Area Forecast Discussion
Issued by NWS Phoenix, AZ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 KPSR 230352
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
850 PM MST FRI AUG 22 2014

.SYNOPSIS...
MUCH DRIER CONDITIONS ARE EXPECTED THROUGH THE WEEKEND ALONG WITH
SLIGHTLY COOLER THAN NORMAL TEMPERATURES. A RETURN TO A MORE TYPICAL
MONSOON PATTERN IS EXPECTED EARLY NEXT WEEK...WITH AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION.

&&

.DISCUSSION...
THE COLD CORE UPPER LOW THAT SUPPORTED THE MASS OF CONVECTION LAST
EVENING HAS NOW PROPAGATED INTO SWRN COLORADO...LEAVING DRY
SUBSIDENT NWLY FLOW SPLAYED ACROSS THE FORECAST AREA. DIURNALLY
FORCED CU HAVE LARGELY DISSAPTED RESULTING IN A DELIGHTFULLY CLEAR
AND DRY LATE AUGUST EVENING. MADE SOME MINOR CHANGES REDUCING CLOUD
GRIDS...AS WELL AS ACCOUNTING FOR SHORT TERM TEMPERATURE TRENDS.
NEVERTHELESS...THE BULK OF THE FORECAST WAS LEFT UNCHANGED CALLING
FOR CONTINUED SLIGHTLY COOLER THAN AVERAGE TEMPERATURES DESPITE
MOSTLY CLEAR SKIES.

&&

.PREVIOUS DISCUSSION...
/226 PM MST FRI AUG 22 2014/
DRIER WEST-NORTHWESTERLY FLOW ALOFT WILL CONTINUE TO SET UP ACROSS
THE REGION BEHIND THE DEPARTING TROUGH THIS EVENING...AND THIS WILL
EFFECTIVELY SHUNT MONSOON MOISTURE EASTWARD INTO NEW MEXICO FOR THE
WEEKEND. HOLISTICALLY...THE SAME DRIER/STABLE PATTERN IS EXPECTED
FOR SATURDAY AND SUNDAY AS LOW LEVEL MIXING RATIOS BOTTOM OUT AROUND
5-6 G/KG. DAYTIME TEMPERATURES WILL CONTINUE TO BE BELOW NORMAL FOR
ANOTHER A COUPLE OF DAYS...HOLDING IN THE MID TO UPPER 90S TO AROUND
100 DEGREES SATURDAY...WITH A FEW MORE DEGREES OF WARMING FOR SUNDAY.

NEXT WEEK WILL SEE A RETURN TO A MORE TYPICAL MONSOON SETUP AS HIGH
PRESSURE SLIDES EAST AND LOW LEVEL WINDS TURN AROUND OUT OF THE
SOUTHEAST. WHILE THERE ARE SOME DIFFERENCES IN THE MODELS REGARDING
A TROUGH MOVING THROUGH UTAH BY THE MIDDLE OF NEXT WEEK...BOTH THE
GFS AND EUROPEAN...AS WELL AS THE 12Z NAEFS INDICATE A NOTEWORTHY
INCREASE IN MOISTURE ACROSS THE AREA MONDAY/TUESDAY NEXT WEEK. THIS
COULD BE THE RESULT OF THE PASSAGE OF A TROPICAL SYSTEM WELL SOUTH
OF THE GULF OF CALIFORNIA...OR IT COULD SIMPLY BE OUTFLOW DRIVEN
FROM CONVECTION OVER SONORA. REGARDLESS...MIXING RATIOS EXPECTED TO
RETURN TO THE 10-12 G/KG RANGE EARLY NEXT WEEK WHICH SHOULD SET THE
STAGE FOR AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY THROUGH AT
LEAST FRIDAY. TOUGH TO PICK OUT ONE ACTIVE DAY OVER ANOTHER...BUT
POPS HAVE BEEN NUDGED TOWARD CLIMO /AND SLIGHTLY HIGHER EAST OF
PHOENIX/ FROM TUESDAY THROUGH FRIDAY.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA
INCLUDING KPHX...KIWA...KSDL...KIPL...AND KBLH...

MOSTLY CLEAR SKIES WILL PREVAIL THROUGH SATURDAY AFTERNOON WITH ANY
TSTM ACTIVITY WELL REMOVED EAST INTO NEW MEXICO. WITH NO WEATHER IN
THE AREA AND A WEAK PRESSURE GRADIENT...SFC WINDS WILL REMAIN RATHER
LIGHT AND FOLLOW THE TYPICAL DAILY TRENDS. FORECAST CONFIDENCE IS
HIGH.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
HUMIDITIES WILL GRADUALLY TREND UP EARLY IN THE WEEK...STAYING
ELEVATED AS THE WEEK PROGRESSES WITH GOOD OVERNIGHT RECOVERY. STORM
CHANCES WILL REMAIN SLIGHT AND FAVOR THE HIGHER TERRAIN OF SOUTH
CENTRAL ARIZONA...HOWEVER THEY WILL EXPAND SLOWLY WESTWARD TO NEAR
THE LOWER COLORADO RIVER VALLEY BY WEDNESDAY. HAINES INDEX VALUES
PEAK AT 5 OVER PORTIONS OF SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA MONDAY BEFORE TRENDING DOWNWARD. EXPECT LOWER VALUES OVER
SOUTH-CENTRAL ARIZONA DUE TO BETTER ATMOSPHERIC MOISTURE CONTENT.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...MO/MEYERS/LEINS
AVIATION...MO
FIRE WEATHER...AJ





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