993
FXUS65 KGJT 221749
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1149 AM MDT WED MAY 22 2013
.UPDATE...
ISSUED AT 1149 AM MDT WED MAY 22 2013
SOUNDING A LITTLE DRIER AND WARMER TODAY WITH CU NOT QUITE AS
ROBUST LATE THIS MORNING AS DAYS PAST. THERE IS AN UPSTREAM WAVE
MOVING ACROSS NEVADA INTO SOUTHERN UTAH WHICH WILL ARRIVE HERE
DURING PEAK HEATING. SOME MOISTURE ADVECTION IN THE UPPER LEVELS
IS INDICATED AND PERHAPS SOME WEAK UPPER DIVERGENCE IN THE
SOUTHERN MOUNTAINS NEAR A WEAKER BRANCH OF THE SUB TROPICAL JET.
GOING FORECAST MAINLY ON TRACK FOR ISOLATED TO SCATTERED STORMS
CLOSER TO THE DIVIDE WITH A FEW STAY SHOWERS FARTHER OUT ON THE
SAN JUANS AND POSSIBLY THE EASTERN UTAH MOUNTAINS. TEMPERATURE
STILL ON TRACK TO BE AROUND 10 DEGREES WARMER THAN YESTERDAY. THE
STRONG MIXING WILL BRING SOME GUSTY WINDS POSSIBLY DURING THE LATE
PEAK HEATING TIME IN THE WESTERN CWA...PUSHING SOME LOCALLY
CRITICAL FIRE WEATHER CONDITIONS FOR AN HOUR OR TWO ACROSS THE
SOUTHERN VALLEYS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 156 AM MDT WED MAY 22 2013
TODAY
SCREAMING MESSAGE TODAY IS THE SIGNIFICANT WARMING EXPECTED AS
SOUTHWESTERLY FLOW ADVECTS WARMER AIR INTO OUR AREA. MAX
TEMPERATURES TODAY AT MOST LOCATIONS SHOULD BE ABOUT 10 DEGREES F
WARMER THAN YESTERDAY...WHILE H7 TEMPERATURES ARE PROGGED TO BE 4
TO 5 DEGREES C WARMER THAN YESTERDAY. ALSO EXPECT BREEZY SOUTH TO
SOUTHWEST WINDS ACROSS MUCH OF OUR CWA BY THIS AFTERNOON.
A LITTLE MID AND HIGH LEVEL MOISTURE OVER THE AREA TODAY...THOUGH
THE AIRMASS WILL BE A LITTLE DRIER THAN YESTERDAY. HOWEVER...DUE
TO DAYTIME HEATING THERE STILL EXISTS THE POSSIBILITY FOR ISOLATED
HIGH-BASED SHOWERS AND THUNDERSTORMS BY THIS AFTERNOON MAINLY OVER
MOUNTAINS ALONG/NEAR CONTINENTAL DIVIDE AND PERHAPS ALSO OVER THE
EASTERN UINTA MOUNTAINS.
TONIGHT
A MILD NIGHT IS IN STORE AS THE RIDGE AXIS WILL BE OVER EASTERN CO.
THE SOUTHWEST FLOW ALOFT WILL STRENGTHEN AS A STRONG LOW PRESSURE
SYSTEM DEVELOPS OVER THE PACIFIC NORTHWEST. A SMATTERING OF CLOUDS
AND WARM TEMPERATURES ALOFT WILL KEEP LOWS ABOVE NORMAL.
THURSDAY
THE SOUTHWEST FLOW CONTINUES TO INCREASE AS SHORTWAVE ENERGY
ROTATES AROUND THE PACIFIC NORTHWEST LOW. THIS DRY WAVE WILL BRUSH
OUR WESTERN EDGE THU AFTERNOON/EVENING AND TIGHTEN THE PRESSURE
GRADIENT ACROSS THE REGION. DEEP AFTERNOON MIXING FUELED BY THE
VERY WARM TEMPERATURES WILL ALLOW THE STRONGER WINDS ALOFT TO MIX
TO THE SURFACE. THE WARM TEMPERATURES AND THE LACK OF ANY MOISTURE
WITH THE WAVE WILL DRIVE RELATIVE HUMIDITY VALUES INTO THE SINGLE
DIGITS ACROSS MUCH OF THE SOUTHERN AND CENTRAL PORTIONS OF THE
FORECAST AREA...ESPECIALLY IN THE LOWER ELEVATIONS. THE
COMBINATION OF THE STRONG WINDS AND LOW RELATIVE HUMIDITY WILL
PRODUCE CRITICAL FIRE WEATHER CONDITIONS WHERE FUELS ARE DRY. SEE
FIRE WEATHER DISCUSSION BELOW.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 156 AM MDT WED MAY 22 2013
THURSDAY NIGHT-FRIDAY
WINDS WILL REMAIN GUSTY UNTIL HEATING SUBSIDES THURSDAY EVENING.
ALSO IN PLAY WILL BE THE EXITING OF THE SHORTWAVE AXIS TO THE
NORTH BY MID TO LATE EVENING FROM SOUTH TO NORTH. HOWEVER EXPECT
THAT THE DIURNAL DECOUPLING OF THE AIR MASS WILL BE A STRONGER
INFLUENCE THAN THE TIMING OF THE WAVE DURING THE
EVENING...ESPECIALLY FOR THE LOWER ELEVATIONS. OVERNIGHT LOW
TEMPERATURES WILL BE A LITTLE COOLER IN THE WAKE OF THE SHORTWAVE.
THE GRADIENT RELAXES SOMEWHAT ON FRIDAY. BUT THE LARGE SCALE PATTERN
REMAINS IN PLACE AS THE FORECAST AREA SITS BETWEEN THE NORTHWEST LOW
AND HIGH PRESSURE OVER THE PLAINS STATES. HOWEVER WITHOUT ANOTHER
SHORTWAVE EXPECT WINDS WILL BE A NOTCH LOWER...IN SPITE OF SOME
AFTERNOON GUSTS. THIS SCENARIO WILL HAVE TO BE WATCHED FOR FIRE
WEATHER CONCERNS. FOR NOW WINDS SEEM TO MAINLY STAY BELOW CRITERIA.
TEMPERATURES REMAIN A FEW DEGREES LOWER THAN THOSE ON THU.
FRIDAY NIGHT THROUGH MEMORIAL DAY
FOR ALL PRACTICAL PURPOSES...LITTLE CHANGE EXPECTED AS PERSISTENT
DRY SOUTHWEST FLOW ALOFT WILL CONTINUE OVER OUR CWA. TEMPERATURES
SHOULD REMAIN SEVERAL DEGREES ABOVE NORMAL. ALSO EXPECT BREEZY
SOUTH TO SOUTHWEST WINDS FOR SOME LOCATIONS TO OCCUR EACH
AFTERNOON.
MONDAY NIGHT AND TUESDAY
MODELS BRING A PACIFIC SHORTWAVE TROUGH INLAND DURING THIS TIME
FRAME. GFS...WHICH IS FASTER THAN EC...BRINGS THE TROUGH TO OUR
CWA BY TUESDAY. FOR NOW...ONLY HAVE SLIGHT CHANCE SHOWERS AND
THUNDERSTORMS FOR THE EASTERN UINTA MOUNTAINS ON TUESDAY...WHICH
IS PROBABLY SUFFICIENT FOR NOW SINCE THERE IS NOT A LOT OF
CONFIDENCE ON THE TIMING. ALSO EXPECT MAX TEMPERATURES TO DROP
DOWN TO NEAR NORMAL TUESDAY AS HEIGHTS/THICKNESS LOWER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1058 AM MDT WED MAY 22 2013
VFR CONDITIONS WILL REMAIN IN PLACE ACROSS EASTERN UTAH AND
WESTERN COLORADO OVER THE NEXT 24 HOURS. UNSTABLE CONDITIONS AND A
BIT OF MOISTURE OVER THE DIVIDE MOUNTAINS OF COLORADO WILL FORM
SOME AFTERNOON AND EARLY EVENING CONVECTION. GUSTY WINDS WILL BE
THE MAIN THREAT TO THE KEGE AND KASE TERMINALS...HOWEVER LIMITED
FLIGHT CRITERIA ARE NOT ANTICIPATED AT THIS TIME. SOUTHWEST WINDS
WILL BE INCREASING OVERNIGHT INTO THURSDAY AND MAY BRING LOCAL LOW
LEVEL WIND SHEAR IN THE MORNING HOURS DUE TO DOWN VALLEY FLOW.
FREQUENT WIND GUSTS OVER 25 MPH CAN BE EXPECTED BY EARLY THURSDAY
AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 218 AM MDT TUE MAY 21 2013
SOUTHWEST FLOW WILL STRENGTHEN THROUGH THURSDAY AS THE AREA SITS
BETWEEN A HIGH PRESSURE RIDGE TO OUR EAST...AND A STRONG LOW
PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST.
TODAY GUSTY WINDS WILL DEVELOP IN THE AFTERNOON...BUT GUSTS 25 MPH
OR ABOVE ARE NOT EXPECTED TO BE WIDESPREAD. AND IF THEY DO DEVELOP
THEY WILL GENERALLY BE LOCALIZED AND FOR A RELATIVELY SHORT
DURATION. THE AIR MASS WILL CONTINUE TO DRY AS WARMING CONTINUES.
BY THURSDAY...THE SOUTHWEST FLOW INCREASES AS A DISTURBANCE
ROTATING AROUND THE PACIFIC NORTHWEST LOW BRUSHES THE FORECAST
AREA. DEEP MIXING IN THE AFTERNOON WILL ALLOW THE STRONG SOUTHWEST
WINDS TO MIX TO THE SURFACE. RELATIVE HUMIDITY VALUES WILL DROP
INTO THE SINGLE DIGITS ACROSS THE LOWER SOUTHWEST AND WEST CENTRAL
VALLEYS. WHERE FUELS ARE DRY...WIND GUSTS 25-35 MPH IN THE LOWER
ELEVATIONS WILL COMBINE WITH THE DRY CONDITIONS TO PRODUCE
CRITICAL FIRE WEATHER CONDITIONS THU AFTERNOON AND EVENING.
THEREFORE A RED FLAG WARNING WILL CONTINUE TO BE IN EFFECT FOR THE
LOWER ELEVATIONS OF CO FIRE ZONES 207...290...292 AND 293.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM NOON TO 9 PM MDT THURSDAY FOR COZ207-290-
292-293.
UT...NONE.
&&
$$
UPDATE...15
SHORT TERM...EH/JRP
LONG TERM...EH/JRP
AVIATION...TGJT
FIRE WEATHER...EH
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