944
FXUS63 KBIS 262010
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
210 PM CST SUN JAN 26 2025
KEY MESSAGES
- SEASONABLY MILD AND WINDY TONIGHT THROUGH TUESDAY.
- NOT AS WINDY THROUGH THE REST OF THE WEEK, WITH ABOVE NORMAL
TEMPERATURES CONTINUING, ESPECIALLY SOUTHWEST AND SOUTH
CENTRAL.
- NO GREATER THAN A 10 PERCENT CHANCE OF PRECIPITATION THROUGH
FRIDAY.
- LIKELY TRANSITION TO A COLDER AND MORE ACTIVE PATTERN THIS
WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 210 PM CST SUN JAN 26 2025
SYNOPTIC FEATURES THAT ARE EXERTING THE GREATEST INFLUENCE ON
NORTHERN PLAINS WEATHER THIS AFTERNOON INCLUDE BROAD SURFACE HIGH
PRESSURE CENTERED OVER THE CENTRAL PLAINS AND A NORTHERLY
ANTICYCLONIC FLOW ALOFT. WARMING OF THE LOW LEVELS IS BEING DRIVEN
BY CHINOOK FLOW OFF THE CANADIAN ROCKIES, AND A SURFACE LOW
APPROACHING HUDSON BAY IS TIGHTENING THE SURFACE PRESSURE GRADIENT.
THE REST OF THE AFTERNOON WILL REMAIN MOSTLY SUNNY AND BREEZY, WITH
TEMPERATURES TOPPING OUT IN THE 20S WHERE THERE IS APPRECIABLE SNOW
COVER, AND LOWER TO MID 30S WHERE THERE IS NOT.
FLOW ALOFT WILL TURN NORTHWESTERLY TONIGHT AS RISING HEIGHTS ALONG
WITH A STRONG DEEP-LAYER GRADIENT WILL ALLOW A 50-60 KT WESTERLY LOW-
LEVEL JET TO TRANSLATE THROUGH THE REGION FROM NORTH TO SOUTH. THIS
WILL KEEP WINDY CONDITIONS AND MILD TEMPERATURES THROUGH THE
OVERNIGHT. FORECAST LOWS AROUND 20 COULD OCCUR DURING THE LATE
EVENING, WITH SLOWLY RISING TEMPERATURES EXPECTED AS WINDS PICK UP
LATER TONIGHT. MOST AREAS WILL SEE SURFACE WINDS AROUND 15-25 MPH
OVERNIGHT, BUT HIGHER TERRAIN AREAS COULD SEE ISOLATED GUSTS AS HIGH
AS 45 MPH. DETERMINISTIC GUIDANCE ALSO SHOWS A WEAK MID LEVEL
SHORTWAVE EMBEDDED IN THE NORTHWEST FLOW MOVING SOUTH FROM SOUTHERN
MANITOBA THROUGH EASTERN NORTH DAKOTA TONIGHT. A FEW RUNS OF THE RAP
AND A COUPLE OTHER CAMS HAVE HINTED AT LIGHT PRECIPITATION
ASSOCIATED WITH THIS WAVE, WITH ISENTROPIC ASCENT ALSO ASSISTING IN
LIFT. HOWEVER, RAP SOUNDINGS FROM RUNS THAT INCLUDED THIS
PRECIPITATION SHOWED 10-15 KFT CEILINGS AND A LACK OF CONSISTENCY IN
COLUMN SATURATION ABOVE THE COULD BASE. IT THEREFORE SEEMS HIGHLY
UNLIKELY THAT ANY PRECIPITATION WILL REACH THE GROUND, WHICH IS WHAT
THE MAJORITY OF GUIDANCE IS PROJECTING. EVEN IF PRECIPITATION DOES
REACH THE SURFACE, ONLY TRACE AMOUNTS AT MOST CAN BE EXPECTED.
HOWEVER, THE MOST LIKELY PRECIPITATION TYPE WOULD BE FREEZING RAIN
(REALLY MORE LIKE "FREEZING SPRINKLES") GIVEN FORECAST TEMPERATURES
ALOFT ABOVE FREEZING. THE PROBABILITY OF EVEN JUST MINOR IMPACTS
THOUGH IS NEAR ZERO.
THE MAIN STORY FOR MONDAY THROUGH THURSDAY WILL BE SEASONABLY MILD
TEMPERATURES AS UPPER LEVEL RIDGING OVER THE PACIFIC NORTHWEST
PUSHES UP AGAINST DEEP TROUGHING OVER EASTERN CANADA. NBM
TEMPERATURE SPREAD THROUGH THURSDAY IS LOW AND KEEPS ALL OF WESTERN
AND CENTRAL NORTH DAKOTA ABOVE AVERAGE. AREAS SOUTH AND WEST OF THE
MISSOURI RIVER, AS WELL AS SOUTH OF INTERSTATE 94 EAST OF THE RIVER,
ARE FAVORED TO SEE HIGHS MOSTLY IN THE 40S. THIS IS ESPECIALLY TRUE
WHERE THERE IS LITTLE TO NO SNOW COVER, AND COULD EASILY SEE A
COUPLE DAYS WITH HIGHS ABOVE 50 AT SUCH LOCATIONS. FOR MONDAY AND
TUESDAY, THE HIGH TEMPERATURE FORECAST WAS RAISED TO AT LEAST THE
75TH PERCENTILE WHERE OBSERVED/ANALYZED SNOW DEPTH IS LESS THAN 2
INCHES. AREAS FARTHER TO THE NORTH ARE STILL LIKELY TO SEE 30S FOR
HIGHS MONDAY AND TUESDAY, BUT COULD FALL BACK TO JUST BELOW FREEZING
FOR WEDNESDAY AND THURSDAY AS A COUPLE OF VORT STREAKS CLIPPING THE
RED RIVER VALLEY PUSH BACK ON THE WESTERN RIDGE. IT WILL REMAIN
WINDY MONDAY THROUGH TUESDAY, WITH LOWER CONFIDENCE IN SURFACE WIND
INTENSITY THEREAFTER (BUT MORE LIKELY TO BE NOT AS WINDY). THERE ARE
NO MENTIONABLE CHANCES FOR PRECIPITATION THROUGH THE UPCOMING WORK
WEEK.
ENSEMBLE SPREAD IN ALL FIELDS GROWS RAPIDLY ON FRIDAY, ESPECIALLY IN
HIGH TEMPERATURES WITH THE MIDDLE 50TH PERCENTILE SPREAD IN THE NBM
AROUND 20 DEGREES FAHRENHEIT. THE WARMER SOLUTION WOULD KEEP THE
MILDER TREND GOING, WHILE THE COLDER SOLUTION WOULD RETURN
TEMPERATURES TO NEAR NORMAL SOUTH AND BELOW NORMAL NORTH. ENSEMBLE
CLUSTER ANALYSIS IS NEARLY EVENLY SPLIT ON THE COLD VS. WARM OUTCOMES
FOR FRIDAY. THERE IS A WIDE VARIETY OF OUTCOMES IN ENSEMBLE GUIDANCE
FOR THE WEEKEND INTO EARLY NEXT WEEK, BUT ALL SOLUTIONS POINT TOWARD
A COOLING TREND AND A RETURN OF CHANCES FOR SNOW. 6-HOUR NBM
PROBABILITIES FOR MEASURABLE SNOW ONLY MAX OUT AT AROUND 30 PERCENT
SATURDAY THROUGH MONDAY, BUT THESE VALUES ARE SIMILAR TO GLOBAL
ENSEMBLE PROBABILITIES FOR AT LEAST ONE INCH OF SNOW OVER ANY GIVEN
24-HOUR PERIOD DURING THAT TIMEFRAME.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 210 PM CST SUN JAN 26 2025
VFR CONDITIONS AND WESTERLY WINDS AROUND 15-20 KTS WITH GUSTS
TO 25-30 KTS ARE EXPECTED THROUGH THE FORECAST PERIOD. LOW
LEVEL WIND SHEAR WILL IMPACT ALL TERMINALS LATE THIS EVENING
THROUGH EARLY MONDAY MORNING, WITH 50-55 KT WEST-NORTHWEST
WINDS AROUND 1,000 FT ABOVE THE SURFACE.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HOLLAN
AVIATION...HOLLAN
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