Front Range Foothills / Denver Metro Weather Briefing – 21 June 2012 – 0700 hrs MDT

Synopsis: Today will be the last day of temps in the 80’s in the metro before we move into a long period of temps in the 90’s and low RH. Temperature wise looks like Saturday will be the hottest with afternoon high temps of near 100 degrees. The foothills will remain in the 80’s.

For this afternoon, expect gusty winds of up to 30 mph to develop for both the metro and foothills.

For Friday in the foothills, warmer and drier conditions will prevail with increasing winds over the mountains, foothills and mountain valleys by the afternoon. This will result in the potential for critical fire weather conditions. Anticipate a Red Flag Warning for the Front Range above 6000 on Friday.


Watches & Warnings:

A Fire Weather Watch is in effect for Friday for the Front Range westward.

* Timing...the gusty winds and low humidity are expected to develop by noon Friday and continuing Friday evening.

* Winds...Southwest 15 to 25 mph with gusts up to 35 mph.

* Relative humidity...In the single digits.

* Impacts...the increasing winds...combined with the warm and dry conditions could create extreme fire behavior on already existing fires and make any new ignitions difficult to control with possible high rates of spread.




Hazardous Weather Outlook for Today: It will remain dry through tonight with only an isolated late afternoon or early evening thunderstorm possible over the higher terrain south of I-70. Temperatures will warm back into the 80s across the plains with gusty southeast winds by afternoon.

For Friday through Wednesday: Dry conditions are expected to continue through the first half of next week with the chances for any afternoon thunderstorms remaining low. A strong upper level ridge building over the state will bring hot temperatures back to the region Friday and continue through the weekend. Some locations on the plains may reach the century mark Friday, Saturday and Sunday. Along with the near record temperatures, relative humidities will also be very low, keeping volatile fire conditions in the mountains and foothills through the middle of next week.




Front Range Foothills Forecast

Today: Sunny, with a high near 79. South wind at 9 mph becoming east. Winds could gust as high as 15 mph.

Tonight: Partly cloudy, with a low around 53. Calm wind becoming west southwest between 7 and 10 mph. Winds could gust as high as 17 mph.

Friday: Sunny, with a high near 88. Southwest wind between 6 and 10 mph, with gusts as high as 16 mph.

Friday Night: Mostly clear, with a low around 55. West wind between 6 and 11 mph, with gusts as high as 17 mph.

Saturday: Sunny, with a high near 88. Southwest wind between 5 and 10 mph, with gusts as high as 16 mph.

West Denver Metro Forecast

Today: Sunny, with a high near 83. South southeast wind between 7 and 13 mph, with gusts as high as 20 mph.

Tonight: Mostly clear, with a low around 57. Southeast wind between 10 and 13 mph becoming light. Winds could gust as high as 20 mph.

Friday: Sunny, with a high near 95. Southwest wind between 3 and 7 mph.

Friday Night: Mostly clear, with a low around 62. Calm wind becoming west southwest between 7 and 10 mph.

Saturday: Sunny and hot, with a high near 99. West southwest wind at 10 mph becoming south southeast.


Fire Weather for Zone 239 (Below 6000 feet) –

Today...


Sky/weather.........partly cloudy (35-45%) until 0900...then mostly sunny.

Max temperature.....82-86.
24 hr trend......7-10 degrees warmer.

Min humidity........22-26%.
24 hr trend......7-10% drier.

20-foot winds.......southeast 10-16 mph with gusts to 30 mph.

Haines index........2 very low.

LAL.................1.

CWR.................0 percent.

10k ft free winds...west 25-35 mph.

Mixing height.......below 1000 ft agl until 0700...then 6000-7000 ft agl.

Transport winds.....south 10-15 mph.

Smoke dispersal.....poor until 0900...then fair.


Tonight...


Sky/weather.........mostly clear.

Min temperature.....56-60.
24 hr trend......7-10 degrees warmer.

Max humidity........55-65%.
24 hr trend......15-20% drier.

20-foot winds.......south 9-15 mph with gusts to 30 mph.

Haines index........4 low.

LAL.................1.

CWR.................0 percent.

10k ft free winds...west 20-30 mph.

Mixing height.......5000 ft agl until 2400...then below 1000 ft agl.

Transport winds.....south 10-15 mph.

Smoke dispersal.....poor.


Friday...


Sky/weather.........mostly sunny.

Max temperature.....94-98.
24 hr trend......10-15 degrees warmer.

Min humidity........9-13%.
24 hr trend......10-15% drier.

20-foot winds.......variable less than 8 mph.

Haines index........5 moderate.

LAL.................1.

CWR.................0 percent.

10k ft free winds...southwest 25-35 mph.

Mixing height.......below 1000 ft agl until 0800. 15000-16000 ft agl after 1100.

Transport winds.....light and variable until 1100. Southwest around 20 mph after 1500.

Smoke dispersal.....poor until 1100. Excellent after 1500.


Fire Weather Zone 216 (Above 6000 Feet)


Today...


Sky/weather.........mostly cloudy (50-60%) until 0900...then partly cloudy (30-35%) until 1200...then mostly sunny until 1500...then partly cloudy. Isolated thunderstorms after 1500.

Max temperature.....76-82.
24 hr trend......15-20 degrees warmer.

Min humidity........18-24%.
24 hr trend......2-4% drier.

20-foot winds.......
Valleys / lower slopes...upslope / upvalley 4-10 mph becoming southeast 8-13 mph in the afternoon. Gusts up to 25 mph.
ridges/upr slopes....southeast 8-13 mph. Gusts up to 20 mph increasing to 30 mph in the afternoon.

Haines index........3 very low.

LAL.................1 until 1500...then 2.

CWR.................0 percent.

10k ft free winds...west 25-35 mph.

Mixing height.......10500-11500 ft agl.

Transport winds.....southwest 10-15 mph.

Smoke dispersal.....poor until 1000...then good.


Tonight...


Sky/weather.........mostly clear. Isolated thunderstorms until 2100.

Min temperature.....50-56.
24 hr trend......7-10 degrees warmer.

Max humidity........48-58%.
24 hr trend......25-35% drier.

20-foot winds.......
Valleys / lower slopes...southwest 8-14 mph with gusts to 25 mph.
Ridges / upper slopes....southwest 9-15 mph with gusts to 30 mph.

Haines index........4 low.

LAL.................2 until 2100...then 1.

CWR.................0 percent.

10k ft free winds...west 20-30 mph.

Mixing height.......9500 ft agl until 2400...then 1000 ft agl.

Transport winds.....southwest around 10 mph.

Smoke dispersal.....poor.


Friday...


Sky/weather.........mostly sunny.

Max temperature.....83-93.
24 hr trend......4-7 degrees warmer.

Min humidity........9-13%.
24 hr trend......10-15% drier.

20-foot winds.......
Valleys / lower slopes...southwest 9-15 mph with gusts to 25 mph.
Ridges / upper slopes....southwest 11-17 mph with gusts to 25 mph.

Haines index........4 low.

LAL.................1.

CWR.................0 percent.

10k ft free winds...southwest 25-35 mph.

Mixing height.......below 1000 ft agl until 0700. 16000-17000 ft agl after 1200.

Transport winds.....southwest 15-20 mph until 1300...then around 25 mph.

Smoke dispersal.....poor until 0900. Excellent after 1200.



Other notable Colorado weather:

From Central and Western Colorado to California – Red Flag Warnings and Fire Weather Watches are in effect for Friday.

Front Range Foothills / West Denver Metro Weather Briefing – 21 June 2012 – 1930 hrs MDT

Synopsis: Hot, dry and breezy conditions Friday afternoon through Saturday as high pressure will bring hot and dry air over Colorado on Friday and Saturday. Meanwhile a weak upper level disturbance passing north of Colorado will increase the winds on Friday. This combination will create very high to extreme fire danger in and near the northern Colorado mountains. It will remain warm and dry Friday night with poor humidity recovery in many mountain areas. Saturday will see near record heat with very low humidities although winds are expected to be lighter.


Watches & Warnings:



Red Flag Warnings are in effect for everyone BUT JeffCo below 6000 feet….go figure. Does West Metro have a new prototype wildland shield.

* Timing...Winds will increase on Friday afternoon with near record heat and very low humidities. Conditions will ease a little on Friday evening though it will still be warm and dry Friday night with near record heat again on Saturday.

* Winds...South 10 to 20 mph with gusts up to 35 mph.

* Relative Humidity...as low as 12 percent.

* Impacts...The increasing winds, combined with the warm and dry conditions will make it easy for new fires to start and make any new ignitions difficult to control with possible high rates of spread.

Hazardous Weather Outlook for Friday through Wednesday: Dry weather is expected over the forecast area through the weekend. The slight chance of late day showers and thunderstorms will return Monday through next Wednesday. Temperatures will be hot Friday through Sunday, with readings well above seasonal normals. With all the heat and dry conditions expected, there will be a significant risk of wild fire starts.


Front Range Foothills Forecast

Tonight: Mostly clear, with a low around 53. East wind at 7 mph becoming west.

Friday: Sunny, with a high near 89. West wind 6 to 10 mph becoming south. Winds could gust as high as 17 mph.

Friday Night: Mostly clear, with a low around 56. Breezy, with a west wind between 8 and 17 mph, with gusts as high as 29 mph.

Saturday: Sunny, with a high near 89. Breezy, with a west wind 7 to 17 mph becoming east southeast. Winds could gust as high as 28 mph.

Saturday Night: Mostly clear, with a low around 58. North northwest wind between 3 and 10 mph.

Sunday: A 20 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 85.

West Denver Metro Forecast

Tonight: Mostly clear, with a low around 57. Southwest wind between 3 and 10 mph, with gusts as high as 15 mph.

Friday: Sunny, with a high near 95. West southwest wind at 10 mph becoming south southeast. Winds could gust as high as 16 mph.

Friday Night: Mostly clear, with a low around 63. West southwest wind between 3 and 11 mph.

Saturday: Sunny and hot, with a high near 100. West southwest wind 5 to 10 mph becoming southeast.

Saturday Night: Mostly clear, with a low around 66. North northwest wind between 5 and 9 mph.

Sunday: Mostly sunny, with a high near 96.