759 
FXUS63 KBIS 212034
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
334 PM CDT THU MAR 21 2013

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...

MAIN FORECAST PROBLEM WILL BE LIGHT SNOW ACCUMULATIONS OVER WESTERN
AND CENTRAL NORTH DAKOTA TONIGHT THROUGH FRIDAY NIGHT. MODELS ARE
IN PRETTY GOOD AGREEMENT AND UTILIZED A GFS/ECMWF BLEND. ALTHOUGH
MODELS ARE SIMILAR...ONE BIG DIFFERENCE FROM EARLIER RUNS IS THE
CONTINUED SLOWING OF THE EASTWARD PROGRESSION OF THE BAROCLINIC
ZONE AND THE MAIN CHANGES THIS FORECAST PERIOD WILL BE SLOWING THE
EASTWARD PROGRESSION OF PRECIPITATION ACROSS THE CWA. OTHERWISE
THERE WERE NO SIGNIFICANT CHANGES TO THE FORECAST.

CURRENTLY...ARCTIC HIGH PRESSURE EXTENDED FROM MANITOBA THROUGH THE 
RED RIVER VALLEY...WITH LOW PRESSURE IN THE LEE OF THE ROCKIES FROM 
ALBERTA ACROSS EASTERN MONTANA/WYOMING. MODERATE SOUTHEAST WINDS
OF 15 TO 25 MPH IN WESTERN NORTH DAKOTA WERE IN RESPONSE TO THE
TIGHT SURFACE PRESSURE GRADIENT...BUT SHOULD CONTINUE TO DIMINISH
LATE THIS AFTERNOON. AN UPPER LEVEL TROUGH WAS CROSSING THE
ROCKIES AND EMERGING OVER CENTRAL MONTANA.

TONIGHT THROUGH FRIDAY...WITH THE ARCTIC HIGH SLOW TO MOVE EAST
AND THE UPPER LEVEL TROUGH DIGGING INTO THE CENTRAL AND SOUTHERN
ROCKIES...THERE IS LITTLE TO PUSH THE AREA OF PRECIPITATION IN
EASTERN MONTANA...INTO THE DAKOTAS UNTIL THE UPPER LOW TAKES SHAPE
OVER THE AREA LATE TONIGHT AND FRIDAY. BY THIS TIME...THINK THE
MOISTURE WILL BE EVEN MORE LIMITED. THEREFORE WE HAVE SLOWED THE
PROGRESSION OF PRECIPITATION INTO CENTRAL NORTH DAKOTA...PROBABLY
NOT ENOUGH...AND CUT BACK ON THE QPF AS THE SYSTEM PUSHES INTO THE
CENTRAL PORTION OF THE STATE.

AT THIS TIME IT LOOKS LIKE WE COULD SEE 1 TO 3 INCHES TOTAL
SNOWFALL TONIGHT THROUGH FRIDAY...FROM WILLISTON SOUTH TO
BEACH...DICKINSON...BOWMAN AND HETTINGER. TAPERING TO AROUND AN
INCH AS YOU GO EAST TO MINOT AND BISMARCK...AND LESS THAN AN
INCH FOR POINTS EAST. ANY ADDITIONAL SLOWDOWN WOULD FURTHER
DECREASE AMOUNTS...ESPECIALLY FROM BISMARCK AND MINOT EAST. THE
SOUTHWEST COULD SEE A MIX OF RAIN/SNOW ON FRIDAY AS THEY WARM INTO
THE MID TO UPPER 30S. OTHERWISE PRECIPITATION TYPE SHOULD BE SNOW.

BY FRIDAY NIGHT...THE MAIN UPPER SYSTEM IS DIVING SOUTH...BUT
THERE SHOULD BE ENOUGH UPPER LEVEL SUPPORT TO KEEP AT LEAST A
SLIGHT CHANCE OF PRECIPITATION OVER THE LOCAL AREA. LITTLE OR NO
ADDITIONAL ACCUMULATIONS ARE EXPECTED.

.LONG TERM...SATURDAY THROUGH NEXT THURSDAY...

THE LONG TERM PERIOD WILL BE DOMINATED BY A BLOCKING PATTERN OVER 
NORTH AMERICA RESULTING IN AN EXTENDED PERIOD OF TROUGHING OVER THE 
NORTHERN PLAINS. THIS WILL KEEP BELOW NORMAL TEMPERATURES THOUGH THE 
PERIOD...WITH HIGHS GENERALLY 10 TO 15 BELOW NORMAL. WITH LOWER 
HEIGHTS AND CYCLONIC FLOW ALOFT OVER THE DAKOTAS THROUGH THE WEEKEND 
KEPT A CHANCE OF SNOW IN THE FORECAST. KEPT THE REMAINDER OF THE 
FORECAST DRY MONDAY-THURSDAY WITH NO DISCERNIBLE PRECIPITATION 
PRODUCING FEATURES NOTED IN THE MODELS.

&&

.AVIATION...
VFR CONDITIONS THROUGH MID TO LATE EVENING FOR CENTRAL AND EASTERN 
TERMINALS INCLUDING KBIS-KMOT-KJMS. LOWERING CIGS WEST TO MVFR LATE 
THIS AFTERNOON INTO THIS EVENING AS A BAND OF LIGHT SNOW IS FORECAST 
TO DEVELOP. THIS BAND OF SNOW AND MVFR CIGS WILL CONTINUE EAST INTO 
CENTRAL NORTH DAKOTA IMPACTING KMOT-KBIS AROUND TO AFTER 
MIDNIGHT...AND INTO KJMS AFTER 12Z FRIDAY MORNING. 

&&

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

$$

SHORT TERM...TWH
LONG TERM/AVIATION...NH