Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 271131
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
431 AM MST TUE JAN 27 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
ISSUED AT 224 AM MST TUE JAN 27 2015

WATER VAPOR SHOWS LARGE AMPLITUDE RIDGE OVER THE ROCKIES/PLAINS.
AT THE SFC...HIGH PRESSURE HAS SHIFTED INTO THE UPPER MIDWEST WITH
DEEPENING LEE TROF ALONG THE ROCKY MOUNTAIN FRONT.

TODAY...LEE TROF WILL ADVANCE EWD INTO THE WRN DAKOTAS BY AFTN.
THICKNESS RIDGE PASSING OVERHEAD ALONG WITH DOWNSLOPE FLOW WILL
RESULT IN ANOTHER WARM DAY WITH PLENTY OF RECORD HIGHS EXPECTED.
THERMAL PROFILES SUGGEST TEMPS SHOULD BE AT LEAST AS WARM AS
MONDAY IF NOT A FEW DEGREES WARMER...BUT THAT WILL BE DEPENDENT ON
THE AMOUNT OF CIRRUS OVERHEAD.

WEDNESDAY...THE UPPER RIDGE WILL FLATTEN OVER THE NRN PLAINS AS A
STRONG DISTURBANCE MOVES THROUGH. MAJORITY OF GUIDANCE SUGGESTING
ENOUGH ENERGY FOR A FEW -SHRA ACROSS NERN WY...THE BLKHLS...AND
SWRN SD...ALTHOUGH MOISTURE WILL BE RATHER LIMITED. GUSTY NW WINDS
EXPECTED GIVEN COLD ADVECTION AND STEEP LO LVL LAPSE RATES...WITH
SOME AREAS ON THE SD PLAINS POSSIBLY REACHING NEAR ADVISORY
CRITERIA. WINDS WILL DECREASE WED EVENING WITH SFC HIGH BUILDING
IN OVERNIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY
ISSUED AT 224 AM MST TUE JAN 27 2015

TEMPERATURES WILL GRADUALLY LOWER TO NEAR OR BELOW AVERAGE LEVELS
BY THE WEEKEND AS NORTHWEST FLOW BRINGS COLDER AIR INTO THE
REGION. MEDIUM RANGE MODELS ARE IN BETTER AGREEMENT ON THIS...BUT
STILL SOME ISSUES WITH REGARD TO HOW COLD IT COULD BE AND HOW LONG
THE COLDER AIR REMAINS OVER THE REGION...WITH ECMWF STILL A BIT
MORE AGGRESSIVE THAN THE GFS AND GEM. WILL KEEP TRENDING COLDER
FOR THE WEEKEND...ESPECIALLY SUNDAY. CHANCES FOR SNOWFALL SHOULD
HOLD OFF UNTIL SATURDAY INTO SATURDAY NIGHT AS A STRONGER
SHORTWAVE MOVES ACROSS THE REGION AND BRINGS IN THE COLDEST AIR.
ANY ACCUMULATIONS SHOULD BE LIGHT ACROSS THE AREA...WITH THE BEST
CHANCES OVER THE NORTHERN BLACK HILLS. SOME MILDER AIR COULD SLIDE
BACK EASTWARD INTO THE REGION EARLY NEXT WEEK...BUT THAT IS VERY
UNCERTAIN AT THIS POINT.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING
ISSUED AT 430 AM MST TUE JAN 27 2015

VFR CONDITIONS CAN BE EXPECTED THROUGH THE FORECAST PERIOD.

&&

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

$$

SHORT TERM...JOHNSON
LONG TERM...26
AVIATION...26






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