434
FXUS63 KFGF 170926
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
326 AM CST SUN NOV 17 2024
KEY MESSAGES
- LIGHT RAIN WILL MIX WITH SNOW THIS MORNING IN THE DEVILS LAKE
BASIN, WITH A CHANCE FOR FREEZING DRIZZLE.
- WIDESPREAD RAIN IS EXPECTED TO MOVE THROUGH THE FORECAST AREA
MONDAY EVENING INTO TUESDAY.
- ACCUMULATING SNOW AND GUSTY WINDS TUESDAY NIGHT AND
WEDNESDAY, BRINGING MINOR TO MODERATE IMPACTS TO THE FORECAST
AREA.
DISCUSSION
ISSUED AT 326 AM CST SUN NOV 17 2024
..SYNOPSIS
UPPER LEVEL WAVE CONTINUES TO MOVE THROUGH WESTERN NORTH DAKOTA THIS
MORNING AND LIFTS THROUGH CANADA. LIGHT RAIN AND SNOW SHOWERS
CONTINUE TO SHIFT THROUGH THE TURTLE MOUNTAINS AND INTO THE DEVILS
LAKE BASIN THROUGH THE MID MORNING. A BRIEF RIDGE BUILDS INTO THE
REGION BY THIS AFTERNOON AND CONTINUES INTO THE EARLY PORTION OF
MONDAY BEFORE FLOW BECOMES SPLIT AND TWO SYSTEMS INTERACT ACROSS OUR
AREA. MONDAY AFTERNOON AND EVENING A STRONGER 500MB SYSTEM MOVES
FROM THE SOUTHWESTERN UNITED STATES INTO OUR FA, BRINGING WIDESPREAD
PRECIPITATION THROUGH TUESDAY. A SECONDARY SYSTEM MOVES THROUGH THE
NORTHERN ROCKIES AND HELPS TO AMPLIFY THE 500MB SYSTEM FROM THE
SOUTHWEST US. THE DEEPENING SURFACE LOW PRESSURE SHIFTS THROUGH OUR
FORECAST AREA TUESDAY EVENING THROUGH WEDNESDAY BRINGING COLDER AIR
ON THE BACK EDGE. UNCERTAINTY ARISES WITH THE TIMING OF THE
TRANSITION FROM RAIN TO SNOW, HOW STRONG OF CAA WE GET, AND HOW
STRONG THE WINDS ARE ON THE BACK EDGE OF THE SYSTEM. NONE THE LESS,
THE COLDER AIR WILL HELP TRANSITION THE RAIN TO SNOW AND THERE IS
THE POTENTIAL FOR WINTERY IMPACTS ACROSS THE FORECAST AREA. POST MID
WEEK SYSTEM, WE SEE DRYING CONDITIONS AND RIDING ACROSS THE NORTHERN
PLAINS.
..PRECIPITATION THIS MORNING
AN UPPER LEVEL WAVE CONTINUES TO SHIFT THROUGH ND AND INTO SOUTHERN
CANADA THIS MORNING BRINGING PRECIPITATION TO PORTIONS OF THE AREA.
LIGHT RAIN CONTINUES TO BE REPORTED FOR AREAS NORTH OF THE RED RIVER
VALLEY IN SOUTH CENTRAL MANITOBA. COLDER AIR IS BEING OBSERVED
MOVING IN FROM THE NW HELPING TO CHANGE OVER THE PRECIPITATION TO
SNOW. THIS CHANGE OVER TO SNOW IS PREDOMINATELY IN THE DEVILS LAKE
BASIN. TEMPERATURES IN THE BASIN ARE IN THE LOW 30S, WITH THE MID TO
UPPER 30S IN THE RED RIVER VALLEY. SOME ISOLATED SHOWERS ARE
POSSIBLE IN THE NORTHERN RED RIVER VALLEY AND NORTHERN MN THROUGH
THE MID MORNING, WITH A BRIEF INTRODUCTION OF SNOW AT TIMES TO MIX
IN. LITTLE TO NO ACCUMULATION IS EXPECTED. ATMOSPHERIC SOUNDINGS IN
NE ND AND INTO FAR NW MN INDICATE DRIER AIR MOVING IN THROUGH THE
MID LEVELS, ALONG WITH MOISTURE CONTINUING AT THE SURFACE. LACK OF
ICE CRYSTALS ALOFT, LOW LEVEL SATURATION, AND TEMPERATURES HOVERING
AROUND FREEZING BRING A SLIGHT CHANCE (LESS THAN 20%) FOR FREEZING
DRIZZLE TO MIX IN. IF THIS WHERE TO OCCUR MINOR IMPACTS TO TRAVEL
WOULD HAPPEN. CURRENT OBSERVATIONS AROUND THE AREA INDICATE NO
FREEZING DRIZZLE AT THIS TIME. THE DRY AIR ALOFT AND SATURATION NEAR
THE SURFACE LINGER THROUGH THE MID MORNING HOURS. THUS THE SLIGHT
CHANCE FOR FREEZING DRIZZLE LINGERS THROUGH THE MID MORNING BEFORE
CONDITIONS FULLY DRY OUT IN THE LOWER LEVELS. WE WILL CONTINUE TO
MONITOR CONDITIONS THROUGH THE MORNING.
..WIDESPREAD RAIN
AFTER A BRIEF BREAK IN ACTIVITY SUNDAY AFTERNOON THROUGH MONDAY
MORNING, WE INTRODUCE ANOTHER SYSTEM INTO THE AREA MONDAY EVENING
INTO TUESDAY. STRONG WARM AIR ADVECTION, THANKS TO A STRONG LOW
LEVEL JET, PUSHES INTO THE FORECAST AREA MONDAY EVENING BRINGING
WIDEPSREAD SYNOPTIC FORCED RAIN TO THE AREA. RAIN MAY BE MODERATE
AT TIMES AS WEAK FRONTOGENTIC FORCING OVERLAPS WITH THE SYNOPTIC
FORCING BRINGING UNORGANIZED BANDED PRECIPITATION. RAIN CONTINUES
THROUGH THE EVENING HOURS BEFORE THE SYSTEM STARTS TO USHER IN CAA
FROM SOUTHERN CANADA HELPING TO TRANSITION THE RAIN OVER TO SNOW.
THE PROBABILITY TO SEE OVER AN INCH OF QPF FOR 24 HOURS IS 40% FOR
AREAS IN THE RED RIVER VALLEY POINTS EASTWARD, WITH LOWER CHANCES IN
THE DEVILS LAKE BASIN.
..MINOR TO MODERATE WINTER IMPACTS
TUESDAY NIGHT AND INTO WEDNESDAY WE START TO TRANSITION RAIN OVER TO
SNOW FOR THE AREA, STARTING FIRST IN THE DEVILS LAKE BASIN. THERE IS
LOW CONFIDENCE IN THE EXACT TIMING OF THE COLD AIR ARRIVING IN THE
BASIN AND HOW STRONG IT WILL BE. WINDS WILL BE DRIVEN PREDOMINANTLY
BY THE STRONG PRESSURE GRADIENTS ACROSS THE AREA, WITH CAA PLAYING A
SMALLER ROLE. WINDS HAVE THE POTENTIAL TO GUST UP TO 40KTS WITHIN
THE RED RIVER VALLEY POINTS WESTWARD. THE STRONGEST OF WINDS ARE
LOOKING TO BE IN THE JAMES RIVER VALLEY POINTS WEST WHERE THE CAA
WILL BE STRONGER. STRONG WINDS COMBINED WITH FALLING SNOW MAY CREATE
IMPACTS TO VISIBILITY. PROBABILITIES OF SEEING OVER AN INCH OF SNOW
ARE 40% WITHIN THE RED RIVER VALLEY AND 60% IN THE DEVILS LAKE
BASIN. AS IT LOOKS NOW, THERE IS ABOUT A 20 PERCENT CHANCE FOR
MODERATE IMPACTS (WINTER STORM), ALTHOUGH IT IS GREATEST WEST OF THE
RRV.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1010 PM CST SAT NOV 16 2024
MVFR TO HIGH-END IFR CONDITIONS WILL PREVAIL FOR THE FIRST HALF
OF THE TAF PERIOD. RAIN AND SNOW WILL CONTINUE THROUGH AT LEAST
12Z, POTENTIALLY IMPACTING DVL/GFK/TVF/BJI, BUT ACCUMULATIONS ON
THE GROUND ARE UNLIKELY. THERE IS A VERY LOW CHANCE (10%) FOR
FZDZ AT DVL BETWEEN 08-14Z BUT THE PROBABILITY FOR THIS IS AGAIN
VERY LOW. CEILINGS WILL BEGIN TO RISE AROUND 12Z FROM THE WEST
TO THE EAST, GIVING WAY TO VFR CONDITIONS AND PERSISTENT
WESTERLY WINDS TOMORROW AFTERNOON.
FGF WATCHES/WARNINGS/ADVISORIES
ND...NONE.
MN...NONE.
DISCUSSION...SPENDER
AVIATION...PERROUX
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