Area Forecast Discussion
Issued by NWS Tucson, AZ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KTWC 291707
AFDTWC

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TUCSON AZ
1005 AM MST THU JAN 29 2015

CORRECTED DISCUSSION THIRD PARAGRAPH

.SYNOPSIS...A STORM SYSTEM WILL BRING VALLEY RAIN AND MOUNTAIN SNOW
ESPECIALLY TONIGHT INTO SATURDAY. MINOR FLOODING MAY OCCUR DUE TO
PERIODS OF HEAVY RAINFALL. THE MOST SIGNIFICANT SNOWFALL WILL BE
ABOVE 8000 FEET...OR ACROSS THE HIGHEST PEAKS. EXPECT MUCH COOLER
DAYTIME TEMPERATURES FRIDAY INTO THIS WEEKEND. DRY CONDITIONS WITH A
WARMING TREND WILL THEN OCCUR EARLY NEXT WEEK.

&&

.DISCUSSION...UPPER LEVEL TROUGH WAS WEST OF THE SRN CALIFORNIA/BAJA
CALIFORNIA COASTS WITH 570 DM LOW CENTERED NEAR 27N/123W THIS
MORNING. THIS SYSTEM WILL MOVE EWD INTO THE SWRN CONUS TONIGHT AND
REMAIN QUASI-STATIONARY INTO SAT. ABUNDANT MOISTURE WILL MOVE INTO
THE AREA...WITH TOTAL PRECIP WATER VALUES TO APPROACH 1.20 INCHES BY
SAT. ISOLATED TO SCATTERED SHOWERS PRODUCING MOSTLY SPRINKLES THIS
MORNING WILL BECOME SCATTERED TO NUMEROUS SHOWERS PRODUCING
POTENTIALLY LOCALLY HEAVY RAINFALL TONIGHT AND CONTINUING FRI.
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS FRI AND FRI EVENING DUE
TO WEAK INSTABILITY WITH MUCAPE AOB 300 J/KG.

RAINFALL INTENSITY SHOULD DECREASE PERHAPS AS EARLY AS FRI
AFTERNOON...BUT MORE LIKELY FRI NIGHT AND ESPECIALLY SAT. HOWEVER...
AMPLE MOISTURE CONTINUING ACROSS THE AREA IN COMBINATION WITH WEAK
SYNOPTIC SCALE ASCENT DUE TO THE PRESENCE OF THE UPPER LOW WILL LEAD
TO WIDESPREAD SHOWER COVERAGE. A SLIGHT CHANCE OF THUNDERSTORMS
CONTINUES SAT DUE TO A PROGGED ENVIRONMENT OF WEAK AOB 300 J/KG
MUCAPE. THE UPPER LOW IS PROGGED TO FILL AND MOVE SWD INTO THE NRN
GULF OF CALIFORNIA SAT NIGHT...THEN CONTINUE TO MOVE SLOWLY SEWD
ACROSS SONORA MEXICO SUN. THERE APPEARS TO BE ENOUGH RESIDUAL
MOISTURE TO MAINTAIN A SLIGHT CHANCE OF SHOWERS EAST-TO-SOUTH OF
TUCSON SUN.

STORM TOTAL LIQUID AMOUNTS ARE FORECAST TO GENERALLY RANGE FROM 0.50
TO 1.50 INCHES IN THE VALLEYS...WITH SOME AMOUNTS IN EXCESS OF 2.00
INCHES POSSIBLE. LIQUID AMOUNTS ACROSS THE MOUNTAINS WILL GENERALLY
RANGE FROM 1.00 - 2.00 INCHES. HOWEVER...LIQUID AMOUNTS IN EXCESS OF
2 INCHES SHOULD OCCUR ACROSS SOME MOUNTAINS...PARTICULARLY FROM THE
CATALINA/RINCON MOUNTAINS NEAR TUCSON NEWD TO THE WHITE MOUNTAINS.

SNOW LEVELS FRI MORNING WILL BE AROUND 9000 FEET. SNOW LEVELS WILL
THEN LOWER TO AROUND 8000 FEET FRIDAY EVENING...AND CONTINUE TO
LOWER TO NEAR 7500 FEET BY MIDDAY SATURDAY. STORM TOTAL SNOW
ACCUMULATIONS SHOULD APPROACH OR EXCEED 2 FEET IN THE WHITE
MOUNTAINS ABOVE 7000 FEET...WITH 18-22 INCHES OF SNOWFALL ABOVE 7000
FEET FURTHER SWWD ACROSS THE PINALENO MOUNTAINS INCLUDING MOUNT
GRAHAM. STORM TOTAL SNOW ACCUMULATIONS ARE FORECAST TO RANGE BETWEEN
12-16 INCHES ACROSS THE CATALINA/RINCON MOUNTAINS ABOVE 7000 FEET.

DRY CONDITIONS WILL THEN PREVAIL SUN NIGHT-WED. HIGH TEMPS TODAY
WILL AVERAGE ABOUT 5-10 DEGS F OR SO ABOVE NORMAL. EXPECT ABOUT
10-15 DEGS F OF COOLING FRI FOLLOWED BY SLIGHTLY COOLER TEMPS SAT.
A WARMING TREND WILL THEN OCCUR SUN-MON...THEN NO SIGNIFICANT CHANGE
IN DAYTIME TEMPS WILL HAPPEN TUE-WED.

&&

.AVIATION...VALID THRU 30/18Z.
A STRONG LOW PRESSURE SYSTEM WILL MOVE EASTWARD ACROSS SOUTHEAST
ARIZONA INTO SATURDAY. FLYING CONDITIONS WILL RAPIDLY DETERIORATE
INTO FRIDAY MORNING...WITH CLOUD DECKS MAINLY ABOVE 10K FT AGL THIS
MORNING FOLLOWED BY SCATTERED TO BROKEN CLOUDS AROUND 3-6K FT AGL
AND OVERCAST CLOUD DECKS ABOVE 6K FT AGL BY THIS EVENING. ISOLATED
-SHRA WILL OCCUR INTO THIS AFTERNOON...THEN SCATTERED TO NUMEROUS
-SHRA DEVELOPING THIS EVENING. CIGS AND VSBYS WILL DECREASE EVEN
FURTHER DURING THIS PERIOD WITH AREAS OF MVFR CONDITIONS LIKELY
BEFORE SUNRISE FRIDAY. SURFACE WIND WILL BE SELY/SLY AT 10-15
KTS...WITH THE STRONGEST AND GUSTIEST WINDS ALONG THE NEW MEXICO
BORDER AND ALONG THE GILA RIVER VALLEY. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A STORM SYSTEM WILL BRING WIDESPREAD VALLEY RAIN AND
MOUNTAIN SNOW MAINLY TONIGHT INTO SATURDAY. THE MOST SIGNIFICANT
SNOWFALL WILL OCCUR ACROSS THE HIGHEST PEAKS OF THE WHITE
MOUNTAINS...MOUNT GRAHAM...AND THE CATALINA AND RINCON MOUNTAINS
NEAR TUCSON. A FEW LINGERING SHOWERS WILL OCCUR MAINLY EAST TO SOUTH
OF TUCSON SUNDAY...THEN DRY CONDITIONS WILL PREVAIL MONDAY THROUGH
WEDNESDAY.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
    WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING
    FOR AZZ510-511-514 ABOVE 7000 FEET.

&&

$$

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

FRANCIS




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.