Severe Thunderstorm Warning 18, NWS Tucson, AZ

000 
WWUS55 KTWC 070152
SVSTWC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
652 PM MST SUN JUL 6 2008

AZC023-070200-
/O.CON.KTWC.SV.W.0018.000000T0000Z-080707T0200Z/
SANTA CRUZ AZ-
649 PM MST SUN JUL 6 2008

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM MST 
FOR SOUTHERN SANTA CRUZ COUNTY...

AT 649 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR PATAGONIA LAKE...OR 9 
MILES NORTHEAST OF NOGALES...MOVING SOUTHWEST AT 13 MPH.

ALTHOUGH THE OTHER SEVERE STORM SOUTHEAST OF NOGALES...IN SONORA 
MEXICO...WEAKENED IT WILL STILL BE CAPABLE OF PRODUCING WIND GUSTS 
ACROSS NOGALES OF 40 TO 50 MPH.

LAT...LON 3135 11113 3135 11115 3138 11122 3162 11093
      3162 11058 3133 11070 3133 11109
TIME...MOT...LOC 0149Z 051DEG 11KT 3145 11085

$$

000 
WWUS55 KTWC 070159
SVSTWC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
659 PM MST SUN JUL 6 2008

AZC023-070208-
/O.EXP.KTWC.SV.W.0018.000000T0000Z-080707T0200Z/
SANTA CRUZ AZ-
658 PM MST SUN JUL 6 2008

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN SANTA CRUZ COUNTY
WILL EXPIRE AT 700 PM MST...

THE THUNDERSTORM ACROSS SOUTHERN SANTA CRUZ COUNTY HAS FALLEN BELOW 
SEVERE LEVELS. THEREFORE...THE SEVERE THUNDERSTORM WARNING HAS BEEN 
ALLOWED TO EXPIRE AT 700 PM MST.

LAT...LON 3135 11113 3135 11115 3138 11122 3162 11093
      3162 11058 3133 11070 3133 11109
TIME...MOT...LOC 0158Z 051DEG 11KT 3143 11088

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
142 PM MST SUN JUL 6 2008

.SYNOPSIS...AVAILABLE MOISTURE COMBINED WITH DAYTIME HEATING WILL
GENERATE ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS
THE NEXT FEW DAYS. HIGH TEMPERATURES WILL BE RUNNING NEAR NORMAL FOR
JULY THROUGH THE WEEK. A BROAD AREA OF HIGH PRESSURE ALOFT WILL
RESULT IN A STRONGER EAST TO SOUTHEAST STEERING FLOW BY LATE IN THE
WEEK. THIS SHIFT IN THE PATTERN WILL BRING AN INCREASE IN
THUNDERSTORM ACTIVITY BY THURSDAY.

&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWS WEAK HIGH PRESSURE EXTENDING
FROM EXTREME SOUTHEAST ARIZONA/NORTHERN MEXICO TO NORTHERN TEXAS AND
SW OKLAHOMA. MEANWHILE...A TROUGH OVER NEVADA IS MOVING EAST AND
WILL MAKE ITS WAY INTO THE PLAINS ON MONDAY. IR AND VISIBLE
SATELLITE IMAGERY INDICATE THAT THE SOLID DECK OF MID LEVEL CLOUDS
OVER A LARGE PORTION OF MY FORECAST AREA THIS MORNING HAS ERODED.
CURRENT SATELLITE IMAGES SHOW A FAIRLY TYPICAL MONSOON DAY WITH
BUILDS UPS OVER THE MOUNTAINS.

THIS MORNINGS KTWC SOUNDING WITHOUT MODIFICATION SHOWED A PWAT OF
1.64 INCHES...A LIFTED INDEX OF MINUS 8 AND A CAPE OF AROUND 3400
J/KG. MODIFYING THE SOUNDING USING T=100TD=57 YIELDS A PW OF 1.55
INCHES...A LIFTED INDEX OF MINUS 6 AND A CAPE OF AROUND 1600 J/KG
ASSUMING THE PARCEL IS LIFTED FROM THE SURFACE. THE MEAN TEMP
LIFTING METHOD YIELDS A CAPE OF AROUND 1400 J/KG. WINDS IN THE
COLUMN WERE ALMOST NON-EXISTENT WITH VERY WEAK FLOW FROM AROUND
700-375MB. WITH THAT SAID...EXPECT THE STORMS THAT DO DEVELOP TODAY
TO BE MAINLY HEAVY RAINERS WITH LITTLE MOVEMENT OR PERHAPS A SLOW
DRIFT TO THE WEST.

MODELS INDICATE THE HIGH WILL MOVE FARTHER EAST AS THE TROUGH WHICH
IS CURRENTLY OVER NEVADA CONTINUES TO PUSH EAST REACHING THE CENTRAL
PLAINS AND DRAPED ACROSS NEW MEXICO BY MONDAY. AS THIS OCCURS A
DOUBLE CENTERED HIGH WILL SET-UP WITH ONE HIGH PRESSURE CELL OVER
THE PACIFIC WATERS AND EXTENDING INTO NW ARIZONA ON TUESDAY. THE
OTHER HIGH WILL BE CENTERED OVER THE DIXIE STATES AND EXTENDING BACK
INTO WEST TEXAS. BETWEEN THESE TWO HIGH CELLS WILL RESIDE A COL OVER
NEW MEXICO. THIS CONFIGURATION WILL PERSISTS FOR A FEW DAYS PROVING
A LOW END CHANCE OF POPS FOR MOST LOCATIONS WITH HIGHER CHANCES OVER
MOUNTAIN TOPS. BY LATE NEXT WEEK....BOTH THE GFS AND ECMWF SHOW AN
INVERTED TROUGH MOVING WEST THROUGH NORTHERN MEXICO ON THURSDAY AND
EVENTUALLY INTO THE DESERT SOUTHWEST ON FRIDAY. THIS WILL LIKELY
ENHANCE STORM DEVELOPMENT LATE IN THE WEEK AND INTO THE WEEKEND. I
THEREFORE INCREASED RAIN CHANCES FOR THIS PERIOD...BUT PERHAPS NOT
ENOUGH. SUBSEQUENT SHIFTS WILL HAVE AMPLE TIME TO MASSAGE THE
FORECAST BASED ON FRESH MODEL RUNS.

HIGHS THROUGH THE PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
LOWS WILL REMAIN SEVERAL DEGREES ABOVE NORMAL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...HIGH PRESSURE ALOFT WILL REMAIN CENTERED NORTHWEST
OF US THROUGH THE MIDDLE OF NEXT WEEK. FLOW AROUND THIS HIGH WILL
RESULT IN A DAILY CYCLE OF AFTERNOON AND EVENING THUNDERSTORMS. A
FAIRLY ACTIVE PERIOD LOOKS TO BE IN STORE FOR SOUTHERN ARIZONA THIS
WEEK AS ADDITIONAL MOISTURE COUPLED WITH SOME DISTURBANCES MOVING
INTO THE AREA FROM MEXICO LATE IN THE WEEK AND INTO THE WEEKEND. ANY
THUNDERSTORMS THAT DO DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE
STRONG...ERRATIC...AND GUSTY WINDS.

&&

.AVIATION...ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON AND EVENING. WINDS WILL GENERALLY BE LIGHT AND DIURNALLY
DRIVEN EXCEPT NEAR THUNDERSTORMS THROUGH 06Z MON...WHERE WINDS WILL
BE VARIABLE AND GUSTY AT TIMES. OUTFLOW WINDS WITH STORMS COULD HAVE
GUSTS TO AROUND 35 KTS. THE MAIN FOCUS WITH STORMS THIS AFTERNOON
AND EVENING WILL BE HEAVY RAIN. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

MOLLERE

WEATHER.GOV/TUCSON