892
FXUS63 KBIS 202101
AFDBIS
FXUS63 KBIS 202101
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
401 PM CDT SAT MAR 20 2010
SYNOPSIS
HIGH PRESSURE OVER THE CENTRAL PLAINS WILL BRING A DRY
SOUTHWEST FLOW TO WESTERN AND CENTRAL NORTH DAKOTA.
SHORT TERM
CURRENTLY...UPPER LEVEL TROUGH STRETCHES FROM THE GREAT LAKES TO TO
TEXAS...RESULTING IN NORTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS.
A LARGE DOME OF SURFACE HIGH PRESSURE RESIDES OVER THE CENTRAL
PLAINS...AND WITH A LOW PRESSURE AREA/COLD FRONT TO THE NORTH...THE
PRESSURE GRADIENT OVER THE FORECAST AREA HAS PRODUCED A STEADY
SOUTHWESTERLY WIND ACROSS THE ENTIRE FORECAST AREA. THE DOWNSLOPING
COMPONENT TO THE WIND HAS HELPED TO BRING TEMPERATURES UP TO THE
UPPER 30S AND LOWER 40S THIS AFTERNOON.
MODELS ARE IN GOOD AGREEMENT DURING THE TERM...SO HAVE CONTINUED
WITH A GENERAL BLEND FOR THE FORECAST. MAIN FORECAST CONCERNS WILL
BE WARM TEMPERATURES UP UNTIL MONDAY...THEN THE CHANCE FOR PRECIP AS
A CLIPPER TYPE SYSTEM SWEEPS ACROSS THE STATE.
TONIGHT AND SUNDAY...UPPER LEVEL RIDGING ATTEMPTS TO NUDGE INTO THE
AREA FROM THE SOUTHWEST...SHIFTING UPPER LEVEL FLOW FROM
NORTHWESTERLY TO NEAR-ZONAL. THE COLD FRONT TO THE NORTH IS EXPECTED
TO STALL OUT ALONG THE INTERNATIONAL BORDER AS IT IS CUT OFF FROM
ITS PARENT SYSTEM IN CENTRAL AND EASTERN CANADA. THEREFORE...WARM
TEMPERATURES AND CLEAR SKIES SHOULD REMAIN IN PLACE WITHIN THE
FORECAST AREA. SOUTHWESTERLY WINDS ARE EXPECTED TO SHIFT MORE TO THE
SOUTH BY TUESDAY MORNING...AND THE RESULTANT WARM AIR ADVECTION
SHOULD BRING TUESDAY'S HIGH TEMPS UP ANOTHER 5 TO 10 DEGREES.
MEANWHILE...A LEE-SIDE LOW IS FORECAST TO DEVELOP IN SOUTHERN
ALBERTA...AS AN UPPER LEVEL TROUGH BEGINS TO MOVE ONSHORE IN THE
PACIFIC NORTHWEST. BY MONDAY...THE TROUGH LENDS ITS SUPPORT TO THE
LOW AND THE SYSTEM BEGINS TO TRACK TO THE SOUTHEAST INTO MONTANA AND
NORTH DAKOTA. BY MONDAY AFTERNOON...THE CENTER OF THE LOW SHOULD
MOVE INTO WESTERN SD BEFORE CONTINUING SOUTH INTO THE CENTRAL PLAINS
TUESDAY. COLD FRONTAL PASSAGE IS EXPECTED SOMETIME OVERNIGHT
MONDAY...AND WILL LIKELY BRING A ROUND OF COLDER TEMPS FOR TUESDAY.
MODELS INDICATE THAT THERE MAY BE TWO ROUNDS OF PRECIPITATION
EXPECTED WITH THIS CLIPPER. THE FIRST ROUND IMPACTS THE NORTHERN
HALF OF THE STATE MONDAY AFTERNOON...AND IS ASSOCIATED WITH THE
INCREASED LIFT ALONG THE NEARLY STATIONARY FRONTAL BOUNDARY LEFT IN
PLACE FROM SUNDAY. WITH THE WARM AIR IN PLACE...MOST OF THIS PRECIP
SHOULD FALL AS RAIN...WITH AMOUNTS OF A QUARTER INCH OR LESS
EXPECTED AS A RESULT. THE SECOND ROUND IS ASSOCIATED MORE WITH THE
UPPER LEVEL SYSTEM THAT TRAVERSES THE AREA TUESDAY...AND WILL OCCUR
WITH MUCH COOLER TEMPS IN PLACE BEHIND THE SURFACE LOW. WILL
THEREFORE KEEP A CHANCE OF LIGHT SNOW AND RAIN IN THE FORECAST
THROUGH TUESDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY
THE GFS AND ECMWF FORECAST MODELS REMAIN IN PRETTY DECENT AGREEMENT
IN REGARDS TO THE OVERALL LARGE SCALE PATTERN FOR THE EXTENDED
PERIOD.
THE REGION WILL BE UNDER THE INFLUENCE OF NORTHWESTERLY FLOW ALOFT
WED-WED NIGHT AS SPLIT FLOW ALOFT DEVELOPS KEEPING PRECIPITATION
CHANCES NORTH AND SOUTH OF THE LOCAL AREA. THE NORTHERN STREAM
TROUGH WILL PUSH A BACK DOOR COLD FRONT INTO THE NORTHEASTERN HALF
OF THE STATE LATER WED...BRINGING COLDER MID LEVEL TEMPERATURES TO
CENTRAL AND EASTERN PORTIONS OF THE CWA FOR THURS. MY SOUTHWEST
LOOKS TO BE SPARED AS THE COLD FRONT STALLS OVER CENTRAL ND.
RESULTANT TEMPERATURES WILL RANGE FROM THE LOW 40S NORTHEAST TO LOW
50S SOUTHWEST ON WED...THEN FROM THE LOW 30S NORTHEAST TO NEAR 50
FAR SOUTHWEST THURS. ANOTHER WEAK COLD FRONT IS STILL DEPICTED TO
DROP SOUTH THROUGH THE REGION THURS NIGHT-FRI NIGHT...BRINGING
ANOTHER CHANCE FOR LIGHT PRECIPITATION ALONG WITH ANOTHER SURGE OF
COOLER TEMPERATURES MAINTAINING HIGHS SLIGHTLY BELOW NORMAL VALUES.
NIGHTTIME/MORNING LOWS LOOK TO REMAIN SUBFREEZING THROUGH THE
PERIOD.
CURRENT LONG RANGE GUIDANCE INDICATES A MUCH STRONGER MODERATION IN
TEMPERATURES BEGINNING LATE NEXT WEEKEND AND CONTINUING INTO THE
FOLLOWING WORK WEEK AS A BROAD UPPER RIDGE BUILDS INTO THE NORTHERN
PLAINS.
AVIATION
LARGE HIGH PRESSURE DOME ACROSS THE CENTRAL US WILL CONTINUE TO
RESULT IN VFR CONDITIONS FOR ALL TAF SITES IN THE REGION. EXPECT
CONTINUED HIGH CLOUDS ACROSS THE STATE...WITH SOUTHWESTERLY WINDS
DECREASING SOME AROUND AND AFTER SUNSET.
HYDROLOGY
COLDER TEMPERATURES TODAY HAVE DECREASED OVERLAND FLOODING SOUTH
CENTRAL HOWEVER AT THE SAME TIME INCREASED THE ICE JAM FLOODING IN
THE WEST.
POINT FORECAST FOR RIVER FLOODING CONTINUING FOR LAMOURE ON THE
JAMES...LUDDEN DAM ON THE JAMES AND NEAR PINGREE ON THE PIPESTEM
CREEK.
PIPESTEM CREEK IS FORECAST TO RISE ANOTHER HALF FOOT TO NEAR 9.9 ON
3/26. ON THE JAMES LA MOURE IS FORECAST TO RISE TO 16.2 FEET FROM
ITS CURRENT LEVEL OF 15.4 AND LUDDEN IS FORECAST TO CONTINUE A SLOW
RISE TO 16.6 FEET ON 3/28.
IN THE SOUTH CENTRAL COLDER TEMPERATURES HAVE REDUCED OVERLAND
FLOODING BUT BEAVER CREEK AT LINTON AND APPLE CREEK NEAR MENOKEN
REMAIN ABOVE FLOODS STAGE. BEAVER CREEK IS FORECAST TO CREST AT
14.0 FEET ON 3/24 AND APPLE CREEK IS FORECAST TO CREST AT 15.1 FEET
ON 3/25
BIS WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR NDZ017-031-032-040-043.
SHORT TERM/HYDROLOGY...HW
LONG TERM...NH
AVIATION...BPN
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