717
FXUS63 KFGF 231748
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1148 AM CST MON DEC 23 2024
KEY MESSAGES
- FOG MAY BE PREVALENT FOR AN EXTENDED PERIOD THIS WEEK,
ESPECIALLY IN NORTHEAST ND.
- AS WE GRADUALLY WARM UP, NEXT SYSTEM MOVES UP FRIDAY AND GIVES
MAJORITY LIGHT RAIN. BUT WILL NEED TO MONITOR SURFACE TEMPS
CLOSELY.
UPDATE
ISSUED AT 1057 AM CST MON DEC 23 2024
EXPANDED THE DENSE FOG ADVISORY THROUGH THE REST OF THE RED
RIVER VALLEY WITH SEVERAL SURFACE OBSERVATIONS AND WEBCAMS
INDICATING THE PRESENCE OF VISIBILITY QUARTER MILE OR LESS IN
THESE AREAS.
MORNING GUIDANCE SUGGESTS SURFACE HIGH PRESSURE HOUSING FOG/LOW
STRATUS SHIFTS EAST INTO THE RED RIVER VALLEY TODAY, WHICH
SHOULD HELP CONTINUE FOG.
INTERESTING TO SEE NDAWN'S SURFACE PRESSURE READINGS ABOUT 2-3
MB HIGHER THAN WHAT MOST OTHER GUIDANCE/OBJECTIVE ANALYSIS IS
SHOWING IN THE DEVILS LAKE AND LOWER SOURIS RIVER BASINS. THIS
MAY BE A TESTAMENT TO INDICATING THAT THERE IS A STRONGER 'LID'
OUT THERE THAN WHAT IS CURRENTLY BEING ADVERTISED BY GUIDANCE.
THIS MAY ALSO HELP EXPLAIN THE MARKEDLY COLDER AIR THAT IS
'TRAPPED' WITHIN THE SURFACE HIGH PRESSURE.
HOWEVER THERE IS STILL SOME QUESTION ON IF FOG CAN LIFT/THIN
THIS AFTERNOON, BUT RECENT OBSERVATIONAL TRENDS ARE SUGGESTING
THIS MAY NOT BE FAVORED. GUIDANCE OFFERS A STRONG SIGNAL OF
WARM, MOIST ADVECTION INTO OUR AREA FROM THE WEST TONIGHT, WHICH
WOULD CONTINUE FOG AS WELL.
ELSEWHERE, FOG AND/OR MIST OR VERY LIGHT SNOW REMAINS LIABLE TO
OCCUR. GIVEN SHORTWAVE UPPER RIDGING ALOFT, FORCING FOR
SUSTAINED FREEZING DRIZZLE MAY BE HARD TO COME BY DESPITE LOW
LEVEL SATURATION IN THE SUPERCOOLED REGION.
ULTIMATELY, LOOKING AT A DREARY, FOGGY DAY AND NIGHT WITH SOME
CHANCE FOR LIGHT FREEZING MIST AND/OR LIGHT SNOW.
UPDATE ISSUED AT 648 AM CST MON DEC 23 2024
THICKER FOG EXPANDING SOUTHWARD INTO VALLEY CITY IN THE HOUR. SO
EXTENDED DENSE FOG ADV INTO BARNES COUNTY AND GRIGGS COUNTY AS
BIS UPDATED FOG ADV AS WELL TO GO SOUTH. OTHERWISE CLOUDY SKY
WITH LOW CLOUDS HAVING COVERED ALL BUT FAR SOUTHEAST FCST AREA.
THE LIGHT SNOW IN THE FERGUS FALLS AND ELBOW LAKE AREA WITH THE
UPPER WAVE MOVED OUT BY 1230 UTC.
DISCUSSION
ISSUED AT 337 AM CST MON DEC 23 2024
..SYNOPSIS
WE TRANSITION TO A WEST-SOUTHWEST TO MORE SOUTH-SOUTHWEST FLOW
AT 500 MB THIS WEEK. THIS WILL LEAD TO INCREASING WARMTH THRU
THE WEEK, PEAKING FRIDAY. SYSTEM MOVING NORTH-NORTHEAST IN THE
FLOW WILL MOVE THROUGH GIVING A CHANCE OF PRECIPITATION, WITH
INDICATIONS ARE TO BE RAIN. BUT WILL NEED TO MONITOR TEMP
GUIDANCE.
..THIS WEEK
SHORT WAVE WHICH BROUGHT THE ICING ISSUES TO NORTHWEST INTO
CENTRAL IS MOVING OUT. A BIT OF FREEZING DRIZZLE DID SNEAK INTO
FAR SE ND MIDNIGHT-2 AM BUT HAS SINCE TURNED TO LIGHT SNOW AND
IS MOVING OUT. LIGHT SNOW PATCHES IN WC MN AS WELL. ATMOSPHERIC
COLUMN IS COOLING THIS MORNING AS COLDER AIR MOVES SOUTH.
HIGH PRESSURE WILL MOVE EAST THRU SOUTHERN MANITOBA AND INTO NW
ONTARIO BY THIS EVENING. WEAK NORTH SFC FLOW WITH THIS BUT
SOUNDINGS SHOW A LOT OF LOW LEVEL MOISTURE. THUS TRENDED
CLOUDIER THAN NBM AND OTHER GUIDANCE SHOWS FOR CLOUDS. I DID
KEEP SOME CHANCE OF SCATTERED CLEARING IN NW MN TODAY MAINLY FOR
COLLABORATION PURPOSES BUT LOOKING UPSTREAM ALL I SEE IS
CLOUDS. FOG....SOME DENSE IS IN NORTHEAST ND AND HAS BEEN
SPREADING SOUTH, PARTICULARLY IN AREAS FROM CAVALIER AND LANGDON
TO DEVILS LAKE AND NEW ROCKFORD WHERE WEBCAMS AND AWOS DATA
SHOWS DENSE FOG IS WIDESPREAD. COORD WITH BIS AND HAVE DENSE FOG
ADV THRU NOON THIS AREA. DID KEEP MENTION OF FOG MOST OF E ND
AND RRV THRU THE DAY....BUT AS USUAL UNCERTAINTY EXISTS IN
THIS. COULD WELL BE SOCKED IN ALL DAY ESP IN DVL BASIN. QUESTION
OF FREEZING DRIZZLE. DISCUSSED WITH BIS AND LOOKS LIKE SOUNDING
WHILE SUPPORTS THE CLOUDS AND FOG WITH LIGHT WINDS IN THE
INVERSION UP THRU 900 MB UNSURE IF THERE IS ANY LIFT IN THIS
LAYER OR ABOVE FOR ANY DRIZZLE. SO FOR THIS REASON KEPT DRIZZLE
OUT OF THE FCST. DID MENTION IN NPW THOUGH ICE CRYSTALS MAY
DEPOSIT ON SURFACES CAUSING THEM TO BE SLICK.
FOR THE WEEK AS WE GRADUALLY WARM UP....CLOUDS AND FOG CHANCES
MAY WELL LINGER EVERY DAY.
FOR FRIDAY...ENSEMBLES PAINT A HIGHER CHANCE FOR LIGHT RAIN TO
MOVE NORTH INTO THE AREA DURING THE DAY. GFS AND ENSEMBLES A BIT
HEAVIER WITH PRECIP (0.15 GEFS MEAN) VS ECMWF/CANADIAN GLOBAL.
BUT IF LOW LEVEL TEMPS REMAIN AS THEY ARE FORECAST WILL BE WARM
ENOUGH FOR RAIN AS TEMPS ABOVE FREEZING DURING THE MAJORITY IF
NOT ALL OF THE PRECIP TIME. BUT THIS WILL NEED TO BE MONITORED
IN THE COMING DAYS. ALSO ROAD TEMPS TOO THEY SHOULD RISE SOME AS
TEMPS MODERATE BUT MAY BE CLOSE.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1142 AM CST MON DEC 23 2024
LIFR CONDITIONS HAVE PREVAILED THIS MORNING, AND WILL CONTINUE
INTO THE AFTERNOON. FOG HAS FILLED IN ACROSS THE REGION,
REDUCING VISIBILITY AT ALL TAF SITES. THIS FOG WILL LIKELY
CONTINUE THROUGHOUT THE ENTIRE TAF PERIOD, ALBEIT VISIBILITIES
MAY IMPROVE SLIGHTLY THIS AFTERNOON, PARTICULARLY AT KDVL. AFTER
SUNSET, FOG IS EXPECTED TO THICKEN AGAIN. VISIBILITIES IN THE
TAFS WERE KEPT AT 1 MILE FOR THE OVERNIGHT PERIOD AT MOST SITES.
HOWEVER, AS CONFIDENCE INCREASES IN THE TIMING AND LOCATION OF
FOG DEVELOPMENT THIS EVENING INTO THE OVERNIGHT, VISIBILITIES
WILL LIKELY NEED TO BE LOWERED AT CERTAIN SITES IN THE NEXT SET
OF TAFS. WINDS START THE PERIOD VARIABLE AND UNDER 5 KNOTS,
TURNING SOUTHERLY TONIGHT, INCREASING UP TO 12 KNOTS.
FGF WATCHES/WARNINGS/ADVISORIES
ND...DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ001>004-
007-029.
UPDATE...CJ/RIDDLE
DISCUSSION...RIDDLE
AVIATION...RAFFERTY
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