Severe Thunderstorm Warning 93, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
330 PM MST FRI OCT 10 2008

.SYNOPSIS...A STRONG STORM SYSTEM DEVELOPING OVER THE WESTERN GREAT
BASIN WILL BRING CONTINUED VERY WINDY CONDITIONS TO MUCH OF THE
REGION THROUGH SATURDAY. THE WINDIEST PERIOD WILL BE LATE THIS
EVENING INTO SATURDAY AFTERNOON...WHEN HIGH WINDS IN EXCESS OF 60
MILES PER HOUR ARE POSSIBLE...MAINLY FROM THE MOGOLLON RIM
NORTHEASTWARD. THIS STORM WILL ALSO BRING SHARPLY COLDER
TEMPERATURES...WITH AREAS OF RAIN EAST OF FLAGSTAFF LATE TONIGHT AND
SATURDAY...AND A CHANCE OF RAIN OR SNOW SHOWERS NORTHWEST OF
FLAGSTAFF. COLD TEMPERATURES WILL REMAIN SUNDAY AND MONDAY...BEFORE
GRADUAL IMPROVEMENT FOR THE REMAINDER OF NEXT WEEK.

&&

.DISCUSSION...VERY STRONG AND COLD LOW PRESSURE SYSTEM FOR THIS
EARLY IN THE SEASON IS CENTERED OVER NEVADA AND CENTRAL CALIFORNIA
THIS AFTERNOON. A SURFACE LOW IS DEEPENING OVER SOUTHERN UTAH AND
THIS IS CREATING WINDY CONDITIONS OVER NORTHERN ARIZONA. SUSTAINED
SPEEDS OF 20 TO 30 MPH WITH GUSTS OF 40 TO 50 MPH WILL CONTINUE
THROUGH THE EVENING...AND A WIND ADVISORY REMAINS IN EFFECT. THE
MAIN CONCERN WILL SHIFT TO THE POTENTIAL FOR VERY STRONG WINDS FROM
LATE TONIGHT THROUGH SATURDAY...MAINLY FROM THE MOGOLLON RIM
NORTHEASTWARD. AS THE STORM SYSTEM AND COLD FRONT CONTINUE TO
APPROACH...700 MB WINDS ARE FORECAST TO INCREASE TO 60-75
KTS...ALONG WITH A VERY STRONG COLD FRONT. A HIGH WIND WARNING WILL
BE ISSUED ALONG AND NORTHEAST OF THE MOGOLLON RIM FROM 1 AM UNTIL 6
PM SATURDAY. AREAS JUST NORTHEAST OF HIGHER TERRAIN WILL SEE THE
STRONGEST WINDS AT FIRST...INCLUDING DONEY PARK AND AREAS JUST NORTH
OF THE MOGOLLON RIM AND WHITE MTNS. AFTER SUNRISE...WINDS WILL
INCREASE OVER A LARGE AREA WITH SUSTAINED SPEEDS OF 30-40 MPH AND
GUSTS AS HIGH AS 60-70 MPH. SEE THE HIGH WIND WARNING...PHXNPWFGZ
FOR DETAILS.

THE OTHER ASPECT OF THIS STORM WILL BE MUCH COLDER TEMPERATURES AND
PRECIPITATION CHANCES. MOISTURE BEING PULLED NORTHWARD IN ADVANCE OF
THIS LOW SHOULD ARRIVE IN EAST CENTRAL AZ OVERNIGHT AND INTO
SATURDAY. STRONG UPSLOPE FLOW WILL BRING HIGH RAIN CHANCES FOR THE
WHITE MTNS WITH LESSER CHANCES FROM THE PAYSON AREA TOWARD WINDOW
ROCK. THE WESTWARD EXTENT OF THE MOISTURE IS STILL UNCERTAIN...SO A
20-30 PCT CHANCE OF SHOWERS IS IN THE FORECAST FOR MOST OTHER AREAS.
HIGH TEMPERATURES SATURDAY WILL BE REACHED EARLY IN THE DAY FOR MANY
AREAS...WITH TEMPERATURES FALLING INTO THE UPPER 30S OR 40S BY
AFTERNOON OVER THE HIGHER TERRAIN.

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 00Z PACKAGE...A STRONG LOW PRESSURE SYSTEM WILL
BRING STRONG WINDS THROUGH SATURDAY. EXPECT SOUTHWEST WINDS OF 25 TO
35 KTS WITH GUSTS REACHING 45 KTS THIS EVENING AND AGAIN SATURDAY
AFTERNOON. SOME AREAS WILL HAVE STRONG WINDS OVERNIGHT TONIGHT AS
WELL. SOME MOISTURE WILL MOVE NORTHWARD OVER FAR EASTERN ARIZONA
WITH AN INCREASING CHANCE OF SHOWERS WITH CEILINGS OF 1-3 KFT AGL BY
SATURDAY MORNING. ELSEWHERE VFR CONDITIONS ARE ANTICIPATED. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

WIND ADVISORY UNTIL 1 AM MST SATURDAY AZZ009>018-039-040.

HIGH WIND WARNING 1 AM MST SATURDAY THROUGH 6 PM MST SATURDAY FOR
AZZ009>018-039-040

WIND ADVISORY UNTIL 4 PM MST SATURDAY FOR AZZ004>008-037-038.

&&

PUBLIC.........JJ
AVIATION.......MAS

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