

Dennis
AFDFLG
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
315 AM MST WED MAY 21 2003
.SYNOPSIS...HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. EXPECT WARM AND DRY WEATHER WITH OCCASIONAL HIGH
CLOUDS. THE ONLY EXCEPTION WILL BE ALONG THE EASTERN BORDER WHERE
THERE WILL BE A CHANCE OF DRY THUNDERSTORMS EACH AFTERNOON.
.DISCUSSION...MOISTURE IS EVIDENT AT THE SURFACE ALONG THE NEW
MEXICO BORDER AS KRQE AND KSJN ARE SHOWING DEW POINTS IN THE MID
30'S TO LOWER 40'S. THIS IS MOISTURE FROM YESTERDAYS BACK DOOR
FRONT. EVEN THOUGH MOISTURE IS MUCH LESS OVER THE WESTERN MOGOLLON
RIM, VIRGA AND LIGHT PRECIP OCCURRED IN THE FLAG AREA. WE WILL
EXPAND THE PRECIP AREAS TODAY AND AGAIN ON THURSDAY AS CONDITIONS
CONTINUE TO REMAIN THE SAME UNDER HIGH PRESSURE. WE WILL KEEP PARTLY
CLOUDY AND DRY CONDITIONS GOING ON FRIDAY, AS MID LEVEL FLOW TURNS
MORE WESTERLY ON FRIDAY, TO PUSH MOISTURE EAST OF THE AREA. AS A
WEATHER SYSTEM APPROACHES FROM THE WEST ON SATURDAY, LAPSE RATES
STEEPEN IN RESPONSE TO COOLING AT 500 MB. THERE IS ENOUGH
MID-LEVEL MOISTURE FOR ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
STRETCHING FROM THE KAIBAB PLATEAU INTO THE FOUR CORNERS AREA.
PRECIP CHCS WERE SPREAD ACROSS ALL OF OUR NORTHERN ZONES. A DRY PUSH
OF AIR COMES UNDERNEATH THE LOW HELPING TO DRY SOUTHERN ZONES WITH
LITTLE THREAT OF -TRW/-RW. AFTER THE LOW PASSES TO THE EAST ON
MONDAY THE FOUR CORNER HIGH COMES BACK...ALLOWING A RETURN OF
MID-LEVEL SUBTROPICAL MOISTURE BACK INTO EASTERN SECTIONS OF THE
STATE...WOULD NOT BE SURPRISED TO SEE AND INCREASE IN -RW/-TRW
WEDNESDAY INTO THURSDAY. FOR NOW WE WILL HANDLE THE DAY 7 PART OF
THE EXTENDED WITH PARTLY CLOUDY SKIES.