Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 261725
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 AM MDT SUN APR 26 2015

.UPDATE...
ISSUED AT 959 AM MDT SUN APR 26 2015

CURRENT SURFACE ANALYSIS SHOWS MAIN AREA OF LOW PRESSURE NOW OVER
SOUTHERN SK...WITH COLD FRONT EXTENDING SOUTH ACROSS WESTERN ND
INTO NORTHWEST SD AND NORTHEAST WY. UPPER LEVEL ANALYSIS SHOWS
NARROW RIDGING HOLDING ON OVER THE EASTERN PLAINS...WITH TROF OVER
THE CENTRAL AND SOUTHERN ROCKIES AND LOW PRESSURE OVER NORTHWEST
NM. SKIES REMAIN CLOUDY ACROSS NORTHEAST WY AND MUCH OF WESTERN
SD...WITH AREAS OF FOG LINGERING...MAINLY ACROSS THE BLACK HILLS
AREA. THERE ARE BREAKS IN THE CLOUDS OVER FAR EASTERN PORTIONS OF
THE CWA...ESPECIALLY SOUTH CENTRAL SD. KUDX RADAR SHOWS MOSTLY
LIGHT SHOWERS OVER FAR WESTERN SD AND NORTHEAST WY. REGIONAL
RADARS SHOW A HEAVIER BAND OF RAINFALL OVER FAR SOUTHEAST WY AND
FAR WESTERN NEB...MOVING NORTH-NORTHWEST. THIS AREA OF SHOWERS
SHOULD BRING MORE SIGNIFICANT RAINFALL TO MUCH OF NORTHEAST WY
THIS AFTERNOON. TEMPS RANGE FROM AROUND 40 OVER PORTIONS OF
NORTHEAST WY AND THE BLACK HILLS TO THE 50S OVER SOUTH CENTRAL SD.

HAVE UPDATED THE FORECAST TO MAKE SOME CHANGES TO POPS...QPF...
TEMPS...AND WIND FOR THE REST OF TODAY. RAISED POPS TO NEAR 100
PERCENT ACROSS MUCH OF NORTHEAST WY FOR THIS AFTERNOON AS THE BAND
OF SHOWERS MOVES THROUGH THE AREA FROM THE SOUTH. FURTHER EAST
INTO FAR WESTERN SD...LOOKING FOR HIGH POPS BUT LOWER AMOUNTS OF
RAINFALL FOR TODAY AS LIGHTER SHOWERS MOVE THROUGH. POPS TAPER
OFF SHARPLY TOWARD CENTRAL SD...WITH SOUTH CENTRAL SD REMAINING
DRY WITH SOME BREAKS OF SUNSHINE THROUGH THE AFTERNOON. LOWERED
HIGH TEMPS A FEW DEGREES FOR WESTERN AND CENTRAL PORTIONS OF THE
CWA AS CLOUD COVER AND PCPN KEEP TEMPS DOWN...SIMILAR TO
YESTERDAY. COLD FRONT OVER THE NORTHWEST CWA SHOULD STAY NEARLY
STATIONARY THROUGH THE AFTERNOON OR POSSIBLY MOVE BACK A BIT TO
THE NORTH AND WEST...SO LOW CONFIDENCE ON WIND DIRECTION ACROSS
NORTHEAST WY...NORTHWEST SD...AND EVEN THE RAPID CITY AREA WHERE
WINDS HAVE SWITCHED TO THE NORTH. MOST OF THE LINGERING SHOWER
ACTIVITY TONIGHT SHOULD BE LIMITED IN COVERAGE TO NORTHEAST WY
AND NORTHWEST SD BY MID TO LATE EVENING.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 303 AM MDT SUN APR 26 2015

UPPER LEVEL ANALYSIS HAS DEEP TROF ACROSS THE GREAT BASIN AREA
WITH DEVELOPING CLOSED LOW OVER THE FOUR CORNERS REGION. SKIES ARE
CLOUDY ACROSS THE NORTHERN PLAINS WITH SHORTWAVE ENERGY PRODUCING
WEAK SHOWER ACTIVITY ACROSS WESTERN SOUTH DAKOTA. AT THE
SURFACE...ONE AREA OF LOW PRESSURE IS LOCATED ACROSS SOUTHERN
SASKATCHEWAN...AND THE OTHER IS IN COLORADO...WITH A WEAK SURFACE
TROF IN BETWEEN THE TWO ACROSS WESTERN SOUTH DAKOTA. SURFACE HIGH
PRESSURE ACROSS NORTH CENTRAL MONTANA IS NOSING INTO NORTHEAST
WYOMING. TEMPERATURES AT 3AM ARE IN THE UPPER 30S AND 40S WITH
RELATIVELY LIGHT WINDS.

TODAY...DEVELOPING UPPER LOW WITHIN THE GREAT BASIN TROF WILL
CONTINUE TO EJECT SHORTWAVE ENERGY NORTHWARD INTO THE CENTRAL AND
NORTHERN HIGH PLAINS AS WEAK RIDGING HOLDS OVER THE UPPER MIDWEST.
MAJORITY OF MODELS IN DECENT AGREEMENT SHOWING A SIGNIFICANT WAVE
LIFTING THROUGH NORTHEAST WYOMING AND FAR WESTERN SD LATE THIS
MORNING INTO THE AFTERNOON. THIS SHOULD BRING SUBSTANTIAL RAIN
SHOWER ACTIVITY TO THIS AREA...AND HAVE RAISED POPS TO 80+. ONE
QUARTER TO ONE HALF AN INCH OF PRECIPITATION SEEMS REASONABLE FOR
MUCH OF NORTHEAST WYOMING AND THE FAR WESTERN BLACK HILLS. WITH
THE ABUNDANT MOISTURE ACROSS THE AREA...COMBINED WITH WEAK UPSLOPE
FLOW...SHOULD PRODUCE AREAS OF FOG THIS MORNING ACROSS NORTHEAST
WYOMING AND FAR WESTERN SOUTH DAKOTA. THE POTENTIAL FOR THUNDER
IS RATHER LOW...BUT WOULD NOT BE SURPRISED TO SEE A FEW STRIKES
OVER THE FAR SOUTHERN PORTIONS OF NE WY DURING THE LATE MORNING
AND AFTERNOON HOURS. HIGHS WILL RANGE FROM THE MID 40S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 60 OVER CENTRAL
SD...WHERE MAINLY DRY CONDITIONS AND A LITTLE SUNSHINE IS
POSSIBLE. RAIN SHOWERS WILL SLOWLY DECREASE IN COVERAGE SUNDAY
EVENING AS THE SHORTWAVE LIFTS NORTH...ESPECIALLY AFTER MIDNIGHT.
LOWS WILL MOSTLY BE IN THE MID 30S TO LOWER 40S...WITH THE HIGHER
BLACK HILLS INTO THE LOWER 30S BY MORNING. THERE STILL REMAINS A
SMALL CHANCE OF LIGHT ACCUMULATING SNOW LATE TONIGHT ACROSS THE
HIGHER ELEVATIONS OF SOUTHERN CAMPBELL COUNTY AND THE BLACK HILLS.

MONDAY...UPPER LOW REMAINS WELL SOUTH OF THE AREA...BUT NORTHERN
STREAM TROF CROSSES THE AREA. THIS WILL BRING ADDITIONAL CHANCES
FOR SHOWERS ON MONDAY INTO MONDAY EVENING. OTHERWISE...CLOUD COVER
WILL GENERALLY BE ON THE DECREASE LATE IN THE DAY...WITH
TEMPERATURES RISING INTO THE MID 50S TO UPPER 60S. A FEW SHOWERS
MAY LINGER INTO THE EVENING...BUT AREA SHOULD DRY OUT OVERNIGHT
WITH TEMPERATURES FALLING INTO THE 30S TO MID 40S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 303 AM MDT SUN APR 26 2015

AN UPPER LEVEL RIDGE WILL BUILD INTO THE NORTHERN PLAINS TUESDAY
INTO THURSDAY MORNING BRINGING DRY WEATHER AND A WARMING TREND. AS
THE UPPER RIDGE SHIFTS EAST FRIDAY INTO NEXT WEEK...WESTERLY FLOW
DEVELOPS WHICH WILL MAINTAIN PLEASANT TEMPERATURES. A DECENT
SHORTWAVE AND CHANCE FOR SHRA/TSRA WILL OCCUR LATER
THURSDAY/THURSDAY NIGHT AND THEN AGAIN LATE IN THE WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1118 AM MDT SUN APR 26 2015

WDSPRD IFR/LIFR CONDITIONS EXPECTED TO CONTINUE MUCH OF THE AFTN
ACROSS NERN WY AND FAR WRN SD...WITH CONDITIONS SLOWLY IMPROVING
THIS AFTN/EVE ACROSS PARTS OF WRN SD TO MVFR. CONDITIONS EXPECTED
TO CONTINUE IMPROVING ACROSS CNTRL SD TO VFR. WDSPRD -RA WILL
CONTINUE ACROSS NERN WY AND FAR WRN SD THROUGH TONIGHT...WITH
SOME SNOW POSSIBLE LATER TONIGHT ACROSS NERN WY AND THE BLKHLS.


&&

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

$$

UPDATE...26
SHORT TERM...15
LONG TERM...HELGESON
AVIATION...JOHNSON



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