Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 031900
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
100 PM MDT MON AUG 3 2015

.UPDATE...
ISSUED AT 1255 PM MDT MON AUG 3 2015

ACROSS THE NORTHERN FORECAST AREA...STORMS DEVELOPED AS EXPECTED
FIRST IN MOFFAT COUNTY IN NW COLORADO JUST BEFORE NOON TODAY. THE
UPPER LOW OVER NORTHERN UTAH THIS MORNING LIFTS INTO SW WYOMING
THIS EVENING. THE JET REMAINS NW OF THIS FORECAST AREA. STILL A
DEFORMATION ZONE PERSISTS OVER NE UTAH THIS AFTERNOON WHERE THE
STRONGEST STORMS ARE EXPECTED. THE MAIN THREAT FROM THESE STORMS
WILL BE WIND AS STORM MOTION WILL BE TO THE NE AT 25KTS. ANY
SIGNIFICANT OUTFLOW WINDS COULD GUST TO OVER 50 MPH ACROSS NE UTAH
AND NW COLORADO THIS AFTERNOON. THE AIR MASS IS DRYING TODAY.
INITIALLY THE BEST DRYING OCCURS IN THE MID LEVELS WHICH WILL ADD
TO THE AFTERNOON INSTABILITY. STORMS SHOULD DIMINISH QUICKLY THIS
EVENING WITH THE LOSS OF UPPER SUPPORT AND DIMINISHING MOISTURE.

ELSEWHERE RELATIVELY COOL CONDITIONS ARE KEEPING CLOUD TOPS LOW
FOR LIGHT RAIN SHOWERS BUT NO LIGHTNING THROUGH THE MORNING.
ISOLATED THUNDERSTORMS ARE EXPECTED LATER THIS AFTERNOON.

UPDATE ISSUED AT 538 AM MDT MON AUG 3 2015

PATCHY FOG AS FORMED OVER PORTIONS OF LA PLATA AND ARCHULETA
COUNTIES. APPEARS TO BE SHALLOW AND DEPENDENT ON THE AMOUNT OF
CLOUDS OVERHEAD. KDRO BRIEFLY WENT DOWN TO 1/4SM BUT DID NOT LAST
LONG.  UPDATED GRIDS TO REFLECT PATCHY FOG FOR THIS AREA.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 355 AM MDT MON AUG 3 2015

THE FOCUS FOR HEAVY PRECIPITATION MOVES NORTH TODAY AS THE CENTER
OF THE CLOSED LOW MOVES TO NORTHERN UTAH. SHORT TERM MODELS
INDICATE SOME GOOD BOOMERS DEVELOPING AROUND NOON TODAY ACROSS NE
UTAH AND NW COLORADO. SHOWERS AND THUNDERSTORMS WILL BE NUMEROUS
IN COVERAGE ON MONDAY ACROSS NORTHEAST UTAH AND NORTHWEST
COLORADO...WITH THE FLASH FLOOD THREAT DECREASING AS THE
STORMINESS ENTERS A LESS FLASHY REGION OF THE COUNTRY. THE STRONG
WIND AND HAIL THREAT WILL INCREASE TODAY DUE TO A VEERING VERTICAL
PROFILE AND INCREASING SPEED SHEAR. THE DRIER AIR ON WATER VAPOR
SATELLITE THIS MORNING ALSO CAUSES CONCERN FOR SOME STRONG
THUNDERSTORMS AS MOISTURE IS STILL IN PLACE...DYNAMICAL FORCES
WILL BE PRESENT...AND UPPER JET SUPPORT INCREASES.

THIS WEATHER SYSTEM FINALLY MOVES OUT OF UTAH AND COLORADO TONIGHT
LEAVING SOME BREEZY CONDITIONS ACROSS THE WY/UT/CO BORDER. HIGH
PRESSURE AND DRIER AIR WILL QUICKLY BUILD IN EARLY TUESDAY AND
KEEP ISOLATED AFTERNOON STORM DEVELOPMENT MAINLY TO THE MOUNTAIN
TERRAIN ON TUESDAY. TEMPERATURES WILL REBOUND BACK TO NEAR NORMAL
ON TUESDAY AS SUNSHINE ABOUNDS.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 355 AM MDT MON AUG 3 2015

SUBTROPICAL HIGH PRESSURE WILL BE CENTERED OVER THE SWRN CONUS
WITH THE RIDGE AXIS ALONG THE UTAH/COLORADO BORDER...EFFECTIVELY
SHUTTING DOWN THE MONSOONAL MOISTURE TAP INTO THE FOUR CORNERS
REGION. A PACIFIC SHORT WAVE MOVES ACROSS THE CENTRAL ROCKIES
WEDNESDAY NIGHT OR THURSDAY MORNING...BUT HAS LIMITED MOISTURE
WITH THE BEST LIFT NORTH OF OUR FORECAST AREA (MAYBE A STORM OR
TWO OVER THE HIGH COUNTRY). SURFACE WINDS BECOME BREEZY WEDNESDAY
AFTERNOON.

FRIDAY THROUGH SUNDAY...THE HIGH PRESSURE CENTER SHIFTS TOWARD THE
SRN PLAINS AND THE MONSOONAL MOISTURE PLUME SURGES NORTH THROUGH
ARIZONA INTO UTAH. MID LEVEL MOISTURE REACHES THE FAR SOUTH BY
FRIDAY AFTERNOON...BUT THE DEEPER MOISTURE AND HIGHER PWAT VALUES
ARRIVE ON SATURDAY. MOISTURE SURGE WILL BE PHASED WITH AN EJECTING
SHORT WAVE FROM THE WEST COAST TROUGH. SATURDAY COULD BE AN ACTIVE
CONVECTIVE DAY WITH DEEP CONVECTION WITH SOME VERTICAL SHEAR.
DRIER AIR MAY FOLLOW THE SHORT WAVE ON SUNDAY AND STORM ACTIVITY
MAY BECOME LESS NUMEROUS.

WITH RESPECT TO TEMPS...MORE SUN MEANS WARMER TEMPS DURING MID
WEEK BUT AROUND SEASONAL NORMS. COOLING TREND OCCURS NEXT WEEKEND
AS MOISTURE/CLOUD COVER INCREASES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY NOON)
ISSUED AT 1255 PM MDT MON AUG 3 2015

NORTH OF THE I-70 CORRIDOR...THROUGH 03Z WIDESPREAD SHOWERS AND
STORMS. A FEW CELLS WILL BE STRONG WITH LOCAL OUTFLOW WIND GUSTS
TO 50KTS...AND HEAVY RAIN SHOWERS WITH SMALL HAIL. 03Z-06Z
SCATTERED TO ISOLATED STORMS AND SHOWERS WITH VFR CONDITIONS
DOMINATE THEREAFTER.

SOUTH OF THE I-70 CORRIDOR. ILS CIGS WILL BE COMMON FOR MOUNTAIN
TAF SITES. STORMS ARE EXPECTED TO DISSIPATE QUICKLY THIS EVENING
AFTER 02Z...WITH SKIES BECOMING MOSTLY CLEAR AFTER 06Z.

TUESDAY AFTERNOON...ISOLATED TO SCATTERED STORMS WILL FORM OVER
THE HIGHER TERRAIN MAINLY NEAR THE CONTINENTAL DIVIDE.


&&

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

$$

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



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