Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 031646
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1046 AM MDT SUN MAY 3 2015

.UPDATE...
ISSUED AT 1037 AM MDT SUN MAY 3 2015

UPLIFT FROM THE SHORTWAVE TROUGH OVER SW CO AND SE UT IS
ENHANCING CONVECTION OVER THE FOUR CORNERS AREA...THE SAN JUAN
MOUNTAINS AND THE ABAJOS. A BAND OF SCATTERED SHOWERS AND ISOLD
THUNDERSTORMS ASSOCIATED WITH THE PVA REGION WILL PROGRESS NE AND
OVER THE SAN JUANS BY EARLY THIS AFTERNOON...THEN CONTINUE MOVING
NE THROUGHOUT THE AFTERNOON. HAVE BOOSTED AREAL COVERAGE OF
SHOWERS AND THUNDERSTORMS IN THESE AREAS TODAY.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 400 AM MDT SUN MAY 3 2015

AN UPPER DISTURBANCE WILL BE CARRIED BY THE SOUTH/SOUTHWEST ACROSS
THE AREA FROM SOUTHWEST TO NORTHEAST TODAY. THE FLOW...ALBEIT
WEAK...WILL ALSO KEEP A MODEST AMOUNT OF MOISTURE STREAMING INTO
THE REGION. THESE TWO INGREDIENTS ALONG WITH DAYTIME HEATING WILL
RESULT IN AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY THIS
AFTERNOON.

IN THE BIGGER PICTURE...THE NEXT SOUTHERN LOW PRESSURE SYSTEM WILL
APPROACH THE SOUTHERN CA COAST THIS AFTERNOON...THEN MOVE INTO THE
DESERT SOUTHWEST ON MONDAY. AHEAD OF THIS LOW...BETTER MOISTURE AND
INSTABILITY WILL MOVE INTO THE FOUR CORNERS REGION AND CENTRAL
ROCKIES. SOME NOCTURNAL SHOWERS MAY PERSIST OVERNIGHT TONIGHT DUE TO
ELEVATED INSTABILITY AND RELATIVELY MOIST AIR MASS...MAINLY OVER THE
WESTERN HALF OF THE FORECAST AREA. THEN ON MONDAY THE CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS WILL AGAIN INCREASE.

THE INCREASED CLOUDS/SHOWERS TODAY AND AGAIN ON MONDAY WILL LOWER
HIGH TEMPERATURES A COUPLE DEGREES EACH DAY.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 400 AM MDT SUN MAY 3 2015

THE LOW MOVING ACROSS THE DESERT SOUTHWEST DISCUSSED IN THE SHORT
RANGE SECTION IS PROGGED TO LIFT ACROSS THE REGION MONDAY NIGHT
INTO TUESDAY. DYNAMIC LIFT AND INCREASED MOISTURE WILL SUSTAIN
NOCTURNAL SHOWERS WITH DAYTIME WARMING RESULTING IN INCREASED
COVERAGE AND INTENSITY TUESDAY AFTERNOON/EVENING. MOISTURE LINGERS
INTO WEDNESDAY FUELING ANOTHER ROUND OF DIURNALLY DRIVEN SHOWERS
AND THUNDERSTORMS.

DRYING BEGINS TO TAKE HOLD OF THE AREA THURSDAY AS A TROUGH OVER
THE WEST COAST DIGS SOUTHWARD OVER NORTHERN CALIFORNIA. AS THE
PATTERN SHIFTS...DRIER AIR FROM OFF THE SOUTHERN CALIFORNIA COAST
SWEEPS ACROSS ARIZONA AND OVER THE FORECAST AREA. CONSEQUENTLY...
EXPECT SHOWERS AND AFTERNOON THUNDERSTORMS WILL BE REDUCED...
FAVORING THE MOUNTAINS ON THURSDAY AND FRIDAY.

THE TROUGH OVER THE WEST LIFTS NORTHEASTWARD FRIDAY NIGHT WITH THE
CENTER PASSING OVER NORTHEAST UTAH ON SATURDAY. THE DEEPEST
MOISTURE WILL BE NORTH OF THE SYSTEM WITH RELATIVELY DRIER AIR
CONTINUING TO SWEEP OVER THE AREA DURING THE DAY. CONSEQUENTLY...
APPEARS THIS SYSTEM WILL BRING LESS SHOWER ACTIVITY TO THE AREA
LATE IN THE WEEK THAN INDICATED IN EARLIER RUNS.

PER PREVIOUS DISCUSSIONS...MOSTLY CLOUDY AND SHOWERY CONDITIONS
TUESDAY AND WEDNESDAY WILL BRING COOLER THAN NORMAL DAYTIME
TEMPERATURES TO THE REGION. THOUGH DRIER AIR ARRIVES DURING THE
LATTER PART OF THE WEEK...COOLER TEMPERATURES IN THE GENERAL
TROUGHING OVER THE WEST WILL INHIBIT WARMING AND EXPECT DAYTIME
TEMPERATURES WILL CONTINUE TO RUN BELOW NORMAL. CONVERSELY...
OVERNIGHT LOWS WILL BE BUOYED BY CLOUD COVER THROUGH MIDWEEK
BEFORE DRYING CAUSES LOWS TO SINK TO SEASONAL NORMS DURING THE
LATTER HALF OF THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1037 AM MDT SUN MAY 3 2015

ISOLATED SHOWERS AND THUNDERSTORMS OVER THE VALLEYS WITH SCATTERED
AND POCKETS OF NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE
MOUNTAINS WILL LIKELY NOT HAVE A SIGNIFICANT IMPACT ON TAFS SITES
TODAY AND THIS EVENING. SHOWERS AND THUNDERSTORMS WILL BE IN THE
VICINITY OF MOST AIRPORTS THROUGH ABOUT 03Z...AND OUTFLOW WIND
GUSTS TO ABOUT 35 MPH ARE EXPECTED. MOUNTAINS WILL BECOME
OCCASIONALLY OBSCURED. CLOUDS AND PRECIPITATION WILL DECREASE
AFTER 03Z.

&&

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

$$

UPDATE...CC
SHORT TERM...EH
LONG TERM...NL
AVIATION...CC



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