Red Flag Warning 11, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
350 AM MST SUN MAY 23 2010

.SYNOPSIS...EXPECT VERY WINDY AND COOLER CONDITIONS TODAY AS A
POWERFUL STORM SYSTEM MOVES TOWARD WESTERN ARIZONA. AREAS OF BLOWING
SAND AND DUST ARE LIKELY EAST AND NORTHEAST OF FLAGSTAFF BY THIS
AFTERNOON. THIS STORM WILL BRING A CHANCE OF RAIN AND SNOW SHOWERS
TO PORTIONS OF FAR NORTHERN ARIZONA LATER TODAY AND TONIGHT...ALONG
WITH FREEZING TEMPERATURES ABOVE 6000 FEET. LIGHTER WINDS AND SLOWLY
WARMING TEMPERATURES WILL RETURN FOR MUCH OF NEXT WEEK.

&&

.DISCUSSION...AN UNSEASONABLY COLD AND DEEP TROUGH WILL MOVE INTO
WESTERN ARIZONA THIS AFTERNOON...AND WILL THEN LIFT NORTHEAST INTO
SOUTHERN UTAH TONIGHT. THIS TROUGH HAS -7C AIR AT 700 MB IN THE CORE
WHILE EASTERN ARIZONA REMAINS AT AROUND +8C TO +9C AT 700 MB. THIS
IS A TREMENDOUS THERMAL GRADIENT FOR THIS TIME OF YEAR...AND WE
EXPECT STRONG WINDS AS A RESULT. WIND ADVISORIES ARE OUT IN MOST
ZONES TODAY...WITH THE LCR AND VICINITY UPGRADED TO A HIGH WIND
WARNING. THIS WILL BE A PROLIFIC DUST PRODUCER EAST AND NORTHEAST OF
FLAGSTAFF...AND WE HAVE ALSO ISSUED A DUST STORM WARNING.

THIS SYSTEM IS MOISTURE-STARVED...BUT SO MUCH FORCING EXISTS ALONG
THE FRONT...COUPLED WITH SOME INSTABILITY THIS EVENING...THAT A FEW
RAIN AND SNOW SHOWERS WILL DEVELOP. THE BEST CHANCE FOR THIS WILL BE
LATE TODAY AND TONIGHT...MAINLY OVER NORTHERN ARIZONA.

BY MONDAY...MUCH LESS WIND IS EXPECTED BEHIND THE FRONT...ALTHOUGH
COOLER AIR WILL REMAIN IN PLACE. RISING HGHTS WILL STABILIZE THE
AIRMASS...AND ANY THREAT FOR PRECIPITATION SHOULD END. THE REMAINDER
OF THE WEEK FEATURES WARMER TEMPERATURES AND MAINLY DRY CONDITIONS
WITH NORMAL DIURNAL BREEZES. PERSISTENT SOUTHERN FLOW FROM AN
OFFSHORE TROUGH WILL EVENTUALLY BRING SOME MID-LEVEL MOISTURE INTO
THE STATE...AND A SLIGHT CHANCE OF SHOWERS MAY DEVELOP BY NEXT
WEEKEND.

&&

.AVIATION...FOR THE 12Z PACKAGE...VERY STRONG SOUTHWEST WINDS WILL
RE-DEVELOP BY 15Z-17Z TODAY...WITH SPEEDS OF 25-35KT GUSTING TO
40-50KT. OTHERWISE VFR CONDITIONS WILL PREVAIL...EXCEPT OVER EAST
CENTRAL AND NORTHEAST AZ WHERE BLOWING DUST WILL CAUSE REDUCED
VISIBILITY BELOW 1/4SM OVER A LARGE AREA...AND LOCALLY DOWN TO NEAR
ZERO. DECREASING WINDS ARE FORECAST AFTER 02Z MONDAY. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.DISCUSSION...A STRONG PACIFIC LOW PRESSURE SYSTEM WILL CONTINUE TO
AFFECT NORTHERN ARIZONA TODAY...BRINGING STRONG WINDS AND LOW
RELATIVE HUMIDITIES. WHILE RELATIVE HUMIDITIES WILL BE SLIGHTLY
HIGHER ACROSS MOST OF NORTHERN ARIZONA TODAY DUE TO LOWER AFTERNOON
TEMPERATURES...SOME AREAS WILL STILL EXPERIENCE CRITICAL FIRE
WEATHER CONDITIONS FROM LATE THIS MORNING THROUGH THIS EVENING. ON
MONDAY...CONDITIONS WILL REMAIN DRY WITH MINIMUM RELATIVE HUMIDITIES
BETWEEN 10-15 PERCENT...HOWEVER THE WINDS WILL BE MUCH LIGHTER AND
CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED.

TUESDAY THROUGH THURSDAY...WILL SEE GRADUAL WARMING AND
DRYING...ALONG WITH INCREASING SOUTH TO SOUTHWEST WINDS THROUGH THE
PERIOD.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

HIGH WIND WARNING FROM 7 AM MST UNTIL 7 PM MST TODAY AZ ZONES
012>014-040.

WIND ADVISORY FROM 7 AM MST UNTIL 7 PM MST TODAY AZ ZONES
004>011-015>018-037>039.

DUST STORM WARNING FROM 10 AM MST UNTIL 7 PM MST TODAY AZ ZONES
009-010-011-012-013-015-039-040.

RED FLAG WARNING FROM 10 AM MST UNTIL 7 PM MST FGZ FWX ZONES
110>114-137-140.

&&

PUBLIC..................PETERSON
AVIATION/FIRE WEATHER...JVC

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
908 PM MST SAT MAY 22 2010

AZZ004>018-037>040-230730-
KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY-
COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS-
NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY-
CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS-
NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS-
OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA-
NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-
908 PM MST SAT MAY 22 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
ARIZONA...NORTH CENTRAL ARIZONA...NORTHEAST ARIZONA AND WEST
CENTRAL ARIZONA.

.DAY ONE...TONIGHT

STRONG SOUTHWEST WINDS HAVE DECREASED THIS EVENING AND THE WIND
ADVISORY WAS ALLOWED TO EXPIRE AT 9 PM MST. STRONG WIND GUSTS ARE
LIKELY TO CONTINUE IN A LOCALIZED AREA NEAR DONEY PARK EAST OF
FLAGSTAFF THIS EVENING WITH GUSTS FROM 40 TO 50 MPH.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY

WINDY WEATHER WILL CONTINUE ON SUNDAY. A WIND ADVISORY HAS BEEN
ISSUED FOR ALL AREAS ON SUNDAY...SEE PHXNPWFGZ FOR DETAILS. EXPECT
BLOWING DUST AND SAND ACROSS NORTHEASTERN ARIZONA WHICH WILL LIMIT
VISIBILITIES ON AREA ROADWAYS TO NEAR ZERO AT TIMES. COLDER
TEMPERATURES WILL ALSO ARRIVE SUNDAY WITH A SLIGHT CHANCE OF RAIN
AND SNOW SHOWERS FROM FLAGSTAFF NORTHWARD INTO SUNDAY NIGHT. A
FIRE WEATHER WATCH HAS ALSO BEEN ISSUED FOR SUNDAY ACROSS PORTIONS OF
OUR LOWER ELEVATION ZONES...SEE PRODUCT PHXRFWFGZ FOR DETAILS.

WIND SPEEDS WILL DECREASE IN INTENSITY NEXT WEEK AS THE MAIN LOW
PRESSURE SYSTEM MOVES NORTHEASTWARD...AWAY FROM ARIZONA.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.