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000
FNUS22 KWNS 181602
FWDDY2

DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1101 AM CDT TUE JUN 18 2013

VALID 191200Z - 201200Z

...CRITICAL FIRE WEATHER AREA FOR THE SERN HALF OF UT...PORTIONS OF
WRN/CNTRL/SRN CO...PORTIONS OF CNTRL/NRN/WRN NM...NRN AZ...EXTREME
SERN NV...
...CRITICAL FIRE WEATHER AREA FOR THE FOLLOWING LOCATIONS IN SRN
CA----MUCH OF THE ERN TWO-THIRDS OF SANTA BARBARA COUNTY...THE NRN
TWO-THIRDS OF VENTURA COUNTY...NWRN/N-CNTRL LOS ANGELES
COUNTY...PARTS OF FAR SRN KERN COUNTY...

NO CHANGES REQUIRED.  PLEASE SEE PREVIOUS DISCUSSION FOR FORECAST
DETAILS.

..LEITMAN.. 06/18/2013

.PREV DISCUSSION... /ISSUED 0433 AM CDT TUE JUN 18 2013/

...SYNOPSIS...
IN THE MID LEVELS...A STRONG AND NEGATIVELY TILTED SHORTWAVE TROUGH
WILL ADVANCE NEWD FROM PARTS OF THE CNTRL GREAT BASIN TO THE NRN
ROCKIES AND THE ADJACENT HIGH PLAINS THROUGH THE PERIOD...AROUND A
MID-LEVEL CYCLONE SLOWLY PROGRESSING EWD FROM THE PACIFIC NW TO THE
NRN ROCKIES. A ZONE OF STRONG TROPOSPHERIC FLOW ACCOMPANYING THIS
SHORTWAVE TROUGH WILL BRUSH ACROSS DRY/VERY DRY SFC CONDITIONS
OVERLYING PARTS OF THE CNTRL GREAT BASIN...THE CNTRL/SRN
ROCKIES...AND THE SW STATES TO ENHANCE THE FIRE WEATHER THREAT. A
SEPARATE AREA OF CRITICAL FIRE WEATHER CONDITIONS IS FORECAST ACROSS
PORTIONS OF SRN CA. MEANWHILE...A MID-LEVEL RIDGE WILL ADVANCE EWD
ACROSS PORTIONS OF THE CNTRL CONUS...WHILE A SHORTWAVE TROUGH MOVES
OFF THE ATLANTIC COAST.

...THE SERN HALF OF UT...PORTIONS OF WRN/CNTRL/SRN CO...PORTIONS OF
CNTRL/NRN/WRN NM...NRN AZ...EXTREME SERN NV...
---WINDS----
AS THE AFOREMENTIONED ZONE OF STRONG TROPOSPHERIC FLOW INFLUENCES
THE REGION...SWLY SFC WINDS OF 20-25 MPH WITH HIGHER GUSTS ARE
EXPECTED WHILE DIURNALLY DEEPENING BOUNDARY-LAYER CIRCULATIONS ALLOW
THE STRONGER FLOW ALOFT TO BECOME MANIFESTED AT THE SFC. THE
STRONG-WIND POTENTIAL WILL BE AIDED BY A TIGHTENING SFC PRESSURE
GRADIENT IN MANY AREAS.

SOME MODEL GUIDANCE SUGGESTS THAT A RELATIVE MINIMUM IN SFC WIND
SPEEDS MAY OCCUR ACROSS PARTS OF CNTRL/N-CNTRL NM IN THE VICINITY OF
A WEAKER LOWER-LEVEL PRESSURE GRADIENT. THIS MAY PREVENT SUSTAINED
WIND SPEEDS FROM BECOMING CRITICALLY STRONG WITHIN THIS AREA.
HOWEVER...FORECAST SOUNDINGS INDICATE MIXED-LAYER HEIGHTS REACHING
OVER 11 KFT ACROSS CNTRL/N-CNTRL NM...ALLOWING EVEN STRONGER
MID-LEVEL FLOW -- I.E. AROUND THE 500-MB LEVEL -- TO BE MANIFESTED
AT THE SFC AS FREQUENT GUSTS OF 25 TO 30 MPH. AND...WITH VERY LOW RH
VALUES EXPECTED IN THIS AREA AMIDST VERY DRY FUELS AND A WARM/HOT
AIR MASS -- AS DISCUSSED BELOW -- CRITICAL DESIGNATION IS WARRANTED
DESPITE THE LOCALIZED WEAKER SFC WINDS.

----RELATIVE HUMIDITY VALUES AND TEMPERATURES----
WITH AN ANTECEDENTLY DRY AIR MASS...AND DOWNSLOPE EFFECTS AIDING
BOUNDARY-LAYER WARMING/DRYING...RH VALUES ARE EXPECTED TO FALL TO
BETWEEN 4 AND 13 PERCENT DURING THE AFTERNOON IN MOST AREAS AS
VERTICAL MIXING STRENGTHENS. THIS WILL OCCUR AS TEMPERATURES RISE
INTO THE 80S AND 90S IN MOST LOCATIONS.

----FUELS----
FUELS ARE DRY TO VERY DRY ACROSS MUCH OF THE AREA WITH ONGOING
DROUGHT CONDITIONS IN PLACE. THESE DRY/VERY FUELS WILL EXACERBATE
THE FIRE WEATHER THREAT...EVEN IN AREAS WHERE SUSTAINED SFC WINDS
ONLY APPROACH MARGINALLY CRITICAL THRESHOLDS. ACROSS PARTS OF THE
CNTRL/SRN ROCKIES...SOME AREAS HAVE RECEIVED WETTING RAINS
ASSOCIATED WITH THUNDERSTORM ACTIVITY. HOWEVER...MANY AREAS DID NOT
RECEIVE APPRECIABLE RAINFALL...YIELDING BELOW-NORMAL PRECIPITATION
TO SUPPORT DRY FUELS.

...THE FOLLOWING LOCATIONS IN SRN CA----MUCH OF THE ERN TWO-THIRDS
OF SANTA BARBARA COUNTY...THE NRN TWO-THIRDS OF VENTURA
COUNTY...NWRN/N-CNTRL LOS ANGELES COUNTY...PARTS OF FAR SRN KERN
COUNTY...
UPON COORDINATION WITH THE OXNARD CA AND HANFORD CA WEATHER FORECAST
OFFICES...THE AREA HAS BEEN UPGRADED TO CRITICAL DESIGNATION.

----SYNOPTIC/MESOSCALE OVERVIEW----
SUBSIDENT FLOW ALOFT BEHIND THE NEGATIVELY TILTED SHORTWAVE TROUGH
WILL ALLOW FOR MODEST EWD TRANSLATION OF THE MEAN CENTER OF A SFC
ANTICYCLONE POSITIONED OVER THE PACIFIC HIGH SEAS. THIS SUBSIDENT
FLOW ALOFT WILL EXTEND A RIDGE AXIS EMANATING FROM THE ANTICYCLONE
CENTER ENEWD INTO PARTS OF THE NWRN CONUS. AND...WITH A
STRENGTHENING LOW-LEVEL THERMAL RIDGE ORIENTED N-S OVER THE LOWER CO
RIVER VALLEY...THE SFC PRESSURE GRADIENT WILL TIGHTEN ACROSS THE
AREA. THIS WILL ACCELERATE FLOW ALONG THE LONG AXIS OF THE SAN
JOAQUIN VALLEY...WITH NWLY TO NELY WINDS STRENGTHENING ACROSS THE
COASTAL RANGES AND ADJACENT FOOTHILLS DURING THE AFTERNOON...AND
ESPECIALLY DURING THE EVENING AND OVERNIGHT HOURS. THIS REGIME IS
EXPECTED TO SUPPORT A STRENGTHENING OFFSHORE FLOW COMPONENT ALONG
PARTS OF THE SANTA BARBARA COUNTY AND FAR WRN VENTURA COUNTY COASTS
AFTER THE FLOW DESCENDS IN THE LEE OF THE SANTA YNEZ MOUNTAINS. THE
EFFECTS OF SUBSIDENCE WITHIN THE LARGE-SCALE SYNOPTIC FLOW REGIME
WILL BE AUGMENTED BY DOWNSLOPE EFFECTS YIELDING BOUNDARY-LAYER
WARMING/DRYING.

----WINDS----
NWLY TO NELY SFC WINDS ARE EXPECTED TO INCREASE TO 20-30 MPH WITH
GUSTS REACHING 35-45 MPH. THE STRONGEST OF THESE WINDS WILL OCCUR ON
A LOCALIZED BASIS THROUGH FAVORED PASSES AND CANYONS. CRITICALLY
STRONG WINDS WILL BECOME INCREASINGLY LIKELY DURING THE
AFTERNOON...AND WILL BE ESPECIALLY LIKELY DURING THE EVENING AND
OVERNIGHT HOURS. FOUR-KM NAM GUIDANCE AFFIRMS THE ANTICIPATION OF
THIS LOCALIZED/TERRAIN-ENHANCED FLOW REGIME...WITH EVEN SOME
SUGGESTION OF ENHANCED WINDS BY COARSER-RESOLUTION MODEL GUIDANCE.

----RELATIVE HUMIDITY VALUES AND TEMPERATURES----
AFTER RH VALUES FALL INTO THE UPPER SINGLE DIGITS TO MIDDLE TEENS
DURING THE DAY ON WEDNESDAY...THE STRENGTHENING DOWNSLOPE FLOW
COMPONENT AND DECREASING PW WILL KEEP RH VALUES CRITICALLY LOW INTO
THE OVERNIGHT HOURS WED NIGHT IN MANY AREAS AS TEMPERATURES ONLY
FALL INTO THE 60S AND 70S.

----FUELS----
FUELS ARE VERY DRY ACROSS THE AREA...WITH SEVERE DROUGHT CONDITIONS
IN PLACE AND BELOW-NORMAL PRECIPITATION DURING THE PAST FEW MONTHS.
CURRENT FUEL DRYNESS IS REPRESENTATIVE OF FUEL DRYNESS
CHARACTERISTIC OF SEPTEMBER PER THE LATEST SOUTHERN CALIFORNIA GACC
GUIDANCE. GIVEN THE STATE OF THE FUELS...THE AFOREMENTIONED STRONG
WIND/LOW RH THREAT WILL EXACERBATE THE FIRE WEATHER THREAT AND
WARRANT CRITICAL DESIGNATION.

...SURROUNDING THE ERN CRITICAL AREA ACROSS PORTIONS OF
NV...CNTRL/SRN AZ...SWRN/S-CNTRL NM...CNTRL/N-CNTRL/ERN CO...SRN
WY...THE NWRN HALF OF UT...
MANY AREAS W OF A CNTRL/SRN-HIGH-PLAINS LEE TROUGH WILL EXPERIENCE
CRITICALLY LOW RH WITHIN A DRY AIR MASS AMIDST DIURNALLY
STRENGTHENING VERTICAL MIXING. HOWEVER...IN THE ABSENCE OF STRONGER
LOW/MID-LEVEL FLOW IN MANY AREAS...CRITICALLY STRONG SUSTAINED WIND
SPEEDS WILL BE UNLIKELY IN COMBINATION WITH THESE LOW RH VALUES.
EXCEPTIONS ARE ACROSS PORTIONS OF CNTRL/N-CNTRL CO INTO SRN WY WHERE
CRITICAL METEOROLOGICAL CONDITIONS MAY ENSUE. HOWEVER...MORE LIMITED
FUEL DRYNESS IN THESE AREAS MAY MITIGATE THE FIRE WEATHER
THREAT...AND RELATIVELY LOWER TEMPERATURES AND HIGHER RH ACROSS
PARTS OF CNTRL/N-CNTRL CO MAY MITIGATE THE FIRE WEATHER THREAT.

...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...