Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 230008
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
608 PM MDT FRI MAY 22 2015

.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 359 PM MDT FRI MAY 22 2015

SHOWERS AND THUNDERSTORMS DEVELOPED IN THE CLEAR AIR BEHIND THE
SHORT WAVE TROUGH WHICH PASSED OVER THE AREA LAST NIGHT AND INTO
THE MORNING. THERE WAS IN FACT...ENOUGH LOW-LEVEL WIND SHEAR AND
UPPER LEVEL SUPPORT TO GENERATE A SHORT-LIVED SEVERE THUNDERSTORM
OVER THE GRAND JUNCTION AREA EARLY THIS AFTERNOON. DAYTIME HEATING
COMBINED WITH DIFFLUENCE/DIVERGENCE ALOFT AHEAD OF AN APPROACHING
LOW TO THE SOUTHWEST WILL CONTINUE TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS...MORE NUMEROUS OVER HIGHER TERRAIN...DURING THE
REMAINDER OF THE AFTERNOON THROUGH SUNSET.

THE LOW PRESSURE SYSTEM MENTIONED PREVIOUSLY WILL MOVE FROM
NORTHWEST ARIZONA TO SOUTHEAST UTAH DURING THE NIGHT. LIFT AHEAD
OF THE SYSTEM WILL SUSTAIN NOCTURNAL SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS DURING THE REMAINDER OF THE NIGHT. HOWEVER...
ADVECTION OF DRIER AIR DROPS PRECIPITABLE WATER VALUES FROM NEAR
0.60 OF AN INCH RECORDED IN THE MORNING SOUNDING TO AROUND 0.40
OF AN INCH DURING LATE AFTERNOON AND EVENING. DRYING COMBINED WITH
DIURNAL COOLING WILL REDUCE SHOWER COVERAGE. ELEVATIONS AT OR
ABOVE 9000 FEET WILL SEE ADDITIONAL SNOW...BUT ACCUMULATIONS WILL
BE LIGHTER AND MORE SPOTTY IN COVERAGE SO DO NOT PLAN TO ISSUE
WINTER WEATHER ADVISORIES WITH THIS PACKAGE. BEAR IN MIND...
HOWEVER...THAT MOUNTAIN PASSES MAY HAVE SOME LIGHT ACCUMULATIONS
WHICH COULD SLOW TRAVEL. EXPECT OVERNIGHT LOWS TO BE NEAR THOSE
RECORDED LAST NIGHT WHICH WERE CLOSE TO NORMAL FOR THE TIME OF
YEAR.

THE UPPER LOW WILL BE AT OUR DOORSTEP IN SOUTHEAST UTAH TOMORROW
MORNING AND TREK NORTHEAST TOWARD SOUTHEAST WYOMING BY SUNDAY
MORNING. STRONG ASCENT FROM THE CYCLONIC JET ROUNDING THE BASE OF
THE LOW WILL RESIDE OVER OUR SOUTHERN CWA TOMORROW MORNING THEN
SHIFT THROUGH THE DAY AS THE STORM PROGRESSES TO THE NORTH. A DRY
SLOT RESPONSIBLE FOR DROPPING PWATS AS MENTIONED ABOVE LOOKS TO KEEP
POPS SOMEWHAT ON THE LOW END EVEN THOUGH THE LIFT IS STRONG
OVERHEAD. HOWEVER BY AFTERNOON ANOTHER LOBE OF ENERGY AND WRAP
AROUND MOISTURE WILL ALLOW SHOWERS AND THUNDERSTORMS TO BLOSSOM AND
UNFORTUNATELY WE ARE IN FOR ANOTHER COOL AND WET WEEKEND.
TEMPERATURES WILL BE WARM ENOUGH TO LIFT ACCUMULATING SNOW BACK TO
THE HIGH PEAKS BY MID MORNING. FOR SUNDAY NIGHT QG PROGS INDICATE
REALLY TWO AREAS OF FOCUSED LIFT...THE NORTHERN COLORADO MOUNTAINS
AND NEAR THE 4 CORNERS AS A WAVE DROPS INTO THE BACK OF THE LOW.
CONDITIONS LOOK FAVORABLE FOR SNOW TO DEVELOP OVERNIGHT IN THE HIGH
COUNTRY SIMILAR TO THE PAST FEW DAYS. CONFIDENCE HOWEVER IS NOT
STRONG THAT IMPACTS WILL BE WIDESPREAD ACROSS OUR CWA AND HAVE HELD
OFF ON WINTER HIGHLIGHTS AT THIS TIME.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 359 PM MDT FRI MAY 22 2015

FOR THE UPCOMING WEEK THE UPPER LATITUDES LOOK TO REMAIN IN A
BLOCKY PATTERN WITH A PERSISTENT RIDGE OVER WESTERN CANADA
ALLOWING PACIFIC ENERGY TO FREELY ENTER THE LOWER 48. THE TREND
FOR LATE THE WEEK IS TO FINALLY BUILD A LARGER RIDGE ACROSS ALL OF
WESTERN NOAM BUT SINCE THIS IS HIGH ANOMALOUS RIGHT NOW WILL NEED
TO WAIT IT OUT. THE UPPER LOW IN THE HIGH PLAINS WILL CONTINUE TO
ROTATE NORTHWARD INTO THE WESTERN DAKOTAS ON SUNDAY AS HIGH
PRESSURE IS TOO STRONG OVER THE EASTERN STATES. THE LAST BIT OF
ENERGY SHEARING FROM THIS CYCLONE AND RESIDUAL MOISTURE WILL KEEP
SHOWERS AND THUNDERSTORMS IN THE PICTURE FOR SUNDAY AFTERNOON
THOUGH THERE SHOULD BE A SLIGHT DOWNTURN IN COVERAGE. WITH THE
NEXT PIECE OF UPSTREAM ENERGY SWINGING SOUTH OF OUR CWA SUNDAY
NIGHT INTO MONDAY A MORE NOTICEABLE DOWNTURN IN CONVECTION SHOULD
BE FELT FOR THE MONDAY AND SOME PART OF THIS HOLIDAY MAY BE
SALVAGED WITH TEMPERATURES ALSO BEGINNING AND TREND UPWARDS.
UNSETTLED CONDITIONS WILL STAY IN PLACE THROUGH THE WEEK AS
AFTERNOON INSTABILITY AND MOISTURE WILL BE ENOUGH TO PRODUCE AT
LEAST DIURNALLY DRIVEN STORMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 604 PM MDT FRI MAY 22 2015

SHOWERS AND STORMS CONTINUE THIS EVENING WITH IFR CIGS AND VIS
OCCURRING AT SEVERAL TAF SITES. WINDS ALSO ENTERING THE EQUATION
WITH WIND GUSTS OF 30 TO 40 MPH BEING REPORTED ACROSS MUCH OF THE
FORECAST AREA. CONVECTION WILL CONTINUE THROUGH 04Z BEFORE
QUIETING DOWN THOUGH SOME SHOWERS AND AN OCCASIONAL RUMBLE OF
THUNDER WILL LIKELY CONTINUE PAST 06Z. EXPECT A REPEAT PERFORMANCE
TOMORROW STARTING AFTER 18Z THOUGH COVERAGE SHOULD BE SOMEWHAT
LESS. LIKE TODAY...MAIN CONCERN WILL BE LOW CIGS/VIS AND GUSTY
OUTFLOW WINDS FROM ANY CONVECTION THAT FORMS.

&&

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

$$

SHORT TERM...NL/15
LONG TERM...15
AVIATION...TGR


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