Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 252243
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
340 PM MST THU DEC 25 2014

.SYNOPSIS...EXPECT BREEZY TO WINDY CONDITIONS EARLY THIS EVENING
FOLLOWED BY A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TONIGHT.
THE BEST CHANCE OF PRECIPITATION WILL BE SOUTHEAST OF TUCSON. A FEW
LINGERING SHOWERS WILL OCCUR ACROSS EASTERN SECTIONS FRIDAY...THEN
DRY CONDITIONS WILL PREVAIL THIS WEEKEND AND EARLY NEXT WEEK.
WIDESPREAD FREEZING TEMPERATURES WILL PREVAIL FRIDAY NIGHT...AND A
HARD FREEZE MAY OCCUR ACROSS THE TUCSON METRO AREA.

&&

.DISCUSSION...SHOWERS HAVE YET TO DEVELOP WEST OF TUCSON AT THIS
TIME AS HAS BEEN CONSISTENTLY ADVERTISED VIA VARIOUS NWP MODELS.
HOWEVER...CLOUDS CONTINUE TO THICKEN ACROSS CENTRAL PIMA COUNTY AND
SRN PINAL COUNTY. HAVE NOTED THAT THE LATEST RUC HRRR DEVELOPS LIGHT
PRECIP ECHOES SW OF TUCSON BY 5 PM MST FOLLOWED BY AN EXPANSIVE AREA
OF PRECIP ECHOES...SOME PERHAPS THAT MAY PRODUCE HEAVY RAINFALL...
FROM THE FAR SRN PORTIONS OF THE TUCSON METRO AREA SWWD INTO SOUTH
CENTRAL PIMA COUNTY EARLY THIS EVENING. THE BULK OF THESE ECHOES ARE
THEN PROGGED TO MOVE SEWD MAINLY ACROSS COCHISE/SANTA CRUZ COUNTIES
LATER THIS EVENING.

AT ANY RATE...HAVE CONTINUED WITH A GOOD CHANCE OF VALLEY RAIN/
MOUNTAIN SNOW SHOWERS MOSTLY FROM TUCSON EWD/SWD THIS EVENING. HAVE
ENDED PRECIP FROM TUCSON WWD LATE TONIGHT...BUT HAVE KEPT SCATTERED
TO NUMEROUS SHOWERS ACROSS ERN SECTIONS. A SLIGHT CHANCE OF SHOWERS
WILL CONTINUE ACROSS ERN SECTIONS FRI MORNING...AND A FEW LINGERING
SHOWERS MAY YET CONTINUE NEAR THE NEW MEXICO BORDER FRI AFTERNOON.
STORM TOTAL LIQUID AMOUNTS AND SNOW ACCUMULATIONS REMAIN UNCHANGED.
THUS...LIQUID AMOUNTS WILL GENERALLY RANGE BETWEEN ONE TENTH OF AN
INCH AND ONE THIRD OF AN INCH...WITH SNOW ACCUMULATIONS OF 2-5
INCHES ABOVE 7000 FEET.

DRY CONDITIONS WILL THEN PREVAIL STARTING FRI EVENING AND CONTINUE
THRU TUE. THE FOCUS OF ATTENTION WILL THEN TURN TOWARD THE NEXT
DEEPENING UPPER TROUGH AND CLOSED LOW OVER THE SWRN CONUS BY THE
MIDDLE OF NEXT WEEK. 25/12Z GFS/ECWMF/CMC WERE IN GOOD AGREEMENT
THAT THIS SYSTEM WILL BRING ANOTHER CHANCE OF VALLEY RAIN/MOUNTAIN
SNOW...ESPECIALLY WED NIGHT AND NEW YEARS DAY. HAVE MAINTAINED A
SLIGHT CHANCE OF SHOWERS ACROSS THE HIGHER TERRAIN EAST OF TUCSON
TUE NIGHT. THERE IS A SLIGHT CHANCE OF VALLEY RAIN/MOUNTAIN SNOW
SHOWERS WED...AND POPS WERE INCREASED WED NIGHT INTO THE CHANCE-
CATEGORY ACROSS ERN SECTIONS. A CHANCE OF MOUNTAIN SNOW SHOWERS WILL
CONTINUE EAST OF TUCSON NEXT THUR...WITH A SLIGHT CHANCE OF SHOWERS
AS FAR WEST AS TUCSON. THIS SYSTEM HOLDS THE POTENTIAL TO PRODUCE
SNOW LEVELS AS LOW AS THE VALLEY FLOORS ACROSS COCHISE COUNTY AND
GRAHAM COUNTY.

FINALLY...A FREEZE WARNING WAS ISSUED FOR MUCH OF PIMA COUNTY AND
SRN PINAL COUNTY LATE FRIDAY NIGHT INTO EARLY SAT MORNING. THE
POTENTIAL EXISTS FOR A HARD FREEZE TO OCCUR ACROSS MUCH OF THE
TUCSON METRO AREA...AT LEAST FOR A FEW HOURS. THUS...THIS FREEZE
WARNING WILL POSSIBLY BE MODIFIED FOR A HARD FREEZE WARNING...
PARTICULARLY FOR ERN PIMA COUNTY INCLUDING TUCSON. OTHERWISE...
DAYTIME TEMPS FRI-SAT WILL BE WELL BELOW SEASONAL NORMALS FOLLOWED
BY A WARMING TREND SUN-MON. EXPECT NEAR NORMAL HIGH TEMPS TUE...
THEN MUCH COOLER TEMPS WILL RETURN WED-THUR.

&&

.AVIATION...VALID THRU 26/23Z.
A LOW PRESSURE SYSTEM MOVING ACROSS THE FOUR CORNERS REGION WILL
RESULT IN SCATTERED TO NUMEROUS -SHRA AND HIGHER TERRAIN -SHSN THIS
EVENING AND TONIGHT...MAINLY FROM TUCSON EASTWARD. SCT-BKN CLOUDS AT
4-7K FT AGL. MVFR CONDITIONS WILL OCCUR AT TIMES...ESPECIALLY ACROSS
HIGHER TERRAIN. ISOLATED -SHRA AND HIGHER TERRAIN -SHSN WILL PREVAIL
EAST OF TUCSON FRIDAY MORNING. SURFACE WIND WILL GENERALLY BE
SWLY/WLY AT 15-30 KTS WITH GUSTS TO AROUND 40 KTS THRU 26/02Z.
DIMINISHING SURFACE WIND THIS EVENING AND TONIGHT...WITH SURFACE
WIND LESS THAN 15 KTS BY 26/10Z. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.

&&

.FIRE WEATHER...A STRONG STORM SYSTEM WILL MOVE THROUGH THE FOUR
CORNERS AREA TONIGHT...AND EAST OF THE REGION ON FRIDAY. BREEZY TO
WINDY CONDITIONS WILL PERSIST INTO THE EARLY EVENING HOURS TONIGHT
BEFORE DIMINISHING. LESS WIND IS EXPECTED OVER THE WEEKEND. THERE
WILL BE A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TONIGHT. A
CONTINUED SLIGHT CHANCE OF SHOWERS WILL OCCUR MAINLY NEAR THE NEW
MEXICO BORDER FRIDAY...FOLLOWED BY DRY CONDITIONS THIS WEEKEND AND
EARLY NEXT WEEK.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
    WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR AZZ503-507-508-
      512-513.

    FREEZE WARNING FROM MIDNIGHT FRIDAY NIGHT TO 9 AM MST SATURDAY
      FOR AZZ501-502-504>506.

&&

$$

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

DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...ZELL




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