000
FNUS21 KWNS 171637
FWDDY1
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1136 AM CDT THU MAY 17 2012
VALID 171700Z - 181200Z
...CRITICAL FIRE WEATHER AREA FOR OWENS VALLEY...GREAT
BASIN...NORTHWEST ARIZONA...
...OWENS VALLEY...GREAT BASIN...NORTHWEST ARIZONA...
NO CHANGES WERE MADE TO THE CURRENT CRITICAL AREA. EARLY MORNING
SURFACE OBSERVATIONS INDICATE VERY POOR OVERNIGHT RH RECOVERY ACROSS
NW AZ/SRN NV/SW UT AND RH VALUES ARE ALREADY BELOW 15 PERCENT. AS
HEATING MIXES THE BOUNDARY LAYER AND HEIGHTS FALL IN CONJUNCTION
WITH THE APPROACHING TROUGH...BOTH SUSTAINED WIND SPEEDS AND GUST
FREQUENCY/INTENSITY SHOULD INCREASE ACROSS THIS ENTIRE REGION.
HIGH-END CRITICAL CONDITIONS ARE EXPECTED ACROSS NW AZ/SRN NV/FAR SW
UT AS 20-25 MPH SUSTAINED SLY WINDS WITH GUSTS TO NEAR 40 MPH...RH
VALUES IN THE SINGLE DIGITS...VERY WARM TEMPERATURES...AND VERY DRY
FUELS ARE ALL JUXTAPOSED FOR MORE THAN 8 HOURS. ONLY FACTOR LIMITING
EXTREMELY CRITICAL CONDITIONS IS WIND SPEEDS. FARTHER NW /CNTRL AND
WRN NV...OWENS VALLEY/...CRITICAL CONDITIONS ARE EXPECTED TO DEVELOP
BY THE AFTERNOON JUST AHEAD OF A COLD FRONT MOVING SEWD THROUGH THE
NRN GREAT BASIN. NWLY WINDS...INCREASED MOISTURE...AND SLIGHTLY
COOLER TEMPERATURES ARE EXPECTED BEHIND THIS FRONT. THIS FRONT WILL
LIKELY EXTEND FROM SRN NV NEWD TO NRN UT BY THE END OF THE PERIOD.
...SWRN WY AND WRN CO...
NO CHANGES NEEDED. DRY TSTM ACTIVITY IS EXPECTED TO BE VERY
BRIEF/ISOLATED AS THIS AREA HAS WEAK INSTABILITY/MARGINAL SHEAR.
BEST THUNDERSTORM CHANCES WILL BE FARTHER N /NRN ROCKIES/ BUT
LOW-LEVEL MOISTURE IS HIGH ENOUGH TO LIMIT DRY TSTM ACTIVITY AND
THREAT OF LIGHTNING-CAUSED IGNITION.
...TX PANHANDLE NEWD INTO SWRN MN...
NO CHANGES NEEDED. SUSTAINED 20-25 MPH SLY WINDS WITH GUSTS TO 30
MPH ARE EXPECTED ACROSS A LARGE PORTION OF THE PLAINS. TEMPERATURES
ARE ALSO EXPECTED TO BE 10 TO 15 DEG F ABOVE NORMAL.
HOWEVER...WIDESPREAD GREEN UP SHOULD KEEP THE FIRE WEATHER THREAT
LOW.
..MOSIER.. 05/17/2012
.PREV DISCUSSION... /ISSUED 0208 AM CDT THU MAY 17 2012/
...SYNOPSIS...
AN AMPLIFIED UPPER TROUGH WILL IMPACT THE WEST...WITH STRONGER JET
WINDS SPREADING ACROSS CA...THE GREAT BASIN AND AZ. AN ATTENDANT
SURFACE TROUGH WILL DEVELOP FROM THE NRN PLAINS SWWD INTO THE GREAT
BASIN IN ADVANCE OF THE UPPER TROUGH...SUPPORTING A BROAD SWATH OF
STRENGTHENED SURFACE WINDS OVER PORTIONS OF THE SOUTHWEST...GREAT
BASIN...AND CNTRL U.S.
ACROSS THE NORTHEAST...A POTENT UPPER TROUGH AN ITS ATTENDANT
SURFACE COLD FRONT WILL QUICKLY SHIFT OFFSHORE...WITH A DRIER
POST-FRONTAL AIR MASS SETTLING OVER THE REGION.
...OWENS VALLEY...GREAT BASIN...NORTHWEST ARIZONA...
WLY/SWLY SURFACE WINDS WILL BEGIN TO STRENGTHEN IN ADVANCE OF THE
UPPER TROUGH...WITH SUSTAINED SPEEDS NEAR 20 TO 25 MPH. AMPLE
SURFACE HEATING WILL CONTRIBUTE TO A DEEPLY MIXED BOUNDARY
LAYER...WITH STRONG GUSTS OF 30 TO 40 MPH REACHING THE
SURFACE...PARTICULARLY OVER THE SRN GREAT BASIN. GIVEN THE
ANTECEDENT DRY AIR MASS AND DOWNSLOPE COMPONENT TO THE WINDS...WELL
ABOVE NORMAL TEMPERATURES AND SINGLE DIGIT RELATIVE HUMIDITIES
APPEAR PROBABLE ACROSS A BROAD AREA. BY EVENING...WINDS ARE EXPECTED
TO SHIFT TO NWLY OVER THE WRN GREAT BASIN AS A COLD FRONT PROGRESSES
THROUGH THE AREA...THOUGH RELATIVE HUMIDITIES WILL BE SLOW TO
RECOVER. THE FRONT WILL REACH THE SRN GREAT BASIN LATE IN THE
PERIOD.
...SWRN WY AND WRN CO...
REMNANT MID-LEVEL MOISTURE AND A SUBTLE MID-UPPER LEVEL LOW OBSERVED
OVER THE UT/WY/CO BORDER ON 07Z WV IMAGERY WILL SUPPORT ISOLATED DRY
THUNDERSTORMS THIS AFTERNOON AND EVENING AS DIURNAL DESTABILIZATION
OCCURS. WEAK INSTABILITY SHOULD LIMIT COVERAGE.
...TX PANHANDLE NEWD INTO SWRN MN...
LOW LEVEL SLY WINDS WILL BEGIN TO STRENGTHEN OVER MUCH OF THE CNTRL
U.S. AS A WRN UPPER TROUGH APPROACHES. DRY SLY RETURN FLOW AND
SEASONABLY WARM TEMPERATURES WILL HEIGHTEN THE FIRE THREAT IN ANY
AREAS THAT REMAIN DRY...THOUGH WIDESPREAD GREEN UP SHOULD GENERALLY
MITIGATE THE THREAT.
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
