Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000
FXUS65 KPSR 250300
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
800 PM MST THU JUL 24 2014

.SYNOPSIS...
STRONG HIGH PRESSURE WILL HOLD OVER THE FOUR CORNERS...RESULTING IN
SOME OF OUR WARMEST TEMPERATURES SO FAR THIS YEAR. SUFFICIENT
MONSOONAL MOISTURE WILL BE AROUND THE REGION TO SUPPORT AFTERNOON AND
EVENING STORM CHANCES THROUGH THE MIDDLE OF THE COMING WEEK...WITH
THE BEST FOCUS FOR STORMS LIKELY OVER THE HIGHER TERRAIN OF SOUTH-
CENTRAL ARIZONA. DAYTIME TEMPERATURES WILL STILL HOLD ABOVE SEASONAL
NORMALS...BUT SHOULD FALL BACK FROM NEAR-RECORD READINGS.

&&

.DISCUSSION...
FAIRLY QUIET NIGHT ACROSS THE AREA THIS AFTERNOON/EVENING...AS THE
ONLY AREA THAT SAW CONVECTION WAS LA PAZ AND YUMA COUNTIES. THERE
ARE STILL A FEW STORMS ACROSS PORTIONS OF LA PAZ COUNTY WHERE
MLCAPES ARE STILL HOVERING AROUND 500 J/KG...BUT THIS IS RAPIDLY
ERODING WITH THE LOSS OF DAYTIME HEATING. THE REST OF THE AREA
REMAINS VERY STABLE. TO THE EAST...A COUPLE OF OUTFLOWS ARE MAKING
THEIR WAY THROUGH THE PHOENIX AREA THIS EVENING BUT THERES NO
SUGGESTION OF SIGNIFICANT BLOWING DUST WITH ANY OF THEM. LOOKS TO BE
MORE OF A BRIEF WIND SHIFT THAN ANYTHING.

QUICK UPDATE TO ALLOW THE EXCESSIVE HEAT WARNING TO EXPIRE AT 8 PM
AS SCHEDULED. AFTER BACK TO BACK DAYS OF RECORD TYING OR RECORD
BREAKING TEMPERATURES FOR THE PHOENIX AND YUMA AREAS...SLIGHTLY
LOWER TEMPERATURES STILL LOOK ON TRACK FOR THE REGION FRIDAY THROUGH
THE WEEKEND. A LOOK AT THE AVAILABLE 00Z MODEL DATA SUGGESTS POPS
ARE IN GOOD SHAPE FOR THE REST OF THE NIGHT /A FEW ISOLATED SHOWERS
ALONG THE LOWER COLORADO RIVER VALLEY/. ASIDE FROM MINOR ADJUSTMENTS
TO TEMPS/DEWPOINTS BASED ON OBSERVED TRENDS...FORECAST IS IN GOOD
SHAPE.

&&

.PREVIOUS DISCUSSION...
THE DEEPEST MONSOON MOISTURE SURFACE HAS TRANSITIONED THROUGH CENTRAL
AZ THROUGH THE DAY AND HAS SETTLED OVER THE WESTERN THIRD OF AZ AND
ALONG THE CO RIVER VALLEY THIS AFTERNOON. MOSTLY CLEAR MORNING SKIES
ACROSS THE SOUTHEASTERN CORNER OF AZ ARE NOW DOTTED WITH SMALL
CU...INDICATING THE ANTICIPATED LOW AND MID LEVEL DRYING CONTINUES
AND STABILIZING OF THE ATMOSPHERE CONTINUES. SURFACE DEWPOINTS
INDICATE THE MOST FAVORABLE MONSOON MOISTURE BOUNDARY IS NOW ACROSS
WESTERN AZ...WHERE THERE ARE STILL SOME POCKETS OF 60 DEGREE
DEWPOINTS. IN ADDITION...SUBTLE UPPER LEVEL DYNAMICS IN THE FORM OF
AN UPPER JET STREAK ACROSS SOUTHERN NV AND CENTRAL UT WILL HELP FOCUS
ACTIVITY IN A LINE ALONG THE WESTERN FRINGES OF THE PHOENIX METRO
SOUTH TOWARDS GILA BEND AND TOWARDS THE CO RIVER VALLEY...INCLUDING
BLYTHE AND YUMA...FOR THE REST OF THE EVENING.

STILL ANTICIPATING SOMEWHAT COOLER TEMPERATURES FRIDAY AND INTO
SATURDAY AS THE UPPER HIGH...CURRENTLY TO OUR EAST OVER NM...WEAKENS
SLIGHTLY BY A DM OR TWO. IN ADDITION...LOW LEVEL MOISTURE VALUES WILL
LIKELY BE ON THE INCREASE AS SOME EXTENT OF GULF OF CALIFORNIA
MOISTURE WILL WORK ITS WAY INTO PORTIONS OF THE LOWER DESERT
ELEVATIONS. A STRONG OUTFLOW BOUNDARY FROM CONVECTION NEAR THE BAJA
TIP HAS BEEN OBSERVED ON SFC OBS AND SATELLITE DATA AND WILL CONTINUE
TO WORK NORTHWARD. BY FRIDAY AM...850MB DEWPOINTS COULD RETURN TO 10C
TO 12C AND EXPECT DEBRIS CLOUDS FROM TONIGHT`S ACTIVITY TO LINGER
LONGER INTO THE DAY. THIS INFUSION OF MOISTURE WILL SUPPORT AT LEAST
SLIGHT STORM CHANCES ACROSS MUCH OF THE FORECAST AREA FOR FRIDAY.

A BETTER THREAT FOR AFTERNOON AND EVENING CONVECTION
IS EXPECTED ON SATURDAY AS THE UPPER HIGH CENTER SHIFTS A LITTLE
FURTHER EAST...ALLOWING A DEEPER SOUTHEASTERLY FLOW TO DEVELOP OVER
THE REGION...IMPORTING MORE MOISTURE INTO THE DESERT SOUTHWEST.
ANOTHER WEAK SHORTWAVE EMBEDDED IN THIS FLOW APPEARS THAT IT WILL
MOVE INTO THE REGION...FURTHER ENHANCING THE CONVECTIVE ACTIVITY AS
MUCAPES ARE PUSHED UP INTO THE 500-1000 J/KG RANGE.

SUNDAY THROUGH THURSDAY...
IT APPEARS THAT A LOW-MID GRADE MONSOON
WILL LIKELY PREVAIL THROUGH THE EXTENDED PERIOD AS WEAK SOUTHERLY
FLOW ALOFT CONTINUES TO PULL MOISTURE INTO THE REGION...BUT WITH THE
UPPER HIGH CENTER ATTEMPTING TO REPOSITION ITSELF WESTWARD BACK OVER
THE REGION...STABILIZING THE AIRMASS SOMEWHAT AND PERHAPS PUTTING A
BIT OF A LID ON THE CONVECTIVE ACTIVITY.

&&

.CLIMATE...
RECORD HIGH TEMPERATURE FOR THE MIDDLE OF THE WEEK.

CITY        JULY 24             JULY 25
----        -------             -------
PHOENIX   116 IN 2014          115 IN 1943
YUMA      117 IN 2014/1943     120 IN 1943

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
GOING TO HAVE TO CONTEND WITH A FEW OUTFLOWS FOR THE REST OF THE
EVENING ACROSS THE METRO...BUT NOT LOOKING AT ANY NEW STORM
DEVELOPMENT. STORMS APPEAR MORE LIKELY ON FRIDAY BUT FOR NOW...WILL
KEEP ANY MENTION OUT OF THE TAFS UNTIL TIMING/COVERAGE CAN BE PINNED
DOWN.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A FEW SHOWERS REMAIN JUST TO THE EAST OF BLYTHE BUT THEY ARE QUICKLY
DISSIPATING AS OF 03Z. BOTH TERMINALS SHOULD REMAIN DRY FOR THE REST
OF THE NIGHT. ONLY SOME DEBRIS CLOUDS TO CONTEND WITH AT EITHER SE
CA TAF SITE.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
SLIGHTLY COOLER AFTERNOON TEMPERATURES ARE EXPECTED ALONG WITH
HIGHER HUMIDITY. MINIMUM RELATIVE HUMIDITY LEVELS WILL RANGE FROM 15
TO 25 PERCENT. A TYPICAL MONSOON DAILY THREAT OF AFTERNOON AND
EVENING THUNDERSTORMS ARE EXPECTED WITH THE HIGHEST PROBABILITIES IN
THE MOUNTAINS EAST OF PHOENIX. TYPICAL AFTERNOON AND EVENING
SOUTHWEST WINDS ARE EXPECTED WITH GOOD RECOVERY AT NIGHT.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...LEINS/NOLTE/PERCHA
AVIATION...LEINS
FIRE WEATHER...VASQUEZ





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