Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 021005
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
305 AM MST SUN AUG 2 2015

.SYNOPSIS...EXPECT ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS ACROSS MOST OF NORTHERN ARIZONA TODAY. DRY AIR
WILL OVER TAKE THE REGION FROM MONDAY THROUGH WEDNESDAY LEADING
TO A BREAK IN STORM ACTIVITY. BEGINNING THURSDAY...MOISTURE WILL
INCREASE FROM THE SOUTH LEADING TO A RETURN OF DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS.

&&

.DISCUSSION...SHOWER ACTIVITY HAS GENERALLY DECREASED OVERNIGHT,
HOWEVER, A PASSING SHORTWAVE TROUGH CURRENTLY POSITIONED OVER
WESTERN COCONINO AND YAVAPAI COUNTY HAS KEPT ACTIVITY GOING ACROSS
PORTIONS OF NORTHERN ARIZONA THIS MORNING. WHILE THE GREATEST
COVERAGE HAS BEEN IN NAVAJO AND APACHE COUNTIES, A COUPLE
THUNDERSTORMS HAVE FORMED OVER SOUTHERN COCONINO AND NORTHERN
YAVAPAI COUNTIES. THIS IS LIKELY DUE TO FORCING FROM THE PASSING
SHORTWAVE TROUGH.

FOR TODAY, EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
ACROSS MUCH OF NORTHERN ARIZONA. GOOD LOW LEVEL MOISTURE EXISTS
ACROSS THE REGION, WITH OBSERVED DEW POINTS IN EXCESS OF 50 F.
NAM FORECAST SOUNDINGS SHOW GOOD SURFACE BASED INSTABILITY
DEVELOPING BY MID MORNING. GFS FORECAST SOUNDINGS FORECAST LESS
INSTABILITY, BUT STILL ENOUGH FOR CONVECTION. IN THE UPPER
LEVELS, THE PREVIOUSLY MENTIONED SHORTWAVE TROUGH PASSING FROM THE
SOUTHWEST TO NORTHEAST WILL HELP FOCUS CONVECTION. THIS SHOULD
KEEP SHOWER AND THUNDERSTORM ACTIVITY LASTING THE LONGEST IN
NORTHEASTERN ARIZONA.

STORM MOTION TODAY IS FORECAST TO BE FROM THE SOUTHWEST BETWEEN 5 TO
15 KNOTS. SO, THE BEST CHANCES FOR PRECIPITATION WILL BE ALONG
AND NORTHEAST OF THE MOGOLLON RIM, WITH THE LOWEST CHANCES FOR
PRECIPITATION IN THE LOW DESERTS OF YAVAPAI COUNTY. THE PRIMARY
THREAT FROM TODAY`S STORMS WILL BE FLOODING FROM HEAVY RAINFALL
AND FREQUENT LIGHTNING. HOWEVER, 1.0 INCH HAIL CANNOT BE RULED
OUT GIVEN THE PRESENCE OF AT LEAST MARGINAL INSTABILITY AND WEAK
LIFT ASSOCIATED WITH TODAY`S PASSING SHORTWAVE TROUGH.

MONDAY THROUGH WEDNESDAY...A DRY WESTERLY FLOW IS FORECAST TO
DEVELOP ACROSS NORTHERN ARIZONA SHARPLY REDUCING THE CHANCES FOR
SHOWERS AND THUNDERSTORMS. DAYTIME HIGH TEMPERATURES ARE FORECAST
TO BE NEAR TO A FEW DEGREES ABOVE NORMAL AT MOST PLACES.

FROM THURSDAY ONWARD...LONGER TERM MODEL GUIDANCE SUGGESTS THAT
LOW LEVEL MOISTURE MAY BE ON THE RISE AS A MOIST SOUTHERLY FLOW
DEVELOPS BETWEEN HIGH PRESSURE OVER NEW MEXICO AND A WEST COAST
TROUGH. THIS WOULD RESULT IN A RETURN OF DAILY CHANCES FOR SHOWERS
AND THUNDERSTORM ACROSS NORTHERN ARIZONA.

&&

.AVIATION...FOR THE 12Z PACKAGE...SCT SHRA/-TSRA WILL CONTINUE
THROUGH 13Z ACROSS PORTIONS OF SOUTHERN NAVAJO AND APACHE COUNTIES
AS WELL AS ACROSS PORTIONS OF COCONINO AND NORTHEASTERN YAVAPAI
COUNTIES. MOST ACTIVITY WILL DIMINISH AROUND SUNRISE. SCT
-SHRA/TSRA WILL DEVELOP AFTER 17Z THIS AFTERNOON CONTINUING THROUGH
04Z - 06Z MONDAY...WITH THE HIGHEST CONCENTRATION OF STORMS NORTH OF
I-40 AND EAST OVER NAVAJO AND APACHE COUNTIES. BRIEF MVFR/IFR
CONDITIONS WILL BE POSSIBLE IN THE HEAVIEST STORMS. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

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

&&

$$

PUBLIC...RR
AVIATION...CLM


FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF



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