Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 021618 CCA
AFDGJT

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1018 AM MDT SAT MAY 2 2015

.UPDATE...
ISSUED AT 1018 AM MDT SAT MAY 2 2015

SHEAR AXIS CUTS ACROSS THE UINTA MOUNTAINS TO THE THE PARK
RANGE/ELKHEAD MOUNTAINS TODAY. SATELLITE VIS DATA SHOW A FAIR
AMOUNT OF ACCAS/CU FIELD OVER THE UTAH PANHANDLE AND UINTA
MOUNTAINS...AND THIS OBSERVATION IS ALIGNED QUITE WELL WITH THE
POSITIONING OF THE SHEAR AXIS. THIS IS THE AREA OF FOCUS FOR
SCATTERED SHOWERS/STORMS WITH THE FIRST STORMS EXPECTED TO FIRE
OVER THE UINTAS/TAVAPUTS PLATEAU AND TRACK EAST NORTHEAST.
BOUNDARY LAYER IS STILL RELATIVELY DRY...SO SHOWERS WILL NOT BE
GENERATING TOO MUCH RAINFALL...JUST A QUICK SHOWER BUT ACCOMPANIED
BY A FEW GUSTY ERRATIC WINDS.

THERE IS A SECONDARY AREA OF ACCAS OVER SE UTAH AND WRN SAN JUAN
MOUNTAINS. THIS ACCAS FIELD WILL EVOLVE INTO SCATTERED SHOWERS/STORMS
OVER THE ELK/WEST ELK/SAN JUAN MOUNTAINS. ONE OR TWO CELLS MAY
HOLD TOGETHER AND IMPACT MONTROSE AND GUNNISON WITH A BRIEF
SHOWER/STORM AND GUSTY WINDS.

FOR SOUTHEAST UTAH...THE ACCAS FIELD GETS REPLACED BY DRY AIR
OVER NORTH CENTRAL ARIZONA. PERHAPS A BRIEF STORM OVER THE LA
SAL/ABAJO MOUNTAINS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 406 AM MDT SAT MAY 2 2015

HIGH PRESSURE CENTERED OVER THE TEXAS PANHANDLE WILL KEEP RIDGING
IN PLACE FOR MUCH OF THE DESERT SW. SIMILAR CONDITIONS IN PLACE
LIKE YESTERDAY WITH THE ONLY DIFFERENCE BEING A SLIGHT DOWNTICK IN
AVAILABLE MOISTURE. HIGH LAPSE RATES WILL REMAIN INTACT THIS
AFTERNOON KEEPING INSTABILITY IN THE PICTURE...MEANING ANOTHER
ROUND OF CONVECTION AGAIN FAVORING HIGHER TERRAIN. H7 STEERING
FLOW WINDS REMAIN RATHER LIGHT SO CHANCES FOR ANY STORMS/SHOWERS
TO MAKE THEIR WAY INTO ANY VALLEYS REMAINS ON THE LOW SIDE. NO
REAL UPPER LEVEL SUPPORT SO EXPECT MOST PRECIP TO END SHORTLY
AFTER SUNSET THOUGH A FEW LINGERING SHOWERS MAY PERSIST TO
MIDNIGHT.

A TROUGH/CLOSED LOW OFF THE BAJA COAST WILL CONTINUE SLIDING
EASTWARD SATURDAY NIGHT/SUNDAY MORNING. AS IT DOES SO...THE
RIDGE WILL ALSO SHIFT EASTWARD AS A SHORTWAVE TAKES AIM AT OUR
CWA. WITH A LITTLE BETTER SUPPORT...CONVECTION WILL BE A BIT MORE
WIDESPREAD BUT THE GENERAL GIST OF FAVORING HIGHER TERRAIN IS
STILL THE NAME OF THE GAME. WARM TEMPS WILL CONTINUE THROUGH THE
PERIOD.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 406 AM MDT SAT MAY 2 2015

MODELS WERE IN FAIRLY GOOD AGREEMENT WITH THE UNSETTLED PATTERN
DESCRIBED ABOVE CONTINUING INTO NEXT WEEK. AS MENTIONED IN THE
SHORT TERM DISCUSSION...THE CLOSED LOW OFF THE COAST OF BAJA MOVES
INLAND AND WILL EVENTUALLY PASS OVER THE FORECAST TUESDAY NIGHT.
MOISTURE INCREMENTALLY INCREASES AHEAD OF THIS SYSTEM BRINGING AN
INCREASE IN CLOUD COVER WHILE INCREASING THE CHANCES FOR VALLEY
SHOWERS DURING THE AFTERNOON/EVENING TIMEFRAME. WITH SUNSHINE
BECOMING MORE LIMITED THROUGH MIDWEEK...AFTERNOON TEMPERATURES
WILL TREND DOWNWARD WHILE OVERNIGHT LOWS REMAIN STEADY.

TEMPERATURES COOL FURTHER LATER IN THE WEEK IN THE WAKE OF THE
TROUGH PASSAGE AND WILL REMAIN SEVERAL DEGREES BELOW NORMAL
THROUGH FRIDAY. DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS WILL BE
REDUCED AS DRIER AIR FROM THE DESERT SOUTHWEST FILTERS INTO THE
REGION AHEAD OF A DEEP TROUGH ALONG THE COAST WHICH WILL STAY PUT
THROUGH WEEKS END.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 406 AM MDT SAT MAY 2 2015

EXPECT VFR CONDITIONS AT AIRPORTS ACROSS THE REGION THROUGH THE
NEXT 24 HOURS. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE MOUNTAINS AFTER 18Z RESULTING IN SOME OBSCURATION OF
PEAKS AND RIDGES. THERE IS A SLIGHT CHANCE SHOWERS WILL MOVE OVER
ADJACENT AIRPORTS FROM 20Z TO 02Z/SUN. HOWEVER...THIS ACTIVITY IS
UNLIKELY TO DEGRADE CIGS OR VSBY BELOW VFR BUT WILL MORE LIKELY
TO GENERATE WIND GUSTS TO 35 MPH FOR A SHORT TIME. SHOWERS WILL
LARGELY DIMINISH AFTER 06Z/SUN.


&&

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

$$

UPDATE...PF
SHORT TERM...TGR
LONG TERM...NL
AVIATION...NL


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