Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KGJT 062109
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
309 PM MDT WED MAY 6 2015

.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 309 PM MDT WED MAY 6 2015

THE STRONG LOW THAT MOVED OVER THE AREA LAST NIGHT AND THIS
MORNING WILL CONTINUE MOVING INTO THE HIGH PLAINS TONIGHT.
NW AND CENTRAL CO AND NE UT WILL BE BENEATH THE NW FLOW ALOFT
ON THE WEST SIDE OF THE STORM...WHERE UNSTABLE AND MOIST
CONDITIONS WILL CONTINUE TO PRODUCE RAIN SHOWERS AND THUNDERSTORMS
OVER MUCH OF THE AREA. A FEW STORMS HAVE BEEN STRONG ENOUGH TO
PRODUCE SMALL HAIL AND HEAVY RAIN. A WEAK SHORTWAVE TROUGH MOVING
OVER NORTHWEST CO AND NE UT WILL ALSO AS SOME SUPPORT FOR
CONVECTION UNTIL ABOUT 03Z THIS EVENING. SUBSIDENCE AND GRADUALLY
DRIER AIR WILL FILTER INTO EASTER UT...AND NORTHWEST AND CENTRAL
CO AFTER MIDNIGHT. OVER SW CO...THE HRRR AND NAM12 SHOW ANOTHER
WEAK SHORTWAVE WILL BRING INCREASING CLOUDS AND ISOLATED
PRECIPITATION LATE TONIGHT.

THURSDAY MORNING...IN SOUTH FLOW A WEAK WAVE WORKS THROUGH THE
FOUR CORNERS REGION. AVAILABLE MOISTURE WILL BE DIMINISHING THERE
SO ONLY ISOLATED SHOWERS ARE FORECASTED ACROSS THE SOUTH FAVORING
THE SAN JUANS. DEEPER MOISTURE REMAINS ACROSS THE NORTH THURSDAY
ALONG WITH SOME WEAK FRONTAL FORCING. MARGINAL AFTERNOON
INSTABILITY WILL LIMIT THUNDERSTORM COVERAGE MAINLY OVER MTNS
NORTH OF I-70.

TONIGHT DRIER SW FLOW INVADES LIMITING NIGHTTIME SHOWERS TO NEAR
THE CONTINENTAL DIVIDE. TEMPERATURES REMAIN NEAR NORMAL.

THE NEXT STRONGER PACIFIC LOW SINKS THROUGH CALIFORNIA ON THURSDAY
THEN BEGINS TO AMBLE INLAND THURSDAY NIGHT.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 309 PM MDT WED MAY 6 2015

A HIGHLY AMPLIFIED PROGRESSIVE PATTERN CONTINUES THROUGH THESE
PERIODS. ONE STRONG UPPER LOW WILL PASS ON SATURDAY BRINGING A
BLAST OF NORTHERN AND MOUNTAIN SNOW. TWO OTHER TROUGHS CURRENTLY
ARE TIMED TO PASS MID TO LATE NEXT WEEK.

FRIDAY THE UPPER LOW WITH A MODIFYING BUT IMPRESSIVE -26C COLD
CORE WORKS NORTH OF LAS VEGAS TO SOUTHCENTRAL UTAH FRIDAY NIGHT
AND THROUGH THE FORECAST AREA ON SATURDAY. THE THERMAL RIDGE
BLOSSOMS OVER THE FORECAST AREA FRIDAY AND HAVE RAISED
TEMPERATURES CLOSER TO THE WARMER NAM GUIDANCE. A 70KT JET NOSE
POKES INTO SE UTAH IN THE AFTERNOON AND RAKES THE SOUTH OVERNIGHT.
COOL ADVECTION ALOFT BEGINS TO DESTABILIZE BUT AVAILABLE MOISTURE
IS LIMITED AND MAINLY ACROSS THE NORTH.

SATURDAY THE POTENTIAL VORTICITY CENTER RAKES THE NORTH AS THE
JET WRAPS UP THE FRONT RANGE. FRONTAL FORCING SEEN IN THE PARK
RANGE BY THE AFTERNOON. THE BEST SHOWER COVERAGE WILL BE OVER THE
NORTHERN MOUNTAINS BUT WILL EXTEND INTO THE CENTRAL CO MTNS. SNOW
LEVELS DROP TO AROUND 8KFT...AND WILL BRIEFLY BE LOWER IN
STRONGER CONVECTION. THE LOW LIFTS THROUGH THE NORTHERN PLAINS
SATURDAY NIGHT THROUGH SUNDAY. WRAP- AROUND MOISTURE WILL CONTINUE
TO PRODUCE SHOWERS FAVORING THE NORTH. SUNDAY...SNOW LEVELS LOWER
INTO THE NORTHERN VALLEYS WITH 700MB TEMPS AT -4C THERE.

SIGNIFICANT SNOWFALL IS EXPECTED FOR THIS WEEKEND FOR THE EASTERN
UINTAS AND THE COLORADO MOUNTAINS FROM WYOMING DOWN INTO THE NW
SAN JUANS. TRAVEL THROUGH THESE MOUNTAINS COULD BE HAZARDOUS THIS
WEEKEND. COLDER THAN NORMAL TEMPERATURES EXPECTED ACROSS THE
REGION THROUGH SUNDAY NIGHT. HIGH VALLEY FREEZES ARE POSSIBLE.

MONDAY WARM ADVECTION BEGINS AS A RIDGE BUILDS IN FROM THE WEST.
FLOW ALOFT QUICKLY SWITCHES BACK TO SW AND INCREASES INTO THE NEW
WEEK AS THE NEXT TROUGH WORKS INTO THE PACIFIC NW ON TUESDAY AND
THE GREAT BASIN ON WEDNESDAY. AN ASSOCIATED ZONAL JET FROM CENTRAL
CALIFORNIA INTRUDES INTO THE NORTHERN-CENTRAL FORECAST AREA ON
WEDNESDAY BEGINNING THE CHANCE OF MAINLY RAIN SHOWERS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1055 AM MDT WED MAY 6 2015

MOISTURE CONTINUES TO WRAP INTO EASTERN UTAH AND WESTERN COLORADO
BEHIND A SYSTEM RETREATING INTO THE HIGH PLAINS. THIS IS KEEPING
WIDESPREAD RAIN AND SNOW SHOWERS OVER THE COLORADO MOUNTAINS ALONG
WITH OBSCURATION OF MUCH OF THE RIDGELINES AND PEAKS. SUNSHINE
IN EASTERN UTAH HAS HELPED DESTABILIZE THE ATMOSPHERE ENOUGH TO
BEGIN TO PRODUCE ISOLATED THUNDERSTORMS. THESE WILL BECOME MORE
SCATTERED OVER CENTRAL AND NORTHERN PORTIONS OF COLORADO THIS
AFTERNOON. MVFR CONDITIONS ARE BEING IN PLACE OVER THE MOUNTAIN
FORECAST TERMINALS OF WESTERN COLORADO AND THIS WILL CONTINUE TO
BE POSSIBLE THROUGH THE REMAINDER OF THE AFTERNOON. IN THE LOWER
ELEVATIONS VFR WILL DOMINATE...BUT MAY TEMPORARILY DROP DOWN TO
MVFR IF A HEAVIER SHOWER IS IN THE VCNTY. DRIER AIR INVADES
THROUGH THE NIGHT AND OVERALL IMPROVEMENT IS EXPECTED. HOWEVER
VALLEY FOG MAY BECOME MORE OF A PROBLEM AND WILL BE MONITORING
THIS THREAT FOR FUTURE FORECAST ISSUANCES.


&&

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

$$

SHORT TERM...CC/JOE
LONG TERM...JOE
AVIATION...TGJT


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.