Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 021000
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
400 AM MDT SUN AUG 2 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 400 AM MDT SUN AUG 2 2015

TODAY IS ON TRACK TO BE A WET DAY ACROSS MUCH OF EASTERN UTAH AND
WESTERN COLORADO...THOUGH AREAS NORTH OF THE TAVAPUTS/BOOKCLIFFS
REGION ARE NOT LIKELY TO GET SOAKED UNTIL THE WEATHER SYSTEM
LIFTING NORTH THROUGH THE REGION TODAY REACHES THE NORTHERN AREAS TONIGHT
AND INTO MONDAY. A 500 MB CLOSED LOW DEVELOPS OVER SOUTHERN NEVADA
TODAY WITH AN ELOGATED VORT MAX STRETCHING EAST INTO SOUTHWEST
COLORADO. AS THIS ENERGY MOVES THROUGH THE ALREADY MOISTURE-PRIMED
FOUR CORNERS REGION...COMBINED WITH CLEARER SKIES THAN EXPECTED
OVERNIGHT...A LOT OF ACTIVITY IS EXPECTED TODAY FROM SOUTH TO
NORTH. THE CLOUD COVER BEING SLIM THIS MORNING WAS A MAJOR FACTOR
IN THE DECISION TO ISSUE FLASH FLOOD WATCHES FOR TODAY. BY THIS
EVENING...THE RAP13 AND NAM FORECAST MODELS INDICATE A WEAK
CIRCULATION DEVELOPING NEAR THE FOUR CORNERS WHICH INDICATES THIS
ENERGY WILL PROVIDE PLENTY OF DYNAMICS FOR HEAVY RAIN. THE ENERGY
SLOWLY MOVES NORTH THROUGHOUT THE DAY AND INTO THE OVERNIGHT
HOURS. THOUGH SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SOMEWHAT
DIMINISH DURING THE OVERNIGHT HOURS...BY MONDAY MORNING A WELL
DEFINED CIRCULATION LOOKS TO PRESENT ITSELF OVER EASTERN UTAH.
THIS CIRCULATION WILL PROVIDE LIFT TO THE ANTECEDENT MOISTURE AND
CREATE A BUSY DAY ACROSS NE UTAH AND NW COLORADO.

BIGGEST CHALLENGE AT THIS POINT IS HOW FAR THE HEAVIEST RAIN WILL
REACH TODAY AND THEN WHERE IT WILL FIRE BACK UP ON MONDAY. LOOKING
AT VERTICAL PROFILES...STEERING WINDS WILL REMAIN QUITE LOW TODAY
AND VARY BASED ON THE DEVELOPING WEAK CIRCULATIONS EMBEDDED ALOFT.
MID LEVEL WINDS DO INCREASE ON MONDAY SO FLASH FLOODING WILL NOT
LIKELY BE AS BIG OF AN ISSUE BUT WE WILL NEED TO WATCH THE
INCREASING VERTICAL SHEAR FOR OTHER POTENTIAL ISSUES ON
MONDAY...INCLUDING HAIL AND STRONG WINDS FROM THUNDERSTORMS.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 400 AM MDT SUN AUG 2 2015

SHORT WAVE WILL BE SLIDING DOWNSTREAM BY MONDAY NIGHT...BUT THERE
IS A SECONDARY BUT WEAKER UPPER LEVEL WAVE THAT LIFTS NORTHEAST
ACROSS NE UTAH AND WRN COLORADO TUESDAY AFTERNOON. COMBINED WITH
SOME CONVECTIVE POTENTIAL...SHOWERS/STORMS WILL POP AGAIN OVER THE
WESTERN COLORADO HIGH COUNTRY. PRECIPITABLE WATER WILL BE UNDER AN
INCH AND TRENDING LOWER...SO SHOWERS/STORMS WILL NOT HAVE THE
SAME INTENSITY.

SUBTROPICAL HIGH OVER THE SWRN CONUS RECOVERS AND DOMINATE THE
PATTERN...AT LEAST UNTIL FRIDAY. MOSTLY DRY WEATHER IS EXPECTED
WEDNESDAY AND THURSDAY...ALTHOUGH A LATE DAY MOUNTAIN STORM CAN
NOT BE COMPLETELY RULED OUT.

THE HIGH CORE REPOSITIONS ITSELF A TAD EAST AND ALLOWS FOR THE
MONSOONAL MOISTURE PLUME TO SURGE NORTH BEGINNING ON
FRIDAY...ALTHOUGH THE DEEPER MOISTURE MAY NOT ARRIVE UNTIL
SATURDAY. THE TREND WILL BE FOR INCREASING SHOWERS/STORMS FROM THE
SOUTH AT THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1152 PM MDT SAT AUG 1 2015

SCATTERED -SHRA WITH EMBEDDED TSRA WILL CONTINUE OVERNIGHT OVER SW
COLORADO. SOME NOCTURNAL STORMS WILL SPILL INTO SE UTAH. SHOWERS
AND STORMS WILL EXPAND ACROSS THE ENTIRE REGION ON SUNDAY
AFTERNOON...SHOWERS BECOMING NUMEROUS SOUTH OF I-70. THE STRONGEST
CELLS WILL PRODUCE 4SM +TSRA CIGS BKN030. ILS CIGS AND OBSCURATIONS
WILL BE COMMON AT MOUNTAIN TAF SITES AS SHOWERS/STORMS MOVE OVERHEAD.
SHOWERS WILL CONTINUE INTO SUNDAY EVENING. WITH SHORT WAVE PASSING
THROUGH UTAH AND COLORADO ON SUNDAY...CONVECTIVE CELLS WILL BE
LONGER LIVED AND MERGERS MAY OCCUR TO ENHANCE +SHRA WITH FREQUENT
LIGHTNING.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH FROM 10 AM MDT THIS MORNING THROUGH THIS
     EVENING FOR COZ006>012-014-017>023.

UT...FLASH FLOOD WATCH FROM 10 AM MDT THIS MORNING THROUGH THIS
     EVENING FOR UTZ022-027>029.

&&

$$

SHORT TERM...JAM
LONG TERM...PF
AVIATION...PF



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