148
FXUS65 KGJT 161409
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
809 AM MDT WED OCT 16 2013
.UPDATE...
ISSUED AT 802 AM MDT WED OCT 16 2013
RECORD LOW TEMPERATURE SET IN GRAND JUNCTION THIS MORNING AS SKIES
CLEARED AND WINDS DROPPED OFF BEHIND THE EXITING SHRTWV. THE COLD
TEMPERATURES WILL BE CLIMBING BACK ABOVE FREEZING OVER THE NEXT
HOUR AND HAVE ALLOWED THE FREEZE WARNING TO EXPIRE. HAVE ALSO
DROPPED THE WINTER WEATHER ADVISORY AS MORNING WEBCAMS...RADAR AND
SFC REPORTS ALL POINT TO DIMINISHED ACTIVITY. SNOTELS HAVE ALSO
FLAT LINED IN MOST AREAS. TOTAL SNOWFALL AMOUNTS OVERNIGHT ACROSS
VARIED FROM A TRACE TO 4 INCHES...WITH THE GREATEST AMOUNTS
GENERALLY EAST OF HIGHWAY 550 AND SOUTH OF HIGHWAY 50. WILL BE
UPDATING THE ZONES SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 252 AM MDT WED OCT 16 2013
IR IMAGERY SHOWING SOME ENHANCEMENT OVER THE SAN JUANS THIS
MORNING WITH PAGOSA SPRINGS...WOLF CREEK AND MONARCH PASSES ALL
REPORTING SNOWFALL TOO. HOWEVER...PRECIP SHOULD START SHIFTING
EWRD AS THE TROUGH CONTINUES TO DROP TO THE SE THANKS TO THE JET
STREAM ALSO LIFTING OUT OF OUR CWA. SNOW SHOULD SLOWLY START
COMING TO AN END BY DAYBREAK AND EXPECT ADVISORIES WILL BE ABLE TO
COME DOWN EARLY. AFTER THAT...EXPECT PARTLY TO MOSTLY SUNNY SKIES
WITH HIGHS RUNNING ANYWHERE FROM 10 TO 15 DEGREES BELOW NORMAL.
EXPECT MORE CLOUDS OVER HIGHER TERRAIN THAN VALLEYS.
THE FREEZE WARNING REMAINS IN EFFECT FOR THE GRAND VALLEY AND MOAB
AREAS THOUGH WITH DEWPTS HOVERING AROUND 31F...WILL BE A CLOSE
CALL IF WE HIT FREEZING OR NOT.
FOR TONIGHT AND THURSDAY...THE HIGHLY AMPLIFIED RIDGE TO THE WEST
WILL SLOWLY PROGRESS TO THE WESTERN COASTLINE. THIS IS DUE TO THE
UPSTREAM TROF OVER THE ALEUTIANS ABSORBING THE REMNANTS OF THE
TYPHOON MOVING NEAR JAPAN WHILE THE DOWNSTREAM TROF DIGS SOUTHWARD
THROUGH THE CANADIAN PRAIRIES BY THE STRONG PACIFIC JET OVER
TOPPING THE ALASKAN RIDGE. THIS ARRIVAL OF THE JET AND TROF TO THE
NORTHERN US HIGH PLAINS THIS EVENING WILL CONTINUE TO DRIVE THE
CURRENT TROF OVER OUR CWA INTO THE EASTERN PLAINS. SKIES WILL BE
CLEARING IN THE EAST IN THE WAKE OF THIS SYSTEM AS HIGH CLOUDS
APPROACH FROM THE WEST...AHEAD OF THE JET AND ENERGY TO THE NORTH.
HIGH PRESSURE WILL BE SETTLING OVER THE REGION AND EXPECT ANOTHER
CHILLY NIGHT. WATER VAPOR SHOWS SOME MOISTURE PUSHING INTO THE
PATH OF THIS NEXT TROF WHICH WILL BE SWINGING THROUGH NORTHEAST
UTAH BY MIDNIGHT AND TO THE DIVIDE BY SUNRISE. FORCING NOT NEARLY
AS STRONG AS THE PAST FEW SYSTEM AND IT WILL BE MOVING THROUGH
QUICKLY. EXPECT FLURRIES OR VERY LIGHT LIGHT SNOW WILL BE POSSIBLE
OVER THE HIGHEST TERRAIN OF NORTHEAST UTAH AND NORTHERN COLORADO
OVERNIGHT THROUGH LATE MORNING BUT ACCUMULATION SHOULD BE MINIMAL.
AS THE ATMOSPHERE DESTABILIZED IN THE AFTERNOON BY COLDER AIR
MOVING IN ALOFT...THE SHOWERS WILL BECOME MORE SCATTERED ACROSS
OUR NORTHERN MOUNTAINS WITH SNOW LEVELS POSSIBLY DROPPING DOWN TO
NEAR 8000 FEET. CLOUDS WILL HAMPER TEMPERATURES THE MOST IN THE
NORTH AND WENT NEAR THE LOWER END OF GUIDANCE THERE WITH HIGHS
STILL REMAINING SEASONALLY COOL FOR THE REMAINDER OF THE AREA AS
WELL.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 252 AM MDT WED OCT 16 2013
SLIGHTLY STRONGER FORCING...WEAKER STATIC STABILITY AND A PUSH OF
MOISTURE LOOKS TO BRING THE BEST CHANCES OF PRECIPITATION THURSDAY
EVENING AND EARLY FRIDAY TO OUR NORTHERN AND CENTRAL MOUNTAINS.
FORCING FOR ASCENT LOOKS TO BE COMBINED INTO A SECONDARY TROF AND
EXIT REGION OF THE JET OVER SOUTHERN WYOMING. NORTHWESTERLY
OROGRAPHICS ALONG WITH THE FORCING AND INSTABILITY SHOULD BRING
SOME BETTER SNOWFALL TO THE PARK...GORE AND POSSIBLY FLAT TOP
RANGES. A FRONT BACKED INTO THE FRONT RANGE MAY EVEN GET DEEP
ENOUGH TO HELP FOCUS SOME MOISTURE ALONG THE CENTRAL DIVIDE AS THE
TROF SWINGS THROUGH. SNOW AMOUNTS LOOKS TO BE 2-4 INCHES OVER THE
PASSES IN THE NORTH WITH HIGHER AMOUNTS ABOVE.
FOR FRIDAY AND BEYOND...HIGH PRESSURE WILL SET UP OVER THE ERN
PACIFIC WHILE A LARGE AMPLITUDE TROUGH REMAINS OVER THE EASTERN
U.S. THIS WILL KEEP NWRLY FLOW IN PLACE THROUGH THE ENTIRE PERIOD.
MODELS DO PICK UP ON SOME EMBEDDED WAVES MOVING THROUGH THIS FLOW
FROM TIME TO TIME THOUGH MOST WX LOOKS TO REMAIN OVER THE FRONT
RANGE WITH MAYBE A FEW SHOWERS OVER THE NRN MTNS. PLENTY OF SUN ON
TAP WITH WARM TEMPERATURES EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 252 AM MDT WED OCT 16 2013
IFR TO MVFR BEING REPORTED OVER THE SAN JUANS AT THIS HOUR BUT
EXPECT CONDITIONS TO IMPROVE AFTER 15Z OR SO AS THE DISTURBANCE
CAUSING THE PRECIP SHIFTS TO THE E. A RETURN TO VFR FOR THE
ENTIRE CWA IS EXPECTED AFTER 18Z THOUGH SOME MID LEVEL SCT TO
OCCNL BKN CLOUDS ARE POSSIBLE ALONG THE CONTINENTAL DIVIDE. A WEAK
DISTURBANCE WILL MOVE OVER THE AREA FROM THE NW TO SE AFTER 00Z
THIS EVENING WITH CIGS EXPECTED AROUND 10K OR SO.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...TGR/15/
LONG TERM...15/TGR
AVIATION...TGR