High Wind and Winter Weather in Arizona, March 21 to 22, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 AM MST MON MAR 21 2011

.SYNOPSIS...A PACIFIC STORM SYSTEM AND COLD FRONT WILL MOVE ACROSS
ARIZONA TODAY BRINGING STRONG WINDS...RAIN AND SNOW...AND COLDER
TEMPERATURES TO THE REGION. FAIR WEATHER WILL RETURN STARTING LATE
TUESDAY...WITH BREEZY CONDITIONS FOR THE LATTER HALF OF THE WEEK.

&&

.DISCUSSION...A LONG WAVE TROUGH OVER THE WEST COAST WILL CONTINUE TO
PROGRESS EASTWARD BRINGING A SIGNIFICANT CHANGE TO THE WEATHER ACROSS
NRN AZ TODAY AND TONIGHT.

MILD TEMPS AND MOSTLY CLOUDY SKIES HAVE CONTINUED OVERNIGHT. WINDY
CONDITIONS WILL BE POSSIBLE THIS MORNING OVER LOCALIZED DOWNSLOPE
REGIONS...INCLUDING THE HIGHWAY 89 CORRIDOR FROM DONEY PARK TO GRAY
MOUNTAIN...AND A WIND ADVISORY REMAINS IN EFFECT FOR THIS AREA
THROUGH 11 AM THIS MORNING.

THE MAIN IMPACT FROM THIS STORM SYSTEM WILL BE TODAY AS THE TROUGH
MOVES TOWARD ARIZONA...PUSHING A STRONG FRONTAL PCPN BAND INTO
YAVAPAI/COCONINO COUNTIES JUST AFTER SUNRISE...PROGRESSING INTO ERN
AZ BY LATE AFTERNOON AND EARLY EVENING. THE STRONGEST WINDS TODAY ARE
EXPECTED ACROSS NAVAJO AND APACHE COUNTIES. THESE AREAS HAVE BEEN
PLACED UNDER A WIND ADVISORY. A HIGH WIND WARNING HAS ALSO BEEN
ISSUED FOR THE LCR PORTION OF THESE COUNTIES INCLUDING WINSLOW...
PETRIFIED FOREST...HOLBROOK AND ST JOHNS.

THE HEAVIEST PCPN AMOUNTS ARE STILL EXPECTED TO FAVOR AREAS ALONG AND
SOUTH OF THE MOGOLLON RIM...WITH LIQUID EQUIVALENT AMOUNTS RANGING
FROM 1/2 TO 3/4 INCHES ALONG THE MOGOLLON RIM...AND 3/4 TO 1 INCH IN
THE UPSLOPE AREAS SOUTH OF THE RIM. ELSEWHERE...AMOUNTS WILL
GENERALLY BE LESS THAN 1/4 INCH. THE MAIN PRECIP BAND IS EXPECTED TO
REACH WRN YAVAPAI/COCONINO COUNTIES AROUND SUNRISE...THE FLAGSTAFF
REGION MID TO LATE MORNING AND ERN AZ IN THE LATE AFTERNOON. THE
HEAVIEST PCPN IS EXPECTED TO LAST ONLY A FEW HOURS AT ANY GIVEN
LOCATION...THEN BECOME MORE SHOWERY INTO THE EVENING AS THE TROUGH
AXIS PASSES THROUGH.

SNOW LEVELS WILL FALL TO NEAR 5000-5500 FEET AS THE FRONTAL PCPN
BAND PASSES THROUGH. CURRENT SFC OBS...RADAR...AND SATELLITE IMAGERY
SHOW A SIGNIFICANT PLUME OF PACIFIC MOISTURE MOVING NORTHEASTWARD
ACROSS SRN CALIF..BAJA...AND INTO AZ THIS MORNING. THIS SHOULD
QUICKLY REPLACE THE DRY BOUNDARY LAYER AIRMASS CURRENTLY RESIDING
ACROSS AZ. THE RESULT IS THAT AS PCPN FIRST FALLS EVAPORATIONAL
COOLING INTO THE DRY AIR WILL BRIEFLY LOWER SNOW LEVELS BELOW WHAT
WOULD OTHERWISE BE EXPECTED BUT AS THE AIR MASS RAPIDLY MOISTENS SNOW
LEVELS WILL MOVE BACK UP. THUS...COULD BRIEFLY SEE SNOW MUCH BELOW
THE SNOW LEVELS GIVEN ABOVE BUT NO ACCUMULATION IS EXPECTED AT THESE
LOWER ELEVATIONS.

WITH THE HEAVIEST PCPN FALLING DURING DAYTIME AND EARLY EVENING
HOURS...SNOWFALL JUST ABOVE THE SNOW LEVEL MAY HAVE A TOUGH TIME
ACCUMULATING BECAUSE OF THE WARM GROUND. NONETHELESS...IT APPEARS
3 TO 6 INCHES ARE POSSIBLE ABOVE 6500 FEET WITH 8 TO 12 INCHES ABOVE
9000 FEET.

FAIR WEATHER WITH COOLER TEMPS EXPECTED LATE TUESDAY THROUGH
WEDNESDAY. ANOTHER S/W TROUGH WILL PASS ACROSS OR JUST NORTH OF THE
AREA EARLY THURSDAY. WILL CONTINUE TO INCLUDE A SLIGHT CHANCE OF
SHOWERS THROUGH MIDDAY THURSDAY. FAIR WEATHER RETURNS FOR A FEW
DAYS...THEN MODELS SUGGEST ANOTHER FAST MOVING TROUGH WILL PASS
ACROSS THE AREA EARLY NEXT WEEKEND.

&&

.AVIATION...FOR THE 12Z PACKAGE...A STORM SYSTEM WILL MOVE ACROSS
ARIZONA TODAY. OVERCAST MID-TO-UPPER LEVEL CLOUDINESS WILL BLANKET
NORTHERN PORTIONS OF THE STATE...WITH RAIN AND SNOW DEVELOPING IN
WEST AND CENTRAL ARIZONA BY EARLY TO MID MORNING. THE PRECIPITATION
WILL SPREAD EASTWARD THROUGH THE DAY. EXPECT LOCAL IFR/LIFR
CONDITIONS IN AREAS OF HEAVIER PRECIPITATION. STRONG SOUTHWEST WINDS
WILL DEVELOP THIS AFTERNOON. IN NORTHEASTERN ARIZONA...LOCAL GUSTS
MAY EXCEED 50 KTS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY REMAINS IN EFFECT
UNTIL 11 AM MST FOR AZZ015.

HIGH WIND WARNING REMAINS IN EFFECT FROM 8 AM UNTIL 6 PM MST FOR
AZZ013-014.

WIND ADVISORY REMAINS IN EFFECT FROM 8 AM UNTIL 6 PM MST MONDAY FOR
AZZ009>012-016-017-039-040.

&&

PUBLIC................DB
AVIATION..............HOWARD

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
400 AM MST MON MAR 21 2011

AZZ004>018-037>040-220700-
WESTERN MOGOLLON RIM-GRAND CANYON COUNTRY-YAVAPAI COUNTY MOUNTAINS-
YAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONS-
MARBLE AND GLEN CANYONS-KAIBAB PLATEAU-COCONINO PLATEAU-
NORTHEAST PLATEAU AND MESAS HWY 264 NORTHWARD-
NORTHEAST PLATEAU AND MESAS SOUTH OF HWY 264-
CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
BLACK MESA AREA-LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
EASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTY-
400 AM MST MON MAR 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...NORTHERN
GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN ARIZONA.

.DAY ONE...TODAY

A STRONG LOW PRESSURE SYSTEM AND COLD FRONT WILL MOVE ACROSS THE
REGION TODAY THROUGH EARLY TUESDAY MORNING BRINGING A SIGNIFICANT
CHANGE TO THE WEATHER ACROSS NORTHERN ARIZONA.

A WIND ADVISORY HAS BEEN ISSUED FOR MUCH OF EASTERN ARIZONA FOR WIND
GUSTS OF 40 TO 50 MPH. A HIGH WIND WARNING HAS BEEN ISSUED FOR THE
LITTLE COLORADO RIVER VALLEY FROM WINSLOW TO SAINT JOHNS WHERE WIND
GUSTS MAY EXCEED 60 MPH.

IN ADDITION TO THE WINDS...RAIN AND SNOW WILL MOVE WEST TO EAST
ACROSS THE AREA TODAY...WITH SOME LINGERING SHOWERS CONTINUING
TONIGHT. THE HEAVIEST PRECIPITATION IS EXPECTED ALONG AND SOUTH AND
SOUTHWEST OF THE MOGOLLON RIM. ACCUMULATING SNOW IS LIKELY ACROSS
MUCH OF THE HIGH COUNTRY MONDAY AND MONDAY NIGHT...GENERALLY ABOVE
5500 FEET.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

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