Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 031638
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
930 AM MST FRI JUL 3 2015

.SYNOPSIS...EXPECT A STEADY INCREASE IN THE NUMBER OF STORMS INTO
THIS WEEKEND. SLOWER MOVING STORMS WILL START TO INCREASE HEAVY
RAINFALL CONCERNS WITH WET MICROBURSTS POSSIBLE. DAYTIME
TEMPERATURES WILL REMAIN CLOSE TO SEASONAL NORMALS.

&&

.DISCUSSION...NICE LITTLE IMPULSE SHOWING UP ON WATER VAPOR IMAGERY
IN FAR NORTHWEST CHIHUAHUA COMBINED WITH OUTFLOW INTERACTION TO
HELP DRIVE OVERNIGHT CONVECTION ACROSS MUCH OF COCHISE...GRAHAM AND
EASTERN PINAL COUNTIES. STILL CLEARING THE DEBRIS CLOUD WITH
EMBEDDED SHOWERS NORTH AND NORTHEAST. 12Z KTWC SOUNDING AND
SATELLITE ESTIMATES WITH 1.3 TO 1.5 INCHES PRECIPITABLE WATER...BUT
THE FLOW IS VERY WEAK NOW BELOW 500MB WITH A WEAKENING TREND EATING
INTO THE H3 TO H5 LAYER AS WELL. WE SHOULD SEE VERY EASY MOUNTAIN
DEVELOPMENT AREA WIDE TODAY...BUT STORM STRUCTURE WILL STRUGGLE TO
MAINTAIN A FULL LIFE CYCLE IN VALLEY LOCATIONS. ONE CAVEAT TO THAT
IS A REMNANT CONVECTIVE CIRCULATION IN NORTHWEST COCHISE AND
SOUTHWEST GRAHAM COUNTY MOVING NORTHEAST IN A DIMINISHING FLOW. THAT
COULD BE LOCALIZED FOCUS OF CONVECTION NOT BEING PICKED BY HI RES
MODELS.

WE WILL CONTINUE THE GENERAL FORECAST TREND FOR TODAY OF COVERAGE
DOMINATED BY MOUNTAIN AND EASTERN LOCATIONS WITH THE IDEA THAT
OUTFLOW WILL BE INSUFFICIENT FOR SIGNIFICANT DEVELOPMENT INTO WESTERN
AREAS. A QUICK LOOK AT LATEST HRRR AND UOFA WRF-NAM TRENDS PROVIDING
A CERTAIN LEVEL OF COMFORT WITH THIS FORECAST AS WELL.

FOR TONIGHT...A STRONG H7 THETA-E RIDGE THROUGH CENTRAL AND NORTHERN
SONORA ARGUES FOR A POSSIBLE COMPLEX JUST SOUTH OF THE INTERNATIONAL
BORDER EARLY THIS EVENING. PLEASE SEE THE PREVIOUS DISCUSSION FOR
ADDITIONAL DETAILS.

&&

.AVIATION...VALID THRU 04/12Z. SCTD -TSRA/-SHRA MAINLY E OF A KCGZ-
KOLS LINE THIS AM WILL CONT TO MV TO THE W-NW. LCL MVFR CONDS AND
WIND GUSTS TO 30 KTS WITH STRONGEST STORMS AND NR HIER TERRAIN.
CONDS IMPRVG LATER THIS AM BEFORE ANOTHER CHANCE OF -TSRA THIS AFTN
AND EVENG. BRIEF WIND GUSTS THIS AFTN/EVENG OF 30-45 KTS AND MVFR
CONDS PSBL NR THE STRONGEST STORMS. OTHERWISE EXPECT NORMAL DIURNAL
WIND TRENDS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ADEQUATE MOISTURE AND A FAVORABLE FLOW PATTERN WILL
CONTINUE TO PROVIDE AN INCREASING CHANCE OF MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS INTO THE UPCOMING HOLIDAY WEEKEND
WITH HIGH TEMPERATURES WITHIN A FEW DEGREES OF NORMAL.

&&

.PREV DISCUSSION...THE FOURTH OF JULY HOLIDAY WEEKEND IS OFF TO A
FIRECRACKER START WITH NOCTURNAL SCATTERED SHOWERS AND THUNDERSTORMS
MOVING THRU THE PHOENIX METRO...ERN PINAL...GRAHAM...COCHISE AND
GREENLEE COUNTIES THIS MORNING. MOVEMENT OF THESE STORMS HAS BEEN TO
THE W-NW AROUND 10-15 MPH. SOME OF THESE STORMS ARE HEAVY RAINERS
WITH 0.50"-1.25" BEING RECORDED IN SPOTS. THE HEAVIEST HAS OCCURRED
IN GRAHAM COUNTY...ESPECIALLY IN THE PINALENO MOUNTAINS WHERE A
SMALL STREAM FLOOD ADVISORY IS CURRENTLY IN EFFECT. INTERACTIONS
FROM SE AZ OUTFLOWS AND FROM THE NE SONORA MCS ALONG WITH AN
APPROACHING DISTURBANCE...CURRENTLY OVER SW NM/NRN CHIHUAHUA LIKELY
AIDING IN THE DEVELOPMENT OF NOCTURNAL STORMS. THE HRRR HAS BEEN
PLAYING CATCH-UP SINCE LATE LAST NIGHT. WENT WITH HIGHER POPS THIS
MORNING WITH THIS ACTIVITY CONTINUING TO LIFT W-NW. DUE TO THIS
MORNING ACTIVITY...ACTIVITY WILL BE SLOW TO START THIS AFTERNOON AND
MAINLY BE RELEGATED TO THE HIGHER TERRAIN. SCATTERED EVENING STORMS
WITH ISOLATED STORMS CONTINUING DURING THE OVERNIGHT HOURS.

AN ACTIVE WEEKEND IN STORE FOR THE AREA AS IT REMAINS IN A FAVORABLE
MONSOON PATTERN.

FLOW ALOFT BECOMES MORE SOUTHWESTERLY DRYING OUT THE WESTERN AREAS
BUT HOLDING ON TO ENOUGH MOISTURE EASTERN HALF OF THE FORECAST AREAS
FOR CONTINUED CHANCE FOR STORMS.

&&


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

&&

$$

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MEYER/FRANCIS


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