Severe Thunderstorm Warning 26, NWS Tucson, AZ

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
945 AM MST WED JUL 23 2003

.SYNOPSIS...HIGH PRESSURE CENTERED OVER NEVADA WILL SLOWLY MOVE
TOWARD THE FOUR CORNERS REGION BY FRIDAY. WEAK DISTURBANCES ROTATING
AROUND THE HIGH WILL PROVIDE SCATTERED AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH FRIDAY. A SIGNIFICANT INCREASE IN SHOWERS
AND THUNDERSTORMS MAY OCCUR BY SUNDAY AS A STRONGER DISTURBANCE
MOVES TOWARD SOUTHEAST ARIZONA.

.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED MOSTLY LESS THAN 30 DBZ
ECHOES MOVING NWWD ACROSS SE PINAL COUNTY W OF I-10 AT 1630Z.
VISIBLE SATELLITE IMAGERY INDICATED GENERALLY CLEAR SKIES ACROSS SE
AZ WITH EXCEPTION OF CUMULIFORM CLOUDINESS OVER FAR WRN PIMA/SE
PINAL COUNTIES AS WELL AS THE WHITE MOUNTAINS. DEWPOINTS WERE IN THE
UPPER 50S-MID 60S F WHICH WERE NEARLY IDENTICAL TO 24 HOURS AGO.
ALSO NOTED THE SOMEWHAT DRIER ENVIRONMENT OVER SRN NM AS EVIDENCED
WITH DEWPOINTS IN THE MID 40S-NEAR 50 F. 23/12Z TUS SOUNDING
REMAINED FAIRLY MOIST WITH PRECIP WATER VALUE OF 1.40 INCH.
STABILITY PARAMETERS HAD LIFTED INDEX NEAR MINUS 6 AND UNMODIFIED
SURFACE-BASED CAPE OF 2121 J/KG WHICH WERE SIMILAR TO 24 HOURS AGO.
HOWEVER HAVE NOTED SOME DRYING IN THE SURFACE-H7 LAYER VERSUS TUE
MORNING THOUGH MOISTENING IN THE H7-H4 LAYER HAD OCCURRED. PROFILE
EXHIBITED COOLING OF AROUND 2 DEGS C IN THE H6-H4 LAYER VERSUS 24
HOURS AGO. H7-H5 WIND FLOW HAD INCREASED TO GENERALLY 25 KTS AND
ELY/SELY FLOW PREVAILED THROUGHOUT THE ENTIRE COLUMN. ANALYSES OF
UPPER AIR PLOTS INDICATED HIGH PRESSURE CENTERED OVER NE NV WITH
GENERALLY SELY FLOW ALOFT OVER AZ. AGREE WITH SWODY1 THAT DEEPLY-
MIXED BOUNDARY LAYER WILL DEVELOP AGAIN THIS AFTERNOON. SHOWERS/
THUNDERSTORMS SHOULD INITIATE WHITE/CHIRICAHUA MOUNTAINS THEN
MOVE/PROPAGATE W/NW DURING THE AFTERNOON/EVENING. LOCALLY DAMAGING
WINDS/HAIL COULD OCCUR INITIALLY WITH THE STRONGER STORMS WITH
LOCALLY HEAVY RAINS POTENTIALLY OCCURRING THEREAFTER. THE LACK OF A
READILY DISCERNABLE MID-LEVEL FORCING FEATURE SUCH AS SHORTWAVE
TROUGH/VORT MAX VIA SATELLITE IMAGERY MAY REDUCE THE POTENTIAL OF
FAIRLY ACTIVE DAY. AT ANY RATE STANDARD SEASONAL AFTERNOON/EVENING
SHOWER/THUNDERSTORM REGIME SHOULD SUFFICE. WILL ADDRESS POTENTIAL
FOR INCREASED ACTIVITY THIS WEEKEND IN AFTERNOON DISCUSSION.  BF

.TWC...NONE.

AZZ019-029>035-241400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1230 PM MST WED JUL 23 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...THUNDERSTORMS LAST NIGHT COOLED THE LOWER LAYERS OF THE
ATMOSPHERE WHICH GENERALLY LEADS TO LESS ACTIVITY ON THE FOLLOWING
DAY. THIS SHOULD CONFINE THE THUNDERSTORM ACTIVITY TO MAINLY THE
MOUNTAINS THIS AFTERNOON WITH THUNDERSTORMS MOVING INTO THE VALLEYS
THIS EVENING. NUMERICAL MODELS DO NOT INDICATE SIGNIFICANT ORGANIZED
CONVECTION TODAY...ALTHOUGH STORMS WILL PRODUCE LOCALLY HEAVY RAIN
DUE TO THE HIGH MOISTURE CONTENT OF THE ATMOSPHERE.

.DISCUSSION...TUCSON SOUNDING SIMILAR TO YESTERDAY ALTHOUGH LOW
LEVELS COOLED SOMEWHAT...ESPECIALLY PHOENIX SOUNDING WHICH DOES NOT
APPEAR ABLE TO SUPPORT SURFACED BASED STORMS. THE ONLY FACTOR THAT
MAY PUSH STORMS OFF THE MOUNTAINS IS FAIRLY STRONG MID LEVEL WINDS
OF 20 KNOTS OR SO. FIRST STORMS WILL DEVELOP...RAIN...AND MOVE OFF
MOUNTAINS AND THEN DISSIPATE AFTER THEY MOVE INTO VALLEYS. BY
EVENING...STORMS SHOULD BE ABLE TO MOVE INTO VALLEYS. AT THIS TIME
IT DOES NOT LOOK LIKE STORMS WILL PUSH MUCH FARTHER OUT IN THE
DESERTS THAN MARANA...BUT THE TUCSON VALLEY AS WELL AS THE I-19
CORRIDOR SEEM TO HAVE THE BEST POTENTIAL FOR THE HEAVIEST RAINS.

STORM MOTION WILL BE TO THE WEST TO NORTHWEST AT 15 MPH.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH WEDNESDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

SUFFICIENT MOISTURE WILL BE IN PLACE FOR A STANDARD SUMMERTIME
THUNDERSTORM SEASON FORECAST. EXPECT SCATTERED MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.