Area Forecast Discussion
Issued by NWS Bismarck, ND

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KBIS 171759
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1259 PM CDT SUN AUG 17 2014

.UPDATE...
ISSUED AT 1256 PM CDT SUN AUG 17 2014

THE NEWEST HIGH RESOLUTION MODELING...NAMELY THE 12 UTC WRF-ARW
AND NMM AND THE 15 AND 16 UTC HRRR INITIATE CONVECTION A BIT
FURTHER EAST THEN THEIR PREVIOUS ITERATIONS AND ADJUSTED POPS
ACCORDINGLY. SEE SPC DAY ONE OUTLOOK FOR OVERALL DETAILS.

UPDATE ISSUED AT 1011 AM CDT SUN AUG 17 2014

NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. THE 12 UTC NAM
AND 10-11 UTC HRRR ITERATIONS CONTINUE THE TREND OF THE 00 UTC
WRF-ARW AND NMM OF INITIATING POSSIBLY SEVERE CONVECTION ALONG A
SURFACE TROUGH ACROSS WESTERN NORTH DAKOTA JUST EAST OF HIGHWAY 85
AROUND 20 UTC...PROPAGATING EAST INTO THE LATE AFTERNOON AND
EVENING. THE 14 UTC RAP FORECASTS A MESOSCALE ENVIRONMENT
CHARACTERIZED BY DEEP LAYER SHEAR OF 25-30KTS AND ML CAPE OF
1500-2000 J/KG...SUPPORTIVE OF POSSIBLE SUPERCELLS WITH LARGE HAIL
BEING THE PRIMARY THREAT. RATHER WEAK LOW LEVEL SHEAR DOES
DIMINISH THE TORNADIC THREAT. WILL HAVE TO CLOSELY MONITOR
RAINFALL...ESPECIALLY FOR THOSE LOCATIONS HEAVILY IMPACTED ON
SATURDAY.

UPDATE ISSUED AT 625 AM CDT SUN AUG 17 2014

PRECIPITATION OVER FAR SOUTHWESTERN NORTH DAKOTA CONTINUES TO
DISSIPATE AS IT MOVES EAST...WHICH IS REFLECTED WELL IN ONGOING
POPS. SOME PATCHY FOG CONTINUES TO LOITER AROUND THE CWA...AND
WILL CONTINUE THRU THE EARLY MORNING. UPDATES HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM CDT SUN AUG 17 2014

HYDROLOGY AND THE RISK FOR SEVERE THUNDERSTORMS RULE THE SHORT TERM.

ADVISORIES FOR FLOODING HAVE ALL BEEN ALLOWED TO EXPIRE BASED ON
REPORTS FROM LAW ENFORCEMENT AND THE LACK OF RAIN OVER THE PAST
EIGHT HOURS OR SO IN THOSE ADVISORY AREAS.

HYDROLOGIC OUTLOOKS HAVE BEEN ISSUED FOR THE APPLE CREEK IN
BURLEIGH COUNTY...AND THE KNIFE RIVER BASIN...MAINLY THROUGH
MERCER COUNTY. APPLE CREEK WAS PERFORMING WELL BELOW EXPECTATIONS
WHILE THE KNIFE LOOKS LIKE IT WILL APPROACH MINOR FLOOD STAGE BUT
MAY NOT MAKE IT TO THAT DEFINED FLOOD LEVEL.

WILL BE REMOVING A FEW WESTERN COUNTIES FROM THE FLOOD WARNING IN
THE CENTRAL PART OF WESTERN NORTH DAKOTA...AND LIKELY EXTENDING
IN TIME THROUGH SUNDAY THE EASTERN PART OF THAT WARNING.

HIGH RESOLUTION MODELS DEVELOP THUNDERSTORMS IN EASTERN MONTANA
AND BRING THEM THROUGH WESTERN AND CENTRAL NORTH DAKOTA THIS
AFTERNOON IN RESPONSE TO A MID LEVEL SHORT WAVE APPROACHING...AND
THE CUT OFF MID LEVEL COOL POOL OVER SOUTHERN SASKATCHEWAN
INCREASING DEEP LAYER SHEAR. INSTABILITY AND CAPE BECOME
SUPPORTIVE OF SEVERE WEATHER ESPECIALLY BETWEEN 2 PM CDT AND 7 PM
CDT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 420 AM CDT SUN AUG 17 2014

LOW/TROF CONTINUES ITS EASTWARD PROGRESSION INTO MONDAY WITH PRECIP
CONTINUING TO TAPER FROM WEST TO EAST IN THE MORNING. IN THE
AFTERNOON...SOME RE-DEVELOPMENT MAY OCCUR AS THE AREA REMAINS UNDER
CYCLONIC FLOW...THOUGH MOST LOCATIONS SHOULD DRY OUT BY EVENING. A SHORT
LIVED DRY PERIOD IS EXPECTED THROUGH THE DAY ON TUESDAY AS A FAST
MOVING SHORT WAVE RIDGE MOVES THROUGH THE AREA. UPPER FLOW STARTS TO
SHIFT SOUTHWESTERLY TUESDAY EVENING AS RIDGE PUSHES EAST AND TROF
OVER THE WESTERN CONUS DEEPENS. CHANCES FOR PRECIPITATION THEN
STEADILY INCREASE THROUGH MID-WEEK AS A VARIETY OF WAVES MOVE
THROUGH THE FLOW...WITH THE GREATEST CHANCES COMING LATE WEDNESDAY
AS A SFC LOW/BOUNDARY SHIFTS THROUGH THE AREA. MODELS THEN HAVING
TROUBLE WITH THE TIMING OF INDIVIDUAL SYSTEMS FOR THE END OF THE
WEEK...BUT GENERAL CONSENSUS IS AN ACTIVE PATTERN SO WILL KEEP POPS
IN THE FORECAST. NEAR AVERAGE TEMPS EXPECTED THROUGH MID-WEEK WITH
MODELS ADVERTISING A COOLING TREND FOR THE END OF THE WEEK/WEEKEND.
WILL HAVE TO KEEP AN EYE ON THIS TO SEE HOW SIGNIFICANT OF A COOL
DOWN THIS WILL BE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1256 PM CDT SUN AUG 17 2014

A LINE OF POSSIBLY
SEVERE THUNDERSTORMS IS FORECAST TO DEVELOP ACROSS WESTERN NORTH
DAKOTA AROUND 20 UTC...AND MOVE EAST THROUGH THE EVENING. SEE TAFS
FOR EXPECTED TIMING AND IMPACTS TO EACH TERMINAL.

&&

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

$$

UPDATE...AYD
SHORT TERM...JPM
LONG TERM...JJS
AVIATION...AYD





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.