Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 180854
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
254 AM MDT SAT OCT 18 2014

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 253 AM MDT SAT OCT 18 2014

IR SATELLITE SHOWING PLENTY OF CLOUDS FOR MAINLY SOUTHERN AREAS OF
THE CWA THIS MORNING WITH SOME LIGHT RETURNS SHOWING UP ON RADAR.
THESE CLOUDS ARE IN RESPONSE TO A WEAK WAVE THAT IS CURRENTLY
MOVING ACROSS CO AND NEW MEXICO. BY DAYBREAK THE WAVE WILL SHIFT
TO ERN CO WHILE ANOTHER WEAK WAVE TAKES AIM FOR AREAS SOUTH. HRRR
AND RAP NOT SHOWING MUCH PRECIP UNTIL THIS AFTN WITH NAM12
FOLLOWING SUIT. KEPT VERY ISOLD POPS OVER HIGHEST ELEVATIONS OF
SAN JUANS WITH COVERAGE INCREASING THROUGH THE DAY REACHING THE
CENTRAL MOUNTAINS FROM NOON ONWARDS. LAPSE RATES STEEPEN SOMEWHAT
THIS AFTERNOON WITH CONDITIONAL INSTABILITY ALSO INCREASING A BIT
SO INCLUDED ISOLD STORMS THOUGH THEY SHOULD BE FEW AND FAR
BETWEEN. THOSE AREAS AWAY FROM ANY CONVECTION WILL SEE SOME MID TO
HIGH CLOUDS AS TEMPS CONTINUE TO RUN WARM.

A PSEUDO-REX BLOCK WILL BE SETTING UP TONIGHT INTO SUNDAY WITH
THE LOW OVER THE BAJA REGION TRAPPED UNDER AN AMPLIFYING NORTHERN
ROCKIES RIDGE. THIS RIDGE WILL DOMINATE THE NORTH CENTRAL STATES
THROUGH THE WEEKEND AS STRONG LOW PRESSURE SETTLES OVER THE LEFT
AND RIGHT COASTLINES OF NOAM. A SLIGHT NEGATIVE TILT TO THE
SOUTHERN FLOW PATTERN OVER THE DESERT SOUTHWEST APPEARS TO TAP
INTO MOISTURE ORIGINATING IN THE WESTERN GULF OF MEXICO. 305K
THETA SURFACES SHOW A DECENT WARM CONVEYOR BELT ASCENDING OUT OF
WEST TEXAS TOWARD THE 4 CORNERS OVER THE NEXT 48 HOURS. THE BULK
OF THE MOISTURE WILL BE UTILIZED TO OUR SOUTH WHERE THE MAIN
SOURCE OF ASCENT WILL BE PRESENT. FARTHER NORTH...OROGRAPHICS AND
MARGINAL CONDITIONAL INSTABILITY WILL BE KEEPING SHOWERS AND
ISOLATED THUNDERSTORMS FOCUSED OVER OUR SOUTHERN MOUNTAINS. A
STRAY SHOWER MAY SURVIVE INTO THE VALLEY BUT UPPER WINDS ARE NOT
ENTIRELY FAVORABLE. TEMPERATURES WILL BE STUCK IN A RUT AND
PERSISTENCE STILL SEEMS THE WAY TO GO.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 253 AM MDT SAT OCT 18 2014

A STRONGER POLAR JET WILL BE DESCENDING THE HIGH LATITUDES TOWARD
THE NORTHWEST STATES SUNDAY NIGHT INTO MONDAY. THIS FORCES THE REX
PATTERN EVER SO SLOWLY TO THE EAST AS STRONG BLOCKING PERSISTS IN
THE EAST. FORCING REMAIN MINIMAL AND SO LOW POPS STUCK TO THE
TERRAIN IN THE CENTRAL AND SOUTHERN COLORADO MOUNTAINS HIGHLIGHT
THE FORECAST AS TEMPERATURE TRENDS REMAIN STATIC.

UPPER LEVEL SUPPORT WILL BE LIFTING OUT OF OUR REGION TUESDAY AND
AS IT DOES SO...WEAKENING DIVERGENCE WILL LEND ITSELF TO SOME SPOTTY
PRECIP FOR MAINLY HIGHER ELEVATIONS OF THE CWA. QUICK ON THE
HEELS OF THIS WAVE IS A STRONG JET THAT WILL PROVIDE SUPPORT FOR
ANOTHER DISTURBANCE AND MORE PRECIP WEDNESDAY INTO WEDNESDAY
NIGHT. MODELS NOT SHOWING MUCH OF A BREAK BETWEEN THESE TWO WAVES
SO EXPECT UNSETTLED WX FOR MOST OF TUESDAY AND WEDNESDAY. AFTER
THAT...HIGH PRESSURE BUILDS IN AND PERSISTS THROUGH THE END OF
THE PERIOD. DRY WEATHER WILL BE THE RESULT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 253 AM MDT SAT OCT 18 2014

CLOUDS CONTINUE TO STREAM INTO THE AREA THIS MORNING WITH MID
LEVEL CLOUDS BEING REPORTED IN THE SAN JUANS AND AREAS SOUTH.
SHOWERS ARE EXPECTED FOR THE SAME AREA FROM 12Z ONWARDS
OVERSPREADING TO THE CENTRAL MTNS BY 18Z. SOME STORMS ARE POSSIBLE
THIS AFTN BUT EXPECT COVERAGE TO BE VERY ISOLATED IN
NATURE...FAVORING THE HIGHEST TERRAIN. LOW CONFIDENCE THAT ANY TAF
SITES WILL BE AFFECTED SO WILL LEAVE OUT ANY MENTION FOR NOW. SOME
LINGERING SHOWERS MAY PERSIST PAST 03Z BUT VERY LIMITED COVERAGE
EXPECTED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

$$

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



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