Christman Field Latest Observations
Date Time
MST
Temp
°F
RH
%
DewPt
°F
Wind
mph
Dir
°
Gust
mph
Dir
°
Press
in Hg
Solar
W/m^2
Prec
in
2019-11-12 06:20 11.0 91.4 9.0 4.6 151 6.0 173 24.995 0.0 0.00
2019-11-12 06:15 10.5 90.1 8.2 5.3 173 6.3 173 24.992 0.0 0.00
2019-11-12 06:10 10.7 91.2 8.6 5.2 164 6.5 161 24.993 0.0 0.00
2019-11-12 06:05 10.0 90.4 7.7 3.8 158 5.9 160 24.991 0.0 0.00
2019-11-12 06:00 9.8 88.6 7.2 0.7 166 3.2 166 24.991 0.0 0.00
2019-11-12 05:55 10.1 89.3 7.6 0.3 240 1.7 333 24.992 0.0 0.00
2019-11-12 05:50 11.6 86.3 8.3 0.7 352 2.1 352 24.993 0.0 0.00
2019-11-12 05:45 13.2 88.8 10.5 0.5 352 1.5 352 24.994 0.0 0.00
2019-11-12 05:40 13.0 92.0 11.1 0.5 352 1.6 351 24.995 0.0 0.00
2019-11-12 05:35 11.9 92.8 10.2 1.1 351 2.5 352 24.995 0.0 0.00
2019-11-12 05:30 9.8 91.6 7.9 3.1 352 4.5 340 24.996 0.0 0.00
2019-11-12 05:25 8.8 89.4 6.3 3.2 340 3.8 348 24.996 0.0 0.00
2019-11-12 05:20 11.5 84.2 7.6 3.2 5 4.2 5 24.999 0.0 0.00
2019-11-12 05:15 12.1 92.6 10.3 0.3 323 2.1 322 24.999 0.0 0.00
2019-11-12 05:10 10.8 93.8 9.4 0.2 236 1.8 236 25.002 0.0 0.00
2019-11-12 05:05 10.5 93.0 8.9 0.5 290 1.1 290 25.006 0.0 0.00
2019-11-12 05:00 9.2 91.8 7.3 1.2 290 2.0 290 25.012 0.0 0.00
2019-11-12 04:55 8.9 90.4 6.6 2.2 290 4.6 296 25.015 0.0 0.00
2019-11-12 04:50 8.2 92.4 6.5 1.3 295 4.9 299 25.017 0.0 0.00
2019-11-12 04:45 6.3 89.2 3.8 0.5 168 1.7 168 25.020 0.0 0.00
2019-11-12 04:40 7.5 87.4 4.5 1.1 168 2.0 168 25.021 0.0 0.00
2019-11-12 04:35 8.1 88.4 5.3 1.9 105 3.5 25 25.023 0.0 0.00
2019-11-12 04:30 9.4 87.4 6.4 1.2 25 3.0 25 25.024 0.0 0.00
2019-11-12 04:25 10.2 91.8 8.3 0.7 171 1.6 171 25.021 0.0 0.00
2019-11-12 04:20 9.2 90.9 7.1 0.5 171 1.6 171 25.023 0.0 0.00
2019-11-12 04:15 9.3 90.9 7.2 1.2 170 3.4 170 25.032 0.0 0.00
2019-11-12 04:10 7.8 92.7 6.1 1.3 231 3.2 231 25.037 0.0 0.00
2019-11-12 04:05 7.2 88.6 4.6 1.2 231 3.2 231 25.040 0.0 0.00
2019-11-12 04:00 7.9 91.1 5.8 0.4 22 1.5 22 25.032 0.0 0.00
2019-11-12 03:55 7.9 90.0 5.5 1.5 22 2.1 22 25.032 0.0 0.00
CIRA

Cooperative Institute for Research in the Atmosphere

Dr. John A. Knaff

Job Title:
Research Meteorologist
Phone Number:

970-491-8881

Fax Number:

970-491-8241

Mailing Addresss:
John Knaff
NESDIS/STAR – RAMMB
CIRA/Colorado State University
Campus Delivery 1375
Fort Collins, CO 80523-1375
Office Location:
CIRA Room 45
About Me:

John Knaff earned a B.S. in Meteorology (1989) from Texas A&M University, and a MS (1992) and PhD (1997) in Atmospheric Science from Colorado State University. He was briefly a post-doctoral researcher in the Department of Atmospheric Science at Colorado State University (1997). Following that appointment, he was a post-doctoral Fellow at the Cooperative Institute for Research in the Atmosphere at Colorado State University (1997-1999) where he was also employed as a Research Scientist position (1999-2006). He joined NOAA in 2006 as a Meteorologist in the NESDIS Regional and Mesoscale Meteorology Branch located in Fort Collins, Colorado.

As a student, he concentrated on topics related to tropical climate variability including El Nino/Southern Oscillation, monsoons, tropical cyclones and large-scale Atlantic climatology. The focus of his more recent studies, including his postdoctoral work, has been on observational aspects of hurricane structure and intensity variations and prediction. Much of that work has led to the development of forecast applications that have been transferred to operations at the NESDIS, the National Hurricane Center, the Joint Typhoon Warning Center, and tropical cyclone warning centers worldwide. These efforts have led to many awards. In 2004, he received the NOAA David Johnson Award for basic research for improving the understanding of tropical phenomenon and predicting tropical cyclone intensity, accompanied by exemplary transfer of the results into operational products. He has also been awarded Department of Commerce Bronze Medals in 2007, 2010, and 2012, was a member of a team that received the Colorado Governor’s Award for High Impact Research in 2012 and in 2014 was recognized for his support of JTWC operations.

Up-to-date publication information can be found at the following web locations:

http://www.researcherid.com/rid/F-5599-2010

http://orcid.org/0000-0003-0427-1409

    Publications

    Tropical Cyclone Heat Content in NOAA “State of the Climate in 2017”

    Published Date: 2017
    Published By: American Meteorological Society

    Proxy-visible Imagery

    Published Date: 2017
    Published By: Conference

    Proxy-visible Imagery

    Published Date: 2017
    Published By: Conference

    ATMS-MiRS: Tropical Cyclone Applications

    Published Date: 2017
    Published By: Conference

    Proxy-visible Imagery

    Published Date: 2018
    Published By: Conference

    ATMS – MiRS: Tropical Cyclone Applications

    Published Date: 2017
    Published By: Conference

    Proxy – Visible Imagery

    Published Date: 2017
    Published By: Conference

    Improvements to Operational Statistical Tropical Cyclone Intensity Forecast Models

    Published Date: 2018
    Published By: Conference

    Proxy Visible Satellite Imagery

    Published Date: 2018
    Published By: Conference

    Tropical Cyclone Gale Wind Radii Estimates for the Western North Pacific

    Published Date: 2017
    Published By: Weather and Forcasting

    Global assessment of tropical cyclone intensity statistical–dynamical hindcasts

    Published Date: 2017
    Published By: Royal Meteorological Society

    Forecasting Tropical Cyclone Eye Formation and Dissipation in Infrared Imagery

    Published Date: 2017
    Published By: Weather and Forcasting

    A Global Statistical–Dynamical Tropical Cyclone Wind Radii Forecast Scheme

    Published Date: 2017
    Published By: Weather and Forcasting

    On the Desirability and Feasibility of a Global Reanalysis of Tropical Cyclones

    Published Date: 2018
    Published By: American Meteorological Society

    Physical understanding of the tropical cyclone wind-pressure relationship

    Published Date: 2017
    Published By: Nature Communications

    Impact of Storm Size on Prediction of Storm Track and Intensity Using the 2016 Operational GFDL Hurricane Model

    Published Date: 2017
    Published By: Weather and Forcasting

    Hybrid variational-ensemble assimilation of lightning observations in a mesoscale mode

    Published Date: 2014
    Published By: Geoscientific Model Development

    Is Tropical Cyclone Intensity Guidance Improving?

    Published Date: 2014
    Published By: American Meteorological Society
    The mean absolute error of the official tropical cyclone (TC) intensity forecasts from the National Hurricane Center (NHC) and the Joint Typhoon Warning Center (JTWC) shows limited evidence of improvement over the past two decades. This result has sometimes erroneously been used to conclude that little or no progress has been made in the TC intensity guidance models. This article documents statistically significant improvements in operational TC intensity guidance over the past 24 years (1989–2012) in four tropical cyclone basins (Atlantic, eastern North Pacific, western North Pacific, and Southern Hemisphere). Errors from the best available model have decreased at 1%–2% yr−1 at 24–72 h, with faster improvement rates at 96 and 120 h. Although these rates are only about one-third to one-half of the rates of reduction of the track forecast models, most are statistically significant at the 95% level. These error reductions resulted from improvements in statistical–dynamical intensity models and consensus techniques that combine information from statistical–dynamical and dynamical models. The reason that the official NHC and JTWC intensity forecast errors have decreased slower than the guidance errors is because in the first half of the analyzed period, their subjective forecasts were more accurate than any of the available guidance. It is only in the last decade that the objective intensity guidance has become accurate enough to influence the NHC and JTWC forecast errors.

    An Objective Satellite-Based Tropical Cyclone Size Climatology

    Published Date: 2014
    Published By: Geoscientific Model Development

    Storm-centered infrared (IR) imagery of tropical cyclones (TCs) is related to the 850-hPa mean tangential wind at a radius of 500 km (V500) calculated from 6-hourly global numerical analyses for North Atlantic and eastern North Pacific TCs for 1995–2011. V500 estimates are scaled using the climatological vortex decay rate beyond 500 km to estimate the radius of 5 kt (1 kt = 0.514 m s−1) winds (R5) or TC size. A much larger historical record of TC-centered IR imagery (1978–2011) is then used to estimate TC sizes and form a global TC size climatology. The basin-specific distributions of TC size reveal that, among other things, the eastern North Pacific TC basins have the smallest while western North Pacific have the largest TC size distributions. The life cycle of TC sizes with respect to maximum intensity shows that TC growth characteristics are different among the individual TC basins, with the North Atlantic composites showing continued growth after maximum intensity. Small TCs are generally located at lower latitudes, westward steering, and preferred in seasons when environmental low-level vorticity is suppressed. Large TCs are generally located at higher latitudes, poleward steering, and preferred in enhanced low-level vorticity environments. Postmaximum intensity growth of TCs occurs in regions associated with enhanced baroclinicity and TC recurvature, while those that do not grow much are associated with west movement, erratic storm tracks, and landfall at or near the time of maximum intensity. With respect to climate change, no significant long-term trends are found in the dataset of TC size.


    After a Decade Are Atlantic Tropical Cyclone Gale Force Wind Radii Forecasts Now Skillful?

    Published Date: 2015
    Published By: American Meteorological Society

    The National Hurricane Center (NHC) has a long history of forecasting the radial extent of gale force or 34-knot (kt; where 1 kt = 0.51 m s−1) winds for tropical cyclones in their area of responsibility. These are referred to collectively as gale force wind radii forecasts. These forecasts are generated as part of the 6-hourly advisory messages made available to the public. In 2004, NHC began a routine of postanalysis or “best tracking” of gale force wind radii that continues to this day. At approximately the same time, a statistical wind radii forecast, based solely on climatology and persistence, was implemented so that NHC all-wind radii forecasts could be evaluated for skill. This statistical wind radii baseline forecast is also currently used in several applications as a substitute for or to augment NHC wind radii forecasts. This investigation examines the performance of NHC gale force wind radii forecasts in the North Atlantic over the last decade. Results presented within indicate that NHC’s gale force wind radii forecasts have increased in skill relative to the best tracks by several measures, and now significantly outperform statistical wind radii baseline forecasts. These results indicate that it may be time to reinvestigate whether applications that depend on wind radii forecast information can be improved through better use of NHC wind radii forecast information.