021
FXUS65 KGJT 280529
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1029 PM MST SAT FEB 27 2021
SHORT TERM
(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 254 PM MST SAT FEB 27 2021
THE FIRST MAIN WAVE HAS PUSHED THROUGH WITH VARIED SUCCESS AND IN
SOME PLACES EXCEEDED EXPECTATIONS. THE TRAILING WAVE IN THE TROUGH
IS NOW DIGGING DOWN THROUGH THE HEART OF THE GREAT BASIN TOWARD
THE 4 CORNERS. THE PERSISTENT WSW FLOW ON THE LEADING EDGE AND
UNSTABLE CONDITIONS ALOFT HAVE PRODUCED A PERFECT SET UP FOR A
FROUDE-BASED BAND OF SNOW TO STAY ANCHORED OFF THE BACK OF THE
GRAND MESA OVER THE UPPER ROARING FORK VALLEY. THIS WAS IN
VICINITY OF THE SNOWMASS WHERE AT LEAST 8 INCHES HAS FALLEN WITH
MUCH LESS JUST TO THE SOUTH LOOKING AT AREA SNOW GAUGES. THIS
CONVECTION ALSO HELPED THE PARK RANGE SEE SOME AREAS OF 12+ INCHES
OF SNOW. THIS CONVECTION ALSO MEANT MANY AREAS IN THE SAME ZONES
RECEIVED MUCH LESS...SO BOOM OR BUST. THE TROUGH WILL CONTINUE A
SLOW SOUTHERLY DRIFT ACROSS THE CWA TONIGHT AS IT ELONGATES DUE TO
THE ENERGY CLOSING OFF A LOW TO OUR SW. THE COLD AIR AND JET
ALOFT IS LIKELY TO KEEP ISOLATED TO SCATTERED SHOWERS OVER THE
COLORADO HIGH COUNTRY UNDER THE CORE OF THE TROUGH. EXPECTED
IMPACTS ARE MINIMAL THOUGH SOME TRAVEL ISSUES CONTINUE. THE TROUGH
SWINGS ACROSS THE FAR SE PORTION OF THE CWA ON SUNDAY AND THIS IS
WHEN THE SOUTHERN MOUNTAINS SHOULD SEE THE BETTER COVERAGE OF
SNOW SHOWERS. THERE IS NO MOISTURE ADVECTING INTO THIS SYSTEM ON
THIS SIDE OF THE HILLS SO SNOW AMOUNTS OVERALL LOOK NON-IMPACTFUL.
VERY DRY IS FILTERING IN AS WELL WITH DEW POINTS AT GJT -12F FOR
A HUMIDITY LEVEL OF 11 PERCENT THIS AFTERNOON. THERE ARE A LOT OF
RETURNS ON THE RADAR UNDER THE COLD POOL ALOFT BUT THE FARTHER
WEST IN THE CWA THE LESS LIKELY SNOW WILL HIT THE GROUND. THIS DRY
AIR WILL LEAD TO MUCH COLDER TEMPERATURES TONIGHT AS CLEARING
BEGINS IN MANY AREAS. THIS REMAINS TRUE FOR SUNDAY NIGHT AND SOME
OF THE HIGH BASINS MAY SEE DOUBLE DIGIT READINGS BELOW ZERO. THE
WARMUP WILL NOT BEGIN UNTIL THE START OF THE WEEK...BUT WILL BE
QUITE REMARKABLE.
LONG TERM
(MONDAY THROUGH SATURDAY)
ISSUED AT 254 PM MST SAT FEB 27 2021
A TRANSITORY RIDGE CENTERED OVER THE INTERMOUNTAIN WEST WILL SLIDE
SLOWLY EASTWARD ON MONDAY. BY TUESDAY, FLOW BECOMES SOUTHWEST AHEAD
OF A MID-LEVEL LOW OFF THE COAST OF CALIFORNIA. MODELS PROG THIS
LOW PRETTY MUCH STRAIGHT EASTWARD NEAR THE SOUTHERN CONUS BORDER;
PASSING JUST TO THE SOUTH OF US ON THURSDAY. WHILE THIS SYSTEM
LOOKS TO BE QUITE POTENT, IT'LL BE FAIRLY QUICK MOVING WITH ONLY
AROUND 24 HOURS OF DYNAMIC LIFT FAVORING THE SOUTHERN 1/3 OF THE
FORECAST AREA. HAVE KEPT NBM POPS WHICH DICTATE SLIGHT/CHANCE
PRECIPITATION OVER THE SOUTHERN MOUNTAINS AND SURROUNDING VALLEYS.
QPF AMOUNTS LOOK TO BE AROUND 1/4 INCH WITH A COUPLE PEAKS NEAR 1/2
INCH. ALTHOUGH MODELS HAVE BEEN CONSISTENT WITH THE LATITUDE OF
THIS SYSTEM, A SLIGHT NORTH/SOUTH DEVIATION COULD SIGNIFICANTLY
ALTER THE STORM QPF. IN IT'S WAKE, A RIDGE QUICKLY BUILDS OVER THE
INTERMOUNTAIN WEST...WHICH THEN INTENSIFIES ON FRIDAY. ALTHOUGH
MODELS AGREE THAT A TROUGH WILL SIT OFF THE WEST CONUS COAST,
QUITE A BIT OF DISAGREEMENT REMAINS AS TO HOW THIS SYSTEM
INTERACTS WITH OUR HIGH-AMPLITUDE RIDGE GOING INTO NEXT WEEKEND.
TEMPERATURES WILL START OUT AROUND 5 DEGREES BELOW NORMAL ON MONDAY
AND MONDAY NIGHT. SOUTHWEST FLOW THEN KICKS IN AGAIN WARMING THINGS
UP TO NEAR NORMALS FOR TUESDAY / WEDNESDAY. THE AFORMENTIONED LARGE
RIDGE WILL BUILD TEMPERATURES 5-10 DEGREES ABOVE NORMAL BY FRIDAY /
SATURDAY...WHICH IS AROUND 25 DEGREES HIGHER THAN TODAY.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1027 PM MST SAT FEB 27 2021
ALL TERMINALS HAVE COME UP TO VFR CONDITIONS AND ARE EXPECTED TO
REMAIN SO FOR THE NEXT 24 HOURS. HOWEVER, WITH MIDLEVEL CLOUDS
STILL EXPECTED TO REMAIN THROUGH THE OVERNIGHT HOURS, MOUNTAIN TAF
SITES WILL OCCASIONALLY DROP BELOW ILS BREAKPOINTS THROUGH
TOMORROW MORNING. WINDS WILL PICK UP DURING THE MORNING HOURS, BUT
ARE NOT EXPECTED TO BE GUSTY.
GJT WATCHES/WARNINGS/ADVISORIES
CO...NONE.
UT...NONE.
SHORT TERM...15
LONG TERM...SS
AVIATION...BGB
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