837  
FXUS63 KUNR 191115  
AFDUNR  
 
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY  
NATIONAL WEATHER SERVICE RAPID CITY SD  
515 AM MDT THU APR 19 2018  
   
DISCUSSION
 
(TODAY THROUGH WEDNESDAY)  
ISSUED AT 320 AM MDT THU APR 19 2018  
 
CURRENT SURFACE ANALYSIS SHOWS HIGH PRESSURE CENTERED OVER THE  
CENTRAL DAKOTAS INTO EASTERN NE. UPPER LEVEL ANALYSIS SHOWS LOW  
PRESSURE OVER THE SOUTHERN GREAT LAKES REGION, WITH ANOTHER LOW  
DIGGING SOUTHEAST INTO CA. A RIDGE IS IN PLACE BETWEEN THE TWO  
SYSTEMS ACROSS THE ROCKIES AND HIGH PLAINS. SKIES ARE MOSTLY CLEAR  
ACROSS THE AREA, WITH SCATTERED HIGH CLOUDS PASSING OVERHEAD, BUT  
COULD SEE SOME PATCHY FOG DEVELOP ACROSS PARTS OF THE SD PLAINS  
EARLY THIS MORNING. TEMPS ARE MOSTLY IN THE 30S WITH LIGHT WINDS.  
 
RIDGE WILL BRING RELATIVELY NICE WEATHER AND SEASONABLE TEMPS TO  
MOST AREAS TODAY. HOWEVER, SOUTH CENTRAL SD WILL STILL SEE TEMPS  
BELOW AVERAGE WITH LINGERING SNOWPACK. SOUTHEASTERLY WINDS WILL  
INCREASE BEHIND EXITING HIGH PRESSURE, BECOMING BREEZY ACROSS  
NORTHEAST WY AND FAR WESTERN SD BY THE AFTERNOON.  
 
AS RIDGE PASSES EAST OF THE AREA TONIGHT, THE STORM SYSTEM OVER THE  
SOUTHWEST US WILL MOVE EAST ACROSS THE CENTRAL/SOUTHERN ROCKIES ON  
FRIDAY AND INTO THE CENTRAL/SOUTHERN PLAINS DURING THE EARLY PART OF  
THE WEEKEND. MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK,  
KEEPING THE BULK OF THE PCPN SOUTH OF THE FORECAST AREA. HOWEVER,  
JET ENERGY AHEAD OF THE SYSTEM WILL PUSH NORTHWARD INTO THE REGION  
BY FRIDAY MORNING AND BRING SOME SHOWERS, ESPECIALLY ACROSS THE  
SOUTHERN HALF OF THE CWA. THE BEST CHANCES LOOK TO BE LATE FRIDAY  
MORNING INTO FRIDAY NIGHT. THE HIGHER ELEVATIONS OF THE BLACK HILLS  
COULD SEE A MIX OR CHANGEOVER TO SNOW AT TIMES, ESPECIALLY INTO  
FRIDAY EVENING, BUT NOT EXPECTING MUCH IF ANY ACCUMULATION. THE  
STORM SYSTEM IS EXPECTED TO TURN SOUTHEAST INTO THE SOUTHERN PLAINS  
SATURDAY, WITH LINGERING PCPN SHIFTING SOUTH AND EAST OF THE CWA IN  
THE MORNING. THE REST OF THE WEEKEND LOOKS TO BE DRY AND MILD WITH  
HIGHS IN THE UPPER 50S AND 60S EACH DAY.  
 
ANOTHER SYSTEM IS THEN PROJECTED TO MOVE EAST ACROSS THE NORTHERN  
ROCKIES AND INTO THE NORTHERN PLAINS EARLY NEXT WEEK. SOME  
INCONSISTENCIES ON THE STRENGTH, TIMING, AND TRACK OF THE SYSTEM  
BETWEEN THE MEDIUM RANGE MODELS, BUT SHOULD SEE A GOOD CHANCE FOR  
MOSTLY RAIN SHOWERS SOMETIME MONDAY THROUGH EARLY TUESDAY. SOME SNOW  
IS POSSIBLE MONDAY NIGHT ACROSS NORTHEAST WY AND FAR WESTERN SD ON  
THE BACK SIDE OF THE SYSTEM. A FEW THUNDERSTORMS ARE ALSO POSSIBLE  
MONDAY AFTERNOON/EVENING. NEAR OR SLIGHTLY BELOW AVERAGE  
TEMPERATURES ARE GENERALLY EXPECTED MONDAY THROUGH WEDNESDAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)  
ISSUED AT 513 AM MDT THU APR 19 2018  
 
VFR CONDITIONS SHOULD CONTINUE THROUGH THE TAF PERIOD. GUSTY  
SOUTHEASTERLY WINDS WILL DEVELOP LATE MORNING AND CONTINUE INTO  
THE AFTERNOON ACROSS NORTHEASTERN WY, WHERE OCCASIONAL GUSTS OF  
30-35 KT ARE POSSIBLE.  
 

 
   
UNR WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
WY...NONE.  

 
 

 
 
DISCUSSION...26  
AVIATION...JC  
 
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