Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 291431
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
931 AM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 931 AM CDT MON JUN 29 2015

CURRENT FORECAST ON TRACK.

MAIN ISSUE FOR THE DAY IS THE SMOKE ALOFT FROM THE ALBERTA AND
SASKATCHEWAN FIRES POSSIBLY LIMITING INSOLATION AND...IN TURN...HIGH
TEMPS FOR TODAY. CURRENT WATER VAPOR LOOP APPEARS TO INDICATE THAT
THE SMOKE ALOFT IS IMPACTING THE EASTERN HALF OF NORTH DAKOTA...WITH
MAINLY SMOKE-FREE CONDITIONS WEST HALF. FORECAST MODELS INDICATE THE
UPPER LEVEL NORTHERLY JET CONTINUING TO MOVE EAST TODAY AS THE
WESTERN RIDGE BUILDS OVER THE ROCKIES INTO THE WESTERN PLAINS. THUS
THE CURRENT FORECAST FOR HIGHS IN THE LOWER 90S WEST AND UPPER 80S
TO AROUND 90 CENTRAL IS ON TRACK.

UPDATE ISSUED AT 650 AM CDT MON JUN 29 2015

INHERITED FORECAST IS ON TARGET WITH NO CHANGES WARRANTED.

A FEW SPRINKLES WERE IN THE SIDNEY...MONTANA AREA...AND IN
SOUTHEAST SASKATCHEWAN NORTHWEST OF MINOT. MOVEMENT WAS SOUTHEAST
WITH RADAR SHOWING FEWER RETURNS THAN EARLIER.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON JUN 29 2015

THE LATEST WATER VAPOR IMAGERY LOOP SHOWS A HIGHLY AMPLIFIED RIDGE
CENTERED OVER NORTHERN ARIZONA WITH THE RIDGE AXIS EXTENDING NORTH
ALONG THE BRITISH COLUMBIA/ALBERTA BORDER. NORTH DAKOTA REMAINS IN
A NORTHWEST FLOW ALOFT AND THIS WILL CONTINUE THROUGH THE SHORT
TERM PERIOD. EARLY THIS MORNING...A SHORTWAVE IN EASTERN MONTANA
WITH AN ASSOCIATED 300MB 70KT JET STREAK THUS FAR HAS GENERATED
AN ISOLATED THUNDERSTORM IN SOUTHEAST SASKATCHEWAN...JUST NORTH OF
DIVIDE COUNTY. HIGH RESOLUTION MODELS ARE WAY OVERDONE WITH THE
COVERAGE OF PRECIPITATION EARLY THIS MORNING. AT THE SURFACE...MOSTLY
CLEAR CONDITIONS CONTINUE WITH HAZE ACROSS CENTRAL NORTH DAKOTA.
JAMESTOWN AIRPORT FLUCTUATING BETWEEN 6SM AND 7SM...WITH SIMILAR
CONDITIONS AT BISMARCK. ONE OF THE FORECAST CONCERNS TODAY IS THE
AMOUNT OF SMOKE/HAZE EMBEDDED WITHIN THE NORTHWEST FLOW FROM THE
CANADIAN WILDFIRES IN ALBERTA AND SASKATCHEWAN. JUST LIKE
SUNDAY...THE SKY AND SUBSEQUENT TEMPERATURE GRIDS WILL BE
DEPENDENT UPON THE AMOUNT OF OBSCURATION ALOFT. NOT REAL CONFIDENT
ON THE TIMING EXTENT OF BLOCKED INSOLATION THAT MAY OR MAY NOT
OCCUR. HAVE MENTIONED HAZE IN THE GRIDS AT LEAST THROUGH 18Z AND
THIS MAY NEED TO BE EXTENDED. SHALLOW INVERSIONS BREAKING BETWEEN
14Z AND 15Z WILL ALLOW LOWER VISIBILITIES TO LIFT AND IMPROVE
THEREAFTER.

THE OTHER CONCERN IS THIS AFTERNOON MAINLY OVER EAST CENTRAL
NORTH DAKOTA. WEAK 3HR PRESSURE FALLS WERE OCCURRING OVER
SOUTHEAST MANITOBA EARLY THIS MORNING...AHEAD OF A BACKDOOR COLD
FRONT MOVING SOUTH. A HANDFUL OF LIGHTNING STRIKES WERE OBSERVED
WITHIN THE PRESSURE FALL AREA. AN 80KT-90KT JET STREAK IN SOUTHEAST
SASKATCHEWAN WILL MOVE EAST INTO MANITOBA AND CENTRAL/EASTERN
NORTH DAKOTA THROUGH 00Z TUESDAY. SOME INTERACTION BETWEEN A
SHORTWAVE...THE LEFT EXIT REGION OF THE JET...AND THE SURFACE BACK
DOOR COLD FRONT MAY TRIGGER A SHOWER/THUNDERSTORM IN THE JAMES
RIVER VALLEY LATE IN THE AFTERNOON. UNCERTAINTY ON THE TIMING OF
INTERACTION MENTIONED ABOVE. BEST FORCING REMAINS IN EASTERN NORTH
DAKOTA AND MINNESOTA. FOR NOW HAVE DECIDED TO KEEP THE FORECAST
DRY...ESPECIALLY WITH THE HIGH RESOLUTION ARW/NMM NOT RELIABLE
THIS MORNING...AND THE RAP13 ALONG WITH THE MAJORITY OF THE GLOBAL
SUITE KEEPING THINGS DRY. TRYING TO COVER THE UNCERTAINTY WITH A
SLIGHT CHC OVER A LARGE AREA IS NOT PRUDENT AT THIS TIME. WILL
LET THE DAY SHIFT LOOK AT THE CURRENT DATA AND ADJUST IF NEED BE.

FOR MONDAY NIGHT...POPS INCREASE NORTHWEST AFTER 06Z AND THEN
EXPAND SOUTH THROUGH 12Z TUESDAY. A SHORTWAVE TROUGH CURRENTLY OFF
THE WASHINGTON/OREGON COAST PER WATER VAPOR IMAGERY... RIDES OVER
AND FLATTENS THE AFOREMENTIONED RIDGE...SPAWNING AN AREA OF
SURFACE LOW PRESSURE FROM MONTANA INTO WESTERN SOUTH DAKOTA. LOW
LEVEL MOISTURE INCREASES IN RESPONSE TO SOUTHEAST WINDS INCREASING
OVERNIGHT ESPECIALLY WEST. A SLIGHT CHANCE FOR THUNDERSTORMS WILL
SUFFICE FOR NOW...WITH HIGHER POPS FOLLOWING THE SHORT TERM PERIOD.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON JUN 29 2015

THE PROTECTIVE RIDGE OF THE LAST FEW DAYS BEGINS TO BREAK DOWN AT
THE START OF THE LONG TERM WITH A CHANGE TO COOLER AND STORMY
WEATHER FOR TUESDAY THROUGH THURSDAY. A SERIES OF SHORT WAVES SPIN
OFF THE LOW OFF OF BRITISH COLUMBIA AND WORK TO FLATTEN THE RIDGE
AS THEY PASS THROUGH THE NORTHERN PERIPHERY. THE FIRST OF THESE
COMES IN FOR TUESDAY AND WITH INCREASING MOISTURE AHEAD OF A
SURFACE FRONT COMES INCREASING INSTABILITY...ALBEIT IN A NARROW
BAND AS SHOWN ON MODELS...UP ALONG THE NORTH DAKOTA AND MONTANA
BORDER. AS FAR AS SEVERE STORMS GO...SPC HAS INCLUDED WESTERN
NORTH DAKOTA IN THE MARGINAL RISK AREA.

ANOTHER WAVE IS SCHEDULED FOR EARLY WEDNESDAY. THIS ONE IS WEAKER
AND THE TIMING WOULD BE AT A RELATIVE MINIMUM FOR SEVERE WEATHER
RISK. THE THIRD AND FINAL ONE BEFORE THE RIDGE RE-AMPLIFIES IS SET
FOR MID DAY THURSDAY. POPS CONTINUE RELATIVELY HIGH REFLECTING
MODEL CONSISTENCY AND AGREEMENT.

THE FOURTH OF JULY WEEKEND LOOKS DRY MOST OF THE TIME...WITH A
WAVE SATURDAY NIGHT HIGHLIGHTING THE MOST LIKELY TIME PERIOD FOR
STORMS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 650 AM CDT MON JUN 29 2015

SMOKE FROM THE CENTRAL CANADIAN WILDFIRES WILL CONTINUE TO TRAVEL
INTO NORTH DAKOTA. VSBYS FORECAST TO REMAIN AT OR ABOVE 6SM. AS
SHALLOW SURFACE INVERSIONS BREAK BY MID TO LATE MORNING EXPECT
IMPROVED VISIBILITIES. A WEAK COLD FRONT WILL SLIDE FROM NORTH TO
SOUTH ACROSS CENTRAL NORTH DAKOTA MONDAY AFTERNOON WITH NORTHWEST
WINDS OF 15 TO 25 KNOTS AT KJMS AFTER 16Z. OTHERWISE A VERY LOW
PROBABILITY EXISTS FOR A SHOWER OR THUNDERSTORM NEAR KJMS THIS
AFTERNOON...BUT TOO REMOTE FOR NOW FOR ANY MENTION IN THE TAF.
VFR CIGS AND VSBYS AT ALL TERMINALS THROUGH 12Z TUESDAY.


&&

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

$$

UPDATE...JV
SHORT TERM...KS
LONG TERM...JPM
AVIATION...KS/JPM


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