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Displaying AFOS PIL: AFDUNR Received: 2014-09-20 23:03 UTC
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671 FXUS63 KUNR 202303 AFDUNR AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 503 PM MDT SAT SEP 20 2014 .UPDATE... ISSUED AT 459 PM MDT SAT SEP 20 2014 NORTHWEST WINDS WILL CONTINUE TO DIMINISH AS HIGH PRESSURE BUILDS INTO THE AREA THIS EVENING. HAVE UPDATED THE FORECAST TO EXPIRE THE WIND ADVISORY THAT WAS PREVIOUSLY IN EFFECT. && .SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT ISSUED AT 225 PM MDT SAT SEP 20 2014 20Z SURFACE ANALYSIS SHOWED TIGHT GRADIENT OVER THE SD PLAINS WITH WINDS PEAKING SO WILL KEEP ADVISORY GOING UNTIL EXPIRATION AT 23Z. TONIGHT...HIGH PRESSURE BUILDS INTO THE CWA WITH CLEAR SKIES AND DECREASING WINDS. TEMPERATURES SHOULD FALL OFF NICELY WITH READINGS NEAR GUIDANCE BY MORNING. SUNDAY...TRANSIENT UPPER RIDGE MOVES FROM THE ROCKIES INTO THE NORTHERN PLAINS AS SURFACE ANTICYCLONE MOVES FROM THE CWA TO THE MIDWEST. RETURN FLOW WILL DEVELOP ON THE BACK SIDE OVER THE WEST WITH WEAK WARM AIR ADVECTION. TEMPERATURES WILL BE SEASONAL. SUNDAY NIGHT...UPPER LOW MOVES INTO ID/WY/UT...PINCHING OFF UPPER RIDGE. LATEST GUIDANCE SUGGESTS SLOWER RETURN OF MOISTURE SO HAVE BACKED OFF ON POPS UNTIL VERY LATE SUNDAY NIGHT OVER THE FAR SOUTHWEST. LOWS NEAR GUIDANCE EXPECTED. && .LONG TERM...MONDAY THROUGH SATURDAY ISSUED AT 225 PM MDT SAT SEP 20 2014 MODELS ARE STILL IN AGREEMENT ABOUT A CUT-OFF LOW CROSSING THE REGION THROUGH FIRST HALF OF NEXT WEEK. RETURN FLOW WILL SET UP WITH MOISTURE ADVECTING IN THE DEEP SOUTHERLY FLOW. THIS COMBINED WITH SOME MINIMAL INSTABILITY WILL ALLOW FOR SHOWERS AND THUNDERSTORMS MONDAY AND TUESDAY. DRIER AIR WILL RETURN WEDNESDAY AS A RIDGE BUILDS...HOWEVER NOW BOTH THE ECM AND GFS SHOW A SECONDARY UPPER LOW DEVELOPING AND RETROGRADING BACK OVER THE NRN PLAINS. MODELS SHOWED A SIMILAR SOLUTION TWO OR THREE DAYS AGO BEFORE QUICKLY ABANDONING IT...BUT NOW ITS BACK AGAIN. EITHER WAY...SEE NO REASON TO ADD POPS. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE AVERAGE FOR THE SECOND HALF OF THE WEEK. && .AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING. ISSUED AT 501 PM MDT SAT SEP 20 2014 VFR CONDITIONS WITH MOSTLY CLEAR SKIES WILL CONTINUE TONIGHT AND ON SUNDAY. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...10 SHORT TERM...10 LONG TERM...13 AVIATION...13