000
FXUS63 KUNR 090525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1025 PM MST SAT MAR 8 2014

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 214 PM MST SAT MAR 8 2014

PAC AIRMASS WILL REMAIN OVER THE NORTHERN PLAINS
THROUGH THE PERIOD SUPPORTING WARM CONDITIONS OVER THE REGION AND
RECORD TO NEAR RECORD HIGHS AT RAPID CITY. SHORTWAVE RIDGE WILL PUSH
EAST IN THE PERIOD...WITH ROCKIES DOWNSLOPE AIR MOVING INTO THE
NORTHERN PLAINS. MORE SIG WAA WILL ENSUE TONIGHT INTO SUN WITH THE
MAIN LOBE OF PAC ORIGIN AIR ENTERING THE FA AFTER UNDERGOING
DOWNSLOPING PER THE ROCKIES. THERMAL RIDGE WILL TIME WITH THE
CENTRAL FA SUNDAY...WITH 14-16C NOTED OVER THE AREA AT H85 SUNDAY.
WEAK IMPULSE AND ASSOCIATED SFC REFLECTION WILL SUPPORT A WEAK SFC
TROUGH/COLD FRONT INTO THE NORTHERN ZONES SUNDAY NIGHT. NO SIG WX
EXPECTED IN THE PERIOD SAVE FOR INCREASING MID AND HIGH CLOUDS
EMANATING FROM AN APPROACHING NE PAC UPPER TROUGH.

TONIGHT...ONGOING PRESSURE FALLS WILL SUPPORT INCREASING BL FLOW WITH
GUSTY SW WINDS DEVELOPING OVER THE HIGH TERRAIN OF NE WY/DOWNWIND
THE PINE RIDGE/AND IN THE FAVORED DOWNSLOPING AREAS OF THE BLACK
HILLS. MSLP PROGS IN THE NAM SUGGEST A 4-5 MB PRESSURE DIFFERENTIAL
DEVELOPING OVER THE EASTERN BH AND FOOTHILLS...A GOOD SETUP FOR
DOWNSLOPING WINDS WITH 15 TO 25 KNOTS WINDS POSSIBLE AT TIMES. HAVE
INCREASED WINDS IN THESE AREAS. HAVE ALSO ADJUSTED TEMPS GIVEN
EXPECTED MIXING WHERE WINDS WILL INCREASE OVERNIGHT...BUMPING LOWS
UP THERE.

SUNDAY...HAVE BUMPED TEMPS UP GIVEN THERMAL PROFILES/EXPECTED MIXING
FROM INCREASING FLOW AHEAD OF THE SFC TROUGH/AND INSOLATION. HIGHS
IN THE 50S AND 60S WILL BE COMMON WITH SOME 70S EXPECTED IN THE LEE
OF THE BH AND INTO SCENTRAL SD. NEAR RECORD HIGHS ARE EXPECTED
AT EAST RAPID CITY AND THE RAPID CITY AIRPORT WITH CURRENT RECORDS
71 AND 73 RESPECTIVELY. MOISTURE ADV PER THE ARRIVING PAC NW UPPER
TROUGH WILL SUPPORT INCREASING CIRRUS OVER THE AREA...WITH SOME SUN
FILTERING POSSIBLE. NOT SURE ON THE DEGREE OF CIRRUS
THICKNESS...WHICH CAN ALWAYS BE PROBLEMATIC. HENCE...HAVE OPTED FOR
A 40 TO 50 PERCENT SKY COVER MENTION FOR NOW. SFC TROUGH WILL DROP
INTO THE AREA SUNDAY NIGHT WITH NW AREAS SEEING VEERING WINDS AND
PERHAPS A FEW MORE CLOUDS. NAM SOLUTIONS SUGGEST STRATUS AND DRIZZLE
IN THE FAR NW GIVEN ITS MORE ROBUST CAA PROFILES WITH APPRECIABLE LL
MOISTURE. HAVE REMAINED DRY ATTM. SUSTAINED WESTERLY FLOW WITH
FAIRLY WARM LL PROFILES WILL SUPPORT WARM CONDITIONS MOST PLACES
SUNDAY NIGHT...ESP IN THE EASTERN BH FOOTHILLS WHERE 40S WILL BE
COMMON.

&&

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 214 PM MST SAT MAR 8 2014

ABOVE AVERAGE TEMPS WILL CONTINUE INTO MONDAY BEFORE
THE NEXT COLD FRONT AND UPPER WAVE PUSH INTO THE AREA LATE-DAY
MONDAY BRINGING PRECIP CHANCES ALONG WITH A COOLING TREND. THE
GREATEST PRECIP CHANCES WILL BE MONDAY NIGHT INTO TUESDAY MORNING
WITH RAIN CHANGING TO SNOW AS COLDER AIR PUSHES IN FROM THE NORTH.
THERE ARE STILL SOME DIFFERENCES BETWEEN THE ECMWF AND GFS WITH THE
POSITION OF THE BAND OF PRECIP THAT SETS UP...BUT HAVE INCREASED
POPS TO CATEGORICAL ACROSS A LARGE PORTION OF THE CWA. UPPER RIDGING
WILL BUILD BACK IN FOR THE SECOND HALF OF THE WORK WEEK BRINGING DRY
CONDITIONS AND WARMING TEMPS. NEXT DISTURBANCE BRINGING PRECIP
CHANCES MAY APPROACH TOWARDS THE WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1024 PM MST SAT MAR 8 2014

VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. LOW LEVEL
WIND SHEAR IS EXPECTED THROUGH EARLY SUNDAY MORNING OVER SOUTHWEST
SD.

&&

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

$$

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