000
FXUS63 KUNR 150835
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
235 AM MDT SAT MAR 15 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 235 AM MDT SAT MAR 15 2014

UPPER LEVEL IMPULSE CONTINUES EAST ACROSS THE NORTHERN
PLAINS...WITH A SFC FRONTAL BOUNDARY STALLED NW-SE ACROSS THE FA. THE
ADVANCING UPPER LEVEL TROUGH WILL SUPPORT A FRONTAL WAVE ACROSS THE
REGION...WITH INCREASING CHANCES FOR RAIN AND SNOW. STRONGER
UPPER LEVEL TROUGH AND NOW ENTERING THE PAC NW WILL QUICKLY ADVECT
EAST TODAY...SUPPORTING A STRONG EAST PUSH OF THE WAVERING FRONTAL
BOUNDARY...FORCING THE FRONT BACK THROUGH THE REGION AS A WARM
FRONT TONIGHT INTO SUNDAY...WITH MUCH WARMER CONDITIONS RETURNING TO
THE REGION BY SUNDAY.

MAIN CONCERN TODAY IS THE CHANCE FOR PRECIP AS WELL AS PRECIP TYPE.
FORCING FOR LSA WILL INCREASE ACROSS THE AREA TODAY WITH THREE
CONCENTRATE AREAS OF LL CONVERGENCE/LIFT...LIFT ALONG THE PRIMARY
STALLED SFC FRONT ACROSS THE FA OVER THE NW SD ZONES TO SCENTRAL
SD...UPSLOPE LIFT ACROSS THE NORTHERN HILLS...AND LIFT ASSOCIATED
WITH THE MAIN PUSH OF CAA BEHIND THE FRONTAL WAVE THIS AFTERNOON AND
EVENING. GENERAL LSA HAS ALLOWED THE DEVELOPMENT OF POCKETS OF RAIN
ACROSS THE REGION THIS MORNING...WITH GROWING FRONTAL CIRCULATION LL
CONVERGENCE EXPECTED TO SUPPORT INCREASING COVERAGE OF PRECIP ACROSS
THE NW SD ZONES THROUGH AFTERNOON. STRENGTHENING NW FLOW OVER THE
NORTHERN HILLS WITH INCREASING FROUDE NUMBER AND MOISTURE WILL
SUPPORT INCREASING CHANCES FOR SNOW THERE...ESP THIS
AFTERNOON/EVENING. OTHER AREAS OF LIGHT RAIN EXPECTED ACROSS THE
REMAINDER OF THE FA...MAINLY DUE TO LARGE SCALE LIFT ASSOCIATED WITH
THE UPPER IMPULSE. HAVE ADJUSTED POPS TO HIGHLIGHT AREAS WITH THE
BEST DEEP LAYER LIFT. PRECIP WILL TRANSITION FROM RAIN TO SNOW ALL
AREAS THROUGH THE DAY...WITH THE NORTHERN HILLS AND THE FAR NE ZONES
SEEING MORE PERSISTENT SNOWS. THE ISSUE THEN BECOMES HOW MUCH SNOW.
GIVEN THAT SNOWFALL WILL BE DURING THE DAY WITH TEMPS AOA FREEZING
UNDER STRONG MID MARCH SUN...EXPECTING THERE TO BE SOME IMPEDANCE TO
SNOW ACCUMS ESP ON ROADWAYS. THE OTHER CONCERN IS CRYSTAL SIZE...ESP
IN THE NORTHERN HILLS WHERE THE MAJORITY OF LIFT REMAINS BELOW THE
DGZ UNTIL LATE AFTERNOON/EVENING WHEN PROFILES COOL ENOUGH.
HENCE...HAVE OPTED FOR THE LOW SIDE OF ACCUMS. NOT EXPECTING ANY
ISSUES IN AREAS THAT DO SEE SNOW...AND SO HELD OFF ON ANY HEADLINES.
ONE OTHER ISSUE WILL BE GUSTY NW WINDS OVER THE WY PLAINS. NW WINDS
OF 25 TO 35 MPH WITH GUSTS AROUND 45 EXPECTED THERE LATE MORNING
THROUGH AFTERNOON.

PRECIP WILL QUICKLY SHIFT SOUTH OUT OF THE REGION THIS
EVENING...WITH DRY WX EXPECTED ALL PLACES BY MIDNIGHT. WAA AND
HEIGHT RISES WILL ENSUE LATE TONIGHT...WITH TEMPS RESPONDING OVER
THE HIGHER TERRAIN AND BH FOOTHILLS. WAA WILL CONTINUE INTO SUNDAY
UNDER GENERALLY STRONG INSOLATION. GIVEN PROGGED THERMAL FIELDS AND
MIXING CONDITIONS...HAVE ADJUSTED TEMPS UP SOME SUNDAY...WITH MOST
PLACES SEEING 50S AND 60S UNDER DRY WX.

&&

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 235 AM MDT SAT MAR 15 2014

AN UPPER TROUGH WILL CROSS THE NORTHERN ROCKIES MONDAY
AND NORTHERN PLAINS MONDAY NIGHT. WITH MILD TEMPS CONTINUING
MONDAY...PRECIP WILL PUSH INTO THE AREA MONDAY AFTERNOON FIRST AS
RAIN. PRECIP WILL THEN INCREASE ACROSS THE AREA MONDAY NIGHT AS
COLDER AIR PUSHES WITH RAIN CHANGING TO SNOW. LIGHT TO MODERATE SNOW
ACCUMULATIONS ARE POSSIBLE BY TUESDAY MORNING...ESPECIALLY ACROSS
NORTHERN AND WESTERN PORTIONS OF THE CWA AS WELL AS THE BLACK HILLS.
COOL AND UNSETTLED WEATHER WILL CONTINUE THROUGH WEDNESDAY...WITH
DRIER AND WARMER CONDITIONS RETURNING FOR THE LATTER HALF OF THE
WEEK.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT
ISSUED AT 235 AM MDT SAT MAR 15 2014

WDSPRD MVFR/IFR CONDITIONS WILL DEVELOP ACROSS THE AREA
THIS MORNING AS SHRASN INCREASES IN COVERAGE. GUSTY NW WINDS WILL
ALSO DEVELOP...WITH GUSTS OVER 40KTS POSSIBLE ON THE
PLAINS...ESPECIALLY ACROSS NORTHEAST WY. CONDITIONS WILL GRADUALLY
IMPROVE FROM NORTHWEST TO SOUTHEAST THROUGH TONIGHT AS THE SYSTEM
EXITS THE REGION.

&&

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

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...13