Severe Thunderstorm Warning 3, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-192245-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1013 AM MST MON JUN 19 2000

.SYNOPSIS...
MOISTURE-LADEN AIR FROM THE GULF OF CALIFORNIA HAS OVERSPREAD
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA. THIS WILL LEAD TO
AFTERNOON AND EVENING THUNDERSTORMS OVER PORTIONS OF SOUTH CENTRAL
ARIZONA THROUGH WEDNESDAY.

.DISCUSSION...
FORECAST CHALLENGE TODAY AGAIN FOCUSED ON CONVECTIVE STORM THREAT.
ATMOSPHERE STILL MOIST IN SFC-600 MB LAYER OVER EASTERN HALF OF
CWA...WITH P-WATER OF 1.33 INCH ON PHX SOUNDING...AND 1.09 INCH AT
YUMA. SATELLITE P-WATER MAX IN EXCESS OF 1.5 INCHES LIES WITHIN THE
NOT-SO-FAMOUS PHX-GBN-TUS TRIANGLE AS OF 7 AM. MOISTURE CONTINUES TO
STREAM NORTH FROM THE GULF OF CALIFORNIA...WITH 20 KT SOUTHERLY FLOW
THROUGH LOWEST 4K FT FROM KYUX VWP...AND THIS FLOW HAS PERSISTED
WITHOUT A CLEAR CUT BREAK SINCE JUNE 15. 24-HR P-WATER DIFFERENCE
SHOWS AZ PTN OF CWA MORE MOIST THAN SUNDAY. NO CAPE EXHIBITED ON PHX
SOUNDING...BUT SATELLITE ESTIMATES INDICATE 1000-1500 J/KG EXIST OVER
AND SOUTHEAST OF PHX...AND TUCSON SOUNDING EXHIBITED UNUSUALLY LARGE
CAPE...OVER 2500 J/KG! CONVECTIVE TEMP VERY LIKELY TO BE REACHED
TODAY...A BIT EARLIER THAN YESTERDAY...SINCE VALUE ONLY IN MID 90S.
SO...MOISTURE AND INSTABILITY IN PLACE AND CONVECTIVE TEMP WELL
WITHIN REACH.

DYNAMICALLY...STILL IN RIGHT REAR QUAD OF 250 MB JET STREAK CENTERED
OVER SW COLORADO THIS MORNING...AND TSTMS CONTINUE TO DEVELOP EAST
AND SOUTHEAST OF OUR CWA. WELL DEFINED DEEP LAYERED TROUGH OVER
SOUTHEAST CALIFORNIA THIS MORNING...WITH SW FLOW AT 700 MB FLOW AND W
FLOW AT 500 MB. DRIER AIR WORKING ITS WAY NORTHEAST IN 700-600 MB
LAYER THIS MORNING. STRONGER LOWER-MID TROPOSPHERIC WINDS IN
PLACE...BUT SW FLOW CLIMATOLOGICALLY UNFAVORABLE FOR DESERT TSTM
DVLPMNT.

ALL THINGS CONSIDERED...WITH P-WATER TRENDING UP...CAPE MUCH LARGER
THAN YESTERDAY...AND STRONGER FLOW ALOFT WITH DECENT UNIDIRECTIONAL
SHEAR...WILL HILITE THREAT FOR HAZARDOUS WEATHER OVER EASTERN QUARTER
OF CWA...MAINLY EAST OF A WICKENBURG-GILA BEND LINE...AGAIN THIS
AFTERNOON AND EVENING. STORMS WILL LIKELY 9PACK MORE OF A PUNCH THAN
WHAT OCCURRED SUNDAY EVENING...AND SOME COULD BE SEVERE. DG

N

AZZ022>024-027-028-200700-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1121 AM MST MON JUN 19 2000

...SLIGHT RISK FOR HAZARDOUS WEATHER OVER CENTRAL AND EASTERN
MARICOPA...NORTHERN PINAL...AND SOUTHERN GILA COUNTIES THIS
AFTERNOON AND TONIGHT...

THE SLIGHT RISK AREA INCLUDES THAT PORTION OF SOUTH-CENTRAL
ARIZONA ALONG AND EAST OF A LINE EXTENDING FROM WICKENBURG TO
GILA BEND. THE GREATER PHOENIX METROPOLITAN AREA IS INCLUDED IN
THE SLIGHT RISK AREA...AS ARE CASA GRANDE...FLORENCE...COOLIDGE...
APACHE JUNCTION...SUPERIOR...GLOBE...AND MIAMI. THE GREATEST THREATS
FROM STORMS...IN ADDITION TO CLOUD TO GROUND LIGHTNING...WILL BE THE
POTENTIAL FOR BRIEF BUT LOCALLY HEAVY RAIN...VERY STRONG WINDS...AND
DENSE BLOWING DUST.

THE AIRMASS OVER SOUTHWEST ARIZONA HAS BECOME MORE MOIST THAN WAS
THE CASE SUNDAY...AND MOISTURE CONTINUES TO STREAM NORTH AND EAST
FROM THE GULF OF CALIFORNIA AND NORTHERN MEXICO. ALSO...THE
ATMOSPHERE IS MORE UNSTABLE OVER SOUTH-CENTRAL AND SOUTHEAST
ARIZONA TODAY. ALL THESE FACTORS INCREASE THE CHANCE FOR
ISOLATED SEVERE THUNDERSTORMS OVER THE SLIGHT RISK AREA THIS
AFTERNOON AND EARLY TONIGHT. STORMS ARE LIKELY TO DEVELOP A LITTLE
EARLIER TODAY THAN WHAT OCCURRED SUNDAY...WITH SOME STORMS IN THE
CENTRAL DESERT SOUTH AND EAST OF PHOENIX BY EARLY THIS AFTERNOON.

THE HAZARDOUS WEATHER OUTLOOK GIVES PRELIMINARY INFORMATION FOR THE
POSSIBILITY OF WEATHER THAT COULD BECOME SEVERE...DAMAGING WINDS IN
EXCESS OF 57 MPH...DENSE BLOWING DUST WITH VISIBILITY AT OR BELOW
1/4 MILE...HAIL 3/4 INCH IN DIAMETER OR LARGER... AND HEAVY RAINFALL
THAT COULD CAUSE FLOODING OR RUNNING WASHES.  WHEN SEVERE WEATHER OR
FLOODING BEGINS... IMPORTANT LIFE SAVING INFORMATION WILL BE
PROVIDED IN SHORT TERM FORECASTS...SEVERE WEATHER AND FLOOD
WARNINGS...AND IN FOLLOW-UP STATEMENTS.

STORM SPOTTER ACTIVATION MAY BE NECESSARY LATER TODAY.

DG

N