Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 261728
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1028 AM MST TUE AUG 26 2014

.SYNOPSIS...
SUBTROPICAL MOISTURE HAS MOVED NORTHWARD INTO SOUTHERN SECTIONS OF
THE STATE AND IS FORECAST TO MOVE INTO NORTHERN ARIZONA AHEAD OF AN
ADVANCING LOW PRESSURE TROUGH TODAY AND TONIGHT. THE PASSING TROUGH
WILL BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO THE STATE.
HEAVY RAIN AND FLOODING WILL BE THE MAIN THREAT...THOUGH SOME STRONG
THUNDERSTORMS WILL ALSO BE POSSIBLE. THURSDAY ONWARD THROUGH EARLY
NEXT WEEK...A DRY WEST TO NORTHWEST FLOW WILL BRING DRY CONDITIONS
AND SLIGHTLY WARMER HIGH TEMPERATURES.

&&

.UPDATE...
THE ONLY UPDATE MADE TO THE FORECAST THIS MORNING WAS TO ADD NORTH
CENTRAL AND NORTHEAST ARIZONA TO THE FLASH FLOOD WATCH. WE ARE
ALREADY SEEING STORM DEVELOPMENT IN EAST CENTRAL ARIZONA AND
EXPECT MORE WIDESPREAD ACTIVITY ACROSS THE NORTHEAST BY THIS
AFTERNOON AS THE LARGE SCALE LIFT FROM THE APPROACHING TROUGH ACTS
ON INCREASED MOISTURE (SATELLITE PW ESTIMATES SHOW THREE QUARTERS
OF AN INCH TO AN INCH IN THIS AREA ALREADY). ALL IN ALL...WE STILL
ANTICIPATE A VERY ACTIVE DAY OF CONVECTION ACROSS NORTHERN ARIZONA AIDED
BY SYNOPTIC SCALE LIFT FROM THE UPPER TROUGH. ENHANCED VERTICAL
WIND SHEAR ALSO ADDS A THREAT OF SOME STRONG STORMS. THIS THREAT
IS GREATEST THIS MORNING ACROSS NORTHWESTERN ARIZONA...SHIFTING
INTO NORTHEAST ARIZONA LATE THIS AFTERNOON THROUGH THIS EVENING.

&&

.DISCUSSION...
AN UPPER LOW AND TROUGH CONTINUES TO ADVANCE
EAST-SOUTHEAST ACROSS NEVADA EARLY THIS MORNING. AMPLE AMOUNTS OF
SUBTROPICAL MOISTURE HAVE MOVED NORTHWARD INTO THE SOUTHERN HALF OF
THE STATE. THE MOISTURE...INSTABILITY...MODERATE LARGE SCALE
SYNOPTIC LIFT...WEAK TO MODERATE OROGRAPHIC UP SLOPE FLOW WILL ALL
PLAY APART IN PRODUCING NUMEROUS SHOWERS AND THUNDERSTORMS TODAY
WITH THE THREAT OF HEAVY RAIN AND FLASH FLOODING FROM SOME OF THE
STRONGER STORMS. IN ADDITION TO THE HEAVY RAIN...THERE IS ENOUGH
SHEAR AND INSTABILITY THAT SOME OF THE STORMS MAY BECOME ORGANIZED
AND STRONG TO PRODUCE LARGE HAIL AND DAMAGING WINDS.

THE COLD FRONT ASSOCIATED WITH THE SYSTEM IS FORECAST TO MOVE
RAPIDLY EASTWARD ACROSS THE AREA EARLY WEDNESDAY MORNING AND INTO
NEW MEXICO BY LATE MORNING. THE COLD FRONT WILL PUSH THE DEEPER
MOISTURE INTO NEW MEXICO BRINGING AND END TO THE THREAT OF FLASH
FLOODING. THERE WILL STILL BE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS OVER NORTHERN ARIZONA WEDNESDAY AFTERNOON AND EARLY
EVENING. HIGH PRESSURE IS FORECAST TO BUILD OVER THE AREA WEDNESDAY
AFTERNOON AND BECOME ESTABLISHED OVER THE REGION LATE WEDNESDAY
NIGHT. A DRY NORTHWEST FLOW AND A MORE STABLE ATMOSPHERE WILL BRING
AND END TO THE SHOWERS AND THUNDERSTORMS OVERNIGHT WEDNESDAY INTO
EARLY THURSDAY MORNING.

THURSDAY INTO EARLY NEXT WEEK...DRY CONDITIONS AND SLIGHTLY WARMER
DAYTIME HIGHS ARE FORECAST THROUGH THIS PERIOD. A TROUGH OF LOW
PRESSURE WILL PASS BY TO THE NORTH OF ARIZONA SUNDAY INTO MONDAY
BRINGING A DRY BREEZY WESTERLY FLOW.

&&

.AVIATION...
FOR THE 18Z PACKAGE...SCATTERED TO NUMEROUS SHRA/TSRA
ACROSS NORTHERN ARIZONA TODAY AS A STRONG TROUGH ENHANCES STORM
ACTIVITY.  SCATTERED MVFR/WIDELY SCATTERED IFR CONDITIONS IN THE
HEAVIER SHOWERS. EXPECT STRONG ERRATIC GUSTY WINDS AND HAIL NEAR
STRONGER STORMS. STORM COVERAGE DECREASING AFTER 03Z-06Z...AND
MAINLY SHIFTING NE OF KFLG-KSOW LINE OVERNIGHT. AVIATION DISCUSSION
NOT UPDATED FOR AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ004>018-037>040.

&&

$$

PUBLIC.........MCS
AVIATION.......JJ

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF





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