Flash Flood Warning 12, NWS Tucson, AZ

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
210 PM MST SUN AUG 13 2000

SYNOPSIS...HIGH PRESSURE WILL REMAIN NORTH OF THE AREA KEEPING A
MONSOONAL FLOW OVER SOUTHEAST ARIZONA THROUGH THE WEEK. STORMS WILL
BE AIDED BY A WEAK TROUGH SUNDAY AND MONDAY...BUT SLIGHTLY DRIER AIR
WORKING INTO FAR SOUTHEAST ARIZONA FROM NEW MEXICO MAY KEEP THE
STORMS CONFINED TO THE HIGHER TERRAIN TUESDAY AND WEDNESDAY. A WELL
ORGANIZED TROUGH IS EXPECTED TO MOVE FROM THE GULF OF MEXICO
REACHING SOUTHERN ARIZONA LATE IN THE WEEK FOR AN INCREASE IN CLOUDS
AND THUNDERSTORMS.

DISCUSSION...STORMS DEVELOPING OVER MUCH OF THE HIGHER TERRAIN OF
SOUTHEAST ARIZONA AND APPEAR DESTINED TO BECOME SCATTERED OVER MUCH
OF THE AREA DURING THE EVENING HOURS.  WINDS ARE GENERALLY QUITE
LIGHT SO THE POTENTIAL FOR LOCALLY HEAVY RAINFALL EXISTS.  MOST OF
THE ACTIVITY BEING TRIGGERED BY THE HIGHER TERRAIN BUT LARGE SCALE
ORGANIZATION FROM WEST CENTRAL NEW MEXICO TO SOUTHCENTRAL ARIZONA
ASSOCIATED WITH THE DEFORMATION ZONE NORTH OF NORTHERN MEXICO
INVERTED TROUGH.  CYCLONIC CIRCULATION IN VISIBLE SATELLITE PICTURES
OVER WESTCENTRAL ARIZONA MAY BE AIDING THE STRETCHING AHEAD OF SAID
INVERTED TROUGH.  AVN MOVES THIS FEATURE SLOWLY WEST THROUGH THE
AREA...SO DO NOT SEE A LARGE CHANGE IN CONDITIONS FOR MONDAY
AFTERNOON.  CAPE VALUES UP TODAY PER MODIFIED 12Z TUS RAOB AND 18Z
ETA TO ABOUT 1000 J/KG...PRIMARILY DUE TO THE 1 TO 2 DEGREES OF
COOLING THAT OCCURRED ABOVE 700 MB.  WILL FORECAST SCATTERED
CONVECTION IN THE LOWER ELEVATIONS THIS EVENING...AND WOULD NOT BE
SURPRISED TO SEE LOCALIZED FLASH FLOODING PER SLOW MOVEMENT AND GOOD
MOISTURE.  GOES PW IMAGERY SHOWS DRIER AIR NOW WORKING INTO THE FAR
SOUTHEAST AND THIS MAY EVENTUALLY KEEP STORMS CONFINED TO THE HIGHER
TERRAIN BY TUESDAY...BUT MODELS ARE NOT SUGGESTING A COMPLETE
SHUTDOWN IN ACTIVITY. THE EXTENDED FORECAST LOOKS VERY INTERESTING
AS DEEP MOISTURE ASSOCIATED WITH A TROPICAL WAVE IN WESTERN GULF OF
MEXICO FORECAST BY MRF AND CANADIAN MODELS TO REACH SOUTHERN ARIZONA
THURSDAY AND FRIDAY.  MRF AND CANADIAN ENSEMBLES BRING SOME OF THE
HIGHEST POPS TO ]SOUTHERN ARIZONA OF THE SUMMER...SO WILL RETURN TO
FORECAST TO SCATTERED STORMS BY THE END OF THE WEEK.  DRB

.TWC...NONE.

AZZ019-029>035-140600-
HAZARDOUS WEATHER OUTLOOK...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1045 AM MST SUN AUG 13 2000

                           *CONDITIONAL*   *CONDITIONAL*
COUNTY             AREAL    PROBABILITY  RAIN GREATER THAN   STORM
                  COVERAGE   OF SEVERE     1.00      2.00    MOTION

COCHISE              20          15         40        10     NW   5
GRAHAM               20          15         40        10     NW   5
GREENLEE             30          15         50        15     NW   5
TUCSON/ERN PIMA      15          10         30         5     NW   5
TOHONO OODHAM       10          10         25         5     NW   5
SOUTHEAST PINAL      15          10         25         5     NW   5
WESTERN PIMA         10          10         20         5     NW   5
SANTA CRUZ           20          15         40        10     NW   5

SYNOPSIS...HIGH PRESSURE CONTINUES TO COVER NORTHERN ARIZONA. THE
EASTERLY WINDS ACROSS SOUTHERN ARIZONA WILL BRING IN A BIT DRIER AIR
TODAY FOR A FEW LESS THUNDERSTORMS THAN YESTERDAY. HOWEVER THE AIR
MASS REMAINS UNSTABLE SO MAINLY MOUNTAIN THUNDERSTORMS WILL DEVELOP
BUT POTENTIAL FOR HEAVY RAIN IS NOT SO GREAT. THE CHANCE FOR HIGH
WINDS FROM THESE STORMS IS ALSO FAIRLY SMALL TODAY.

*****************************************************************
KEY...
AREAL COVERAGE - PERCENT OF COUNTY OR AREA THAT WILL EXPERIENCE
                 THUNDERSTORMS
PROB OF SEVERE - THE PROBABILITY THAT ANY ONE OF THE STORMS WILL
                 REACH SEVERE LEVELS (DAMAGING WIND AND/OR
                 LARGE HAIL)
RAIN GRTR THAN - THE PROBABILITY THAT ANY ONE OF THE STORMS WILL
                 PRODUCE RAIN EXCEEDING 1 INCH OR 2 INCHES IN
                 ANY LOCATION
STORM MOTION   - GENERAL DIRECTION TO WHICH THE STORMS WILL
                 LIKELY MOVE AND SPEED IN MPH

NOTE...
VALID TIME IS FROM 12:45 PM TO 12 MIDNIGHT OF THE DAY OF ISSUANCE.
THIS PRODUCT IS NOT TO BE USED IN PLACE OF SEVERE THUNDERSTORM OR
FLASH FLOOD WARNINGS OR WATCHES. THIS PRODUCT IS ONLY USED FOR
OUTLOOK PURPOSES. CORRESPONDING GRAPHICS MAY BE FOUND ON THE NWS
TUCSON INTERNET PAGE AT
HTTP://NIMBO.WRH.NOAA.GOV/TUCSON/SWO/SWO.SHTML

END/PRF