Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 281708
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1108 AM MDT SAT MAR 28 2015

.UPDATE...
ISSUED AT 1004 AM MDT SAT MAR 28 2015

15Z SURFACE ANALYSIS HAD LOW PRESSURE OVER SOUTHERN SK WITH COLD
FRONT INTO ID. P6SM SKC WITH UPPER/THERMAL RIDGE PEAKING OVER THE
CWA TODAY. 12Z KUNR SOUNDING SUPPORTS 76F FOR A HIGH WITHOUT THE
ONGOING LOW LEVEL WARM AIR ADVECTION. LATEST GUIDANCE VERY SIMILAR
TO ONGOING FORECAST. STRONG COLD FRONT WITH 8-11MB/3HR PRESSURE
RISES PUSHES INTO THE CWA AROUND 23Z AND EXITS CWA AROUND 06Z.
NAM/RAP SHOW 45-55KT 850MB WINDS AND STRONG COLD AIR ADVECTION.
WIND HIGH LIGHTS LOOK GOOD. SUFFICIENT SBCAPE AHEAD IT FOR HIGH-
BASED -TSRA ALONG FRONTAL BOUNDARY AND THEN POST FRONT SHOWERS
CHANCES AS SHORTWAVE TROUGH MOVES ACROSS MT INTO ND.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 245 AM MDT SAT MAR 28 2015

CURRENT SURFACE MAP PLACES LOW OVER ALBERTA..WITH WARM FRONT
THROUGH NORTHEAST MONTANA INTO CENTRAL SOUTH DAKOTA. SHARP UPPER
LEVEL RIDGE ACROSS THE ROCKIES...WITH STRONG PACIFIC NORTHWEST
SHORTWAVE ABOUT TO CRASH THROUGH THE RIDGE.

WILL BE VERY WARM ACROSS THE AREA TODAY...WITH RECORD HIGHS
POSSIBLE. 925-850MB TEMPERATURES. SUPPORT HIGHS AROUND 80 ON THE
PLAINS EAST OF THE BLACK HILLS. DEEP MIXING WILL ALLOW FOR GUSTY
SOUTHWEST WINDS ACROSS NORTHEAST WYOMING/WESTERN SOUTH DAKOTA THIS
AFTERNOON. SHORTWAVE TRACKS INTO EASTERN MONTANA THIS
AFTERNOON...AND THROUGH THE WESTERN DAKOTAS THIS EVENING. STRONG
COLD FRONT WILL BLAST THROUGH THE FORECAST AREA LATE THIS
AFTERNOON/EVENING WITH SIGNIFICANT PRESSURE FALL- RISE COUPLET.
ISALLOBARIC FORCING WITH 8-12MB/3H PRESSURE RISES...900-800MB
WINDS OF 50-60KTS...AND STEEP LOW LEVEL LAPSE RATES ALL POINT TO
HIGH WINDS BEHIND THE COLD FRONT. A FEW HIGH BASED SHOWERS/TSRA
WILL ALSO ENHANCE DOWNWARD MOMENTUM OF STRONGER WINDS ALOFT. WILL
UPGRADE HIGH WIND WATCH TO A WARNING.

WINDS DECREASE FOR SUNDAY...BUT WILL STILL BE BREEZY ON THE SOUTH
DAKOTA PLAINS. TEMPERATURES NEAR GUIDANCE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 245 AM 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. A STRONG
COLD FRONT WILL ACCOMPANY THIS UPPER DISTURBANCE...BRINGING SLIGHTLY
COOLER TEMPERATURES AND GUSTY NORTHWEST WINDS TO THE AREA. UPPER
FLOW BECOMES MORE NORTHWEST THROUGH THE END OF THE WEEK...WITH
MODELS DIVERGING IN THEIR SOLUTIONS. GFS BRINGS SOME WEAK ENERGY
THROUGH THE AREA ON THURSDAY...THEN DRIES IT OUT. EC AND GEM HAVE A
STRONGER UPPER SHORTWAVE LIFTING THROUGH THE AREA THURSDAY NIGHT
INTO FRIDAY WITH BETTER CHANCES FOR PRECIP. WILL GO WITH A FAIRLY
DRY SOLUTION FOR NOW UNTIL THERE IS BETTER AGREEMENT IN THE DAY 6
AND 7 PERIOD.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 1102 AM 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 TO 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 245 AM MDT SAT MAR 28 2015

WARM TEMPERATURES WITH DRY WESTERLY FLOW WILL RESULT IN CRITICAL
FIRE WEATHER CONDITIONS THIS AFTERNOON 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 OF 50 TO 60 MPH.

&&

.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 5 AM MDT SUNDAY FOR
     SDZ013-014-026-030>032-042>044-072>074.

     WIND ADVISORY FROM 8 PM THIS EVENING TO 6 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 FROM 5 PM THIS AFTERNOON TO 5 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 FROM 5 PM THIS AFTERNOON TO 5 AM MDT SUNDAY
     FOR WYZ071.

     HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT MDT
     TONIGHT FOR WYZ054>056-058.

&&

$$

UPDATE...HELGESON
SHORT TERM...7
LONG TERM...15
AVIATION...POJORLIE
FIRE WEATHER...7






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