Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
631 AM CDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 620 AM CDT SUN AUG 30 2015

LATEST SATELLITE AND RADAR IMAGERY INDICATES AN AREA OF
FOG/STRATUS OVER THE SOUTHERN JAMES RIVER VALLEY INCLUDING
JAMESTOWN. ALSO AN AREA OF THUNDER OVER FAR NORTHEAST MONTANA
LIFTING INTO SOUTHERN SASKATCHEWAN. BOTH AREA COVERED IN THE
CURRENT FORECAST. HARD TO SEE ANY OTHER AREAS OF LOW STRATUS AS
HIGH CLOUDS CONTINUE TO TRACK OVER THE FORECAST AREA. BUT CAN NOT
RULE OUT A BRIEF REDUCTION IN VISIBILITY ANYWHERE EARLY THIS
MORNING IN SMOKE OR FOG. FOR THE UPDATE DID BUMP UP CLOUD COVER A
LITTLE GIVEN THE EXTENT OF HIGH LEVEL CLOUDS. OTHERWISE NO
SIGNIFICANT CHANGES TO THE CURRENT FORECAST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT SUN AUG 30 2015

CONCERNS IN THE SHORT TERM INCLUDE AREAS OF SMOKE THIS 
MORNING...THEN ATTENTION TURNS TO A COLD FRONTAL PASSAGE THIS 
AFTERNOON AND TONIGHT BRINGING CHANCES OF THUNDERSTORMS.

CURRENTLY...THE UPPER LEVEL RIDGE AXIS WAS OVER THE CENTRAL PART OF 
NORTH AMERICA...EXTENDING FROM THE SOUTHERN PLAINS TO THE DAKOTAS 
AND INTO MANITOBA/SASKATCHEWAN. MEANWHILE A LONGWAVE TROUGH WAS JUST 
OFF THE WEST COAST. UPPER LEVEL SHORTWAVE ENERGY IMPULSES MOVING 
NORTHEAST THROUGH THE FLOW ACROSS THE ROCKIES WAS ASSOCIATED WITH 
SCATTERED TO ISOLATED SHOWERS AND THUNDERSTORMS OVER CENTRAL MONTANA 
INTO SOUTH CENTRAL SASKATCHEWAN. AT THE SURFACE...BROAD LOW PRESSURE 
EXTENDED ALONG THE FRONT RANGE...INCLUDING A LOW PRESSURE 
TROUGH/FRONT OVER CENTRAL MONTANA. CIRRUS AND HIGH LEVEL MID CLOUDS 
MIXED WITH SMOKE FROM THE WESTERN FIRES CONTINUED TO STREAM 
NORTHEASTWARD ACROSS THE FRONT RANGE AND NORTHERN PLAINS. THE SMOKE 
THAT MIXED DOWN TO THE SURFACE IN FORCE ON SATURDAY STILL LINGERED 
ACROSS NORTH DAKOTA...THOUGH VISIBILITIES THIS MORNING WERE NOT AS 
LOW AS THEY WERE YESTERDAY. 

SMOKE AT THE SURFACE IS EXPECTED TO DISSIPATE LATER THIS MORNING AS 
WINDS BEGIN TO LINK UP WITH THE SOUTHERLY FLOW.  

THE WESTERN HIGH PRESSURE RIDGE AXIS IS FORECAST TO MOVE EASTWARD 
SLOWLY TODAY...ALLOWING SOUTHWESTERLY FLOW ALOFT TO ENTER WESTERN 
NORTH DAKOTA THIS AFTERNOON. IN RESPONSE...THE TROUGH/FRONT IN 
MONTANA WILL ALSO MOVE EAST AND ENTER WESTERN NORTH DAKOTA THIS 
AFTERNOON. THE STRONG THERMAL RIDGE WILL BE IN PLACE OVER THE STATE 
AND THIS THERMAL CAP (+12C TO +14C AT H700) SHOULD INHIBIT 
CONVECTION OVER WESTERN NORTH DAKOTA UNTIL LATER IN THE 
AFTERNOON...MAINLY ALONG AND BEHIND (WEST OF) THE SURFACE 
TROUGH/FRONT. AS THIS OCCURS...SOUTHERLY WINDS AHEAD OF THE 
TROUGH/FRONT WILL INCREASE TO 10 TO 15 MPH OVER WESTERN NORTH 
DAKOTA...AND TO AROUND 20 MPH OVER CENTRAL NORTH DAKOTA.

STILL LOOKING AT ANOTHER HOT DAY ACROSS ALL OF CENTRAL AND 
SOUTHWESTERN NORTH DAKOTA...WITH HIGHS IN THE MID TO UPPER 90S. IN 
THE NORTHWEST...TEMPERATURES BEHIND THE FRONT THIS AFTERNOON MAY 
ONLY REACH THE MID 80S TO LOWER 90S.

TONIGHT A SHORTWAVE IN THE UPPER LEVEL FLOW LIFTS NORTHEASTWARD 
ACROSS MONTANA AND WYOMING AND INTO NORTH DAKOTA. THE SURFACE 
TROUGH/FRONT IS FORECAST TO PROGRESS EASTWARD TO THE DEVILS LAKE 
BASIN AND JAMES VALLEY BY DAYBREAK MONDAY MORNING. THE THERMAL CAP 
SHOULD WEAKEN WITH TIME DURING THE EVENING HOURS AND THUNDERSTORMS 
SHOULD BECOME MORE WIDESPREAD ACROSS WESTERN AND CENTRAL NORTH 
DAKOTA...MORE SO ALONG THE SURFACE FRONT...BUT SCATTERED BEHIND IT 
AS WELL. WINDS WILL BECOME NORTHWESTERLY BEHIND THE FRONT...BRINGING 
COOLER AIR TO THE REGION. EXPECT LOWS TONIGHT TO RANGE FROM THE 60S 
IN CENTRAL NORTH DAKOTA TO THE MID TO UPPER 50S OVER THE WEST.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM CDT SUN AUG 30 2015

CONTINUED WARM TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES WILL 
HIGHLIGHT THE EXTENDED FORECAST PERIOD NEXT WEEK.

EXCEPT FOR A SCATTERED SHOWER OR ISOLATED THUNDERSTORM EAST MONDAY 
MORNING...COOLER AND DRIER CONDITIONS WILL BE IN STORE WITH
SUBSIDENCE BEHIND THE EXITING SHORTWAVE...HIGHS ARE EXPECTED TO BE
IN THE UPPER 70S TO MID 80S.

ON TUESDAY...WE DID ADD A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS 
FROM AROUND BISMARCK NORTH AND EAST INTO THE DEVILS LAKE BASIN AND 
JAMES RIVER VALLEY. DETERMINISTIC MODELS ARE ALL HINTING AT SOME 
POSSIBLE CONVECTION HERE GIVEN INCREASING INSTABILITY WITH DAYTIME 
HEATING COMBINED WITH AN INCREASING LOW LEVEL JET INTO EASTERN NORTH 
DAKOTA TUESDAY EVENING. 

BEYOND TUESDAY...OUR SOUTHWEST UPPER FLOW WILL CONTINUE THROUGH THE 
END OF THE EXTENDED PERIOD WITH TROUGHING ACROSS THE PACIFIC 
NORTHWEST AND RIDGING OFF TO OUR EAST. A QUASI-STATIONARY SURFACE 
TROUGH COMBINED WITH ANY EMBEDDED WAVES ALOFT WILL PROVIDE A FOCUS 
FOR MAINLY ISOLATED DAILY SHOWER AND THUNDERSTORM ACTIVITY. BEST
CHANCES STILL APPEAR TOWARDS THE END OF THE WORK WEEK AND INTO
NEXT WEEKEND. TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL THROUGH THE WORK WEEK WITH 80S TO LOW 90S FOR HIGHS THEN
COOLING A BIT INTO THE 70S AND 80S BY NEXT WEEKEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 620 AM CDT SUN AUG 30 2015

SMOKE REDUCING VSBYS AT THE SURFACE ACROSS PORTIONS OF WESTERN AND 
CENTRAL NORTH DAKOTA WILL CONTINUE THROUGH AT LEAST 15Z-16Z...WHEN 
SOUTHERLY WINDS INCREASE AND HELP MIX THE LOWER ATMOSPHERE. 

SOUTH WINDS INCREASING AFT 16Z AT ALL TAF SITES...STRONGEST AND 
GUSTY AT KBIS AND KJMS...AHEAD OF A COLD FRONT. THE COLD FRONT 
ENTERS WESTERN NORTH DAKOTA AROUND 18-21Z...THEN MOVES EASTWARD
SLOWLY REACHING CENTRAL NORTH DAKOTA AROUND 03Z. ISOLATED
THUNDERSTORMS POSSIBLE AROUND 21Z-00Z NEAR KISN/KDIK BUT WILL KEEP
MENTION OF VCSH BUT NOT VCTS IN THE TAFS FOR NOW SINCE LIKELIHOOD
IS LOW OF A TS RIGHT AT THE TAF SITE. CHANCES OF SHOWERS AND
THUNDERSTORMS INCREASE WITH TIME LATE SUNDAY NIGHT AS THE FRONT
MOVES EAST ACROSS THE STATE.

&&

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

$$

UPDATE...TWH
SHORT TERM...JV
LONG TERM...TWH
AVIATION...TWH

National Weather Service Glossary of Abbreviations