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000
FXUS65 KTWC 182105
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
205 PM MST FRI APR 18 2014

.SYNOPSIS...A PACIFIC LOW PRESSURE SYSTEM WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND...WITH THE BEST CHANCE
FOR MEASURABLE RAIN AND A FEW LIGHTNING STRIKES OCCURRING SATURDAY.
AFTER SEASONAL TEMPERATURES AGAIN SATURDAY...A WARMING TREND WILL
BEGIN SUNDAY AND CONTINUE INTO THE FIRST PART OF THE NEW WORK WEEK.

&&

.DISCUSSION...MOISTURE CONTINUES TO MOVE NE ACROSS SE AZ AHEAD OF
UPPER LOW NEARING THE NRN BAJA COAST. HAVE BEEN A FEW LIGHTNING
STRIKES AND WIND GUSTS ASSOCIATED WITH VERY LIGHT RAIN. A FEW
HUNDREDTHS OF AN INCH WAS RECORDED EAST OF SAINT DAVID. HAVE ALSO
HAD REPORTS OF ISOLD BLOWING DUST NW OF TUCSON NEAR I-10.

EXPECT CHANCES FOR SHOWER AND TSTM ACTIVITY TO CONTINUE OVERNIGHT
ALTHOUGH THUNDER CHANCES SHOULD SUBSIDE WITH THE LOSS OF DAYTIME
HEATING. AS UPPER LOW DRAWS NEAR...THE BEST CHANCE FOR THUNDERSTORMS
TO OCCUR IS LIKELY TO BE SATURDAY AFTN/EVE. OVERALL...DO NOT EXPECT
SIGNIFICANT RAIN AMOUNTS BUT SOME LOCATIONS MIGHT SQUEEZE OUT A
QUARTER OF AN INCH OR SO.  SHOWERS COULD LINGER OR REDEVELOP SUNDAY
AFTERNOON NEAR THE NM BORDER ON THE BACK SIDE OF THE UPPER LOW.

TEMPERATURES WILL BEGIN TO WARM BACK UP SUNDAY AND PEAK MONDAY AND
TUESDAY UNDER A RIDGE OF HIGH PRESSURE. A TROUGH CROSSING THE
NRN/CENTRAL ROCKIES TUE-WED WILL BRING GUSTY WINDS TO SE AZ BOTH
DAYS. TEMPERATURES WILL DROP OFF SLIGHTLY AS THE TROUGH PASSES...BUT
ABOVE NORMAL READINGS WILL PREVAIL FOR THE LATTER HALF OF NEXT WEEK.

&&

.AVIATION...VALID THRU 20/00Z.
UPPER LEVEL LOW PRESSURE OVER SOUTHERN CALIFORNIA WILL MOVE ACROSS
SOUTHERN ARIZONA TONIGHT AND SATURDAY...PRODUCING OVERCAST CLOUD
DECKS MOSTLY ABOVE 12K FT AND ISOLD TO SCT -SHRA. AN ISOLD -TSRA NOT
OUT OF THE QUESTION EARLY THIS EVENING THROUGH 19/02Z. WINDS GUSTS
AROUND 30 KTS NEAR THESE SHOWERS. CHANCES FOR -SHRA/-TSRA ARE BETTER
ON SATURDAY AFTERNOON WITH GUSTS NEAR 35KTS. MID AND UPPER LEVEL
CLOUD DECKS NOT FULLY CLEARING OUT UNTIL THE LOW MOVES FURTHER EAST
ON SUNDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A WEAK UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE
ACROSS SOUTHERN ARIZONA TONIGHT THROUGH EARLY SUNDAY. ENOUGH
MOISTURE IS PRESENT WITH THIS SYSTEM FOR ISOLATED TO SCATTERED
SHOWERS THROUGH SATURDAY. THE ATMOSPHERE IS UNSTABLE ENOUGH TO
SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS EARLY THIS EVENING AND ON
SATURDAY. RAINFALL AMOUNTS ARE EXPECTED TO BE RATHER LIGHT FOR
VALLEY AND DESERT LOCATIONS. MOUNTAIN PRECIPITATION GENERALLY A
QUARTER INCH OR LESS. THE MAIN CONCERN WILL BE THE POTENTIAL FOR
GUSTY AND ERRATIC WINDS ASSOCIATED WITH THE SHOWERS AND
THUNDERSTORMS. A FEW SHOWERS COULD LINGER NEAR THE NEW MEXICO BORDER
ON SUNDAY WITH A RETURN TO DRY CONDITIONS EARLY NEXT WEEK.

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

&&

$$

DROZD/SAMPSON

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