Severe Thunderstorm Warning 23, NWS Flagstaff, AZ

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
850 AM MST WED JUL 22 1998

SYNOPSIS...PLENTY OF MOISTURE ACROSS THE STATE WILL ALLOW SCATTERED
THUNDERSTORMS TO DEVELOP OVER THE NORTHLAND. HEAVY RAIN IS EXPECTED
ACROSS THE SOUTHWESTERN PARTS OF THE STATE...WHILE MODERATE RAIN AND
GUSTY WINDS ARE LIKELY ACROSS THE NORTHEAST. WITH THIS ABUNDANT
MOISTURE IN PLACE...SCATTERED THUNDERSTORMS WILL DEVELOP EACH DAY
THROUGH THE END OF THE WEEK.

DISCUSSION...FIRST PROBLEM OF THE DAY IS POTENTIAL FOR FLASH
FLOODING. DEEPEST MOISTURE AXIS GENERALLY OVR SOUTHWEST THIRD OF
STATE WITH MODIFIED FGZ SOUNDING SHOWING A LITTLE OVR AN INCH PRECIP
H2O. CLEARING OVR RIM COUNTRY SHOULD HAVE THINGS POPPING BY MIDDAY
WITH FLOW MOVING STORMS WESTWARD INTO AREA WHICH HAS RECEIVED HEAVY
RAINFALL LAST FEW DAYS. SO WL ISSUE FLASH FLOOD WATCH FOR ZNS 8 AND
18 FROM 11 AM UNTIL 10 PM. CAPE ON MODIFIED SOUNDING ALSO UP TO
NEARLY 1500 J/KG...BUT SHEAR IS WEAK...SO LOOKING FOR SMALL HAIL AND
MAYBE AN ISOLATED SEVERE HAILER POSSIBLE. SMALL STREAM FLOODING QUITE
POSSIBLE RIM COUNTRY AND NEARBY DRAINAGE AREAS TOWARD THE NORTH AS
WELL. TWO FLYS IN ALL THIS IS IF WE GET TO MUCH ACTIVITY TO SUPPORT
STRONG ISOLD CONVECTION...AND LACK OF OBVIOUS UPPER LEVEL TRIGGER IN
FLOW. THERE IS OFTEN A MINOR DISTURB WHICH SNEAKS IN ON US IN THE
FLOW.

WL FRET OVR LATER PERIODS TAFTN...BUT FOR NOW DO NOT SEE ANY LARGE
SCALE CHGS WITH MONSOON DFORECAST CONDITIONS PREVAILING MOST AREAS.

FLG 734  INW 212
BET
FLG...FLASH FLOOD WATCH 11 AM TO 10 PM MST FOR ZNS 8 AND 18.

AZZ004>018-221900-

AREA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
915 AM MST WED JUL 22 1998

...FLASH FLOOD WATCH FOR PORTIONS OF NORTHERN ARIZONA TODAY...

SPOTTER ACTIVATION MAY BE REQUIRED BY EARLY AFTERNOON DUE TO
POTENTIAL FOR FLOODING AND HAIL.

DISCUSSION...A DEEP MOISTURE AXIS SITS OVER THE WESTERN THIRD OF
ARIZONA TODAY WITH CONSIDERABLE MOISTURE IN THE CENTRAL SECTIONS AS
WELL. MORNING LOW CLOUDS HAVE DISSIPATED OVER CENTRAL SECTIONS
LEAVING SUNNY SKIES OVER RIM COUNTRY EASTWARD THIS MORNING. THIS WILL
ALLOW PLENTY OF HEATING TO KICK OFF THUNDERSTORMS AROUND MIDDAY OVER
THE MOGOLLON RIM AND EASTERN MOUNTAINS MOVING WESTWARD INTO YAVAPAI
AND GILA COUNTIES BY MIDAFTERNOON. VERY HEAVY RAIN AND MAINLY SMALL
HAIL ARE LIKELY IN THESE AREAS AND HAS PROMPTED A FLASH FLOOD WATCH
FOR YAVAPAI AND NORTHERN GILA COUNTIES UNTIL 10 PM MST.

HEAVY RAIN LAST NIGHT NORTH OF WINSLOW HAS CAUSED MINOR FLOODING OF
STREAMS AND WASHES OVER CENTRAL NAVAJO COUNTY. ISOLATED THUNDERSTORMS
WITH HEAVY RAIN MAY AGGRAVATE THIS SITUATION LATE TODAY.

BT