Dust Devil in Arizona, April 6, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST MON APR 6 2015

.SYNOPSIS...WINDY AFTERNOONS WILL CONTINUE THE NEXT FEW DAYS WITH A
COOL DOWN IN TEMPERATURES WEDNESDAY AND THURSDAY.  THEN ANOTHER
SYSTEM WILL PASS BY CLOSE TO THE REGION LATER THIS WEEKEND BRINGING
A SLIGHT THREAT OF SHOWERS AND COOLER TEMPERATURES.

&&

.DISCUSSION...DRY SW FLOW ALOFT WILL CONTINUE INTO WEDNESDAY AND
IS PLAINLY VISIBLE ON THE WATER VAPOR IMAGERY AS IS THE UPPER LOW
OFF THE SOUTH OREGON COAST THAT WILL AFFECT MUCH OF THE WESTERN US
THROUGH WEDNESDAY.  AS THIS LOW SLOWLY MOVES TO THE SE THEN
EAST...THE WIND ALOFT WILL CONTINUE TO BE ELEVATED THROUGH WEDNESDAY
AND THIS WIND WILL MIX DOWN AGAIN TUESDAY AND WEDNESDAY AFTERNOONS.
WINDS WILL BE A BIT STRONGER TUESDAY VS TODAY AND ENOUGH TO CAUSE
FIRE WEATHER CONCERNS EASTERN THIRD OF THE AREA.  WITH THE UPPER LOW
SLOWLY APPROACHING...AFTERNOON TEMPERATURES WILL BE A FEW DEGREES
COOLER TUESDAY DESPITE PLENTY OF SUNSHINE.

THEN BY WEDNESDAY THE LOW IS HEADING EAST ACROSS THE GREAT BASIN FOR
OUR FINAL DAY OF WIDESPREAD WESTERLY BREEZES...MORE WEST-NORTHWEST
THAN SOUTHWEST.  THE FOCUS OF THE STRONGER WINDS WILL SHIFT A BIT
FURTHER EAST.  BY THIS POINT COLD ADVECTION WILL SHOW ITSELF WITH
HIGHS 5-9 DEGREES COOLER THAN TUESDAY AND ACTUALLY END UP BELOW
NORMAL FOR MOST AREAS.  THESE COOLER TEMPERATURES WILL CONTINUE INTO
THURSDAY BEFORE BEGINNING TO REBOUND FRIDAY AS A WEAK UPPER LEVEL
RIDGE MOVES OVERHEAD.

THEN ATTENTION SHIFTS TO WHAT MAY HAPPEN THIS WEEKEND.  GUIDANCE
HAS AND CONTINUES TO INDICATE SOME FORM OF A TROUGH MOVING EAST
ACROSS THE SOUTHWEST.  SIGNIFICANT DIFFERENCES IN TIMING...LOCATION
AND ATTENDANT MOISTURE HAVE BEEN THE RULE FROM MODEL TO MODEL AND
RUN TO RUN.  AT THIS POINT I TWEAKED THE POPS JUST A BIT SATURDAY
NIGHT...PUSHING IT UP TO NEAR CLIMO AT LEAST...AND ADJUSTING SUNDAY
UP A TOUCH AS THOSE SEEM TO BE THE BEST PERIODS TO SEE ANYTHING AT
THIS TIME.  STILL ONLY LOOKING A SLIGHT CHANCE POPS HOWEVER.  AFTER
A NEAR NORMAL HIGH TEMPERATURE DAY ON SATURDAY WE SHOULD SEE SEVERAL
DEGREES COOLING FOR SUNDAY ON THE BACKSIDE OF THIS FEATURE.
CERNIGLIA

&&

.AVIATION...VALID THRU 08/00Z.
CLEAR SKIES THROUGH THE EARLY EVENING. CIRRUS CLOUDS /ABOVE 25 KFT
MSL/ WILL INCREASE OVERNIGHT INTO TUESDAY. SOUTHWEST SURFACE WIND
16-24 KTS WITH STRONGER GUSTS HIS AFTERNOON. THE STRONGEST SURFACE
WIND WILL BE EAST OF KTUS IN THE VICINITY OF KDUG...KFHU AND KALK.
WINDS AFTER 07/04Z WILL DIMINISH TO LESS THAN 12 KTS. WINDS WILL
AGAIN BECOME SW 16-24 KTS WITH STRONGER GUSTS TUESDAY AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A LARGE-SCALE TROUGH OF LOW PRESSURE ALOFT ALONG THE
WEST COAST WILL MOVE SLOWLY EAST THE NEXT SEVERAL DAYS. THIS WILL
RESULT IN STRONG AND GUSTY WINDS ACROSS THE REGION THROUGH
WEDNESDAY. THE COMBINATION OF THESE WINDS AND A DRY AIRMASS WILL
RESULT IN CRITICAL FIRE WEATHER CONDITIONS. A RED FLAG WARNING IS IN
EFFECT THROUGH 8 PM MST TODAY AND 11 AM THROUGH 8 PM TUESDAY FOR ALL
OF FIRE WEATHER ZONES 152 AND 153...AS WELL AS THE SOUTHEAST PORTION
OF FIRE WEATHER ZONE 151...FOR THE COMBINATION OF STRONG AND GUSTY
WINDS...LOW RELATIVE HUMIDITY AND A HIGH FIRE DANGER.  THIS WARNING
INCLUDES ALL OF GREENLEE...GRAHAM AND COCHISE COUNTIES...AS WELL AS
EASTERN SANTA CRUZ AND FAR SOUTHEAST PIMA COUNTIES.

CRITICAL FIRE WEATHER CONDITIONS MAY BE PRESENT WEDNESDAY AS WELL
ALTHOUGH AN INCREASE IN HUMIDITIES MAY LIMIT THE OVERALL
COVERAGE...ESPECIALLY IN HIGHER ELEVATIONS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FOR AZZ151>153
 (SOUTHEAST PORTIONS OF 151 AND ALL OF 152 AND 153) THROUGH 8 PM
 THIS EVENING AND TUESDAY FROM 11 AM UNTIL 8 PM MST BOTH DAYS.

&&

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