773
FXUS63 KBIS 161800
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1200 PM CST SAT NOV 16 2024
KEY MESSAGES
- SNOW EXPECTED ACROSS THE NORTHWEST TODAY. A MIX OF RAIN AND
SNOW ACROSS NORTH CENTRAL PORTIONS TODAY, CHANGING TO ALL SNOW
THIS EVENING.
- SNOW ACCUMULATIONS OF 1 TO 4 INCHES OF WET SNOW ARE POSSIBLE,
MAINLY IN THE NORTHWEST. BANDED SNOW POTENTIAL COULD BRING
LOCALLY HIGHER AMOUNTS.
- TEMPERATURES WILL REBOUND SUNDAY AND MONDAY TO ABOUT 10
DEGREES ABOVE AVERAGE THEN TREND COOLER THROUGH THE REMAINDER
OF THE WORKWEEK.
- ADDITIONAL RAIN AND SNOW CHANCES RETURN NEXT WEEK, THOUGH THE
BEST CHANCES ARE PRESENTLY FROM MONDAY NIGHT THROUGH WEDNESDAY
MORNING. STILL, UNCERTAINLY IN LOCATION, TIMING, AND AMOUNTS
OF ANY PRECIPITATION REMAINS HIGH.
UPDATE
ISSUED AT 1200 PM CST SAT NOV 16 2024
FORECAST OVERALL REMAINS ON TRACK. BANDED PRECIPITATION WILL
BRING PERIODS OF MODERATE SNOW TO NORTHWESTERN PORTIONS TODAY.
THIS PRECIPITATION WILL MOVE EASTWARD THIS AFTERNOON THROUGH
THIS EVENING, ALTHOUGH MAY START AS RAIN FOR CENTRAL AREAS
BEFORE SWITCHING OVER TO SNOW WITH A BRIEF WINTRY MIX DURING THE
CHANGEOVER. OVERALL LIMITED CHANGES TO PRECIPITATION NEEDED AT
THIS TIME. AHEAD OF THE PRECIPITATION ARE SOME LOW CLOUDS ALONG
WITH FOG, MIST, AND PERHAPS SOME DRIZZLE. EXTENDED PATCHY FOG
MENTION INTO THE EARLY AFTERNOON TO ACCOUNT FOR THIS, MAINLY
ACROSS CENTRAL NORTH DAKOTA.
UPDATE
ISSUED AT 1014 AM CST SAT NOV 16 2024
MAIN UPDATE IS DECISION ON ANY WINTER WEATHER PRODUCTS FOR
NORTHWESTERN PORTIONS OF THE STATE AS SNOW HAS ALREADY STARTED
TO FALL, WITH VISIBILITIES DOWN TO A HALF MILE AT TIMES. WEBCAMS
IN DIVIDE COUNTY AND UPSTREAM IN MONTANA ARE SHOWING SNOW
COVERED ROADS WITH SOME LIGHT ACCUMULATIONS ALREADY. THE MAIN
CONCERN TODAY IS FOR BANDED SNOW TO BRING LOCALLY HIGHER AND
IMPACTFUL AMOUNTS OF SNOW. FRONTOGENESIS AT 925 MB, 850 MB, AND
EVEN 700 MB LEVELS ARE FAVORABLE FOR POCKETS OF HEAVIER SNOW IN
NORTHWESTERN PORTIONS OF ND THIS MORNING THROUGH THIS AFTERNOON.
THIS AREA ALSO HAS DECENT 300 MB JET STREAM DIVERGENCE, AND
FAVORABLE LAPSE RATES. THUS THE SYNOPTIC AND MESOSCALE
ENVIRONMENT SUPPORTS BANDED SNOW. IN ADDITION, HREF 12 HOUR
SNOWFALL STAMPS ARE PLACING A WIDE RANGE OF SNOWFALL AMOUNTS IN
THE NORTHWEST TODAY, ALTHOUGH ARE SOMEWHAT CONSISTENT FOR 4 TO 6
INCHES FROM DIVIDE TO WILLIAMS TO PORTIONS OF MCKENZIE COUNTIES
AND FOR MORE ISOLATED PORTIONS OF BURKE AND MOUNTRAIL COUNTIES.
1 HOUR SNOWFALL RATES ACCORDING THE THE HREF ARE NOT QUITE TO
1 INCH PER HOUR, YET DO APPROACH 1/2 TO 3/4 INCH PER HOUR IN
SOME AREAS. GIVEN INCREASING CONFIDENCE ON ACCUMULATING SNOW AND
THE POTENTIAL FOR IMPACTFUL SNOW FROM BANDED SNOW, DECIDED TO
ISSUE A WINTER WEATHER ADVISORY TODAY INTO THIS EVENING FOR
NORTHWESTERN PORTIONS. OVERALL SNOW ACCUMULATIONS IN THESE AREAS
WILL BE 1 TO 4 INCHES, ALTHOUGH GIVEN THE BANDED SNOW POTENTIAL
4 TO 6 INCHES IS POSSIBLE.
ONLY OTHER UPDATE NEEDED THIS MORNING IS TO EXTEND THE SPS FOR
FOG IN SOUTHWESTERN AND CENTRAL PORTIONS. WEBCAMS AND
OBSERVATIONS SHOWING THIS FOG LINGERING THUS REISSUED THE SPS
UNTIL LATER THIS MORNING. WINDS SHOULD START TO INCREASE AND
BECOME WESTERLY AS THE SURFACE LOW INCREASES THE PRESSURE
GRADIENT. THIS SHOULD HELP DIMINISH THIS FOG LATER THIS MORNING
OR POSSIBLY INTO EARLY THIS AFTERNOON.
UPDATE
ISSUED AT 551 AM CST SAT NOV 16 2024
MOST RETURNS THAT WERE PRESENT A FEW HOURS AGO HAVE DISSIPATED.
HOWEVER, MORE ORGANIZED PRECIPITATION IS STARTING TO DEVELOP IN
THE FAR NORTHWEST, WITH HINTS OF ADDITIONAL NEW DEVELOPMENT IN
THE FAR WEST CENTRAL. THEREFORE, OPTED TO LEAVE POPS AS-IS FOR
NOW. PATCHY FOG HAS ALSO DEVELOPED OVER MUCH OF THE FORECAST
AREA.
DISCUSSION
ISSUED AT 333 AM CST SAT NOV 16 2024
SURFACE LOW PRESSURE IS CURRENTLY CENTERED OVER WESTERN SOUTH
DAKOTA. RADAR RETURNS ARE INCREASING OVER NORTHEASTERN MONTANA
AND NORTHWESTERN NORTH DAKOTA, ALTHOUGH BASED ON LIMITED
WEBCAMS AND OBSERVATIONS, NOT A LOT IS REACHING THE SURFACE ON
THE ND SIDE YET. MODEL FORECAST SOUNDINGS SUGGEST THE COLUMN
SHOULD SATURATE OVER THE NEXT COUPLE TO FEW HOURS. WITH
TEMPERATURES STILL NEAR 40 DEGREES, THE PRECIPITATION TYPE
SHOULD START AS RAIN. HOWEVER, AS THE LOW PROPAGATES TO THE
NORTHEAST THROUGH THE DAY TODAY, COOLER AIR IS EXPECTED TO WRAP
IN. THIS WILL RESULT IN RAIN CHANGING TO SNOW FROM WEST TO EAST.
SNOW RATIOS REMAIN PRETTY LOW THROUGH MUCH OF THE SYSTEM, THOUGH
MAY INCREASE TO AS HIGH AS 10 TO 1 LATER THIS AFTERNOON. AS A
RESULT, CURRENT EXPECTATIONS ARE FOR THE POTENTIAL OF 1 TO 3
INCHES OF WET SNOW MAINLY IN THE NORTHWEST AND FAR NORTH
CENTRAL. THE POTENTIAL EXISTS FOR LOCALIZED BANDING, HOWEVER,
WITH THE BEST CHANCE OF THIS HAPPENING IN THE FAR NORTHWEST.
SHOULD ANY BANDING OCCUR, LOCALIZED AMOUNTS UP TO 5 INCHES OF
SNOW IS NOT OUT OF THE QUESTION.
ANY LINGERING PRECIPITATION WILL END FROM WEST TO EAST TONIGHT,
WITH DRY CONDITIONS ON TAP FOR SUNDAY THROUGH SUNDAY NIGHT. BY
MONDAY, AN OMEGA BLOCKING PATTERN WILL BE IN PLACE WITH UPPER
HIGH PRESSURE CENTERED OVER FLORIDA, FLANKED BY UPPER LOWS IN
THE SOUTHWEST CONUS AND NORTH ATLANTIC OFF THE NORTHEAST COAST.
THE WESTERN LOW WILL LIFT UP THROUGH THE PLAINS STATES MONDAY
POTENTIALLY STALLING OVER THE EASTERN DAKOTAS/MINNESOTA TUESDAY
THROUGH TUESDAY NIGHT BEFORE EJECTING OFF TOWARDS THE GREAT
LAKES REGION. AS A RESULT, NBM PRECIPITATION CHANCES OF 50 TO 70
PERCENT FOR MOST OF THE CWA ARE IN THE FORECAST STARTING MONDAY
AFTERNOON MAINLY IN THE WEST, THEN EXPANDING THROUGH THE
FORECAST AREA MONDAY NIGHT, AND ENDING FROM WEST TO EAST TUESDAY
NIGHT THROUGH WEDNESDAY.
BEYOND WEDNESDAY, MOSTLY DRY CONDITIONS ARE FAVORED, ALTHOUGH
THERE ARE HINTS OF A WEAK SHORTWAVE OR TWO POTENTIALLY
PRODUCING LIGHT PRECIPITATION. OTHER THAN SNOW FOR THE FIRST
HALF OF THE WORKWEEK, ONE OF THE OTHER BIGGER STORIES FOR NEXT
WEEK IS A COOLING TREND. NBM 25TH/75TH ENSEMBLE TEMPERATURE
SPREADS REMAIN FAIRLY HIGH, BUT STILL FAVOR WIDESPREAD HIGHS
MOSTLY IN THE 30S AND LOWS IN THE TEENS STARTING TUESDAY AND
POTENTIALLY PERSISTING THROUGH THE WORKWEEK AND INTO NEXT
WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1200 PM CST SAT NOV 16 2024
A LOW PRESSURE SYSTEM WILL BRING PERIODS OF RAIN AND SNOW FROM
WEST TO EAST TODAY THROUGH THIS EVENING. BEST CHANCES FOR
PRECIPITATION WILL GENERALLY BE NORTH OF INTERSTATE 94,
IMPACTING TAF SITES KXWA AND KMOT WITH LESSER CHANCES AT KDIK
AND KBIS AND ONLY SLIGHT CHANCES AT KJMS (NOT INCLUDED IN THE
TAF AT THIS TIME). EXPECT IFR TO LIFR CONDITIONS DURING
PRECIPITATION. AHEAD OF THE PRECIPITATION MVFR TO IFR CONDITIONS
IN LOW CLOUDS, MIST, AND PATCHY FOG OR DRIZZLE CAN ALSO BE
EXPECTED. LATER THIS EVENING THROUGH TONIGHT, PRECIPITATION WILL
MOVE EASTWARD ALTHOUGH MVFR TO PERHAPS IFR CEILINGS MAY LINGER.
SOME PATCHY FOG COULD ALSO RETURN, ALTHOUGH CONFIDENCE IS NOT
HIGH ENOUGH TO INCLUDE AT THIS TIME. SUNDAY MORNING WILL THEN
SEE A TRANSITION BACK TO VFR CONDITIONS. BREEZY WESTERLY WINDS
WILL ALSO ACCOMPANY THE PASSAGE OF THIS LOW PRESSURE SYSTEM.
BIS WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 8 PM CST /7 PM MST/ THIS EVENING
FOR NDZ001-002-009-010-017.
UPDATE...ANGLIN
DISCUSSION...TELKEN
AVIATION...ANGLIN
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