Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 082142
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
342 PM MDT TUE JUL 8 2014

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 342 PM MDT TUE JUL 8 2014

THIS FORECAST AREA IS BEING SQUEEZED BETWEEN THE DEEP MONSOONAL
MOISTURE TO THE SW AND THE RELATIVELY COOL AND MOIST AIR MASS ON
THE FRONT RANGE. THE FRONTAL BOUNDARY ALONG THE CONTINENTAL DIVIDE
IS PROVIDING A FOCUS FOR AFTERNOON CONVECTION. STORM MOTION IS
VERY NEARLY ZERO SO LOCALLY HEAVY MOUNTAIN SHOWERS ARE POSSIBLE
ESPECIALLY OVER THE SAN JUANS. WITH NO UPPER FORCING EVIDENT FOR
TONIGHT MOST STORMS WILL END WITH SUNSET. BUT BOUNDARY INTERACTION
MAY KEEP ISOLATED STORMS BEYOND MIDNIGHT FAVORING AREAS SOUTH OF
I-70.

WEDNESDAY...MONSOONAL MOISTURE CONTINUES TO OOZE NORTHWARD FROM
ARIZONA. SOME FORCING IS SEEN IN THE AFTERNOON WITH A 300MB POT
VORT LOBE LAYING OVER ACROSS THE NORTH. THIS COULD PROVIDE A FOCUS
FOR ENHANCED AFTERNOON CONVECTION. ISOLATED TO SCATTERED STORMS
WILL CONTINUE THROUGH WEDNESDAY NIGHT. VERY SLOW STORM
MOTION...NEAR ZERO IN THE FOUR CORNERS AREA...WILL COMBINE WITH
PWAT VALUES AT 1.1 INCH OR MORE ACROSS THE SOUTH. STORMS WILL NOT
BE WELL ORGANIZED WITH LITTLE SHEAR TO SEPARATE THE UPDRAFT-
DOWNDRAFT. BUT ANY GOOD CELL MAY PRODUCE HEAVY RAIN AND THIS
RAISES FLASH FLOODING CONCERNS FOR AREAS SOUTH OF I-70 AND WEST OF
GLENWOOD SPRINGS. AFTERNOON TEMPERATURES WILL BE MODIFIED DOWN TO
NEAR NORMAL UNDER CLOUDS AND SHOWERS.

THANK YOU TO SLC...FGZ...ABQ...PUB OFFICES FOR COORDINATION ON
THIS FIRST DEEP SURGE OF MONSOONAL MOISTURE INTO THIS FORECAST
AREA.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 342 PM MDT TUE JUL 8 2014

THE WAVE PASSING THROUGH THE NORTHERN PLAINS WILL DEFORM THE
NORTHERN EXTENSION OF THE SUB TROPICAL HIGH WHILE FORCING THE CENTER
OF THE CIRCULATION INTO NORTHEAST NEW MEXICO. THIS APPEARS TO LEAVE
A MORE DIRECT PATHWAY FOR MONSOONAL MOISTURE TO WRAP INTO OUR CWA.
TIME SERIES OF PWAT AND 315K MIXING RATIOS SHOW THE BETTER TAP OF
MOISTURE REMAINING IN PLACE THROUGH FRIDAY BEFORE ANOTHER WAVE
ROTATING AROUND THE RING OF FIRE DISRUPTS THE SOUTHERN MOISTURE
SOURCE. SO THE TREND OF AFTERNOON AND EVENING THUNDERSTORMS
CONTINUES THROUGH THE LATE WEEK PERIOD WITH HEATING...MOISTURE AND
BOUNDARY INTERACTION DRIVING THE CONVECTION. LARGE SCALE ASCENT AND
JET DYNAMICS ARE LACKING LEAVING SHEAR ON THE LIGHT SIDE. STRONG
STORMS MAY NOT BE LIKELY BUT WILL BE SLOW MOVING. THIS ALONG WITH
BOUNDARY INTERACTIONS AND OROGRAPHIC INFLUENCES WILL LEAVE THE FLASH
FLOOD THREAT IN PLACE THROUGH THURSDAY EVENING. THE PASSING WAVE ON
FRIDAY BRINGS A BIT MORE SHEAR FOR MORE ORGANIZED STORMS...BUT
DRYING AT THE LOW LEVELS BEGINS TO AFFECT THE DEPTH FOR WARM CLOUD
RAIN PROCESSES TO BE EFFECTIVE. HOWEVER PWAT REMAINS HIGH SO
THE FLASH FLOOD WATCH EXTENDS INTO FRIDAY.

GOING INTO THE WEEKEND AND BEYOND THE CRYSTAL BALL IS NOT QUITE SO
CLEAR. A ANOMALOUSLY STRONG LOW PRESSURE SYSTEM WILL BE MOVING
ACROSS THE GREAT LAKES REGION WHICH SHOULD FORCE THE SUBTROPICAL
HIGH BACK TO THE WEST. THE GLOBAL MODELS ARE SIMILAR IN HANDLING
THIS FEATURE BUT ARE NOT SO CONGENIAL WITH EACH OTHER WITH RESPECT
TO ANOTHER TROUGH MOVING INTO THE WEST COAST AND IT/S INTERACTION
WITH THE HIGH BY EARLY NEXT WEEK. WITH THIS DISAGREEMENT THERE IS A
BIG DISCREPANCY WITH WHERE THE MONSOONAL PLUME IS DIRECTED.
EITHER WAY MOISTURE WILL BE RECIRCULATED UNDER THE HIGH AND DAILY
AFTERNOON THUNDERSTORMS WILL PERSIST. IT IS THE COVERAGE AND
THREATS WITH THESE STORMS THAT IS UNCERTAIN. OVERALL TEMPERATURES
LOOK TO REMAIN AT OR SLIGHTLY ABOVE NORMAL THROUGH THE EXTENDED
PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 342 PM MDT TUE JUL 8 2014

THIS EVENING...STORMS WILL MOSTLY REMAIN MAINLY OVER THE SOUTHERN
AND CENTRAL MOUNTAINS. GUSTY OUTFLOW WINDS WILL BE MORE WIDESPREAD
INTO THE SOUTHERN AND CENTRAL VALLEYS THROUGH THE EVENING. WIND
GUSTS OF 30 TO 40 MPH THREATEN KDRO KTEX KCNY KMTJ KGJT UNTIL
06Z. BRIEF HEAVY RAIN WILL BE CONFINED TO THE MTNS INCLUDING
KTEX. AFTER MIDNIGHT ONLY ISOLATED CIRCUMNAVIGABLE STORMS ARE
EXPECTED FAVORING THE SOUTHERN AREAS.

OTHERWISE HIGH PRESSURE CENTERED OVER THE GREAT BASIN WILL SLOWLY
SHIFT EAST THROUGH WEDNESDAY. THIS WILL ALLOW DEEPER MOISTURE FROM
THE SOUTHWEST TO WORK OVER THE REGION WEDNESDAY AND WEDNESDAY
NIGHT. THIS WILL DRIVE MORE ACTIVE SHOWERS AND THUNDERSTORMS AFTER
18Z WEDNESDAY MAINLY SOUTH OF THE INTERSTATE 70 CORRIDOR.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH FRIDAY
     EVENING FOR COZ006-007-009-011-017>023.

UT...FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH FRIDAY
     EVENING FOR UTZ022-027>029.

&&

$$

SHORT TERM...JOE
LONG TERM...15
AVIATION...JOE


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