Severe Thunderstorm Warning 93, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
950 AM MST SUN AUG 30 2015

.SYNOPSIS...DEEPER MOISTURE WILL BRING A MORE ACTIVE DAY TO THE
REGION TODAY...WITH AN ENHANCED THREAT OF ISOLATED SEVERE STORMS.
SOUTHWEST FLOW WILL BEGIN TO PUSH STORM ACTIVITY EASTWARD ON
MONDAY AND TUESDAY...EVENTUALLY LIMITING STORMS TO THE FAR
EASTERN BORDER BY LATE IN THE WEEK.

&&

.DISCUSSION...THIS MORNINGS VISIBLE SATELLITE IMAGERY REVEALS
MOSTLY CLEAR TO PARTLY CLOUDY SKIES ACROSS MOST OF NORTHERN
ARIZONA. SOME PATCHES OF DENSE CUMULIFORM CLOUD ARE PRESENT. THIS
IS LIKELY DUE TO A COMBINATION OF INCREASING LOW LEVEL MOISTURE
AND OROGRAPHICS, AND FORCING FROM A WEAK UPPER LEVEL SHORTWAVE
TROUGH CROSSING THE REGION TODAY FROM THE SOUTHWEST TO NORTHEAST.

OBSERVED DUE POINTS REVEAL SURFACE MOISTURE IS UP A BIT SINCE THIS
TIME YESTERDAY, ESPECIALLY IN FAR NORTHEAST ARIZONA. IN GENERAL,
DEW POINTS FROM THE UPPER 40'S TO THE LOW 60'S HAVE OVERSPREAD THE
REGION. THE GREATEST VALUES HAVE BEEN OBSERVED ACROSS THE LOW
DESERTS OF YAVAPAI COUNTY.

MODEL DATA SUGGEST THE GREATEST INSTABILITY WILL DEVELOP ALONG AND
SOUTH OF THE MOGOLLON RIM TODAY. MODIFIED OBSERVED AND FORECAST
UPPER AIR SOUNDINGS FROM FLAGSTAFF PREDICT THAT AROUND 600 J/KG
OF SURFACE BASED CAPE WILL DEVELOP BY LATE MORNING ALONG THE
CENTRAL MOGOLLON RIM. THE GREATEST INSTABILITY WILL LIEKLY DEVELOP
ACROSS YAVAPAI COUNTY - WHERE THE GREATEST LOW LEVEL MOISTURE
RESIDES. DEEP LAYER BULK SHEAR IS FORECAST TO BE SOMEWHAT LOW
TODAY, WITH 15 KNOTS OR LESS EXPECTED. STORM MOTION WILL
GENERALLY BE FROM THE SOUTHWEST TO NORTHEAST AROUND 10 TO 15
KNOTS.

THIS MORNINGS HI-RES MODEL RUNS GENERALLY AGREE THAT TODAY WILL BE
CONVECTIVELY ACTIVE. THIS SEEMS REASONABLE GIVEN THE ABOVE
ANALYSIS. IN ADDITION, THERE ARE SOME INDICATIONS THAT SHOWER AND
THUNDERSTORM ACTIVITY MAY EXTEND INTO THE EVENING AND OVERNIGHT
HOURS, ESPECIALLY SOUTH OF THE MOGOLLON RIM.

IN TERMS OF UPDATES, ONLY A FEW MINOR CHANGES TO INCREASE THE CHANCES
FOR SHOWERS AND THUNDERSTORMS WERE MADE FOR TODAY THROUGH THIS
EVENING.

&&

.PREV DISCUSSION /320 AM MST/...HIGHER PW VALUES AS WELL AS
IMPROVED DYNAMICS AND SHEAR WILL COME TOGETHER THIS
AFTERNOON...DELIVERING A FAR GREATER POTENTIAL FOR SEVERE STORMS
WHEN COMPARED TO SATURDAY. THIS AIRMASS WILL SLOWLY PUSH EAST ON
MONDAY...WITH THE STRONGEST STORM POTENTIAL SHIFTING ROUGHLY TO A
LINE FROM I-17 EASTWARD.

THE REMAINDER OF THE WEEK FEATURES STEADILY DRIER SOUTHWEST
FLOW...WHICH WILL EVENTUALLY LIMIT STORM COVERAGE TO THE EASTERN
BORDER BY WEDNESDAY OR THURSDAY. ALONG WITH THE DRIER AIR WILL
COME COOLER TEMPERATURES AS A LONG WAVE TROUGH DEVELOPS TO OUR
NORTH...ALONG WITH GUSTY DAYTIME SOUTHWEST WINDS.

&&

.AVIATION...FOR THE 18Z PACKAGE...EXPECT INCREASING
COVERAGE/INTENSITY OF SHRA/TSRA THIS AFTERNOON...WITH MVFR
CIG/IFR VSBY AND GUSTY WINDS IN THE STRONGEST STORMS. STORM MOTION
TOWARD THE NORTHEAST. COVERAGE DIMINISHING AFT 03Z MONDAY...WITH
ISOLD - SHRA THEREAFTER. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

PUBLIC...RR/BOHLIN
AVIATION...BAK

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
356 AM MST SUN AUG 30 2015

AZZ004>018-037>040-310330-
KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY-
COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS-
NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY-
CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS-
NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS-
OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA-
NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-
356 AM MST SUN AUG 30 2015

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

.DAY ONE...TODAY AND TONIGHT

HIGHER MOISTURE VALUES AND A MORE UNSTABLE AIRMASS WILL BRING AN
ACTIVE DAY TO THE REGION TODAY. THE THREAT FOR LOCALLY HEAVY
RAINFALL AND HAIL WILL BE ENHANCED...WHEN COMPARED TO SATURDAY.

PRIMARY THREATS TODAY WILL BE HEAVY RAIN...GUSTY THUNDERSTORM
WINDS TO 50 MPH... LIGHTNING AND ISOLATED DAMAGING HAIL. STORM
MOTION WILL BE TO THE EAST AND NORTHEAST.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

DRIER SOUTHWEST FLOW WILL DEVELOP NEXT WEEK...WITH STORM COVERAGE
SLOWLY SHIFTING EAST TOWARD THE NEW MEXICO BORDER.

.SPOTTER INFORMATION STATEMENT...

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1059 AM MST SUN AUG 30 2015

AZZ004-006-007-301830-
KAIBAB PLATEAU-COCONINO PLATEAU-GRAND CANYON COUNTRY-
1059 AM MST SUN AUG 30 2015

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL COCONINO COUNTY...

AT 1057 AM MST...A STRONG THUNDERSTORM WAS 7 MILES WEST OF HERMITS
REST...MOVING NORTHEAST AT 40 MPH.

LOCALLY HEAVY RAIN...WIND GUSTS OF 50 TO 55 MPH...AND DIME SIZE HAIL
ARE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
HOPI POINT AT GRAND CANYON...PIMA POINT AT GRAND CANYON...HERMITS
REST...MARICOPA POINT AT GRAND CANYON AND PORTIONS OF THE HAVASUPAI
RESERVATION.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

LAT...LON 3595 11244 3604 11251 3623 11213 3612 11203
TIME...MOT...LOC 1757Z 240DEG 48KT 3605 11234

BAK

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1132 AM MST SUN AUG 30 2015

AZZ008-037-301845-
YAVAPAI COUNTY  MOUNTAINS-YAVAPAI COUNTY VALLEYS AND BASINS-
1132 AM MST SUN AUG 30 2015

...A STRONG THUNDERSTORM WILL AFFECT EASTERN YAVAPAI COUNTY...

AT 1131 AM MST...A STRONG THUNDERSTORM WAS OVER DEWEY-HUMBOLDT...OR
16 MILES SOUTHEAST OF CHINO VALLEY...MOVING NORTHEAST AT 10 MPH.

WINDS IN EXCESS OF 40 MPH AND HALF INCH HAIL ARE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
YAVAPAI COUNTY FAIRGROUNDS AND PRESCOTT VALLEY.

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 STATE ROUTE 89A BETWEEN MILE MARKERS 326 AND 327.
 STATE ROUTE 69 BETWEEN MILE MARKERS 282 AND 287.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 3451 11229 3453 11234 3467 11230 3460 11215
TIME...MOT...LOC 1831Z 211DEG 11KT 3456 11229

RR