000
FXUS63 KBIS 171905
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
205 PM CDT THU APR 17 2014

.UPDATE...
ISSUED AT 1252 PM CDT THU APR 17 2014

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD INCLUDE INCREASING
PRECIPITATION CHANCES ACROSS THE WEST...ESPECIALLY FRIDAY AFTERNOON.

IN THE NEAR TERM...SNOW SHOWERS IN THE FAR SOUTHWEST HAVE
DISSIPATED WHILE CLOUDS CONTINUE TO INCREASE FROM WEST TO EAST
ACROSS THE FORECAST AREA. THE HIGH PRESSURE RIDGE HAS MOVED INTO
THE RED RIVER VALLEY WITH AN INCREASING PRESSURE GRADIENT AND
BRISK SE FLOW ACROSS THE WEST. HIGH RESOLUTION MODELS...INCLUDING
THE RAP AND HRRR..INDICATING A 500MB SHEARED VORTICITY AXIS
PUSHING INTO WESTERN NORTH DAKOTA THIS EVENING AND PUSHING EAST
OVERNIGHT. A SWATH OF ENHANCED LIFT MAY SUPPORT SOME LIGHT
RAIN/SNOW SHOWERS FROM NORTHWEST TO SOUTHEAST TONIGHT AND HAVE
MADE SOME MINOR ADJUSTMENTS TO POPS.

ON FRIDAY...EXPECT BREEZY CONDITIONS BUT WIDESPREAD ADVISORY
CRITERIA (SUSTAINED 30 MPH) IS NOT EXPECTED TO BE REACHED.
INCREASING WARM AIR ADVECTION WILL BOOST AFTERNOON TEMPERATURES
INTO THE 50S TO LOWER 60S. AN UPPER LEVEL LOW WILL PUSH INTO
MONTANA WITH DIFFLUENT SOUTHWEST FLOW SUPPORTING RAIN ACROSS
NORTHWEST NORTH DAKOTA...ESPECIALLY DURING THE AFTERNOON HOURS.

UPDATE ISSUED AT 951 AM CDT THU APR 17 2014

MORNING UPDATE FOR MINOR CHANGES TO POPS ACROSS THE WEST AND
HOURLY TEMPERATURE TRENDS. LIGHT SNOW SHOWERS CONTINUE ACROSS THE
FAR SOUTHWEST THIS MORNING. EXPECTING TRANSITION TO LIGHT RAIN
THIS AFTERNOON...WITH ANY PRECIPITATION CONFINED MAINLY TO THE
WESTERN THIRD OF THE FORECAST AREA.

UPDATE ISSUED AT 700 AM CDT THU APR 17 2014

BOWMAN RADAR WAS SHOWING WEAK RETURNS THROUGH SOUTHWEST NORTH
DAKOTA. FLURRIES THIS MORNING...ISOLATED RAIN SHOWERS LATER AS WE
WARM...WESTERN THIRD.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT THU APR 17 2014

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD INCLUDE TEMPERATURES
AND POSSIBLY SOME LIGHT SHOWERS IN THE WEST.

CURRENTLY...HIGH PRESSURE WAS CENTERED OVER SOUTHERN MANITOBA WITH
LOW PRESSURE IN THE LEE OF THE ROCKIES. PERSISTENT CLOUDS LINGERED
BETWEEN THE HIGH PRESSURE RIDGE AXIS THAT EXTENDED SOUTHWARD FROM
MANITOBA ACROSS THE CENTRAL DAKOTAS...AND THE LEE-SIDE LOW PRESSURE
TROUGH. REGIONAL RADARS INDICATED THAT LIGHT SHOWERS OR VIRGA
CONTINUED OVER EASTERN MONTANA INTO WESTERN SOUTH DAKOTA AND THE
SOUTHWESTERN CORNER OF NORTH DAKOTA.

THE AREA OF LIGHT SHOWERS IS LIKELY ASSOCIATED WITH AN UPPER LEVEL
IMPULSE MOVING EAST/SOUTHEAST IN THE NORTHWEST FLOW ALOFT. THIS
IMPULSE IS FORECAST TO MOVE ACROSS WESTERN NORTH DAKOTA THIS
MORNING...THEN WEAKEN FURTHER AS IT MOVES INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. MEANWHILE AT THE SURFACE...THE SURFACE GRADIENT
TIGHTENS TODAY AND SHOULD BE CONDUCIVE FOR GUSTY SOUTHEAST WINDS
OVER WESTERN NORTH DAKOTA LATE THIS MORNING AND INTO THE AFTERNOON.
H850 WINDS AROUND 25 MPH FROM THE SOUTHEAST...WITH GOOD WARM
ADVECTION AT H700 WITH WESTERLY WINDS. THIS SCENARIO WILL KEEP WARM
ADVECTION CLOUDS DEVELOPING OVER THE WESTERN HALF OF THE STATE. THIS
COMBINED WITH WEAK UPPER LEVEL ENERGY IMPULSES WILL KEEP A CHANCE OF
SHOWERS OVER WESTERN NORTH DAKOTA TODAY.

TONIGHT A SHORTWAVE RIDGE WILL MOVE INTO WESTERN NORTH DAKOTA AHEAD
OF A MORE SIGNIFICANT TROUGH. THE LEADING EDGE OF UPPER LEVEL ENERGY
WITH THIS NEXT UPPER TROUGH WILL APPROACH NORTHWESTERN NORTH DAKOTA
LATE TONIGHT. THE BEST THUS WILL KEEP A MENTION OF SHOWERS AFTER
MIDNIGHT IN THE NORTHWEST AND NORTH CENTRAL.

THE SLOW WARMING TREND BEGINS WITH HIGHS TODAY IN THE 40S...WITH
LOWER 50S IN THE FAR SOUTHWEST.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 430 AM CDT THU APR 17 2014

THIS LONG TERM DISCUSSION VERY SIMILAR TO THAT FROM YESTERDAY AND
EXPECTATIONS HAVE CHANGED ONLY SLIGHTLY FOR THE LONG TERM.

OF MOST INTEREST CONTINUES TO BE THE SIGNIFICANT WARM UP JUST IN
TIME FOR EASTER...WITH HIGHS 65 TO 70 FOR MOST OF THE FORECAST
AREA THAT DAY. THE THUNDERSTORM CHANCES REMAIN...ESPECIALLY SOUTH...
FROM LATER TUESDAY THROUGH WEDNESDAY...BUT INSTABILITY PARAMETERS
ARE WEAKER THAN PREVIOUSLY INDICATED.

THE LONG TERM IS VERY ACTIVE WITH A MID LEVEL COLD POCKET PASSING
JUST NORTH OF THE FORECAST AREA TO START...FOLLOWED BY
SIGNIFICANT RIDGING IN THE MID LEVELS BEGINNING SATURDAY AFTERNOON
AND CONTINUING INTO MID WEEK. THE COLD POCKET BRINGS MIXED
PRECIPITATION...PREDOMINANTLY RAIN DURING THE DAY TIMES AND SNOW
AT NIGHT. SNOW ACCUMULATIONS WILL BE MINIMAL WITH MAYBE AN INCH...
AT MOST...WEST AND NORTH. THIS WOULD BE QUICK TO MELT DURING DAY
TIMES AND WITH RAIN.

THE PERIOD IMMEDIATELY AFTER THE LONG TERM...SO THURSDAY AND
FRIDAY...LOOKS WET AT FIRST AND THEN WITH COLDER AIR WORKING IN AS
THE SYSTEM PULLS OUT...A CHANCE THAT PRECIPITATION WOULD END AS A
PERIOD OF SNOW...THAT FOR APRIL 24-25...AND FOR MOST WOULD BE
UNWELCOME.

TO BACK UP A BIT CONCERNING THE THUNDERSTORM CHANCES FOR TUESDAY
AND WEDNESDAY...LOW PRESSURE FORMS IN THE LEE OF THE ROCKIES. THE
THERMAL RIDGE AHEAD OF IT...INTO NORTH DAKOTA...IS NOW DEPICTED BY
THE MODELS NOT AS STRONG AS YESTERDAYS RUNS. THE LOW IS ALSO
DEPICTED WEAKER AND WITH THAT THE INCREASE IN LOW LEVEL MOISTURE
AND INSTABILITY LESS. CAPE THAT WAS FORECAST TO NEAR 1500 J/KG
ALONG THE SOUTH DAKOTA BORDER AND LI TO -4...IS NOW DEPICTED AS
LESS THAN 500 J/KG AND LI TO -2. IT IS STILL PRUDENT TO KEEP A
MENTION OF THUNDERSTORMS...BUT THEY COULD BE MORE THUNDERSHOWERS
AS COMPARED TO STORMS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1252 PM CDT THU APR 17 2014

EXPECTING MAINLY LOW VFR CEILINGS BECOMING MVFR THIS EVENING AT
KMOT/KISN/KBIS. ISOLATED LIGHT SNOW SHOWERS WILL BE POSSIBLE
OVERNIGHT AT KISN/KMOT...BUT LOW PROBABILITY DOES NOT WARRANT MORE
THAN A VCSH MENTION AT THIS TIME.

&&

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

$$

UPDATE/AVIATION...RP KINNEY
SHORT TERM...JV
LONG TERM...JPM