN ACROSS THE  
NORTHEAST AND MID-ATLANTIC VICINITY ON SATURDAY. A MOIST BOUNDARY  
LAYER WILL BE IN PLACE AS A COLD FRONT DEVELOPS EASTWARD ACROSS THE  
REGION DURING THE MORNING AND AFTERNOON. SOME STRONG TO SEVERE STORM  
POTENTIAL APPEARS POSSIBLE, HOWEVER GUIDANCE VARIES WITH REGARDS TO  
COVERAGE AND INTENSITY. UNCERTAINTY REMAINS TOO HIGH AT THIS TIME TO  
INCLUDE 15+ PERCENT SEVERE PROBABILITIES, BUT THEY MAY BECOME  
NECESSARY IN LATER OUTLOOKS.  
   
..DAY 5/SUN - EASTERN DAKOTAS INTO WESTERN MN
 
 
MOISTURE WILL STREAM NORTHWARD ACROSS EASTERN PORTIONS OF THE  
NORTHERN/CENTRAL PLAINS ON INCREASING SOUTHERLY LOW LEVEL FLOW AHEAD  
OF A SURFACE LOW OVER THE NORTHERN HIGH PLAINS. SOME CONVECTION  
COULD BE ONGOING DURING THE MORNING AS A CONTINUATION OF AN MCS FROM  
THE DAY 4/SAT PERIOD OVER PARTS OF ND OR MN. NEVERTHELESS, A VERY  
MOIST AND UNSTABLE ENVIRONMENT IS EXPECTED ACROSS THE EASTERN  
DAKOTAS INTO WESTERN MN. AS A SURFACE LOW OVER EASTERN WY/MT SHIFTS  
EASTWARD INTO THE WESTERN DAKOTAS, CONVECTION IS EXPECTED TO  
REDEVELOP FROM LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT. INITIAL  
SUPERCELLS ARE POSSIBLE BEFORE ANOTHER ROUND OF UPSCALE GROWTH INTO  
A BOWING MCS DEVELOPS OVERNIGHT INTO WESTERN MN. THE SOUTHWARD  
EXTENT OF SEVERE POTENTIAL IS UNCERTAIN, BUT AN ISOLATED THREAT  
COULD DEVELOP INTO PORTIONS OF NE ALONG A SURFACE TROUGH, AND SEVERE  
PROBABILITIES MAY NEED TO BE ADDED TO THIS AREA IN SUBSEQUENT  
OUTLOOKS.  
   
..DAYS 5-8/SUN-WED - LOWER MS VALLEY TO UPPER GREAT LAKES
 
 
THERE IS QUITE A BIT OF UNCERTAINTY SURROUNDING THE EVOLUTION OF  
WHAT IS CURRENTLY TROPICAL STORM CRISTOBAL. THE TS IS FORECAST BY  
THE NATIONAL HURRICANE CENTER TO BE NEAR THE LA COAST SUNDAY NIGHT.  
BEYOND THIS, THE REMAINS OF THE SYSTEM ARE EXPECTED TO EVENTUALLY  
MERGE WITH THE WESTERN UPPER TROUGH AS IT EJECTS EASTWARD INTO THE  
PLAINS EARLY NEXT WEEK, BREAKING DOWN THE UPPER RIDGE AND ALLOWING  
THE TROPICAL SYSTEM TO DEVELOP NORTHWARD FROM THE GULF COAST. SOME  
SEVERE THREAT WILL LIKELY ACCOMPANY THIS PROCESS FROM THE LOWER/MID  
MS VALLEY TO THE UPPER GREAT LAKES EARLY TO MIDDLE OF NEXT WEEK.  
HOWEVER, UNCERTAINTY IS TOO HIGH, PRECLUDING SEVERE PROBS AT THIS  
TIME.  
 
..LEITMAN.. 06/03/2020  
 
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