FXUS63 KBIS 062101
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
301 PM CST SUN DEC 6 2009

.SYNOPSIS...
COLD ARCTIC HIGH PRESSURE RIDGE BUILDING SOUTHEAST FROM LEE OF
CANADIAN ROCKIES TO NORTHERN PLAINS. AREAS OF FLURRIES AND LIGHT
SNOW TRAVERSING FORECAST AREA VERY DIFFICULT TO SPOT ON RADAR OR
ON SATELLITE IMAGERY. TEMPERATURES REMAIN WELL BELOW NORMAL. 

&&

.SHORT TERM...
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM. THE MAIN 
FORECAST CONCERNS THROUGH THE PERIOD ARE DAILY TEMPERATURES AND 
CHANCES OF PRECIPITATION.

A SHORT WAVE 500 HPA RIDGE IS EXITING TO THE EAST THIS EVENING WITH 
A DEEP TROUGH ACROSS MUCH OF THE WESTERN UNITED STATES.  NORTH 
DAKOTA IS UNDER WEAK NORTHERLY FLOW AT THE SURFACE WITH A STRONG 
1045 MB SURFACE HIGH IN ALBERTA. ABUNDANT MOISTURE IS PRESENT AT THE 
SURFACE WHICH HAS LED TO OVERCAST SKIES WITH OCCASIONAL SNOW SHOWERS 
ACROSS MUCH OF WESTERN AND CENTRAL NORTH DAKOTA. 

A BROAD TROUGH STAYS IN PLACE ACROSS THE WESTERN US THROUGH THE 
SHORT TERM PERIOD WITH MULTIPLE DISTURBANCES MOVING THROUGH THE 
TROUGH TO OUR SOUTH. AT THE SURFACE...THE PREVIOUSLY MENTIONED 
SURFACE HIGH MOVES TO THE SOUTHEAST THROUGH TUESDAY PULLING COLDER 
ARCTIC AIR SOUTHWARD THROUGH WEDNESDAY. AS THIS OCCURS...A STRONGER 
DISTURBANCE MOVING THROUGH THE TROUGH EJECTS OUT INTO THE SOUTHERN 
PLAINS AND SPREADS PRECIPITATION NORTHWARD INTO SOUTHERN NORTH 
DAKOTA MAINLY SOUTH OF I-94. THIS WOULD BRING ONLY A SLIGHT CHANCE OF 
SNOW SHOWERS TO SOUTHERN PORTIONS OF NORTH DAKOTA TUESDAY MORNING 
INTO WEDNESDAY. 

EXPECT TEMPERATURES TO REMAIN WELL BELOW NORMAL FOR TIME OF YEAR AS 
AR CTIC AIR FLOWS SOUTHWARD INTO NORTH DAKOTA THROUGH WEDNESDAY. 850 
HPA TEMPERATURES ARE GENERALLY AROUND -20*C WITH -24*C AIR MOVING 
INTO NORTHERN NORTH DAKOTA BY TUESDAY MORNING WITH THE SURFACE HIGH. 
LIGHT WINDS THROUGH THE PERIOD SHOULD KEEP WIND CHILL VALUES FROM 
REACHING ADVISORY CRITERIA.

.LONG TERM...
THE MODELS CONTINUE TO BE IN AGREEMENT ON THE LARGE SCALE FEATURES 
AND TREND...MORE OR LESS KEEPING THE FORECAST AREA COLD 
INITIALLY...WITH SOME WARMING TOWARD THE END OF THE FORECAST PERIOD. 
THURSDAY WILL BEGIN WITH A SHARP UPPER LEVEL RIDGE OFF THE BRITISH 
COLUMBIA COAST WITH A SUBTROPICAL JET RUNNING ACROSS NORTHERN MEXICO 
AND A BROAD AREA OF LOW PRESSURE OVER MOST OF CENTRAL AND EASTERN 
CANADA.  BY SUNDAY THE MODELS LIFT THE JET NORTH SETTING UP ZONAL 
FLOW ACROSS THE WESTERN AND CENTRAL US WHILE SHIFTING THE UPPER 
LEVEL LOW NORTH AND EAST.  EVEN WITH THE CHANGE SEE LITTLE CHANCE OF 
SIGNIFICANT PRECIPITATION AS ANY SIGNIFICANT SHORT WAVES WILL PASS 
SOUTH OF THE FORECAST AREA. TEMPERATURES WILL BEGIN COLD...BUT WITH 
A SLOW WARMING TREND THROUGH THE END OF THE LONG TERM. 

&&

.AVIATION...
IT HAS BEEN ANOTHER DAY OF LOW CLOUDS AND REDUCED 
VISIBILITIES IN LIGHT SNOW AND FLURRIES.  CURRENT SATELLITE SHOWS A 
BROAD AREA OF CLOUDS COVERING THE REGION ON THE EAST AND SOUTH SIDE 
OF AN ARCTIC HIGH IN CENTRAL ALBERTA SO DON'T EXPECT ANY IMPROVEMENT 
THROUGH THE NIGHT. IN FACT...IF THE NAM RH TREND IS CORRECT... 
SHOULD NOT SEE ANY SIGNIFICANT CHANGE UNTIL THE CENTER OF THE ARCTIC 
HIGH PRESSURE SYSTEM MOVES THROUGH THE AREA TUESDAY NIGHT AND 
WEDNESDAY.  

&&

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

$$

DC/HW/TSW