Day 3-8 Fire Weather Forecast Issued on Apr 29, 2013

Updated: Mon Apr 29 20:07:03 UTC 2013

Day 3-8 Fire Weather Forecast Graphic Issued on Apr 29, 2013
 
Day 3 Probabilistic Dry Thunder/Strong Wind FireWX Forecast Graphic Issued on Apr 29, 2013

Day 3 Experimental Probabilistic Fire Weather Outlooks:
Probability of dry thunderstorms with dry fuels within 12 miles of a point denoted by scalloped lines for
- Critical Area - 40% (blue)
- Marginal Area - 10% (brown)
Probability of strong winds, low RH, and warm temperatures concurrent for at least 3 hours with dry fuels within 12 miles of a point denoted by solid lines for
- Critical Area - 70% (red)
- Marginal Area - 40% (orange)


Day 4 Probabilistic Dry Thunder/Strong Wind FireWX Forecast Graphic Issued on Apr 29, 2013

Day 4 Experimental Probabilistic Fire Weather Outlooks:
Probability of dry thunderstorms with dry fuels within 12 miles of a point denoted by scalloped lines for
- Critical Area - 40% (blue)
- Marginal Area - 10% (brown)
Probability of strong winds, low RH, and warm temperatures concurrent for at least 3 hours with dry fuels within 12 miles of a point denoted by solid lines for
- Critical Area - 70% (red)
- Marginal Area - 40% (orange)


Day 5 Probabilistic Dry Thunder/Strong Wind FireWX Forecast Graphic Issued on Apr 29, 2013

Day 5 Experimental Probabilistic Fire Weather Outlooks:
Probability of dry thunderstorms with dry fuels within 12 miles of a point denoted by scalloped lines for
- Critical Area - 40% (blue)
- Marginal Area - 10% (brown)
Probability of strong winds, low RH, and warm temperatures concurrent for at least 3 hours with dry fuels within 12 miles of a point denoted by solid lines for
- Critical Area - 70% (red)
- Marginal Area - 40% (orange)


Day 6 Probabilistic Dry Thunder/Strong Wind FireWX Forecast Graphic Issued on Apr 29, 2013

Day 6 Experimental Probabilistic Fire Weather Outlooks:
Probability of dry thunderstorms with dry fuels within 12 miles of a point denoted by scalloped lines for
- Critical Area - 40% (blue)
- Marginal Area - 10% (brown)
Probability of strong winds, low RH, and warm temperatures concurrent for at least 3 hours with dry fuels within 12 miles of a point denoted by solid lines for
- Critical Area - 70% (red)
- Marginal Area - 40% (orange)


Day 7 Probabilistic Dry Thunder/Strong Wind FireWX Forecast Graphic Issued on Apr 29, 2013

Day 7 Experimental Probabilistic Fire Weather Outlooks:
Probability of dry thunderstorms with dry fuels within 12 miles of a point denoted by scalloped lines for
- Critical Area - 40% (blue)
- Marginal Area - 10% (brown)
Probability of strong winds, low RH, and warm temperatures concurrent for at least 3 hours with dry fuels within 12 miles of a point denoted by solid lines for
- Critical Area - 70% (red)
- Marginal Area - 40% (orange)


Day 8 Probabilistic Dry Thunder/Strong Wind FireWX Forecast Graphic Issued on Apr 29, 2013

Day 8 Experimental Probabilistic Fire Weather Outlooks:
Probability of dry thunderstorms with dry fuels within 12 miles of a point denoted by scalloped lines for
- Critical Area - 40% (blue)
- Marginal Area - 10% (brown)
Probability of strong winds, low RH, and warm temperatures concurrent for at least 3 hours with dry fuels within 12 miles of a point denoted by solid lines for
- Critical Area - 70% (red)
- Marginal Area - 40% (orange)


Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
D3 50,596 3,762,131 Las Vegas, NV...Henderson, NV...N. Las Vegas, NV...Santa Clarita, CA...Lancaster, CA...
D4 8,750 1,784,898 Glendale, CA...Santa Clarita, CA...Lancaster, CA...Palmdale, CA...Victorville, CA...
D3Wed, May 01, 2013 - Thu, May 02, 2013 D6Sat, May 04, 2013 - Sun, May 05, 2013
D4Thu, May 02, 2013 - Fri, May 03, 2013 D7Sun, May 05, 2013 - Mon, May 06, 2013
D5Fri, May 03, 2013 - Sat, May 04, 2013 D8Mon, May 06, 2013 - Tue, May 07, 2013
(All days are valid from 12 UTC - 12 UTC)
   ZCZC SPCFWDD38 ALL
   FNUS28 KWNS 292005
   
   DAY 3-8 FIRE WEATHER OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0305 PM CDT MON APR 29 2013
   
   VALID 011200Z - 071200Z
   
   MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH ABOUT DAY
   5/FRI OF THE EXTENDED PERIOD. A DEEPENING TROUGH OVER THE NRN
   ROCKIES INTO THE FOUR CORNERS AREA WILL SHIFT EWD THROUGH DAY 4/THU
   BEFORE CLOSING OFF OVER THE SOUTHERN PLAINS. AT THE SFC...STRONG
   WINDS WILL DEVELOP IN RESPONSE TO A TIGHT PRESSURE GRADIENT
   EXTENDING ROUGHLY FROM W TO E ACROSS EASTERN CA INTO THE GREAT
   BASIN...AND ELEVATED TO CRITICAL CONDITIONS ARE EXPECTED DAY
   3-4/WED-THU. BY DAY 5/FRI NIGHT...MODEL DIFFERENCE START TO BECOME
   LARGE IN THE PLACEMENT OF THE UPPER LOW...WITH THE GFS BEING MORE
   PROGRESSIVE AND CONTINUING TO SLOWLY SHIFT GENERALLY EWD THROUGH THE
   END OF THE PERIOD. THE ECMWF ON THE OTHER HAND MAINTAINS UPPER
   ANTICYCLONE OVER THE EASTERN U.S...BLOCKING EWD PROGRESSION OF UPPER
   LOW AND FORCING IT NORTHWARD TOWARD THE UPPER MIDWEST/GREAT LAKES BY
   EARLY NEXT WEEK. BOTH MODELS DO INDICATE THAT A SECONDARY SHORTWAVE
   TROUGH WILL DEVELOP ON THE BACKSIDE OF THE PLAINS/MIDWEST UPPER LOW
   AND DEVELOP WESTWARD WITH TIME OVER THE WEEKEND/EARLY NEXT WEEK. THE
   INTENSITY AND PLACEMENT OF THIS FEATURE VARIES GREATLY HOWEVER AND
   CONFIDENCE BECOMES LOW FROM LATE DAY 5/FRI NIGHT THROUGH THE END OF
   THE FORECAST PERIOD.
   
   ...DAY 3/WED - SRN CA/SRN NV/FAR NW AZ...
   STRONG SFC HEATING IS EXPECTED AS THERMAL RIDGE EXPANDS NORTHWARD
   ACROSS MUCH OF THE SOUTHWESTERN STATES. HIGH PRESSURE SINKING
   SOUTHWARD FROM THE INTERMOUNTAIN WEST TOWARD THE GREAT BASIN WILL
   CREATE A TIGHT SFC PRESSURE GRADIENT OVER THE REGION. IN
   RESPONSE...STRONG N TO NE WINDS ARE EXPECTED OVER MUCH OF THE CA
   DESERTS INTO SRN NV AND THE PARTS OF THE LOWER CO VALLEY...WITH
   MODERATE OFFSHORE WINDS OVER THE SOUTHWEST CA MOUNTAINS NORTH OF
   SGX. WIND SPEEDS ACROSS THE CRITICAL AREA FROM 20-30 MPH WITH GUSTS
   TO 40 MPH ARE EXPECTED. HIGHER WIND SPEEDS ARE POSSIBLE THROUGH
   FAVORED CANYONS AND PASSES OF SOUTHWEST CA. WITH WARM TEMPERATURES
   AND DEEP BOUNDARY LAYER MIXING WILL COME LOW RH VALUES FROM THE
   MIDDLE SINGLE DIGITS TO AROUND 10 PERCENT...CREATING CRITICAL FIRE
   WEATHER CONDITIONS.
   
   SURROUNDING THE CRITICAL...MORE MARGINAL CONDITIONS ARE EXPECTED
   WHERE WIND SPEEDS WILL BE SLIGHTLY LOWER.
   
   ...DAY 4/THU - SRN CA/FAR SRN NV/SRN NV...
   A COLD FRONT WILL SINK SOUTH AND EAST ACROSS THE DESERT SOUTHWEST
   WEDNESDAY NIGHT AND WINDS WILL SHIFT TO THE N/NE BY THURSDAY
   MORNING. AS STRONG HIGH PRESSURE CONTINUES TO DEVELOP S AND E ACROSS
   THE EASTERN GREAT BASIN AND ROCKIES...THE PRESSURE GRADIENT ACROSS
   THE SOUTHWEST STATES WILL BECOME MORE NW-SE ORIENTED AND PUSH
   FURTHER SOUTH FROM SRN CA ACROSS CENTRAL INTO SE AZ. THIS PRESSURE
   GRADIENT IS EXPECTED TO WEAKEN SOME DURING THE AFTERNOON AND
   OVERNIGHT HOURS. HOWEVER...THIS SETUP WILL ALLOW MODERATE OFFSHORE
   WINDS TO CONTINUE ACROSS PARTS OF SRN CA...AND ANOTHER DAY OF
   CRITICAL CONDITIONS ARE EXPECTED AS RH VALUES REMAIN IN THE SINGLE
   DIGITS TO LOW TEENS. 
   
   ADDITIONALLY...BREEZY CONDITIONS WILL PERSIST ACROSS FAR SRN CA INTO
   THE AZ DESERTS WHERE WARM AND DRY CONDITIONS ARE EXPECTED.
   CONDITIONS HERE WILL BE SOMEWHAT MORE MARGINAL WITH LIGHTER WIND
   SPEEDS EXPECTED AS PRESSURE GRADIENT BEGINS TO WEAKEN OVER THIS
   AREA.
   
   ..LEITMAN.. 04/29/2013
   
   ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
   
   $$

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