Severe Thunderstorm Warning 92, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
245 PM MST THU OCT 4 2007

.SYNOPSIS...MOISTURE WILL LINGER ACROSS SOUTHEAST ARIZONA TONIGHT
AND FRIDAY RESULTING IN A SLIGHT CHANCE OF THUNDERSTORMS. A STRONG
STORM SYSTEM WILL MOVE THROUGH THE GREAT BASIN THIS WEEKEND PUSHING
THE MOISTURE OUT OF THE AREA AND ALSO BRINGING MUCH COOLER
TEMPERATURES. THE COLDEST LOW TEMPERATURES SINCE EARLY MAY IS
FORECAST FOR THE AREA ON SUNDAY MORNING. HIGH PRESSURE WILL REBUILD
OVER THE AREA NEXT WEEK RESULTING IN A WARMING TREND WITH DAYTIME
TEMPERATURES MUCH ABOVE NORMAL.

&&

.DISCUSSION...SATELLITE IMAGERY THIS AFTERNOON SHOWED GENERALLY
PARTLY CLOUDY SKIES ACROSS THE STATE WITH MOST OF THE THUNDERSTORM
ACTIVITY ACROSS NORTHERN ARIZONA. THERE HAVE BEEN A FEW SHOWERS AND
THUNDERSTORMS EAST AND NORTHEAST OF TUCSON THIS AFTERNOON. THE UPPER
LEVEL DISTURBANCE THAT WAS OFF THE NORTHERN BAJA COAST A THIS TIME
WEDNESDAY IS NOW MOVING INTO SOUTHWEST ARIZONA. THIS FEATURE IS
AIDING IN THE DEVELOPMENT OF STORMS ESPECIALLY NORTH AND EAST OF
TUCSON. PLENTY OF MOISTURE AROUND THE TUCSON MORNING SOUNDING
SHOWING PWAT VALUES AROUND 1.20 (190% ABOVE NORMAL) AND GOES
DERIVED PWAT LOOPS SHOWED ALL OF SOUTHERN ARIZONA HAS VALUES BETWEEN
1-1.5 THE UPPER LEVEL FEATURE WILL CONTINUE NORTHEAST ACROSS THE
STATE IN ADVANCE OF STRONG SYSTEM CURRENTLY MOVING THROUGH THE
PACIFIC NORTHWEST.

THIS STRONG PACIFIC SYSTEM WILL BRING A BIG CHANGE TO THE WEATHER
ACROSS THE AREA. FIRST THE PRESSURE GRADIENT WILL CONTINUE TO
TIGHTEN OVERNIGHT AND PEAK LATE FRIDAY RESULTING IN BREEZY TO WINDY
CONDITIONS FRIDAY AFTERNOON/EVENING. THE HIGHEST WIND SPEEDS/GUSTS
WILL BE UP IN THE WHITE MOUNTAINS WHERE THE 700 MB WIND IS PROGGED
TO BE NEAR 50 KTS FRIDAY AFTERNOON AND EVENING. WITH THAT IN MIND I
WILL HOIST A WIND ADVISORY FRIDAY FOR PUBLIC ZONE 19 BETWEEN 1 PM
AND 11 PM. ENOUGH LOW LEVEL MOISTURE WILL BE AROUND THAT THERE IS
LITTLE FIRE WEATHER CONCERNS ON FRIDAY.

MODELS AT ODDS ON HOW TO HANDLE MOISTURE THAT IS CURRENTLY IN PLACE
AND HOW THE APPROACHING COLD FRONT LATE FRIDAY INTO SATURDAY WILL
INTERACT WITH THIS MOISTURE. BELIEVE THAT THE NAM HAS THE BETTER
HANDLE OF THE SITUATION BY SHOWING A THIN BAND OF CLOUDS/EMBEDDED
VERY LIGHT SHOWERS DEVELOPING ALONG THE FRONT FRIDAY AFTERNOON AND
THEN MOVING SLOWLY EAST ACROSS THE AREA INTO SATURDAY. THUS I HAVE
INTRODUCED A SLIGHT CHANCE OF SHOWERS STARTING LATE IN THE DAY IN
WESTERN PIMA COUNTY AND THEN MOVED THIS SLIGHT CHANCE INTO EASTERN
PIMA COUNTY LATE FRIDAY NIGHT AND THEN ACROSS AREAS EAST OF TUCSON
ON SATURDAY. CONFIDENCE ON THE LOW SIDE...THUS THE POPS ARE VERY
LOW...LESS THAN 15%.

THE WEEKEND LOOKS DOWN RIGHT GORGEOUS WITH THE AREA ON THE BACK SIDE
OF WEATHER SYSTEM THUS BRINGING A DRY AND COOLER WEST NORTHWEST FLOW
ALOFT. THIS WILL RESULT IN DAYTIME TEMPERATURES THIS WEEKEND BEING 8
TO 12 DEGREES COOLER THAN THE PAST SEVERAL DAYS. SUNDAY MORNING WILL
LIKELY SEE THE COOLEST LOW TEMPERATURES SINCE EARLY MAY.

ENJOY THE TEMPERATURES THIS WEEKEND...SINCE IT WILL BE SHORT-LIVED
AS THE HEAT ENGINE WILL ONCE AGAIN START UP AS STRONG HIGH PRESSURE
FOR OCTOBER BUILDS OVER THE STATE. THIS MEANS BY NEXT WEDNESDAY AND
THURSDAY...HIGH TEMPERATURES IN THE LOW DESERTS WILL BE IN THE 95 TO
102 RANGE...WHICH IS HOTTER THAN WHAT HAS OCCURED OVER THE PAST
SEVERAL DAYS. WHEN WILL SUMMER END

&&

.AVIATION...PARTLY CLOUDY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS
THIS EVENING. A STRONG TROUGH WILL DEEPEN ALONG THE WEST COAST
TOMORROW FOR SUSTAINED SOUTHWEST TO WEST WINDS OF 20 KTS AND HIGHER
ON FRIDAY AND SATURDAY. THESE STRONG WIND SPEEDS ALSO RAISE THE
CONCERN OF LOCALLY BLOWING DUST WITH VISIBILITIES DOWN TO 1 MILE
ESPECIALLY ON FRIDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
 WIND ADVISORY FRIDAY FOR PUBLIC ZONE 19 FROM 1 PM TO 11 PM.

WEATHER.GOV/TUCSON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
325 PM MST THU OCT 4 2007

AZZ019-051415-
NORTHERN GREENLEE COUNTY-
325 PM MST THU OCT 4 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
ARIZONA.

.DAY ONE...TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A WIND ADVISORY HAS BEEN POSTED FOR FRIDAY BETWEEN 2 PM TO 11 PM.
A STRONG WEATHER SYSTEM MOVING TOWARD THE GREAT BASIN FRIDAY WILL
INCREASE WIND SPEEDS FRIDAY AFTERNOON AND EVENING IN THE 15 TO 30
MPH RANGE WITH GUSTS UP TO 45 MPH. THE WIND SPEEDS WILL DECREASE
ON SATURDAY. AS THIS SYSTEM MOVES THROUGH THE GREAT BASIN ON
SATURDAY...THE COLDEST TEMPERATURES SINCE EARLY MAY WILL OCCUR
SUNDAY MORNING. LOW TEMPERATURES ARE WILL GENERALLY BE IN THE
UPPER 20S AT THE HIGHEST ELEVATIONS TO THE UPPER 30S AND LOW 40S
ELSEWHERE.

.SPOTTER INFORMATION STATEMENT...

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