Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 312156
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
356 PM MDT FRI JUL 31 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI JUL 31 2015

TONIGHT...
THE TONGUE OF DEEP SUBTROPICAL MOISTURE WILL REMAIN POSITIONED
OVER AZ/NM TO THE EASTERN SIDE OF THE COLORADO ROCKIES. SOME OF
THIS DEEPER MOISTURE WILL EXTEND ACROSS OUR SOUTHERN BORDER AND
ACROSS THE SAN JUAN AND ABAJO MOUNTAINS...AND ALONG OUR EASTERN
EDGE NORTHWARD TO AROUND THE CENTRAL MOUNTAINS. MUCH DRIER AIR
COVERS THE NORTHERN PORTION OF THE FORECAST AREA WITH A STRONG
MOISTURE GRADIENT BETWEEN THE TWO. THEREFORE EXPECT SHOWERS AND
THUNDERSTORMS TO CONTINUE TO INCREASE LATE THIS AFTERNOON OVER THE
WETTER AREAS OF THE FORECAST AREA...ROUGHLY SOUTH OF A LINE FROM
THE ASPEN/VAIL PASS AREAS SOUTHWEST TO PAGE AZ. ALSO AN AREA OF
THUNDERSTORMS OVER NORTHWEST NM LOOKS LIKE IT WILL MOVE INTO
SOUTHWEST CO LATE THIS AFTERNOON. GOOD CONVECTION WILL CONTINUE
INTO THE EARLY EVENING WITH COVERAGE OVER SOME VALLEYS INCREASING
FOR A SPELL. AFTER SUNSET...MOST ACTIVITY WILL DIMINISH AND WILL
BECOME MORE SHOWERY (LESS THUNDERY) BY MIDNIGHT. A FEW NOCTURNAL
STORMS WILL BE POSSIBLE OVER THIS WETTER PORTION OF THE AREA.
NIGHTTIME TEMPERATURES WILL REMAIN BELOW NORMAL IN THE DRIER AIR
OVER THE NORTH...AND AROUND NORMAL UNDER THE MORE MOIST AIR MASS
TO THE SOUTH.

SATURDAY AND SATURDAY NIGHT...
NOT MUCH DIFFERENT THINKING FROM PREVIOUS PACKAGE...STILL
EXPECTING SLOW NORTHWARD MOVEMENT OF MID LEVEL MOISTURE A LITTLE
FURTHER INTO CENTRAL PORTION OF THE CWA ON SATURDAY. THEN
EMBEDDED DISTURBANCE IN SOUTHERLY FLOW EXPECTED TO BEGIN MOVING
NORTHWARD AND HELPING TO DRAW THE MOISTURE INTO THE NORTHERN
PORTION OF OUR CWA SATURDAY NIGHT. SO EXPECT LINGERING SHOWERS AND
ISOLATED THUNDERSTORMS SATURDAY NIGHT MAINLY SOUTHERN PORTION OF
OUR CWA. WITH INCREASING CLOUDS SATURDAY NIGHT...MIN TEMPERATURES
SHOULD BE SIGNIFICANTLY MILDER THAN TONIGHT. RAISED MIN
TEMPERATURES IN MOST ZONES FOR SATURDAY NIGHT...AND IN SOME ZONES
THEY MAY NEED TO RAISED EVEN A LITTLE HIGHER.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI JUL 31 2015

SUNDAY AND SUNDAY NIGHT...
SUNDAY THROUGH SUNDAY EVENING SHOULD BE A RATHER ACTIVE TIME FOR
CONVECTIVE DEVELOPMENT ACROSS OUR CWA...WITH COMBINATION OF
DAYTIME HEATING AND DYNAMIC LIFT...ALONG WITH MORE LOW LEVEL
MOISTURE. PRECIPITABLE WATER VALUES RISE SIGNIFICANTLY DURING THIS
TIME PERIOD...GENERALLY RANGING FROM NEAR 0.75 TO 1.25 OF AN INCH.
STORMS WILL LIKELY BE MOVING RELATIVELY SLOWLY...LIKELY IN THE 10
TO 15 KNOT RANGE...AND THUS WE WILL LIKELY BE DEALING WITH
SOME FLASH FLOODING CONCERNS.

MONDAY THROUGH THURSDAY NIGHT...
DRIER AIR MOVES INTO OUR CWA BY EARLY MONDAY...IN THE WAKE OF THE
SHORTWAVE DISTURBANCE. SIGNIFICANT DOWNTURN IN SHOWERS AND
THUNDERSTORMS THAT SHOULD CONTINUE DURING THIS PERIOD TO THE NORTH
OF AN E-W ELONGATED UPPER HIGH THAT WILL LEAVE OUR CWA UNDER A
DRIER WESTERLY FLOW ALOFT. CONSEQUENTLY...MAX TEMPERATURES WILL
REBOUND. RAISED MAX TEMPS ABOUT 5 DEGREES F FROM PREVIOUS GRIDS
ON MONDAY FOR MUCH OF OUR CWA. AND MAX TEMPERATURES TUESDAY MAY
YET BE A TAD TOO COOL.

FRIDAY...
NOW LOOKS LIKE NEXT SURGE OF MOISTURE FROM THE SOUTH WILL WAIT
UNTIL FRIDAY TO BEGIN SPREADING INTO OUR CWA...AS UPPER HIGH
CENTER SHIFTS A LITTLE FURTHER EAST AND THE FLOW AROUND THE UPPER
HIGH BECOMES MORE CONSOLIDATED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1057 AM MDT FRI JUL 31 2015

MID LEVEL CLOUDS HAVE MOVED OVER SOUTHWEST CO AND SOUTHEAST UTAH
THIS MORNING. THESE CLOUDS WILL CONTINUE TO GRADUALLY SPREAD
NORTH...BUT WILL MAINLY STAY SOUTH OF THE INTERSTATE 70 CORRIDOR.
CLOUDS ALSO WILL THICKEN WITH THE CHANCE FOR SHRA/TSRA INCREASING
DURING THE AFTERNOON ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA. AFTER AROUND 20Z SCATTERED TO NUMEROUS SHRA/TSRA WILL
DEVELOP OVER THE SRN MOUNTAINS AND EXPAND SOUTHWARD OVER THE
VALLEYS OF SW COLORADO AND SE UTAH. GUSTY OUTFLOW WINDS
(G30-40KTS) AND LOCAL +SHRA WILL BE POSSIBLE FROM
THUNDERSTORMS...WITH MOUNTAINS OBSCURED AT TIMES. VFR CONDITIONS
WILL PREVAIL...ALTHOUGH ILS CIGS MAY OCCUR FROM ANY PASSING
THUNDERSTORMS. SCATTERED SHRA/TSRA WILL CONTINUE INTO THE EVENING
BUT GRADUALLY DIMINISH TOWARD MIDNIGHT. ISOLATED -SHRA/-TSRA MAY
PERSIST THROUGH SAT MORNING.

&&

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

$$

SHORT TERM...EH/JRP
LONG TERM...JRP
AVIATION...EH



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