Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 282006
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
206 PM MDT SAT MAR 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 201 PM MDT SAT MAR 28 2015

20Z SURFACE ANALYSIS HAD LOW PRESSURE OVER EAST CENTRAL SK WITH
COLD FRONT INTO NORTHWEST WY. WATER VAPOUR HAD STRONG SHORTWAVE
TROUGH FROM SOUTHERN AB INTO ID...WHICH WAS STARTING TO CUT DOWN
THE UPPER RIDGE OVER THE NORTHERN PLAINS PER WATER VAPOUR MATINEE.
100-250J/KG SBCAPE HAS DEVELOPED AHEAD OF THE COLD FRONT EVEN WITH
TD/S 25-35F RANGE. 6MB/3HR PRESSURE FALLS AHEAD OF THE FRONT
SUPPORTING BREEZY/WINDY SPOTS OVER THE CWA WITH WELL-DEFINED
SOUTHERLY FLOW. CONCERN THIS FORECAST REMAINS SHORTWAVE
TROUGH/COLD FRONT.

TONIGHT/EARLY SUNDAY...SHORTWAVE TROUGH ROCKETS INTO MN BY 12Z
SUNDAY. COLD FRONT...LIKELY VISIBLE TO THE NAKED EYE WHEN IT COMES
THROUGH DUE TO POCKETS OF DUST...WILL SLICE INTO NE BY 07Z. PRESSURE
RISES BEHIND IT FORECAST AT 7-11MB/3HR. 850MB WINDS REACH 40-55KTS
WITH WELL-DEFINED COLD AIR ADVECTION. FORECAST SOUNDINGS SHOW
WELL-MIXED BOUNDARY LAYER NEAR/BEHIND COLD FRONT. HIGH WINDS LIKELY
OVER MUCH OF THE PLAINS WITH GUSTS TO 70 MPH POSSIBLE IN THE SQUEEZE
ZONE JUST EAST OF THE BLACK HILLS. HIGH WINDS WILL PERSIST A BIT
LONGER GIVEN SECONDARY PRESSURE BUBBLE OVERNIGHT...SO WILL EXTEND
HEADLINES ON THE SD PLAINS A FEW HOURS.

200-400J/KG SBCAPE WILL BE AVAILABLE ALONG THE COLD FRONT FOR HIGH
BASED -SHRA/-TSRA LATE THIS AFTERNOON/EARLY. THESE CONVECTIVE
ELEMENTS MAY PROMOTE ADDITIONAL DOWNWARD MOMENTUM OF STRONG
WINDS...PERHAPS A SEVERE THUNDERSTORM WARNING OR TWO MAY BE NEEDED
FOR THE STRONGEST CELLS. TEMPERATURES WILL BE NEAR GUIDANCE TONIGHT.

SUNDAY...WINDS WILL QUICKLY DIMINISH DURING THE DAY AS SYSTEM PUSHES
EAST LEAVING BEHIND SLIGHTLY COOLER TEMPERATURES DRY WEATHER.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 201 PM MDT SAT MAR 28 2015

UPPER LEVEL RIDGE CROSSES THE NORTHERN PLAINS FOR MONDAY AND
TUESDAY...WITH DRY CONDITIONS AND WELL ABOVE AVERAGE TEMPERATURES
EXPECTED. A STRONG SHORTWAVE TROF WILL SLIDE ACROSS THE NORTHERN
PLAINS ON WEDNESDAY...WITH SOME SHOWERS POSSIBLE...ALTHOUGH MODELS
CONTINUE TO TREND DRIER WITH THIS SYSTEM FOR OUR CWA. A STRONG
COLD FRONT WILL ACCOMPANY THIS UPPER DISTURBANCE...BRINGING
SLIGHTLY COOLER TEMPERATURES AND GUSTY NORTHWEST WINDS TO THE
AREA.

UPPER FLOW BECOMES MORE NORTHWESTERLY FOR THE END OF THE WEEK...WITH
A TROUGH MOVING THROUGH THE REGION. MODELS ARE STARTING TO COME INTO
BETTER AGREEMENT...KEEPING THE BEST ENERGY JUST SOUTH OF THE AREA.
ECM/GFS/GEM ARE ALL HINTING AT A BAND OF PRECIP SETTING UP OVER THE
SOUTHERN HALF OF THE CWA THURSDAY NIGHT INTO FRIDAY...WITH
CONDITIONS DRYING OUT LATE FRIDAY INTO NEXT WEEKEND. SOME OF THE
PRECIP MAY BE IN THE FORM OF SNOW AS LOWS THURSDAY NIGHT WILL BE
BELOW FREEZING IN MOST PLACES. TEMPERATURES FOR THE END OF THE WEEK
LOOK TO BE NEAR AVERAGE...IN THE 50S.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 201 PM MDT SAT MAR 28 2015

VFR CONDITIONS ARE EXPECTED THROUGH MID AFTERNOON. A VERY STRONG
COLD FRONT WILL MOVE THROUGH NORTHEAST WYOMING AND WESTERN SOUTH
DAKOTA LATE THIS AFTERNOON THROUGH LATE TONIGHT. NORTHWEST WINDS
OF 30 TO 45 MPH WITH GUSTS AROUND 60 MPH WILL BE POSSIBLE INTO
EARLY SUNDAY MORNING. IN ADDITION...ISOLATED THUNDERSTORMS WILL BE
POSSIBLE FROM LATE THIS AFTERNOON THROUGH LATE THIS EVENING AS THE
STRONG COLD FRONT CROSSES THE AREA. MVFR CEILINGS AND VISIBILITIES
WILL BE POSSIBLE WITH ANY STRONGER SHOWERS/STORMS. MVFR CEILINGS
WILL BE LIKELY ACROSS THE HIGHER TERRAIN OF THE BLACK HILLS AND
NORTHEAST WYOMING LATE TONIGHT THROUGH EARLY SUNDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 201 PM MDT SAT MAR 28 2015

WARM TEMPERATURES WITH DRY WESTERLY FLOW WILL RESULT IN CRITICAL
FIRE WEATHER CONDITIONS INTO EARLY THIS EVENING ACROSS NORTHEAST
WYOMING AND WESTERN SOUTH DAKOTA. MINIMUM RELATIVE HUMIDITY WILL
BE NEAR 15 PERCENT WITH WESTERLY WINDS OF 20 TO 30 MPH. A COLD
FRONT MOVES THROUGH THE AREA LATE THIS AFTERNOON AND EVENING.
WINDS WILL SHIFT TO THE NORTHWEST...WITH GUSTS GREATER THAN 50 MPH.

BREEZY WINDS WILL PERSIST INTO SUNDAY MORNING ACROSS THE SD
PLAINS...GRADUALLY DIMINISHING THROUGHOUT THE DAY. BY MID
AFTERNOON NORTHWEST WINDS MAY STILL BE 15 TO 20 MPH...BUT WITH
MINIMUM RH VALUES ONLY 20 PERCENT...WILL NOT ISSUE ANY HEADLINES
FOR SUNDAY AT THIS POINT.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR SDZ260>264.

     HIGH WIND WARNING FROM 6 PM THIS EVENING TO 9 AM MDT SUNDAY FOR
     SDZ013-014-026-030>032-042>044-072>074.

     WIND ADVISORY FROM 8 PM THIS EVENING TO 11 AM CDT SUNDAY FOR
     SDZ046-047-049.

     WIND ADVISORY FROM 6 PM THIS EVENING TO 5 AM MDT SUNDAY FOR
     SDZ027-041.

     HIGH WIND WARNING UNTIL 6 AM MDT SUNDAY FOR SDZ001-002-012-025.

WY...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ259-297>299.

     HIGH WIND WARNING UNTIL 6 AM MDT SUNDAY FOR WYZ071.

     HIGH WIND WARNING UNTIL MIDNIGHT MDT TONIGHT FOR WYZ054>056-058.

&&

$$

SHORT TERM...HELGESON
LONG TERM...POJORLIE
AVIATION...POJORLIE
FIRE WEATHER...POJORLIE



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