Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 021750
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1250 PM CDT THU JUL 2 2015

.UPDATE...
ISSUED AT 1243 PM CDT THU JUL 2 2015

THE FORECAST FOCUS TODAY IS ON THUNDERSTORMS WITH HEAVY RAIN.

SINCE THE INITIAL PUSH OF THUNDERSTORMS ASSOCIATED WITH A ROBUST MID
LEVEL SHORTWAVE PUSHED INTO SOUTH DAKOTA...WE HAVE SEEN SEVERAL LOW-
TOPPED THUNDERSTORMS REMAIN QUASI-STATIONARY BETWEEN US 83 AND THE
JAMES RIVER BASIN JUST EAST OF A LINGERING SURFACE TROUGH. THE
SHALLOW NATURE OF THESE THUNDERSTORMS WITH VERY LITTLE LIGHTENING
SUGGESTS THAT WARM RAIN PROCESSES ARE PRESENT. REPORTS THUS FAR
HAVE NOT INDICATED ANYTHING MORE THAN MINOR FLOODING...WITH
ACCUMULATIONS ALL LESS THAN 2 INCHES...BUT EACH THUNDERSTORM WILL
NEED TO BE MONITORED.

DIURNALLY ENHANCED CONVECTION IS ALSO FORECAST BY THE 12 UTC WRF
ARW/WRF NMM AND THE LAST FEW RUNS OF THE HRRR ACROSS SOUTH
CENTRAL/SOUTHEAST NORTH DAKOTA. THERE IS STRONG CONSENSUS THAT
CONVECTION WILL DRASTICALLY REDUCE BY 02 UTC THIS EVENING.

BASED ON THE FLOW REGIME...VISIBILITY REDUCTIONS DUE TO SMOKE FROM
FIRES IN NORTHERN ALBERTA WILL LINGER ACROSS THE AREA THROUGH
TOMORROW AFTERNOON.

UPDATE ISSUED AT 919 AM CDT THU JUL 2 2015

QUICK UPDATE TO POPS AS HEAVY SHOWERS AND ISOLATED THUNDERSTORMS
CONTINUE TO DEVELOP ACROSS THE JAMES RIVER VALLEY.

LATEST HRRR SHOWS SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING
ACROSS MOST OF WESTERN AND CENTRAL NORTH DAKOTA BY THIS AFTERNOON
AND ACTIVITY ACROSS THE JAMES VALLEY PERSISTING THROUGH THE
AFTERNOON HOURS. FOG SHOULD BEGIN LIFTING ACROSS MOST OF THE AREA
THIS MORNING...HOWEVER...HAZE IS LIKELY THROUGH THE DAY. SOME WARM
RAIN PROCESSES WERE NOTED WITH SHOWERS ACROSS THE JAMES VALLEY.
RADAR ESTIMATES AROUND 2 INCHES HAVE FALLEN ACROSS PORTIONS OF
EMMONS AND KIDDER COUNTIES JUST WITHIN THE PAST HOUR. AS A RESULT
A FLOOD ADVISORY HAS BEEN ISSUED

UPDATE
ISSUED AT 624 AM CDT THU JUL 2 2015

TRIMMED POPS IN THE NEAR TERM TO INCLUDE WHERE RADAR IS INDICATING
ACTIVITY...WHICH BOTH THE LATEST HRRR/RAP SHOW WELL. OTHER
FORECAST ELEMENTS ON TRACK. SHOULD SEE ANOTHER CHANCE OF
THUNDERSTORMS TODAY...WITH CHANCES DECREASING THROUGH THE EVENING.
THE THREAT FOR SEVERE WEATHER TODAY SHOULD REMAIN LOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)

ISSUED AT 401 AM CDT THU JUL 2 2015

THUNDERSTORM COVERAGE THIS MORNING AND ADDITIONAL THUNDERSTORM
DEVELOPMENT ON THURSDAY AFTERNOON HIGHLIGHT THE SHORT TERM
PERIOD.

SCATTERED THUNDERSTORMS WERE ONGOING OVER MUCH OF CENTRAL NORTH
DAKOTA EARLY THIS MORNING. THESE STORMS WERE RESIDING ALONG AN
AXIS OF 500 J/KG MLCAPE. WITH VERY LITTLE SHEAR IN PLACE...THE
MAIN THREATS WITH THESE STORMS WILL BE BRIEF HEAVY RAIN AND
FREQUENT LIGHTNING AS THEY DRIFT SLOWLY SOUTHEAST. SMALL HAIL AND
GUSTY WINDS WILL BE POSSIBLE WITH ANY OF THE STRONGER STORMS. AS
STORMS PUSH EAST...EXPECT PRECIP CHANCES TO DIMINISH BEHIND THEM
UNTIL LATER THIS AFTERNOON. DID KEEP PATCHY FOG IN THE FORECAST
THROUGH LATE MORNING DUE TO LOW TEMPERATURE DEW POINT SPREADS AND
A MOIST BOUNDARY LAYER...BUT DO NOT EXPECT WIDESPREAD DENSE FOG AT
THIS TIME.

THURSDAY AFTERNOON...ANOTHER SUBTLE SHORTWAVE TROUGH WILL RIDE
DOWN THE WEST COAST RIDGE FROM SASKATCHEWAN. A WEAK SURFACE TROUGH
WILL MOVE ACROSS THE COUNTY WARNING AREA FROM WEST TO
EAST...PROVIDING THE FOCUS FOR ADDITIONAL THUNDERSTORM
DEVELOPMENT. TEMPERATURES IN THE UPPER 70S AND LOWER 80S...COUPLED
WITH DEW POINTS IN THE LOW 60S...WILL YIELD MLCAPE VALUES OF
1000-1500 J/KG ACROSS CENTRAL AND EASTERN NORTH DAKOTA BY MID
AFTERNOON. HOWEVER...LACK OF SHEAR AND POOR LAPSE RATES SHOULD
SUPPRESS ANY SEVERE ACTIVITY. BY LATE EVENING...SKIES WILL BEGIN
TO CLEAR FROM WEST TO EAST AS PRECIPITATION CHANCES SLOWLY START
TO DIMINISH.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)

ISSUED AT 401 AM CDT THU JUL 2 2015

NORTHWEST FLOW ALOFT REMAINS IN PLACE FOR FRIDAY...ALTHOUGH SFC
HIGH PRESSURE RIDGE IN PLACE SO WILL MAINTAIN A DRY FRIDAY/FRIDAY
NIGHT FORECAST. NOT IMPOSSIBLE AN ISOLATED STORM COULD POP WITH
SOME ENERGY ALOFT MOVING THROUGH THE FLOW...BUT MAJORITY OF
LOCATIONS WILL REMAIN DRY SO WILL LEAVE OUT FOR NOW.

STRONG/LARGE AREA OF UPPER LEVEL LOW PRESSURE WILL MOVE SLOWLY
EAST ACROSS CANADA THIS WEEKEND INTO EARLY NEXT WEEK...AND IS THEN
FORECAST TO STALL OVER THE HUDSON BAY REGION THROUGH THE END OF
THE WORK WEEK.

AS THE UPPER LOW CROSSES THE ALBERTA ROCKIES SATURDAY...OUR FLOW
ALOFT TRANSITIONS TO MORE ZONAL WITH LOW/MID LEVEL SOUTHERLY FLOW
INCREASING AHEAD OF A STRONG FRONTAL BOUNDARY DEVELOPING AHEAD OF
THE MAIN UPPER LOW. THIS WILL PROMOTE STRONG WAA AND ATMOSPHERIC
MIXING WITH HIGHS SATURDAY WARMING BACK INTO THE LOW 80S TO LOW
90S. MAY SEE A CHANCE FOR SOME MID TO LATE AFTERNOON THUNDERSTORMS
FAR NORTHWEST NEAR THE FRONTAL ZONE...THOUGH IT APPEARS BEST
FORCING WILL BE TO OUR NORTH IN SOUTH CENTRAL CANADA.

AS THE UPPER LOW CONTINUES EAST ACROSS SASKATCHEWAN AND MANITOBA
SAT NIGHT AND SUNDAY...SFC TROUGH/STRONG COLD FRONT WILL SLOWLY
PUSH SOUTHEAST ACROSS NORTH DAKOTA. DISAGREEMENT ON TIMING WITH
THE FROPA...WITH GFS MUCH FASTER VERSUS THE EC/GEM/NAM. LEANED ON
THE MAJORITY HERE DISCOUNTING THE 00Z GFS. FRONTAL ZONE WILL BE
THE FOCUS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS...MAINLY NORTH
SATURDAY NIGHT NEAR BETTER FORCING ALOFT. ANOTHER THING TO KEEP AN
EYE ON IS THE DEVELOPMENT OF A LOW LEVEL JET (LLJ) SATURDAY
NIGHT...WHICH THE NAM SUGGESTS AND SEEMS REASONABLE CONSIDERING
THE SFC TROUGH PLACEMENT. BEST WIND SHEAR IS DISPLACED FROM BEST
MUCAPE...THOUGH COULD STILL SEE A FEW STRONGER STORMS ALONG THE
NOSE OF THE LLJ AND MUCAPE AXIS ACROSS MY
SOUTHWEST...CENTRAL...AND EASTERN COUNTIES. WENT WITH A SLIGHT CH.
POP FOR NOW FOR THESE AREAS.

FOR SUNDAY...BEST CHANCE FOR THUNDERSTORMS WILL BE ACROSS MY
SOUTHEAST IN THE AFTERNOON ONCE AGAIN NEAR THE FRONTAL BOUNDARY
AND WHEN AND WHERE MODELS SHOW THE BEST INSTABILITY AND SHEAR
COUPLED TOGETHER. ANY STRONG STORM ACTIVITY SHOULD BE SOUTH AND
EAST OF THE CWA BY EARLY SUNDAY EVENING.

SECONDARY COLD FRONT SUNDAY NIGHT INTO MONDAY WILL SEE HIGHS
MAINLY IN THE 70S FOR MONDAY. 60S NOT OUT OF THE QUESTION NORTH
NEAR THE STRONGEST CAA. SLIGHT WARMING TREND TOWARDS MID-WEEK BUT
VERY UN-JULY LIKE TEMPERATURES (HIGHS MAINLY IN THE 70S) WITH THE
UPPER LOW OVER THE HUDSON BAY PREVENTING RIDGING FROM REBUILDING
ACROSS THE ROCKIES UNTIL MAYBE LATER IN THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM CDT THU JUL 2 2015

THE TWO MAIN THREATS TODAY ARE REDUCED VISIBILITIES DUE TO SMOKE
FROM CANADIAN FIRES AND THUNDERSTORMS NEAR KBIS/KJMS. WINDS SHOULD
BEGIN TO DISSIPATE SMOKE BY 00Z SATURDAY. THUNDERSTORMS NEAR
KBIS/KJMS ARE EXPECTED TO DISSIPATE BY 02Z THIS EVENING.

&&

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

$$

UPDATE...SCHECK
SHORT TERM...ZH
LONG TERM...NH
AVIATION...SCHECK


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