000
FXUS65 KGJT 181702
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1102 AM MDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 1102 AM MDT SAT MAY 18 2013

THE UPPER TROUGH AXIS WAS OVER CENTRAL UTAH THIS MORNING AND WILL BE
ROTATING TO THE EAST AND NORTHEAST TODAY/TONIGHT. SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS WERE DEVELOPING AHEAD OF IT...WITH
COVERAGE EXPECTED TO INCREASE THIS AFTERNOON. PEA-SIZED OR A BIT
SMALLER HAIL WAS REPORTED FROM STORM OVER ORCHARD MESA (NEAR GRAND
JCT) AND ANOTHER NEAR MONTROSE EARLIER...AND THIS POSSIBILITY
SHOULD PERSIST THROUGH THE AFTERNOON. FREEZING LEVEL ON THIS
MORNING/S GJT SOUNDING WAS AROUND 11500 FT MSL. CURRENT FORECAST
LOOKS ON TRACK.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 314 AM MDT SAT MAY 18 2013

LIGHT SHOWERS QUICKLY DEVELOPING ACROSS EASTERN UTAH AND EXTREME
WESTERN COLORADO THIS MORNING IN DIFLUENT PATTERN OUT AHEAD OF
THE NEXT SHRTWV AND ASSOCIATED SFC FRONT. THIS SYSTEM WILL
PROGRESS SLOWLY EAST THROUGH THE FORECAST AREA TODAY...WITH
SHOWERS AND THUNDERSTORMS BECOMING FAIRLY WIDESPREAD BY THIS
AFTERNOON. HAVE BOOSTED POPS CONSIDERABLE ACROSS THE BOARD AND
ADJUSTED TIMING TO FIT WITH THE LATEST SHORT TERM MODELS. LOW
LEVELS WILL TAKE A BIT TO SATURATE...SO EARLY SHOWERS WILL BE A
BIT GUSTY...BUT EFFICIENT RAIN PRODUCERS WITH PRECIPITABLE WATER
VALUES IN EXCESS OF 0.50 INCH. SNOW LEVELS LOOK TO BE AROUND 10K
TODAY...ALTHOUGH CONVECTION WILL DRIVE IT DOWN TO NEAR THE 9K
LEVEL AT TIMES. NO SIGNIFICANT DAYTIME ACCUMULATIONS ANTICIPATED.
TEMPERATURES WILL BE MUCH COOLER TODAY WITH CLOUD COVER AND
FRONTAL PASSAGE EXPECTED THIS AFTERNOON.

UPPER LEVEL TROUGH PASSAGE OCCURS TONIGHT WITH THE 85KT JET CURVED
SOUTH OF THE FOUR CORNERS. WEAK COLD ADVECTION...CYCLONIC
FLOW...AND NW SLOPE OROGRAPHICS ALL INDICATE SHOWERS WILL CONTINUE
MAINLY OVER THE NORTH AND INTO THE CENTRAL MOUNTAINS. SNOW LEVELS
DROP TO AROUND 7500FT NORTH TO 10000FT SOUTH WITH 1-3 INCH
ACCUMULATIONS POSSIBLE OVER THE NORTHERN MTNS.

NW FLOW CONTINUES THROUGH MONDAY NIGHT BRINGING A COOL AND UNSETTLED
PERIOD. SUNDAY A SECOND OPEN WAVE DROPS THROUGH THE GREAT BASIN.
THIS BUILDS A BRIEF RIDGE OVER THE REGION THAT WILL DIMINISH POPS
BUT AFTERNOON CONVECTIVE SHOWERS REMAIN POSSIBLE. SNOW LEVELS RISE
TO ABOVE 10KFT MELTING MUCH OF THE SNOW THAT FELL IN THE HIGH
COUNTRY THE NIGHT BEFORE.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 314 AM MDT SAT MAY 18 2013

SUNDAY NIGHT-MONDAY...THE SECOND WAVE WORKS ACROSS THE REGION EARLY
MONDAY WITH THE BEST QG FORCING PROGGED TO PASS THROUGH THE SOUTHERN
PORTION OF THE FORECAST AREA. DIVERGENCE ALOFT IS CENTERED OVER THE
NORTH THROUGH THE AFTERNOON THAT MAY PROVIDE MORE CONVECTIVE
POTENTIAL. SNOW LEVELS LOWER TO AROUND 8KFT OVERNIGHT BUT RISE CLOSE
TO 10KFT THROUGH THE DAY. NIGHTTIME SNOW ACCUMULATIONS WILL MOSTLY
MELT AWAY THROUGH THE DAYTIME.

MONDAY NIGHT...THE TROUGH EXITS EAST AS A RIDGE BUILDS INTO THE
GREAT BASIN. SHOWERS WILL END QUICKLY WEST TO EAST THROUGH THE
EVENING.

RIDGING BUILDS IN TUESDAY AND WEDNESDAY WITH ONLY A FEW HIGH
MOUNTAIN SHOWERS EXPECTED DURING THE AFTERNOON AND EVENING HOURS
AS WE WORK OUT ANY LINGERING MOISTURE. DRY SOUTHWEST FLOW THEN
SETS IN THURSDAY AND WILL CONTINUE INTO THE WEEKEND WITH
TEMPERATURES RETURNING TO ABOVE SEASONAL NORMS AS WE CLOSE OUT
THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1102 AM MDT SAT MAY 18 2013

SCATTERED TO NUMEROUS -SHRA/-TSRA ARE EXPECTED THIS AFTERNOON
THROUGH 03Z THIS EVENING BEFORE DECREASING AND BECOMING MORE FOCUSED
ON THE NORTHERN AND CENTRAL MOUNTAINS IN WESTERN COLORADO AFTER 03Z.
SMALL HAIL AND GUSTY WINDS ARE POSSIBLE FROM SOME THUNDERSTORMS THIS
AFTERNOON. SNOW LEVEL AS LOW AS 8500 TO 9000 FT MSL IN CONVECTIVE
SHOWERS. EXPECT MOUNTAIN OBSCURATIONS AS CIGS LOWER IN THE VICINITY
OF SHOWERS WITH AREAS OF MVFR AND EVEN IFR CONDS EXPECTED. AT THE
TAF SITES...VFR CONDITIONS SHOULD BE THE RULE THOUGH A BRIEF PERIOD
OF MVFR CIGS IS POSSIBLE IN A THUNDERSTORM.

&&

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

$$

UPDATE...JAD
SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...JAD

000
FXUS65 KGJT 180915
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
315 AM MDT SAT MAY 18 2013

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 314 AM MDT SAT MAY 18 2013

LIGHT SHOWERS QUICKLY DEVELOPING ACROSS EASTERN UTAH AND EXTREME
WESTERN COLORADO THIS MORNING IN DIFLUENT PATTERN OUT AHEAD OF
THE NEXT SHRTWV AND ASSOCIATED SFC FRONT. THIS SYSTEM WILL
PROGRESS SLOWLY EAST THROUGH THE FORECAST AREA TODAY...WITH
SHOWERS AND THUNDERSTORMS BECOMING FAIRLY WIDESPREAD BY THIS
AFTERNOON. HAVE BOOSTED POPS CONSIDERABLE ACROSS THE BOARD AND
ADJUSTED TIMING TO FIT WITH THE LATEST SHORT TERM MODELS. LOW
LEVELS WILL TAKE A BIT TO SATURATE...SO EARLY SHOWERS WILL BE A
BIT GUSTY...BUT EFFICIENT RAIN PRODUCERS WITH PRECIPITABLE WATER
VALUES IN EXCESS OF 0.50 INCH. SNOW LEVELS LOOK TO BE AROUND 10K
TODAY...ALTHOUGH CONVECTION WILL DRIVE IT DOWN TO NEAR THE 9K
LEVEL AT TIMES. NO SIGNIFICANT DAYTIME ACCUMULATIONS ANTICIPATED.
TEMPERATURES WILL BE MUCH COOLER TODAY WITH CLOUD COVER AND
FRONTAL PASSAGE EXPECTED THIS AFTERNOON.

UPPER LEVEL TROUGH PASSAGE OCCURS TONIGHT WITH THE 85KT JET CURVED
SOUTH OF THE FOUR CORNERS. WEAK COLD ADVECTION...CYCLONIC
FLOW...AND NW SLOPE OROGRAPHICS ALL INDICATE SHOWERS WILL CONTINUE
MAINLY OVER THE NORTH AND INTO THE CENTRAL MOUNTAINS. SNOW LEVELS
DROP TO AROUND 7500FT NORTH TO 10000FT SOUTH WITH 1-3 INCH
ACCUMULATIONS POSSIBLE OVER THE NORTHERN MTNS.

NW FLOW CONTINUES THROUGH MONDAY NIGHT BRINGING A COOL AND UNSETTLED
PERIOD. SUNDAY A SECOND OPEN WAVE DROPS THROUGH THE GREAT BASIN.
THIS BUILDS A BRIEF RIDGE OVER THE REGION THAT WILL DIMINISH POPS
BUT AFTERNOON CONVECTIVE SHOWERS REMAIN POSSIBLE. SNOW LEVELS RISE
TO ABOVE 10KFT MELTING MUCH OF THE SNOW THAT FELL IN THE HIGH
COUNTRY THE NIGHT BEFORE.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 314 AM MDT SAT MAY 18 2013

SUNDAY NIGHT-MONDAY...THE SECOND WAVE WORKS ACROSS THE REGION EARLY
MONDAY WITH THE BEST QG FORCING PROGGED TO PASS THROUGH THE SOUTHERN
PORTION OF THE FORECAST AREA. DIVERGENCE ALOFT IS CENTERED OVER THE
NORTH THROUGH THE AFTERNOON THAT MAY PROVIDE MORE CONVECTIVE
POTENTIAL. SNOW LEVELS LOWER TO AROUND 8KFT OVERNIGHT BUT RISE CLOSE
TO 10KFT THROUGH THE DAY. NIGHTTIME SNOW ACCUMULATIONS WILL MOSTLY
MELT AWAY THROUGH THE DAYTIME.

MONDAY NIGHT...THE TROUGH EXITS EAST AS A RIDGE BUILDS INTO THE
GREAT BASIN. SHOWERS WILL END QUICKLY WEST TO EAST THROUGH THE
EVENING.

RIDGING BUILDS IN TUESDAY AND WEDNESDAY WITH ONLY A FEW HIGH
MOUNTAIN SHOWERS EXPECTED DURING THE AFTERNOON AND EVENING HOURS
AS WE WORK OUT ANY LINGERING MOISTURE. DRY SOUTHWEST FLOW THEN
SETS IN THURSDAY AND WILL CONTINUE INTO THE WEEKEND WITH
TEMPERATURES RETURNING TO ABOVE SEASONAL NORMS AS WE CLOSE OUT
THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 314 AM MDT SAT MAY 18 2013

MID LEVEL CLOUDS AND A FEW LIGHT SHOWERS WILL MOVE ACROSS EASTERN
UTAH AND WESTERN COLORADO THIS MORNING AHEAD OF A COLD FRONT
ADVANCING ACROSS THE GREAT BASIN. THIS FRONT WILL PUSH THROUGH
WESTERN COLORADO THIS AFTERNOON AND EVENING WITH SHOWERS AND
THUNDERSTORMS BECOMING WIDESPREAD AFTER 18Z. EXPECT MOUNTAIN
OBSCURATIONS AS CIGS LOWER IN THE VICINITY OF SHOWERS WITH AREAS
OF MVFR AND EVEN IFR CONDS EXPECTED. SHOWERS ACTIVITY WILL BECOME
MORE FOCUSED ON THE NORTHERN AND CENTRAL MOUNTAINS IN WESTERN
COLORADO AFTER 03Z.

&&

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

$$

SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...JDC

000
FXUS65 KGJT 180437
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1037 PM MDT FRI MAY 17 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 356 PM MDT FRI MAY 17 2013

WATER VAPOR IMAGERY SHOWING A GOOD FETCH OF MOISTURE INTO THE
EASTERN GREAT BASIN WITH PWATS RUNNING OVER 150 PERCENT. THIS
MOISTURE IS SEEN WELL NEAR THE 315K THETA SURFACES AND WILL BE
PUSHED INTO OUR CWA LATE THIS EVENING INTO THE OVERNIGHT HOURS. VERY
DRY ATMOSPHERE IS PLACE AHEAD OF THIS MOISTURE AS 12Z KGJT RAOB
SHOWED .20 PWAT WHICH IS HALF OF NORMAL. THIS HAS PROBABLY MOISTENED
SLIGHTLY AS EVIDENCED BY THE HIGH CLOUDS MOVING OVERHEAD BUT THERE
WILL NEED TO BE SOME PROLONGED LIFT TO WORK THIS MOISTURE DOWNWARD.
LARGE SCALE ASCENT WILL BEGIN THIS TASK DURING THE OVERNIGHT HOURS
BUT IT APPEARS THE ENERGY WILL BE SPLITTING AS IT APPROACHES WESTERN
COLORADO AND THEN REFORMING ON THE EASTERN PLAINS SATURDAY
AFTERNOON. THE ATMOSPHERE WILL NEED THE CONVECTIVE BOOST FROM
HEATING TOMORROW TO BRING THE MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY. 18Z HAND ANALYSIS SHOWS A SURFACE BOUNDARY
DRAPED ACROSS CENTRAL UTAH TO A LOW ACROSS WESTERN WYOMING. THIS
FRONT LOOKS TO BE FORCED EASTWARD THROUGH OUR CWA LATE THIS EVENING
AND TO THE DIVIDE OR BEYOND BY SUNRISE ON SATURDAY. THE DYNAMICS AND
MOISTURE DO NOT SEEM TO LINK UP VERY GOOD WITH THE LOW LEVEL LIFT
AND EXPECT MAINLY A WIND SHIFT WITH THE FRONT. THE COOLER AIR MOVING
IN BEHIND THE FRONT HOWEVER WILL BE FELT WITH HIGHS DROPPING SOME 10
TO 15 DEGREES OVER THOSE FOUND TODAY. THIS SHOULD HELP ALLEVIATE THE
THREAT OF CRITICAL FIRE WEATHER OVER MOST OF THE REGION ON SATURDAY
WITH THE ADDED MOISTURE ALSO BOOSTING UP AFTERNOON RH VALUES. AS
STORMS DO FIRE THROUGH THE DAY SOME OF THE STRONGER STORMS MAY
PRODUCE SMALL HAIL AND SOME GUSTY WINDS BUT OVERALL SHEAR PROFILES
LOOK TO BE WEAKENING THROUGH THE DAY SO THE THREAT OF SEVERE LOOKS
LIMITED. EXPECT A DECENT DOWNTURN IN THE PRECIPITATION SATURDAY
EVENING BUT WEAK ASCENT AND MODERATE LAPSE RATES AS COOLER AIR
FILTERS IN ALOFT WILL KEEP SOME SHOWERS ACROSS THE CENTRAL AND
NORTHERN MOUNTAINS...POSSIBLY DRIFTING ACROSS THE NORTHERN VALLEYS
THROUGH SUNRISE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 356 PM MDT FRI MAY 17 2013

SUNDAY NIGHT A SECOND LOW DROPS DOWN INTO THE HIGH DESERT
REGION...ALLOWING BELOW NORMAL TEMPERATURES TO PERSIST THROUGH THE
START OF THE WORK WEEK. MARGINAL MOISTURE AND INSTABILITY KEEP
CONVECTIVELY DRIVEN SCATTERED SHOWERS AND STORMS POSSIBLE THROUGH
THE DAY MONDAY. SNOW LEVELS ARE PROGGED TO LOWER TO 7000FT FEET
SUNDAY NIGHT IN THE VERY EASTERN SECTION OF THE CWA NEAR VAIL...BUT
IS NOT ANTICIPATED TO GREATLY IMPACT THE PASSES AS PRECIPITATION
AMOUNTS WILL BE SMALL.

MONDAY NIGHT A RIDGE BEGINS TO SHIFT EASTWARD INTO THE
AREA...ALLOWING DRY AIR TO BEGIN FILTERING INTO THE REGION. AS
THIS RIDGE MOVES EAST TUESDAY...TEMPERATURES WILL TRANSITION BACK TO
NORMAL OVER EASTERN UT/WESTERN CO.

WEDNESDAY...SOUTHWEST FLOW ON THE BACKSIDE OF THE RIDGE WILL ALLOW
TEMPERATURES 5 TO 10 DEGREES ABOVE NORMAL AND DRIER CONDITIONS TO
RETURN TO THE REGION. A LARGER SYSTEM DROPPING INTO THE PACIFIC
NORTHWEST REGION WILL HELP MAINTAIN THIS SOUTHWEST FLOW THROUGH THE
END OF THE WEEK. THIS SHOULD ALLOW TEMPERATURES BACK TO AND ABOVE
NORMAL BY LATE WEEK. THERE IS LITTLE THREAT OF PRECIPITATION THROUGH
LATE WEEK WITH THE EXCEPTION OF CONVECTIVELY DRIVEN SHOWERS AND
THUNDERSTORMS IN THE CENTRAL MOUNTAINS BEGINNING MID-WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 356 PM MDT FRI MAY 17 2013

SOME MID TO HIGH LEVEL CLOUDS ARE CROSSING THE FORECAST THIS
EVENING WITH VARYING COVERAGE FROM SCT TO OVC. THIS WILL CONTINUE
BUT FLIGHT CONDITIONS WILL REMAIN VFR. IN FACT...VFR WILL CONTINUE
THROUGH TOMORROW AFTERNOON UNTIL AN UPPER LEVEL TROUGH AND ASSOD
COLD FRONT MOVES THROUGH. WIDESPREAD CONVECTION IS EXPECTED WITH
HIGHER TERRAIN BEING FAVORED THOUGH SOME STORMS WILL MOST LIKELY
DRIFT INTO THE VALLEYS. FEEL CONFIDENT IN VCTS FOR ALL TAF SITES
THOUGH WILL HOLD OFF ON ANY TEMPO GROUPS AS FROPA IS SO FAR OUT.
EXPECT MVFR NEAR AND UNDER THE STRONGER STORMS WITH GUSTY SURFACE
WINDS AND BRIEF HEAVY RAIN DROPPING CONDITIONS TO MVFR...POSSIBLY
EVEN IFR AT TIMES...BEFORE QUICKLY RETURNING TO VFR.

&&

.FIRE WEATHER...(TODAY THROUGH WEDNESDAY)
ISSUED AT 1036 PM MDT FRI MAY 17 2013

SOUTHWEST WINDS WITH GUSTS IN THE 25 TO 35 MPH RANGE ALONG WITH
HUMIDITY VALUES IN THE SINGLE DIGITS AND TEENS WILL CONTINUE
TO BRING CRITICAL FIRE WEATHER CONDITIONS TO MANY LOWER ELEVATIONS
IN SOUTHWEST COLORADO THROUGH SUNSET WHERE FUELS ARE DRY. THE
SYSTEM RESPONSIBLE FOR THE WARM AND DRY...AND WINDY CONDITIONS
WILL BE SHIFTING OVER EASTERN UTAH AND WESTERN COLORADO OVER THE
NEXT 24 HOURS. THIS WILL BRING COOLER TEMPERATURES AND A CHANCE OF
PRECIPITATION TO THE REGION AND LOWER CRITICAL FIRE WEATHER
CONCERNS. MANY ELEVATIONS OVER 8000 FEET MAY RECEIVE WETTING
RAINS...BUT LOWER ELEVATIONS THIS WILL BE MORE SPOTTY.

&&

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

&&

$$

SHORT TERM...15
LONG TERM...JAM
AVIATION...TGR
FIRE WEATHER...15

000
FXUS65 KGJT 172156
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
356 PM MDT FRI MAY 17 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 356 PM MDT FRI MAY 17 2013

WATER VAPOR IMAGERY SHOWING A GOOD FETCH OF MOISTURE INTO THE
EASTERN GREAT BASIN WITH PWATS RUNNING OVER 150 PERCENT. THIS
MOISTURE IS SEEN WELL NEAR THE 315K THETA SURFACES AND WILL BE
PUSHED INTO OUR CWA LATE THIS EVENING INTO THE OVERNIGHT HOURS. VERY
DRY ATMOSPHERE IS PLACE AHEAD OF THIS MOISTURE AS 12Z KGJT RAOB
SHOWED .20 PWAT WHICH IS HALF OF NORMAL. THIS HAS PROBABLY MOISTENED
SLIGHTLY AS EVIDENCED BY THE HIGH CLOUDS MOVING OVERHEAD BUT THERE
WILL NEED TO BE SOME PROLONGED LIFT TO WORK THIS MOISTURE DOWNWARD.
LARGE SCALE ASCENT WILL BEGIN THIS TASK DURING THE OVERNIGHT HOURS
BUT IT APPEARS THE ENERGY WILL BE SPLITTING AS IT APPROACHES WESTERN
COLORADO AND THEN REFORMING ON THE EASTERN PLAINS SATURDAY
AFTERNOON. THE ATMOSPHERE WILL NEED THE CONVECTIVE BOOST FROM
HEATING TOMORROW TO BRING THE MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY. 18Z HAND ANALYSIS SHOWS A SURFACE BOUNDARY
DRAPED ACROSS CENTRAL UTAH TO A LOW ACROSS WESTERN WYOMING. THIS
FRONT LOOKS TO BE FORCED EASTWARD THROUGH OUR CWA LATE THIS EVENING
AND TO THE DIVIDE OR BEYOND BY SUNRISE ON SATURDAY. THE DYNAMICS AND
MOISTURE DO NOT SEEM TO LINK UP VERY GOOD WITH THE LOW LEVEL LIFT
AND EXPECT MAINLY A WIND SHIFT WITH THE FRONT. THE COOLER AIR MOVING
IN BEHIND THE FRONT HOWEVER WILL BE FELT WITH HIGHS DROPPING SOME 10
TO 15 DEGREES OVER THOSE FOUND TODAY. THIS SHOULD HELP ALLEVIATE THE
THREAT OF CRITICAL FIRE WEATHER OVER MOST OF THE REGION ON SATURDAY
WITH THE ADDED MOISTURE ALSO BOOSTING UP AFTERNOON RH VALUES. AS
STORMS DO FIRE THROUGH THE DAY SOME OF THE STRONGER STORMS MAY
PRODUCE SMALL HAIL AND SOME GUSTY WINDS BUT OVERALL SHEAR PROFILES
LOOK TO BE WEAKENING THROUGH THE DAY SO THE THREAT OF SEVERE LOOKS
LIMITED. EXPECT A DECENT DOWNTURN IN THE PRECIPITATION SATURDAY
EVENING BUT WEAK ASCENT AND MODERATE LAPSE RATES AS COOLER AIR
FILTERS IN ALOFT WILL KEEP SOME SHOWERS ACROSS THE CENTRAL AND
NORTHERN MOUNTAINS...POSSIBLY DRIFTING ACROSS THE NORTHERN VALLEYS
THROUGH SUNRISE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 356 PM MDT FRI MAY 17 2013

SUNDAY NIGHT A SECOND LOW DROPS DOWN INTO THE HIGH DESERT
REGION...ALLOWING BELOW NORMAL TEMPERATURES TO PERSIST THROUGH THE
START OF THE WORK WEEK. MARGINAL MOISTURE AND INSTABILITY KEEP
CONVECTIVELY DRIVEN SCATTERED SHOWERS AND STORMS POSSIBLE THROUGH
THE DAY MONDAY. SNOW LEVELS ARE PROGGED TO LOWER TO 7000FT FEET
SUNDAY NIGHT IN THE VERY EASTERN SECTION OF THE CWA NEAR VAIL...BUT
IS NOT ANTICIPATED TO GREATLY IMPACT THE PASSES AS PRECIPITATION
AMOUNTS WILL BE SMALL.

MONDAY NIGHT A RIDGE BEGINS TO SHIFT EASTWARD INTO THE
AREA...ALLOWING DRY AIR TO BEGIN FILTERING INTO THE REGION. AS
THIS RIDGE MOVES EAST TUESDAY...TEMPERATURES WILL TRANSITION BACK TO
NORMAL OVER EASTERN UT/WESTERN CO.

WEDNESDAY...SOUTHWEST FLOW ON THE BACKSIDE OF THE RIDGE WILL ALLOW
TEMPERATURES 5 TO 10 DEGREES ABOVE NORMAL AND DRIER CONDITIONS TO
RETURN TO THE REGION. A LARGER SYSTEM DROPPING INTO THE PACIFIC
NORTHWEST REGION WILL HELP MAINTAIN THIS SOUTHWEST FLOW THROUGH THE
END OF THE WEEK. THIS SHOULD ALLOW TEMPERATURES BACK TO AND ABOVE
NORMAL BY LATE WEEK. THERE IS LITTLE THREAT OF PRECIPITATION THROUGH
LATE WEEK WITH THE EXCEPTION OF CONVECTIVELY DRIVEN SHOWERS AND
THUNDERSTORMS IN THE CENTRAL MOUNTAINS BEGINNING MID-WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 356 PM MDT FRI MAY 17 2013

DRY SOUTHWEST FLOW WILL KEEP VFR CONDITIONS IN PLACE THROUGH
TOMORROW MORNING. SPORADIC WIND GUSTS OF 25 TO 35 KTS WILL CONTINUE
THROUGH THIS EVENING THROUGHOUT EASTERN UT/WESTERN CO. SHOWERS
ASSOCIATED WITH COLD FRONT WILL MOVE INTO EASTERN UTAH OVERNIGHT
FRIDAY AND WESTERN COLORADO SATURDAY MORNING. POSSIBILITY OF MVFR
OVER THE MOUNTAINS TOMORROW AFTERNOON FOR A FEW HOURS AS MOISTURE
ASSOCIATED WITH COLD FRONT PASSES THROUGH.

&&

.FIRE WEATHER...(TODAY THROUGH WEDNESDAY)
ISSUED AT 356 PM MDT FRI MAY 17 2013

SOUTHWEST WINDS WITH GUSTS IN THE 25 TO 35 MPH RANGE ALONG WITH
HUMIDITY VALUES IN THE SINGLE DIGITS AND TEENS WILL CONTINUE
TO BRING CRITICAL FIRE WEATHER CONDITIONS TO MANY LOWER ELEVATIONS
IN SOUTHWEST COLORADO THROUGH SUNSET WHERE FUELS ARE DRY. THE
SYSTEM RESPONSIBLE FOR THE WARM AND DRY...AND WINDY CONDITIONS
WILL BE SHIFTING OVER EASTERN UTAH AND WESTERN COLORADO OVER THE
NEXT 24 HOURS. THIS WILL BRING COOLER TEMPERATURES AND A CHANCE OF
PRECIPITATION TO THE REGION AND LOWER CRITICAL FIRE WEATHER
CONCERNS. MANY ELEVATIONS OVER 8000 FEET MAY RECEIVE WETTING
RAINS...BUT LOWER ELEVATIONS THIS WILL BE MORE SPOTTY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ203-207-290-
     292-293.

UT...NONE.
&&

$$

SHORT TERM...15
LONG TERM...JAM
AVIATION...JAM
FIRE WEATHER...15

000
FXUS65 KGJT 171646
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1046 AM MDT FRI MAY 17 2013

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 320 AM MDT FRI MAY 17 2013

DRY SOUTHWEST FLOW WILL BE IN PLACE TODAY WITH SFC WINDS
INCREASING THIS AFTERNOON. EXPECT BREEZY CONDITIONS WITH DEEP
MIXING TO OVER 500MB WITH GUST POTENTIAL TO NEAR 40 MPH SHOULD
DEEPEST MIXING BECOME REALIZED. HAVE DROPPED MENTION OF SINGLE
DIGIT POPS FROM THE GRIDS...WITH ONLY A LATE DAY INCREASE ACROSS
THE EASTERN UINTA MOUNTAINS AS PACIFIC SYSTEM MOVES INTO THE
WESTERN GREAT BASIN AND NUDGES A LITTLE BETTER MOISTURE INTO THIS
AREA. TEMPERATURES WILL REMAIN WELL ABOVE SEASONAL NORMS FOR MAX
TEMPS TODAY.

UPPER TROUGH WORKS FROM NEVADA TONIGHT INTO EASTERN UTAH BY EARLY
SATURDAY. MID TO HIGH LEVEL MOISTURE INCREASES OVERNIGHT INTO
SATURDAY TO JUST OVER HALF AN INCH PRECIPITABLE WATER. DISORGANIZED
VORTICITY LOBES PASS OVER THE NORTHERN AND CENTRAL FORECAST AREA
SATURDAY THAT WILL COMBINE WITH AFTERNOON HEATING TO PRODUCE
SCATTERED STORMS AND SHOWERS. MODELS ARE PRODUCING SHOWERS OF AROUND
0.1 INCHES OVER HIGHER TERRAIN. WITH WET BULB ZERO NEAR 10KFT SMALL
HAIL WILL FALL FROM THE STRONGER CORES.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 320 AM MDT FRI MAY 17 2013

SATURDAY NIGHT THE TROUGH WORKS THROUGH THE REGION SHIFTING THE FLOW
TO NW. SCATTERED SHOWERS AND ISOLATED STORMS MAY CONTINUE THROUGH
THE NIGHT.  NEAR NORMAL TEMPERATURES EXPECTED OVERNIGHT.  SNOW
LEVELS LOWER TO 9KFT WITH A FEW INCHES OF SNOW POSSIBLE.

SUNDAY IN NW FLOW A SECOND PIECE OF ENERGY DROPS THROUGH THE GREAT
BASIN THEN INTO THE FORECAST AREA SUNDAY NIGHT. AN 80KT JET WRAPS
ACROSS THE SOUTHERN CWA SUNDAY INTO SUNDAY NIGHT. TEMPERATURES FALL
BELOW NORMAL FOR A CHANGE. MARGINAL MOISTURE AND INSTABILITY KEEP
SCATTERED SHOWERS AND STORMS WITH SMALL HAIL THROUGH THE DAY AND
NIGHT. SNOW LEVELS ARE PROGGED TO LOWER AS LOW AT 8KFT FEET.

COOLER START TO THE NEW WORK WEEK BEHIND THE EXITING TROUGH WITH
SCATTERED SHOWERS LINGERING THROUGH MONDAY NIGHT. CONDITIONS DRY
OUT AND START TO WARM BACK UP BY TUESDAY AFTERNOON WITH SHRTWV
RIDGING BUILDING IN FROM THE WEST. RIDGE TRANSLATES QUICKLY EAST
BY WEDNESDAY WITH DRY SOUTHWEST FLOW RESUMING AS ANOTHER STRONG
LOW PRESSURE SYSTEM DIGS INTO THE PACNW. ATTM...MEDIUM RANGE
MODELS IN AGREEMENT WITH THIS SYSTEM STALLING TO OUR WEST...WITH
DRY CONDITIONS LIKELY PERSISTING THROUGH THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1032 AM MDT FRI MAY 17 2013

DRY SOUTHWEST FLOW WILL KEEP VFR CONDITIONS IN PLACE THROUGH TONIGHT.
LOCAL SURFACE GUSTS OF 25 TO 35 KTS WILL CONTINUE THROUGH THIS
EVENING AT KGJT...KMTJ...KCNY...AND KRIL. SHOWERS ASSOCIATED WITH
COLD FRONT WILL MOVE INTO EASTERN UTAH LATE FRIDAY AND WESTERN
COLORADO SATURDAY MORNING.

&&

.FIRE WEATHER...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM MDT FRI MAY 17 2013

STRONG AFTERNOON SURFACE HEATING ON FRIDAY WILL PRODUCE DEEP MIXING
AND ALLOW INCREASING GRADIENT SW WINDS TO MIX DOWN TO THE SURFACE.
AFTERNOON RELATIVE HUMIDITY WILL FALL INTO THE LOWER TEENS AND DRY
FUELS WILL COMBINE WITH THE STRONGER WINDS TO PRODUCE CRITICAL FIRE
WEATHER CONDITIONS. THE WESTERN TROF WILL APPROACH ON SATURDAY AND
PASS SATURDAY NIGHT PRODUCING ACTIVE WEATHER THROUGH EARLY NEXT WEEK
BEFORE UPPER RIDGING MOVE BACK INTO THE ROCKIES. COOLER WEATHER THIS
WEEKEND WILL THEN GRADUALLY WARM THROUGH NEXT WEEK WITH MAINLY DRY
CONDITIONS EXPECTED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ203-207-290-
     292-293.

UT...NONE.
&&

$$

SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...JAM
FIRE WEATHER...JOE

000
FXUS65 KGJT 170921
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
321 AM MDT FRI MAY 17 2013

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 320 AM MDT FRI MAY 17 2013

DRY SOUTHWEST FLOW WILL BE IN PLACE TODAY WITH SFC WINDS
INCREASING THIS AFTERNOON. EXPECT BREEZY CONDITIONS WITH DEEP
MIXING TO OVER 500MB WITH GUST POTENTIAL TO NEAR 40 MPH SHOULD
DEEPEST MIXING BECOME REALIZED. HAVE DROPPED MENTION OF SINGLE
DIGIT POPS FROM THE GRIDS...WITH ONLY A LATE DAY INCREASE ACROSS
THE EASTERN UINTA MOUNTAINS AS PACIFIC SYSTEM MOVES INTO THE
WESTERN GREAT BASIN AND NUDGES A LITTLE BETTER MOISTURE INTO THIS
AREA. TEMPERATURES WILL REMAIN WELL ABOVE SEASONAL NORMS FOR MAX
TEMPS TODAY.

UPPER TROUGH WORKS FROM NEVADA TONIGHT INTO EASTERN UTAH BY EARLY
SATURDAY. MID TO HIGH LEVEL MOISTURE INCREASES OVERNIGHT INTO
SATURDAY TO JUST OVER HALF AN INCH PRECIPITABLE WATER. DISORGANIZED
VORTICITY LOBES PASS OVER THE NORTHERN AND CENTRAL FORECAST AREA
SATURDAY THAT WILL COMBINE WITH AFTERNOON HEATING TO PRODUCE
SCATTERED STORMS AND SHOWERS. MODELS ARE PRODUCING SHOWERS OF AROUND
0.1 INCHES OVER HIGHER TERRAIN. WITH WET BULB ZERO NEAR 10KFT SMALL
HAIL WILL FALL FROM THE STRONGER CORES.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 320 AM MDT FRI MAY 17 2013

SATURDAY NIGHT THE TROUGH WORKS THROUGH THE REGION SHIFTING THE FLOW
TO NW. SCATTERED SHOWERS AND ISOLATED STORMS MAY CONTINUE THROUGH
THE NIGHT.  NEAR NORMAL TEMPERATURES EXPECTED OVERNIGHT.  SNOW
LEVELS LOWER TO 9KFT WITH A FEW INCHES OF SNOW POSSIBLE.

SUNDAY IN NW FLOW A SECOND PIECE OF ENERGY DROPS THROUGH THE GREAT
BASIN THEN INTO THE FORECAST AREA SUNDAY NIGHT. AN 80KT JET WRAPS
ACROSS THE SOUTHERN CWA SUNDAY INTO SUNDAY NIGHT. TEMPERATURES FALL
BELOW NORMAL FOR A CHANGE. MARGINAL MOISTURE AND INSTABILITY KEEP
SCATTERED SHOWERS AND STORMS WITH SMALL HAIL THROUGH THE DAY AND
NIGHT. SNOW LEVELS ARE PROGGED TO LOWER AS LOW AT 8KFT FEET.

COOLER START TO THE NEW WORK WEEK BEHIND THE EXITING TROUGH WITH
SCATTERED SHOWERS LINGERING THROUGH MONDAY NIGHT. CONDITIONS DRY
OUT AND START TO WARM BACK UP BY TUESDAY AFTERNOON WITH SHRTWV
RIDGING BUILDING IN FROM THE WEST. RIDGE TRANSLATES QUICKLY EAST
BY WEDNESDAY WITH DRY SOUTHWEST FLOW RESUMING AS ANOTHER STRONG
LOW PRESSURE SYSTEM DIGS INTO THE PACNW. ATTM...MEDIUM RANGE
MODELS IN AGREEMENT WITH THIS SYSTEM STALLING TO OUR WEST...WITH
DRY CONDITIONS LIKELY PERSISTING THROUGH THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 320 AM MDT FRI MAY 17 2013

DRY SOUTHWEST FLOW WILL KEEP VFR CONDITIONS IN PLACE THROUGH THIS
TONIGHT. AFTER 18Z...LOCAL SURFACE GUSTS OF 25 TO 35 KTS WILL BE
POSSIBLE AT THE DESERT AIRPORTS (KGJT...KCNY...KMTJ...KRIL) WITH
THE GUSTY WINDS DIMINISHING BY 03Z THIS EVENING.

&&

.FIRE WEATHER...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM MDT FRI MAY 17 2013

STRONG AFTERNOON SURFACE HEATING ON FRIDAY WILL PRODUCE DEEP MIXING
AND ALLOW INCREASING GRADIENT SW WINDS TO MIX DOWN TO THE SURFACE.
AFTERNOON RELATIVE HUMIDITY WILL FALL INTO THE LOWER TEENS AND DRY
FUELS WILL COMBINE WITH THE STRONGER WINDS TO PRODUCE CRITICAL FIRE
WEATHER CONDITIONS. THE WESTERN TROF WILL APPROACH ON SATURDAY AND
PASS SATURDAY NIGHT PRODUCING ACTIVE WEATHER THROUGH EARLY NEXT WEEK
BEFORE UPPER RIDGING MOVE BACK INTO THE ROCKIES. COOLER WEATHER THIS
WEEKEND WILL THEN GRADUALLY WARM THROUGH NEXT WEEK WITH MAINLY DRY
CONDITIONS EXPECTED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM NOON TODAY TO 8 PM MDT THIS EVENING FOR
     COZ203-207-290-292-293.

UT...NONE.
&&

$$

SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...JDC
FIRE WEATHER...JOE

000
FXUS65 KGJT 170359
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
959 PM MDT THU MAY 16 2013

.UPDATE...
ISSUED AT 959 PM MDT THU MAY 16 2013

MID CLOUD LAYER INHIBITED DEEP LAYERED MIXING THIS AFTERNOON AND
ELECTED TO CANCEL THE RED FLAG WARNING EARLY. CONDITIONS
APPROACHED CRITICAL...THE WIDESPREAD GUSTY WINDS DID NOT
MATERIALIZED.

DIURNAL DRIVEN CONVECTION HAS ESSENTIALLY DISSIPATED ACROSS
NORTHWEST COLORADO...ALTHOUGH SOME SPRINKLES MAY OCCUR...THESE
WILL BE ENDING WITHIN THE HOUR OR TWO.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 355 PM MDT THU MAY 16 2013

SOME ISOLATED SHOWERS AND STORMS HAVE FORMED THIS AFTERNOON MAINLY
OVER THE BOOKCLIFFS AND ROAN/TAVAPUT PLATEAUS. THIS FOLLOWS SINCE
PWATS ARE HIGHER OVER THIS AREA AS IS THE AVAILABLE ENERGY FOR ANY
STORMS THAT FORM. AN ISOLD SHOWER/STORM IS ALSO POSSIBLE OVER THE SAN
JUANS THROUGH THIS EVENING BUT AS OF NOW...RADAR MOSAIC NOT
PICKING UP ON ANY STORMS. ONCE DAYTIME HEATING ENDS...CONVECTION
WILL QUICKLY DIE DOWN GIVING WAY TO CLEARING SKIES OVERNIGHT.

THE POLAR JET WILL CONTINUE TO DIG OFF THE PACIFIC COAST CAUSING
HGT FALLS ACROSS THE INTERMOUNTAIN WEST. AS PIECES OF ENERGY ROUND
THE BASE OF THE TROUGH...UPPER LEVEL SUPPORT WILL FAVOR PRECIP
OVER NRN NV/UT WHILE KEEPING OUR FORECAST AREA DRY. AS THE TROUGH
APPROACHES...THE PRESSURE GRADIENT WILL TIGHTEN CAUSING SOME
GUSTY SURFACE WINDS OF 25 TO 30 MPH AT TIMES. THESE WINDS...ALONG
WITH DRY CONDITIONS...WILL CREATE RED FLAG CONDITIONS AS DESCRIBED
IN THE FIRE WEATHER SECTION BELOW. ASIDE FROM THE GUSTY
WINDS...PLENTY OF SUN EXPECTED WITH ABOVE AVERAGE TEMPERATURES CONTINUING.

GFS/NAM/EC CONTINUE TO DELAY THE ONSET OF PRECIP WITH THE ASSOD
TROUGH/FRONT SATURDAY WITH SOME LGT PRECIP EXPECTED IN THE MORNING
BEFORE MORE WIDESPREAD PRECIP KICKS IN FROM NOON ONWARDS. COLD
FRONT LOOKS TO BE JUST WEST OF THE UT/CO BORDER NOON
SATURDAY...CROSSING THE GRAND VALLEY MIDAFTERNOON AND ACROSS THE
REST OF WESTERN COLORADO BY THE EVENING HOURS. SOME INTERESTING
ASPECTS TO THIS SYSTEM...THE H5 TROUGH WILL BE NEGATIVELY TILTED
WHICH INDICATES THE POSSIBILITY FOR STRONGER...MORE INTENSE
CONVECTION. SFC CAPE NOT FOLLOWING THIS THINKING THOUGH AS VALUES
TOP OUT AROUND 500 J/KG WITH MOST VALUES BETWEEN 200 TO 300
J/KG...FAIRLY WEAK. QG FORCING ALSO REACHES A MAXIMUM TO OUR
SOUTH. ALL OF THE INGREDIENTS ARE IN PLACE FOR SOME ACTIVE
WX...JUST NOT LINED UP AS WELL AS THEY COULD BE.
REGARDLESS...PLENTY OF WEATHER TO BE HAD SATURDAY WITH
SHOWERS/STORMS INCREASING DURING THE DAY AS THE FRONT MOVES
THROUGH.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 355 PM
MDT THU MAY 16 2013

THE STRONGEST PART OF THE ASCENT WITH THIS NEGATIVELY TILTED TROF
WILL BE RE-FOCUSING ON THE PLAINS SATURDAY EVENING. THIS SHOULD
ALLOW FOR A NOTICEABLE DOWNTURN TO THE CONVECTION AFTER SUNSET WITH
ISOLATED TO WIDELY SCATTERED STORMS LINGERING THROUGH THE MORNING
HOURS MAINLY OVER THE TERRAIN. THE STRONG RIDGING AHEAD OF THIS TROF
AND HIGH PRESSURE TO THE NORTH WILL ALLOW THE NEXT UPSTREAM SYSTEM
TO DIG INTO THE REAR OF THE LEAD TROF SUNDAY...EVENTUALLY FORMING A
REX LOW OVER THE UPPER MISSOURI VALLEY BY SUNDAY NIGHT. THIS
NORTHERN PLAINS LOW WILL BE SLOW TO MOVE EASTWARD AND WILL KEEP A
THREAT OF UNSETTLED WEATHER ACROSS THE EASTERN 2/3 OF OUR CWA GOING
INTO THE EARLY WEEK PERIOD.

COOLER AIR FILTERING INTO THE TROF SUNDAY WILL ALLOW FAIRLY
WIDESPREAD CONVECTION TO FORM OVER THE NORTHERN AND CENTRAL
MOUNTAINS SUNDAY AS THE ATMOSPHERE DESTABILIZES. QG FIELDS INDICATE
THE BETTER FORCING DROPPING INTO NORTHERN UTAH LATE IN THE DAY WHICH
WILL BE SWEEPING ACROSS COLORADO THROUGH THE EVENING. SUPPORTING
THIS WAVE WILL RIGHT EXIT REGION OF THE CYCLONIC JET WHICH SHOULD
KEEP SOME SHOWER ACTIVITY GOING ACROSS THE NORTHERN MOUNTAIN THROUGH
THE EARLY MORNING HOURS EVEN AS DRIER AIR BEGINS TO FILTER IN.
TEMPERATURES WILL COOLING OFF QUITE A BIT GOING INTO SUNDAY WITH
HIGHS RUNNING SOME 10 DEGREES OR SO BELOW NORMAL. H7 TEMPERATURES
LOWER TO NEAR FREEZING OVERNIGHT ACROSS THE NORTHERN COLORADO
MOUNTAIN WHICH MAY LEAVE SOME LIGHT SNOW ACCUMULATION ACROSS THE
HIGHER PEAKS...WITH LITTLE IMPACT TO THE PASSES EXPECTED.
CONVECTIVELY DRIVEN SHOWERS WILL PERSIST INTO MONDAY IN NORTHWEST
FLOW WITH COOL ADVECTION THROUGH THE DAY. TEMPERATURES WILL REMAIN
BELOW NORMAL UNDER THIS FLOW WITH WAA NOT MOVING UNTIL THE OVERNIGHT
HOURS.

TUESDAY SHOULD BE THE TRANSITION DAY BEFORE MUCH WARMER TEMPERATURES
AND DRIER CONDITIONS MOVE INTO THE REGION. A LARGER SYSTEM DROPPING
INTO THE PACIFIC NORTHWEST REGION WILL HELP PUSH A RIDGE BACK INTO
THE ROCKIES BY MID-WEEK BEFORE THE SOUTHWEST FLOW AHEAD OF THIS
FEATURE BUILDS IN BY THE LATE WEEK PERIOD. THIS SHOULD PUSH
TEMPERATURES BACK TO AND ABOVE NORMAL BY LATE WEEK. A TIGHTENING
PRESSURE GRADIENT AND STRONG MIXING MAY ONCE AGAIN BRING FIRE
WEATHER CONCERNS TO THE FOREFRONT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 959 PM MDT THU MAY 16 2013

WIDESPREAD VFR EXPECTED FOR THE NEXT 24 HOURS.

AFTER 18Z...LOCAL SURFACE GUSTS OF 25 TO 35 KTS WILL BE POSSIBLE
AT THE DESERT AIRPORTS (LIKE KGJT...KCNY...KMTJ...KRIL).

&&

.FIRE WEATHER...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 PM MDT THU MAY 16 2013

STRONG HEATING THE NEXT FEW DAYS WILL COMBINE WITH STRONGER WINDS
ALOFT TO PRODUCE EFFICIENT MIXING PRODUCING GUSTY AFTERNOON WINDS.
RELATIVE HUMIDITY VALUES IN THE LOWER TEENS AND DRY FUELS WILL
COMBINE WITH THE STRONGER WINDS TO PRODUCE CRITICAL FIRE WEATHER
CONDITIONS DURING THE AFTERNOON AND EARLY EVENING HOURS TODAY AND
AGAIN ON FRIDAY. ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON
WILL ALSO BE CAPABLE OF PRODUCING STRONG OUTFLOW WINDS. THE DRIER
ATMOSPHERE ON FRIDAY SHOULD PROHIBIT THE THUNDERSTORM ACTIVITY. THE
WESTERN TROF WILL ARRIVE ON SATURDAY AND PRODUCE ACTIVE WEATHER
THROUGH EARLY NEXT WEEK BEFORE UPPER RIDGING MOVE BACK INTO THE
ROCKIES. COOLER WEATHER THIS WEEKEND WILL THEN GRADUALLY WARM THROUGH
NEXT WEEK WITH MAINLY DRY CONDITIONS EXPECTED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM NOON TO 8 PM MDT FRIDAY FOR COZ203-207-290-
     292-293.

UT...NONE.
&&

$$

UPDATE...PF
SHORT TERM...TGR
LONG TERM...15
AVIATION...PF

000
FXUS65 KGJT 162156
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
356 PM MDT THU MAY 16 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 355 PM MDT THU MAY 16 2013

SOME ISOLATED SHOWERS AND STORMS HAVE FORMED THIS AFTERNOON MAINLY
OVER THE BOOKCLIFFS AND ROAN/TAVAPUT PLATEAUS. THIS FOLLOWS SINCE
PWATS ARE HIGHER OVER THIS AREA AS IS THE AVAILABLE ENERGY FOR ANY
STORMS THAT FORM. AN ISOLD SHOWER/STORM IS ALSO POSSIBLE OVER THE SAN
JUANS THROUGH THIS EVENING BUT AS OF NOW...RADAR MOSAIC NOT
PICKING UP ON ANY STORMS. ONCE DAYTIME HEATING ENDS...CONVECTION
WILL QUICKLY DIE DOWN GIVING WAY TO CLEARING SKIES OVERNIGHT.

THE POLAR JET WILL CONTINUE TO DIG OFF THE PACIFIC COAST CAUSING
HGT FALLS ACROSS THE INTERMOUNTAIN WEST. AS PIECES OF ENERGY ROUND
THE BASE OF THE TROUGH...UPPER LEVEL SUPPORT WILL FAVOR PRECIP
OVER NRN NV/UT WHILE KEEPING OUR FORECAST AREA DRY. AS THE TROUGH
APPROACHES...THE PRESSURE GRADIENT WILL TIGHTEN CAUSING SOME
GUSTY SURFACE WINDS OF 25 TO 30 MPH AT TIMES. THESE WINDS...ALONG
WITH DRY CONDITIONS...WILL CREATE RED FLAG CONDITIONS AS DESCRIBED
IN THE FIRE WEATHER SECTION BELOW. ASIDE FROM THE GUSTY
WINDS...PLENTY OF SUN EXPECTED WITH ABOVE AVERAGE TEMPERATURES CONTINUING.

GFS/NAM/EC CONTINUE TO DELAY THE ONSET OF PRECIP WITH THE ASSOD
TROUGH/FRONT SATURDAY WITH SOME LGT PRECIP EXPECTED IN THE MORNING
BEFORE MORE WIDESPREAD PRECIP KICKS IN FROM NOON ONWARDS. COLD
FRONT LOOKS TO BE JUST WEST OF THE UT/CO BORDER NOON
SATURDAY...CROSSING THE GRAND VALLEY MIDAFTERNOON AND ACROSS THE
REST OF WESTERN COLORADO BY THE EVENING HOURS. SOME INTERESTING
ASPECTS TO THIS SYSTEM...THE H5 TROUGH WILL BE NEGATIVELY TILTED
WHICH INDICATES THE POSSIBILITY FOR STRONGER...MORE INTENSE
CONVECTION. SFC CAPE NOT FOLLOWING THIS THINKING THOUGH AS VALUES
TOP OUT AROUND 500 J/KG WITH MOST VALUES BETWEEN 200 TO 300
J/KG...FAIRLY WEAK. QG FORCING ALSO REACHES A MAXIMUM TO OUR
SOUTH. ALL OF THE INGREDIENTS ARE IN PLACE FOR SOME ACTIVE
WX...JUST NOT LINED UP AS WELL AS THEY COULD BE.
REGARDLESS...PLENTY OF WEATHER TO BE HAD SATURDAY WITH
SHOWERS/STORMS INCREASING DURING THE DAY AS THE FRONT MOVES
THROUGH.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 355 PM
MDT THU MAY 16 2013

THE STRONGEST PART OF THE ASCENT WITH THIS NEGATIVELY TILTED TROF
WILL BE RE-FOCUSING ON THE PLAINS SATURDAY EVENING. THIS SHOULD
ALLOW FOR A NOTICEABLE DOWNTURN TO THE CONVECTION AFTER SUNSET WITH
ISOLATED TO WIDELY SCATTERED STORMS LINGERING THROUGH THE MORNING
HOURS MAINLY OVER THE TERRAIN. THE STRONG RIDGING AHEAD OF THIS TROF
AND HIGH PRESSURE TO THE NORTH WILL ALLOW THE NEXT UPSTREAM SYSTEM
TO DIG INTO THE REAR OF THE LEAD TROF SUNDAY...EVENTUALLY FORMING A
REX LOW OVER THE UPPER MISSOURI VALLEY BY SUNDAY NIGHT. THIS
NORTHERN PLAINS LOW WILL BE SLOW TO MOVE EASTWARD AND WILL KEEP A
THREAT OF UNSETTLED WEATHER ACROSS THE EASTERN 2/3 OF OUR CWA GOING
INTO THE EARLY WEEK PERIOD.

COOLER AIR FILTERING INTO THE TROF SUNDAY WILL ALLOW FAIRLY
WIDESPREAD CONVECTION TO FORM OVER THE NORTHERN AND CENTRAL
MOUNTAINS SUNDAY AS THE ATMOSPHERE DESTABILIZES. QG FIELDS INDICATE
THE BETTER FORCING DROPPING INTO NORTHERN UTAH LATE IN THE DAY WHICH
WILL BE SWEEPING ACROSS COLORADO THROUGH THE EVENING. SUPPORTING
THIS WAVE WILL RIGHT EXIT REGION OF THE CYCLONIC JET WHICH SHOULD
KEEP SOME SHOWER ACTIVITY GOING ACROSS THE NORTHERN MOUNTAIN THROUGH
THE EARLY MORNING HOURS EVEN AS DRIER AIR BEGINS TO FILTER IN.
TEMPERATURES WILL COOLING OFF QUITE A BIT GOING INTO SUNDAY WITH
HIGHS RUNNING SOME 10 DEGREES OR SO BELOW NORMAL. H7 TEMPERATURES
LOWER TO NEAR FREEZING OVERNIGHT ACROSS THE NORTHERN COLORADO
MOUNTAIN WHICH MAY LEAVE SOME LIGHT SNOW ACCUMULATION ACROSS THE
HIGHER PEAKS...WITH LITTLE IMPACT TO THE PASSES EXPECTED.
CONVECTIVELY DRIVEN SHOWERS WILL PERSIST INTO MONDAY IN NORTHWEST
FLOW WITH COOL ADVECTION THROUGH THE DAY. TEMPERATURES WILL REMAIN
BELOW NORMAL UNDER THIS FLOW WITH WAA NOT MOVING UNTIL THE OVERNIGHT
HOURS.

TUESDAY SHOULD BE THE TRANSITION DAY BEFORE MUCH WARMER TEMPERATURES
AND DRIER CONDITIONS MOVE INTO THE REGION. A LARGER SYSTEM DROPPING
INTO THE PACIFIC NORTHWEST REGION WILL HELP PUSH A RIDGE BACK INTO
THE ROCKIES BY MID-WEEK BEFORE THE SOUTHWEST FLOW AHEAD OF THIS
FEATURE BUILDS IN BY THE LATE WEEK PERIOD. THIS SHOULD PUSH
TEMPERATURES BACK TO AND ABOVE NORMAL BY LATE WEEK. A TIGHTENING
PRESSURE GRADIENT AND STRONG MIXING MAY ONCE AGAIN BRING FIRE
WEATHER CONCERNS TO THE FOREFRONT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 355 PM MDT THU MAY 16 2013

VFR CONTINUES FOR MOST AREAS THOUGH A LINE OF STORMS AND SHOWERS
HAS FORMED JUST NORTH OF THE BOOKCLIFFS/TAVAPUTS FROM RANGELY
THROUGH MEEKER...INTO STEAMBOAT SPRINGS. ATTM...CIGS HOVER AROUND
7K TO 10K FEET WITH HEAVIER SHOWERS DROPPING VIS TO 3SM OR MVFR.
OUTFLOW WINDS UP TO 45 MPH HAVE ALSO BEEN REPORTED OVER KEEO SO
AREAS NEAR THIS LINE ALSO HAVE THE CHANCE FOR SEEING THESE GUSTY
WINDS. VFR WILL BECOME PREDOMINANT AFTER 03Z AND CONTINUE THROUGH
FRIDAY WITH SOME HIGH CLOUDS EXPECTED OVERNIGHT AND INTO TOMORROW
THOUGH SOME SCT CU CLOUDS ARE POSSIBLE OVER HIGHER TERRAIN.

&&

.FIRE WEATHER...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 PM MDT THU MAY 16 2013

STRONG HEATING THE NEXT FEW DAYS WILL COMBINE WITH STRONGER WINDS
ALOFT TO PRODUCE EFFICIENT MIXING PRODUCING GUSTY AFTERNOON WINDS.
RELATIVE HUMIDITY VALUES IN THE LOWER TEENS AND DRY FUELS WILL
COMBINE WITH THE STRONGER WINDS TO PRODUCE CRITICAL FIRE WEATHER
CONDITIONS DURING THE AFTERNOON AND EARLY EVENING HOURS TODAY AND
AGAIN ON FRIDAY. ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON
WILL ALSO BE CAPABLE OF PRODUCING STRONG OUTFLOW WINDS. THE DRIER
ATMOSPHERE ON FRIDAY SHOULD PROHIBIT THE THUNDERSTORM ACTIVITY. THE
WESTERN TROF WILL ARRIVE ON SATURDAY AND PRODUCE ACTIVE WEATHER
THROUGH EARLY NEXT WEEK BEFORE UPPER RIDGING MOVE BACK INTO THE
ROCKIES. COOLER WEATHER THIS WEEKEND WILL THEN GRADUALLY WARM THROUGH
NEXT WEEK WITH MAINLY DRY CONDITIONS EXPECTED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...RED FLAG WARNING FROM NOON TO 8 PM MDT FRIDAY FOR COZ203-207-290-
     292-293.

     RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ203-207-290-
     292.

UT...NONE.
&&

$$

SHORT TERM...TGR
LONG TERM...15
AVIATION...TGR
FIRE WX...15

000
FXUS65 KGJT 161734
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1134 AM MDT THU MAY 16 2013

.UPDATE...
ISSUED AT 1134 AM MDT THU MAY 16 2012

NO CHANGES TO FORECAST AS NORTHERN AREAS REMAIN FAVORED FOR
CONVECTION THIS AFTERNOON. THIS CONVECTION SHOULD START FIRING
OVER THE NEXT FEW HOURS. LESS CLOUD COVER WILL ALSO KEEP WARM
TEMPS GOING WITH HIGHS TODAY WELL ABOVE NORMAL VALUES FOR THIS
TIME OF YEAR.

&&

SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 250 AM MDT THU MAY 16 2013

SLIGHTLY STRONGER SOUTHWEST FLOW WILL BE IN PLACE TODAY WITH
ANOTHER ROUND OF DIURNALLY DRIVEN CONVECTION EXPECTED THIS
AFTERNOON. BULK OF ACTIVITY TODAY WILL BE CONFINED TO THE CENTRAL
AND NORTHERN ZONES WHERE BETTER MOISTURE RESIDES AND SLIGHTLY
BETTER WIND SHEER IN PLACE. SOUTHERN ZONES WILL SEE ISOLATED
CONVECTION...MAINLY ACROSS THE SAN JUANS. CONVECTIVE ACTIVITY
SHOULD FIRE BY 18Z OVER THE HIGHER TERRAIN AND CONTINUE THROUGH
THIS EVENING. HOWEVER...WITH NO APPARENT FORCING TONIGHT
THUNDERSTORMS WILL SHUT DOWN WITH SUNSET. THE RIDGE AXIS SHIFTS
EAST OVERNIGHT AND SW GRADIENT WINDS WILL INCREASE OVER HIGHER
TERRAIN PERHAPS BREAKING INVERSIONS ON THE NORTH FACING SLOPES.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL.

THE DEEP TROUGH WORKS INTO NEVADA ON FRIDAY. THE AIR MASS REMAINS
QUITE DRY AND INSUFFICIENT FOR CONVECTION. CONTINUED ABOVE NORMAL
AFTERNOON TEMPERATURES WILL PRODUCE MIXING TO AROUND 500MB WHERE SW
WINDS ARE PROGGED TO BE IN THE 30-35KT RANGE. THIS AGAIN RAISES FIRE
WEATHER CONCERNS.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 250 AM MDT THU MAY 16 2013

FRIDAY NIGHT-SATURDAY NIGHT...A STRONGER DISTURBANCE WORKS INTO THE
BOTTOM OF THE TROUGH AS IT PROGRESSES INTO UTAH GIVING IT A NEGATIVE
TILT. MOISTURE ALSO BEGINS TO INVADE FOR INCREASING CONVECTIVE
SHOWERS KEEPING TEMPERATURES MILD AGAIN OVERNIGHT. SATURDAY
AFTERNOON MAY SEE LOCALLY STRONG OUTFLOW WIND GUSTS. THE SUB-CLOUD
LAYER MOISTENS SATURDAY NIGHT FOR WIDESPREAD SHOWERS AS THE TROUGH
WORKS THROUGH THE FORECAST AREA.

THE UNSETTLED CONDITIONS LINGER INTO EARLY NEXT WEEK WITH THE
BROAD SCALE TROUGH OVER THE NORTHERN ROCKIES MAKING SLOW EASTWARD
PROGRESS. THIS WILL KEEP DIURNALLY DRIVE CONVECTION GOING SUNDAY
THROUGH TUESDAY...BEFORE RIDGING RETURNS AROUND MID WEEK.
TEMPERATURES WILL BE RUNNING NEAR SEASONAL NORMS THROUGH THIS
PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z NOON FRIDAY)
ISSUED AT 1134 AM MDT THU MAY 16 2013

WIDESPREAD VFR OCCURRING ATTM WITH SOME CLOUDS STARTING TO FORM
OVER THE HIGHER ELEVATIONS. SOME CONVECTION IS EXPECTED THIS
AFTERNOON BUT COVERAGE SHOULD BE LESS THAN YESTERDAY WITH THE
MOUNTAINS BEING FAVORED. NO MENTION OF STORMS OR SHOWERS IN TAFS
DUE TO WIDESPREAD NATURE OF PRECIP. VFR TO CONTINUE OVERNIGHT INTO
TOMORROW AS SW FLOW CONTINUES.

&&

.FIRE WEATHER...(TODAY THROUGH TUESDAY)
ISSUED AT 250 AM MDT THU MAY 16 2013

THE UPPER RIDGE WILL BREAK DOWN LATE TODAY AS A STRONGER PACIFIC
TROF WORKS THROUGH NEVADA. UPPER LEVEL WINDS WILL SHIFT TO SOUTHWEST
AND STRENGTHEN TODAY INTO FRIDAY. ABOVE NORMAL DAYTIME TEMPERATURES
WILL PRODUCE DRY AFTERNOON HUMIDITIES. OCCASIONAL WIND GUSTS UP TO
35 MPH WILL BE POSSIBLE ACROSS MOST OF THE VALLEYS OF WESTERN
COLORADO. CRITICAL FIRE WEATHER CONDITIONS WILL BE REALIZED WHERE
FUELS ARE DRY. SOME WEAK HUMIDITY RECOVERY IS EXPECTED TONIGHT...BUT
DRY AND WINDY CONDITIONS WILL REDEVELOP FRIDAY AFTERNOON. MOISTURE
INCREASES FRIDAY NIGHT THROUGH SATURDAY NIGHT AS THE TROUGH WORKS
THROUGH THE REGION. A COOL DOWN WITH THE TROF SHOULD EASE THE
CRITICAL FIRE WEATHER CONDITIONS. SOME SHOWERS WILL CONTINUE INTO
EARLY NEXT WEEK MAINLY ACROSS THE NORTHERN ZONES.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     FOR COZ203-207-290-292-293.

     RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ203-207-290-
     292.

UT...NONE.

&&

$$

UPDATE...TGR
SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...TGR
 FIRE WEATHER...JOE

000
FXUS65 KGJT 160851
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
251 AM MDT THU MAY 16 2013

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 250 AM MDT THU MAY 16 2013

SLIGHTLY STRONGER SOUTHWEST FLOW WILL BE IN PLACE TODAY WITH
ANOTHER ROUND OF DIURNALLY DRIVEN CONVECTION EXPECTED THIS
AFTERNOON. BULK OF ACTIVITY TODAY WILL BE CONFINED TO THE CENTRAL
AND NORTHERN ZONES WHERE BETTER MOISTURE RESIDES AND SLIGHTLY
BETTER WIND SHEER IN PLACE. SOUTHERN ZONES WILL SEE ISOLATED
CONVECTION...MAINLY ACROSS THE SAN JUANS. CONVECTIVE ACTIVITY
SHOULD FIRE BY 18Z OVER THE HIGHER TERRAIN AND CONTINUE THROUGH
THIS EVENING. HOWEVER...WITH NO APPARENT FORCING TONIGHT
THUNDERSTORMS WILL SHUT DOWN WITH SUNSET. THE RIDGE AXIS SHIFTS
EAST OVERNIGHT AND SW GRADIENT WINDS WILL INCREASE OVER HIGHER
TERRAIN PERHAPS BREAKING INVERSIONS ON THE NORTH FACING SLOPES.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL.

THE DEEP TROUGH WORKS INTO NEVADA ON FRIDAY. THE AIR MASS REMAINS
QUITE DRY AND INSUFFICIENT FOR CONVECTION. CONTINUED ABOVE NORMAL
AFTERNOON TEMPERATURES WILL PRODUCE MIXING TO AROUND 500MB WHERE SW
WINDS ARE PROGGED TO BE IN THE 30-35KT RANGE. THIS AGAIN RAISES FIRE
WEATHER CONCERNS.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 250 AM MDT THU MAY 16 2013

FRIDAY NIGHT-SATURDAY NIGHT...A STRONGER DISTURBANCE WORKS INTO THE
BOTTOM OF THE TROUGH AS IT PROGRESSES INTO UTAH GIVING IT A NEGATIVE
TILT. MOISTURE ALSO BEGINS TO INVADE FOR INCREASING CONVECTIVE
SHOWERS KEEPING TEMPERATURES MILD AGAIN OVERNIGHT. SATURDAY
AFTERNOON MAY SEE LOCALLY STRONG OUTFLOW WIND GUSTS. THE SUB-CLOUD
LAYER MOISTENS SATURDAY NIGHT FOR WIDESPREAD SHOWERS AS THE TROUGH
WORKS THROUGH THE FORECAST AREA.

THE UNSETTLED CONDITIONS LINGER INTO EARLY NEXT WEEK WITH THE
BROAD SCALE TROUGH OVER THE NORTHERN ROCKIES MAKING SLOW EASTWARD
PROGRESS. THIS WILL KEEP DIURNALLY DRIVE CONVECTION GOING SUNDAY
THROUGH TUESDAY...BEFORE RIDGING RETURNS AROUND MID WEEK.
TEMPERATURES WILL BE RUNNING NEAR SEASONAL NORMS THROUGH THIS
PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 250 AM MDT THU MAY 16 2013

VFR CONDITIONS WILL BE IN PLACE THIS MORNING...WITH CLOUDS ON THE
INCREASE STARTING AROUND 17Z WITH MORE AFTERNOON CONVECTION
FOR AREAS MOSTLY NORTH OF KGJT-KGUC. LOCAL -SHRA/-TSRA WILL BE
ENDING AROUND 03Z THIS EVENING WITH VFR CONDS EXPECTED AT ALL
SITES FOR THE REMAINDER OF THE NIGHT. GUSTY OUTFLOW WINDS...BRIEF
HEAVY RAINFALL AND SMALL HAIL WILL ACCOMPANY THE STRONGER STORMS.

&&

.FIRE WEATHER...(TODAY THROUGH TUESDAY)
ISSUED AT 250 AM MDT THU MAY 16 2013

THE UPPER RIDGE WILL BREAK DOWN LATE TODAY AS A STRONGER PACIFIC
TROF WORKS THROUGH NEVADA. UPPER LEVEL WINDS WILL SHIFT TO SOUTHWEST
AND STRENGTHEN TODAY INTO FRIDAY. ABOVE NORMAL DAYTIME TEMPERATURES
WILL PRODUCE DRY AFTERNOON HUMIDITIES. OCCASIONAL WIND GUSTS UP TO
35 MPH WILL BE POSSIBLE ACROSS MOST OF THE VALLEYS OF WESTERN
COLORADO. CRITICAL FIRE WEATHER CONDITIONS WILL BE REALIZED WHERE
FUELS ARE DRY. SOME WEAK HUMIDITY RECOVERY IS EXPECTED TONIGHT...BUT
DRY AND WINDY CONDITIONS WILL REDEVELOP FRIDAY AFTERNOON. MOISTURE
INCREASES FRIDAY NIGHT THROUGH SATURDAY NIGHT AS THE TROUGH WORKS
THROUGH THE REGION. A COOL DOWN WITH THE TROF SHOULD EASE THE
CRITICAL FIRE WEATHER CONDITIONS. SOME SHOWERS WILL CONTINUE INTO
EARLY NEXT WEEK MAINLY ACROSS THE NORTHERN ZONES.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
     FOR COZ203-207-290-292-293.

     RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 9 PM MDT THIS
     EVENING FOR COZ203-207-290-292.

UT...NONE.

&&

$$

SHORT TERM...JDC/JOE
LONG TERM...JOE/JDC
AVIATION...JDC
FIRE WEATHER...JOE

000
FXUS65 KGJT 160357
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
957 PM MDT WED MAY 15 2013

.UPDATE...
ISSUED AT 957 PM MDT WED MAY 15 2013

TIGHT CLOSED LOW CIRCULATION HAS MOVED OVER THE GRAND VALLEY THIS
EVENING...STILL TRIGGERING CONVECTIVE SHOWERS OVER NW COLORADO.
INTENSITY OF THESE SHOWERS WITH ISOLATED THUNDER GRADUALLY
DIMINISHING...BUT EXPECT SOME ACTIVITY TO CONTINUE THROUGH 09Z (3 AM).
BEFORE DAYBREAK...THE TIGHT CIRCULATIION WEAKENS AS IT CROSSES THE
DIVIDE. THE AREAL COVERAGE OF SHOWERS WILL SHRINK DURING THE
OVERNIGHT HOURS...EXPECT IT TO END BEFORE SUNRISE.

FOR ERN UTAH AND SOUTHWEST COLORADO...DRIER MID LEVEL AIR SPREADS
ACROSS THESE AREAS OVERNIGHT. CLEARING SKIES BECOMING CLEAR BEFORE
DAYBREAK. FORECAST GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT
CONDITIONS AND TRENDS.

&&

.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 358 PM MDT WED MAY 15 2013

WIDESPREAD CONVECTION HAS FIRED THIS AFTERNOON...AS EXPECTED...AS
AN APPROACHING DISTURBANCE PROVIDES WIDESCALE LIFT ON A RELATIVELY
MOIST ATMOSPHERE. ATTM...CONVECTION IS A MORE POP AND DROP TYPE
BUT AS THE DISTURBANCE CONTINUES TO GET CLOSER...SOME OF THE
STORMS MAY BECOME A BIT MORE INTENSE. THE MAIN CONCERN WITH THESE
STORMS WILL BE SOME PEA-SIZED HAIL AND ALSO SOME GUSTY OUTFLOW
WINDS POSSIBLY REACHING 40 MPH OR SO. THE STORMS ARE ALSO SLOW
MOVERS SO WILL KEEP AN EYE ON PRECIP AMOUNTS OVER THE MOUNTAINS
AND BURN SCARS WHERE MORE PRECIP WILL BE REACHING THE GROUND. THE
DISTURBANCE WILL MOVE OVER OUR FORECAST AREA FROM 9PM THROUGH 3AM
BEFORE FINALLY EXITING THE AREA. ALL SHORT-TERM MODELS INDICATING
A DOWNTURN IN PRECIP AND STORMS SHORTLY AFTER SUNSET WHICH
INDICATES SUPPORT FOR THE DISTURBANCE WILL WANE AND WEAKEN AS IT
PASSES OVER. FORECAST FOLLOWS SUIT WITH NO PRECIP EXPECTED AFTER
MIDNIGHT.

WESTERLY FLOW ALOFT BECOMES PREDOMINANTLY SOUTHWESTERLY THURSDAY
AHEAD OF A TROUGH THAT WILL COME ASHORE ALONG THE WESTERN COAST. A
110KT JET WILL BE DIGGING THIS TROUGH ON THURSDAY WHILE A WEAKER
JET STREAK WILL BE EXITING THE TROUGH AND MOVING OVER NV AND NRN
UT. THE STREAK WILL PROVIDE JUST ENOUGH SUPPORT...ALONG WITH SOME
OROGRAPHIC LIFT...TO FIRE OFF SOME MORE CONVECTION TOMORROW THOUGH
MODELS HINTING THAT BEST COVERAGE WILL BE NORTHERN THIRD OF THE
FORECAST AREA. SOME CONVECTION IS POSSIBLE BUT WILL BE ON THE WEAK
SIDE...IF IT OCCURS AT ALL...WITH SOME CU BUILDUP AND THE ODD SPOTTY
SHOWER EXPECTED. REMAINING AREAS WILL SEE TIMES OF SUN AND CLOUDS.
SOUTHWESTERLY FLOW WILL KEEP WARM TEMPERATURES IN PLACE CONTINUING
OUR WARM STRETCH. CONVECTION WILL DIE DOWN OVERNIGHT AS DAYTIME
HEATING ENDS LEAVING SOME HIGH LEVEL CLOUDS OVERNIGHT.

MODELS HAVE REALLY PULLED BACK ON PRECIP FOR FRIDAY AHEAD OF THE
TROUGH AS IT APPEARS THE JET DIGGING DOWN INTO THE TROUGH WILL
SLOW THE FORWARD MOVEMENT AND KEEP PRECIP OVER NV AND WRN UT. WENT
AHEAD AND DROPPED POPS IN OUR FORECAST UNTIL THE EVENING HOURS
EXCEPT FOR THE EASTERN UINTAS. EXPECT PRECIP TO START RAMPING UP
SATURDAY MORNING AS THE TROUGH BECOMES NEGATIVELY TILTED AND
BEGINS TO MOVE OVER THE FORECAST AREA.

.LONG TERM...(SATURDAY NIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 358 PM MDT WED MAY 15 2013

THE WESTERN TROF WILL BE TAKING ON SOMEWHAT OF A NEGATIVE TILT AS IT
MOVES INTO THE WESTERN GREAT BASIN SATURDAY AFTERNOON. MOISTURE
TRANSPORT VECTORS NEAR 315K INDICATE A RETURN OF MOISTURE OUT OF THE
BAJA REGION WITH PWATS PUSHING BACK TO NEAR NORMAL AFTER THE DRYING
OUT PERIOD ON FRIDAY. THE EURO/GFS STILL SOMEWHAT SPLIT ON ENERGY
DIVING INTO THE TROF WITH THE GFS CARRYING MORE ENERGY INTO THE BASE
OF THE TROF WITH THE MAIN AREA OF ASCENT MOVING SOUTH OF THE 4
CORNERS. THE EURO ON THE OTHER HAND IS MOVING A SLIGHTLY FLATTER
TROF WITH ASCENT LIFTING ACROSS THE NORTHERN CWA EARLIER IN THE
DAY THEN REFOCUSING IN THE EASTERN PLAINS. CONFIDENCE STILL LESS
THAN STELLAR GOING INTO THIS WEEKEND TO PICK OUT A FAVORED AREA TO
RECEIVE THE BETTER PRECIPITATION...SO ISOLATED TO SCATTERED POPS
WILL REMAIN IN PLACE. COOLING ALOFT ALONG WITH INCREASED CLOUD
COVER WILL BRING A DEFINITE COOL DOWN BUT THE MAIN BOUNDARY
ASSOCIATED WITH THE COLDER AIR DOES NOT LOOK TO PUSH THROUGH THE
CWA UNTIL SATURDAY EVENING. THIS MAY KEEP SOME ISOLATED NOCTURNAL
SHOWERS GOING THROUGH THE EARLY MORNING HOURS ON SUNDAY. SNOW
LEVELS MAY LOWER TO NEAR 9000 FEET ACROSS THE NORTHERN MOUNTAINS
OVERNIGHT BUT WITH LITTLE IMPACT EXPECTED. HIGHS ON SATURDAY WILL
BE KNOCKED DOWN BY 10 DEGREES OR SO ON SATURDAY TO MORE NORMAL
READINGS FOR MID-MAY.

BOTH MODELS SHOW A SECONDARY WAVE ROTATING IN THE BACK OF THE TROF
ON SUNDAY WITH THE COOLER AIR ALOFT LEADING TO UNSTABLE CONDITIONS
IN THE AFTERNOON. WITH DRIER AIR FILTERING IN MUCH OF THE FOCUS
SHOULD MAINLY BE ACROSS THE HIGHER TERRAIN OF THE CENTRAL AND
NORTHERN MOUNTAINS DUE TO JET DYNAMICS LIFTING NORTHWARD ACROSS THIS
REGION. BEYOND THIS PERIOD THE GFS AND EURO ARE KEEPING THEIR
STUBBORN SOLUTIONS GOING INTO THE EARLY WEEK PERIOD WITH THE EURO
WETTER ACROSS OUR NORTHERN MOUNTAINS AND SLOWER TO PUSH OUT THE TROF
UNTIL MID WEEK AND SEEMS THE WAY TO LEAN WITH THE NEGATIVE TILT TO
THIS SYSTEM. THIS WILL KEEP BELOW NORMAL TEMPERATURES IN PLACE
MONDAY WITH SOME SLOW WARMING GOING INTO THE MID WEEK PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 957 PM MDT WED MAY 15 2013

WIDESPREAD SHOWERS WITH ISOLATED -TSRA OVER NW COLORADO WILL BRING
IFR CIGS TO MOUNTAIN AIRPORTS. HOWEVER THIS ACTIVITY IS QUICKLY
WANING AND VFR WILL RETURN TO ALL TAF SITES BY 12Z.

EXPECT CLOUDS ON THE INCREASE STARTING AROUND 17Z WITH MORE AFTERNOON
CONVECTION POSSIBLE FOR AREAS MOSTLY NORTH OF KGJT-KGUC. LOCAL
-SHRA/-TSRA WILL BE ENDING AROUND 03Z.

&&

.FIRE WEATHER...(TONIGHT THROUGH TUESDAY)
ISSUED AT 358 PM MDT WED MAY 15 2013

THE UPPER RIDGE WILL BE BREAKING DOWN OVER THE NEXT FEW DAYS AS A
STRONGER PACIFIC TROF PROGRESSES INLAND INTO THE GREAT BASIN. UPPER
LEVEL WINDS WILL TURN MORE SOUTHERLY AND INCREASE THROUGH THE
REMAINDER OF THE WEEK. AS TEMPERATURES WARM INTO THE MID 80S
TOMORROW INTO FRIDAY AFTERNOON...WIND GUSTS IN THE 30 TO 40 MPH
RANGE WILL BE POSSIBLE OVER MUCH OF WESTERN COLORADO. FUELS REMAIN
CRITICAL ALONG THE THE GRAND VALLEY EASTWARD ALONG THE I-70
CORRIDOR BELOW 8000 FEET WHICH WILL COMBINE WITH RELATIVE HUMIDITY
READINGS IN THE LOWER TEENS AND GUSTY WINDS TO CREATE CRITICAL
FIRE WEATHER CONDITIONS. SOME RECOVERY OF THE HUMIDITY IS EXPECTED
THURSDAY NIGHT...WITH DRY AND WINDY CONDITIONS REDEVELOPING BY
FRIDAY AFTERNOON LEADING TO ANOTHER ROUND OF CRITICAL FIRE WEATHER
CONDITIONS. THE MAIN TROF WILL PUSH ACROSS THE REGION SATURDAY
INTO SUNDAY WITH SOME SHOWERS LINGERING ACROSS THE HIGHER TERRAIN
OF NORTHERN COLORADO INTO EARLY NEXT WEEK. A COOL DOWN WITH THE
TROF SHOULD EASE THE CRITICAL FIRE WEATHER CONDITIONS.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM 2 PM TO 9 PM MDT THURSDAY FOR COZ203.

UT...NONE.
&&

$$

UPDATE...PF
SHORT TERM...TGR
LONG TERM...15
AVIATION...PF
FIRE WEATHER...15

000
FXUS65 KGJT 152159
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
359 PM MDT WED MAY 15 2013

.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 358 PM MDT WED MAY 15 2013

WIDESPREAD CONVECTION HAS FIRED THIS AFTERNOON...AS EXPECTED...AS
AN APPROACHING DISTURBANCE PROVIDES WIDESCALE LIFT ON A RELATIVELY
MOIST ATMOSPHERE. ATTM...CONVECTION IS A MORE POP AND DROP TYPE
BUT AS THE DISTURBANCE CONTINUES TO GET CLOSER...SOME OF THE
STORMS MAY BECOME A BIT MORE INTENSE. THE MAIN CONCERN WITH THESE
STORMS WILL BE SOME PEA-SIZED HAIL AND ALSO SOME GUSTY OUTFLOW
WINDS POSSIBLY REACHING 40 MPH OR SO. THE STORMS ARE ALSO SLOW
MOVERS SO WILL KEEP AN EYE ON PRECIP AMOUNTS OVER THE MOUNTAINS
AND BURN SCARS WHERE MORE PRECIP WILL BE REACHING THE GROUND. THE
DISTURBANCE WILL MOVE OVER OUR FORECAST AREA FROM 9PM THROUGH 3AM
BEFORE FINALLY EXITING THE AREA. ALL SHORT-TERM MODELS INDICATING
A DOWNTURN IN PRECIP AND STORMS SHORTLY AFTER SUNSET WHICH
INDICATES SUPPORT FOR THE DISTURBANCE WILL WANE AND WEAKEN AS IT
PASSES OVER. FORECAST FOLLOWS SUIT WITH NO PRECIP EXPECTED AFTER
MIDNIGHT.

WESTERLY FLOW ALOFT BECOMES PREDOMINANTLY SOUTHWESTERLY THURSDAY
AHEAD OF A TROUGH THAT WILL COME ASHORE ALONG THE WESTERN COAST. A
110KT JET WILL BE DIGGING THIS TROUGH ON THURSDAY WHILE A WEAKER
JET STREAK WILL BE EXITING THE TROUGH AND MOVING OVER NV AND NRN
UT. THE STREAK WILL PROVIDE JUST ENOUGH SUPPORT...ALONG WITH SOME
OROGRAPHIC LIFT...TO FIRE OFF SOME MORE CONVECTION TOMORROW THOUGH
MODELS HINTING THAT BEST COVERAGE WILL BE NORTHERN THIRD OF THE
FORECAST AREA. SOME CONVECTION IS POSSIBLE BUT WILL BE ON THE WEAK
SIDE...IF IT OCCURS AT ALL...WITH SOME CU BUILDUP AND THE ODD SPOTTY
SHOWER EXPECTED. REMAINING AREAS WILL SEE TIMES OF SUN AND CLOUDS.
SOUTHWESTERLY FLOW WILL KEEP WARM TEMPERATURES IN PLACE CONTINUING
OUR WARM STRETCH. CONVECTION WILL DIE DOWN OVERNIGHT AS DAYTIME
HEATING ENDS LEAVING SOME HIGH LEVEL CLOUDS OVERNIGHT.

MODELS HAVE REALLY PULLED BACK ON PRECIP FOR FRIDAY AHEAD OF THE
TROUGH AS IT APPEARS THE JET DIGGING DOWN INTO THE TROUGH WILL
SLOW THE FORWARD MOVEMENT AND KEEP PRECIP OVER NV AND WRN UT. WENT
AHEAD AND DROPPED POPS IN OUR FORECAST UNTIL THE EVENING HOURS
EXCEPT FOR THE EASTERN UINTAS. EXPECT PRECIP TO START RAMPING UP
SATURDAY MORNING AS THE TROUGH BECOMES NEGATIVELY TILTED AND
BEGINS TO MOVE OVER THE FORECAST AREA.

.LONG TERM...(SATURDAY NIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 358 PM MDT WED MAY 15 2013

THE WESTERN TROF WILL BE TAKING ON SOMEWHAT OF A NEGATIVE TILT AS IT
MOVES INTO THE WESTERN GREAT BASIN SATURDAY AFTERNOON. MOISTURE
TRANSPORT VECTORS NEAR 315K INDICATE A RETURN OF MOISTURE OUT OF THE
BAJA REGION WITH PWATS PUSHING BACK TO NEAR NORMAL AFTER THE DRYING
OUT PERIOD ON FRIDAY. THE EURO/GFS STILL SOMEWHAT SPLIT ON ENERGY
DIVING INTO THE TROF WITH THE GFS CARRYING MORE ENERGY INTO THE BASE
OF THE TROF WITH THE MAIN AREA OF ASCENT MOVING SOUTH OF THE 4
CORNERS. THE EURO ON THE OTHER HAND IS MOVING A SLIGHTLY FLATTER
TROF WITH ASCENT LIFTING ACROSS THE NORTHERN CWA EARLIER IN THE
DAY THEN REFOCUSING IN THE EASTERN PLAINS. CONFIDENCE STILL LESS
THAN STELLAR GOING INTO THIS WEEKEND TO PICK OUT A FAVORED AREA TO
RECEIVE THE BETTER PRECIPITATION...SO ISOLATED TO SCATTERED POPS
WILL REMAIN IN PLACE. COOLING ALOFT ALONG WITH INCREASED CLOUD
COVER WILL BRING A DEFINITE COOL DOWN BUT THE MAIN BOUNDARY
ASSOCIATED WITH THE COLDER AIR DOES NOT LOOK TO PUSH THROUGH THE
CWA UNTIL SATURDAY EVENING. THIS MAY KEEP SOME ISOLATED NOCTURNAL
SHOWERS GOING THROUGH THE EARLY MORNING HOURS ON SUNDAY. SNOW
LEVELS MAY LOWER TO NEAR 9000 FEET ACROSS THE NORTHERN MOUNTAINS
OVERNIGHT BUT WITH LITTLE IMPACT EXPECTED. HIGHS ON SATURDAY WILL
BE KNOCKED DOWN BY 10 DEGREES OR SO ON SATURDAY TO MORE NORMAL
READINGS FOR MID-MAY.

BOTH MODELS SHOW A SECONDARY WAVE ROTATING IN THE BACK OF THE TROF
ON SUNDAY WITH THE COOLER AIR ALOFT LEADING TO UNSTABLE CONDITIONS
IN THE AFTERNOON. WITH DRIER AIR FILTERING IN MUCH OF THE FOCUS
SHOULD MAINLY BE ACROSS THE HIGHER TERRAIN OF THE CENTRAL AND
NORTHERN MOUNTAINS DUE TO JET DYNAMICS LIFTING NORTHWARD ACROSS THIS
REGION. BEYOND THIS PERIOD THE GFS AND EURO ARE KEEPING THEIR
STUBBORN SOLUTIONS GOING INTO THE EARLY WEEK PERIOD WITH THE EURO
WETTER ACROSS OUR NORTHERN MOUNTAINS AND SLOWER TO PUSH OUT THE TROF
UNTIL MID WEEK AND SEEMS THE WAY TO LEAN WITH THE NEGATIVE TILT TO
THIS SYSTEM. THIS WILL KEEP BELOW NORMAL TEMPERATURES IN PLACE
MONDAY WITH SOME SLOW WARMING GOING INTO THE MID WEEK PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 358 PM MDT WED MAY 15 2013

WIDESPREAD CONVECTION WILL CONTINUE THROUGH 03Z AND THEN DIE DOWN
AS DAYTIME HEATING ENDS. ALL TAF SITES WILL SEE VCTS WITH KASE AND
KEGE SEEING TSTORMS THIS AFTN. GUSTY SFC WINDS WILL BE BIGGEST
CONCERN WITH SOME BRIEF MVFR ALSO POSSIBLE UNDER THE HEAVIER
SHOWERS. REMAINING AREAS SHOULD SEE PLENTY OF VFR WITH SCT TO BKN
SKIES BEING COMMON. AFTER 03Z...VFR WILL BE THE RULE AS A FEW HIGH
CLOUDS PERSIST OVERNIGHT AND INTO TOMORROW. EXPECT CLOUDS ON THE
INCREASE STARTING AROUND 17Z WITH MORE AFTERNOON CONVECTION
POSSIBLE FOR AREAS MOSTLY NORTH OF I-70.

&&

.FIRE WEATHER...(TONIGHT THROUGH TUESDAY)
ISSUED AT 358 PM MDT WED MAY 15 2013

THE UPPER RIDGE WILL BE BREAKING DOWN OVER THE NEXT FEW DAYS AS A
STRONGER PACIFIC TROF PROGRESSES INLAND INTO THE GREAT BASIN. UPPER
LEVEL WINDS WILL TURN MORE SOUTHERLY AND INCREASE THROUGH THE
REMAINDER OF THE WEEK. AS TEMPERATURES WARM INTO THE MID 80S
TOMORROW INTO FRIDAY AFTERNOON...WIND GUSTS IN THE 30 TO 40 MPH
RANGE WILL BE POSSIBLE OVER MUCH OF WESTERN COLORADO. FUELS REMAIN
CRITICAL ALONG THE THE GRAND VALLEY EASTWARD ALONG THE I-70
CORRIDOR BELOW 8000 FEET WHICH WILL COMBINE WITH RELATIVE HUMIDITY
READINGS IN THE LOWER TEENS AND GUSTY WINDS TO CREATE CRITICAL
FIRE WEATHER CONDITIONS. SOME RECOVERY OF THE HUMIDITY IS EXPECTED
THURSDAY NIGHT...WITH DRY AND WINDY CONDITIONS REDEVELOPING BY
FRIDAY AFTERNOON LEADING TO ANOTHER ROUND OF CRITICAL FIRE WEATHER
CONDITIONS. THE MAIN TROF WILL PUSH ACROSS THE REGION SATURDAY
INTO SUNDAY WITH SOME SHOWERS LINGERING ACROSS THE HIGHER TERRAIN
OF NORTHERN COLORADO INTO EARLY NEXT WEEK. A COOL DOWN WITH THE
TROF SHOULD EASE THE CRITICAL FIRE WEATHER CONDITIONS.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...RED FLAG WARNING FROM 2 PM TO 9 PM MDT THURSDAY FOR COZ203.

UT...NONE.
&&

$$

SHORT TERM...TGR
LONG TERM...15
AVIATION...TGR
FIRE WEATHER...15