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 312259
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
359 PM MST MON AUG 31 2015

.SYNOPSIS...STORM ACTIVITY IS EXPECTED TO SLOWLY MOVE EAST
THROUGH AT LEAST WEDNESDAY...WITH WESTERN YAVAPAI AND COCONINO
COUNTIES LIKELY DRYING OUT. AS EARLY AS THURSDAY...INCREASING
MOISTURE MAY LEAD TO BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS
LATE IN THE WORK WEEK.

&&

.DISCUSSION...IT HAS BEEN A CONVECTIVELY ACTIVE DAY ACROSS
MOST NORTHERN ARIZONA. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS DEVELOPED ACROSS THE REGION BY LATE MORNING.
SEVERAL STORMS PRODUCED VERY HEAVY RAINFALL AND THERE WAS ENOUGH
ENVIRONMENTAL SHEAR FOR A FEW ROTATING SUPERCELLS.

MOST MODEL GUIDANCE SUGGESTS SHOWER AND THUNDERSTORM ACTIVITY WILL
LARGELY DIMINISH THIS EVENING. THIS MAKES SENSE GIVEN THAT MOST
OF NORTHERN ARIZONA HAS ALREADY EXPERIENCED CONVECTIVE ACTIVITY.
THE EXCEPTION COULD BE IN SOUTHERN YAVAPAI COUNTY, BUT THERE
DOESN`T APPEAR TO BE ANY MESOSCALE MECHANISM IN PLACE AT THE
MOMENT TO GET ACTIVITY GOING THERE.

FOR TUESDAY AND WEDNESDAY...SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED TO DECREASE AS THE ATMOSPHERE DRIES A BIT...MOSTLY ACROSS
THE WESTERN PORTIONS OF NORTHERN ARIZONA. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED IN THE WHITE MOUNTAINS REGION WITH
ISOLATED OR NO ACTIVITY ELSEWHERE.

LONG RANGE GUIDANCE SUGGESTS ANOTHER SURGE OF MOISTURE WILL MOVE
INTO NORTHERN ARIZONA THURSDAY NIGHT INTO FRIDAY. SOUTHERLY WINDS
WILL INCREASE DURING THIS TIME PERIOD AS THE PRESSURE GRADIENT
STRENGTHENS BETWEEN A HIGH ACROSS EASTERN MEXICO/SOUTHERN TEXAS
AND A PACIFIC NORTHWEST TROUGH. THE GFS CONTINUES TO BE MORE
AGGRESSIVE THAN THE ECMWF WITH REGARDS TO THE AMOUNT OF MOISTURE
RETURN, SO TRENDS WILL HAVE TO BE MONITORED TO SEE WHICH SOLUTION
IS MORE LIKELY. STORMS THAT DO DEVELOP FRIDAY AFTERNOON MAY HAVE
MODEST SHEAR VALUES AND AT LEAST LIMITED CAPE TO WORK WITH, SO
SOME STRONG STORMS CANNOT BE RULED OUT.

AS WE HEAD INTO THE WEEKEND, BOTH THE GFS AND ECMWF ARE IN AGREEMENT
THAT A DRY WESTERLY FLOW WILL SPREAD ACROSS THE REGION GREATLY
REDUCING THE CHANCE FOR PRECIPITATION. THE BEST CHANCES FOR
AFTERNOON SHOWERS AND THUNDERSTORMS LOOK TO BE MOSTLY CONFINED TO
EASTERN ARIZONA SATURDAY AND SUNDAY.

&&

.AVIATION...FOR THE 00Z PACKAGE...SCT -TSRA WILL CONTINUE THIS
EVENING...BECOMING ISOLD AFT 05Z TUESDAY. LCL IFR CONDITIONS AND
GUSTY WINDS WITH THE STRONGER STORMS.  ISOLD TO SCT -TSRA WILL
DEVELOP OVER THE HIGHER TERRAIN AFT 17Z ON TUESDAY. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

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

&&

$$

PUBLIC...RR/CLM
AVIATION...BAK


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.