000
FXUS65 KFGZ 111559
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
850 AM MST SAT OCT 11 2008
.SYNOPSIS...A STRONG COLD FRONT WILL MOVE THROUGH NORTHERN ARIZONA
TODAY. VERY WINDY CONDITIONS ARE EXPECTED THROUGH SUNSET. WIND GUSTS
UP TO 70 MILES PER HOUR ARE FORECAST FOR THE MOGOLLON RIM...NAVAJO
AND APACHE COUNTIES. THIS STORM SYSTEM WILL BRING SHARPLY COLDER
TEMPERATURES...WITH AREAS OF RAIN AND THUNDERSTORMS EAST OF
FLAGSTAFF TODAY...AND A CHANCE OF RAIN OR SNOW SHOWERS NORTHWEST OF
FLAGSTAFF. COLD TEMPERATURES WILL REMAIN SUNDAY AND MONDAY. A
GRADUAL IMPROVEMENT IN THE WEATHER IS EXPECTED STARTING TUESDAY.
&&
.DISCUSSION...AT 8 AM MST...THE SURFACE COLD FRONT APPEARS TO BE
ALONG A LINE FROM PAGE TO FLAGSTAFF TO BLACK CANYON CITY. AREAS EAST
OF THIS LINE WILL SEE WIND GUSTS FROM 55 TO 70 MPH TODAY. THE
SUSTAINED WIND FORECASTS TODAY OF 35 TO 45 MPH FOR APACHE AND NAVAJO
COUNTIES LOOKS GOOD. THE WINSLOW AIRPORT REPORTED A GUST TO 61 MPH
AT 820 THIS MORNING. WINDS FROM THIS MORNINGS SOUNDING ARE 39 KNOTS
AT 9000 FT MSL AND 70 KNOT AT 14000 FT MSL.
SEVERE THUNDERSTORMS ARE POSSIBLE THROUGH MID AFTERNOON FOR AREAS
EAST OF A LINE FROM PAYSON TO WINDOW ROCK. THERE ARE THUNDERSTORMS
OCCURRING IN THIS AREA NOW...WITH STORM MOTIONS TO THE NORTHEAST
FROM 45 TO 55 MPH. DAMAGING WIND AND HAIL ARE THE MAIN THREATS.
CURRENT GRIDS AND PRODUCTS ARE IN GOOD SHAPE.
PREV DISCUSSION 350 AM...INFRARED SATELLITE LOOP IS SHOWING
INCREASING CLOUD COVER AND COOLING TOPS ACROSS NORTHERN ARIZONA THIS
MORNING...ESPECIALLY OVER NORTHERN GILA COUNTY AND THE WHITE
MOUNTAINS. SURFACE DEWPOINTS ACROSS THE ENTIRE FORECAST AREA HAVE
GONE UP OVER THE PAST SIX HOURS OR SO. HOWEVER...OUT TO THE WEST DRY
AIR IS BEGINNING TO PUSH EASTWARD AS SURFACE DEWPOINTS ARE STARTING
TO COME DOWN ACROSS NEEDLES AND BLYTHE. WINDS HAVE STAYED UP ALL
NIGHT AND HAVE HOVERED NEAR WIND ADVISORY CRITERIA ACROSS THE HIGH
TERRAIN.
WATER VAPOR IMAGERY SHOWING LARGE UPPER LOW OVER EAST CENTRAL
CALIFORNIA AND WESTERN NEVADA AT THIS TIME. TO THE SOUTH OFF THE TIP
OF BAJA IS HURRICANE NORBERT. SOME MOISTURE FROM THIS TROPICAL
SYSTEM IS BEING PULLED NORTHEASTWARD AND ACROSS SOUTHEASTERN
ARIZONA. ALREADY SHOWERS AND THUNDERSTORMS HAVE FORMED OVER TUCSON`S
CWA AND CURRENT RADAR SHOWS CONVECTIVE ACTIVITY STARTING ACROSS
NORTHERN GILA COUNTY AND THE WHITES WITH A FEW LIGHTNING STRIKES
NOTED NEAR MOUNT BALDY PEAK.
THIS STRONG AREA OF LOW PRESSURE IS FORECAST TO MOVE NORTHEAST
ACROSS THE GREAT BASIN TODAY. STRONG SOUTHWEST WINDS BEING GENERATED
BY THIS SYSTEM WILL RESULT IN VERY WINDY CONDITIONS ACROSS NORTHERN
ARIZONA THIS MORNING AND AFTERNOON. 700 MB WINDS ARE FORECAST TO BE
IN THE 50 TO 75 KNOT RANGE DURING THIS TIME PERIOD...WITH THE
STRONGEST WINDS BEING FELT FROM THE MOGOLLON RIM ALONG TO THE WHITES
AND NORTH TO THE UTAH BORDER. A HIGH WIND WARNING HAS ALREADY BEEN
ISSUED BY EARLIER SHIFTS AND THIS WILL BE CONTINUED. FOR AREAS
WEST...A WIND ADVISORY WAS ALSO ISSUED. FOR A MORE DETAILED
DESCRIPTION ON THESE WIND PRODUCTS...PLEASE SEE PHXNPWFGZ.
ONE OF THE MAIN ISSUES FOR TODAY WILL BE THE STRENGTH OF THE
CONVECTIVE GUSTS. BECAUSE OF THE VERY STRONG WINDS ALOFT...ANY
SHOWER OR THUNDERSTORM COULD BRING DOWN THESE STRONG WINDS. THE HIGH
WIND WARNING WILL HANDLE THIS OVER THE WHITE MOUNTAINS...AND WE
PROBABLY GO BACK AND ADD DAMAGING WIND WORDING TO NORTHERN GILA
COUNTY.
THE BEST CHANCES FOR PRECIPITATION WILL BE ACROSS THE HIGH TERRAIN
IN THE SOUTHEAST PART OF THE FORECAST AREA WHERE THE MOISTURE WILL
BE MOST CONCENTRATED. A SECONDARY AREA OF CHANCE POPS ARE OVER THE
KAIBAB PLATEAU FOR TODAY AS COLD AIR ALOFT ASSOCIATED WITH
THE UPPER TROUGH SWINGS THROUGH THAT AREA.
THE SYSTEM IS ANTICIPATED TO MOVE ACROSS NORTHERN UTAH THIS EVENING
WITH ITS EFFECTS OVER THE NORTHLAND WANING. WINDS WILL GRADUALLY
DIMINISH AND SKIES WILL EVENTUALLY CLEAR AS DRY AIR FROM THE WEST
FILTERS IN. AS A RESULT...A HARD FREEZE IS LIKELY FOR MOST AREAS
ABOVE 4500-5000 FEET SATURDAY NIGHT AND SUNDAY NIGHT...THE FIRST OF
THE SEASON AT SOME LOCATIONS. EXPECT WARMER TEMPERATURES FOR MONDAY
THROUGH MOST OF NEXT WEEK AS THE STORM SYSTEM MOVES AWAY FROM THE
STATE. THERE IS A POSSIBILITY OF SOME MOISTURE MOVING IN FROM THE
SOUTHEAST BY MIDWEEK...AND A LOW CHANCE OF SHOWERS HAS BEEN INCLUDED
IN THE FORECAST.
&&
.AVIATION...FOR THE 12Z PACKAGE...A STRONG LOW PRESSURE SYSTEM WILL
BRING VERY STRONG WINDS TO NORTHERN ARIZONA TODAY. EXPECT SOUTHWEST
WINDS OF 15 TO 30 KTS EARLY...INCREASING THROUGH THE DAY. THE
STRONGEST WINDS WILL OCCUR ALONG AND NORTH OF THE MOGOLLON
RIM...WHERE AFTERNOON GUSTS WILL REACH 50 KTS IN MANY PLACES AND
POSSIBLY AS HIGH AS 60 KTS EAST OF FLAGSTAFF. WINDS WILL WEAKEN
AFTER SUNSET. IN ADDITION...CLOUDS AND SHOWERS WILL BRING PERIODS OF
MVFR CONDITIONS TO PORTIONS OF EAST CENTRAL ARIZONA TODAY AND
TONIGHT. ELSEWHERE ACROSS NORTHERN ARIZONA...VFR CONDITIONS ARE
ANTICIPATED. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 2 PM MST THIS AFTERNOON
FOR AZZ016-018.
HIGH WIND WARNING IN EFFECT UNTIL 6 PM MST THIS EVENING FOR
AZZ009>018-039-040
WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR AZZ004>008-037-038.
&&
$$
PUBLIC.........42
AVIATION.......MCCOLLUM
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.
