000
FXUS65 KGJT 172135
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
335 PM MDT THU MAY 17 2012

.SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 335 PM MDT THU MAY 17 2012

WEAK DIURNAL CONVECTION OVER THE HIGHER TERRAIN THIS AFTERNOON
WILL CONTINUE DRIFTING EAST AND WILL BE DISSIPATING BY MID
EVENING. BULK OF STORMS WILL PRODUCE GUSTY WINDS AND LITTLE
RAINFALL...WITH ACTIVITY MAINLY CONFINED TO THE HIGHER TERRAIN.
BREAK IN THE ACTION THEN MOVES IN OVERNIGHT.

ON FRIDAY...A STRONG COLD FRONT WILL BE PUSHING EAST ACROSS THE
GREAT BASIN. THIS WILL BRING ANOTHER WINDY DAY ALONG WITH DRY
CONDITIONS RESULTING IN CRITICAL FIRE WEATHER CONDITIONS. THIS IS
DISCUSSED IN MORE DETAIL BELOW. IN ADDITION TO THE INCREASE
WINDS...THE FRONT WILL USHER IN A LINE OF LATER DAY SHOWERS AND
THUNDERSTORMS. INITIALLY...THESE WILL BE HIGH BASED...ENHANCING
WIND GUST POTENTIAL THROUGHOUT THE REGION. LOCAL GUSTS OVER 50 MPH
WILL BE POSSIBLE. THE SHOWERS AND THUNDERSTORMS WILL BECOME BETTER
PRECIPITATION PRODUCERS AS THE FRONT SLIDES THROUGH AND BETTER LOW
LEVEL MOISTURE SLIGHT IN. CONVECTION DIMINISHES FROM WEST TO EAST
BY MIDNIGHT FRIDAY NIGHT...WITH SKIES CLEARING AFTER MIDNIGHT.

TEMPS WILL CONTINUE RUNNING SLIGHTLY ABOVE SEASONAL NORMS THROUGH
FRIDAY AFTERNOON...BEFORE THE COOLER AIR ASSOCIATED WITH THE FRONT
DRIVES READINGS DOWN TO BELOW NORMAL FRIDAY NIGHT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 335 PM MDT THU MAY 17 2012

THE TROF AXIS WILL BE MOVING EAST OF THE ROCKIES BY SATURDAY MORNING
LEAVING A COOL NORTHWESTERLY FLOW IN IT/S WAKE. THIS WILL LEAD TO
SOME INSTABILITY/OROGRAPHIC SHOWERS MAINLY ACROSS THE NORTHERN HALF
OF THE CWA ON SATURDAY. THERE IS A SMALL HINT OF A SURFACE
CONVERGENT LINE DRAPED ACROSS THE NORTHERN VALLEYS AS RE-ENFORCED
COOL AIR LEAKS IN AND THIS MAY ALLOW SOME OF THE SHOWERS TO REACH
THE VALLEY FLOORS...BUT FOR THE MOST PART THE DENDRITIC LAYER WILL
BE DRYING OUT SO POPS REMAIN ON THE VERY LOW SIDE. TEMPERATURES OF 5
TO 10 DEGREES COOLER...ESPECIALLY NORTH...CAN BE EXPECTED ON
SATURDAY BEHIND THIS FRONT WITH HIGHS ACTUALLY FALLING BELOW NORMAL
OVER MANY PLACES FOR MID MAY.

THE LEAD TROF WILL PROGRESS INTO THE PLAINS ON SATURDAY NIGHT INTO
SUNDAY AND EVENTUALLY PHASE WITH LOW PRESSURE OVER THE SOUTHEAST
STATES EARLY NEXT WEEK. AS THIS HAPPENS ENERGY WILL BE CONGEALING
ACROSS THE NORTHEAST PACIFIC BEFORE ARRIVING TO THE NORTHWEST COAST
BY MONDAY. WITH LOW PRESSURE IN THESE AREAS...DRY RIDGING WILL
SETTLE OVER THE INTER-MOUNTAIN WEST AND ROCKIES AND BRING A RETURN TO
WARMER...ABOVE NORMAL TEMPERATURES. WINDS LOOK TO BE FAIRLY LIGHT
WITH MIXING LEADING TO SOME AFTERNOON GUSTINESS IN PLACES SO THIS
WILL LIMIT THE CRITICAL FIRE WEATHER THREAT. HOWEVER AS THE WESTERN
TROF BEGINS TO MOVE INLAND ON TUESDAY...THE GRADIENT WINDS WILL ONCE
AGAIN TIGHTEN AND FIRE CONCERNS WILL RETURN TO THE FOREFRONT. ONE
CAVEAT HOWEVER IS MODEL AGREEMENT WITH THE STRENGTH AND TIMING OF
THIS TROF. THE FLATTER...HENCE MORE PROGRESSIVE EURO SOLUTION IS
BACKED BY THE DAMPENED OUT ENSEMBLE FORECASTS...WITH THE GFS TAKING
THE SLOWER MORE AMPLIFIED SOLUTION THE PAST FEW RUNS. THE TROF
PASSAGE WILL LEAD TO A PERIOD OF UNSETTLED WEATHER...BUT HOW
EXTENSIVE OF COVERAGE TO THIS CWA IS UNCERTAIN ATTM SO THE BLENDED
MODEL OUTPUT OF SMALL POPS WILL SUFFICE FOR NOW.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 335 PM MDT THU MAY 17 2012

SCATTERED SHOWERS AND THUNDERSTORMS WILL COME TO AN END BY 03Z
THIS EVENING. LOCAL AREAS OF MVFR CIGS CAN BE EXPECTED IN THE
VCNTY OF THE SHOWERS WITH MOUNTAIN TOPS BECOMING BRIEFLY OBSCURED.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL DEVELOP BY MIDDAY
FRIDAY WITH GUSTY SOUTHWEST WINDS ALSO DEVELOPING AS A COLD FRONT
APPROACHES FROM THE WEST. THIS FRONT WILL BRING A SUDDEN SHIFT IN
WINDS TO THE NORTHWEST AFTER 00Z SATURDAY.

&&

.FIRE WEATHER...
ISSUED AT 335 PM MDT THU MAY 17 2012

A STRONG TROUGH WILL APPROACH THE AREA LATE TONIGHT AND FRIDAY.
STRONG SOUTHWEST WINDS ALOFT AND AT THE SURFACE WILL DEVELOP BY LATE
FRIDAY MORNING AND CONTINUE INTO THE EVENING...COMBINING WITH
VERY DRY CONDITIONS AS TEMPERATURES ONCE AGAIN PUSH WELL ABOVE
NORMAL. THIS COMBINATION OF WINDS AND HUMIDITY SHOULD REACH RED
FLAG CRITERIA OVER MUCH OF WESTERN COLORADO WHERE FUELS ARE IN A
READY TO BURN STATE. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM
SHOULD PASS THROUGH WESTERN EARLY FRIDAY EVENING...CAUSING A
DISTINCT WIND SHIFT TO THE NORTHWEST. COOLER AND CALMER CONDITIONS
CAN BE EXPECTED ON SATURDAY TO HELP ALLEVIATE THE FIRE DANGER.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM 11 AM TO 10 PM MDT FRIDAY FOR COZ201-203-
     207-290-292-293.

UT...NONE.
&&

$$

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

NWS GJT Office Area Forecast Discussion