741
FXUS63 KFGF 190540
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1140 PM CST MON NOV 18 2024
KEY MESSAGES
- WIDESPREAD RAINFALL OVERSPREADS EASTERN NORTH DAKOTA AND
MINNESOTA TONIGHT INTO TUESDAY.
- ACCUMULATING SNOW AND GUSTY WINDS WILL BRING WINTER IMPACTS
TUESDAY 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, BUT EXPANDED THIS A BIT ON THE EASTERN
AND SOUTHERN EDGES TO ENCOMPASS A SLIGHTLY WIDER AREA FOR THE
UNCERTAINTY OF THE SNOW/WIND/BLOWING SNOW POTENTIAL.
UPDATE
ISSUED AT 1025 PM CST MON NOV 18 2024
RAIN CONTINUES TO SPREAD NORTH AND RADAR RETURNS HAVE NOW
REACHES THE HIGHWAY 2 CORRIDOR. MINOR NEAR TERM ADJUSTMENTS WERE
MADE TO CAPTURE CURRENT TIMING COVERAGE, OTHERWISE FORECAST
REMAINS ON TRACK FOR THE REST OF THE EVENING INTO THE OVERNIGHT
HOURS. NO CHANGES AT THIS POINT FOR THE ONGOING WINTER STORM
WATCH, WITH ONLY SOME NEW DATA JUST NOW STARTING TO ROLL IN AND
DECISIONS ON UPGRADES (OR NOT) BEING HELD OFF UNTIL LATER
TONIGHT.
UPDATE
ISSUED AT 725 PM CST MON NOV 18 2024
FORECAST IS ON TRACK, WITH FEW ADJUSTMENTS NEEDED DURING THIS
UPDATE CYCLE IN THE NEAR TERM. RAIN AS SPREAD INTO THE SOUTHERN
RED RIVER VALLEY AND WEST CENTRAL MN (SURFACE OBS 3-6SM WHERE
RETURNS ARE 35DBZ+ ON RADAR). THIS MATCHES THE TIMING/COVERAGE
PROGRESSION FROM HREF AND CURRENT FORECAST WELL.
DISCUSSION
ISSUED AT 342 PM CST MON NOV 18 2024
..SYNOPSIS
THE SURFACE LOW ASSOCIATED WITH THE NEXT STORM SYSTEM IS
CURRENTLY OVER CENTRAL KANSAS, BUT ITS RAIN SHIELD HAS MOVED ALL
THE WAY NORTH INTO SOUTHERN MINNESOTA. SEEING LIGHT RAIN
REPORTED ALREADY AS FAR NORTH AS REDWOOD FALLS MINNESOTA. THIS
SURFACE LOW IS EXPECTED TO TRACK NORTHWARD TO SOUTH CENTRAL
MINNESOTA BY TUESDAY MORNING, THEN NORTHWARD TO AROUND WINNIPEG
BY EARLY TUESDAY EVENING. THEN IT APPEARS THERE WILL BE AT LEAST
A 12 HOUR PERIOD (TUESDAY NIGHT) THAT IT REMAINS IN PLACE,
BEFORE IT BEGINS TO SLOWLY WEAKEN ITS GRIP ON THE NORTHERN
PLAINS (AS IT EXITS TO THE EAST-SOUTHEAST). 500MB RIDGING BUILDS
IN BEHIND THIS SYSTEM FOR LATE WEEK INTO THE WEEKEND, WITH
A WEAK CLIPPER SYSTEM POSSIBLE LATE WEEKEND INTO EARLY NEXT
WEEK.
..RAINFALL TONIGHT INTO TUESDAY
AS THE SURFACE LOW OVER KANSAS LIFTS INTO SOUTH CENTRAL
MINNESOTA BY TUESDAY MORNING, A STRONG SOUTHERLY MOISTURE SURGE
WILL CONTINUE TO STREAM NORTHWARD THROUGH MINNESOTA. HAVE BEEN
LOOKING AT A WIDESPREAD WETTING RAIN ACROSS THE ENTIRE FA FOR
TONIGHT THROUGH TUESDAY. THE LATEST NBM SHOWS ALMOST A 100
PERCENT PROBABILITY FOR RAINFALL AMOUNTS OVER 0.50 INCHES EAST
OF THE RRV TO ABOUT A 70 PERCENT CHANCE TO THE WEST.
PROBABILITIES FOR 1 INCH OR MORE OF RAINFALL HAVE SHOT UP TO
AROUND 70 PERCENT EAST OF THE RRV, BUT THAT TAPERS OFF QUICKLY
TO THE WEST OF THE VALLEY. SO QUITE A BIT OF RAIN IS ANTICIPATED
OVER THE NEXT 24 TO 30 HOURS.
..WINTER IMPACTS TUESDAY INTO WEDNESDAY
AS THE SURFACE LOW LIFTS THROUGH THE EASTERN FA ON TUESDAY AND
TRACKS TOWARD WINNIPEG, THERE SHOULD BE A TRANSITION FROM RAIN
TO SNOW IN SOME AREAS. THIS SHOULD OCCUR FIRST ACROSS THE DEVILS
LAKE REGION, BUT THE LATEST HREF IS SHOWING A POTENTIAL CHANGE
OVER IN THE "HIGHER" ELEVATIONS WEST OF THE RRV FROM FINLEY TO
WALHALLA NORTH DAKOTA. LOOKING AT INDIVIDUAL MODEL SOUNDINGS,
MANY ARE KEEPING IT FAIRLY WARM THROUGH THIS TIME PERIOD, SO AM
MORE CONFIDENT IN THE EARLIER CHANGE OVER ACROSS THE DEVILS LAKE
REGION, RATHER THAN FURTHER EAST. WIND SPEEDS INCREASE DURING
THE DAY TUESDAY, ESPECIALLY ALONG AND SOUTH OF A DEVILS LAKE TO
FERGUS FALLS LINE. THE SNOW COMBINING WITH THE WIND SHOULD BEGIN
TO CREATE SOME VISIBILITY PROBLEMS. THE PROBABILITY FOR MORE
THAN 6 INCHES OF SNOW DECREASED SOMEWHAT TODAY, BUT REMAINS THE
HIGHEST ACROSS THE DEVILS LAKE REGION. BASICALLY IT NOW SHOWS
ABOUT A 50 PERCENT PROBABILITY IN THE DL REGION FOR THE 6 INCHES
OR MORE, WITH THE HIGHEST POTENTIAL RIGHT AROUND THE TURTLE
MOUNTAINS. THE SLIGHTLY FURTHER NORTH SURFACE LOW TRACK, TO
AROUND WINNIPEG, MAY PLAY PARTLY INTO THIS. THE ONLY OTHER
CHANGE THIS AFTERNOON WAS SEEING PROBABILITIES FOR 4 INCHES OR
MORE OF SNOW INCREASE JUST EAST OF THE RRV.
..UNCERTAINTY IN THE STRENGTH AND TRACK OF THE SYSTEM
THIS STORM SYSTEM HAS ALWAYS APPEARED TO BE ONE MOVING
NORTHWARD OUT OF NORTH TEXAS, COMBINING AT SOME POINT WITH
ANOTHER WAVE OUT OF CANADA. DEALING WITH WAVE INTERACTIONS IS
ALWAYS TRICKY, AND THAT REMAINS THE CASE WITH THIS STORM
SYSTEM. IF THE SURFACE LOW HOLDS LONGER NORTH OF THE CANADIAN
BORDER, IT IS POSSIBLE MORE OF THE SNOW WILL HOLD TO THE NORTH
AS WELL. IF MORE COLD AIR CAN GET DRAWN INTO IT, MORE SNOW COULD
STILL FALL ACROSS THE DEVILS LAKE REGION. IN ADDITION TO THE
ABOVE MENTIONED UNCERTAINTIES, THERE IS ALSO THE QUESTION OF HOW
LOW VISIBILITIES WILL GET WITH THE WIND DRIVEN SNOW. THE
CURRENT WIND FORECAST FOR THE DEVILS LAKE THROUGH SOUTHERN RRV
(HIGHER WIND CORRIDOR), STILL LOOKS TO HAVE A GUST POTENTIAL TO
40 TO 50 MPH.
..KEPT THE WINTER STORM WATCH BUT EXPANDED IT SLIGHTLY
WITH THE HIGH AMOUNT OF UNCERTAINTY, DID NOT WANT TO SWITCH TO
WARNINGS QUITE YET. HOWEVER, DID WANT TO EXPAND THE WATCH AREA
SLIGHTLY. WITH THE STRONG WIND POTENTIAL AND SLIGHTLY BELOW
WARNING CRITERIA SNOW A LITTLE BROADER, WENT AHEAD AND EXPANDED
THE WATCH TO INCLUDE A FEW MORE COUNTIES TO THE SOUTH AND
EAST. AT SOME POINT, WILL ALSO NEED A WINTER WEATHER ADVISORY,
BUT FELT THAT COULD WAIT AT THIS POINT TOO.
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 WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR NDZ006-007-014-015-024-026-028-054.
MN...NONE.
UPDATE...DJR
DISCUSSION...GODON
AVIATION...DJR
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