Severe Thunderstorm Warning 9, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1010 AM MST MON JUL 20 2009

.SYNOPSIS...STRONG HIGH PRESSURE AND MONSOON MOISTURE WILL REMAIN
ENTRENCHED OVER THE SOUTHWEST THROUGH THE COMING WEEK. THERE WILL BE
HIGHER CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY AS ADDITIONAL
MOISTURE HAS MOVED UP INTO NORTHERN ARIZONA.

&&

.DISCUSSION...MOISTURE LEVELS HAVE INCREASED THIS MORNING OVER THE
HIGH COUNTRY WITH SATELLITE IMAGERY SHOWING SIGNIFICANT CLOUD COVER
ACROSS MUCH OF THE NORTHLAND. THE 12Z SOUNDING SHOWED A 24 HOUR
INCREASE IN PRECIPITABLE WATER OF 0.30 COMPARED WITH YESTURDAY
MORNINGS SOUNDING. CHANCES FOR PRECIPITATION HAVE BEEN INCREASED
TODAY ACROSS NORTHERN ARIZONA AS THE ADDITIONAL MOISTURE SHOULD
PRODUCE MORE SHOWER AND THUNDERSTORM ACTIVITY. THUNDERSTORM MOTION
TODAY WILL BE PRIMARILY OUTFLOW DRIVEN WITH WEAK WESTERLY FLOW WHICH
COULD HELP TO PUSH SOME OF THE SHOWERS AND THUNDERSTORMS INTO THE
LITTLE COLORADO RIVER VALLEY THIS AFTERNOON.

FIRST PERIOD POP...WEATHER AND QPF GRIDS HAVE BEEN UPDATED THIS
MORNING.

&&

.PREV DISCUSSION 230 AM...

FOR TODAY...MOISTURE VALUES ACROSS THE AREA CONTINUE TO CREAK UPWARD
WITH THE CHANCE OF SHOWERS AND THUNDERSTORMS SLOWLY ON THE INCREASE.
THE HIGH CENTER WILL REMAIN OVER SOUTHERN ARIZONA PLACING A WEST TO
NORTHWEST FLOW ACROSS THE NORTHERN HALF OF ARIZONA. STORMS WILL
LIKELY FIRE OVER THE KAIBAB PLATEAU...MOGOLLON RIM AND WHITE
MOUNTAINS JUST BEFORE NOON AND THEN ATTEMPT TO MOVE EAST TO
SOUTHEASTWARD. THINK MOISTURE VALUES HAVE INCREASED SOME OVER
NORTHEAST ARIZONA AND A FEW STORMS WILL MAKE IT INTO THE LITTLE
COLORADO RIVER VALLEY DURING THE AFTERNOON. STORMS OVER THE WHITE
MOUNTAINS WILL EXPERIENCE MORE OF A PUSH SOUTHWARD. THE MAIN THREAT
FROM STORMS WILL BE LOCAL WIND GUSTS OF 35 TO 45 MPH AND HEAVY
DOWNPOURS OF UP TO TWO INCHES IN THE CORE OF THE STRONGER
STORMS...ESPECIALLY ALONG AND SOUTH OF THE MOGOLLON RIM. ISOLATED
SHOWER AND THUNDERSTORM ACTIVITY...ESPECIALLY OVER THE LOWER
ELEVATIONS...WILL LIKELY LAST WELL INTO THE NIGHT.

FOR TUESDAY AND THE REMAINDER OF THE WEEK...STRONG HIGH PRESSURE
WILL MOST LIKELY REMAIN CENTERED OVER THE SOUTHWEST UNITED
STATES. UNDER THIS PATTERN THERE SHOULD CONTINUE TO BE A BUILDUP OF
MONSOON MOISTURE WITH A GRADUAL INCREASE IN THE COVERAGE OF SHOWERS
AND THUNDERSTORMS THROUGH THE WEEK.

&&

AVIATION...FOR THE 18Z PACKAGE...EXPECT SCT SHRA/TSRA...MAINLY BTWN
20/20Z AND 21/04Z. MAINLY VFR CONDITIONS XCPT MVFR VSBYS PSBL IN THE
STRONGER STORMS...ALONG WITH LOCAL WIND GUSTS UP TO 35 KTS. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...TODAY AND TUESDAY...HIGH PRESSURE WILL REMAIN OVER
ARIZONA THIS WEEK. EXPECT SCATTERED MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS EACH DAY. SOME STORMS MAY LAST WELL INTO
THE NIGHT. DAILY HIGH TEMPERATURES WILL REMAIN ABOVE NORMAL. THE
WINDS WILL BE GENERALLY LIGHT...EXCEPT NEAR STORMS WHERE OUTFLOWS
COULD PRODUCE WIND GUSTS IN EXCESS OF 40 MPH.

WEDNESDAY THROUGH FRIDAY...HIGH PRESSURE WILL WEAKEN SLIGHTLY AND
SHIFT TOWARD THE 4-CORNERS. THIS SHOULD ALLOW FOR A GRADUAL INCREASE
IN MOISTURE AND THUNDERSTORM COVERAGE OVER NORTHERN AND CENTRAL
ARIZONA. WINDS WILL GENERALLY BE LIGHT OUTSIDE OF THUNDERSTORMS.

&&

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

&&

PUBLIC........................BOHLIN
AVIATION/FIRE WEATHER.........DB

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1018 AM MST MON JUL 20 2009

AZZ004>018-037>040-210645-
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-
1018 AM MST MON JUL 20 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
ARIZONA...NORTH CENTRAL ARIZONA...NORTHEAST ARIZONA AND WEST
CENTRAL ARIZONA.

.DAY ONE...TODAY AND TONIGHT

STRONG HIGH PRESSURE WILL CONTINUE TO BRING VERY WARM TEMPERATURES
AND SCATTERED THUNDERSTORMS TO NORTHERN ARIZONA. THUNDERSTORM
ACTIVITY THIS AFTERNOON WILL BE FAVORED ALONG THE MOGOLLON RIM AND
OVER THE WHITE MOUNTAINS. STORMS WILL GENERALLY BE OUTFLOW DRIVEN
TODAY WITH WEAK WESTERLY TO SOUTHWESTERLY FLOW HELPING TO PUSH
STORMS INTO THE LITTLE COLORADO RIVER VALLEY THIS AFTERNOON. THE PRIMARY
THREATS TODAY WILL BE FROM STRONG GUSTY WINDS NEAR THUNDERSTORMS...AND
LOCALLY HEAVY RAIN.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

STRONG HIGH PRESSURE WILL REMAIN CENTERED OVER THE SOUTHWEST
UNITED STATES...WITH MUCH WARMER THAN NORMAL DAYTIME TEMPERATURES
PERSISTING. GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
CONTINUE INTO THE WEEKEND.

.SPOTTER INFORMATION STATEMENT...

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