Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 030000
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
600 PM MDT WED SEP 2 2015

.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 303 PM MDT WED SEP 2 2015

THE UPPER JET SUPPORT FROM THE PAST FEW DAYS HAS LIFTED TO OUR
NORTH THIS AFTERNOON. AS A RESULT THE STORMS ARE A BIT LESS ROBUST
BUT ARE FAVORING MUCH OF THE SAME AREA OF DEVELOPMENT AS 24 HOURS
AGO. PWAT HAS NOT CHANGED MUCH AND IS RUNNING JUST UNDER AN INCH
IN MOST AREAS. WITH SHEAR ON THE WEAK SIDE MULTICELL STORM MODE
IS FAVORED. EXPECT SOME VALLEYS TO GET IN ON THE ACTION AS WELL
BUT MAINLY AS LIGHT PCPN AS THE STORMS WEAKEN COMING OFF THE
TERRAIN THROUGH EARLY EVENING. THAT CHANGES OVERNIGHT HOWEVER.
VERY DISTINCT CURL (MCV?) SEEN IN WATER VAPOR AND VISIBLE
SATELLITE OVER EASTERN ARIZONA TODAY. THIS FEATURE WILL LIFT
TOWARD THE 4 CORNERS THROUGH THE EVENING THEN SHEAR OUT ACROSS OUR
CWA OVERNIGHT. THE SHORT TERM HI-RES MODELS AND TO SOME EXTENT THE
NAM/GFS HAS PICKED UP ON THIS AS WELL AS A NEW SUBTROPICAL JET
STREAK. TWEAKED THE INHERITED POPS WHICH ALREADY HINTED WELL AT
THIS SCENARIO OF OVERNIGHT PRECIPITATION. CLOUD COVER SHOULD HELP
TEMPERATURES STAY UP A FEW DEGREES OVER THE PAST FEW NIGHTS.

MODELS CONTINUE TO DEPICT INCREASED CONVECTIVE COVERAGE THURSDAY
FOR REASONS THAT HAVE BEEN SIMILAR AS OF LATE. MOISTURE CONTINUES
TO ADVECT INTO THE REGION FROM THE SOUTHWEST THANKS TO LOW
PRESSURE TO THE NW AND HIGH PRESSURE TO THE EAST. A SHORTWAVE/VORT
MAX AND WEAK...BUT SUPPORTING UPPER LEVEL JETLET...WILL BE THE
FOCUS OF CONVECTION FROM DAYBREAK ONWARDS. AS THIS DISTURBANCE
MOVES ACROSS THE REGION...PRECIP AMTS AND COVERAGE WILL INCREASE.
ONLY CAVEAT WILL BE CLOUD COVER INHIBITING SAID CONVECTION. THIS
HAS OCCURRED A FEW TIMES THIS SUMMER SO WILL BE INTERESTING TO SEE
IF IT DOES SO AGAIN. FOR NOW...MOSTLY KEPT POPS AS IS IF NOT
RAISING THEM SOME. MOST PRECIP WILL END BY THE EVENING HOURS
GIVING WAY TO A MOSTLY UNEVENTFUL NIGHT.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 303 PM MDT WED SEP 2 2015

SIMILAR CONDITIONS EXPECTED FRIDAY AS THE LOW PRESSURE TO OUR NW
STARTS TO DROP DOWN THE COAST. EVEN THOUGH THE LOW DOES MOVE THE
END RESULT IS THE SAME...LITTLE CHANGE IN MOISTURE CONTENT AS
IMPULSES CAUSE MORE SHOWERS AND THUNDERSTORMS TO FORM. GFS IS VERY
AGGRESSIVE WITH PRECIP AMTS LATE FRIDAY NIGHT WHILE NAM12 REALLY
PULLS BACK. APPEARS GFS IS FOCUSING ON 70KT JET STREAK ALONG WITH
SOME DECENT UPPER LEVEL DIVERGENCE OVERNIGHT WHILE NAM...NOT SO
MUCH. CURRENT POPS LOOKED GOOD SO MINIMAL CHANGES THERE.

SATURDAY IS A MORE IN BETWEEN DAY AS THE LOW PRESSURE NOW OVER NRN
CALIF/WRN NV BEGINS SWINGING EASTWARD CAUSING THE STREAM OF
MOISTURE TO DO LIKEWISE. PWATS ARE FORECAST TO DROP SATURDAY
WHICH IS WHY MODELS ALSO SHOW MINIMAL CONVECTION. ON SUNDAY...THE
LOW PRESSURE WILL HAVE SWUNG BACK NORTHWARD TO SRN MT AND AS IT
DOES SO..A WEAK COOL FRONT LOOKS TO JUST CLIP OUR NORTHERN ZONES
AS THICKNESSES DROP WITH FORECAST HIGH TEMPS ALSO DROPPING BY 8
TO 10 DEGREES. EVEN SO..SUNDAY LOOKS TO BE A RATHER CALM DAY FOR
MUCH OF THE CWA.

MONDAY AND TUESDAY BRINGS A RETURN TO THUNDERSTORMS AND RAINSHOWERS
AS MOISTURE FUNNELS INTO THE REGION THANKS TO A TROUGH OUT WEST
AND HIGH PRESSURE EAST. HOWEVER...WEDNESDAY AND BEYOND LOOKS DRY
AS THE STREAM OF MOISTURE SHIFTS TO THE FRONT RANGE.

TEMPS THROUGH THE ENTIRE PERIOD LOOK TO RUN NEAR NORMAL IF NOT
BELOW DUE TO CLOUD COVER AND PRECIPITATION.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 600 PM MDT WED SEP 2 2015

SCATTERED BUT SHORT LIVED -TSRA WILL CONTINUE UNTIL 03Z THIS
EVENING OVER SW COLORADO. FOR NW COLORADO...ANY -TSRA WILL BE
LOCAL AND SHORT LIVED.

A SHORT WAVE OVER ARIZONA WILL SPREAD MOISTURE INTO SW COLORADO
AFTER 09Z TONIGHT WITH SCATTERED -SHRA SPREADING TOWARD THE I70
CORRIDOR. CIGS MAY FALL BELOW ILS BREAKPOINTS AT KTEX AND KDRO AS
-SHRA MOVE OVERHEAD. -SHRA WILL EVOLVE INTO -TSRA...ESPECIALLY
AFTER 18Z THURSDAY WHEN -TSRA/-SHRA INCREASES WITH 30-50 PERCENT
AREAL COVERAGE.

NORTHEAST UTAH...NO SIGNIFICANT WEATHER EXPECTED THROUGH 18Z
THURSDAY...THEN ISOLATED -TSRA.

&&

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

$$

SHORT TERM...15/TGR
LONG TERM...TGR
AVIATION...PF



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