FGZ issues Area Forecast Discussion (AFD) 404 FXUS65 KFGZ 141607 AFDFGZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 900 AM MST MON JUL 14 2014 .SYNOPSIS...DEEP SUBTROPICAL MOISTURE WILL RESIDE ACROSS ARIZONA THROUGH WEDNESDAY...WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY. STARTING THURSDAY...A DRIER AND MORE STABLE AIRMASS WILL MOVE IN AND BRING A SHARP DECREASE IN STORM COVERAGE LASTING THROUGH SATURDAY. && .DISCUSSION... THE SHORT TERM FORECAST IS IN GOOD SHAPE. ANTICIPATED CHANGES TO THE FORECAST STARTING WEDNESDAY NIGHT ARE TO SHARPLY DECREASE PRECIP CHANCES AND CLOUD COVER ACROSS THE BOARD FROM WEDNESDAY NIGHT THROUGH SATURDAY NIGHT. A DRIER AND STABLE AIRMASS TO DEVELOP OVER SW ARIZONA ON WEDNESDAY AND SPREAD NORTHEASTWARD THROUGH SATURDAY. HIGHER TERRAIN AREAS FROM THE KAIBAB PLATEAU THROUGH FLAGSTAFF TO THE WHITE MTNS MAY SEE SCATTERED STORMS ON THURSDAY BUT BY FRIDAY PROGS SHOWING POSITIVE AFTERNOON LIFTED INDEX VALUES ACROSS THE AREA WHICH SUPPORT A DRY FORECAST...ESPECIALLY FOR AREAS BELOW 6000 FEET. && .PREV DISCUSSION...330 AM. WIDELY SCATTERED SHOWER AND THUNDERSTORM ACTIVITY CONTINUES TO DEVELOP INTO THE EARLY MORNING HOURS. THESE STORMS ARE MOVING TOWARDS THE SOUTHWEST IN A NORTHEASTERLY FLOW PATTERN. THE HIGH PRESSURE RIDGE THAT HELPS TO DEFINE THE NORTHWARD EXTENT OF THE MONSOON MOISTURE WILL REMAIN OVER NEVADA AND UTAH TODAY BEFORE DRIFTING SOUTH ACROSS ARIZONA ON TUESDAY. DEEP SUBTROPICAL MOISTURE WILL REMAIN ENTRENCHED ACROSS NORTHERN ARIZONA. HIGH MOISTURE LEVELS AND AIR MASS INSTABILITY WILL PRODUCE A CONTINUED WET MONSOON PATTERN WITH EXTENSIVE CLOUD COVER THROUGH TUESDAY. BY WEDNESDAY...THE RIDGE AXIS WILL MOVE INTO SOUTHERN ARIZONA ALLOWING NORTHWESTERLY FLOW ALOFT TO BRING DRIER AND MORE STABLE AIR INTO ARIZONA FROM THE NORTH RESULTING IN A GRADUAL DOWNWARD TREND IN OUR CHANCES FOR STORM ACTIVITY FROM WEDNESDAY ONWARD. HOWEVER... THERE WILL LIKELY BE ENOUGH MOISTURE AND AIR MASS INSTABILITY FOR ONE MORE DAY OF MORE NORMAL MONSOON SHOWER ACTIVITY. THURSDAY ONWARD...THE RIDGE BEGINS TO MOVE INTO A MOISTURE BLOCKING POSITION WITH THE MID-LEVEL HIGH CENTER LOCATED OVER NORTHERN MEXICO. SOUTHWESTERLY FLOW WILL BRING IN DRIER AIR FROM THE PACIFIC WHICH WILL LIKELY LEAD TO LOWER MOISTURE LEVELS...SLIGHTLY WARMER HIGH TEMPERATURES AND LOWER CHANCES FOR SHOWER AND STORM ACTIVITY INTO THE UPCOMING WEEKEND. && FOR THE 18Z PACKAGE...LOOK FOR SCT TO BKN CIGS 12-15 KFT MSL FOR THE NEXT 24 HOURS. MONSOON MOISTURE WILL REMAIN ACROSS NORTHERN ARIZONA WITH SCATTERED TO NUMEROUS SHRA/TSRA DEVELOPING AFTER 17Z. EXPECT PERIODS OF MVFR VIS UNDER STRONGER STORMS. AFTER 03Z...SHRA/TSRA BECMG ISOLATED. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS. && .FIRE WEATHER...MONSOON MOISTURE WILL REMAIN IN PLACE WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS NORTHERN ARIZONA EACH DAY. HEAVY RAIN IS POSSIBLE WITH STRONGER STORMS. WEDNESDAY THROUGH FRIDAY...DRIER AIR WILL MOVE ACROSS NORTHERN ARIZONA WITH A GRADUALLY DECREASING CHANCE OF SHOWERS AND STORMS. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC.........DL / BOHLIN AVIATION.......RR FIRE WEATHER...MCCOLLUM FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF
Posted on: Mon, 14 Jul 2014 16:08:01 +0000
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