Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 301846
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1246 PM MDT THU JUL 30 2015

.UPDATE...
ISSUED AT 1242 PM MDT THU JUL 30 2015

SHOWERS AND TSTORMS OVER THE FOUR CORNERS REGION VERY SLOW TO
DEVELOP SO FAR TODAY. VIS SATELLITE BARELY SHOWS ANY CUMULUS AS OF
1230 PM...SO PUSHED BACK AND DECREASED PRECIP COVERAGE FOR THE
FOUR CORNERS REGION TODAY AND TONIGHT. SPC MESOANALYSIS KEEPING
DEEPER MOISTURE SOUTH OF THE UTAH/COLORADO BORDER FOR NOW TOO. SHORT
TERM FORECAST MODELS HAVE PICKED UP THIS LACK OF PRECIPITATION.
THAT BEING SAID INCREASING CLOUD TOPS IN THE MOUNTAINS WILL LIKELY
SPUR SOME ISOLATED CONVECTION WITH SOME 25 MPH GUSTS AND MODERATE
PRECIP BY LATER THIS AFTERNOON IN THE HEAVIER SHOWERS.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 348 AM MDT THU JUL 30 2015

THE SUBTROPICAL RIDGE THAT WAS CENTERED OVER NORTH TEXAS ON
WEDNESDAY CONTINUES TO AMPLIFY INTO COLORADO TODAY. THE WEST TO
EAST RIDGE AXIS IS ORIENTED ROUGHLY ALONG HIGHWAY 50. DEEP
MONSOONAL MOISTURE WILL CONTINUE TO INVADE SOUTH OF THE RIDGE
AXIS TODAY AND TONIGHT. THE SW CO VALLEYS AND SW SAN JUANS WILL
SEE SCATTERED SHOWERS AND ISOLATED STORMS FORMING THROUGH THE
MORNING. BY AFTERNOON THUNDERSTORM COVERAGE INCREASES. STORM
MOTION WILL BE VERY SLOW...EVEN STATIONARY THIS AFTERNOON AND
EVENING. PRECIPITABLE WATER VALUES CLIMB TO OVER 1.3 INCHES IN THE
FOUR CORNERS BY LATE AFTERNOON. THIS THREATENS LOCALLY HEAVY
RAINFALL MAINLY FROM RED MTN PASS TO SLUMGULLION PASS SOUTHWARD.
NORTH OF HIGHWAY 50 HOT AND DRY CONDITIONS WILL CONTINUE ADDING A
FEW DEGREES TO THE AFTERNOON HIGH TEMPERATURES. WIDESPREAD SHOWERS
OVER THE SAN JUANS CAN OFTEN PRODUCE GUSTY WINDS INTO THE WEST
CENTRAL VALLEY INCLUDING THE I-70 CORRIDOR. BUT LIGHT WEST
GRADIENT WINDS ALOFT MAY LIMIT THESE STRONGER WINDS. SOUTHERN
SHOWERS AND STORMS ARE EXPECTED TO CONTINUE THROUGH THE TONIGHT.

FRIDAY THE MOISTURE ACROSS THE SOUTHERN ZONES DIMINISHES SOMEWHAT.
SO STORM COVERAGE MAY ALSO SHRINK SOMEWHAT. ISOLATED TO SCATTERED
AFTERNOON STORMS MAY FORM UP TO THE I-70 CORRIDOR. HOT AND DRY
CONTINUES OVER THE NORTHERN HALF OF THE FORECAST AREA.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 348 AM MDT THU JUL 30 2015

STABLE LONG WAVE PATTERN WITH HIGH PRESSURE CENTERED OVER THE SWRN
CONUS WILL PREVAIL THROUGH THE LONG TERM PERIOD. MONSOONAL
MOISTURE WILL CIRCULATE AROUND THE HIGH CENTER...DIURNAL HEATING
AND PERIODIC DISTURBANCES WILL BE THE PRIMARY MECHANISMS FOR
SHOWERS AND THUNDERSTORMS. THE DEEPEST MOISTURE COVERS THE
SOUTHERN HALF AND THIS AREA STANDS THE BEST CHANCE OF
SHOWERS/STORMS EACH DAY.

THE GFS AND ECMWF DO INDICATE AN EMBEDDED DISTURBANCE IN THE LIGHT
FLOW PATTERN THAT SHOULD ENHANCE SHOWERS/STORMS ACROSS UTAH AND
COLORADO. NEITHER AGREE ON THE EXACT DAY (EITHER SUNDAY OR MONDAY)
NOR INTENSITY. WILL SEE HOW THIS EVOLVES AND BOOST POPS WHEN
CONFIDENCE RISES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1107 AM MDT THU JUL 30 2015

MOSTLY CLEAR CONDITIONS ARE EXPECTED NORTH OF THE SAN JUANS AND
FROM KCNY NORTH. SCATTERED SHOWERS ARE EXPECTED TO DEVELOP THIS
AFTERNOON OVER THE SAN JUANS AND THE FOUR CORNERS VALLEYS. THERE
IS ABOUT A 10% CHANCE THAT ILS BREAKPOINTS COULD BE REACHED IF A
HEAVY THUNDERSTORM PASSES OVER KTEX AND KDRO THIS AFTERNOON OR
EVENING. ISO SHOWERS AND TSTORMS MAY POTENTIALLY CONTINUE THROUGH
18Z FRIDAY ACROSS THE FOUR CORNERS REGION. NO MAJOR WIND THREATS
ARE EXPECTED OVER THE NEXT 24 HOURS.


&&

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

$$

UPDATE...JAM
SHORT TERM...JOE
LONG TERM...PF
AVIATION...JAM


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