118
FXUS63 KBIS 220859
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
259 AM CST SUN DEC 22 2024
KEY MESSAGES
- AREAS OF FOG POSSIBLE TONIGHT INTO SUNDAY MORNING.
- FREEZING RAIN EXPECTED ACROSS NORTHWESTERN NORTH DAKOTA ON
SUNDAY, WITH A WINTRY MIX OF RAIN, FREEZING RAIN, AND SNOW
POSSIBLE ELSEWHERE.
- A WARMING TREND IS EXPECTED THIS WEEKEND THROUGH EARLY NEXT
WEEK ACROSS WESTERN NORTH DAKOTA, WITH ABOVE NORMAL
TEMPERATURES FAVORED STATEWIDE FROM CHRISTMAS EVE THROUGH THE
END OF THE WEEK.
UPDATE
ISSUED AT 258 AM CST SUN DEC 22 2024
QUICK UPDATE FOR THE ISSUANCE OF A DENSE FOG ADVISORY FOR MUCH
OF NORTHWEST AND NORTH CENTRAL NORTH DAKOTA. THE WINTER WEATHER
ADVISORY HAS ALSO BEEN EXPANDED INTO CENTRAL NORTH DAKOTA, WHICH
WILL BE ADDRESSED IN THE COMING FULL PACKAGE DISCUSSION.
UPDATE
ISSUED AT 957 PM CST SAT DEC 21 2024
MADE A FEW CHANGES WITH THE LATE EVENING UPDATE. ADJUSTED POPS
BASED ON A BLEND OF SHORT RANGE MODELS. THE MAIN OBJECTIVE HERE
WAS TO DELAY THE TIMING BY COUPLE HOURS, AND LIMIT THE EASTERN
EXTENT OF THE LOWER PRECIPITATION CHANCES. WILL KEEP THE TIMING
OF THE ADVISORY THE SAME FOR NOW BUT WILL PASS ALONG THE DELAY
TO THE OVERNIGHT SHIFT. IT'S POSSIBLE THE ONSET COULD BE PUSHED
BACK A BIT, BUT STILL WAITING ON SOME 00Z GUIDANCE TO ARRIVE.
WE ALSO LIMITED THE EXTENT OF FOG THROUGH THIS EVENING AND INTO
THE EARLY OVERNIGHT HOURS. CAMS STILL HAVE FOG INCREASING IN THE
NORTH AND SPREADING SOUTH, BUT IS DELAYED A BIT. UPDATED TEXT
PRODUCTS WILL BE TRANSMITTED SHORTLY.
UPDATE
ISSUED AT 546 PM CST SAT DEC 21 2024
MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL ND EARLY THIS
EVENING. THE EXCEPTION BEING LOW STRATUS AND FOG REMAINING
AROUND THE TURTLE MOUNTAINS IN BOTTINEAU AND ROLETTE COUNTIES.
WITH SOME REDUCED VISIBILITIES REPORTED EARLY THIS EVENING AT
BOTTINEAU AND ROLLA, ADDED A MENTION OF PATCHY FOG. OTHERWISE NO
CHANGES NEED ED TO THE GOING FORECAST.
DISCUSSION
ISSUED AT 332 PM CST SAT DEC 21 2024
WESTERLY FLOW PATTERN ALOFT WILL CONTINUE THROUGH TONIGHT, WHILE
A SURFACE HIGH PRESSURE TO OUR NORTH MAINTAINS LIGHT WINDS
ACROSS THE REGION. OVERALL LOOK FOR MAINLY DRY CONDITIONS
THROUGH TONIGHT, WITH LOWS IN THE SINGLE DIGITS TO THE NORTH AND
WARMING INTO THE 20S ACROSS THE SOUTHWEST. SOME LINGERING CLOUD
COVER WILL ALSO BE FOUND IN THE NORTH AND EAST THROUGH THIS
EVENING, WITH INCREASING CLOUDS FROM AN APPROACHING CLIPPER
SYSTEM FOUND LATER TONIGHT. BEFORE THIS SYSTEM ARRIVES, LIGHT
WINDS AND INCREASED TEMPERATURES WILL BRING THE POTENTIAL FOR
PATCHY TO AREAS OF FOG TO MUCH OF THE CWA TONIGHT. HI-RES MODELS
INDICATE THERE COULD BE SOME DENSE FOG AT TIMES TONIGHT PERHAPS
LINGERING INTO SUNDAY MORNING.
CLIPPER SYSTEM THEN MOVES ACROSS THE STATE SUNDAY MORNING
THROUGH THE DAY, EXITING SUNDAY EVENING. ENSEMBLES AND
DETERMINISTIC FORECAST DATA CONSISTENT ON THIS WAVE TAKING MORE
OF SOUTHWESTERN ND TRACK, ALTHOUGH MODELS INDICATING SOME DECENT
QG CONVERGENCE ALONG AND NORTH OF THE MISSOURI RIVER. THERE IS
LIMITED FRONTOGENESIS FORECAST WITH THIS WAVE, THUS LIMITING THE
BANDING POTENTIAL. THE MAIN CONCERN WITH THIS WAVE WILL BE THE
FREEZING RAIN POTENTIAL GIVEN THE WARM AIR ALOFT ALREADY IN
PLACE DURING PASSAGE OF THIS WAVE. FORECAST SOUNDINGS SHOWING
ANYTHING FROM BRIEF FREEZING FOLLOWED BY SNOW, TO FREEZING
DRIZZLE OR FREEZING RAIN, TO DRY AIR LIMITING FREEZING RAIN
UNTIL SATURATION WHEN MAINLY SNOW WOULD TAKE OVER. THUS A WIDE
RANGE OF UNCERTAINTY REMAINS WITH THIS SYSTEM WHEN IT COMES TO
PTYPES. THERE IS SOME INCREASING CONFIDENCE THOUGH FOR FREEZING
RAIN INITIALLY IN THE NORTHWEST STARTING SUNDAY MORNING. 70% OF
THE CLUSTERS SHOWING LIGHT ICE ACCUMULATION IN THESE AREAS.
GIVEN THIS SLIGHTLY INCREASED CONFIDENCE AND THE POTENTIAL
IMPACTS TO HOLIDAY TRAVELERS, WENT WITH A WINTER WEATHER
ADVISORY FOR NORTHWESTERN NORTH DAKOTA. THE NBM CHANCES FOR
ACCUMULATING ICE ARE SIMILAR TO CENTRAL AREAS OF NORTH DAKOTA,
MAINLY ALONG THE HIGHWAY 83 CORRIDOR, ALTHOUGH THERE IS LESS
CERTAINTY ON FREEZING RAIN VERSUS THE CHANGE OVER TO SNOW IN
THESE AREAS. THUS LEFT THEM OUT OF THE ADVISORY FOR NOW, AND
WILL HAVE TO BE MONITORED. MOST OTHER AREAS THAT SEE
PRECIPITATION WITH THIS WAVE COULD STILL SEE A WINTRY MIX, WITH
MAINLY RAIN EXPECTED IN THE FAR SOUTHWEST TO SOUTH CENTRAL. THE
CHANCE FOR A TENTH OF AN INCH OR MORE OF ICE ACCUMULATIONS FROM
FREEZING RAIN SUNDAY STILL REMAINS BELOW 10% FOR ALL AREAS.
SNOWFALL WITH THIS SYSTEM ALSO LOOKS TO REMAIN ON THE LIGHT SIDE
WITH THE CHANCE FOR AN INCH OR MORE ALSO LESS THAN 15%.
OTHERWISE LOOK FOR CONTINUED MILD TEMPERATURES IN THE WEST
SUNDAY WITH HIGHS IN THE 30S TO LOWER 40S, WITH 20S ACROSS THE
EAST. SNOW AND FREEZING RAIN WILL COME TO AN END ACROSS CENTRAL
AND EASTERN PORTIONS SUNDAY EVENING. LIGHT WINDS AND MILD
TEMPERATURES COULD PERHAPS PROVIDE SOME FOG SUNDAY NIGHT INTO
MONDAY MORNING, DEPENDING IF CLOUDS CAN CLEAR OR NOT BEHIND THE
CLIPPER SYSTEM.
THE HOLIDAY WEEK THEN LOOKS TO BE MAINLY DRY AND MILD ACROSS
MUCH OF THE CWA. WE SEE THIS PATTERN OF TRANSIENT RIDGE
FOLLOWED BY WEAK SHORTWAVE TROUGH FOLLOWED BY ANOTHER BRIEF
RIDGE THIS COMING WEEK, WITH THE WESTERLY FLOW ALOFT PROVIDING
MILD TEMPERATURES. MONDAY MAY STILL BE SLIGHTLY BELOW NORMAL
ACROSS EASTERN AREAS. WIDESPREAD HIGH TEMPERATURES IN THE 30S TO
LOWER 40S ARE THEN EXPECTED TUESDAY THROUGH THE END OF THE
WEEK, WITH MILD LOWS IN THE MID TEENS TO MID 20S. THIS COULD END
BEING A MILD CHRISTMAS FOR MANY GIVEN AVERAGE HIGH TEMPERATURES
ARE GENERALLY IN THE MID 20S WHILE AVERAGE LOW TEMPERATURES ARE
GENERALLY IN THE MID SINGLE DIGITS. CHANCES FOR PRECIPITATION
ARE FAIRLY LIMITED AT LEAST THROUGH CHRISTMAS DAY. LATER NEXT
WEEK CLUSTERS INDICATE A RETURN TO A BROAD TROUGHING PATTERN,
ALTHOUGH THEY ALSO INDICATE THIS COULD BE A SPLIT WAVE PATTERN,
LIMITED PRECIPITATION CHANCES. EVEN SO, NBM STILL SHOWING UP TO
10% CHANCES FOR ACCUMULATING SNOW IN A 24 HOUR PERIOD TO END THE
HOLIDAY WEEK INTO THE THE UPCOMING WEEKEND. ALTHOUGH NOT LARGE
AT THIS TIME, PERHAPS STILL WORTH MONITORING GOING FORWARD.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 957 PM CST SAT DEC 21 2024
VFR CONDITIONS TO BEGIN THE 06Z TAF PERIOD ACROSS THE FORECAST
AREA. FOG HAS DISSIPATED AROUND THE TURTLE MOUNTAINS, BUT LOW
STRATUS/FOG IS FORECAST TO DEVELOP HERE AFTER MIDNIGHT AND
SPREAD SOUTH INTO SUNDAY MORNING. THE SOUTHERN EXTENT OF THE FOG
SUNDAY MORNING IS NOT AS FAR SOUTH AS EARLIER RUNS OF THE SHORT
TERM MODELS AND FOG/STRATUS MAY STOP SHORT OF KBIS, IN ADDITION
TO KDIK. ON SUNDAY, BEGINNING AROUND 15 UTC, MIXED
PRECIPITATION WILL MOVE INTO NORTHWEST NORTH DAKOTA, TRACKING
SOUTHEAST THROUGH THE REMAINDER OF THE DAY. KXWA WOULD BE THE
MOST LIKELY TAF SITE TO RECEIVE FZRA SUNDAY, BUT A BRIEF PERIOD
CAN'T BE RULED OUT AT KDIK, KMOT AND KBIS. HOWEVER KDIK
PROBABILITIES ARE QUITE LOW, AND KMOT AND KBIS WOULD SEE A
BETTER CHANCE OF FZRA AND SNOW, OR POTENTIALLY ALL SNOW. IF ANY
PRECIP MAKES IT TO KJMS, IT WOULD BE AFT 00Z MONDAY. VARIABLE
SURFACE WINDS GENERALLY 5-15KTS SUNDAY MORNING, THEN MORE NORTH
TO NORTHWEST MONDAY AFTERNOON AND EVENING.
BIS WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NDZ001>004-009>011.
WINTER WEATHER ADVISORY FROM 9 AM CST /8 AM MST/ THIS MORNING
TO 6 PM CST /5 PM MST/ THIS EVENING FOR NDZ001-002-009-010-017-
018-031-032.
WINTER WEATHER ADVISORY FROM NOON CST /11 AM MST/ TODAY TO 9
PM CST /8 PM MST/ THIS EVENING FOR NDZ011-019>021-034-035.
UPDATE...HOLLAN
DISCUSSION...ANGLIN
AVIATION...TWH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page