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 252244
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
344 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...
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 00Z PACKAGE...SCATTERED TSRA WEST OF KGCN-KPRC
LINE THROUGH 02-04Z WITH ISOLD SHOWERS ELSEWHERE. SHRA/TSRA COVERAGE
INCREASING FROM SOUTH TO NORTH AFTER 08-12Z 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.........MCS
AVIATION.......JJ

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.