FXUS63 KBIS 260940
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
340 AM CST THU NOV 26 2009

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...
THE LATEST WATER VAPOR IMAGERY LOOP SHOWS A PROGRESSIVE FLOW
PATTERN CONTINUING. NORTH DAKOTA IS DOMINATED BY AN UPPER RIDGE
CENTERED OVER UTAH WITH ITS RIDGE AXIS EXTENDING NORTH INTO
NORTHERN SASKATCHEWAN. WARM AIR ADVECTION EVIDENT WITH MID/HIGH
CLOUDS MOVING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING
PER LATEST IR IMAGERY LOOP. THE FOG/STRATUS IMAGERY SHOWS STRATUS
EXITING OUR FAR EASTERN AND SOUTHEASTERN ZONES...HOWEVER FOG HAS
DEVELOPED IN KJMS WHERE SKIES HAVE CLEARED AND LOW LEVEL MOISTURE 
REMAINS FROM LAST NIGHTS LIGHT SNOW ACCUMULATION. WILL METWATCH KJMS 
AND ALSO FURTHER SOUTH INTO OAKES BEFORE DECIDING HOW TO HANDLE FOG 
IN THE GRIDS. PROBABLY WILL MENTION PATCHY FOG AT THIS POINT.

THE LATEST MSAS SHOWS A LOW PRESSURE OVER SOUTHEASTERN ALBERTA
WITH A WARM FRONT FROM AROUND CUT BANK MONTANA TO JUST EAST OF 
BILLINGS. 3HR PRESSURE FALLS ARE MAXIMIZED OVER SOUTHERN 
SASKATCHEWAN AND HENCE THIS IS THE DIRECTION THE SURFACE LOW WILL 
MOVE. THE WARM FRONT CONNECTING FROM THE LOW WILL SLIDE THROUGH 
WESTERN NORTH DAKOTA THIS MORNING AND ACROSS CENTRAL NORTH DAKOTA BY 
MID/LATE AFTERNOON. UPWARD VERTICAL MOTION ASSOCIATED WITH THE WARM 
AIR ADVECTION WILL LEAD TO SCT AND AT TIMES A THIN BKN SKY CONDITION 
TODAY. WARM AIR ADVECTION WILL MAX OUT ON FRIDAY HENCE WILL HAVE OUR 
WARMEST TEMPERATURES. THE RIDGE FLATTENS DURING THE DAY FOR A MOSTLY 
TO PARTLY SUNNY SKY TREND. WINDS WILL REMAIN LIGHT THURSDAY AND 
FRIDAY.

THE NEXT CHANGE IN OUR WEATHER CAN BE SEEN ALONG 140W THIS MORNING
AS AN UPPER TROUGH PROGRESSES EAST. THIS TROUGH WILL SPLIT AS IT
MOVES ONSHORE FRIDAY WITH THE NORTHERN STREAM MOVING THROUGH NORTH
DAKOTA BEGINNING FRIDAY NIGHT. A COLD FRONT WILL TRACK ACROSS THE
FAR NORTH AND NORTHWEST FRIDAY NIGHT AND THEN INTO CENTRAL NORTH
DAKOTA SATURDAY AFTERNOON. WINDS WILL SHIFT TO THE NORTHWEST AND
BECOME BRISK (15-25MPH) BEHIND THE FRONT WITH A SLIGHT CHANCE FOR
RAIN AND SNOW SHOWERS. THE NAM 925MB-850MB RH FIELD SHOWS AN AREA
OF LOW CLOUDS DEVELOPING OVER EASTERN SASKATCHEWAN AND MANITOBA
WHICH MOVE INTO CENTRAL NORTH DAKOTA LATE SATURDAY NIGHT. HAVE
MADE LITTLE CHANGE TO PREVIOUS GRIDS FOR PRECIPITATION CHANCES
FRIDAY NIGHT THROUGH SATURDAY NIGHT. TEMPERATURES WILL BE WARMEST
FRIDAY WITH HIGHS AROUND 40F IN OUR NORTHEAST ZONES TO UPPER 50S
ACROSS THE SOUTHWEST. DRY TODAY THROUGH FRIDAY SO NO THANKSGIVING 
WEATHER TRAVEL CONCERNS ACROSS WESTERN AND CENTRAL NORTH DAKOTA.

.LONG TERM...SUNDAY THROUGH THURSDAY...

SOME SUBTLE DIFFERENCES IN THE FINER DETAILS BETWEEN THE 
GEM...GFS...AND ECMWF BUT OVERALL EVOLUTION OF THE PATTERN IS THE 
SAME.

MODELS PLACE RIDGING ACROSS THE WESTERN UNITED STATES WITH A TROUGH 
IN THE GULF OF ALASKA FOR THE START OF THE LONG TERM. THE 500 HPA 
RIDGE SLOWLY MOVES EASTWARD SUNDAY NIGHT INTO TUESDAY. SOME WEAK 
ENERGY GETS KICKED OUT OF THE GULF OF ALASKA TROUGH SUNDAY NIGHT 
INTO MONDAY WITH LITTLE AGREEMENT BETWEEN THE THREE MODELS WITH THIS 
SYSTEM BUT THE GEM APPEARS TO BE AN OUTLIER MOVING IT THROUGH 
NORTHWEST AND CENTRAL NORTH DAKOTA WHILE THE GFS AND ECMWF MOVE IT 
THROUGH NORTHEAST NORTH DAKOTA. THE GULF OF ALASKA TROUGH PUSHES 
DOWN THE RIDGE AND MOVES SOUTHEASTWARD INTO THE NORTHERN PLAINS BY 
TUESDAY. THIS SYSTEM DRIVES A POWERFUL COLD FRONT THROUGH NORTH 
DAKOTA DURING THE DAY ON TUESDAY BRINGING SOME NOTICEABLY COLDER 
CANADIAN AIR INTO THE REGION FOR THE END OF THE LONG TERM 
REPRESENTED BY A 1000 TO 500 HPA THICKNESS DROP FROM 544 DM TO 514 
DM. MOST OF THE PRECIPITATION IS ALONG AND BEHIND THE COLD FRONT IN 
THE COLDER AIR WHICH WOULD INDICATE THE POTENTIAL FOR MAINLY 
SNOWFALL.  MODELS ARE SHOWING GENERALLY LIGHT QPF WITH THE TROUGH.

THE GULF OF ALASKA TROUGH BECOMES A CLOSED LOW OVER THE NORTHERN 
GREAT LAKES PLACING WESTERN AND CENTRAL NORTH DAKOTA UNDER NORTHWEST 
FLOW ALOFT WHICH IS GENERALLY INDICATES A MORE ACTIVE WEATHER 
PATTERN BY THE END OF THE LONG TERM.

&&

.AVIATION...

SURFACE HIGH PRESSURE RIDGE AXIS WAS OVER THE EASTERN DAKOTAS THIS 
MORNING. LIGHT WINDS AND CLEARING SKIES OVER THE RIDGE 
AXIS...COMBINED WITH SURFACE MOISTURE FROM AROUND AN INCH OF 
SNOWFALL YESTERDAY...WAS PRODUCING SOME PATCHY FOG. MAY SEE SOME 
EARLY MORNING FOG NEAR KJMS...OTHERWISE MAINLY SCT-BKN HIGH CIRRUS 
CLOUDS AND SCT MID CLOUDS TODAY. LIGHT WINDS WILL BECOME SOUTH WITH 
THE APPROACH OF A SURFACE TROUGH...THEN TURN SOUTHWEST AS THE 
SURFACE TROUGH MOVES FROM WESTERN ND AROUND NOON TOWARDS CENTRAL ND 
THIS THURSDAY EVENING.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

KS/JV/DC