Area Forecast Discussion
Issued by NWS Flagstaff, AZ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KFGZ 260446
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
944 PM MST MON AUG 25 2014

.SYNOPSIS...
SUBTROPICAL MOISTURE WILL MOVE NORTHWARD OVER NORTHERN
ARIZONA TONIGHT AHEAD OF AN ADVANCING LOW PRESSURE TROUGH WITH
INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS. THE PASSING
TROUGH WILL BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO THE STATE
ON TUESDAY. HEAVY RAIN AND FLOODING WILL BE THE MAIN
THREATS...THOUGH SOME STRONG THUNDERSTORMS WILL ALSO BE
POSSIBLE. THURSDAY ONWARD...A DRYING NORTHWEST FLOW WILL DECREASE
THUNDERSTORM CHANCES.

&&
.DISCUSSION...ISOLATED THUNDERSTORMS HAVE BEEN MOVING FROM SOUTHWEST
TO NORTHEAST IN SOUTHERN YAVAPAI AND APACHE COUNTIES THIS EVENING.
ONE STORM DROPPED OVER TWO INCHES OF RAIN ALONG THE SOUTHERN BORDER
OF YAVAPAI COUNTY AND MARICOPA COUNTY NEAR HIGHWAY 93. MORE SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER WESTERN COCONINO AND
SOUTHERN YAVAPAI COUNTY TONIGHT AS THE TROUGH OF LOW PRESSURE OVER
CALIFORNIA AND NEVADA GETS CLOSER TO ARIZONA AND PROVIDES MORE
LIFT. CURRENT FORECAST SHOWS THIS INCREASE OVERNIGHT. MAY UPDATE
FORECAST LATER THIS EVENING TO ADJUST TIMING OF PRECIPITATION.
OTHERWISE...NO CHANGES EXPECTED.

&&

.PREV DISCUSSION /344 PM MST/...AN INCREASE IN MOISTURE IS EVIDENCED
THIS AFTERNOON MAINLY SOUTH OF I-40 WHERE A COUPLE OF AREAS OF
SCATTERED STORMS HAVE DEVELOPED. THE STRONGER STORMS SO FAR HAVE
DEVELOPED IN WESTERN YAVAPAI COUNTY WHERE MOISTURE AND INSTABILITY
ARE HIGHEST. WEAKER STORMS HAVE DEVELOPED OVER THE WHITE MOUNTAINS.
A CHANCE FOR SHOWERS WILL CONTINUE THIS EVENING FOR MOST OF NORTHERN
ARIZONA BUT DON`T EXPECT WIDESPREAD ACTIVITY UNTIL MUCH LATER
TONIGHT OR EARLY TUESDAY MORNING.

THE APPROACHING LOW PRESSURE SYSTEM HAS MOVED INTO NORTHERN
NEVADA AND WILL CONTINUE PUSHING SOUTH OVER THE NEXT 24 HRS. WE
ARE STILL ANTICIPATING A WIDESPREAD PRECIPITATION EVENT TO UNFOLD
AS BROAD SYNOPTIC SCALE LIFT FROM THE TROUGH INTERACTS WITH PLENTY
OF MONSOON MOISTURE STREAMING NORTH ACROSS THE FORECAST AREA.
THERE APPEAR TO BE TWO FEATURES AT PLAY HERE...THE APPROACHING
TROUGH FROM THE NORTHWEST PROVIDING SYNOPTIC SCALE LIFT...AND A
WEAKER DISTURBANCE ROTATING NORTH INTO THE WHITE MOUNTAINS FROM
SOUTHERN ARIZONA. BELIEVE THE BEST THREAT FOR HEAVY RAIN AND
FLOODING WILL BE WHERE THESE FEATURES INTERACT WITH THE DEEPEST
MOISTURE CONTENT...ROUGHLY OVER WESTERN AND SOUTHERN PORTIONS OF
OUR FORECAST AREA WHERE A FLASH FLOOD WATCH IS IN EFFECT THROUGH
TUESDAY EVENING. A GENERAL 1-2 INCHES OF RAINFALL ARE ANTICIPATED
WITH LOCALLY HIGHER AMOUNTS...ESPECIALLY IN UP-SLOPE FAVORED AREAS
AND UNDER THE STRONGEST STORM CELLS.

IN ADDITION...INCREASED SHEAR AND INSTABILITY ASSOCIATED WITH THE
TROUGH WILL BRING A THREAT FOR STRONG OR ORGANIZED STORMS THAT
COULD PRODUCE HAIL AND HIGH WINDS.

ACTIVITY WILL BEGIN TO DECREASE BY WEDNESDAY MORNING AS THE TROUGH
MOVES INTO COLORADO. SCATTERED STORMS WILLS TILL BE POSSIBLE
WEDNESDAY WITH COOL AIR ALOFT AND AVAILABLE MOISTURE...BUT A QUICK
DRYING TREND MOVES IN BY THURSDAY WITH VERY LITTLE CHANCE FOR ANY
PRECIPITATION THURSDAY INTO NEXT WEEKEND.

&&

.AVIATION...
FOR THE 06Z PACKAGE...ISOLD TSRA SOUTH OF A KPRC-KSJN LINE THROUGH
10Z. SHRA/TSRA COVERAGE INCREASING FROM SOUTH TO NORTH AFTER 10Z AND
CONTINUING THROUGH TUESDAY AFTERNOON. AREAS MVFR/LOCAL IFR
CONDITIONS IN THE HEAVIER RAIN AREAS. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY EVENING
FOR AZZ004>008-015>018-037-038.

&&

$$

PUBLIC.........MAS/MCS
AVIATION.......MAS

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.