FXUS63 KBIS 072100
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
300 PM CST MON DEC 7 2009

.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT

TEMPERATURES ARE THE MAIN FORECAST CHALLENGE DURING THE SHORT TERM 
PERIOD. MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT ON THE FEATURES 
THIS PERIOD.

A BROAD TROUGH IN PLACE ACROSS NORTH AMERICA STRETCHES FROM THE 
WEST COAST OF THE US TO THE HUDSON BAY REGION.  AT THE 
SURFACE..BROAD AREA OF HIGH PRESSURE IS STRETCHING FROM THE FRONT 
RANGE OF THE CANADIAN ROCKIES IN CENTRAL ALBERTA INTO SASKATCHEWAN 
THIS AFTERNOON.

THE TWO PREVIOUSLY MENTIONED FEATURES PLAY A BIG ROLE IN THE WEATHER 
ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE SHORT TERM 
PERIOD. THE BROAD SURFACE HIGH CONTINUES TO SAG SOUTHEASTWARD 
TOWARDS NORTH DAKOTA ON TUESDAY AS A STRONG SHORTWAVE ROUNDS OF THE 
BASE OF THE TROUGH IN THE GREAT BASIN AND LIFTS INTO THE CENTRAL 
PLAINS. AS THIS SYSTEM MOVES OUT INTO THE PLAINS ON TUESDAY 
PRECIPITATION BEINGS SPREADING NORTHWARD INTO SOUTHWESTERN NORTH 
DAKOTA TONIGHT AND SPREADS EASTWARD DURING THE DAY TOMORROW WITH 
MOST OF THE PRECIPITATION IS CONFINED TO THE SOUTHERN MOST COUNTIES 
OF NORTH DAKOTA.  

BY TUESDAY EVENING THE SURFACE HIGH HAS MOVED INTO NORTH CENTRAL 
NORTH AND A DISTURBANCE MOVE THROUGH THE 500 HPA FLOW INTERACT WITH 
THE COLD MOIST AIR TO PRODUCE SOME SNOW SHOWERS 
TUESDAY NIGHT INTO WEDNESDAY MORNING.  A SURFACE TROUGH SLIDES 
THROUGH THE REGION ON WEDNESDAY NIGHT WHICH WOULD BE ACCOMPANIED BY 
10 TO 20 KNOT WINDS RESULTING IN WIND CHILLS APPROACHING ADVISORY 
CRITERIA.  HOWEVER EXTENSIVE CLOUD COVER ACROSS THE REGION MAY KEEP 
TEMPERATURES UP. THE ECMWF AND GFS DIFFER SLIGHTLY ON THE STRENGTH 
OF THE COLD AIR DROPPING SOUTHWARD BEHIND THE TROUGH ON WEDNESDAY 
NIGHT. 

.LONG TERM...FRIDAY THROUGH MONDAY
THE MODELS CONTINUE TO SHOW THE BROAD TROUGH OVER CENTRAL AND 
EASTERN CANADA SHIFTING NORTH AS ZONAL FLOW DEVELOPS ACROSS THE US. 
A SHORT WAVE MOVING AROUND THE UPPER LEVEL TROUGH AND THROUGH THE 
AREA FRIDAY NIGHT AND SATURDAY WILL BRING ONE LAST SHOT OF COLD AIR 
TO THE FORECAST AREA FOLLOWED BY A SLOW WARMING TREND. CONTINUE TO 
SEE LITTLE CHANCE OF SIGNIFICANT PRECIPITATION THROUGH THE LONG 
RANGE AS WEATHER SYSTEMS WILL CONTINUE TO MOVE SOUTH OF THE FORECAST 
AREA.

&&

.AVIATION...SATELLITE SHOWS ONLY A FEW PATCHES OF MID CLOUD OVER THE 
FORECAST AREA. THE GFS SHOWS WEAK SUBSIDENCE AT THE LOWER LEVELS SO 
IF ANY CLOUDS FORM TONIGHT IT WILL BE TO RADIATIONAL COOLING AND 
LIKELY TO BE IN THE MVFR TO IFR RANGE. CURRENT SURFACE REPORTS 
INDICATE SOME SCATTERED CLOUDS 15 HUNDRED AGL OR LOWER SO THERE IS 
LIKELY A MOIST LAYER ALOFT.  WILL TREND CLOUDS IN LATE TONIGHT INTO 
TUESDAY MORNING. 

&&

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

$$

DC/HW/TSW