885
FXUS65 KGJT 310608
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1208 AM MDT SAT MAY 31 2025
KEY MESSAGES
- TEMPERATURES CONTINUE WELL ABOVE NORMAL TOMORROW AND SUNDAY,
BEFORE COOLING EARLY NEXT WEEK.
- AFTERNOON SHOWERS AND THUNDERSTORMS CONTINUE ON THE TERRAIN
SATURDAY AND SUNDAY, WITH SOME PRODUCING GUSTY WINDS AND SHORT
DOWNPOURS.
- AN EXCESS OF MOISTURE IS EXPECTED TO ARRIVE MONDAY AND PRODUCE
WIDESPREAD RAINSHOWERS AND THUNDERSTORMS. LOCALIZED FLOODING
REMAINS A CONCERN NEXT WEEK, GIVEN SOME OF THE FORECAST
VALUES FOR AVAILABLE MOISTURE.
SHORT TERM /THROUGH SATURDAY/
ISSUED AT 242 PM MDT FRI MAY 30 2025
MOISTURE TRAPPED BENEATH THE RIDGE OF HIGH PRESSURE ARCED ACROSS THE
ROCKIES IS PRODUCING A WELL DEFINED CUMULUS FIELD ON AREA TERRAIN
FEATURES. VALLEYS AND LOW ELEVATION DESERTS REMAIN BAKED UNDER
GENEROUS SUNSHINE WITH HIGHS HEADED 10 DEGREES IN EXCESS OF CLIMATE
NORMALS. SOME OF THIS SUN COULD GET MUTED BY CLOUD COVER AND/OR
SHOWER DEVELOPMENT. THUS FAR TODAY, SHOWER ACTIVITY IS MUTED IN
COMPARISON TO YESTERDAY. A FEW THUNDERSTORMS HAVE SPARKED SOUTH OF
THE WY BORDER ALONG THE PARK RANGE. STORM TRACKS ARE NORTH TO SOUTH
THIS AFTERNOON. SATELLITE IMAGERY SHOWS A FEW SHOWERS BEGINNING TO
CONGREGATE ON THE CENTRAL MOUNTAINS. THIS WILL CONTINUE UNTIL NEAR
SUNSET WHEN AFTERNOON INSTABILITY FINALLY TAPERS OFF. SHOWERS WILL
BE SHORT LIVED AFFAIRS, WITH A FEW CAPABLE OF PRODUCING LIGHTNING
OVER THE NEXT FEW HOURS. I WOULD EXPECT A FEW SHORT DOWNPOURS AND
SOME GUSTY WINDS, BUT NOTHING EXTRAORDINARY.
CLOUDS WILL DISSIPATE THIS EVENING AND QUIET OVERNIGHT CONDITIONS
WILL KICK OFF THE WEEKEND TONIGHT. HIGH PRESSURE HANGS ON SATURDAY
FOR ANOTHER DAY. TEMPERATURES WILL CONTINUE TO INCH UPWARD AGAIN
UNDER LIGHT WINDS, WITH HIGHS 10 TO 15 DEGREES ABOVE NORMAL IN THE
AFTERNOON. TERRAIN BASED SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN.
MODELS ARE SUGGESTING A SLIGHT INCREASE IN AVAILABLE MOISTURE
SATURDAY AFTERNOON, LIKELY SOME INFLUENCE OF THE BAJA STORM
DISCUSSED BELOW. UPPER LEVEL FLOW HOLDS ON TO A GENERAL
NORTHERLY TRAJECTORY SATURDAY. THIS LIKELY SETS UP A REGIME
SIMILAR TO TODAY. CONFIDENCE IN STORM COVERAGE IS LOW AND WILL
LIKELY DEPEND ON SMALL SCALE FEATURES OUTSIDE OF MODEL GUIDANCE.
HI RES MODELS ARE SHOWING SHOWERS INITIATING SOMETIME AROUND
1300 MDT AND TAPERING TOWARDS SUNSET AGAIN, WITH SOME BIAS
TOWARDS THE SAN JUANS AND UP AGAINST THE CONTINENTAL DIVIDE.
QUIET CONDITIONS WILL RETURN AGAIN SATURDAY NIGHT.
LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/
ISSUED AT 242 PM MDT FRI MAY 30 2025
SUNDAY WILL BE THE WARMEST DAY OF THE PERIOD AND MOST LIKELY THE
WARMEST OF THE SEASON THUS FAR. DESERT VALLEYS WILL GET INTO THE 90S
AND PUSH 100 IN SPOTS , WHILE MOUNTAIN TOWNS GET INTO THE 70S AND
SOME THE 80S. THERE MAY BE ENOUGH MOISTURE FOR HIGH TERRAIN SHOWERS
AND STORMS MAINLY IN THE AFTERNOON. THEY WILL PRODUCE MORE WIND THAN
RAINFALL. ATTENTION THEN TURNS TO A CLOSED LOW PRESSURE OFF THE
COAST OF THE BAJA PENINSULA. ON SUNDAY IT WILL BEGIN TO LIFT
NORTHEASTWARD, WHICH SENDS IT ON A TRACK FOR OUR AREA. BEFORE
THAT HAPPENS IT WILL PICK UP MOISTURE FROM THE REMNANTS OF
TROPICAL STORM ALVIN IN THE EASTERN PACIFIC. ON MONDAY, THIS
SURGE OF MOISTURE ARRIVES ALONG WITH THE LOW PRESSURE THAT WILL
BE WEAKENING INTO AN OPEN SHORTWAVE TROUGH. NONETHELESS IT WILL
PROVIDE LARGE-SCALE LIFT THAT IN COMBINATION WITH THIS MOISTURE
WILL RESULT IN SCATTERED TO WIDESPREAD SHOWERS AND STORMS. THE
PWATS AT THIS TIME REACH 200-300 PERCENT OF NORMAL, WHICH IS
HIGHLY ANAMOLOUS. ONE OF THE MAIN UNCERTAINTIES IS THE TIMING OF
MOISTURE AND OR CLOUDS ON MONDAY. ANY LOCATIONS THAT ARE ABLE
TO GET SOME SUN WILL BE ABLE TO BUILD INSTABILITY. IF THE
INSTABILITY MATERIALIZES THEN THE CONVECTION THAT FORMS IN THE
AFTERNOON COULD BE CAPABLE OF PRODUCING HEAVY RAINFALL, HAIL AND
STRONG WINDS. THE OTHER SCENARIO IS MORE STRATIFORM WITH
EMBEDDED CONVECTION, WHICH WOULD MOST LIKELY PRODUCE MORE LIGHT
TO MODERATE RAINFALL.
THE OTHER COMPLICATED FACTOR WITH THIS TIME FRAME IS AN ACTIVE
NORTHERN STREAM, WHICH COULD SEND A FRONTAL BOUNDARY DOWN FROM THE
NORTH INTO THE MOIST AIRMASS ON TUESDAY AND WEDNESDAY. THIS WOULD BE
ANOTHER MECHANISM FOR FORCING SHOWERS AND STORMS. AT THAT SAME TIME
A SECOND LOW PRESSURE WORKS IT'S WAY INTO SOUTHERN CALIFORNIA
AND THE DESERT SOUTHWEST. THIS SYSTEM COULD ALSO INTERACT WITH
THE MOISTURE AS WELL AND CAUSE ADDITIONAL ROUNDS OF
PRECIPITATION. THAT SYSTEM IS CERTAINLY TOO FAR OUT TO GET INTO
THE DETAILS, BUT SOMETHING TO WATCH. IF THE SUN CAN DESTABILIZE
THE ATMOSPHERE ON TUESDAY AND WEDNESDAY THEN WE COULD BE LOOKING
AT THE POTENTIAL FOR HEAVY RAINFALL. MODEL CONSENSUS IS SHOWING
PROBABILITIES OVER 50% FOR THE CHANCE OF GETTING OVER AN INCH
OF LIQUID DURING THE 3-DAY PERIOD. PROBABILITIES REACH 30% FOR
OVER 2 INCHES IN THE SAN JUANS AND PARK RANGE. THIS COULD CHANGE
AND UNCERTAINLY IS HIGHER IF CONVECTION IS THE FAVORED MODE.
WITH ALL OF THE RAIN AND CLOUDS AROUND ON MONDAY THROUGH
WEDNESDAY TEMPERATURES GO WELL BELOW NORMAL.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1142 PM MDT FRI MAY 30 2025
EXPECT VFR CONDITIONS WITH MOSTLY CLEAR SKIES AND LIGHT TERRAIN
DRIVEN WINDS THROUGH THE TAF PERIOD. ISOLATED SHOWERS AND
THUNDERSTORMS WILL DEVELOP BETWEEN ABOUT 19Z AND 01Z OVER THE
HIGHER TERRAIN ALONG THE COLORADO DIVIDE.
GJT WATCHES/WARNINGS/ADVISORIES
CO...NONE.
UT...NONE.
SHORT TERM...LTB
LONG TERM...KJS
AVIATION...DB
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