Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 302104
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
404 PM CDT THU OCT 30 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 404 PM CDT THU OCT 30 2014

LOW LEVEL STRATUS AND FREEZING DRIZZLE POTENTIAL TONIGHT...AND
STRONG WINDS FRIDAY HIGHLIGHT THE SHORT TERM.

VISIBLE SATELLITE THROUGH 2015 UTC SHOWS THAT THE STRATUS HAS
ERODED ACROSS THE TURTLE MOUNTAINS...AND DEVILS LAKE BASIN INTO
THE UPPER JAMES RIVER VALLEY. THIS IS GENERALLY ON TRACK...IF NOT
JUST A BIT SLOWER WHEN COMPARED TO THE LOW LEVEL RH FIELDS ON THE
17 THROUGH 19 UTC RAP AND HRRR ITERATIONS. STRATUS EROSION WILL
CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING AS LOW LEVEL
SUBSIDENCE INCREASES WITH THE BUILDING SURFACE HIGH. THERE ARE SOME
INDICATIONS IN THE RAP/HRRR AND OBSERVED SATELLITE TRENDS THAT THE
STRATUS MAY LINER ALONG AND WEST OF HIGHWAY 85 THROUGH MUCH OF THE
NIGHT. THUS...WITH SUNDOWN STRATUS BUILD DOWN IS
POSSIBLE...LEADING TO FOG AND POTENTIALLY PATCHY FREEZING DRIZZLE
WITH SATURATION WARMER THAN -10C ACROSS THE SOUTHWEST.
OTHERWISE...A COLD NIGHT IS EXPECTED FOR STRATUS FREE AREAS WITH
LIGHT WINDS AND CLEAR SKIES IN THE SURFACE HIGH AND LOWS IN THE
TEENS.

FOR FRIDAY...ISSUED A WIND ADVISORY FOR THE SOUTHWEST FROM 18-00
UTC. STRONG SOUTHEASTERLY WIND ARE FORECAST AS THE PRESSURE
GRADIENT INCREASES BETWEEN THE DEPARTING SURFACE HIGH PROPAGATING
INTO THE UPPER MISSISSIPPI VALLEY AND THE STATIONARY LEE FRONT
ACROSS MONTANA AND WYOMING. 0.5 KM WINDS INCREASE TO 50 KTS BY 00
UTC ACROSS MUCH OF THE WESTERN AND CENTRAL NORTH DAKOTA.
HOWEVER...MIXING HEIGHTS ARE RATHER SHALLOW GIVEN THE LOW LEVEL
WARM AIR ADVECTION INDUCED INVERSION. THUS...THE HIGHER TERRAIN OF
THE SOUTHWEST HAS THE BEST CHANCE OF TAPING INTO THE STRONG WINDS
AT THE BASE OF THE INVERSION. SHOULD MIXING HEIGHTS BE GREATER
THAN FORECAST...AN EXPANSION IN TIME AND AREA OF THE ADVISORY MAY
BE POSSIBLE.


.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 404 PM CDT THU OCT 30 2014

MAIN IMPACTS IN THE EXTENDED...WINDY CONDITIONS FRIDAY
EVENING...RAIN/SNOW MONDAY.

VERY WINDY CONDITIONS ARE FORECAST TO
DEVELOP OVER SOUTHWESTERN NORTH DAKOTA FRIDAY AFTERNOON. WARM AIR
ADVECTION...COMBINED WITH LARGE PRESSURE FALLS AHEAD OF A LOW
PRESSURE CENTER IN EASTERN MONTANA...WILL BRING IN GUSTY WINDS
AROUND 40 MPH. WINDS SHOULD DIMINISH BY SATURDAY AS THE PRESSURE
GRADIENT WEAKENS ACROSS NORTH DAKOTA.

THE LATEST GUIDANCE (12 UTC GFS/ECMWF/SREF/NAM) ARE IN GOOD
AGREEMENT IN THE TIME AND PLACEMENT OF THE SUNDAY/MONDAY SHORTWAVE
TROUGH. THE BULK OF THE PRECIPITATION SHOULD REMAIN WEST OF NORTH
DAKOTA SUNDAY. AS THE SHORTWAVE ENTERS SASKATCHEWAN AND MANITOBA
SUNDAY NIGHT INTO MONDAY...WRAP AROUND MOISTURE COULD BRING IN A
CHANCE OF RAIN OR SNOW ACROSS THE NORTH MONDAY MORNING.

ANOTHER SHORTWAVE IS FORECAST TO SWING OUT OF SASKATCHEWAN AND
ENTER NORTH DAKOTA TUESDAY NIGHT/WEDNESDAY MORNING. THE ECMWF IS A
BIT FURTHER NORTH WITH PRECIPITATION THAN THE GFS. IF THE TRACK ON
THE ECMWF HOLDS TRUE THEN VERY LITTLE IF ANY PRECIPITATION WILL
IMPACT NORTH DAKOTA WITH THIS PARTICULAR SHORTWAVE TROUGH. THE
ECMWF IS ALSO WARMER THAN THE GFS...POINTING TO ALL RAIN PRECIP
RATHER THAN THE RAIN/SNOW MIX OF THE GFS. RIGHT NOW ONLY A SLIGHT
CHANCE FOR PRECIPITATION WAS ADDED TO THE FORECAST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 404 PM CDT THU OCT 30 2014

MVFR TO IFR STRATUS WILL CONTINUE TO ERODE ACROSS ALL BUT FAR
WESTERN NORTH DAKOTA THIS EVENING. THIS INCLUDES KDIK AND POSSIBLY
KISN...WHERE MVFR TO IFR CEILINGS MAY CONTINUE THROUGH MUCH OF THE
NIGHT...WITH SOME FOG AND PATCHY FREEZING DRIZZLE POSSIBLE WITH
STRATUS BUILD DOWN. STRONG SOUTHEAST WINDS ARE FORECAST AREA WIDE
FRIDAY...THE STRONGEST BEING ACROSS THE SOUTHWEST WHERE GUSTS IN
EXCESS OF 40 KTS ARE POSSIBLE AT KDIK.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TO 6 PM MDT FRIDAY FOR NDZ031>033-040-
041-043-044.

&&

$$

SHORT TERM...AYD
LONG TERM...AJ
AVIATION...AYD








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