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443
FXUS65 KPSR 200320
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
815 PM MST SAT APR 19 2014

.SYNOPSIS...
HIGH PRESSURE ALOFT WILL BUILD INTO THE AREA SUNDAY INTO EARLY NEXT
WEEK...AND LEAD TO SUNNY DAYS AND CLEAR NIGHTS ALONG WITH SHARPLY
WARMING HIGH TEMPERATURES. BREEZY TO WINDY CONDITIONS ARE EXPECTED
NEXT TUESDAY INTO WEDNESDAY AS A DRY WEATHER SYSTEM PASSES BY TO OUR
NORTH. THE PASSING SYSTEM WILL LEAD TO COOLER WEATHER...WITH HIGH
TEMPERATURES FALLING TO NEAR SEASONAL NORMALS ON WEDNESDAY. HIGHER
PRESSURE WILL RETURN FOR THE LATTER PART OF THE NEXT WORK WEEK...
BRINGING ANOTHER WARMING TREND AND GENERALLY SUNNY SKIES.

&&

.DISCUSSION...
THE PACIFIC LOW PRESSURE SYSTEM CONTINUED TO SLOWLY TRACK EAST
THROUGH CENTRAL AND EASTERN AZ THIS EVENING...AND SHOULD BE IN
CENTRAL NEW MEXICO BY SUNDAY MORNING. UNFORTUNATELY FOR A LARGE PART
OF SOUTHWEST AND SOUTH CENTRAL AZ...INCLUDING PHOENIX...UPPER LEVEL
CONVERGENCE/SUBSIDENCE WITH THE BACKSIDE OF THE TROF MOVED INTO THE
AREA A LITTLE FASTER AND PREVENTED SHWR/TSTM DEVELOPMENT. AS PER
AFTERNOON SATELLITE IMAGERY...MOST UPPER LEVEL STORM SUPPORT WAS
FOCUSED OVER THE SOUTHEAST QUARTER OF AZ...INCLUDING PARTS OF OUR
ZONE 24 SOUTHERN GILA COUNTY.

AS THE LOW PRESSURE SYSTEM CONTINUES TO MOVE EAST THIS EVENING...
ONLY A SLIGHT CHANCE OF SHWRS/TSTMS WILL REMAIN OVER OUR MOUNTAINOUS
SOUTHERN GILA COUNTY ZONE 24 THROUGH MIDNIGHT. OTHERWISE CLEARING
SKIES ARE EXPECTED OVER THE REMAINDER OF THE FORECAST AREA...
SOUTHEAST CA TO SOUTH CENTRAL AZ. FORECASTS WERE UPDATED TO REMOVE
ANY SHWR THREATS THE REMAINDER OF THE EVENING...EXCEPT FOR SOUTHERN
GILA COUNTY ZONE 24. THE SLIGHT CHANCE OF SHOWERS FORECAST FOR A
SMALL PART OF EASTERN SOUTHERN GILA COUNTY ON SUNDAY WAS ALSO
REMOVED AS STRONG SUBSIDENCE WITH THE BUILDING SHORTWAVE RIDGE WILL
PRECLUDE ANY SHOWER POSSIBILITIES.

OTHERWISE CURRENT FORECASTS LOOK OK THROUGH MONDAY. NO FURTHER
UPDATES.


.PORTIONS OF PREVIOUS DISCUSSION...210 PM MST...
UPPER LEVEL PACIFIC LOW CONTINUED TO PUSH EASTWARD ACROSS THE DESERT
SOUTHWEST EARLY THIS AFTERNOON WITH THE MAIN LOW CENTER SHIFTED INTO
FAR SOUTH CENTRAL ARIZONA. MOST OF THE DYNAMICS/Q FORCING HAS
SHIFTED INTO FAR EASTERN OR SOUTHEAST ARIZONA...TO THE SOUTHEAST OF
OUR CWA...AND THE ASSOCIATED CONVECTION HAS SHIFTED SOUTHEAST OF OUR
AREA AS WELL. ONE OF THE MAIN VORT MAXES ROTATING THRU THE BASE OF
THE TROF...AND CLEARLY SEEN IN THE VAPOR IMAGERY...WAS TREKKING
ALONG THE SRN AZ/MEXICAN BORDER EARLY THIS EVENING...AND THE PVA
INDUCED CONVECTION AHEAD OF IT WAS PUSHING THRU FAR SERN AZ...WELL
SOUTHEAST OF THE GREATER PHOENIX AREA.

OTHERWISE...IR IMAGERY INDICATED PARTLY CLOUDY SKIES ACROSS MUCH OF
THE THE CWA...AS THE COLD AIR ALOFT MOVING OVER THE DESERTS HELPED
GENERATE VARIABLE AMOUNTS OF CU.  THE LOW PRESSURE SYSTEM WILL
CONTINUE TO SHIFT EAST ALLOWING FOR DRIER AND MORE SUBSIDENT AIR TO
OVERSPREAD THE LOWER DESERTS. THERE WILL BE A LINGERING SLIGHT
CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE HIGHER TERRAIN MAINLY
EAST OF GLOBE UNTIL MIDNIGHT...AND SKIES ACROSS MOST OF THE CWA WILL
BECOME MOSTLY CLEAR.

FOR SUNDAY...TROF AXIS WILL SHIFT INTO NEW MEXICO...AND HIGH
PRESSURE ALOFT WILL BUILD INTO THE DESERTS FROM THE WEST. THERE WILL
BE A BIT OF LINGERING MOISTURE FOR PARTLY CLOUDY SKIES OVER THE
HIGHER TERRAIN EAST OF PHOENIX. OTHERWISE EXPECT MOSTLY SUNNY SKIES
ALONG WITH WARMING HIGH TEMPERATURES. HIGH TEMPS WILL RISE SEVERAL
DEGREES AND INTO THE LOW TO MID 90S ACROSS THE WARMEST LOWER
DESERTS. HIGH PRESSURE ALOFT WILL BUILD FURTHER ON MONDAY...LEADING
TO SOME ADDITIONAL WARMING UNDER GENERALLY SUNNY SKIES.

FOR TUESDAY INTO WEDNESDAY...BOTH THE GFS AND ECMWF CONTINUE TO CALL
FOR A RATHER VIGOROUS PACIFIC UPPER TROF TO MOVE EAST THROUGH THE
DESERT SOUTHWEST...BRINGING CONSIDERABLE WIND TO THE AREA TUESDAY
AFTERNOON AND EVENING...AND LEADING TO SOME CONCERNS REGARDING
POTENTIAL FOR DANGEROUS FIRE WEATHER CONDITIONS. TOO EARLY AT THIS
TIME TO ISSUE A FIRE WEATHER WATCH...BUT THIS MAY BE NEEDED SOMETIME
IN THE NEXT DAY OR SO SHOULD CONFIDENCE IN THE EVENT CONTINUE TO
CLIMB. OTHERWISE THIS WILL BE A TYPICAL APRIL SYSTEM FOR OUR
CWA...BRINGING WIND AND COOLING AND NO PRECIP. IT APPEARS TO BE A
VERY DRY SYSTEM AND SKIES SHOULD BE MOSTLY SUNNY FOR THE MOST PART
BOTH DAYS. DESPITE THE WIND POTENTIAL...THIS TROF WILL LIKELY PASS
TO FAR TO OUR NORTH TO BRING SIGNIFICANT COOLING...AND HIGH TEMPS
ARE FORECAST TO DROP BACK TO NEAR SEASONAL NORMALS ON
WEDNESDAY...WITH THE WARMER DESERTS FALLING INTO THE MID TO UPPER
80S. FLAT UPPER RIDGING...AND DRY WESTERLY FLOW ALOFT...WILL FOLLOW
ON THURSDAY FOR MOSTLY SUNNY SKIES AND A BIT OF WARMING WITH THE
WARMER DESERTS CLIMBING BACK INTO THE LOWER 90S.

OPERATIONAL AND ENSEMBLE MODEL SPREAD IS SOMEWHAT HIGHER THAN SEEN
RECENTLY FOR THE END OF NEXT WEEK...HOWEVER STILL REMAINS RELATIVELY
SMALL IN A SEASONAL SENSE. FLAT RIDGING AND/OR QUASI-ZONAL FLOW
SHOULD PREDOMINATE THE GENERAL PATTERN FOR THE MAJORITY OF TIME WITH
H5 HEIGHTS HOVERING NOT FAR FROM 576DM. THIS MODEL AVERAGE SOLUTION
FOR HEIGHTS ALOFT IS SLIGHTLY HIGHER THAN PREVIOUS MODEL
ITERATIONS...AND CONSEQUENTLY HAVE EDGED FORECAST HIGHS SLIGHTLY
WARMER TO JUST ABOVE CLIMATOLOGICAL LEVELS. THERE IS STILL NO
EVIDENCE SUPPORTING ANY PRECIPITATION MUCH OF NEXT WEEK...WITH ONLY
VERY LIMITED OPPORTUNITY POSSIBLY ARRIVING NEXT WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
THROUGH 03Z SUN...SCT-BKN CLOUDS AOA 12 THSD AGL. LIGHT AND VARIABLE
WIND UNDER 8 KNOTS. FROM 03Z SUN TO 19Z SUN...FEW CLDS NEAR 16 THSD
MSL. LIGHT AND VRBL WIND UNDER 7 KNOTS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THROUGH 19Z SUN...FEW CLDS BASED NEAR 16 THSD AGL. LIGHT SOUTH TO
SOUTHWEST WIND UNDER 7 KNOTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
WESTERLY FLOW ALOFT WILL BRING WARM AND DRY CONDITIONS FOR TUESDAY
WITH WELL ABOVE SEASONAL NORMAL HIGH TEMPERATURES. A COOLING TREND
ENSUES WEDNESDAY AND THURSDAY AS A LOW PRESSURE SYSTEM MOVES INTO
THE GREAT BASIN AND THE PACIFIC NORTHWEST. THE BIGGEST IMPACT WITH
THIS SYSTEM WILL BE AN INCREASE IN WIND AREA-WIDE TUESDAY INTO
WEDNESDAY...WITH GUSTS UP TO 35 MPH POSSIBLE...AND EVEN STRONGER
GUSTS EXPECTED ACROSS SOUTHEAST CALIFORNIA AND PORTIONS OF THE LOWER
COLORADO RIVER VALLEY. MINIMUM HUMIDITY LEVELS ALSO BOTTOM OUT IN
THE SINGLE DIGITS DURING THIS TIME FRAME OF STRONG
WINDS...PRESENTING AN INCREASED FIRE DANGER THREAT AND THE POSSIBLE
ISSUANCE OF RED FLAG WARNINGS IN SOME AREAS. LIGHT WINDS...WITH DRY
AND WARMER CONDITIONS ARE ON TAP THURSDAY THROUGH SATURDAY AS
HIGH PRESSURE ALOFT BUILDS BACK INTO THE AREA.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...VASQUEZ/CB/MO
AVIATION...VASQUEZ
FIRE WEATHER...MEYERS/KUHLMAN



















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