488
FXUS65 KGJT 181743
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1143 AM MDT FRI OCT 18 2024
KEY MESSAGES
- HEAVY SNOWFALL IS EXPECTED ACROSS THE EASTERN UTAH MOUNTAINS
AND SOUTHERN COLORADO MOUNTAINS TODAY AND INTO THE WEEKEND.
SNOWFALL OF 1 TO 3 FEET WILL BE POSSIBLE OVER THE HIGHER
TERRAIN OF THE SAN JUANS MOUNTAINS. WINTER STORM WARNINGS AND
ADVISORIES ARE IN PLACE.
- THE CHANGES IN THE WEATHER PATTERN WILL BRING MUCH COOLER
TEMPERATURES TO THE REGION ESPECIALLY COMPARED TO THE RECORD
SETTING HEAT OF THE PAST FEW WEEKS.
- HEAVIER MOUNTAIN SNOW WILL SPREAD NORTHWARD INTO THE CENTRAL
AND NORTHERN COLORADO MOUNTAINS SUNDAY INTO EARLY MONDAY AND
COULD BRING ADDITIONAL IMPACTS TO TRAVEL OVER THE HIGHER
PASSES.
- DRYING AND MILD CONDITIONS RETURN TO THE REGION NEXT WEEK AS
HIGH PRESSURE RETURNS.
SHORT TERM /THROUGH SATURDAY/
ISSUED AT 408 AM MDT FRI OCT 18 2024
AS MODELS HAD PREDICTED, A DEEP TROUGH HAS BEEN CARVED OUT OVER
THE GREAT BASIN DURING THE LAST 24 HOURS WITH A CLOSED LOW OVER
EAST-CENTRAL NEVADA. MEANWHILE, THE COLD FRONT ASSOCIATED WITH
THIS SYSTEM RETROGRADED SINCE THURSDAY AFTERNOON AND STRETCHED
SOUTH-SOUTHWEST FROM 40 MILES WEST OF VERNAL TO ST. GEORGE,
UTAH. THICKNESS ANALYSES INDICATED AN AREA OF OVERRUNNING ACROSS
NORTHEAST UTAH AND NORTHWEST COLORADO WHERE MOISTURE SWEEPING
NORTHWARD AHEAD OF THE SYSTEM WAS FEEDING A BROAD SWATCH OF
SHOWERS ACROSS THOSE PORTIONS OF THE FORECAST AREA. MEANWHILE,
THUNDERSTORM ACTIVITY WAS PREVALENT ALONG THE COLD FRONT ITSELF
WHILE MORE SCATTERED ACTIVITY WAS OVER THE WESTERN SAN JUAN'S.
DURING THE DAY TODAY, MODELS TRACK THE LOW SOUTH-SOUTHEAST
ACROSS LAS VEGAS AT 12Z TO NORTHWEST ARIZONA BY MIDDAY, THEN
SOUTHEAST OVER NORTHWEST ARIZONA. IN RESPONSE TO THIS SHIFT,
SHOWERS/THUNDERSTORMS FAVOR EASTERN UTAH, THE WESTERNMOST
PORTIONS OF COLORADO AND THE SAN JUAN MOUNTAINS THIS MORNING.
FAVORABLE OROGRAPHIC LIFT COMBINES WITH DYNAMIC FORCING TO BRING
HEAVY SNOW TO THE EASTERN UINTA, LA SAL, ABAJO AND SAN JUAN
MOUNTAINS THIS MORNING, MAINLY ABOVE 8,000 FEET IN THE NORTH
AND 9,000 FEET IN THE SOUTH. THOUGH LOWER THAN IN THE WESTERN
PORTION OF THE FORECAST AREA, SHOWER/THUNDERSTORM CHANCES
CONTINUE OVER THE REMAINDER OF THE FORECAST AREA. DURING THE
AFTERNOON AS THE VERTICALLY STACKED LOW SHIFTS CLOSER TO THE
FOUR CORNERS DYNAMICS AND OROGRAPHICS BECOME FOCUSED OVER THE
SAN JUAN MOUNTAINS AND SNOW RATES WILL EXPERIENCE AN UPTICK.
SOME THUNDERSNOW IS LIKELY WHICH COULD CREATE NEAR WHITEOUT
CONDITIONS AT TIMES AND EXCESSIVE SNOWFALL RATES. MEANWHILE, THE
COLD FRONT SLOWLY SHIFTS EAST, THEN SOUTH DURING THE DAY. NOT
SURPRISINGLY THEN, TEMPERATURES WILL BE SIGNIFICANTLY COOLER
WITH AFTERNOON HIGHS EXPECTED TO RUN 5 TO 10 DEGREES BELOW
NORMAL.
THE LOW REMAINS QUASI-STATIONARY TONIGHT AND SATURDAY AND AS A
RESULT, THE FOCUS FOR PRECIPITATION SHIFTS TO THE SOUTHERN HALF
OF THE FORECAST AREA. THE SAN JUAN MOUNTAINS AND, TO A LESSER
EXTENT, THE LA SAL AND ABAJO MOUNTAINS WILL BE FAVORED DURING
THIS PERIOD AND SNOW WILL KEEP PILING UP, ESPECIALLY ABOVE THE
9,000 FOOT MARK. NEEDLESS TO SAY OVERNIGHT LOWS WILL ALSO BE
NOTICEABLY COLDER WITH THE HIGHER VALLEYS DIPPING TO NEAR
FREEZING. HIGHS SATURDAY ARE EXPECTED TO BE SIMILAR TO THOSE
FORECAST TODAY. THOUGH MODELS DIALED BACK QPF A BIT FROM
PREVIOUS RUNS, SNOW AMOUNTS ARE STILL EXPECTED TO CONSIDERABLE,
ESPECIALLY FOR THE SAN JUAN MOUNTAINS. CONSEQUENTLY, SAW NO NEED
TO ADJUST CURRENT HIGHLIGHTS.
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
ISSUED AT 408 AM MDT FRI OCT 18 2024
WITH THE SURFACE LOW STRADDLING THE AZ/NM STATE LINE SATURDAY
NIGHT CUT OFF FROM THE POLAR JET, PRECIPITATION WILL BE ON A
SHORT LEASE. PWAT VALUES HANG ON WELL ABOVE NORMAL AROUND THE
CWA, NO DOUBT THANKS TO THE VOLUMES OF SURFACE MOISTURE FROM
FRIDAY AND SATURDAY RAIN AND SNOW SHOWERS. THIS SHOULD BE ENOUGH
TO KEEP SHOWER ACTIVITY GOING TO THE SOUTH OF HIGHWAY 50 INTO
THE OVERNIGHT HOURS. THE CUT OFF LOW DRIFTS NORTH AND SLIGHTLY
EASTWARD INTO SUNDAY MORNING, SPREADING SOME ADDITIONAL
PRECIPITATION UP THE CONTINENTAL DIVIDE DURING THE DAY SUNDAY.
MODEST MOISTURE WILL KEEP SUNDAY SNOWFALLS IN CHECK FOR THE
MOUNTAINS. A FEW ADDITIONAL INCHES FOR THE MOUNTAINS CAN BE
EXPECTED WITH SOME HIGHER PEAKS TAPPING INTO BURSTS OF 6-10
INCHES. WEEKEND TRAVELERS CROSSING PASSES ALONG THE CONTINENTAL
DIVIDE(I.E. VAIL, MONARCH, WOLF CREEK, ETC.)WILL WANT TO WATCH
LOCAL FORECASTS FOR SUNDAY. A PACNW TROUGH PUSHES ASHORE LATE
SUNDAY AND EJECTS THE LOW NORTHEAST ONTO THE PLAINS. A WEAK
TRANSITORY RIDGE BUILDS IN MONDAY AND BRINGS TEMPERATURES BACK
TOWARDS NEAR NORMAL OCTOBER CLIMATOLOGY AND LIKELY SOME
SUNSHINE. THIS BEGINS A WEEK LONG WARM UP FOR THE REGION IN THE
WAKE OF THE WEEKEND STORM. TEMPERATURES WILL CLIMB INTO THE 70'S
FOR LOW VALLEYS AND 50'S/60'S FOR THE MOUNTAINS BY THURSDAY
AFTERNOON. THIS ALL ARRIVES UNDER ANOTHER FLATTENED RIDGE DRAPED
ACROSS THE SOUTHERN U.S. AND THE POLAR JET STILL PARKED ACROSS
THE CANADIAN BORDER. HIGH PRESSURE OFF THE BAJA PENINSULA HOLDS
STEADY AND KEEPS PUSHING THE WAVE TRAIN NORTHWARD. SPAGHETTI
PLOTS CONTINUE TO ALIGN WITH THIS SOLUTION INTO FRIDAY.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1138 AM MDT FRI OCT 18 2024
GUSTY WINDS PERSIST ACROSS THE AREA THIS AFTERNOON, ALONG WITH
WIDESPREAD SHOWERS AND EVEN SOME THUNDERSTORMS. HIGHER
ELEVATIONS HAVE SEEN A SWITCHOVER TO ALL SNOW OR A RAIN/SNOW
MIX, INCLUDING KTEX. THIS TREND WILL CONTINUE THROUGH THE
EVENING HOURS. SOME SNOW MAY MIX IN AT KDRO DURING THE EARLY
MORNING HOURS TOMORROW AS THE HEAVIEST PRECIPITATION MOVES IN.
VFR CONDITIONS WILL MIX WITH MVFR TO IFR CONDITIONS THROUGH THE
NEXT 24 HOURS. MOUNTAIN OBSCURATION IS EXPECTED, ESPECIALLY IN
THE SAN JUANS. WINDS WILL GRADUALLY WEAKEN AND BECOME EITHER
LIGHT AND VARIABLE OR LIGHT AND TERRAIN DRIVEN OVERNIGHT
TONIGHT. CEILINGS WILL REMAIN NEAR OR BELOW ILS BREAKPOINTS AT
KASE, KEGE, AND KRIL THROUGH THE PERIOD. IMPROVING CONDITIONS
ARE EXPECTED NORTH OF I-70 TOMORROW AFTERNOON.
GJT WATCHES/WARNINGS/ADVISORIES
CO...WINTER STORM WARNING UNTIL NOON MDT SUNDAY FOR COZ018-019.
UT...WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR UTZ023.
WINTER WEATHER ADVISORY UNTIL 9 AM MDT SATURDAY FOR UTZ028.
SHORT TERM...NL
LONG TERM...LTB
AVIATION...TGJT
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