000
FXUS65 KGJT 121011
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
411 AM MDT SUN MAY 12 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 411 AM MDT SUN MAY 12 2013

A SHORTWAVE TROUGH IN THE NORTHWESTERLIES WAS MOVING THROUGH
CENTRAL COLORADO GENERATING SOME LIGHT SHOWERS OVER THE HIGHER
ELEVATIONS. SHOWERS WERE HIGH BASED BASED ON CIG HEIGHTS FROM AREA
SURFACE OBSERVATIONS AND THE 00Z/SUN KGJT SOUNDING. THIS FEATURE
WILL MOVE INTO SOUTHERN COLORADO AROUND SUNRISE SO ADDED SO LOW
POPS TO THE SOUTHWEST SAN JUAN MOUNTAINS. GIVEN THE LACK OF
MOISTURE IN THE LOWER LEVELS EXPECT LOWER ELEVATIONS WILL
EXPERIENCE ONLY VIRGA.

TEMPERATURES WILL CONTINUE TO INCREASE TODAY AS HIGH PRESSURE TO
THE WEST EASES TOWARD THE AREA DRIVING HIGHS ABOVE NORMAL AND
DELIVERING THE WARMEST DAY OF THE YEAR. MOISTURE CIRCULATING
BENEATH THE HIGH WILL FUEL WIDELY SCATTERED MOUNTAIN THUNDERSTORMS
AS THE AIRMASS WARMS AND DESTABILIZES DURING THE AFTERNOON. STORMS
WILL BE MAINLY CONFINED TO THE RANGES OF THE CONTINENTAL DIVIDE.

UPPER RIDGE OVER OUR CWA SUNDAY NIGHT AND MONDAY...WITH WARMING
TREND CONTINUING. MAX TEMPERATURES ON MONDAY SHOULD BE 10-15
DEGREES ABOVE NORMAL ACROSS OUR CWA. HEATING OF THE DAY SHOULD
HELP INDUCE A LITTLE CONVECTION FROM RESIDUAL MID LEVEL MOISTURE
MAINLY OVER MOUNTAINS MONDAY AFTERNOON. ANY THUNDERSTORMS OR
SHOWERS THAT DEVELOP SHOULD BE HIGH BASED WITH MINIMAL
PRECIPITATION REACHING THE GROUND.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 411 AM MDT SUN MAY 12 2013

UPPER RIDGE OVER OUR AREA EXPECTED TO BE MOVING EASTWARD MONDAY
NIGHT IN RESPONSE TO A PACIFIC SHORTWAVE TROUGH WHICH SHOULD
FLATTEN THE RIDGE AND HAVE OUR CWA UNDER A WESTERLY FLOW ALOFT ON
TUESDAY. COLD FRONT ASSOCIATED WITH THE SHORTWAVE TROUGH LIKELY TO
PENETRATE THE NW CORNER OF OUR CWA BY LATE TUESDAY AFTERNOON...
PROBABLY JUST AS FAR AS THE EASTERN UINTAH MOUNTAINS. HOWEVER...
EXACT TIMING OF THE FRONT MOVING INTO OUR CWA STILL SOMEWHAT
UNCERTAIN AS MODELS PRESENTING DIFFERENT SOLUTIONS. BREEZY SURFACE
WINDS LIKELY TO DEVELOP MAINLY NORTHERN ZONES BY TUESDAY AFTERNOON
IN RESPONSE TO THE BAROCLINIC BOUNDARY IN CLOSE PROXIMITY TO OUR
NORTHERN BORDER. FOR MOST LOCATIONS IN OUR CWA...MAX TEMPERATURES
ON TUESDAY NOT LIKELY TO BE MUCH DIFFERENT THAN MONDAY. AND RH
VALUES...AT LEAST IN THE NORTHERN LOWER ELEVATION ZONES LIKELY TO
DROP DOWN TO 15 PERCENT OR LESS TUESDAY AFTERNOON. SITUATION NEEDS
MONITORING FOR POTENTIAL FIRE WEATHER CONCERNS. A FEW HIGH-BASED
SHOWERS OR THUNDERSTORMS POSSIBLE AGAIN TUESDAY AFTERNOON MAINLY
OVER MOUNTAINS DUE PRIMARILY TO DAYTIME HEATING.

MODELS INDICATED THE SHORTWAVE DRIVING THE COLD FRONT WILL PUSH
TO THE EAST TUESDAY NIGHT LEAVING THE FRONT STALLED ACROSS THE
NORTH ON WEDNESDAY. BY WEDNESDAY AFTERNOON...THE BAROCLINIC ZONE
WILL HAVE WASHED OUT...BUT COOLER AIR WILL REMAIN RESULTING IN
SLIGHTLY MILDER TEMPERATURES. SUFFICIENT MOISTURE EXISTS FOR
ANOTHER ROUND OF DIURNAL SHOWERS AND THUNDERSTORMS...MAINLY OVER
THE MOUNTAINS.

FLOW BACKS TO THE SOUTHWEST BRINGING A BIT OF DRYING ON THURSDAY
AND FRIDAY THOUGH A FEW AFTERNOON/EVENING THUNDERSTORMS ARE
POSSIBLE OVER THE HIGH COUNTRY. WINDS PICK UP FRIDAY AFTERNOON AS
A PACIFIC TROUGH SHIFTS INLAND DRIVING A COLD FRONT TOWARD
NORTHEAST UTAH. LOW RH...WARMER THAN NORMAL DAYTIME TEMPERATURES AND
BREEZY WINDS COULD RESULT IN CRITICAL FIRE WEATHER CONDITIONS FOR
MUCH OF EASTERN UTAH AND WESTERN COLORADO FRIDAY AFTERNOON.

THOUGH TIMING DIFFERS BETWEEN THE GFS AND THE EC...BOTH INDICATED
COOLER AND WETTER CONDITIONS SATURDAY AS THE PACIFIC TROUGH MOVES
ACROSS THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 411 AM MDT SUN MAY 12 2013

A WEAK DISTURBANCE WILL CONTINUE TO GENERATE ISOLATED LIGHT
SHOWERS OVER THE REGION THROUGH 18Z SUNDAY. HOWEVER...THIS
ACTIVITY WILL NOT BE STRONG ENOUGH TO LOWER FLIGHT CATEGORIES
BELOW VFR. FROM 18Z TO 03Z...DAYTIME HEATING WILL RESULT IN
ISOLATED THUNDERSTORMS OVER THE MOUNTAINS ALONG THE DIVIDE.
EXCEPT FOR LOCALIZED MOUNTAIN OBSCURATIONS...VFR CONDITIONS
WILL CONTINUE. SHOWERS AND THUNDERSTORMS WILL DIMINISH AFTER
03Z MONDAY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

$$

SHORT TERM...NL/JRP
LONG TERM...NL/JRP
AVIATION...NL