Severe Thunderstorm Warning 56, NWS Flagstaff, AZ

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
930 AM MST FRI AUG 10 2001

.SYNOPSIS...A MOIST NORTHEASTERLY FLOW WILL CONTINUE TO PRODUCE
SHOWERS AND THUNDERSTORMS OVER NORTHERN ARIZONA TODAY. LOW PRESSURE
TO THE EAST WILL BEGIN TO WEAKEN TODAY WITH HIGH PRESSURE BUILDING
OVER SOUTHERN CALIFORNIA. THIS WILL ALLOW A SOMEWHAT DRIER AND
WARMER NORTHWEST FLOW TO DEVELOP ON SATURDAY. HIGH PRESSURE WILL
GRADUALLY SHIFT TO THE FOUR CORNERS AREA BY EARLY NEXT WEEK WITH
ENOUGH MOISTURE FOR A CONTINUING CHANCE OF SHOWERS AND
THUNDERSTORMS.

.DISCUSSION...UPPER TROUGH OVER NEW MEXICO RAPIDLY WEAKENING THIS
MORNING WITH THE UPPER RIDGE OVER SOUTHERN CALIFORNIA BEGINNING TO
DOMINATE THE FLOW PATTERN. IN ANY CASE A GENERAL NORTHERLY FLOW
SHOULD REMAIN THROUGH SATURDAY WITH GRADUAL DRYING OVER THE WESTERN
PORTIONS OF THE COUNTY WARNING AREA (CWA). IF ANYTHING...MOISTURE
WILL INCREASE OVER THE EASTERN PORTIONS OF THE CWA AS THE DEEP
MOISTURE AXIS MOVES EASTWARD. FOR TODAY...THERE ARE STILL WIDESPREAD
1.0 TO 1.5 PRECIPITABLE WATER VALUES AND THE AIR MASS REMAINS VERY
UNSTABLE. THIS MEANS LOTS OF HEAVY RAIN PRODUCING THUNDERSTORMS.
PORTIONS OF YAVAPAI AND COCONINO COUNTIES HAVE SEEN LOTS OF RAIN
OVER THE PAST 48-HOURS AND SOIL CONDITIONS ARE VERY MOIST. WITH DEEP
MOISTURE REMAINING A FLASH FLOOD WATCH HAS BEEN ISSUED UNTIL 800 PM
MST FOR ALL OF YAVAPAI COUNTY AND THE SOUTHWEST PORTION OF COCONINO
COUNTY. THINK THERE WILL BE ANOTHER ROUND OF NOCTURNAL STORMS BUT
WILL BE MORE FOCUSED OVER THE EASTERN HALF OF THE LITTLE COLORADO
RIVER VALLEY...THE EASTERN MOGOLLON RIM...WHITE MOUNTAINS AND
NORTHERN GILA COUNTY. THIS IS BECAUSE THE DEEPER MOISTURE AXIS WILL SHIFT
TO THE EAST TODAY AND A FAIRLY SIGNIFICANT AREA OF LOW INERTIAL
STABILITY IN THE UPPER LEVELS WILL REMAIN THROUGH THE NIGHT. FOR
SATURDAY...WITH SOME DRYING OVER THE WEST...WOULD EXPECT A MORE
DIURNAL TREND TO CONVECTION AND SOMEWHAT LESS ACTIVITY (ALTHOUGH IT
REMAINS MOIST AND MID LEVEL LAPSE RATES REMAIN FAVORABLE). OVER
CENTRAL AND EASTERN PORTIONS EXPECT SCATTERED TO NUMEROUS STORMS
WITH MOISTURE AXIS LOCATED ACROSS THE AREA. CURRENT FORECAST HANDLES
THIS WELL.

MCCOLLUM

.FGZ...FLASH FLOOD WATCH UNTIL 800 PM MST FOR SOUTHWEST COCONINO
       COUNTY AND ALL OF YAVAPAI COUNTY.

AZZ004>018-037>040-101930-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
930 AM MST FRI AUG 10 2001

...FLASH FLOOD WATCH UNTIL 800 PM MST FOR SOUTHWEST COCONINO COUNTY
AND ALL OF YAVAPAI COUNTY...

...SCATTERED THUNDERSTORMS TODAY ACROSS NORTHERN ARIZONA WITH THE
POTENTIAL FOR HEAVY RAINFALL...

A MOIST NORTHERLY FLOW WILL REMAIN OVER ARIZONA TODAY AND TONIGHT.
AS A RESULT...WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED.
THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN...WITH RAINFALL
AMOUNTS OF 1 TO 4 INCHES...AND THE POTENTIAL FOR LOCALIZED FLASH
FLOODING. FOR TODAY...THE MAIN THREAT OF FLOODING WILL
BE LOCATED OVER SOUTHWEST COCONINO COUNTY AND ALL OF YAVAPAI COUNTY
WHERE SOIL CONDITIONS HAVE BECOME VERY MOIST. A FLASH FLOOD WATCH
HAS BEEN ISSUED UNTIL 800 PM MST FOR THIS AREA. FOR LATE THIS AFTERNOON
AND TONIGHT THE THREAT FOR ORGANIZED HEAVY RAIN PRODUCING STORMS WILL
SHIFT TO THE EASTERN MOGOLLON RIM...NORTHERN GILA COUNTY...EASTERN
PORTIONS OF THE LITTLE COLORADO RIVER VALLEY AND THE WHITE MOUNTAINS.