755 
FXUS63 KUNR 240354
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
854 PM MST THU JAN 23 2014

.UPDATE...
ISSUED AT 847 PM MST THU JAN 23 2014

03Z SURFACE ANALYSIS HAD A WARM FRONT FROM CENTRAL ND INTO THE
BLACK HILLS AND THEN SOUTH INTO SOUTHEAST WY. FAST MOVING ALBERTA
CLIPPER RACING SOUTH/SOUTHEAST FROM SK/MB INTO THE UPPER MIDWEST.
IT WILL PUSH THE WARM FRONT THROUGH THE CWA WITH STRONG WARM AIR
ADVECTION/RISING TEMPERATURES OVERNIGHT.

VERY TIGHT PRESSURE GRADIENT EXPECTED BEHIND WARM FRONT DURING
THE DAY FRIDAY WITH 50-60KT 850MB WINDS. QUESTION IS HOW MUCH MIXING
WILL THERE BE. LATEST 00Z NAM SHOWS NEUTRAL/WEAK COLD AIR
ADVECTION MIDDAY OVER THE CWA WITH TEMPERATURES ROCKETING INTO THE
UPPER 40S/LOWER 50S. THIS IS ABOUT 10F HIGHER THAN SKIN
TEMPERATURES SEEN ON BUFKIT SOUNDINGS. MOS GUIDANCE SUPPORTS THESE
HIGHER TEMPERATURES...WHICH WILL GREATLY INCREASE THE LIKELY-HOOD
OF MIXING DOWN HIGHER MOMENTUM AIR...MUCH LIKE RECENT EVENTS IN
THIS PATTERN OVER THE SD PLAINS. ANY SHOWERS THAT DEVELOP WITH
STEEP LOW LEVEL LAPSE RATES WILL FURTHER PROMOTE FULLY MIXED
BOUNDARY LAYER.

WILL UPGRADE HIGH WIND WATCH TO HIGH WIND WARNING FROM K2WX TO
KRAP WITH EVENING UPDATE.

&&

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 228 PM MST THU JAN 23 2014

CURRENT SURFACE MAP SHOW WARM FRONT THROUGH WESTERN NORTH DAKOTA
INTO CENTRAL SOUTH DAKOTA. STEADY OR RISING TEMPERATURES
OVERNIGHT AS STRONG LOW LEVEL WARM ADVECTION CONTINUES. 

STRONG SHORTWAVE DIVES SOUTH OUT OF CANADA...CROSSING THE DAKOTAS
OVERNIGHT. PRESSURE GRADIENT INCREASES ACROSS THE AREA...AND WILL
RESULT IN STRONG WINDS FOR FRIDAY. 850MB WINDS INCREASE TO
50-65KTS ACROSS WESTERN SOUTH DAKOTA. LACK OF PRESSURE RISES AND
LOW LEVEL COLD ADVECTION DURING THE DAY NOT AS FAVORABLE FOR HIGH
WINDS. FORECAST SOUNDINGS NOT MIXING DEEP ENOUGH BASED ON 2M
TEMPERATURES. HOWEVER...ONCE 2M TEMPERATURES ADJUSTED UPWARDS
BASED ON EXPECTED HIGHS...MIXING IS DEEP ENOUGH TO TAP INTO STRONG
WINDS ALOFT. WILL CONTINUE WITH HIGH WIND WATCH.

A FEW RAIN/SNOW SHOWERS POSSIBLE FRIDAY. BETTER CHANCE FOR
PRECIPITATION OVER THE BLACK HILLS HIGH AS FROUDE/RH FAVORABLE FOR
UPSLOPE ENHANCEMENT. COULD SEE A FEW INCHES OF SNOW OVER THE
HIGHER ELEVATIONS.  

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 228 PM MST THU JAN 23 2014

THE REGION WILL REMAIN IN FAST NORTHWEST FLOW ALOFT THROUGH THE 
WEEKEND INTO EARLY NEXT WEEK AS HIGH AMPLITUDE RIDGE PERSISTS ALONG 
THE PACIFIC COAST. ABOVE AVERAGE TEMPERATURES WILL CONTINUE SATURDAY 
AS WARMER AIR REMAINS OVER THE REGION. THE NEXT ARCTIC FRONT IS 
PROGGED TO CROSS THE CWA SUNDAY INTO SUNDAY NIGHT...BRINGING LIGHT 
SNOW AND FALLING TEMPERATURES TO MUCH OF THE AREA. IN 
ADDITION...WINDY CONDITIONS WILL REDUCE VISIBILITIES ACROSS THE 
SOUTH DAKOTA PLAINS. AFTER A BRIEF WARMUP ON TUESDAY...THE NEXT 
ARCTIC FRONT SLIDES THROUGH THE NORTHERN PLAINS...WITH ADDITIONAL 
CHANCES OF SNOW ON WEDNESDAY AND THURSDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 847 PM MST THU JAN 23 2014

VFR CONDITIONS EXPECTED TONIGHT. MVFR/IFR CONDITIONS WILL RETURN
TO NORTHEAST WYOMING...THE BLACK HILLS...AND NORTHWEST SOUTH
DAKOTA EARLY FRIDAY MORNING AS THE NEXT WEATHER SYSTEM BRINGS
LIGHT RAIN/SNOW SHOWERS TO THE AREA. STRONG NORTHWEST WINDS WILL DEVELOP
LATE FRIDAY MORNING THROUGH THE EARLY EVENING HOURS. WINDS GUSTS
GREATER THAN 50KTS WILL OCCUR FROM K2WX TO KRAP.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...HIGH WIND WARNING FROM 9 AM TO 7 PM MST FRIDAY FOR SDZ001-002-
     012-013-025-026-030-031-072-073.

     HIGH WIND WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR 
     SDZ014-032-043.

WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...7
LONG TERM...15
AVIATION...HELGESON