Severe Thunderstorm Warning 80, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
200 PM SUN SEP 16 2007

.SYNOPSIS...EXPECT SHOWERS AND THUNDERSTORMS TO BECOME MORE NUMEROUS
TODAY AND MONDAY AS A LOW PRESSURE SYSTEM MOVES THROUGH THE GREAT
BASIN. ALONG WITH THE RAIN...EXPECT BREEZY TO LOCALLY WINDY
CONDITIONS...AND COOLER TEMPERATURES. DRIER AIR WILL MOVE INTO THE
STATE TUESDAY AND WEDNESDAY...WITH BREEZY CONDITIONS AND A CHANCE
FOR SHOWERS RETURNING LATER IN THE WEEK.

&&

.DISCUSSION...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT THROUGH
7 PM MST FOR PORTIONS OF NORTHERN ARIZONA. SATELLITE AND RADAR DATA
INDICATE STORMS ARE BECOMING MORE NUMEROUS ACROSS THE REGION. EXPECT
THESE TO CONTINUE TO INTENSIFY DURING THE AFTERNOON WITH SOME STORMS
BECOMING SEVERE WITH STRONG DAMAGING WINDS...LARGE HAIL...AND HEAVY
RAIN.

A TROUGH WILL ENTER THE WESTERN REACHES OF THE GREAT BASIN LATER
TODAY...AND WILL MOVE ACROSS THE GREAT BASIN AND INTO WESTERN
COLORADO BY MONDAY EVENING. DIVQ FIELDS SHOW MODERATE DEEP-LAYER
UPWARD FORCING WILL MOVE ACROSS THE REGION OVERNIGHT AND EARLY
MONDAY IN ASSOCIATION WITH THIS TROUGH. 12 AND 18 UTC KFGZ SOUNDINGS
INDICATE THAT THE CAP HAS WEAKENED CONSIDERABLY...DEEP MOISTURE IS
IN PLACE...AND WINDS HAVE STRENGTHENED THROUGH A DEEP LAYER.

THUS...EXPECT A GOOD CHANCE OF CONVECTION TODAY...AND LASTING
THROUGH LATE MONDAY. RAIN COULD BE HEAVY AT TIMES TONIGHT AND EARLY
MONDAY AS THE DYNAMICAL PORTION OF THE TROUGH MOVES THROUGH.
TRAINING STORMS RESULTING IN EXCESS PCPN AMOUNTS COULD ALSO BE AN
ISSUE WITH LAYERED SOUTHWEST FLOW APPROACHING 40 KNOTS. IN
ADDITION...ENOUGH INSTABILITY AND DEEP LAYER SHEAR IS PRESENT FOR
SOME STORMS TO BECOME SEVERE WITH STRONG WINDS AND HAIL POSSIBLE.

MUCH DRIER AND MORE STABLE AIR FOLLOWS THIS TROUGH FOR CLEARING
CONDITIONS TUESDAY AND WEDNESDAY. ANOTHER STRONGER LOW WILL DROP
DOWN THE WEST COAST LATER IN THE WEEK...RESULTING IN BREEZY AND
COOLER  CONDITIONS ACROSS ARIZONA. THIS NEXT LOW MAY ALSO TAP
MOISTURE TO  OUR SOUTH...FOR A RENEWED CHANCE OF SHOWERS BY DAYS
FIVE  THROUGH SEVEN. MODELS CONTINUE TO EXHIBIT LARGE RUN-TO-RUN
VARIABILITY IN THE TIMING AND TRACK OF THIS SYSTEM. FOR NOW...HAVE
SOME LOW CHANCES OF SHOWERS AND THUNDERSTORMS.  DB

&&

.AVIATION...FOR THE 00Z PACKAGE...EXPECT SCT-BKN CLOUD COVER AT
11-14 KFT MSL WITH A CHANCE FOR SCT TO NUMEROUS TSRA AND SHRA.
FLIGHT CONDITIONS WILL BE PRIMARILY VFR WITH OCCASIONAL MVFR IN THE
STRONGEST STORMS. OTHER THAN THUNDERSTORMS THE STRONG BREEZY WINDS
WILL BE THE PRIMARY THREAT TO AVIATION THIS AFTERNOON AND EVENING
WITH SOUTHWEST  WIND SPEEDS AROUND 10-20 KTS AND GUSTS AROUND 35
KTS. WINDS WILL BE  ERRATIC AND GUSTY NEAR THUNDERSTORMS. SHOWER AND
THUNDERSTORM  CHANCES WILL CONTINUE THROUGH THE EVENING HOURS.
AVIATION DISCUSSION  NOT UPDATED FOR AMENDMENTS.  RB
&&

.FGZ WATCHES/WARNINGS/ADVISORIES...SVR THUNDERSTORM WATCH 670 IN
EFFECT THROUGH 7 PM MST FOR ZONES 004>010-012-013-015-016-037>040.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1145 AM MST SUN SEP 16 2007

AZZ004>018-037>040-170700-
WESTERN MOGOLLON RIM-GRAND CANYON COUNTRY-YAVAPAI COUNTY MOUNTAINS-
YAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONS-
MARBLE AND GLEN CANYONS-KAIBAB PLATEAU-COCONINO PLATEAU-
NORTHEAST PLATEAU AND MESAS HWY 264 NORTHWARD-
NORTHEAST PLATEAU AND MESAS SOUTH OF HWY 264-
CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
BLACK MESA AREA-LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
EASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTY-
1145 AM MST SUN SEP 16 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...NORTHERN
GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN ARIZONA.

.DAY ONE...TODAY

A TROUGH OF LOW PRESSURE WILL INTERACT WITH DEEP MOISTURE FROM
MEXICO TODAY...CAUSING AN OUTBREAK OF POTENTIALLY SEVERE WEATHER.
EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP RAPIDLY AFTER 9 AM MST
THIS MORNING...BECOMING MORE FREQUENT AND WIDESPREAD BY THE
AFTERNOON.

THE STRONGEST AND MOST FREQUENT STORMS WILL BE OVER CENTRAL AND
WESTERN PORTIONS OF THE FORECAST AREA...INCLUDING MUCH OF YAVAPAI
AND COCONINO COUNTIES. THE STRONGER STORMS IN THESE AREAS WILL BE
CAPABLE OF PRODUCING TORRENTIAL RAINS AND LARGE HAIL...AS WELL AS
DAMAGING WINDS. A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 7 PM
MST.

THERE WILL BE A MODEST THREAT OF FLOODING TODAY DUE TO THE STORMS
REDEVELOPING AND AFFECTING THE SAME AREAS MULTIPLE TIMES THROUGH THE
AFTERNOON.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THE SAME LOW PRESSURE SYSTEM WILL CAUSE STRONG STORMS TO CONTINUE
OVERNIGHT AND INTO MONDAY. THE BEST AREA FOR THUNDERSTORMS WILL
SHIFT SLOWLY EAST TO THE NEW MEXICO BORDER BY MONDAY AFTERNOON.

.SPOTTER INFORMATION STATEMENT...

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