Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 281937
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
137 PM MDT THU APR 28 2016

.UPDATE...
ISSUED AT 1036 AM MDT THU APR 28 2016

SURFACE OBS/REGIONAL WEB CAMS SHOW AREAS OF FOG PERSISTING ACROSS
THE NRN BLKHLS INTO THE ERN FOOTHILLS. HAVE UPDATED THE FORECAST
TO KEEP FOG IN AT LEAST THROUGH THE REST OF THE MORNING ALONG WITH
LIGHT RAIN/SNOW. ALSO MADE MINOR ADJUSTMENTS TO POPS BASED ON
LATEST TRENDS ESPECIALLY THROUGH THE AFTN HOURS. DROPPED MAX TEMPS
SLIGHTLY ACROSS NW SD PLAINS GIVEN THE AMOUNT OF SNOW RECEIVED
OVERNIGHT. NO OTHER CHANGES NEEDED AT THIS TIME.

&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 246 AM MDT THU APR 28 2016

UPPER LEVEL ANALYSIS HAS WEAKENING CLOSED LOW ACROSS CENTRAL
IOWA...WITH CLOUD COVER AND LIGHT PRECIPITATION WRAPPING WESTWARD
INTO WESTERN SOUTH DAKOTA. WEAK RIDGING IS LOCATED ACROSS THE
SOUTHERN ROCKIES...WITH ANOTHER CLOSED LOW MOVING INTO NORTHERN
ARIZONA. AT THE SURFACE...LOW PRESSURE IS LOCATED IN WESTERN IOWA
WITH WEAK HIGH PRESSURE ACROSS EASTERN MONTANA INTO FAR WESTERN
SOUTH DAKOTA. WEAK PRESSURE GRADIENT BETWEEN THESE TWO FEATURES IS
PRODUCING LIGHT NORTHERLY WINDS ACROSS MUCH OF THE FORECAST AREA.
TEMPERATURES AT 3AM ARE IN THE 30S...WITH SOME UPPER 20S ACROSS
THE BLACK HILLS.

TODAY...THE UPPER TROUGH/LOW/SHEAR ZONE WILL CONTINUE TO WEAKEN
AS IT SHIFTS EAST. LIGHT PRECIPITATION WILL CONTINUE ACROSS MUCH
OF THE AREA...WITH PRECIPITATION SLOWLY DIMINISHING THROUGH THE
DAY. RAIN/SNOW/DRIZZLE MIX IS EXPECTED ACROSS MUCH OF THE
AREA...WITH LITTLE SNOW ACCUMULATION. SOME AREAS OF FOG WILL ALSO
BE POSSIBLE THROUGH MID MORNING. SKIES WILL REMAIN CLOUDY THROUGH
MUCH OF THE DAY...WITH HIGH TEMPERATURES REMAINING WELL BELOW
AVERAGE...IN THE MID 30S TO MID 40S.

TONIGHT...UPPER LOW AND RESIDUAL SHEAR ZONE WILL FURTHER
WEAKEN...WITH SOME ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS
LINGERING ACROSS THE AREA...MAINLY FROM THE BLACK HILLS NORTH.
OVERALL PRECIP ACTIVITY WILL BE ON THE DECREASE. THE UPPER LOW
OVER THE SOUTHWESTERN CONUS WILL MOVE THROUGH THE SOUTHERN AND
CENTRAL ROCKIES...AND WILL SPREAD MOISTURE AND LIFT NORTHWARD INTO
SOUTHERN WYOMING AND THE NEBRASKA PAN HANDLE LATE. LOW
TEMPERATURES WILL FALL INTO THE MID 20S TO MID 30S.

FOR FRIDAY...UPPER LOW CROSSING THE ROCKIES WILL MOVE INTO THE
CENTRAL PLAINS BY MID DAY FRIDAY. CLOUD COVER AND PRECIP SHIELD
WILL SLOWLY PROGRESS NORTHWARD ACROSS WESTERN SOUTH DAKOTA AND
NORTHEASTERN WYOMING THROUGH THE DAY ON FRIDAY...MOVING INTO
NORTHWEST SOUTH DAKOTA BY FRIDAY EVENING. TEMPERATURES ON FRIDAY
SHOULD MAINLY BE IN THE 40S...SO PRECIP FROM THIS SYSTEM SHOULD
FALL AS RAIN. THE EXCEPTION WILL BE ACROSS THE HIGHER ELEVATIONS
OF NORTHEAST WYOMING AND THE BLACK HILLS...WHERE TEMPERATURES WILL
REMAIN IN THE 30S...AND A MIX OF RAIN AND SNOW WILL BE POSSIBLE.
BY LATE FRIDAY NIGHT...TEMPERATURES WILL COOL INTO THE LOWER TO
MID 30S ACROSS WESTERN AREAS...WITH A RAIN/SNOW MIX MORE PROBABLE.

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 246 AM MDT THU APR 28 2016

MODELS IN DECENT AGREEMENT FOR THE WEEKEND...WITH UPPER LOW OVER
SOUTHERN NEBRASKA. PRECIPITATION WRAPPING AROUND UPPER LOW WILL
RESULT IN COOL/WET CONDITIONS WITH BEST CHANCE OF PRECIPITATION
ALONG AND SOUTH OF INTERSTATE 90. HAVE TRENDED LOWER WITH POPS
ACROSS NORTHWEST SOUTH DAKOTA. THERMAL PROFILES SUGGEST SOME SNOW
MAY MIX IN WITH THE RAIN SATURDAY MORNING AND LATE SATURDAY NIGHT.
UPPER LEVEL RIDGE BUILDS ACROSS THE NORTHERN ROCKIES/PLAINS NEXT
WEEK. WILL BE DRY WITH TEMPERATURES ABOVE AVERAGE FOR THE LAST
HALF OF THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 135 PM MDT THU APR 28 2016

RATHER WDSPRD MVFR CIGS...WITH HIGHER TERRAIN IFR/LIFR
CONDITIONS...EXPECTED TO CONTINUE INTO THE EARLY EVENING HOURS.
AREAS OF EXTENT OF IFR CIGS WILL INCREASE TONIGHT...WITH SOME
AREAS OF LIFR CIGS/FOG EXPECTED AROUND THE BLKHLS.

&&

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

$$

SHORT TERM...15
LONG TERM...7
AVIATION...JOHNSON



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