Severe Thunderstorm Warning 39, NWS Tucson, AZ

000 
WWUS55 KTWC 210034
SVSTWC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
534 PM MST THU AUG 20 2009

AZC003-210100-
/O.CON.KTWC.SV.W.0039.000000T0000Z-090821T0100Z/
COCHISE AZ-
534 PM MST THU AUG 20 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM MST 
FOR WEST CENTRAL COCHISE COUNTY...INCLUDING SIERRA VISTA...

AT 529 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH...LOCALLY HEAVY DOWNPOURS AND SMALL HAIL. THE 
STRONGEST PART OF THE STORM WAS MOVING WEST AT 10 MPH THROUGH 
EASTERN SECTIONS OF SIERRA VISTA NEAR AND JUST NORTH OF THE 
INTERSECTION OF STATE HIGHWAY 90 AND 92.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
WHETSTONE...HUACHUCA CITY AND FORT HUACHUCA

LAT...LON 3177 11003 3145 11009 3151 11044 3174 11044
TIME...MOT...LOC 0029Z 084DEG 10KT 3160 11020

$$

000 
WWUS55 KTWC 210100
SVSTWC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
600 PM MST THU AUG 20 2009

AZC003-210109-
/O.EXP.KTWC.SV.W.0039.000000T0000Z-090821T0100Z/
COCHISE AZ-
600 PM MST THU AUG 20 2009

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL COCHISE COUNTY
WILL EXPIRE AT 600 PM MST...

THE STORM THAT PROMPTED THE SEVERE THUNDERSTORM WARNING HAD MOVED 
WEST OF SIERRA VISTA AND WAS NO LONGER EXPECTED TO PRODUCE WINDS IN 
EXCESS OF 58 MPH. THUS...THE WARNING WILL EXPIRE ON TIME. 

LAT...LON 3177 11003 3145 11009 3151 11044 3174 11044
TIME...MOT...LOC 0059Z 084DEG 10KT 3159 11030

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
217 PM MST THU AUG 20 2009

.SYNOPSIS...HIGH PRESSURE ALOFT OVER NEW MEXICO WILL BRING A MOIST
SOUTHERLY FLOW ALONG WITH A CHANCE OF SHOWERS AND THUNDERSTORMS TO
THE AREA STARTING FRIDAY AND CONTINUING THIS WEEKEND INTO EARLY NEXT
WEEK.

&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWS A LARGE HIGH CENTERED OVER
THE GREAT BASIN AND THE TAIL END OF A BACK DOOR FRONT OFF TO THE
EAST ACROSS WEST TEXAS AND SOUTHERN NEW MEXICO. A DEFORMATION ZONE
CAN BE SEEN IN VISIBLE SATELLITE IMAGERY ACROSS NE SONORA AND
NORTHERN CHIHUAHUA MEXICO. EXPECTING STORMS TO DEVELOP AGAIN TODAY
UNDER THIS COL WITH THE BEST THREAT FOR STORMS ALONG THE
INTERNATIONAL BORDER...BUT ALSO EXTENDING A BIT FARTHER NORTH THAN
WHAT OCCURRED YESTERDAY. STEERING FLOW TODAY SHOULD BE FROM THE EAST
TO NORTHEAST...SO SHOWERS AND STORMS WILL SPREAD WEST OR SOUTHWEST
TODAY INSTEAD OF SOUTH.

THIS MORNINGS UNMODIFIED KTWC SOUNDING SHOWED A PWAT OF 1.12
INCHES...A LIFTED INDEX OF MINUS 5 AND A CAPE OF AROUND 1900 J/KG.
MODIFYING THE SOUNDING USING T=101TD=48 YIELDS A LIFTED INDEX OF
MINUS 2 AND A CAPE OF AROUND 900 J/KG. WITH THAT SAID...THE NIGHT
SHIFT INCREASED POPS A BIT...SO EXPECTING ONLY ISOLATED SHOWERS AND
THUNDERSTORMS FOR MOST DESERT AND VALLEY LOCATIONS WITH SLIGHTLY
HIGHER POPS FOR THE MOUNTAINS. RADAR MOSAIC IS CURRENTLY DETECTING
ISOLATED SHOWERS ALONG THE SANTA CRUZ AND COCHISE COUNTY LINE NEAR
PARKER CANYON LAKE...AND ALSO IN EASTERN COCHISE COUNTY NEAR THE
CHIRICAHUA MOUNTAINS.

THE SOUNDING ALSO SHOWED GENERALLY EASTERLY WINDS FROM AROUND 600MB
AND ABOVE. THE HIGH CONTINUES TO MOVE EAST AS THE UPPER LOW OVER THE
SOUTHERN GULF OF CALIFORNIA SLOWLY MOVES WEST OVERNIGHT AND INTO
FRIDAY. AS THIS OCCURS THE GRADIENT WILL TIGHTEN OVER NORTHERN
MEXICO AND SRN ARIZONA WITH MID LEVEL FLOW BECOMING EAST SOUTHEAST
WITH A VERY LONG FETCH FROM THE GULF OF MEXICO. IN ADDITION...THE
NAM BUFR SOUNDING SHOWS PWAT VALUES OF AROUND AN INCH AND A HALF ON
FRIDAY WITH A LIFTED INDEX OF MINUS 9 AND A CAPE OF OVER 3000 J/KG
DURING THE LATE MORNING HOURS. DURING THE AFTERNOON HOURS THE PWATS
CLIMB TO AROUND 1.60 - 1.8 INCHES WITH LIFTED INDICES AROUND MINUS 4
TO 6 AND CAPE VALUES OF AROUND 1200-1700 J/KG. THE GFS BUFR SOUNDING
IS NOT NEAR AS DRAMATIC. ALTHOUGH BOTH MODELS SHOW INCREDIBLE
INSTABILITY AND CAPE OVERNIGHT TONIGHT AND FRIDAY NIGHT...BUT WILL
DISCOUNT ANYTHING SEVERE OCCURRING DURING THOSE HOURS DO TO THE LACK
OF DAYTIME HEATING. HOWEVER...WITH BOTH THE GFS AND ECMWF SHOWING A
COUPLE OF FAIRLY STRONG VORT MAXIMA MOVING THROUGH SRN ARIZONA CANT
COMPLETELY DISCOUNT SOMETHING HAPPENING OVERNIGHT FRIDAY INTO EARLY
SATURDAY. THE MODEL SOUNDINGS ALSO SHOW PLENTY OF SPEED SHEAR ON
FRIDAY WITH ABOUT 30-35 KNOTS DURING THE LATE AFTERNOON AND INTO THE
EVENING HOURS. SPC HAS HIGHLIGHTED SRN ARIZONA IN A SEE TEXT MODE.
BASICALLY LOOKING AT SOME STORMS APPROACHING SEVERE LIMITS WITH THE
MAIN THREAT TOMORROW BEING STRONG DOWNBURST WINDS.

I MADE SOME SIGNIFICANT CHANGES TO THE POP FORECAST TO MAINLY
INCREASE POPS OUT WEST ON FRIDAY AND SATURDAY. THE BOTTOM LINE IS
THAT THIS WILL BE THE BEST SHOT FOR RAIN THAT WE HAVE SEEN IN A
WHILE. SO FRIDAY THROUGH MONDAY LOOKS PRETTY GOOD FOR SEEING AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST OF MY FORECAST
AREA. BY THE EARLY TO MIDDLE OF NEXT WEEK POPS WILL BE CONFINED TO
MAINLY CENTRAL AND EASTERN ZONES...AND MAINLY JUST A LOW GRADE POP
FORECAST BY THEN AS THE PACIFIC LOW HELPS TO PUSH MOISTURE BACK TO
THE EAST.

&&

.AVIATION...THERE IS ENOUGH MOISTURE IN PLACE FOR PARTLY CLOUDY
SKIES DURING THE AFTERNOON AND EVENING HOURS...AS CUMULUS CLOUDS
DEVELOP IN THE DAYTIME HEATING WITH CLOUD BASES BETWEEN 5-9 KFT AGL.
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED LATE THIS AFTERNOON
AND EVENING...WITH GUSTY OUTFLOWS TO NEAR 45 KNOTS WITH ANY
CONVECTION THAT DOES DEVELOP. OTHERWISE...NORMAL DIURNAL WIND TRENDS
ARE EXPECTED. DEEPER MOISTURE IS EXPECTED TO PUSH INTO SOUTHEAST
ARIZONA ON FRIDAY...LASTING THROUGH THE WEEKEND...FOR AN INCREASE IN
CLOUD COVER AND PRECIPITATION CHANCES. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...THERE WILL BE ISOLATED SHOWERS AND THUNDERSTORMS
SOUTHEAST OF A LINE FROM SELLS...TO SAFFORD...TO HANNAGAN MEADOW
THIS AFTERNOON AND EVENING...WITH DRY CONDITIONS PREVAILING ACROSS
THE REST OF SOUTHEAST ARIZONA. MORE WIDESPREAD PRECIPITATION CHANCES
ARE THEN POSSIBLE FRIDAY...THROUGH THE WEEKEND...AS THE UPPER HIGH
SHIFTS INTO A MORE FAVORABLE LOCATION FOR IMPORTING MOISTURE INTO
SOUTHEAST ARIZONA. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO
CONTINUE INTO FRIDAY.

&&

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

PUBLIC...MOLLERE
FIRE WEATHER/AVIATION...GZ

WEATHER.GOV/TUCSON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
855 AM MST THU AUG 20 2009

AZZ019-029>035-210200-
NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY-UPPER GILA RIVER
VALLEY-WESTERN PIMA-TOHONO OODHAM NATION-TUCSON METRO/MARANA/GREEN
VALLEY-SANTA CRUZ COUNTY-COCHISE COUNTY-
855 AM MST THU AUG 20 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA
AND SOUTH CENTRAL ARIZONA.

.DAY ONE...TODAY AND TONIGHT

EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE
EVENING HOURS TONIGHT...WITH THE HIGHEST CHANCES FOR PRECIPITATION
ALONG THE INTERNATIONAL BORDER. ISOLATED HEAVY RAINFALL AND GUSTY
WINDS TO AROUND 45 MPH CAN BE EXPECTED WITH THE STRONGEST STORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME. DEEPER MOISTURE IS
EXPECTED TO MOVE BACK INTO SOUTHEAST ARIZONA FROM THE SOUTH AND EAST
FRIDAY THROUGH SUNDAY...RESULTING IN SCATTERED SHOWERS AND STORMS
AREAWIDE. SOME DRYING WILL TAKE PLACE EARLY NEXT WEEK WHICH WILL
KNOCK THE CHANCES FOR PRECIPITATION BACK DOWN TO ISOLATED LEVELS.

.SPOTTER INFORMATION STATEMENT...

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

WEATHER.GOV/TUCSON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
456 PM MST THU AUG 20 2009

AZZ035-210045-
COCHISE COUNTY AZ-
456 PM MST THU AUG 20 2009

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN COCHISE COUNTY UNTIL
545 PM MST...

AT 452 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
CLUSTER OF STRONG THUNDERSTORMS PASSING THROUGH THE HEREFORD AND
BENSON AREAS. THESE STORMS WERE MOVING WEST AT 10 MPH.

LOCALLY HEAVY DOWNPOURS AND WIND GUSTS UP TO 50 MPH ARE EXPECTED
WITH SOME OF THESE STORMS AS THEY MOVE THROUGH THE AREA IMPACTING
PARTS OF SIERRA VISTA AND BENSON.

AREAS AFFECTED BY THIS STORM INCLUDE...SIERRA VISTA...BENSON...
HUACHUCA CITY...HEREFORD...NICKSVILLE...CORONADO NATIONAL MEMORIAL...
KARTCHNER CAVERNS STATE PARK...RAMSEY CANYON PRESERVE...FORT
HUACHUCA...WHETSTONE AND MESCAL.

LAT...LON 3135 11044 3202 11045 3204 11019 3134 11009
TIME...MOT...LOC 2353Z 083DEG 8KT 3145 11017