Severe Thunderstorm Warning 49, NWS Flagstaff, AZ

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
900 AM MST TUE SEP 14 1999

SYNOPSIS...A PACIFIC WEATHER DISTURBANCE WILL MOVE ACROSS NORTHERN
ARIZONA TODAY AND WEDNESDAY BRINGING MOSTLY CLOUDY SKIES AND
WIDESPREAD SHOWERS AND THUNDERSTORMS. A DRYING TREND WILL BEGIN ON
THURSDAY AND FRIDAY BUT SOME MOISTURE ALONG WITH A CHANCE OF
THUNDERSTORMS WILL LINGER OVER EASTERN ARIZONA.

DISCUSSION...CURRENT FORECAST LOOKS GOOD WITH NO UPDATES. A SHORT
WAVE TROUGH CONTINUES TO APPROACH NORTHERN ARIZONA FROM THE WEST.
AT 250 MB THE REAR ENTRANCE REGION OF A JET MAX WILL EXTEND ACROSS
NORTHERN ARIZONA WITH A Q-VECTOR ANALYSIS INDICATING UPWARD
FORCING. THIS WILL RESULT IN A GENERAL STRENGTHENING OF THE
BAROCLINIC ZONES ACROSS ARIZONA WITH A GRADUAL COOLING OF THE AIR
MASS. AROUND THE 700 MB LEVEL ANTICYCLONIC CIRCULATION OVER FAR
SOUTHEAST ARIZONA CONTINUES TO ADVECT MOISTURE INTO WESTERN AND
CENTRAL ARIZONA. THIS MOISTURE IS MOVING INTO AN AREA OF LOW TO MID
LEVEL ISENTROPIC LIFT OVER CENTRAL AND NORTHERN ARIZONA THIS
MORNING. THE ETA IS SHOWING AS MUCH AS 100 MB OF LIFT BETWEEN FAR
SOUTHWEST AND NORTHERN ARIZONA. THIS APPEARS REASONABLE SINCE
GENERAL CLOUDINESS CONTINUES TO DEVELOP ACROSS NORTHERN ARIZONA
THIS MORNING WITH EMBEDDED SHOWERS AND THUNDERSTORMS. ACCORDING TO
THE ETA THIS REGION OF ISENTROPIC LIFT CONTINUES INTO WEDNESDAY. AS
A RESULT...THINK SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD TODAY
AND TONIGHT AND WILL LIKELY EXTEND INTO WEDNESDAY. THERE IS SOME
SHEAR ALOFT AND WITH DECENT CAPE VALUES DEVELOPING TODAY OVER
YAVAPAI AND NORTHERN GILA COUNTIES WOULDNT BE SURPRISED TO SEE A
FEW SEVERE STORMS (MAIN THREAT LARGE HAIL). WITH PERSISTENT MOIST
FLOW FROM THE SOUTHWEST CANT RULE OUT SOME LOCALIZED FLOODING
ESPECIALLY NEAR THE MOGOLLON RIM WHERE CELL TRAINING MAY OCCUR.
OTHERWISE...DO NOT EXPECT A WIDESPREAD FLASH FLOOD THREAT.

MCCOLLUM.

.FLG...NONE.