000
FXUS63 KUNR 301659
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
959 AM MST FRI JAN 30 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 236 AM MST FRI JAN 30 2015

WATER VAPOR SHOWS SHORT WAVE CROSSING THE NRN ROCKIES AND FLATTENING
THE UPPER RIDGE IN PLACE. AT THE SFC...ASSOCIATED TROF IS ADVANCING
INTO ERN MT/ERN WY.

TODAY...SHORT WAVE WILL CROSS THE NRN PLAINS AND PUSH THE SFC
BOUNDARY THROUGH THE DAKOTAS. THIS WILL ALLOW THERMAL RIDGE TO
NOSE INTO THE CWFA AND HELP PUSH TEMPS INTO THE 50S ON THE SD
PLAINS...A LITTLE COOLER FURTHER WEST. VERY LITTLE MOISTURE WITH
THIS SYSTEM SO DRY CONDITIONS EXPECTED.

SATURDAY...A STRONGER DISTURBANCE EMBEDDED IN THE NW FLOW ALOFT
WILL SHIFT THROUGH THE NRN ROCKIES INTO THE NRN PLAINS. TEMP FCST
WILL BE TRICKY AS ARCTIC AIR ATTEMPTS TO BACK INTO THE SD PLAINS
WHILE INVERTED SFC TROF OVER NERN WY KEEPS TEMPS WARMER IN THE
WEST. AS 140KT JET STREAK ON BACK SIDE OF TROF ENTERS THE WRN
ZONES LATE ON SATURDAY/SATURDAY NIGHT...ARCTIC WILL PLUNGE SWD
THROUGH THE ENTIRE CWFA. LARGE SCALE ASCENT ASSOCIATED WITH JET
STREAK AND LO LVL CAA WITH RESULT IN WDSPRD LIGHT SNOW ACROSS WRN
SD...WITH LESS OF A CHANCE IN NERN WY. ACCUMS SHOULD BE LIGHT IN
MOST AREAS...GENERALLY 2 INCHES OR LESS...GIVEN LACK OF MOISTURE.
TEMPS SATURDAY NIGHT SHOULD SETTLE IN THE SINGLE DIGITS ON THE SD
PLAINS AND SLIGHTLY WARMER IN THE WRN ZONES.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 236 AM MST FRI JAN 30 2015

AN UNSETTLED AND COLDER PATTERN WILL PERSIST THROUGH AT LEAST
THE FIRST HALF OF NEXT WEEK. SHORTWAVE ENERGY WILL CROSS THE
NORTHERN PLAINS IN NORTHWEST FLOW...BRINGING LIGHT SNOW TO PARTS
OF THE AREA FROM TIME TO TIME. BEST CHANCES FOR LIGHT SNOW WILL BE
MONDAY NIGHT INTO TUESDAY MORNING ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE
ROCKIES LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR THE FIRST HALF OF NEXT WEEK REMAINS
TRICKY AS SURFACE FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES.
A BRIEF WARMUP IS STILL EXPECTED ON MONDAY AHEAD OF THE SHORTWAVE
MONDAY NIGHT. COOLER AIR WILL AGAIN DIVE SOUTHWARD TUESDAY INTO
WEDNESDAY...ALTHOUGH MODELS DISAGREE ON EXACTLY HOW FAR WEST THE
COLDEST AIR WILL REACH. THE GFS AND ECMWF BOTH HAVE WARMER AIR
MOVING BACK INTO THE REGION TOWARDS THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 956 AM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY MORNING.

&&

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

$$

SHORT TERM...JOHNSON
LONG TERM...15
AVIATION...POJORLIE