Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 041033
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
433 AM MDT TUE AUG 4 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 433 AM MDT TUE AUG 4 2015

HIGH PRESSURE BUILDS OVER THE REGION TODAY RESULTING IN A DRAMATIC
CHANGE FROM THE RECENT COOL AND STORMY WEATHER. HOWEVER...A FEW
ISOLATED THUNDERSTORMS REMAIN POSSIBLE OVER THE HIGH TERRAIN THIS
AFTERNOON...BUT OTHERWISE CONDITIONS WILL BE DRY. HIGHS WILL
REBOUND TO NEAR NORMAL TODAY...RISING SLIGHTLY ABOVE NORMAL ON
WEDNESDAY. ALSO ON WEDNESDAY...A 500 MB TROUGH FEATURE BRUSHING
NORTHERN UTAH AND SOUTHWEST WYOMING WILL CAUSE THE PRESSURE
GRADIENT TO TIGHTEN YIELDING INCREASED WINDS DURING THE AFTERNOON.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 433 AM MDT TUE AUG 4 2015

MODELS INDICATED THAT THE BREAK IN THE MONSOONAL PATTERN WILL
CONTINUE INTO THURSDAY. A LOW PRESSURE SYSTEM MOVING EASTWARD
ACROSS THE NORTHERN ROCKIES WILL FLATTEN THE RIDGE OVER THE AREA
BRINGING A DRY WESTERLY FLOW. HOWEVER...THERE IS A SMALL CHANCE
THAT THERE MAY BE SUFFICIENT MOISTURE TO FUEL A HANDFUL OF STORMS
OVER THE MOUNTAINS ALONG THE DIVIDE DURING THE AFTERNOON AND EARLY
EVENING.

THE NEXT MONSOONAL SURGE ARRIVES FRIDAY AS A LOW PRESSURE SYSTEM
OVER THE EASTERN PACIFIC MOVES ASHORE OVER CENTRAL CALIFORNIA. IN
RESPONSE...HIGH PRESSURE SHIFTS EASTWARD TO THE TEXAS PANHANDLE
ALLOWING SOUTHWEST WINDS TO CARRY MOISTURE FROM THE MEXICAN PLATEAU
ACROSS THE AREA. PRECIPITABLE WATER (PW) VALUES ARE INDICATED TO
RISE MARKEDLY...ESPECIALLY OVER SOUTHEAST UTAH WHERE PW WILL RISE
TO NEAR AN INCH BY DAYS END. THIS WILL RESULT IN AN INCREASE IN
SHOWER AND THUNDERSTORM COVERAGE...ESPECIALLY ACROSS THE SOUTHERN
MOUNTAINS.

MOISTURE DEPTH ACROSS THE FORECAST AREA WILL INCREASE SATURDAY AS
SOUTHWEST FLOW CONTINUES TO BRING MONSOON MOISTURE TO THE REGION.
A SHORTWAVE TROUGH EJECTED FROM THE WEST COAST LOW PRESSURE SYSTEM
WILL SWEEP NORTHEASTWARD ACROSS THE GREAT BASIN PROVIDING SOME
ADDITIONAL LIFT. CONSEQUENTLY...EXPECT AN INCREASE IN BOTH
INTENSITY AND COVERAGE OF THUNDERSTORMS SATURDAY AFTERNOON INTO
SATURDAY EVENING.

AS THE SHORTWAVE CONTINUES ACROSS THE NORTHERN ROCKIES...FLOW
REVERTS TO A DRIER ZONAL ORIENTATION WHICH WILL CAUSE STORMS TO
DECREASE SUNDAY AND MONDAY.

HIGHS WILL BE NEAR NORMAL IN ZONAL FLOW THURSDAY...TRENDING
DOWNWARD FRIDAY AND SATURDAY AS THE MONSOON REASSERTS ITSELF.
DRYING WILL BRING WARMING SUNDAY INTO MONDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 433 AM MDT TUE AUG 4 2015

EXPECT A FEW THUNDERSTORMS OVER THE HIGHER TERRAIN FROM 18Z TO
02Z/WED. THIS ACTIVITY IS UNLIKELY TO IMPACT AIRPORTS ACROSS THE
REGION AND VFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE NEXT
24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 433 AM MDT TUE AUG 4 2015

FIRE WEATHER CONCERNS ARE POSSIBLE WEDNESDAY IN EASTERN UTAH AND
NORTHWEST COLORADO WHERE FUELS ARE CRITICAL DUE TO INCREASED
WINDS FROM A PASSING WEATHER DISTURBANCE TO THE NORTH. RIGHT NOW
FORECAST MODELS SHOW BORDERLINE MINIMUM RELATIVE HUMIDITY VALUES
WEDNESDAY AFTERNOON...BUT WIND GUSTS GREATER THAN 25 MPH ARE WELL
SUPPORTED. WILL KEEP AN EYE OUT FOR POTENTIAL PROBLEMS WEDNESDAY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

$$

SHORT TERM...JAM
LONG TERM...NL
AVIATION...NL
FIRE WEATHER...JAM


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