Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 250525
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1225 AM CDT MON MAY 25 2015

.UPDATE...
ISSUED AT 1217 AM CDT MON MAY 25 2015

NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. LATEST RADAR
TRENDS AND IR SATELLITE INDICATE AN EXPANDING AREA OF RAIN ACROSS
SOUTHERN NORTH DAKOTA. SHORT TERM GUIDANCE SUGGESTS THIS AREA WILL
CONTINUE TO EXPAND WESTWARD EARLY THIS MORNING.
THEREFORE...UPDATED PRECIPITATION FORECAST TO REFLECT THE CURRENT
TRENDS. ALSO TOOK OUT THE MENTION OF THUNDER FOR THIS MORNING AS
VERY LITTLE IF ANY INSTABILITY EXISTS AND CURRENT SHOWER ACTIVITY
IS RATHER SHALLOW.

UPDATE ISSUED AT 940 PM CDT SUN MAY 24 2015

LATEST RADAR ANALYSIS INDICATES AN AREA OF SHOWERS ACROSS SOUTH
CENTRAL NORTH DAKOTA. THE SHOWERS CONTINUE TO TRACK TO THE WEST.
RADAR RETURNS ARE DIMINISHING CURRENTLY ACROSS THE SOUTHWEST BUT
SHOWERS IN THE SOUTH CENTRAL WILL BEGIN TO MOVE INTO THE
SOUTHWEST LATER TONIGHT. LATEST MESOSCALE RAP/HRRR INDICATE
SHOWERS SPREADING WEST FROM SOUTHEAST NORTH DAKOTA AFTER
MIDNIGHT...INTO CENTRAL NORTH DAKOTA...MAKING IT ABOUT AS FAR
NORTH AS THE HIGHWAY 200 CORRIDOR. ADJUSTED POPS BASED ON CURRENT
RADAR RETURNS AND MADE SOME MINOR ADJUSTMENTS AFTER MIDNIGHT
BASED ON MESOSCALE MODELS.

UPDATE ISSUED AT 626 PM CDT SUN MAY 24 2015

SCATTERED SHOWERS CONTINUE TO INCREASE ACROSS SOUTHERN NORTH
DAKOTA THIS EARLY EVENING. NOT EXPECT AN COMPLETE RAINOUT BY ANY
MEANS THIS EVENING BUT EXPECT THE AREAL COVERAGE TO INCREASE THIS
EVENING...BUT MORE SO AFTER MIDNIGHT. LOWERED SKY COVER OVER
NORTHWEST NORTH DAKOTA AND MADE SOME MINOR ADJUSTMENTS TO POPS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 251 PM CDT SUN MAY 24 2015

THE DEGREE OF UNCERTAINTY AND MODEL DIFFERENCES...AND YET ANOTHER
DELAY IN THE ONSET OF PRECIPITATION FOR WESTERN AND CENTRAL NORTH
DAKOTA REGARDING THE CURRENT COMPLEX STORM SYSTEM OVER THE CENTRAL
US...CONTINUES TO BE FRUSTRATING AND CHALLENGING IN THE FORECAST
PROCESS.

THE MAIN UPPER LEVEL LOW ASSOCIATED WITH THE STORM SYSTEM WAS OVER
COLORADO/WYOMING...WITH THE STRONG IMPULSES ROUNDING THE BASE OF THE
LONGWAVE TROUGH OVER THE SOUTHERN PLAINS. EVEN THOUGH SOME UPPER
LEVEL ENERGY AND MOISTURE HAS BEEN IN PLACE OVER NORTH DAKOTA THE
PAST COUPLE OF DAYS...IT HAS NOT YET BEEN ENOUGH FORCING TO ALLOW
GENERATION OF WIDESPREAD SHOWERS.

THE MODELS ARE BEGINNING TO COME TOGETHER IN BRINGING THE
COLORADO/WYOMING LOW NORTHEASTWARD INTO NE/SD/MN THROUGH MONDAY...AS
THE MAIN SHORTWAVE IMPULSE OVER THE SOUTHERN PLAINS LIFTS
NORTHEASTWARD QUICKLY INTO IOWA AND MINNESOTA BY MONDAY AFTERNOON.
THIS IS EVIDENT ON CURRENT SATELLITE AND RADAR MOSAICS WITH THE
SURGE OF PRECIP MOVING UP THE MISSISSIPPI VALLEY AND NORTHWESTWARD
OVER SOUTHERN MINNESOTA AND EASTERN SOUTH DAKOTA. THE PRECIP AROUND
THE BLACK HILLS IS ASSOCIATED WITH THE CO/WY LOW. THIS SCENARIO OF
THE SYSTEM LIFTING NORTHEASTWARD SHOULD FINALLY ALLOW ENOUGH
ENERGY/LIFT AND MOISTURE TRANSPORT TO NORTH DAKOTA FOR WIDESPREAD
SHOWERS AND EVEN SOME THUNDERSTORMS TONIGHT AND ESPECIALLY ON MONDAY.

CURRENT THINKING IS THAT SCATTERED RAIN SHOWERS WILL BECOME MORE
NUMEROUS SOUTH...AND SPREAD NORTHWARD LATER TONIGHT. MONDAY SHOULD
BE A RAINY DAY SOUTH WITH SCATTERED SHOWERS NORTH. HIGHEST RAINFALL
AMOUNTS ACROSS THE SOUTH SHOULD RANGE BETWEEN 0.50 AND 0.75 INCHES
THROUGH MONDAY AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 251 PM CDT SUN MAY 24 2015

THE LATEST WATER VAPOR SHOWS A CLOSED UPPER LOW OVER SOUTHWEST
BRITISH COLUMBIA. THIS IS THE NEXT SYSTEM TO AFFECT WESTERN AND
CENTRAL NORTH DAKOTA WITH SHOWERS AND THUNDERSTORMS BY MIDWEEK.
RIDGING APPEARS TO TAKE CONTROL FRIDAY AFTERNOON THROUGH SATURDAY.
SUNDAY IS UNCERTAIN AT THIS TIME DUE TO MODEL TIMING/PLACEMENT
DIFFERENCES OF THE NEXT SHORTWAVE.

THE GFS/ECMWF/CANADIAN GEM/NAM ARE SIMILAR/CONSISTENT WITH TAKING
THE MID/UPPER CLOSED LOW MENTIONED...AND TRACKING IT ACROSS WESTERN
AND CENTRAL NORTH DAKOTA WEDNESDAY THROUGH THURSDAY. A MID LEVEL
RIDGE IS FORECAST TO DEVELOP AHEAD OF THIS SYSTEM MONDAY NIGHT
THROUGH EARLY WEDNESDAY MORNING PROMOTING MAINLY A DRY FORECAST.
THEREAFTER THE UPPER LOW WILL MOVE ACROSS MONTANA AND NORTH DAKOTA
WITH ITS ASSOCIATED SURFACE LOW SLIDING THROUGH NORTHERN SOUTH
DAKOTA. THE INITIAL CHANCES FOR SHOWERS AND THUNDERSTORMS CAN BE
ANTICIPATED BY WEDNESDAY AFTERNOON IN THE WEST...EXPANDING INTO
CENTRAL NORTH DAKOTA WEDNESDAY NIGHT THROUGH THURSDAY. THIS IS
FOLLOWED BY A NORTHERN STREAM UPPER TROUGH THURSDAY NIGHT INTO EARLY
FRIDAY. FROM FRIDAY AFTERNOON AND INTO THE UPCOMING WEEKEND...BROAD
RIDGING TAKES CONTROL WITH DRIER CONDITIONS. BOTH THE ECMWF AND GFS
SHOW A PROGRESSIVE PATTERN WITH ANOTHER SHORTWAVE SLIDING ACROSS
SUNDAY. THE ECMWF REACHES FARTHER SOUTH INTO NORTH DAKOTA WITH THIS
SHORTWAVE AND ASSOCIATED PRECIPITATION...WHILE THE GFS KEEPS IT ALL
NORTH OF THE BORDER.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1217 AM CDT MON MAY 25 2015

MVFR CONDITIONS ARE EXPECTED AT KDIK/KBIS/KJMS WITH VFR AT KISN
AND KMOT. RAIN WILL CONTINUE TO EXPAND OVER THE SOUTHERN TERMINALS
THIS MORNING. THERE IS SOME UNCERTAINTY WITH RESPECT TO INTENSITY
AND CIG HEIGHT. MODERATE RAIN WAS FALLING JUST SOUTH OF THE ND
BORDER THIS MORNING AND SOME IFR CIGS WERE NOTED...HOWEVER RAIN
ACROSS ND WAS LIGHTER AND CIGS WERE CONSIDERABLY HIGHER.
THEREFORE...ONLY KEPT MVFR CIGS AT THE SOUTHERN TERMINALS TODAY.

&&

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

$$

UPDATE...AJ
SHORT TERM...JV
LONG TERM...KS
AVIATION...AJ


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