Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 100240
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
245 PM MST WED APR 9 2014

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL BRING MUCH ABOVE NORMAL
DAYTIME TEMPERATURES THROUGH FRIDAY. COOLER TEMPERATURES WILL THEN
OCCUR THIS WEEKEND AS A WEAK LOW PRESSURE SYSTEM MOVES ACROSS THE
AREA. A FEW SHOWERS MAY OCCUR ACROSS THE WHITE MOUNTAINS SATURDAY.
EXPECT DRY CONDITIONS WITH A WARMING TREND EARLY NEXT WEEK.

&&

.DISCUSSION...UPPER LEVEL RIDGE WILL CONTINUE TO BREAKDOWN OVER THE
NEXT 24 HOURS AS A SHORTWAVE TROUGH COMES ONSHORE. THIS WILL ALLOW
FOR UPPER LEVEL MOISTURE TO CONTINUE TO STREAM INTO THE
REGION...KEEPING PARTLY TO MOSTLY CLOUDY CONDITIONS IN PLACE.
CURRENT FORECAST ON TRACK SO NO UPDATES EXPECTED AT THIS TIME. SEE
PREV DISCUSSION BELOW FOR FURTHER FORECAST DETAILS.

&&

.AVIATION...VALID THRU 11/06Z.
UPPER LEVEL HIGH PRESSURE WILL REMAIN OVER SE AZ THRU THURSDAY WITH
HIGH LEVEL MOISTURE STREAMING ACROSS THE REGION. THIS PATTERN WILL
YIELD MOSTLY SCT CLOUDS ABOVE 20K FT AGL...AND SURFACE WIND WILL BE
MAINLY LESS THAN 10 KTS THRU THURSDAY MORNING. SURFACE WIND THURSDAY
WILL BECOME WLY/SWLY 10-15 KTS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.

&&

.FIRE WEATHER...THE HOT AND VERY DRY AIR MASS OVER THE REGION WILL
REMAIN IN PLACE THROUGH FRIDAY. HUMIDITY RECOVERIES TONIGHT AND
THURSDAY NIGHT WILL BE VERY POOR WITH DAYTIME MINIMUM RELATIVE
HUMIDITIES DROPPING INTO THE SINGLE DIGITS EACH AFTERNOON. SOME
AREAS WILL DROP BELOW 5 PERCENT FOR EXTENDED PERIODS OF TIME EACH
AFTERNOON AND EVENING. WINDS WILL BE LIGHT AND TERRAIN DRIVEN
THROUGH THURSDAY MORNING THEN BECOME SOUTHWEST 10-15 MPH THURSDAY
AFTERNOON.

AN UPPER LEVEL LOW WILL APPROACH THE REGION LATE FRIDAY AND MOVE
EAST ACROSS SOUTHERN AZ SATURDAY INTO SATURDAY NIGHT. THIS SYSTEM
WILL BRING BREEZY SW WINDS SATURDAY AFTERNOON...WITH POSSIBLE RED
FLAG CONDITIONS OVER THE SE PART OF THE AREA LATER THAT AFTERNOON
INTO THE EVENING HOURS. BEYOND THAT...DRY AND WARMER THAN NORMAL
CONDITIONS ARE EXPECTED WITH OCCASIONAL BREEZINESS INTO NEXT WEEK.

&&

.PREV DISCUSSION/ISSUED AT 245 PM MST/...UPPER LEVEL RIDGE AXIS OVER
THE SWRN CONUS WITH LOW PRESSURE CENTERED WELL OFF THE CALIFORNIA
COAST. FAIRLY THICK SCATTERED TO BROKEN CIRRIFORM CLOUDS WERE MOVING
EWD ACROSS SE AZ. EXPECT PARTLY CLOUDY SKIES THUR FOLLOWED BY PARTLY
CLOUDY TO MOSTLY CLOUDY SKIES THUR NIGHT-FRI AS THE EASTERN PACIFIC
LOW PRESSURE SYSTEM MOVES EWD TOWARD THE SOUTHERN CALIFORNIA COAST.
MEANWHILE...A VERY DRY SURFACE REGIME WILL PREVAIL INTO FRI.

WEAK UPPER LOW CENTERED NEAR THE SRN CALIFORNIA COAST FRI NIGHT WILL
WEAKEN AND MOVE EWD ACROSS ARIZONA AS A POSITIVE-TILT OPEN WAVE
SYSTEM SAT AND SAT NIGHT. HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS
ACROSS THE WHITE MOUNTAINS SAT AND SAT NIGHT...BUT DRY CONDITIONS
SHOULD CONTINUE ELSEWHERE. GIVEN COOLING ALOFT AND THE AVAILABLE
MID-LEVEL MOISTURE...THERE SHOULD BE AT LEAST SOME VIRGA SAT.

UPPER RIDGE AXIS ADJACENT THE WEST COAST WILL PROVIDE A DRY NWLY
FLOW ALOFT REGIME SUN. THE UPPER RIDGE AXIS WILL MOVE EWD INTO THE
SWRN CONUS MON...THEN THE RIDGE AXIS IS PROGGED TO FLATTEN TUE.
THEREAFTER...09/12Z ECMWF WAS MARKEDLY MORE-AMPLIFIED WITH THE NEXT
SHORTWAVE TROUGH OVER SRN CALIFORNIA WED VERSUS THE GFS. AT THIS
TIME APPEARS THAT THE BULK OF MOISTURE ASSOCIATED WITH THIS SYSTEM
WILL BE ABOVE 500 MB. THUS...EXPECT CONTINUED PRECIP-FREE CONDITIONS
WED UNDER PARTLY CLOUDY SKIES.

QUITE WARM DAYTIME TEMPS WILL PREVAIL THUR-FRI FOLLOWED BY A COOLING
TREND THIS WEEKEND. DAYTIME TEMPS SUN WILL BE CLOSE TO SEASONAL
NORMALS. EXPECT WARMER TEMPS NEXT TUE...THEN DAYTIME TEMPS TO LOWER
AGAIN TO NEAR SEASONAL AVERAGES WED.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON

DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA








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