Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 302243
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
443 PM MDT TUE JUN 30 2015

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 328 PM MDT TUE JUN 30 2015

FIRST THUNDERSTORMS OF THE AFTERNOON OCCURRED IN NE UTAH WHERE
DEEPER MOISTURE WAS ADVECTING IN FROM THE WEST. THIS MOISTURE
ADVECTION CONTINUES ACROSS NE UTAH AND NW CO THIS LATE AFTERNOON
AND EVENING. STORMS ACROSS THE NORTH WILL BE CAPABLE OF PRODUCING
STRONG OUTFLOW WINDS AND SMALL HAIL THIS AFTERNOON. SCATTERED
NORTHERN STORMS ARE PERSIST BEYOND SUNSET THEN ISOLATED SHOWERS
THERE OVERNIGHT. ELSEWHERE STORMS WILL END WITH SUNSET.
TEMPERATURES REMAIN ABOVE NORMAL OVERNIGHT.

HIGH PRESSURE WILL RETROGRADE OVER NEVADA ON WEDNESDAY...ALLOWING
FOR A TRAILING SHORT WAVE TO DRAG ACROSS NW COLORADO LATE IN THE
DAY. THIS BOOSTS DIURNALLY DRIVEN CONVECTION AND ALLOW FOR SOME
STORMS TO MIGRATE OFF THE HIGHER TERRAIN AND IMPACT VALLEY
AREAS...AT LEAST FOR A 1-3 HOUR PERIOD LATE IN THE DAY. WITH THE
SHORT MOVING DOWNSTREAM BY NIGHTFALL...STORMS SHOULD BE ENDING
BY LATE EVENING.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 328 PM MDT TUE JUN 30 2015

THURSDAY AND FRIDAY...DRIER AIR SPREADS INTO THE FORECAST AREA
FROM THE NW AND LOWERS CONVECTIVE POTENTIAL. THE ONLY AREA THAT
MIGHT OBSERVE A LATE DAY STORM WILL BE THE COLORADO HIGH
COUNTRY...OR TOWARD THE COLORADO SPINE AND THE SAN JUAN MOUNTAINS
AND NEARBY FOOTHILLS. SIMILAR CONDITIONS ON FRIDAY...HOWEVER THE
AIR MASS WILL NOT BE QUITE AS DRY AND ISOLATED MOUNTAIN STORMS
SHOULD OCCUR FARTHER WEST.

SATURDAY THROUGH TUESDAY...PATTERN CHANGE OCCURS AS HIGH PRESSURE
ALOFT SHIFTS FROM COLORADO ON SATURDAY TO THE SRN PLAINS BY NEXT
TUESDAY. MONSOONAL MOISTURE SURGE GETS GOING ON SUNDAY AND CONTINUES
INTO TUESDAY. SUNDAY MAY BE THE BEST DAY FOR THUNDERSTORM COVERAGE
AS A PASSING SHORT WAVE TO OUR NORTH ALLOWS FOR BETTER MOISTURE
TRANSPORT. THE GFS SHOW PRECIPITABLE WATER EXCEEDING ONE INCH OVER
THE ERN UTAH DESERTS. HOWEVER THE ECMWF SHOW SOME DIFFERENCES IN
TERMS OF THE STRENGTH OF THIS MONSOONAL SURGE. GIVEN A BLEND OF
SOLUTIONS...THE FORECAST FOR DAYS 5 THROUGH 7 TENDS TO BE MORE
BROADBRUSH. EITHER WAY THE MEDIUM RANGE MODELS INDICATE THAT THE
"MONSOON" SEASON ARRIVES IN EARNEST NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 443 PM MDT TUE JUN 30 2015

AFTERNOON INSTABILITY IS ALLOWING FOR SCATTERED TO ISOLATED
THUNDERSTORM COVERAGE ACROSS NORTHWEST COLORADO AND NORTHEAST
UTAH. THE KVEL...KEGE...AND KASE TERMINAL HAVE THE BEST CHANCES OF
BEING IMPACTED BY THIS WEATHER THROUGH 01/04Z. WIND GUSTS TO 40
MPH WILL THE MAIN IMPACTS AS RAINFALL RATES MAY NOT BE ENOUGH TO
REDUCE VSBYS TO MVFR LEVELS. THEREFORE VFR CONDITIONS ARE EXPECTED
TO PREVAIL OVER THE NEXT 24 HOURS. MOISTURE INCREASES ACROSS THE
REGION ON WEDNESDAY WHICH SHOULD LEAD TO A NOTICEABLE INCREASE IN
THUNDERSTORM COVERAGE DURING THE AFTERNOON HOURS.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&

$$

SHORT TERM...JOE/PF
LONG TERM...PF
AVIATION...TGJT



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