|Moist - Little or no risk for large fires.|
|Dry - Low risk of large fires in the absence of a "High Risk" event.|
|Very dry - Low/Moderate risk of large fires in the absence of a "High Risk" event.|
High Risk Events
|Wind - strong winds combined with low RH (below 15%)|
|Dry lightning or any lightning during very hot, dry weather.|
Western Great Basin Area 7 Day
Significant Fire Potential
Issued: Tuesday, Jul 22, 2014 Parameters:
|Predictive Service Area||
|WB01 - Northwest||
|WB02 - Northern Mtns.|
|WB03 - Sierra Front|
|WB04 - West Central Mtns.||
|WB05 - Central Mountains||
|WB06 - Humboldt Basin|
|WB07 - Northeast||
|WB08 - West Desert|
|WB09 - East Central Mtns.||
|WB10 - Southeast Desert|
|WB11 - Southern Mtns.|
|WB12 - Southeast Mtns.|
|WB13 - East Desert||
Drier fast moving thunderstorms today over western/northwest NV with gusty outflow winds with MODERATE large fire potential especially in the PJ and areas that have not received much rainfall recently.
Gusty winds and much lower RH through Wednesday will increase fire potential.
An upper level disturbance near the SFO area will lift northeast into OR tonight. There is already lightning near this feature this morning, with instability increasing in western/northwest/northern NV this afternoon and evening. Any storms that develop will be very fast moving with a higher potential for drier lightning strikes, although storms redeveloping and moving over the same areas is also possible producing rainfall in some areas. The main question is the amount of lightning coverage due to morning cloud cover, and how much the fuels have moistened up with recent rainfall and higher RH. Gusty outflow winds 40-60 mph are still expected near thunderstorms.
A trough of low pressure has settled in off the CA coast with drier southwest flow developing across the eastern half of the WGB today. Drier air continues to spread across all areas of the WGB Wednesday through this weekend in most areas with drier weather lowering RH. SW winds increase today-Wednesday with RH 6-12%. High risk is forecast today for gusty winds and low RH across parts of central and eastern/northeast NV on existing fires and for the potential for holdovers from recent lightning and over western/northwest NV on Wednesday after lightning.
High pressure in the southwest will start to build west again later this week and through this weekend with temperatures increasing to above normal again and decreasing winds. This will provide an extended period of drying for the WGB after the recent wet weather. Monsoon moisture may start returning to far southern NV as early as later this week and this weekend, however a push north of thunderstorms is most likely Sunday into early next week. returning from south to north by early next week.
SEE OUR MULTIMEDIA FIRE WEATHER BRIEFING AT: http://gacc.nifc.gov/wgbc/predictive/outlooks/briefing/briefing.html
SEE OUR DAY1 / DAY2 HEAT INDEX:
MODERATE fire potential today over central/eastern/northeast NV through Wednesday due to gusty winds and much lower RH after recent lightning with a HIGH fire spread potential on exisiting fires. MODERATE fire potential over western and northwest NV today due to drier lightning and gusty outflow winds and Wednesday due to much lower RH and gusty winds. Even though thunderstorms have brought rainfall recently, not all areas received significant precipitation, and the PJ and timber areas will be slow to respond to the increase in moisture.
Severe to Exceptional Drought Continues Across the WGB: http://droughtmonitor.unl.edu/Home/RegionalDroughtMonitor.aspx?west
The main areas of concern will be in the very dry higher elevations where larger fuel moistures are very low and stricken by long term drought, and if there are ignitions in the right areas of the lower elevations where there is some grass to carry fire and fuel moistures are lower.
100-hr fuel moisture has increased to above normal in all areas, except the Sierra Front into western NV where fuel moisture is still below normal. ERCs have dropped to near to below normal in most areas, however ERCs are still above normal along the Sierra Front into western NV, but have now dropped to near the 80th percentile. Live fuel moisture dropped significantly over western/northwest areas due to the last period of heat, with some areas at/near critical levels. Recent rainfall and higher RH will mitigate some of the fuel concerns and provide a reprieve in some of the fine fuels, however still very dry conditions may exist in the larger fuels at mid-high elevations. Drought stress is ongoing across the landscape making fuels more critical in many areas, especially in Pinyon-Juniper and timber areas and over western and northern areas. Fuel moisture will be increasing across the WGB in areas that receive rainfall through early next week.
SEE THE NATIONAL FIRE POTENTIAL MAP AT: http://psgeodata.fs.fed.us/staticmap.html
SEE A 7-DAY PROJECTION OF ERC, F100 AND F1000:
Western Great Basin Area Preparedness Level is 2: LIGHT to possibly MODERATE IA expected today over western/northwest NV then LIGHT IA later this week through this weekend with breezy/dry weather. Anticipate LOW-MODERATE demand for outside of area resources through Wednesday.
National Preparedness Level is 3: HIGH demand for resources in support of other geographic areas.
SEE THE MORNING REPORT AT:
Forecasters: McGuire 7/22/2014 0954 MDT