606
FXUS65 KGJT 032057
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
255 PM MDT THU JUL 3 2008
SHORT TERM...TONIGHT THROUGH SATURDAY
HIGH PRESSURE COVERS UTAH AND COLORADO AND THIS WILL CONTINUE
THROUGH INDEPENDENCE DAY. TERRAIN AND DIURNALLY DRIVEN ISOLATED
STORMS HAVE DEVELOPED THIS AFTERNOON AND EXPECT SIMILAR CONDITIONS
FOR THE HOLIDAY. WATER VAPOR REVEALS THE AIR MASS IS DRIER OVER THE
NORTHWEST HALF OF THE FORECAST AREA...THE MAIN REASON THAT CONVECTIVE
ACTIVITY HAS BEEN SLOWER TO DEVELOP OVER THE NRN MOUNTAINS. ONE
SUBTLE CHANGE FOR FRIDAY...PRECIPITABLE WATER IN THE MODEL DATA
RISES A NOTCH OVER THE FOUR CORNERS. THE SOURCE OF THE MOISTURE
INCREASE COMING FROM THUNDERSTORM OUTFLOWS FROM NORTH CENTRAL NEW
MEXICO THIS AFTERNOON. THUNDERSTORM COVERAGE MAY INCREASE A NOTCH
FRIDAY AFTERNOON/EVENING FOR THE SRN ZONES...BUT MOS POP GUIDANCE
DOES NOT SHOW MUCH OF AN INCREASE. INCREASED THE COVERAGE OF SLIGHT
CHANCE POPS...BUT DID NOT RAISE ANY VALUES INTO THE CHANCE
CATEGORY. WITH THE WARMEST 700 MB TEMPS SO FAR...INDEPENDENCE DAY
MAY BE THE HOTTEST DAY SO FAR THIS SUMMER.
RIDGE WEAKENS ON SATURDAY AS PACIFIC NORTHWEST SHORT WAVE SKIRTS
ACROSS THE NRN TIER STATES. THE TAIL END OF THIS WAVE MOVES ACROSS
WRN COLORADO DURING THE PEAK HEATING HOURS. AS MENTIONED IN THE
PREVIOUS PARAGRAPH...PRECIPITABLE WATER WILL HAVE INCREASED AHEAD OF
THIS SHORT WAVE. WATER VAPOR SHOWS BORIS GETTING ENTRAINED INTO THE
SOUTHWEST FLOW AHEAD OF THIS SHORT WAVE...NOT SURE IF MODELS HAVE
PICKED UP ON THIS MOISTURE PLUME THAT IS EVIDENT IN THE WATER VAPOR.
BUT THE GFS AND WRF HAVE INCREASED CONVECTIVE PCPN...ESPECIALLY THE
SAN JUAN MOUNTAINS...FOR SATURDAY AFTERNOON. SO HAVE INCREASED POPS
OVER THE SRN AND CENTRAL MOUNTAINS WITH CHANCE POPS WHERE MOISTURE
WILL BE MORE READILY AVAILABLE AS COMPARED TO THE NRN MOUNTAINS. WITH
INCREASED CLOUD COVER...AFTERNOON TEMPERATURES WILL BE A LITTLE
COOLER THAN THE FOURTH OF JULY.
LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
SATURDAY NIGHT THROUGH MONDAY...STILL LOOKS LIKE WESTERLY FLOW TO THE
NORTH OF OUR CWA DURING THIS PERIOD IN RESPONSE TO A COUPLE OF
SHORTWAVE PACIFIC TROUGHS THAT WILL SUPPRESS THE UPPER HIGH INTO AZ
AND NM. THIS SHOULD BE A DRIER PATTERN FOR OUR CWA...AND NOT QUITE
AS WARM AS WE ARE CURRENTLY EXPERIENCING. STILL MAY HAVE ISOLATED
DIURNALLY-DRIVEN THUNDERSTORMS OVER THE MOUNTAINS OF OUR CWA SUNDAY
AND MONDAY...THOUGH EXPECT BY MONDAY THAT THEY WILL BE CONFINED TO
WESTERN SAN JUAN MOUNTAINS.
TUESDAY THROUGH THURSDAY...RESURGENCE OF STRONG UPPER RIDGE
EXPECTED OVER THE AREA WITH UPPER HIGH CENTER MIGRATING NORTHWARD.
WE SHOULD SEE TEMPERATURES 5-10F ABOVE NORMAL AGAIN...GENERALLY
AROUND 100F EACH DAY IN THE CLIMATOLOGICALLY WARMER AREAS OF OUR CWA
WITH SOME OF THE HOTTEST LOCATIONS IN SE UT REACHING THE 105F MARK.
THERE ARE INDICATIONS FOR A LITTLE INCREASE IN CONVECTIVE CLOUD
DEVELOPMENT BY WEDNESDAY OR THURSDAY. BUT STILL LOOKS TO BE GENERALLY
DRY WITH ONLY HIGH-BASED THUNDERSTORMS.
AVIATION
ISOLATED THUNDERSTORMS WILL CONTINUE INTO EARLY
EVENING...WITH MOST STORMS DISSIPATING BY 04Z. A FEW STORMS WILL
DRIFT OVER THE LOWER VALLEYS. EXPECT LOCAL MVFR VIS AND CIGS NEAR
SOME STORMS...MAINLY OVER THE MOUNTAINS. GUSTY THUNDERSTORM OUTFLOW
WINDS EXPECTED IN THE LOWER VALLEYS. OTHERWISE...VFR CONDITIONS TO
PREVAIL THROUGH TONIGHT. EXPECT SIMILAR CONDITIONS ON JULY 4TH.
HYDROLOGY
MOUNTAIN SNOWPACK CONTINUES TO DWINDLE AND RUNOFF WILL GRADUALLY
DECREASE RESULTING IN A SLOW LOWERING OF RIVER AND STREAM FLOWS
THROUGH THE WEEK. ALTHOUGH WATER LEVELS ARE DECREASING FLOWS REMAIN
COLD...SWIFT...AND TURBULENT. CAUTION IS URGED WHEN AROUND RIVERS
AND STREAMS.
GJT WATCHES/WARNINGS/ADVISORIES
CO
NONE.
UT
NONE.
SHORT TERM.....PF
LONG TERM......JRP
AVIATION.......TAL
HYDROLOGY......TGJT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page