000
FXUS65 KGJT 210852
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
252 AM MDT TUE MAY 21 2013

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 218 AM MDT TUE MAY 21 2013

TODAY
AREAS OF MID LEVEL MOISTURE STILL STREAMING ACROSS OUR
CWA...THOUGH EXPECT A GRADUAL EROSION OF THE MOISTURE FROM THE
WEST TODAY. HOWEVER...DAYTIME HEATING STILL EXPECTED TO GENERATE
SOME RELATIVELY WEAK CONVECTION AGAIN...MAINLY OVER MOUNTAINS...
THOUGH PRECIPITATION SHOULD BE MINIMAL. ALTHOUGH TODAY SHOULD BE
NOTICEABLY WARMER THAN YESTERDAY...STILL HAVE ONE MORE DAY WITH
MAX TEMPERATURES BELOW NORMAL FOR MANY LOCATIONS MAINLY N OF
I-70...WHILE S OF I-70 EXPECT TEMPERATURES CLOSER TO NORMAL.

TONIGHT
THE HIGH PRESSURE RIDGE AXIS WILL PASS OVERHEAD TONIGHT. ONE WEAK
EMBEDDED WAVE WILL PASS THROUGH THE RIDGE AND INTO EASTERN UT THIS
EVENING...THEN EXIT ACROSS THE CONTINENTAL DIVIDE LATE TONIGHT.
THE LIMITED MOISTURE ASSOCIATED WITH THIS WAVE WILL BE MID TO HIGH
BASED...SO DO NOT SEE MORE THAN AN ISOLATED SHOWER OR TWO OVER THE
HIGHEST TERRAIN. OTHERWISE ANY MOUNTAIN CONVECTION LEFT OVER FROM
THE AFTERNOON WILL QUICKLY DIMINISH AS DAYTIME HEATING SUBSIDES.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 218 AM MDT TUE MAY 21 2013

WEDNESDAY-THURSDAY
THE FLOW ALOFT BECOMES SOUTHWEST ON WED AS A LOW PRESSURE SYSTEM
STRENGTHENS OVER THE PACIFIC NORTHWEST. THE FLOW WILL INCREASES
WED NIGHT INTO THURSDAY AS A SHORTWAVE ROTATES AROUND THE
LOW...TIGHTENING THE PRESSURE GRADIENT OVER OUR FORECAST AREA.
CONDITIONS WILL CONTINUE TO WARM...WITH THE WARMING TREND QUITE
STEEP THROUGH WED. AND WILL BE MOST PRONOUNCED OVER THE NORTH
WHERE HIGHS WILL BE UP TO 15 DEGREES WARMER THAN TODAY`S. BUT ALL
LOCATIONS WILL SEE WELL ABOVE NORMAL TEMPERATURES WED AFTERNOON.
THE TREND WILL FLATTEN OUT SOMEWHAT BY THU WITH ANOTHER COUPLE
DEGREES OF WARMING. THE GOOD DAYTIME HEATING WILL PRODUCE A DEEP
MIXED LAYER BOTH DAYS. THIS WILL ALLOW A FEW SOUTHWEST GUSTS ON
WED...BUT BY THU AFTERNOON THE STRONGER FLOW WILL MIX TO THE
SURFACE. IN ADDITION TO THE WARMER CONDITIONS...THE SOUTHWEST FLOW
WILL BRING DRIER AIR OVER THE AREA. FIRE WEATHER CONCERNS DEVELOP
WITH THIS SCENARIO BY THU AS THE GUSTY WINDS COMBINE WITH LOW
RELATIVE HUMIDITY. SEE FIRE WEATHER DISCUSSION BELOW.

THURSDAY NIGHT THROUGH MONDAY
PRESENTLY...NOT MUCH CHANGE EXPECTED THROUGH THIS PERIOD FROM THE
PREVIOUS DAY...UNDER A PERSISTENT AND DRY SOUTHWEST FLOW ALOFT.
MAX TEMPERATURES SHOULD REMAIN ABOVE NORMAL...AS THE PREVIOUS
COUPLE OF DAYS. AND ALTHOUGH PREDOMINANT SOUTHERLY SURFACE WINDS
EXPECTED EACH DAY...THOSE WINDS ARE NOT EXPECTED TO BE AS STRONG
AS ON THURSDAY AFTERNOON...THUS RESULTING IN A LESSENED THREAT FOR
FIRE WEATHER CONCERNS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 218 AM MDT TUE MAY 21 2013

SOME ISOLATED SHOWERS THIS MORNING...AND THEN ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON AND
EARLY EVENING MAINLY OVER THE HIGHER MOUNTAINS OF WESTERN COLORADO
AND NORTHEAST UTAH...WITH MOUNTAIN TOPS LOCALLY OBSCURED. ISOLATED
SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP WEDNESDAY AFTERNOON
OVER THE SAME HIGHER MOUNTAIN AREAS OF WESTERN COLORADO AND
NORTHEAST UTAH. OTHERWISE VFR CONDITIONS EXPECTED TO PREVAIL
ACROSS THE AREA THROUGH THE REMAINDER OF THIS WEEK.

&&

.FIRE WEATHER...
ISSUED AT 218 AM MDT TUE MAY 21 2013

AS THE RIDGE SHIFTS EASTWARD...IT WILL PULL VERY DRY AND WARM AIR IN
FROM THE SOUTHWEST BEGINNING TODAY. AS TEMPERATURES SURPASS SEASONAL
NORMALS WED AND THU AFTERNOONS...RELATIVE HUMIDITY VALUES ARE
EXPECTED TO DROP INTO THE SINGLE DIGITS OVER THE LOWER ELEVATIONS OF
SOUTHWEST AND WEST CENTRAL CO. ALSO BY WEDNESDAY THE FLOW WILL
BECOME MORE SOUTHWEST...AND THEN INCREASE ON THU. DUE TO GOOD
DAYTIME HEATING A DEEP MIXED LAYER WILL DEVELOP WITH THE STRONG FLOW
ALOFT MIXING TO THE SURFACE ON THU AFTERNOON. THESE GUSTY SOUTHWEST
WINDS...IN COMBINATION WITH THE DRY AIR MASS MAY PRODUCE CRITICAL
FIRE CONDITIONS. THEREFORE A FIRE WEATHER WATCH WILL BE ISSUED WITH
THIS PACKAGE FOR THE LOWER ELEVATIONS OF WEST CENTRAL AND SOUTHWEST
CO FOR THU AFTERNOON AND EARLY EVENING. THE POTENTIAL FOR CONTINUED
FIRE WEATHER CONCERNS WILL PERSIST TROUGH THE REMAINDER OF THE WEEK
AS LOW PRESSURE PERSISTS OVER THE PACIFIC NORTHWEST.

&&

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

UT...NONE.
&&

$$

SHORT TERM...EH/JRP
LONG TERM...JRP
AVIATION...JRP
FIRE WEATHER...EH