Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 171738
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1038 AM MST MON NOV 17 2014

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 239 AM MST MON NOV 17 2014

09Z SURFACE ANALYSIS HAD MODEST PRESSURE GRADIENT OVER CWA WITH
HIGH OVER ID AND LOW OVER LAKE SUPERIOR. CYCLONIC FLOW ALOFT PER
WATER VAPOR. STREAM OF LOW CLOUDS NOTED FROM SK INTO THE NE
PANHANDLE. THIS MOISTURE RIDING UP THE BLACK HILLS FOR SOME WEAK
UPSLOPE ENHANCEMENT...IN LINE WITH FROUDE NUMBERS.

TODAY...CYCLONIC FLOW CONTINUES WITH STREAM OF LOW LEVEL MOISTURE
BECOMING LESS DEFINED THROUGH THE AFTERNOON HOURS WHICH WILL RESULT
IN A SLOW DECREASE IN -SHSN/UPSLOPE ENHANCEMENT. MINOR ADDITIONAL
ACCUMULATIONS POSSIBLE OVER/NEAR NORTHERN BLACK HILLS...SO WILL
DROP WINTER WEATHER ADVISORY WITH MORNING PACKAGE. BREEZY/WINDY
SPOTS CONTINUE WITH STEEP LOW LEVEL LAPSE RATES...BUT WARM AIR
ADVECTION SHOULD TEMPER SPEEDS BY AFTERNOON.

TONIGHT...LOW LEVEL WARM AIR ADVECTION CONTINUES AHEAD OF SHORTWAVE
DROPPING INTO SOUTHERN AB/SK. TEMPERATURES TRICKY WITH SNOW ON
GROUND AND WARMER AIR ALOFT.

TUESDAY...SHORTWAVE WILL RACE THROUGH THE CWA LATE IN THE DAY
DRAGGING A COLD FRONT THROUGH THE CWA. COULD BE SOME -SHSN WITH
FRONT...BUT MAIN CHANCES OVER THE HIGHER TERRAIN GIVEN UPSLOPE
COMPONENT TO WINDS BEHIND COLD FRONT. GUSTY NORTHWEST WINDS
EXPECTED WITH FRONT...BUT MUCH WARMER TEMPERATURES AHEAD OF FRONT
WILL PREVENT NOTABLE BLSN. LOW LEVEL MOISTURE IS SCOURED OUT LATER
TUESDAY NIGHT LEAVING DRY WEATHER AFTER 06Z WEDNESDAY.

&&

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 239 AM MST MON NOV 17 2014

WITH ANOTHER ARCTIC AIRMASS OVER THE NORTHERN PLAINS...TEMPS WILL
BE COOLER ON WED/THU...IN THE 20S AND 30S. WARMER AIR WILL ADVECT
IN FOR THE END OF THE WEEK AS A TRANSIENT UPPER RIDGE BUILDS IN
OVER THE CENTRAL CONUS. DRY WEATHER IS EXPECTED INTO THE
WEEKEND...BUT A MORE ACTIVE PATTERN IS POSSIBLE FOR EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1030 AM MST MON NOV 17 2014

ISOLATED SNOW SHOWERS WILL PERSIST ACROSS WESTERN SOUTH DAKOTA AND
THE NORTHERN BLACK HILLS AND NORTHEASTERN FOOTHILLS...PRODUCING
MVFR TO LOCAL IFR CONDITIONS. SNOW SHOWERS WILL GRADUALLY
DIMINISH BY LATE AFTERNOON. MVFR CIGS ARE EXPECTED THROUGH LATE
AFTERNOON OVER NORTHEASTERN WYOMING. NORTHWEST WINDS WILL BE
BREEZY THIS AFTERNOON...DIMINISHING THIS EVENING. VFR CONDITIONS
ARE EXPECTED THIS EVENING AND OVERNIGHT.

&&

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

$$

SHORT TERM...HELGESON
LONG TERM...POJORLIE
AVIATION...15






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