Flood in Arizona, July 24, 2002

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 PM MST WED JUL 24 2002

.SYNOPSIS...THE DAILY SHOWERS AND THUNDERSTORMS WILL CONTINUE
THROUGH THE END OF THE WEEK. A DOWN TREND IN THE SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED OVER THE WEEKEND AS WESTERLY
FLOW ALOFT BRINGS DRIER AIR INTO NORTHERN ARIZONA. TEMPERATURES
WILL REMAIN SEASONAL.

.DISCUSSION...DEEP LAYER MID-LEVEL ANTICYCLONIC CIRCULATION WAS
LOCATED OVER THE FOUR-CORNERS REGION THIS AFTERNOON. ANTICYCLONE
WILL SHIFT EASTWARD OVERNIGHT AS A MID-LEVEL TROUGH MOVES OVER THE
GREAT BASIN. THE TROUGH WILL REMAIN ESSENTIALLY STATIONARY OVER THE
GREAT BASIN FROM THURSDAY INTO SATURDAY WITH DEEP BUT WEAK SOUTHWEST
FLOW DEVELOPING. FOR TONIGHT...THINK WITH DEVELOPING TROUGH AND DEEP
MOISTURE STORMS WILL BE POSSIBLE ALL NIGHT. THEY WILL BE MOST
NUMEROUS DURING THE EVENING HOURS. ON THURSDAY...FLOW SHIFTS TO
SOUTHWEST THROUGH A DEEP LAYER. WITH DEEP MOISTURE OVER WESTERN
ARIZONA THINK THIS WILL ADVECT ACROSS THE AREA ON THURSDAY.
SOUTHWEST TO WEST FLOW WILL FAVOR THE MOST NUMEROUS SHOWERS FROM THE
MOGOLLON RIM NORTHWARD. ACTIVITY WILL LIKELY INCREASE OVER THE
NORTHEAST PORTION OF THE STATE ON THURSDAY. ON FRIDAY...THINK
MOISTURE WILL STILL BE SLOW TO MOVE BUT WILL GO WITH ONLY A SLIGHT
CHANCE OVER THE FAR WESTERN COUNTY WARNING AREA (CWA) AS A COOLER
AIR MASS MOVES IN FROM THE PACIFIC AND STABILIZES THINGS. THINK
THERE WILL STILL BE A FAIR AMOUNT OF THUNDERSTORMS ALONG THE
MOGOLLON RIM...WHITE MOUNTAINS NORTHWARD. BY SATURDAY DRYING
CONTINUES WITH ONLY ISOLATED TO SCATTERED STORMS WITH PACIFIC AIR
MASS MOVING OVER MORE OF THE CWA.

IN THE EXTENDED...THE FLOW GETS VERY COMPLICATED. ARIZONA WILL BE
UNDER A WEAK TROUGH/FLOW BETWEEN THE EASTERN PACIFIC SUBTROPICAL
RIDGE TO THE NORTHWEST AND THE ATLANTIC SUBTROPICAL RIDGE TO THE
SOUTHEAST. LOOKS LIKE THE TREND WILL BE TOWARD SOME DRYING AS FLOW
TRENDS FROM THE WEST. WESTERLY FLOW USUALLY BRINGS IN DRIER AIR AT
ALL LEVELS WITH SOME COOLING IN THE LOWEST LEVELS WHICH PUTS A
DAMPER ON THUNDERSTORM ACTIVITY. HOWEVER...WITH THE UNCERTAINTIES
ASSOCIATED WITH THE COMPLEX INTERACTION OF SYSTEMS NOT CERTAIN IT
WILL COMPLETELY STABILIZE. AS A RESULT...WILL CONTINUE WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.

MCCOLLUM

.FGZ...NONE

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES LO/HI           PROBABILITY OF PRECIP
                 TON THU   FRI     SAT        TON THU   FRI     SAT
FLAGSTAFF        053/077 054/078 052/080      030 070 030 040 020 030
WINSLOW          063/088 065/088 063/090      030 060 030 040 020 030
PRESCOTT         062/086 063/087 061/089      030 050 020 020 020 020
PAGE             072/092 072/094 070/096      020 060 030 020 020 020
WINDOW ROCK      054/080 055/079 052/081      020 070 050 050 040 040
CANYON DE CHELLY 060/086 061/085 058/087      020 060 040 040 030 030
COTTONWOOD       070/097 071/098 069/100      020 040 020 020 020 020
GRAND CANYON     052/079 053/080 051/082      020 060 020 030 020 020
GREER            049/073 050/074 048/076      040 080 050 060 040 050
HEBER            054/082 055/083 053/085      040 060 050 050 030 040
JACOB LAKE       053/075 054/076 052/078      020 060 020 030 020 020
NAVAJO N.M.      058/080 059/079 056/081      020 060 040 040 030 030
PAYSON           063/091 064/092 062/094      030 020 020 020 020 020
SEDONA           068/095 069/096 067/098      020 040 020 020 020 020
SELIGMAN         055/089 056/090 054/092      020 040 010 010 010 010
SHOW LOW         061/083 062/084 060/086      030 060 040 040 030 030
ST. JOHNS        058/082 060/082 058/084      040 070 040 050 030 040
WUPATKI N.M.     066/090 068/090 066/092      030 060 030 050 020 030