Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 072200
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
400 PM MDT TUE JUL 7 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 247 PM MDT TUE JUL 7 2015

REX BLOCKING OFF THE LEFT COAST AND A STUBBORN DOWNSTREAM TROUGH
OVER THE UPPER MIDWEST IS KEEPING WEAK ENERGY AND MOISTURE TRAPPED
OVER THE ROCKIES AND GREAT BASIN. BOTH OF THESE ARE COMBINING WITH
AFTERNOON INSTABILITY TO CREATE SLOW MOVING STORMS...SOME WITH SMALL
HAIL AND VERY HEAVY RAINFALL THIS AFTERNOON. THE NORTHERN STREAM
TROUGH OVER THE EAST BEGINS TO BREAK DOWN TOMORROW...LEADING TO A
SLOW TRANSFORMATION OF THE FLOW PATTERN GOING INTO THE LATE WEEK
PERIOD. THETA SURFACES NEAR 315K INDICATE THE VERY MOIST CONDITIONS
OVER THE WESTERN DESERTS WILL CONTINUE TO DRAW MOISTURE INTO THE
GREAT BASIN. THE MAIN LOW PRESSURE SYSTEM MOVING ONSHORE IN CENTRAL
CALIFORNIA WILL BE FORCING THE LAST IN A SERIES OF SHORT WAVE
TROUGHS ACROSS EASTERN UTAH LATE TONIGHT AND THEN COLORADO TOMORROW.
SKIES SHOULD REMAIN FAIRLY CLOUDY IN THIS MOIST ATMOSPHERE WITH
CONVECTIVE ACTIVITY WANING BUT NOT SHUTTING OFF OVERNIGHT. THE
SHOWERS SHOULD BE RE-INVIGORATED BY AFTERNOON INSTABILITY FROM
NORTHERN UTAH TO SOUTHEAST COLORADO AS POTENTIAL INSTABILITY
INCREASES. DRIER AIR WILL BE INVADING FORM THE SOUTHWEST BY
WEDNESDAY EVENING AS SHORT WAVE RIDGING BUILDS INTO THE 4 CORNERS
REGION. THIS DRY AIR OVER-RUNNING MOIST PBL CONDITIONS...WITH A
HINT OF A WARM FRONT ARCING FROM NORTHERN NEW MEXICO TO SOUTHERN
UTAH...SHOULD KEEP SOME CONVECTION FIRING INTO THE EVENING ACROSS
OUR WESTERN CWA AS SHOWERS SLOWLY EXIT THE NORTHEAST. CLOUD COVER
AND PRECIPITATION KEPT HIGHS QUITE COOL TODAY AND THIS TREND
CONTINUES FOR WEDNESDAY AND DID TREND BELOW GUIDANCE MOST AREAS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 247 PM MDT TUE JUL 7 2015

FROM THURSDAY INTO EARLY NEXT WEEK THE DOMINATE FEATURE
IN THE CONUS WILL BE THE SUB-TROPICAL HIGH BUILDING OUT OF THE
SOUTHEAST STATES INTO THE SOUTHERN PLAINS. THE HIGH WILL BE STRONG
ENOUGH TO KEEP THE MAIN AREA OF LOW PRESSURE TO OUR WEST BEFORE IT
LIFTS OUT ACROSS THE NORTHERN ROCKIES BY WEEK/S END. SOUTHWEST FLOW
BETWEEN THESE FEATURES LATE WEEK WILL CAUSE SOME BREEZY AFTERNOON
CONDITIONS WHILE GENERALLY ADVECTING IN DRIER AIR. THE DOWNTURN IN
AFTERNOON CONVECTION WILL BE GRADUAL WITH MODELS CONTINUING TO
FIRE STORMS ACROSS THE WESTERN COLORADO TERRAIN THURSDAY INTO
FRIDAY AFTERNOONS. THIS COVERAGE WILL BE LESS THAN DAYS PAST AND
THE THREAT OF HEAVY RAINFALL DECREASING EACH DAY. MAINLY DRY
CONDITIONS ANTICIPATED BY SATURDAY WITH ONLY A STRAY STORM OR TWO
IN THE AFTERNOON HEATING. AS SUCH TEMPERATURES...THOUGH REMAINING
BELOW NORMAL...WILL GRADUALLY INCREASE EACH DAY THROUGH THE
WEEKEND. THE BIG QUESTION REMAINS...WHEN WILL THE MOISTURE RETURN.
THE IS HIGHLY DEPENDENT ON THE LOCATION WHERE THE SUBTROPICAL HIGH
CENTER SETTLES. THE EURO HAS THIS HIGH FARTHER SOUTH AND WEST
COMPARED TO THE GFS AND KEEPS AN OVERALL DRIER FORECAST INTO EARLY
NEXT WEEK AS THE MONSOON PLUME IS DIRECTED TO OUR WEST. THE GFS
TAPS THE MOISTURE BY SUNDAY AFTERNOON AND THE FORECAST IS
THEREFORE WETTER GOING INTO THE NEW WEEK. CONFIDENCE LOW IN EITHER
SOLUTION AT THIS POINT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1104 AM MDT TUE JUL 7 2015

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE
ACROSS MUCH OF THE REGION THROUGH THE NEXT 24 HOURS. THOUGH
MOUNTAINS REMAIN FAVORED...A NUMBER OF AIRPORTS WILL EXPERIENCE
MODERATE TO HEAVY RAIN AT TIMES. AIRPORTS WITH ILS BREAKPOINTS AT
OR ABOVE 4500 FEET MAY BE BRIEFLY IMPACTED. EXPECT A DECREASE IN
COVERAGE TONIGHT...HOWEVER A WEAK DISTURBANCE WILL SUSTAIN SOME
SHOWERS THROUGH WEDNESDAY MORNING.


&&

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

$$

SHORT TERM...15
LONG TERM...15
AVIATION...NL



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