909
FXUS63 KFGF 191004
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
404 AM CST TUE NOV 19 2024
KEY MESSAGES
- HEAVIEST RAINFALL END THIS MORNING.
- CHANGE OVER FROM RAIN TO SNOW REMAINS UNCERTAIN AS COLDER AIR
MOVES IN FROM THE WEST. ACCUMULATING SNOW AND GUSTY WINDS WILL
BRING WINTER IMPACTS LATE TODAY INTO WEDNESDAY.
- UNCERTAINTY STILL EXISTS IN THE SEVERITY AND LOCATION OF WINTER
IMPACTS, WITH THE MAIN UNCERTAINTY TIED TO THE STRENGTH AND
TRACK OF THE SYSTEM.
- HIGHEST CHANCES TO RECEIVE WINTER STORM IMPACTS ARE STILL OVER
THE DEVILS LAKE REGION WHERE PROBABILITIES OF 6 INCHES OF MORE
IS 70 PERCENT. THUS WARNING ISSUED THERE AS CHANGEOVER TO SNOW
FASTEST THERE. FARTHER EAST CONFIDENCE IN CHANGEOVER TIMING
AND IMPACTS ARE LESS UNCERTAIN
DISCUSSION
ISSUED AT 342 AM CST TUE NOV 19 2024
..SYNOPSIS
500 MB SHORT WAVE MOVING QUICKLY NORTH INTO CENTRAL MN AT 09Z.
THIS WAS NEAR EL PASO 24 HOURS AGO. RAIN ON THE NORTH AND WEST
SIDE OF THIS ADVANCING SHORT WAVE IS MOVING THRU THE FORECAST
AREA. UPPER LEVEL SYSTEM MOVES NORTH QUICKLY WITH DRIER AIR
MOVING INTO SE ND AND WC MN MIDDAY AND AFTN LIKELY ENDING THE
RAIN. A SECOND UPPER LEVEL SYSTEM GIVING SNOW TO MUCH OF
SASKATCHEWAN AT 09Z WILL MERGE WITH THE NORTHWARD MOVING SHORT
WAVE AND BY THIS AFTN A LARGER UPPER LOW CIRCULATION WILL BE
PRESENT OVER NORTHERN ND AND SOUTHERN MANITOBA. TONIGHT THIS
CIRCULATION WILL BE NEAR THE MN/ND/MB BORDER AND TRACK SOUTHEAST
WEDNESDAY INTO CENTRAL MN BY DAYS END.
.,TODAY-WEDNESDAY
STILL CONSIDERABLE UNCERTAINITY IN HOW THIS ALL PLAYS OUT THE
NEXT 24-36 HOURS. AS UPPER LEVEL SYSTEM MOVES INTO SOUTHEAST
MANITOBA MIDDAY DRIER AIR WILL WORK INTO SE ND/WC MN AND SHOULD
END THE RAIN. AS THIS SYSTEM MERGES WITH SYSTEM IN SASKATCHEWAN
TO FORM LARGER UPPER LOW, THE LOCATION OF THIS UPPER LOW WILL BE
CRITICAL IN THE DEGREE OF MOISTURE WRAPPING BACK SOUTH AND EAST
AROUND IT TONIGHT. ALSO THE DEGREE OF COOLING FROM THE WEST THIS
AFTN AND NIGHT WILL DETERMINE THE CHANGEOVER TO SNOW AND EXPECT
1-2 DEGREES WILL MAKE A BIG DIFFERENCE. EXPECTATION IS FOR RAIN
TO SNOW INTO DEVILS LAKE AREA, LANGDON ESPECIALLY LATE
MORNING/EARLY AFTN...AND THEN PROGRESSING EASTWARD INTO THE RRV
AND WESTERN MN THIS EVENING/TONIGHT. I COULD SEE AREAS EAST AND
WEST OF THE IMMEDIATE VALLEY COOLING FASTER THAN THE IMMEDIATE
LOCATIONS ALONG THE RED RIVER AS SOIL TEMPS AND OUR BARE FIELD
WITH DIRT KEEP TEMPS A TAD WARMER FOR A BIT LONGER THAN
EAST/WEST OF THE IMMEDIATE VALLEY. ALSO POSITION OF UPPER LOW
NEAR THE ND/MN/MB BORDER TONIGHT WILL KEEP THE WARMEST AIR RIGHT
NEAR IT KEEPING MORE RAIN CHANCE VS SNOW IN HALLOCK/ROSEAU THIS
EVENING BEFORE COLDER AIR MOVES IN LATE TONIGHT.
WEDNESDAY WILL SEE UPPER LOW MOVE SOUTHEAST. GLOBAL AND SHORT
TERM MODELS CONTINUE TO SHOW AN ENHANCED AREA OF PRECIPITATION
NEAR THE EAST EDGE OF THE RED RIVER VALLEY AND MODELS DO
INDICATE TRANSITORY BANDS OF 700 MB FRONTOGENESIS TO THE WEST OF
THE SOUTHEAST MOVING UPPER LOW.
BASED ON WPC QPF AND SLIGHTLY ADJUSTED SNOW TO LIQUID RATIOS
(BLEND OF NBM AND WPC) FORECAST SNOWFALL OF 5-8 DEVILS LAKE,
LANGDON AREAS WARRANTS A WARNING TO BE ISSUED AT THIS TIME AS
CHANGE OVER MAY OCCUR BEFORE NOON. SNOWBAND PROBABILITY TRACKER
PROTYPE PAGE FROM WPC INDICATES POTENTIAL BANDED SNOW THIS
AFTN/EVE IN THE AREA FROM LANGDON AND THE TURTLE MOUNTAINS INTO
SW MANITOBA WITH THIS LASTING INTO TONIGHT. HENCE HIGHER
SNOWFALL TOTALS THAT AREA.
FARTHER EAST AND SOUTH....UNCERTAINITY IN CHANGE OVER TIMING AND
AMOUNTS REMAIN HIGH ENOUGH SO THAT NO HEADLINES WERE ISSUED THIS
SHIFT. LIKELY ADVISORY BUT SOME CHANCE OF A FEW 6 INCH SNOWFALL
IN PARTS OF WESTERN MN IF SOME SHORT TERM MODELS ARE RIGHT. PLUS
IMPACTS ARE PAST 6 PM TODAY...AND COLLAB WITH MPX/ABR INDICATE
SIMILAR THINKING TO HOLD OFF WINTER HEADLINES FOR RRV AND
WESTERN MN TIL LATER.
WIND GUSTS DO LOOK A TAD LOWER THAN SHOWN YESTERDAY....AS FOCUS
OF 50-55 MPH WINDS ARE JUST WEST AND SOUTHWEST OF THE FCST AREA
MORE FROM WESTERN ND INTO CENTRAL AND SOUTHEAST SD. WIND
ADVISORY LEVELS MAY BE REACHED IN SE ND ESP WEDNESDAY BUT WITH
POSSIBLE WINTRY IMPACTS WOULD PREFER TO WAIT TO SEE WHICH ONE IS
MORE DOMINATE BEFORE ISSUING.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1140 PM CST MON NOV 18 2024
RAIN AND MVFR STRATUS CONTINUES TO SPREAD NORTHWARD, WITH
VISIBILITIES IN MODERATE RATE BELOW 6SM AT TIMES. THERE IS
STILL A STRONG SIGNAL FOR IFR CEILINGS TO DEVELOP TONIGHT AND
PERSIST THROUGH AT LEAST MIDDAY AS LOW LEVEL MOISTURE INCREASES
AND HIGH RESOLUTION MODELS STILL SHOW IFR VIS AT TIMES POSSIBLY
DUE TO ADDITIONAL LIGHT FOG DEVELOPMENT WITH RAIN. RAIN SNOW
TRANSITION MAY OCCUR BY LATE TUESDAY MORNING AT KDVL, HOWEVER
THERE MAY BE A LULL IN PRECIPITATION (OR PRECIP RATES) DURING
THE AFTERNOON BEFORE A SECONDARY REGION OF PRECIPITATION AND
RAIN TO SNOW TRANSITION OCCURS TUESDAY EVENING ACROSS THE
REGION. WINDS EVENTUALLY SHIFT TO THE WEST AND INCREASE AS THE
LOW PRESSURE SYSTEM EVOLVES OVER OUR REGION AND THIS COULD
RESULT IN BLOWING SNOW WHILE NEW SNOW IS FALLING (CHANCE BETTER
AFTER 00Z).
FGF WATCHES/WARNINGS/ADVISORIES
ND...WINTER STORM WARNING FROM NOON TODAY TO 6 PM CST WEDNESDAY FOR
NDZ006-007-014-015.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST
WEDNESDAY FOR NDZ024-026-028-054.
MN...NONE.
DISCUSSION...RIDDLE
AVIATION...DJR
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