Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KGJT 181652
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1052 AM MDT SAT OCT 18 2014

.UPDATE...
ISSUED AT 1050 AM MDT SAT OCT 18 2014

SATELLITE LOOP SHOWED AN UPPER LOW MOVING INTO NERN NM THIS
MORNING WHILE A PACIFIC TROUGH WAS IN THE PROCESS OF SPLITTING AS
IT APPROACHES THE WESTERN GREAT BASIN. RATHER EXTENSIVE MID-LEVEL
CLOUD DECK ACROSS ERN UT/SWRN CO APPEARS ASSOCIATED WITH A SMALL
SHORTWAVE MOVING INTO SERN UT PER 500 MB VORTICITY FIELD. HI-
RESOLUTION MODELS CONTINUE TO FOCUS SOME PRECIPITATION ON THE SAN
JUAN MTNS THIS AFTERNOON...WHERE 16Z SPC MESOANALYSIS SHOWED LOW
LEVEL LAPSE RATES STEEPENING THE QUICKEST. CURRENT FORECAST HAS
THIS IN HAND. WILL TWEAK THE FORECAST SKY GRIDS TO BOOST CLOUD
COVER ACROSS THE CENTRAL PORTION THIS AFTERNOON.

&&

.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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1050 AM MDT SAT OCT 18 2014

AN UPPER LOW MOVING ACROSS NRN NM AND A PACIFIC TROUGH MOVING INTO
THE WESTERN GREAT BASIN WILL RESULT IN A FAIRLY EXTENSIVE MID-LEVEL
CLOUD DECK ACROSS ERN UT AND THE SRN TWO-THIRDS OF WRN CO THROUGH
THIS EVENING. WEAK INSTABILITY SHOULD LEAD TO ISOLD-SCT SHOWERS
MAINLY OVER THE SAN JUAN MTNS BUT A FEW COULD REACH AS FAR NORTH AS
GRAND MESA AND THE ELK MTNS. ISOLD TS POSSIBLE OVER THE SAN JUANS
THIS AFTERNOON. ACTIVITY SHOULD DIMINISH BY 06Z TONIGHT.

&&

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

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.