Area Forecast Discussion
Issued by NWS Rapid City, SD

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699
FXUS63 KUNR 021850
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1150 AM MST TUE FEB 2 2016

.UPDATE...
ISSUED AT 1150 AM MST TUE FEB 2 2016

SURFACE ANALYSIS SHOWS STACKED LOW PRESSURE SYSTEM CENTERED OVER
NORTH CENTRAL KS...MOVING NORTHEASTWARD INTO EASTERN NEB. A COLD
FRONT STRETCHES ACROSS NORTHERN SD INTO EASTERN MT. THE NORTHERN
PORTION OF THE STORM SYSTEM TO THE SOUTH CONTINUES TO BRING SOME
SNOWFALL TO MOSTLY THE BLACK HILLS AREA AND SOUTHERN SD AT THIS
TIME. OUTER BAND OF SNOWFALL WITH THE SYSTEM IS MOVING ACROSS
SOUTH CENTRAL SD NOW...WITH LIGHT TO MODERATE SNOWFALL. ONE TO TWO
INCHES OF SNOW IS EXPECTED ACROSS FAR SOUTH CENTRAL SD THROUGH THE
AFTERNOON...WITH PATCHY BLOWING SNOW POSSIBLE INTO THE AFTERNOON
AS NORTHERLY WINDS INCREASE THERE.

FURTHER NORTHWEST INTO THE BLACK HILLS AREA...THE COMBINATION OF
UPSLOPE NORTHEASTERLY FLOW...STEEP LAPSE RATES...AND A FAVORABLE
FROUDE NUMBER HAVE HELPED TO PRODUCE LIGHT TO MODERATE SNOW
SHOWERS THIS MORNING...ESPECIALLY OVER THE FOOTHILLS AND NORTHERN
AND EASTERN SLOPES OF THE BLACK HILLS. TWO TO SIX INCHES OF SNOW
HAS BEEN REPORTED IN MANY AREAS OF THE BLACK HILLS SINCE LAST
NIGHT...WITH THE HIGHER AMOUNTS GENERALLY IN THE SOUTHERN BLACK
HILLS OVERNIGHT. THIS ACTIVITY IS STARTING TO DECREASE SOME IN
COVERAGE AND INTENSITY NOW...WITH ANY ADDITIONAL ACCUMULATIONS
MAINLY AN INCH OR LESS THROUGH THE AFTERNOON.

HAVE UPDATED TO LET THE WINTER WEATHER ADVISORY EXPIRE FOR
SOUTHERN PORTIONS OF NORTHEAST WY AND FALL RIVER CO IN SD. WILL
KEEP ADVISORY GOING FOR THE SOUTHERN BLACK HILLS INTO THE
AFTERNOON...LIKELY CANCELING IT WITH THE AFTERNOON FORECAST
PACKAGE. LINGERING SNOW WILL TAPER OFF IN MOST AREAS BY EARLY
EVENING. TEMPERATURES WILL REMAIN NEARLY STEADY THROUGH THE
AFTERNOON WITH CLOUD COVER HANGING AROUND...20S TO AROUND 30
DEGREES.

&&

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
ISSUED AT 216 AM MST TUE FEB 2 2016

UPPER LEVEL ANALYSIS HAS VIGOROUS CLOSED LOW OVER SOUTHWEST KANSAS
WITH BROAD TROF ACROSS MUCH OF THE WESTERN CONUS. SKIES ARE CLOUDY
ACROSS THE NORTHERN PLAINS WITH LIGHT SNOW FALLING ACROSS MUCH OF
NORTHEAST WYOMING AND SOUTHWESTERN SOUTH DAKOTA. AT THE
SURFACE...LOW PRESSURE IS LOCATED ACROSS SOUTH CENTRAL KANSAS AND
HIGH PRESSURE RESIDES ACROSS SOUTH CENTRAL CANADA INTO THE FAR
NORTHERN PLAINS. TEMPERATURES AT 2AM ACROSS THE FORECAST AREA ARE
GENERALLY IN THE MID TO UPPER 20S...WITH NORTH TO NORTHEAST WINDS
OF 10 TO 15 MPH.

TODAY...UPPER LOW WILL CONTINUE TO SHIFT NORTHEAST INTO EASTERN
NEBRASKA BY LATE THIS AFTERNOON...AS SURFACE HIGH PRESSURE HOLDS
TRUE ACROSS SOUTHERN CANADA INTO NORTH DAKOTA. SNOW WILL BE MOST
WIDESPREAD ACROSS FAR SOUTHERN SOUTH DAKOTA TODAY...ESPECIALLY
ACROSS SOUTH CENTRAL SOUTH DAKOTA...AS THE SURFACE LOW TRACKS
FROM CENTRAL KANSAS TO NORTHWEST MISSOURI DURING THE DAY.
LINGERING SNOW ELSEWHERE WILL TAPER OFF BY LATE AFTERNOON.
HOWEVER...SNOW SHOWERS ARE LIKELY OVER THE CENTRAL AND SOUTHERN
BLACK HILLS DURING THE MIDDAY AND AFTERNOON HOURS AS INSTABILITY
INCREASES ON THE BACK SIDE OF THE SYSTEM. CURRENT WINTER WEATHER
ADVISORY IS DUE TO END LATE THIS MORNING...BUT WITH THE
INSTABILITY SNOW SHOWERS ACROSS THE BLACK HILLS...THE ADVISORY FOR
THE SOUTHERN BLACK HILLS WILL EXTEND INTO THE AFTERNOON. HIGHS
TODAY WILL MAINLY BE IN THE 20S. BRISK NORTHERLY WINDS CAN BE
EXPECTED OVER SOUTH CENTRAL SOUTH DAKOTA IN THE AFTERNOON ON THE
BACK SIDE OF THE SYSTEM. LOW CHANCES FOR SNOW WILL LINGER INTO
TONIGHT OVER PORTIONS OF THE AREA AS A WEAK SHORTWAVE IN NORTHWEST
FLOW MOVES ACROSS THE AREA. LOW TEMPERATURES WILL FALL INTO THE
TEENS.

WEDNESDAY...UPPER LEVEL LOW WILL LIFT INTO THE GREAT LAKES REGION
AS THE BROAD WESTERN TROF SHIFTS ACROSS THE NORTHERN PLAINS. SKIES
WILL REMAIN MOSTLY CLOUDY ACROSS MUCH OF THE AREA...WITH SOME
CLEARING POSSIBLE LATE IN THE DAY ACROSS WESTERN AREAS. WEAK
INSTABILITY WILL REMAIN ACROSS THE BLACK HILLS...SO A CHANCE OF
SNOW SHOWERS REMAINS IN THE FORECAST. HIGH TEMPERATURES WILL
REMAIN BELOW AVERAGE...IN THE MID 20S TO MID 30S. MAIN UPPER TROF
CONTINUES TO TREK EAST WEDNESDAY NIGHT...WITH RIDGING CROSSING THE
ROCKIES LATE WEDNESDAY NIGHT. SKIES WILL BE VARIABLY CLOUDY WITH
LOW TEMPERATURES FALLING INTO THE TEENS ONCE AGAIN.

.LONG TERM...THURSDAY THROUGH MONDAY
ISSUED AT 216 AM MST TUE FEB 2 2016

THURSDAY/FRIDAY...UPPER LEVEL RIDGE OVER THE WEST COAST WILL
BRING NORTHWEST FLOW ALOFT OVER THE CWA. A COUPLE OF WAVES WILL
MOVE THROUGH...WITH THE NORTHERN WAVE BEING MOISTURE STARVED AND
THE WAVE TO THE WEST TRENDING WESTWARD AND THUS TOO FAR AWAY FROM
MENTIONABLE POPS. TEMPERATURES WILL BE SEASON. UPPER/THERMAL RIDGE
PEAKS SATURDAY WITH PLEASANT TEMPERATURES IN THE 40S FOR MANY
AREAS. LONG RANGE GUIDANCE THEN STARTS TO DIVERGE WITH AN ARCTIC
AIR OUTBREAK EXPECTED OVER PARTS OF THE NORTHERN PLAINS/MIDWEST BY
EARLY NEXT WEEK. OPERATIONAL GFS BY FAR THE COLDEST OF ALL
GUIDANCE WITH HIGHS TUESDAY FORECAST AT 19F...WITH OTHER MEMBERS
SHOWING AS HIGH AS 56F...WHICH IS MUCH CLOSER TO ECMWF GUIDANCE.
NEEDLESS TO SAY...WILL USE AVERAGE VALUES GIVEN UNCERTAINTY. VERY
WINDY CONDITIONS LOOK FAIRLY CERTAIN...SO WILL HIGHLIGHT IN
MORNING HWO.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY
ISSUED AT 1025 AM MST TUE FEB 2 2016

-SN WILL LINGER ACROSS MUCH OF THE AREA TODAY INTO THIS EVENING.
MVFR CIGS ARE EXPECTED AROSS MUCH OF WESTERN SOUTH DAKOTA WITH
AREAS OF IFR CONDITIONS OVER MUCH OF NORTHEASTERN WYOMING...THE
BLACK HILLS AREA AND SOUTHWESTERN INTO SOUTH CENTRAL SOUTH DAKOTA.
CONDITIONS WILL IMPROVE FROM NORTHWEST TO SOUTHEAST BEGINNING THIS
EVENING WITH A TREND TOWARD VFR CONDITIONS BY WEDNESDAY MORNING.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR SDZ029.

WY...NONE.
&&

$$

UPDATE...26
SHORT TERM...15
LONG TERM...HELGESON
AVIATION...10



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