Severe Thunderstorm Warning 54, NWS Flagstaff, AZ

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
940 AM MST FRI AUG 22 2003

.SYNOPSIS...HIGH PRESSURE CENTERED NORTHEAST OF ARIZONA WILL
CONTINUE TO CIRCULATE MOISTURE OVER THE NORTHLAND. EXPECT AFTERNOON
AND EVENING SHOWERS TO CONTINUE EACH DAY THROUGH THE WEEKEND.

.DISCUSSION...WEAK BAROCLINICITY BETWEEN THE A TROUGH OVER THE WEST
COAST AND THE SOUTHWESTERN RIDGE...ALONG WITH LOW-LEVEL CONVERGENCE
AND 250-300MB DIV...ALL COMBINING TO PRODUCE THIS MORNINGS
PERSISTENT CONVECTION ALONG THE COLORADO RIVER. UPPER LEVEL DIV AND
LOW LEVEL CONV SIGNATURE WILL SHIFT EAST TODAY AS THE TROUGH LIFTS
OUT THROUGH THE NORTHERN GREAT BASIN. THIS WILL BRING DEEP MOISTURE
PLUME JUST TO OUR SOUTH SQUARELY OVER THE CENTRAL PORTIONS OF THE
STATE DURING THE AFTERNOON HOURS. JUST ENOUGH SHEAR EXISTS FOR
STRONG TO SEVERE STORM DEVELOPMENT TODAY...WITH GENERALLY SOUTHERLY
STORM MOTION. WILL LIKELY ISSUE A FLASH FLOOD WATCH...WE WILL
COORDINATE LATER THIS MORNING. REGION AFFECTED BY AN EASTERLY WAVE
OVER THE WEEKEND WITH A VERY FAVORABLE STORM ENVIRONMENT IN PLACE AT
LEAST THROUGH SUNDAY. PETERSON.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES HI/LO           PROBABILITY OF PRECIP
                 TDY TON   SAT     SUN        TDY TON   SAT   SUN
FLAGSTAFF        076/054 074/053 076/050      050 040 050 020 040 020
WINSLOW          092/066 090/065 089/062      040 030 040 020 030 020
PRESCOTT         085/061 083/060 086/057      040 030 050 020 040 020
PAGE             093/072 091/071 091/068      030 020 030 020 020 020
WINDOW ROCK      085/054 083/053 082/050      040 030 050 020 040 020
CANYON DE CHELLY 094/065 092/064 088/061      040 030 040 020 030 020
COTTONWOOD       096/070 094/069 097/066      040 030 040 020 030 020
GRAND CANYON     082/053 080/052 081/049      040 030 040 020 030 020
GREER            073/049 071/048 071/045      060 050 060 030 060 030
HEBER            083/054 081/053 081/050      050 040 050 020 040 020
JACOB LAKE       076/052 074/051 074/048      040 030 040 020 040 020
NAVAJO N.M.      085/059 083/058 082/055      040 030 040 020 030 020
PAYSON           091/061 089/060 090/057      040 030 040 030 040 030
SEDONA           095/069 093/068 094/065      040 030 050 020 030 020
SELIGMAN         089/059 087/058 089/055      030 030 040 020 020 020
SHOW LOW         085/057 083/056 081/053      050 040 050 020 040 020
ST. JOHNS        093/065 091/064 089/061      040 030 050 020 040 020
WUPATKI N.M.     093/065 091/064 091/061      040 030 040 020 030 020

AZZ004>018-037>040-230200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1010 AM MST FRI AUG 22 2003

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

.DAY ONE...TODAY

...FLASH FLOOD WATCH FOR ALL OF COCONINO AND YAVAPAI COUNTIES FROM
NOON MST UNTIL 11 PM MST TODAY...

STRONG STORMS CONTAINING HEAVY RAIN ARE EXPECTED TO DEVELOP TODAY
ALONG A PLUME OF DEEP MOISTURE EXTENDING NORTHWARD THROUGH MOST OF
YAVAPAI AND COCONINO COUNTIES. STORMS WILL DEVELOP OVER THE WATCH
AREA BY 11 AM MST...WITH THE STRONGEST STORMS IN THE AFTERNOON
HOURS. SOME STORMS MAY BECOME SEVERE THIS AFTERNOON WITH HAIL SIZES
OF AROUND AN INCH WITH THE STRONGEST STORMS.

SOIL CONDITIONS OVER YAVAPAI AND COCONINO COUNTIES ARE
SATURATED...AND ANY ADDITIONAL HEAVY RAIN MAY LEAD TO FLOODING.

STORMS THAT DEVELOP MAINLY EAST OF FLAGSTAFF WILL BE MORE BENIGN AND
LESS WIDESPREAD. ONLY ISOLATED STRONGER STORMS ARE EXPECTED IN THESE
AREAS...WITH MUCH LESS OF A CHANCE FOR FLOODING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A MOIST AND UNSTABLE AIR MASS WILL REMAIN OVER ARIZONA RESULTING IN
A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. FLOODING POTENTIAL
OVER THE WEEKEND WILL REMAIN MODERATE OVER YAVAPAI AND COCONINO
COUNTIES.

.SPOTTER INFORMATION STATEMENT...

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

DEFINITION OF HAZARDOUS WEATHER...A WEATHER EVENT POSING A THREAT
TO LIFE AND PROPERTY.