Severe Thunderstorm Warning 39, NWS Flagstaff, AZ

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
305 PM MST THU AUG 14 2003

.SYNOPSIS...A WEAK LOW PRESSURE SYSTEM WILL GENERATE MORE
PRECIPITATION FROM LATE TONIGHT THROUGH MIDMORNING. AFTER ITS
PASSAGE...EXPECT CONTINUED SHOWERS AND THUNDERSTORMS EACH AFTERNOON
WITH SLIGHTLY COOLER TEMPERATURES FOR THE NEXT DAY OR TWO.

.DISCUSSION...DYNAMICS AHEAD OF THE INVERTED TROUGH APPROACHING
ARIZONA FROM THE EAST HAS PROMPTED ISSUANCE OF A SEVERE THUNDERSTORM
WATCH THROUGH 900 PM MST FOR AREAS OF SOUTH CENTRAL ARIZONA. SOME
ISOLATED SEVERE THUNDERSTORMS WILL OCCUR BEYOND THE BOUNDARIES OF
THE WATCH BOX. MOST ACTIVITY WILL OCCUR SOUTHEAST OF A LINE FROM
CANYON DE CHELLY NATIONAL MONUMENT TO PRESCOTT.

AS THE UPPER LEVEL TROUGH PROGRESSES WESTWARD...PRECIPITATION WILL
DEVELOP OVER NORTHEASTERN ARIZONA AROUND MIDNIGHT...MAKING ITS WAY
SOUTHWESTWARD INTO SOUTHERN YAVAPAI COUNTY TOMORROW MORNING. WHILE
MUCH OF THE RAINFALL WILL BE SHOWERY OR EVEN STRATIFORM...EXPECTED
ISOLATED THUNDERSTORMS TO OCCUR THROUGH THE NIGHT. COOL AIR NEAR THE
SURFACE TOMORROW WILL DELAY THE ONSET OF SIGNIFICANT CONVECTION
UNTIL LATER IN THE DAY...BUT PROBABILITIES FOR MORE ACTIVITY REMAIN
HIGH DUE TO DEEP MOISTURE AND COOL AIR ALOFT. EARLIEST CONVECTION
WILL BEGIN IN EASTERN ZONES AS THEY LOSE A BIT OF CLOUD COVER. WITH
SOILS IN YAVAPAI COUNTY ALREADY MOIST...WILL BE WATCHING RAINFALL
AMOUNTS CLOSELY FOR FLOODING POTENTIAL TOWARD MORNING. ON
SATURDAY...LOOK FOR POPS TO RECEDE TO MORE SEASONABLE LEVELS THOUGH
TEMPERATURES WILL REMAIN RATHER COOL THROUGH THE WEEKEND.

FOR THE EXTENDED...THE UPPER LEVEL LOW WILL MOVE NORTHWARD OUT OF
THE STATE LEAVING A RATHER NONDESCRIPT PRESSURE PATTERN OVER
ARIZONA. EXPECT CONTINUED...DAILY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS. HOWARD

.FGZ...SEVERE THUNDERSTORM WATCH FOR AZ ZONES 8/13/14/16/17/18/37
THROUGH 900 PM MST.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES LO/HI           PROBABILITY OF PRECIP
                 TON FRI   SAT     SUN        TON FRI   SAT     SUN
FLAGSTAFF        052/069 049/072 047/075      080 060 030 040 030 040
WINSLOW          063/081 060/083 058/087      060 050 020 020 020 020
PRESCOTT         062/079 060/079 059/082      070 060 030 030 020 020
PAGE             071/086 070/086 062/087      050 050 020 030 020 020
WINDOW ROCK      052/078 050/077 050/080      050 060 030 040 030 040
CANYON DE CHELLY 060/084 058/083 058/086      040 050 020 030 020 030
COTTONWOOD       070/093 068/094 067/098      060 050 020 020 020 020
GRAND CANYON     053/071 051/073 047/076      060 050 030 030 020 040
GREER            049/064 046/067 044/070      080 070 040 060 040 050
HEBER            054/074 051/077 049/080      080 070 040 050 030 040
JACOB LAKE       050/069 049/072 047/075      060 050 020 030 030 040
NAVAJO N.M.      064/080 063/081 062/084      060 050 020 030 030 040
PAYSON           062/083 060/083 059/086      060 060 030 030 020 020
SEDONA           067/087 065/087 064/090      060 060 020 030 020 020
SELIGMAN         062/082 060/082 058/086      040 040 020 020 020 030
SHOW LOW         059/074 056/076 054/080      060 060 030 040 030 030
ST. JOHNS        057/081 056/080 055/084      040 040 030 020 020 030
WUPATKI N.M.     064/083 061/085 059/089      060 050 020 020 020 020

AZZ004>018-037>040-150200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
925 AM MST THU AUG 14 2003

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

.DAY ONE...TODAY

CONVECTION WILL BEGIN TO FIRE FIRST OVER EASTERN PORTIONS OF
NORTHERN ARIZONA. CONVECTION OVER CENTRAL AND WESTERN PORTIONS WILL
BE DELAYED DUE TO CLOUD COVER INHIBITING SURFACE HEATING. EXPECT
SCATTERED COVERAGE. WITH SOILS ALREADY MOIST...WATCH FOR LOCALIZED
NUISANCE FLOODING IN SOME AREAS. EXPECT MORE WIDESPREAD
PRECIPITATION BETWEEN MIDNIGHT AND MIDMORNING ON FRIDAY AS DYNAMICS
ASSOCIATED WITH APPROACHING WEAK LOW PRESSURE CONTRIBUTE TO
INCREASED RAINFALL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

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.

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