Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 230543
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1243 AM CDT SAT APR 23 2016

.UPDATE...
ISSUED AT 1237 AM CDT SAT APR 23 2016

NO SIGNIFICANT CHANGES WITH THIS UPDATE...WITH THE FORECAST
BLENDED TO OBSERVED TRENDS THROUGH 05 UTC. DID MAINTAIN A SLIGHT
CHANCE MENTION OF RAIN SHOWERS LATE TONIGHT INTO EARLY SATURDAY
MORNING SOUTHWEST AND SOUTH CENTRAL AS WEAK UPPER LEVEL IMPULSES
ACROSS EASTERN MONTANA AND WYOMING PROPAGATE NORTHEAST.

UPDATE ISSUED AT 940 PM CDT FRI APR 22 2016

THERE IS A SLIGHT INCONSISTENCY BETWEEN THE SHORT TERM MODELS ON
THE TIMING FOR POPS IN THE SOUTHWEST...SO I HAVE OPTED TO LEAVE
POPS AS IS. OTHERWISE...THE CURRENT SURFACE OBSERVATIONS WERE
LOADED INTO THE FORECAST...NO CHANGES WERE MADE.

UPDATE ISSUED AT 723 PM CDT FRI APR 22 2016

SURFACE LOW PRESSURE CONTINUES TO SLIDE EASTWARD INTO NORTH DAKOTA
FROM EASTERN MONTANA. CLOUDS WILL INCREASE THROUGH THE NIGHT AND
EAST/SOUTHEASTERLY WINDS WILL REMAIN BREEZY FOR MUCH OF THE STATE.

POPS IN THE SOUTHWEST WERE ADJUSTED TO REFLECT THE LATEST TRENDS
FROM CONSSHORT...WHICH BRINGS A SLIGHT CHANCE FOR RAIN IN SLIGHTLY
LATER THAN THE PREVIOUS FORECAST.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 323 PM CDT FRI APR 22 2016

MAIN HIGHLIGHTS INCLUDE SLIGHT PRECIPITATION CHANCES SPREADING
FROM SOUTHWEST TO SOUTH CENTRAL LATE TONIGHT THROUGH SATURDAY.

LATEST SURFACE ANALYSIS MAINTAINS 3HR PRESSURE FALLS OF 1MB AND 2MB
ACROSS WESTERN AND MOST OF CENTRAL NORTH DAKOTA AS LOW LEVEL WARM
AIR ADVECTION CONTINUES. A STATIONARY FRONT IN SOUTHEAST MONTANA
WILL BEGIN TO MOVE NORTHEAST AS A WARM FRONT TONIGHT THROUGH
SATURDAY. SURFACE LOW PRESSURE IN NORTH CENTRAL MONTANA SLIDES
ALONG THE FRONT AND DEEPENS OVER THE NEXT 24HR PERIOD. INCREASING
ASCENT AND ISENTROPIC LIFT ALONG AND AHEAD OF THE WARM FRONT
TONIGHT WILL PRODUCE A SLIGHT CHANCE OF SHOWERS AFTER 06Z SOUTHWEST
NORTH DAKOTA...THEN SHIFT INTO SOUTH CENTRAL NORTH DAKOTA INCLUDING
THE JAMES RIVER VALLEY DURING THE DAYLIGHT HOURS SATURDAY. THE
WARM FRONT HUGS/MEANDER ALONG THE SOUTH/NORTH DAKOTA BORDER
SATURDAY...BEFORE BEING SHUNTED A BIT FARTHER SOUTH SATURDAY NIGHT
AS THE SURFACE LOW FROM SOUTHEAST MONTANA INTO CENTRAL SOUTH DAKOTA.

N-SHARP SOUNDINGS SHOW ADEQUATE AMOUNT OF SURFACED BASED CIN
SATURDAY RESULTING IN A SIGNIFICANT CAP IN PLACE. PLENTY OF DRY
AIR EXISTS FROM THE SURFACE  TO 700MB. AIR PARCELS ASSOCIATED
WITH ELEVATED THUNDERSTORM POTENTIAL WILL NEED TO REACH THE LEVEL
OF FREE CONVECTION WHICH AVERAGES 12KFT-14KFT. THIS WILL BE HARD
TO ACHIEVE...THUS WILL KEEP THUNDERSTORMS OUT OF THE FORECAST
THROUGH 00Z SUNDAY AT THIS TIME.

QUITE A TEMPERATURE GRADIENT FROM NORTH TO SOUTH SATURDAY WITH H85
TEMPS OF +2C IN THE FAR NORTH TO +23C IN THE FAR SOUTHWEST. IN
RESPONSE WILL BE A TIGHTENING PRESSURE GRADIENT AND INCREASING
NORTHEAST WINDS...ESPECIALLY NORTH OF INTERSTATE 94.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 PM CDT FRI APR 22 2016

THE LONG TERM PERIOD WILL REMAIN MOSTLY UNSETTLED. MAIN
HIGHLIGHTS WILL BE ELEVATED THUNDERSTORM CHANCES SUNDAY MORNING
ALONG WITH PRECIPITATION AMOUNTS OF AROUND ONE INCH TO ONE AND A
HALF INCHES SATURDAY NIGHT THROUGH MONDAY MORNING ACROSS CENTRAL
AND SOUTHERN NORTH DAKOTA.

SURFACE TO 500MB LOW CLOSES OFF AND BECOMES VERTICALLY STACKED
SATURDAY NIGHT THROUGH SUNDAY NIGHT AS IT MIGRATES ACROSS SOUTH DAKOTA.
WITH THE WARM FRONT REMAINING SOUTH OF THE BORDER...WIDESPREAD
RAIN WILL DOMINATE ACROSS ALL BUT THE FAR NORTH DURING THIS TIME.
WPC RAINFALL AMOUNTS BETWEEN 1 AND 1.5 INCHES MAINLY ALONG AND
SOUTH OF INTERSTATE 94 REMAINS ON TRACK SATURDAY NIGHT THROUGH
MONDAY MORNING.

SPC INCLUDES THE FAR SOUTHWEST IN A MARGINAL RISK FOR SEVERE
THUNDERSTORMS 12Z SATURDAY THROUGH 12Z SUNDAY. HOWEVER THE BOWMAN
N-SHARP SOUNDING SHOWS THE HIGHEST PROBABILITY FOR ELEVATED
THUNDERSTORMS COMES CLOSER TO 12Z SUNDAY WHEN THE SOUNDING MOISTENS
UP AND CIN WEAKENS SIGNIFICANTLY. PARCELS SHOULD ACHIEVE THE LEVEL
OF FREE CONVECTION MUCH EASIER WHERE ADEQUATE INSTABILITY/CAPE
EXISTS FOR THE THE PARCELS TO CONTINUE RISING. SOUNDINGS SHOW THIS
TO PEAK 12Z-15Z SUNDAY...THEN WANE BY 18Z FROM WEST TO EAST ACROSS
SOUTHERN NORTH DAKOTA.

AS COLDER 850MB AIR NOSES INTO THE PRECIPITATION COLUMN SUNDAY
EVENING/NIGHT...AND POSSIBLY CONTINUING THROUGH MONDAY PER
ECMWF...EXPECT RAIN TO MIX WITH AND CHANGE OVER TO SNOW. THIS
APPEARS MOST LIKELY IN SOUTHWEST NORTH DAKOTA SUNDAY NIGHT. HOWEVER
AS MENTIONED ABOVE THE PRECIPIATION COULD CONTINUE OVER SOUTHERN
NORTH DAKOTA THROUGH MONDAY WITH A RAIN/SNOW MIX AS WELL.

PERHAPS A BRIEF BREAK MONDAY NIGHT...THEN THE NEXT SURGE OF PRECIPITATION
DEVELOPS AGAIN TUESDAY THROUGH WEDNESDAY NIGHT. A SCENARIO SIMILAR
TO THE PREVIOUS SYSTEM FROM THE WEEKEND...BUT FARTHER SOUTH. STILL
SOME QUESTION ON PRECIPITATION AMOUNTS AND HOW WIDESPREAD THE
PRECIPITATION WILL BE. BOTH THE GFS/ECMWF SHOW A DRY DAY THURSDAY
AS THE SYSTEM DEPARTS TO THE EAST.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1237 AM CDT SAT APR 23 2016

VFR CONDITIONS ARE EXPECTED TONIGHT ACROSS WESTERN AND CENTRAL NORTH
DAKOTA. ISOLATED TO SCATTERED RAIN SHOWERS ARE POSSIBLE SOUTHWEST
AND SOUTH CENTRAL LATE TONIGHT INTO SATURDAY MORNING. CEILINGS ARE
EXPECTED TO TREND TO MVFR/IFR ACROSS MUCH OF WESTERN AND CENTRAL
NORTH DAKOTA SATURDAY EVENING AND NIGHT AS PRECIPITATION CHANCES
INCREASE ACROSS THE AREA.

&&

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

$$

UPDATE...AYD
SHORT TERM...KS
LONG TERM...KS
AVIATION...AYD



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