FXUS65 KFGZ 120356
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
900 PM MST SUN MAY 11 2008

.SYNOPSIS...A STRONG...LATE-SEASON LOW PRESSURE SYSTEM AND COLD
FRONT WILL MOVE INTO ARIZONA LATE MONDAY NIGHT AND TUESDAY. AHEAD OF
THIS SYSTEM...EXPECT GUSTY SOUTHWEST WINDS AND CONTINUED MILD
CONDITIONS MONDAY. BY LATE MONDAY NIGHT AND INTO TUESDAY...THE COLD
FRONT WILL BRING AREAS OF RAIN AND HIGH ELEVATION SNOW TO MUCH OF
NORTHERN AND CENTRAL ARIZONA. IN ADDITION...ISOLATED THUNDERSTORMS
CAN BE EXPECTED...ALONG WITH NORTHEAST WINDS...AND MUCH COOLER
TEMPERATURES. NORTHERLY WINDS WILL CONTINUE WEDNESDAY THROUGH
FRIDAY...WITH SLIGHTLY BELOW NORMAL TEMPERATURE AND PARTLY CLOUDY
SKIES.

&&

.DISCUSSION...ALL EYES ARE ON AN DEVELOPING STORM SYSTEM DUE TO
AFFECT MUCH OF THE REGION ON TUESDAY. THIS WILL BE A VERY STRONG AND
COLD SYSTEM FOR THIS LATE IN THE SEASON...WITH PRECIPITATION FALLING
AS SNOW ABOVE 6500-7000 FEET...EVEN AS LOW AS 6000 FEET OVER THE
KAIBAB PLATEAU...AND IN AREAS OF CONVECTION.

AHEAD OF THE STORM...MODERATE SOUTHWEST FLOW WILL CONTINUE OVERNIGHT
TONIGHT AND THROUGH THE DAY MONDAY. WE HAVE A FIRE WEATHER WATCH OUT
FOR MANY AREAS...AND THIS LOOKS GOOD. WIND SPEEDS WILL LIKELY FLIRT
WITH ADVISORY CRITERIA MUCH OF THE AFTERNOON...BUT THE MAJORITY OF
THE SITES SHOULD BE JUST BELOW.

BY LATE MONDAY EVENING...A LOW PRESSURE SYSTEM WILL SEPARATE FROM
THE MAIN FLOW AND DROP SOUTH INTO UTAH AND NORTHERN ARIZONA. THIS
LOW WILL BRIEFLY CLOSE OFF AS IT MOVES SOUTHEAST THROUGH CENTRAL
ARIZONA DURING THE DAY TUESDAY. STRONG FRONTOGENESIS AND DEEP
MOISTURE WILL ACCOMPANY THIS SYSTEM...WITH CRASHING 700MB
TEMPERATURES AND A DESTABILIZING AIRMASS. WINDS WILL SHIFT TO THE
NORTHEAST BEHIND THE FRONT...KEEPING A COOL AND MOIST AIRMASS LOCKED
INTO THE REGION FOR A FEW DAYS.

THE MAIN PRECIPITATION EVENT WILL BE ALONG AND JUST BEHIND THE FRONT
STARTING LATE MONDAY NIGHT OVER THE KAIBAB...AROUND SUNRISE IN THE
FLAGSTAFF AREA...AND LATE TUESDAY MORNING OVER THE WHITE MOUNTAINS.
THE STRENGTH OF THE FRONT WILL CONTRIBUTE TO RAPIDLY FALLING SNOW
LEVELS AND WILL WORK WITH THE INSTABILITY FOR ISOLATED EMBEDDED
NEAR-SEVERE THUNDERSTORMS AT TIMES.

WE WILL BE UPDATING THE GRIDS AND TEXT FOR THE NEXT SHIFT TO HANDLE
THIS SYSTEM MORE AGGRESSIVELY...HOWEVER...NO UPDATES ARE NEEDED TO
THE SHORT TERM PERIOD (TONIGHT AND MONDAY). THE REMAINDER OF THE
WEEK WILL FEATURE COOL NORTHERLY FLOW. A BACKDOOR COLD FRONT MAY
IMPORT ENOUGH MOISTURE FROM THE EAST FOR A FEW SHOWERS THURSDAY
AND FRIDAY.

&&

.AVIATION...FOR THE 06Z PACKAGE...AN APPROACHING STORM SYSTEM WILL
BRING WINDY CONDITIONS BY LATE TOMORROW MORNING...WITH SOUTHWEST
WINDS 15 TO 25 KT WITH GUSTS UP TO 35 KT IN THE AFTERNOON. MID AND
HIGH CLOUDS WILL INCREASE LATE IN THE DAY NORTH OF FLAGSTAFF...WITH
CIGS BKN030-050 AND MVFR VISIBILITIES IN -SHRA SPREADING SOUTH FROM
THE UT BORDER AFT 00Z. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

.FIRE WEATHER...FIRE WEATHER WATCH IN EFFECT FROM MONDAY MORNING
THROUGH MONDAY EVENING FOR STRONG WINDS AND LOW RELATIVE HUMIDITIES.
PLEASE SEE THE FIRE WEATHER WATCH PRODUCT (RFWFGZ) FOR DETAILS. SEE
FIRE WEATHER FORECAST (FWFFGZ) FOR FURTHER DISCUSSION OF DAYS 1 AND
2.

FOR WEDNESDAY THROUGH FRIDAY...EXPECT BREEZY NORTHERLY WINDS EACH
DAY WITH A WEAK TROUGH POSSIBLE ON THURSDAY. THE SYSTEM THURSDAY
WILL BRING SLIGHTLY HIGHER RH VALUES TO NORTHERN ARIZONA...WITH
VALUES IN THE UPPER TEENS TO LOWER TWENTIES. WEDNESDAY AND FRIDAY
WILL BE A LITTLE DRIER WITH RH VALUES GENERALLY IN THE LOW TO UPPER
TEENS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...FIRE WEATHER WATCH FROM MONDAY
MORNING THROUGH MONDAY EVENING FOR ARIZONA FIRE WEATHER ZONES
AZZ104>117-139-140

&&

$$

PUBLIC...PETERSON
AVIATION/FIRE WEATHER...BK

VISIT WEATHER.GOV/FLAGSTAFF FOR MORE NORTHERN ARIZONA WEATHER
INFORMATION.