Flash Flood in Arizona, September 9, 2003

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
845 PM MST MON SEP 8 2003

.SYNOPSIS...MOISTURE WILL BE ON THE INCREASE TONIGHT AS A STRONG LOW
PRESSURE SYSTEM OVER THE GREAT BASIN DRAWS TROPICAL MOISTURE
NORTHWARD. AS A RESULT...THE CHANCE OF SHOWERS AND THUNDERSTORMS
WILL INCREASE OVERNIGHT. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS
TOMORROW AND WEDNESDAY. DRY AND WARM WEATHER WILL RETURN TO NORTHERN
ARIZONA ON THURSDAY AND CONTINUE INTO THE WEEKEND.

.DISCUSSION...BAND OF MID/HIGH CLOUDS WAS MOVING OUT OF THE CWFA
THIS EVENING BUT ANOTHER BATCH OF LOW/MID CLOUDS WAS MOVING INTO THE
NW CORNER. WILL MAINTAIN PC CONDITIONS OVERNIGHT. NO UPDATES
REQUIRED FOR ZFP.

BROAD MODERATE AMPLITUDE TROUGH CONTINUES TO DEVELOP OVER THE WEST
AND GREAT BASIN THIS EVENING. EVEN THOUGH SOME DRIER AIR HAS BEGUN
TO FILTER ACROSS THE NRN PORTION OF AZ IN RESPONSE TO THE PASSAGE OF
THE FIRST S/W TROUGH...LOWERING PRESSURE AND BACKING WINDS WILL DRAW
MOISTURE ACROSS THE STATE OVERNIGHT AND TOMORROW. DIVQ FIELDS
INDICATE MODERATE UPWARD FORCING OVERNIGHT AND TOMORROW. WIND FIELDS
WILL INCREASE FROM THE SW OVERNIGHT AND TOMORROW PRODUCING A
MODERATE OROGRAPHIC COMPONENT. LAPSE RATES WILL BE FAIRLY STABLE SO
THAT DEEP CONVECTION MAY BE INHIBITED. NONETHELESS...COMBINATION OF
INCREASING MOISTURE...OROGRAPHIC FLOW...AND DYNAMIC LIFT SHOULD
PRODUCE BROAD AREAS OF LIGHT TO MODERATE RAINFALL STARTING LATE
TONIGHT AND CONTINUING THROUGH THE DAY ON WED. BELIEVE THAT STRONG
OROGRAPHIC COMPONENT AND LAPSE RATE STABILITY WILL RESULT IN A RAIN
SHADOW DEVELOPING IN THE LITTLE COLORADO RIVER (LCR) VALLEY...SO
HAVE REDUCED POPS THERE ACCORDINGLY. MODELS CONSISTENT IN MOVING THE
TROUGH TO THE EAST ON WED AND BRINGING A DRIER NW FLOW ACROSS AZ ON
THU. WILL CARRY SOME DIMINISHING CHANCES OF PCPN ON WED...AND THEN
DRY IT OUT ACROSS NRN AZ FROM THU ONWARD. MONSOON SEASON IS OVER.  DB

.NOTE...EFFECTIVE WEDNESDAY OCTOBER 1 2003...THE TEMPERATURES AND
PROBABILITIES OF PRECIPITATION TABLE (BELOW) WILL NO LONGER BE
APPENDED TO THIS PRODUCT. THE INFORMATION...ALONG WITH PREVAILING
DAYTIME WEATHER...WILL BE AVAILABLE IN THE RECENTLY ADOPTED TABULAR
STATE FORECAST (SFT). THE SFT PROVIDES THESE FORECASTS THROUGH 7
DAYS. THE WMO HEADER FOR THIS PRODUCT IS FPUS65 KPSR. THE PRODUCT
IDENTIFIER IS PHXSFTAZ. USING THE INTERNET...YOU CAN ACCESS THE SFT
DIRECTLY AT HTTP://WWW.WRH.NOAA.GOV/CGI-BIN/GPRODUCT.PL?FLGPHXSFTAZ

.FGZ...NONE.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES LO/HI           PROBABILITY OF PRECIP
                 TON TUE   WED     THU        TON TUE   WED     THU
FLAGSTAFF        053/064 050/067 043/070      030 070 050 040 000 000
WINSLOW          066/080 064/080 057/083      020 060 040 030 020 000
PRESCOTT         060/072 058/075 051/078      030 060 050 030 000 000
PAGE             071/082 068/083 061/086      020 050 040 030 000 000
WINDOW ROCK      050/068 049/069 042/072      020 060 050 050 040 000
CANYON DE CHELLY 057/074 056/075 049/078      020 060 050 040 030 000
COTTONWOOD       068/083 066/086 059/089      030 060 050 030 000 000
GRAND CANYON     054/065 051/068 044/071      020 050 050 040 000 000
GREER            052/061 049/064 042/067      030 060 050 050 040 000
HEBER            056/069 053/072 046/075      030 070 050 040 030 000
JACOB LAKE       053/061 050/064 043/067      030 050 050 030 000 000
NAVAJO N.M.      056/066 055/067 048/070      020 060 050 040 000 000
PAYSON           060/076 058/079 051/082      030 070 050 040 020 000
SEDONA           067/080 065/083 058/086      030 070 050 040 000 000
SELIGMAN         058/074 056/077 049/080      020 050 050 030 000 000
SHOW LOW         062/070 059/073 052/076      030 060 050 040 030 000
ST. JOHNS        062/076 060/076 053/079      020 060 050 040 030 000
WUPATKI N.M.     068/082 066/082 059/085      020 060 050 030 000 000

AZZ004>018-037>040-090200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1000 AM MST MON SEP 8 2003

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

.DAY ONE...TODAY

A MOIST BUT STABLE AIR MASS WILL MOVE ACROSS ARIZONA TODAY WITH ONLY
ISOLATED SHOWERS AND THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A STRONG LOW PRESSURE SYSTEM OVER UTAH WILL COMBINE WITH DEEP
MOISTURE ON TUESDAY AND TUESDAY NIGHT TO PRODUCE WIDESPREAD SHOWERS
AND THUNDERSTORMS. THE DEEPEST MOISTURE AND MOST UNSTABLE AIR
MASS WILL BE LOCATED ALONG AND SOUTH OF THE MOGOLLON RIM...INCLUDING
MUCH OF YAVAPAI AND GILA COUNTIES.

SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE TUESDAY MORNING
WITH THE HEAVIEST RAINFALL EXPECTED TO HIT TUESDAY AFTERNOON AND
NIGHT. BY WEDNESDAY MORNING...MANY LOCATIONS ALONG AND SOUTH OF THE
MOGOLLON RIM ARE EXPECTED TO RECEIVE UP TO 1 INCH OF RAIN...WITH
LOCAL ACCUMULATIONS OF UP TO 2 INCHES.

PLEASE STAY TUNED FOR FURTHER UPDATES ON THIS DEVELOPING WEATHER
SYSTEM.