066
FXUS65 KGJT 191803
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1203 PM MDT SAT OCT 19 2024
KEY MESSAGES
- A STRONG CLOSED LOW PRESSURE SYSTEM OVER NORTH-CENTRAL ARIZONA
WILL REMAIN OVER ARIZONA THROUGH THE DAY TODAY BEFORE LIFTING
NORTH ACROSS THE AREA SUNDAY. THIS KEEPS HEAVIEST
PRECIPITATION CONCENTRATED OVER SOUTHWEST COLORADO AND WILL
ALSO BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT. THIS INCLUDES
AREAS OF HEAVY SNOWFALL OVER THE SAN JUAN MOUNTAINS WHERE
TRAVEL IMPACTS CAN BE EXPECTED.
- THE CHANGES IN THE WEATHER PATTERN HAS BROUGHT MUCH COOLER
TEMPERATURES TO THE REGION ESPECIALLY COMPARED TO THE RECORD
SETTING HEAT OF THE PAST FEW WEEKS...AND THIS WILL PERSIST
THROUGH THE WEEKEND BEFORE WARMING RETURNS NEXT WEEK.
- PRECIPITATION 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.
UPDATE
ISSUED AT 822 AM MDT SAT OCT 19 2024
THE ADVISORY FOR THE SOUTHEAST UTAH MOUNTAINS HAS BEEN ENDED
THIS MORNING AS SNOTELS HAVE FLAT-LINED. AND ADDITIONAL 1 T 4
INCHES COULD FALL OVER THE NEXT 24 HOURS OVER THE HIGHEST
ELEVATIONS HERE BUT OVERALL THE THREAT OF SIGNIFICANT AND
WIDESPREAD HEAVY SNOW HAS ENDED. THERE WILL BE NOTICEABLE LULL
IN WIDESPREAD IMPACTS AT LEAST THROUGH THIS MORNING AND LIKELY
INTO THE EARLY AFTERNOON BEFORE CONVECTION BEGINS TO ADD IT'S
MAGIC. TO BE HONEST WOULD LIKE A DO-OVER WITH THIS STORM AS
SNOW LEVELS HAVE REMAINED QUITE HIGH AND PROBABLY MY FIRST
MISTAKE WAS TO LOWER THE WARNING ELEVATIONS TO 8500 FEET WHERE
IMPACTS HAVE BEEN ALMOST NON-EXISTENT. WE HAVE HAD SOME SNOW
OVER THE PASSES FOR IMPACTS AND HIGH SNOTELS ARE IN THE 8 TO 16
INCH RANGE SO IT DID SNOW. WATER VAPOR SHOWS THE LOW HAS
DRIFTING A BIT FARTHER SOUTH INTO AZ WHERE A STRONGER PV LOBE
IS NOW ROUNDING THE BASE OF THE CIRCULATION. THIS WILL NOT
ROTATE UP TOWARD THE 4 CORNERS UNTIL LATER THIS AFTERNOON...BUT
WILL BE THE FOCUS FOR THE NEXT BIGGER PUSH OF ASCENT AND SPREAD
MORE SIGNIFICANT PRECIPITATION OVER THE THE SOUTHERN CWA. AS
THIS LOBE OF PV ROLLS THROUGH IT GIVE THIS A STORM A PUSH OUT OF
THE AREA WHICH WILL THEN SPREAD SNOW ACROSS THE AREA AGAIN
INCLUDING THE CENTRAL MOUNTAINS THROUGH LATE TOMORROW. SO
WARNINGS LIKELY TO STAY IN PLACE FOR NOW SINCE IT THE FIRST BIG
STORM OF THE SEASON THOUGH ELEVATIONS BELOW 9000 FEET MAY NOT
SEE MUCH MORE SNOW. WILL HAVE TO CHALK THIS UP TO ANOTHER
LEARNING EXPERIENCE IN THE WORLD OF METEOROLOGY.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 335 AM MDT SAT OCT 19 2024
SATELLITE IMAGERY SHOWS THE CLOSED LOW SPINNING OVER NORTH-
CENTRAL ARIZONA AT THIS EARLY SATURDAY MORNING HOUR WITH STRONG
ENHANCEMENT OCCURRING ON THE EASTERN AND NORTHEAST SIDES OF THE
LOW ACROSS THE SOUTHERN SAN JUAN MOUNTAINS. THIS IS VERY EVIDENT
WHEN LOOKING AT SNOTELS THAT NOW INDICATE OUR STORM TOTAL
SNOWFALL IS UP TO 9 TO 18 INCHES, WITH HEAVY SNOWFALL RATES
PICKING UP LAST EVENING AND DURING THIS CURRENT OVERNIGHT
PERIOD. WEBCAMS SHOW SNOW FALLING AND ACCUMULATING ON THE ROAD
SURFACES ACROSS THE HIGHER ELEVATIONS OF THE SAN JUANS ALONG
HIGHWAY 160 AND 550. THIS WILL CONTINUE TO BE THE FAVORED AREA
OF SIGNIFICANT SNOWFALL ACCUMULATIONS, SO WINTER STORM WARNINGS
REMAIN ON TRACK OVER THE SAN JUAN MOUNTAINS THROUGH NOON SUNDAY.
THE LA SALS, WHERE A WINTER WEATHER ADVISORY REMAINS IN EFFECT
UNTIL 9 AM THIS MORNING, HAS ALREADY PICKED UP AROUND 7 INCHES
WITH SOME SHOWER ACTIVITY STILL WRAPPING AROUND THE LOW, BUT
RATES HAVE LESSENED ACROSS SOUTHEAST UTAH MOUNTAINS THAT THE
CURRENT WINTER WEATHER ADVISORY SEEMS FINE AT THE MOMENT, SO
WILL LET IT CONTINUE FOR NOW AS ADDITIONAL SNOW LOOKS TO
ACCUMULATE THROUGH THE EARLY MORNING. THE REST OF THE CENTRAL
AND NORTHERN MOUNTAINS HAVEN'T REALLY SEEN MUCH IN THE WAY OF
SNOWFALL AS TEMPERATURES HAVE REMAINED TOO WARM THAT FAR NORTH
AWAY FROM THE LOW. SINCE THIS LOW IS CLOSED OFF AND CONCENTRATED
OVER NORTHERN ARIZONA, THE SOUTHERN MOUNTAINS HAVE BEEN THE
PRIMARY BENEFICIARIES AS THEY ARE AT THE FOREFRONT OF THE BEST
DYNAMIC FORCING AND WILL CONTINUE TO BE THROUGHOUT THE DAY
TODAY. CAPE IS IN THE 200 TO 400 J/KG RANGE ACROSS SOUTHWEST
COLORADO SO THUNDERSTORMS ARE ALSO POSSIBLE WHICH WOULD HELP
BRING SNOW LEVELS DOWN AT TIMES AND RESULT IN HEAVIER RATES.
SOME SHEAR EXISTS AS WELL IN CLOSER PROXIMITY TO THE LOW SO SOME
STORMS IN THE LOWER SOUTHERN ELEVATIONS COULD PRODUCE SOME SMALL
HAIL AS WELL. IN FACT, MODELS ARE INDICATING THAT THIS CLOSED
LOW CENTER WILL DRIFT FURTHER SOUTH INTO CENTRAL ARIZONA TODAY,
WHICH FURTHER LESSENS POTENTIAL ACROSS THE CENTRAL AND NORTHERN
MOUNTAINS AND KEEPS SNOWFALL CONCENTRATED AMONG THE SAN JUANS,
ESPECIALLY THE SOUTHERN SAN JUANS. HENCE, THE PRECIPITATION
AMOUNTS NORTH OF THE SAN JUANS CAME DOWN A BIT AND TEMPERATURES
TODAY CAME UP A BIT HIGHER THAN PREVIOUSLY FORECAST.
BY SUNDAY, THE CLOSED LOW FINALLY MOVES TOWARDS THE FOUR CORNERS
AND LIFTS NORTHWARD ACROSS SOUTHWEST TO CENTRAL COLORADO SUNDAY
AFTERNOON, ARRIVING OVER CENTRAL COLORADO ON THE FRONT RANGE BY
MONDAY MORNING. LOTS OF DYNAMIC FORCING AND FAVORED UPSLOPE
WEAKENS AS THIS LOW LIFTS ACROSS THE AREA, BUT SUNDAY APPEARS TO
DRAW MORE SCATTERED TO WIDESPREAD SHOWERS ACROSS THE AREA WITH
THE CENTRAL AND SOUTHERN MOUNTAINS SEEING SOME SNOWFALL
ACCUMULATION IN THE REALM OF 2 TO 4 INCHES AT BEST. THE CENTRAL
COLORADO MOUNTAINS AND PASSES ALONG I-70 AND THE CENTRAL DIVIDE
COULD SEE SOME IMPACTS TO THE COMMUTE BUT SNOWFALL TOTALS AND
RATES APPEAR ON THE LOWER SIDE. NOT ANTICIPATING ENOUGH
ADDITIONAL ACCUMULATION SUNDAY TO WARRANT ANY EXPANSION OR
EXTENSION OF THE CURRENT WINTER WEATHER HIGHLIGHTS AT THIS TIME.
AS FAR AS TEMPERATURES ARE CONCERNED, HIGHS WILL BE MILDER TODAY
THAN YESTERDAY ACROSS THE NORTHERN AND CENTRAL AREAS WITH COOLER
HIGHS ACROSS THE SOUTH WHERE MORE CLOUDS AND SHOWERS WILL
PERSIST. TEMPERATURES THAN COOL DOWN SUNDAY AS THE LOW PASSES
OVERHEAD AND MORE CLOUDS AND SHOWERS ARE EXPECTED. HIGHS WILL
STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. AS FAR AS OVERNIGHT
LOWS, THERE WAS SOME CONCERN A FEW DAYS AGO ABOUT POTENTIAL
FREEZE BUT THE LATEST GUIDANCE AGAIN HAS LOWS A BIT MILDER THAN
PREVIOUSLY THOUGHT AND KEEPING LOWS ABOVE FREEZING WITH NEAR
FREEZING MORE LOCALIZED ACROSS THE NORTHERN VALLEYS AND NOT AS
WIDESPREAD TO WARRANT ANY FREEZE HIGHLIGHTS.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
ISSUED AT 335 AM MDT SAT OCT 19 2024
THE CLOSED LOW WILL CONTINUE TO FILL AND LIFT NORTHEASTWARD AND
BY SUNDAY NIGHT THE CENTER WILL BE MOVING ALONG THE CO/NM
BORDER, GIVING ONE LAST HURRAH OF PRECIP OVER THE SAN JUANS AND
ALONG THE DIVIDE. IN A SHORT 6 HOURS, THE LOW CENTER WILL HAVE
ALREADY MOVED TO JUST WEST OF COLORADO SPRINGS AND BY DAYBREAK
WILL BE JUST WEST OF THE CO/KS BORDER. ALL THAT BEING SAID, LOOK
FOR CLEARING CONDITIONS FROM WEST TO EAST ON MONDAY THOUGH
EASTERN UTAH WILL PROBABLY ONLY HAVE A FEW CLOUDS TO SPEAK OF.
BY NOON, PLENTY OF SUNSHINE IS EXPECTED ACROSS THE CWA EXCEPT
THE CENTRAL AND NORTHERN MOUNTAINS BUT BY LATE AFTERNOON, SUNNY
SKIES WILL MAKE AN APPEARANCE THERE AS WELL. MOST AREAS WILL SEE
SEASONAL HIGH TEMPS AND IF NOT, MAYBE A FEW DEGREES ABOVE BUT
NOTHING LIKE WE SAW BEFORE THE STORM MOVED IN.
SYNOPTICALLY SPEAKING, A RIDGE OF HIGH PRESSURE WILL BUILD IN
MONDAY BUT IT WON'T LAST LONG AS THE POLAR FRONT TO OUR NORTH
BREAKS THE RIDGE DOWN. ONCE THIS OCCURS, ZONAL FLOW WILL SETUP
ACROSS THE CWA. THIS FLOW WILL REMAIN TUESDAY AND WEDNESDAY
UNTIL HIGH PRESSURE STARTS BUILDING IN FROM THE SOUTHWEST. THE
END RESULT, AS YOU MIGHT HAVE GUESSED, IS TEMPERATURES CLIMBING
AND REACHING 5 TO 10 DEGREES ABOVE NORMAL FROM ABOUT TUESDAY
ONWARDS.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1147 AM MDT SAT OCT 19 2024
SHOWERS CONTINUE WITH SNOW ABOVE ABOUT 9000 FT ACROSS SOUTHWEST
COLORADO AND SOUTHEAST UTAH TODAY AS THE STORM SYSTEM REMAINS
OVER ARIZONA. MOUNTAIN TERMINALS LIKE KTEX AD WELL AS ADJACENT
SOUTHERN VALLEYS LIKE KDRO WILL SEE BELOW BREAKPOINT CONDITIONS
THROUGHOUT THE NEXT 24 HOURS WITH LOWER CIGS AND VSBY IN
SHOWERS. NORTH OF THE SAN JUANS, THERE ARE MOSTLY MID LEVEL
CLOUDS WITH VFR CONDITIONS, THE EXCEPTION BEING KHDN WHERE A LOW
DECK HANGS IN THE VALLEY WITH CEILINGS BELOW BREAKPOINTS. EXPECT
THESE KHDN CEILINGS TO LIFT THROUGH THE AFTERNOON. CLOUDS AND
SHOWERS INCREASE OVERNIGHT INTO SUNDAY MORNING, SPREADING
NORTH AS THE STORM SYSTEM FINALLY MOVES NORTHEAST TOWARDS THE
FOUR CORNERS AND EVENTUALLY TRACKS ACROSS WESTERN COLORADO
DURING THE DAY ON SUNDAY.
GJT WATCHES/WARNINGS/ADVISORIES
CO...WINTER STORM WARNING UNTIL NOON MDT SUNDAY FOR COZ018-019.
UT...NONE.
UPDATE...15
SHORT TERM...MDA
LONG TERM...TGR
AVIATION...TGJT
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