Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 260855
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
255 AM MDT THU MAR 26 2015

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 255 AM MDT THU MAR 26 2015

FRONTAL BOUNDARY WILL REMAIN IN PLACE ACROSS THE
REGION...WITH PERTURBED NW FLOW ALOFT...SUPPORTING UNSETTLED
WEATHER THROUGH TONIGHT. THE FIRST OF TWO MID LEVEL IMPULSES IS
IN THE PROCESS OF ADVECTING SE ACROSS THE NORTHERN PLAINS. THIS
FEATURE COUPLED WITH A POTENT UPPER LEVEL JET STREAK IS SUPPORTING
INCREASING COVERAGE OF PRECIP ACROSS THE NE HALF OF THE FA. THIS
WILL CONTINUE THROUGH MORNING. STEEP LL LAPSE RATES COUPLED WITH
PAC MOISTURE WILL SUPPORT INSTABILITY SHRA OVER MOST OF THE FA
THIS AFTERNOON WITH A SECONDARY IMPULSE SUPPORTING ANOTHER UPGLIDE
PUSH TONIGHT...WITH RESULTING CHANCES FOR MAINLY RAIN SHRA GIVEN
WARM BL CONDS PER ONGOING WAA. MUCH WARMER WEATHER WILL ARRIVE
FRIDAY AS THE LL FRONTAL ZONE SHIFTS EAST...WITH WARM NW PAC FLOW
SPREADING OVER THE FA.

TODAY...FGEN SNOWS WILL CONTINUE THROUGH MORNING ACROSS MAINLY THE
EASTERN HALF OF THE FA. BEST FORCING WILL BE ALONG A NARROW BAND
ACROSS NW SD WHERE A QUICK INCH OR TWO IS POSSIBLE. HOWEVER...GIVEN
INCREASING CONVECTIVE NATURE PER STEEP MID AND LL LAPSE
RATES...DISRUPTION OF BETTER BANDING WILL LIKELY OCCUR LIMITING
SNOW AMOUNTS TO A DEGREE. MAIN LOBE OF UPPER LEVEL FORCING WILL
SHIFT SE OUT OF THE REGION WITH DIURNAL HEATING AND STEEP LL LAPSE
RATES SUPPORTING MORE SHOWERY ACTIVITY THIS AFTERNOON. ESP ACROSS NE
WY/THE BH/AND FAR WESTERN SD. WAA WILL SUPPORT MORE RAIN SHOWER
CHANCES...ESP OUTSIDE THE BH. TEMPS WILL BE A LITTLE WARMER THAN
YESTERDAY WITH 40S AND LOWER 50S FOR HIGHS.

TONIGHT...SCT CONVECTIVE SHRA WILL LINGER INTO THE EVENING...WITH
RENEWED CHANCES FOR PRECIP LATER IN THE EVENING AS THE NEXT MID LEVEL
IMPULSE ARRIVES. WARM PROFILES PER ONGOING WAA WILL SUPPORT MAINLY
RAIN SHOWER CHANCES...SAVE THE HIGHER ELEVATIONS OF THE BH AND
PERHAPS NW SD WHERE COOLER BL CONDS WILL BE IN PLACE. ANY SNOWFALL
WILL BE MINIMAL GIVEN WARM CONDS. LOWS WILL MAINLY BE IN THE 30S.

FRIDAY...LL FRONTAL ZONE WILL FINALLY SHIFT EAST WITH ASSOCIATED
PRECIP CHANCES ENDING. DIURNAL INSTABILITY COUPLED WITH DEEP MIXING
AND MOIST NW FLOW COULD SUPPORT A FEW ISOLD HIGH BASED SHRA FRIDAY
AFTERNOON ON THE SD PLAINS. HOWEVER...GIVEN SUBSIDENT FLOW
ALOFT...LEFT ANY WX MENTION OUT ATTM. MUCH WARMER CONDS EXPECTED
WITH HIGHS IN THE 60S MOST AREAS.

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 255 AM MDT THU MAR 26 2015

A VERY WARM START TO THE WEEKEND AS A SHORTWAVE RIDGE
PASSES OVER THE NORTHERN PLAINS. HIGHS ON SATURDAY WILL BE IN THE
70S TO AROUND 80 DEGREES ACROSS THE PLAINS. THERE IS POTENTIAL FOR
FIRE WEATHER ISSUES ACROSS PARTS OF NORTHEAST WY INTO SOUTHWEST SD
IF WINDS INCREASE ENOUGH IN THE AFTERNOON. A COLD FRONT WILL PASS
THROUGH THE AREA LATE IN THE AFTERNOON AND EVENING...WITH A CHANCE
FOR SHOWERS AND GUSTY WINDS BEHIND IT.

MEDIUM RANGE MODELS IN DECENT AGREEMENT FOR THE REST OF THE EXTENDED
PERIOD. SLIGHTLY COOLER AIR CAN BE EXPECTED FOR SUNDAY INTO EARLY
NEXT WEEK...BUT STILL WELL ABOVE AVERAGE. ANOTHER UPPER LEVEL
DISTURBANCE AND COLD FRONT WILL LIKELY PUSH THROUGH THE REGION LATE
TUESDAY INTO WEDNESDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING
ISSUED AT 255 AM MDT THU MAR 26 2015

AREAS OF LIGHT SNOW AND MVFR/IFR CONDITIONS CAN BE
EXPECTED ACROSS MOSTLY FAR NORTHEAST WY AND WESTERN SD THIS MORNING
AS AN UPPER LEVEL DISTURBANCE QUICKLY SLIDES THROUGH THE AREA.
CONDITIONS WILL IMPROVE IN MOST AREAS BY THE EARLY AFTERNOON...
EXCEPT OVER THE NORTHERN BLACK HILLS AREA. ANOTHER WEAK DISTURBANCE
WILL THEN MOVE THROUGH THE AREA TONIGHT...WITH AREAS OF LIGHT SNOW
AND MVFR CONDITIONS.

&&

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

$$

SHORT TERM...JC
LONG TERM...26
AVIATION...26





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