Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 200942
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
342 AM MDT WED MAY 20 2015

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 339 AM MDT WED MAY 20 2015

HEIGHTS WILL BE ON THE RISE TODAY AS THE OLD UPPER LOW CONTINUES
TO LIFT OUT INTO THE PLAINS. SOME MOISTURE LINGERS EARLY IN THE
DAY TO KEEP A FEW SHOWERS GOING ACROSS THE NORTHERN ZONES...MAINLY
ANCHORED UP AGAINST THE PARK RANGE. WITH THE RISING HEIGHTS WILL
ALSO COME RISING TEMPERATURES AND SFC READINGS WILL BE JUMPING 5
TO 10 DEGREES IN MOST AREAS...BUT STILL A TAD BIT BELOW NORMAL FOR
THIS TIME OF YEAR. CONVECTIVE TEMPS WILL BE REALIZED OVER THE HIGH
COUNTRY BY EARLY AFTERNOON AND THIS WILL WORK ON LINGERING LOW
LEVEL MOISTURE TO INCREASE COVERAGE OF THE MORNING
SHOWERS...ALTHOUGH THE FOCUS WILL BE OVER THE HIGH COUNTRY WITH
WEAK STEERING FLOW FAILING TO DRIVE THEM OFF THE HILLS AND OVER
THE VALLEYS.

THE DIURNALLY DRIVEN SHOWERS DIMINISH EARLY THIS EVENING WITH DRY
CONDITIONS EXPECTED OVERNIGHT AS THE RIDGE AXIS SLIDES EAST OF THE
DIVIDE.

BY THURSDAY...FLOW IS BACKING BACK AROUND TO THE SOUTH SOUTHWEST
AS YET ANOTHER LOW DIGS ALONG THE CALIFORNIA COAST. MODELS DRIVE
MORE MOISTURE NORTH NORTHWEST ACROSS WEST TEXAS AND EASTERN NEW
MEXICO UP INTO OUR FORECAST AREA BY THURSDAY AFTERNOON.
PRECIPITABLE WATER VALUES JUMP BACK TO OVER A HALF AN INCH BY LATE
IN THE DAY. WITH MOISTURE RAPIDLY INCREASING AND SEVERAL WEAK
WAVES IN THE SOUTHERLY FLOW LIFTING NORTH...EXPECT AN INCREASE IN
SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON AND EVENING. BETTER
STORM MOTION TRANSLATES INTO STORMS ROLLING OVER THE VALLEYS BY
LATE IN THE DAY. STILL EXPECT PLENTY OF SUN EARLY ON WITH TEMPS
CLIMBING ANOTHER 5 DEGREES TO BRING THE REGION MORE IN LINE WITH
CLIMATOLOGY.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 AM MDT WED MAY 20 2015

MODELS CONTINUE TO AGREE THAT MOISTURE WILL BE STREAMING UP FROM
THE SUBTROPICS THANKS TO THE LOW OFF THE CALIFORNIA COAST AND HIGH
OFF THE GULF COAST. ATTM...THE SAN JUANS AND THE CONTINENTAL
DIVIDE LOOK TO GET THE MOST PRECIP. BY FRIDAY MORNING...SOME
DEFINITE TURNING OF THE WINDS AT THE 700MB LEVEL INDICATES A
SHORTWAVE MOVING ACROSS THE CWA CAUSING A MODERATE INCREASE IN
ACTIVITY. BY NOON...THE WAVE WILL HAVE LIFTED INTO WY BUT NOT MUCH
REPRIEVE IN PRECIP AS THE LOW PRESSURE CONTINUES MOVING EWRD WITH
MORE SHOWERY PRECIP FORECAST FOR THE HIGHER TERRAIN.

DIFFERENCES START ARISING SATURDAY WITH THE GFS LIFTING THE LOW
PRESSURE NORTHWARD FAIRLY QUICKLY WHILE THE EC KEEPS IT SOMEWHAT
STATIONARY OVER THE CWA. THE GFS CONTINUES TO SHOW A DRY SLOT
OVER THE AREA WHILE THE EC A BIT MORE AGGRESSIVE. THE CANADIAN
ALSO KEEPS US DRY AS DOES THE NAM TO A CERTAIN EXTENT. WHAT IS
CERTAIN WILL BE CLOUDS AND SHOWERY PRECIP WITH SOME AFTN
CONVECTION. THE TRICKY BIT IS HOW MUCH...HOW LONG...AND WHERE.
CHANCE TO SLIGHT CHANCE POPS STILL LOOK GOOD FOR NOW.

BY SUNDAY...ANOTHER DAY OF OFF AND ON SHOWERS AS THE NEXT LOW
PRESSURE QUICKLY DROPS DOWN FROM THE PACNW. A DEFORMATION AXIS
LOOKS TO SET UP OVER UTAH AND COLORADO AND LOOKS TO BE THE FOCUS
OF PRECIP AHEAD OF THE LOW PRESSURE SUNDAY AFTERNOON INTO THE
OVERNIGHT HOURS. AMPLE MOISTURE AND WIDESCALE LIFT THANKS TO THE
LOW PRESSURE WILL BRING EVEN MORE PRECIP MONDAY THROUGH TUESDAY.
WE HAD A DRY WINTER...BUT THIS SPRING IS REALLY MAKING UP FOR IT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 339 AM MDT WED MAY 20 2015

SOME CLOUDS LINGER THIS MORNING BUT ASIDE FROM THE GUNNISON
BASIN...VFR CONDITIONS ARE IN PLACE. MORE CONVECTION AND SHOWERS
EXPECTED AFTER 18Z WITH HIGHER ELEVATIONS BEING FAVORED. MOST
AREAS WILL REMAIN VFR THOUGH SOME MVFR TO BRIEF IFR POSSIBLE UNDER
AND NEAR THE STRONGER CELLS. SOME MTN TOPS WILL BE OBSCURED
ESPECIALLY THOSE ALONG THE CONTINENTAL DIVIDE.

&&

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

$$

SHORT TERM...JDC
LONG TERM...TGR
AVIATION...TGR


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