Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 271728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 AM MST FRI FEB 27 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 306 AM MST FRI FEB 27 2015

UPPER LEVEL ANALYSIS HAS BROAD TROF ACROSS THE NORTHERN CONUS WITH
LIGHT NORTH TO NORTHWEST FLOW ACROSS THE NORTHERN PLAINS. SKIES
ARE MAINLY CLEAR ACROSS THE AREA WITH SOME LOW TO MID LEVEL CLOUDS
ACROSS PARTS OF NORTHEAST WYOMING AND FAR SOUTHWEST SOUTH DAKOTA.
AT THE SURFACE...ARCTIC HIGH IS LOCATED ACROSS THE CENTRAL AND
NORTHERN PLAINS...WITH LIGHT WINDS AND VERY COLD TEMPERATURES.
TEMPS AT 3AM RANGE FROM 10 BELOW ZERO TO A FEW DEGREES ABOVE ZERO
ACROSS THE AREA.

TODAY...BROAD UPPER TROF REMAINS OVER THE AREA WITH LIGHT
NORTHERLY UPPER FLOW CONTINUING. ARCTIC SURFACE HIGH SHIFTS A
LITTLE FURTHER SOUTH AND EAST...WITH RETURN FLOW STRENGTHENING
ACROSS THE AREA TODAY. BREEZY SOUTHERLY WINDS WILL PERSIST ACROSS
NORTHEAST WYOMING THROUGH EARLY AFTERNOON...BEFORE SUBSIDING A
BIT. LIGHT WINDS ACROSS THE SOUTH DAKOTA PLAINS WILL BECOME
SOUTHERLY THIS MORNING AND THEN INCREASE TO 15 TO 25 MPH BY
AFTERNOON. IN ADDITION...THE SOUTHERLY BOUNDARY LAYER FLOW WILL
BRING SLIGHTLY WARMER AIR INTO THE REGION. HIGH TEMPERATURES WILL
SLOWLY CLIMB INTO THE TEENS TO LOWER 20S TODAY...TAKING MOST OF
THE DAY TO REACH THEIR MAX LEVELS. SKIES SHOULD BE MOSTLY SUNNY.

TONIGHT...ARCTIC SURFACE HIGH SHIFTS FURTHER SOUTHEAST AS A WEAK
TROF OF LOW PRESSURE DEVELOPS ACROSS MONTANA. STRONG SOUTHERLY
RETURN FLOW DURING THE EVENING HOURS ACROSS THE SOUTH DAKOTA
PLAINS WILL DIMINISH QUICKLY IN THE EVENING AS A WEAK SURFACE TROF
SHIFTS INTO WESTERN SOUTH DAKOTA AFTER MIDNIGHT. SLIGHTLY MILDER
AIR WILL CONTINUE TO MOVE INTO THE AREA...WITH LOW TEMPERATURES
ONLY FALLING INTO THE SINGLE DIGITS AND TEENS ABOVE ZERO. SKIES
SHOULD REMAIN MOSTLY CLEAR.

SATURDAY...UPPER TROF REMAINS ACROSS THE NORTHERN PLAINS AS LOW
CLOSES OFF IN THE SW CONUS. WEAK SURFACE TROF CONTINUES TO SLOWLY
SHIFT EAST...WITH WINDS SHIFTING TO THE NORTHWEST AS TROF PASSES.
TEMPERATURES WILL BE SIMILAR TO FRIDAY...WITH POSSIBLY SOME LOW
30S ACROSS THE SOUTHERN SOUTH DAKOTA PLAINS IN THE VICINITY OF THE
SURFACE TROF. COOL TEMPERATURES REMAIN ACROSS THE AREA...WITH
LOWS FALLING INTO THE SINGLE DIGITS AND TEENS.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 306 AM MST FRI FEB 27 2015

COLDER THAN AVERAGE TEMPERATURES WILL CONTINUE ON SUNDAY AS A DRY
UPPER TROUGH AND A SURFACE HIGH REMAIN OVER THE REGION. THE
SURFACE HIGH WILL MOVE EAST ON MONDAY AS THE UPPER FLOW BECOMES
MORE WESTERLY AND WARMER PACIFIC SOURCED AIR SPREADS OVER THE
NORTHERN PLAINS. THIS WILL LEAD TO A BRIEF WARMUP...WITH NEAR
AVERAGE TEMPERATURES ON MONDAY. A LARGE LOW PRESSURE SYSTEM WILL
CROSS THE CNTRL PLAINS ON TUESDAY WHICH WILL CAUSE ARCTIC AIR TO
BE DRAWN SOUTHWARD INTO THE NORTHERN PLAINS. TUESDAY HIGH TEMPS
WILL ONLY REACH THE MID TEENS TO MID 20S. THE UPPER TROUGH WILL
ALSO BRING A CHANCE OF SNOW TO MUCH OF THE AREA TUESDAY/TUESDAY
NIGHT. DRY WEATHER IS EXPECTED WEDNESDAY WITH CONTINUED VERY COLD
TEMPERATURES AS THE ARCTIC HIGH CROSSES THE FORECAST AREA. WARMER
AND CONTINUED DRY WEATHER IS EXPECTED FOR THE REST OF THE WEEK AS
A STRONG UPPER RIDGE BUILDS TO THE WEST OF THE FORECAST AREA.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1028 AM MST FRI FEB 27 2015

VFR CONDITIONS WILL OCCUR OVER MOST OF THE AREA TODAY THROUGH
TONIGHT. THE EXCEPTION IS FOR LCL IFR AND SCT MVFR CIGS OVER NERN
WY AND FAR SWRN SD THROUGH EARLY AFTN...WHERE STRONG SLY FLOW WAS
ADVECTING LOW-LEVEL MOISTURE NWD. OTHERWISE...AREAS OF MVFR CIGS
WILL DEVELOP EARLY THIS EVENING OVER NERN WY WITH COVERAGE OF MVFR
CIGS INCREASING AFTER 06Z. THE NAM MOS APPEARED TOO AGGRESSIVE WITH
LOW CLOUDS RELATIVE TO THE GFS MOS...SO HAVE TRENDED THE KGCC CIGS
HIGHER THAN THAT GIVEN BY THE PESSIMISTIC NAM MOS.

&&

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

$$

SHORT TERM...15
LONG TERM...10
AVIATION...BUNKERS







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