332
FXUS65 KFGZ 130413
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
910 PM MST MON AUG 12 2013
.SYNOPSIS...DRIER AND MORE STABLE AIR WILL CONTINUE TO LIMIT RAIN
AND THUNDERSTORM ACTIVITY ACROSS NORTHERN ARIZONA THROUGH WEDNESDAY.
THUNDERSTORM CHANCES WILL SLOWLY INCREASE EACH DAY FROM THURSDAY
ONWARD AS THE MID LEVEL HIGH PRESSURE RIDGE MOVES EAST INTO NEW
MEXICO AND ALLOWS DEEP MOIST SOUTHERLY FLOW TO SET UP ACROSS ARIZONA.
&&
.DISCUSSION...A DRIER AIR MASS WILL PERSIST OVER MUCH OF NORTHERN
ARIZONA THROUGH AT LEAST WEDNESDAY. THE SOURCE OF THIS DRIER AIR IS
FROM SOUTHWESTERLY FLOW OFF THE PACIFIC. DEEPER SUBTROPICAL MOISTURE
IN MEXICO HAS BEEN SUPPRESSED BY AN UNFAVORABLE POSITION OF THE
SUBTROPICAL RIDGE INTERACTING WITH TROUGHS MOVING IN ALONG THE WEST
COAST. LARGE SCALE SUBSIDENCE ALOFT WILL PRODUCE DOWNWARD MOTIONS
AND HELP TO CAP AND CONVECTIVE DEVELOPMENT THROUGH WEDNESDAY.
ONE HITCH IN THIS SHORT TERM DRIER FORECAST IS A SUBTROPICAL
DISTURBANCE WHICH MOVED ACROSS THE MOUTH OF THE GULF OF CALIFORNIA
ON SUNDAY NIGHT. THIS PRESSURE PATTERN SHIFT COULD INITIATE STRONG
SOUTHERLY FLOW ALONG THE GULF AND OVER A 24 TO 48 HOUR PERIOD BRING
UP A GULF MOISTURE SURGE INTO SOUTHERN AND WESTERN ARIZONA. THE
IMPACTS OF THIS SURGE WILL DEPEND ON THE INTENSITY AND MAY CAUSE US
TO INCREASE PRECIPITATION CHANCES FROM WEDNESDAY AFTERNOON INTO
THURSDAY.
THURSDAY THROUGH SUNDAY...THE SUBTROPICAL HIGH SLOWLY SHIFTS
EASTWARD INTO NEW MEXICO AS A STRONGER TROUGH MOVES IN ALONG THE
WEST COAST. DEEPER SOUTHERLY FLOW WILL DEVELOP ACROSS ARIZONA WHICH
WILL TAP INTO HIGHER MOISTURE LEVELS IN MEXICO...SLOWLY INCREASING
OUR CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.AVIATION...FOR THE 06Z PACKAGE...VFR CONDITIONS FOR THE NEXT 24
HOURS. ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP TUESDAY AFTER 18Z EAST OF A LINE FROM PAYSON (KPAN) TO PAGE
(KPGA). AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC.........BOHLIN
AVIATION.......BOHLIN
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF