Weather Service Report


861 
FXUS65 KGJT 301716
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1116 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 1115 AM MDT SUN AUG 30 2015

THE MORNING SOUNDINGS AROUND THE REGION SHOW A MID-LEVEL INVERSION
THAT IS NOT CAPTURED BY THE LATEST MODEL RUNS. THEREFORE THE SHORT
TERM QPF FIELDS ARE MORE ROBUST THAN REALITY. A WEAK PASSING WAVE
IN NE UTAH THIS LATE MORNING SHOWS THAT POTENTIAL ENERGY CAN BE
TAPPED WITH LIGHTNING NOW TRACKING INTO NW COLORADO. THE BOUNDARY
LAYER STILL REMAINS DRY WITH SFC DEWPOINTS IN THE 40S. AFTERNOON
STORMS WILL INITIALLY PRODUCE MORE LIGHTNING AND WIND THAN RAIN
AND THE 12Z MODEL TREND HAS SHOWN THIS SLOWER MOISTENING OF THE
LOWER LAYERS OF THE ATMOSPHERE.

THIS EVENING DEEP MOISTURE WILL BE PULLED FIRST INTO SE UTAH.
THEN NAM SHOWS PRECIP WATER VALUES OF 1.3 INCHES THERE SPREADING
QUICKLY INTO NE UT-NW CO THIS EVENING. THIS EVENING WILL LIKELY
HAVE THE MOST THUNDERSTORM AND SHOWER COVERAGE. STORM MOTION WILL
BE TO THE NE AT 20-25 MPH FOR SOME POTENTIAL OF LOCALLY STRONG
WIND GUSTS. SOME FORCING (DIV Q FIELD) SEEN ACROSS NE UT THIS
AFTERNOON AND ACROSS NW COLORADO LATE TONIGHT FOR SOME
THUNDERSTORMS CONTINUING THROUGH THE NIGHT. CLOUDS AND CONVECTIVE
WINDS WILL KEEP TEMPERATURES MILD OVERNIGHT.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 446 AM MDT SUN AUG 30 2015

THE RIDGE OF HIGH PRESSURE OVER THE REGION WILL SLOWLY PUSH EAST
AS SEVERAL DISTURBANCES ROTATE AROUND THE BROAD TROUGH OF LOW
PRESSURE OVER THE NORTHWEST US. THE FIRST DISTURBANCE WILL ROTATE
THROUGH THE GREAT BASIN INTO THE NORTHERN ROCKIES LATER TODAY. AS
THIS WAVE MOVES THROUGH...INCREASING SOUTHWEST FLOW OVER THE AREA
WILL ALLOW MOISTURE TO INCREASE DURING THE DAY WITH PRECIPITABLE
WATER VALUES EXCEEDING AN INCH OVER SOUTHERN AND WESTERN SECTIONS.
AS A RESULT...WE WILL SEE BETTER COVERAGE OF PRECIPITATION WITH
SOME STRONGER THUNDERSTORMS DEVELOPING DURING THE AFTERNOON AND
EARLY EVENING HOURS. AT THE ONSET...COULD ALSO SEE SOME GUSTY
OUTFLOW WINDS TO 45 MPH IN AND NEAR THE STORMS. EXPECT STORMS TO
DIMINISH OVERNIGHT. SLIGHTLY DRIER AIR WILL MOVE ACROSS NORTHERN
SECTIONS OF THE FORECAST AREA DURING THE DAY ON MONDAY. HOWEVER...
SHOULD SEE ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING DURING THE DAY WITH BEST FOCUS OVER THE SOUTHERN HALF
OF THE FORECAST AREA. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE
NORMAL THROUGH THE SHORT TERM.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 446 AM MDT SUN AUG 30 2015

NOCTURNAL SHOWERS AND THUNDERSTORMS REMAIN IN THE PICTURE MONDAY
NIGHT AS 45-50 KT SOUTHWEST TO NORTHEAST ORIENTED SUBTROPICAL JET
LINGERS OVER THE AREA. DON/T EXPECT THIS ACTIVITY TO BE VERY
WIDESPREAD OR STRONG. AS MENTIONED IN THE PREVIOUS SECTION...DRIER
AIR FROM THE SOUTHWEST WILL CONTINUE TO FILTER INTO THE REGION
TUESDAY. PRECIPITABLE WATER FALLS TO NEAR 0.60 TO 0.75 OF AN INCH
WHICH IS MORE THAN SUFFICIENT TO FUEL SCATTERED SHOWERS AND
THUNDERSTORMS OVER COLORADO/S DIVIDE MOUNTAINS. 

SYNOPTIC PATTERN EVOLVES LITTLE THROUGH MIDWEEK WITH THE LONG WAVE
TROUGH REMAINING OVER THE PACIFIC NORTHWEST AND HIGH PRESSURE OVER
THE CENTRAL PLAINS. CONSEQUENTLY...DRY SOUTHWEST FLOW WILL PERSIST
AND...THEREFORE...ONLY EXPECT A FEW STORMS ALONG THE DIVIDE
WEDNESDAY AND THURSDAY. MODELS SUGGEST THE NORTHWESTERN TROUGH
AXIS WILL SHIFT INLAND OVER THE NORTHERN INTERMOUNTAIN REGION AT
THE END OF THE WEEK. THIS...IN TURN...WILL ALLOW MOISTURE TO
FILTER BACK INTO THE REGION FROM THE SOUTH MARKING AN UPTICK IN
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY.

MODELS STILL INDICATING NEAR NORMAL TEMPERATURES THROUGHOUT THE
EXTENDED PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY NOON) 
ISSUED AT 1115 AM MDT SUN AUG 30 2015

THUNDERSTORMS WILL INCREASE IN COVERAGE THROUGH THE AFTERNOON.
STORMS WILL INITIALLY BE HIGH-BASED WITH CIGS ABV ILS BREAK
POINTS. GUSTY OUTFLOW WINDS OF 25 TO 35 MPH ARE THE MAIN THREAT
THIS AFTERNOON. AFTER 23Z...THERE IS A GOOD CHANCE THAT SOME
STORMS WILL MOVE OVER AIRPORTS ACROSS THE REGION BRINGING OUTFLOW
WINDS TO 35 MPH OR MORE ALONG WITH A BRIEF LOWERING OF CIGS.
KASE...KEGE AND KRIL FACE A GOOD CHANCE FOR CIGS LOWER THAN ILS
BREAKPOINTS FOR SHORT PERIODS FROM 23Z THROUGH 03Z/MON. SCATTERED
SHOWERS AND EMBEDDED THUNDERSTORMS WILL LINGER OVER THE REGION
THROUGH THE NIGHT AND THROUGH MONDAY MORNING.


&&

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

$$

UPDATE...JOE
SHORT TERM...MPM
LONG TERM...NL
AVIATION...NL/JOE

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