Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 301434
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
934 AM CDT SAT APR 30 2016

.UPDATE...
ISSUED AT 927 AM CDT SAT APR 30 2016

QUIET WEATHER PATTERN UNDERNEATH THE NORTHERN H500 HIGH COMPONENT
OF THE REX BLOCK. SURFACE HIGH PRESSURE IN CANADA CONTINUES TO
FUNNEL VERY DRY AIR SOUTH INTO NORTHERN NORTH DAKOTA AND LOW RH
VALUES AROUND 20 PERCENT EXPECTED AGAIN TODAY NORTH. CLOUDS
SPILLING NORTH ACROSS THE SOUTH DAKOTA BORDER ASSOCIATED WITH THE
H500 DEFORMATION ZONE SO WILL INCREASE CLOUDS SOUTH. OTHERWISE
FORECAST TRENDING WELL.

UPDATE ISSUED AT 621 AM CDT SAT APR 30 2016

ADJUSTED SKY COVER THIS MORNING THROUGH EARLY AFTERNOON TO BRING
SOME INCREASING CLOUD COVER INTO THE SOUTHWEST AND SOUTH CENTRAL
AROUND 18 UTC. LATEST ITERATIONS OF THE HRRR ARE INDICATING A
CU FIELD DEVELOPING HERE MID TO LATE MORNING THROUGH EARLY
AFTERNOON. THIS IS SUPPORTED BY NAM/GFS FORECAST SOUNDINGS WITH A
SHALLOW LAYER OF MOISTURE AROUND 5K FEET. OTHERWISE NO CHANGES
OTHER THAN UPDATING LATEST OBSERVATIONS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT APR 30 2016

MARGINAL FIRE WEATHER ISSUES HIGHLIGHT THE SHORT TERM FORECAST.

OVERALL A QUIET SHORT TERM PERIOD IS IN STORE. HIGH PRESSURE OVER
THE SOUTHERN PRAIRIE PROVINCES OF CANADA AND LOW PRESSURE OVER THE
CENTRAL PLAINS IS PRODUCING A NORTHEAST TO EAST FLOW ACROSS
WESTERN AND CENTRAL THIS MORNING. THE PRESSURE GRADIENT INCREASES
THROUGH THIS MORNING BETWEEN THESE TWO FEATURES...THEN BEGINS TO
RELAX THIS AFTERNOON AS THE CENTRAL PLAINS LOW MOVES EAST.

THE STRONGEST WINDS TODAY WILL BE OVER THE SOUTHERN JAMES RIVER
VALLEY WHERE WE WILL SEE SUSTAINED WINDS AROUND 20 MPH WITH GUST
TO AROUND 30 MPH. WINDS WILL LESSEN AS YOU MOVE NORTH AND EAST BUT
WE ARE STILL EXPECTING BREEZY CONDITIONS ACROSS THE NORTH CENTRAL
TODAY WITH SUSTAINED WINDS TO AROUND 20 MPH FROM MID MORNING
THROUGH MID AFTERNOON. THIS AREA WILL ALSO SEE OUR WARMEST
TEMPERATURES AND LOWEST AFTERNOON HUMIDITIES DUE TO THE PROXIMITY
OF THE SURFACE AND UPPER LEVEL HIGH PRESSURE. WE STARTED WITH A
PERSISTENCE FORECAST FOR AFTERNOON HIGHS AND HUMIDITIES GIVEN THE
PERSISTENT SYNOPTIC PATTERN. THIS RESULTS IN AFTERNOON MINIMUM
HUMIDITIES ANYWHERE FROM 18 TO 25 PERCENT ACROSS THE NORTHWEST AND
NORTH CENTRAL. FIRE DANGER IN THE NORTH CENTRAL REMAINS IN THE
VERY HIGH CATEGORY. HOWEVER...IT LOOKS LIKE THE STRONGEST WINDS
WILL NOT CORRESPOND WITH THE LOWEST AFTERNOON HUMIDITIES GIVEN THE
EXPECTED DIMINISHING WIND SPEEDS FROM MID TO LATE AFTERNOON. WILL
PASS THIS ALONG TO THE DAY SHIFT BUT AT THIS TIME WE DO NOT
ANTICIPATE FIRE WEATHER HAZARDS. IF WINDS WOULD HOLD UP INTO THE
LATE AFTERNOON AND HUMIDITIES DROP LOWER THAN FORECAST WE COULD
SEE A PERIOD OF RED FLAG CONDITIONS. EVEN IF THIS OCCURS...THINK
IT WOULD BE HARD TO REACH THE REQUIRED TIME FRAME OF A 3 HOUR
PERIOD...SO THINK ITS MINIMAL ENOUGH THAT A FIRE WEATHER WATCH IS
NOT NEEDED.

EXPECT A GOOD AMOUNT OF SUN TODAY...ESPECIALLY NORTH. THE SYSTEM
OVER THE CENTRAL PLAINS IS SHOVING SOME MID AND HIGH LEVEL CLOUDS
INTO THE SOUTHERN COUNTIES AND THIS WILL PROBABLY CONTINUE THROUGH
MID-DAY OR SO BEFORE DIMINISHING.

MOSTLY CLEAR AND COOL TONIGHT WITH LOWS DROPPING BACK DOWN INTO
THE 30S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 231 AM CDT SAT APR 30 2016

QUIET WEATHER CONTINUES THROUGH THE LONG TERM PERIOD. UPPER LEVEL
RIDGING BUILDING OVER THE WESTERN U.S. ON SUNDAY TRANSLATES SLOWLY
EASTWARD THROUGH THE WEEK WITH AN OMEGA BLOCK PATTERN DEVELOPING
BY LATE IN THE WORK WEEK. THE ECMWF SHOWS A WAVE TRAVERSING THE
BUILDING RIDGE ON MONDAY DROPPING SOUTH THROUGH NORTH DAKOTA AND
PRODUCING A FEW SHOWERS. THIS IS FARTHER EAST THAN 24 HOURS AGO
AND IS THE WEST OUTLIER IN THE ENVELOPE OF DETERMINISTIC
SOLUTIONS. FOR NOW OUR MODEL BLEND KEEPS IT DRY ON MONDAY...AND
THIS IS THE PREFERRED SOLUTION. A STRONGER WAVE DROPPING DOWN THE
RIDGE BY MID WEEK IS FARTHER EAST BUT LOOKS TO BRING SOME SLIGHTLY
COOLER TEMPERATURES OVER CENTRAL AND EASTERN NORTH DAKOTA ON
WEDNESDAY...THEN WARMING INTO THE LATTER PORTION OF THE WORK
WEEK. THIS WAVE DEVELOPS INTO THE EAST LOW OF THE AFOREMENTIONED
OMEGA BLOCK. SIGNIFICANT MODEL DIFFERENCES ARISE AT THE END OF THE
EXTENDED PERIOD. THE ECMWF WANTS TO MERGE NORTHERN STREAM ENERGY
WITH THE WESTERN LOW AS THE NORTHERN WAVE BREAKS DOWN THE CENTRAL
U.S. RIDGE. THE GFS IS STRONGER WITH THE RIDGING OVER THE NORTHERN
PLAINS AND KEEPS THE WESTERN TROUGH SOUTH OF THE FORECAST AREA.
WITH SIGNIFICANT DETERMINISTIC MODEL DIFFERENCES AND A LARGE
SPREAD OF ENSEMBLE SOLUTIONS TO THE NORTH OF THE OMEGA
BLOCK...WILL STICK WITH OUR MODEL BLEND SOLUTION WHICH DOES BRING
PRECIPITATION CHANCES BACK INTO THE FORECAST AREA FRIDAY NIGHT AND
SATURDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 621 AM CDT SAT APR 30 2016

VFR CIGS/VSBYS THROUGH THE TAF PERIOD...ALTHOUGH A SCT/BKN CUMULUS
FIELD BASED AT 5KFT ABOVE GROUND LEVEL IS EXPECTED TO DEVELOP AT
KDIK/KBIS/KJMS THROUGH 00Z SUNDAY. NORTHEAST TO EASTERLY WINDS OF
15KT TO 25KT WILL OCCUR AT ALL TERMINALS DURING THE DAYLIGHT
HOURS TODAY.


&&

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

$$

UPDATE...WAA
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...TWH


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